Wireless ultrasonic wavefield imaging via laser for hidden damage detection inside a steel box girder bridge

International Nuclear Information System (INIS)

An, Yun-Kyu; Song, Homin; Sohn, Hoon

2014-01-01

This paper presents a wireless ultrasonic wavefield imaging (WUWI) technique for detecting hidden damage inside a steel box girder bridge. The proposed technique allows (1) complete wireless excitation of piezoelectric transducers and noncontact sensing of the corresponding responses using laser beams, (2) autonomous damage visualization without comparing against baseline data previously accumulated from the pristine condition of a target structure and (3) robust damage diagnosis even for real structures with complex structural geometries. First, a new WUWI hardware system was developed by integrating optoelectronic-based signal transmitting and receiving devices and a scanning laser Doppler vibrometer. Next, a damage visualization algorithm, self-referencing f-k filter (SRF), was introduced to isolate and visualize only crack-induced ultrasonic modes from measured ultrasonic wavefield images. Finally, the performance of the proposed technique was validated through hidden crack visualization at a decommissioned Ramp-G Bridge in South Korea. The experimental results reveal that the proposed technique instantaneously detects and successfully visualizes hidden cracks even in the complex structure of a real bridge. (paper)

Design and test of box girder for a large wind turbine blade

DEFF Research Database (Denmark)

Nielsen, Per Hørlyk; Tesauro, Angelo; Bitsche, Robert

This report is covering the structural design and full scale test of a box girder as a part of the project “Demonstration of new blade design using manufacturing process simulations” supported by the EUDP program. A box girder with a predetermined outer geometry was designed using new inventions...... that the manufacturing process could include the new inventions. Subsequently the box girder was transported to the blade test facility at DTU Wind Energy. A series of test was performed with the blade to investigate the behaviour during loading, and finally the girder was loaded to ultimate failure. The report includes...... the description of the test setup, the test and an overview over the results from the test performed on the box girder. During the final test the box girder failed at 58 % of the expected ultimate load. Unfortunately, no definite conclusion could be made concerning the failure mechanism....

Bridge maintenance to enhance corrosion resistance and performance of steel girder bridges

Science.gov (United States)

Moran Yanez, Luis M.

The integrity and efficiency of any national highway system relies on the condition of the various components. Bridges are fundamental elements of a highway system, representing an important investment and a strategic link that facilitates the transport of persons and goods. The cost to rehabilitate or replace a highway bridge represents an important expenditure to the owner, who needs to evaluate the correct time to assume that cost. Among the several factors that affect the condition of steel highway bridges, corrosion is identified as the main problem. In the USA corrosion is the primary cause of structurally deficient steel bridges. The benefit of regular high-pressure superstructure washing and spot painting were evaluated as effective maintenance activities to reduce the corrosion process. The effectiveness of steel girder washing was assessed by developing models of corrosion deterioration of composite steel girders and analyzing steel coupons at the laboratory under atmospheric corrosion for two alternatives: when high-pressure washing was performed and when washing was not considered. The effectiveness of spot painting was assessed by analyzing the corrosion on steel coupons, with small damages, unprotected and protected by spot painting. A parametric analysis of corroded steel girder bridges was considered. The emphasis was focused on the parametric analyses of corroded steel girder bridges under two alternatives: (a) when steel bridge girder washing is performed according to a particular frequency, and (b) when no bridge washing is performed to the girders. The reduction of structural capacity was observed for both alternatives along the structure service life, estimated at 100 years. An economic analysis, using the Life-Cycle Cost Analysis method, demonstrated that it is more cost-effective to perform steel girder washing as a scheduled maintenance activity in contrast to the no washing alternative.

Suspension Bridge Flutter for Girder with Separate Control Flaps

DEFF Research Database (Denmark)

Huynh, T.; Thoft-Christensen, Palle

Active vibration control of long span suspension bridge flutter using separated control flaps (SFSC) has shown to increase effectively the critical wind speed of bridges. In this paper, an SFSC calculation based on modal equations of the vertical and torsional motions of the bridge girder including...... the flaps is presented. The length of the flaps attached to the girder, the flap configuration and the flap rotational angles are parameters used to increase the critical wind speed of the bridge. To illustrate the theory a numerical example is shown for a suspension bridge of 1000m+2500m+1000m span based...... on the Great Belt Bridge streamlined girder....

Design and construction of a cable-stayed composite girder bridge with precast RC-slabs; Purekyasuto shohan gosei keta shachokoyo no sekkei to seko

Energy Technology Data Exchange (ETDEWEB)

Maeda, K. [Tokyo Metropolitan Univ. (Japan). Faculty of Technology; Shimura, T.; Tachibana, Y.; Echigo, S. [Kawada Industries Inc., Tokyo (Japan)

1995-09-20

A report on design and execution of cable-stayed composite girder bridge with precast RC-slabs constructed first in Japan though in small scale was described. This bridge adopted steel slabs relatively low in slab height for main slab and with two boxes slab section, and was designed at an aim of being more economic and shorter in its working term in comparison with steel girder slab type, on a base of the design in a region allowable with the existing design standards. This bridge is mainly in accordance with the regulation on continuous bridge in the prescription of road bridge, and is designed for normal RC-girder selecting between girder supports to direction normal to bridge axis as usual without using specially strong concrete to the girder. And, in order to fill with the regulation on allowable tensile stress on considering effects of creep and drying shrinkage, a method adding prestress to the slabs was adopted. Furthermore, a loop-like overlap joint for cable joint for the precast girders, expansion concrete for joint portion to compose the girder with the steel slab and so forth were adopted. 12 refs., 22 figs., 5 tabs.

Behavior of Reinforced Concrete Hybrid Trapezoidal Box Girders Using Ordinary and Highly Strength Concrete

Directory of Open Access Journals (Sweden)

Nameer A. Alawsh

2018-03-01

Full Text Available In this paper, the general behavior of reinforced concrete hybrid box girders is studied by experimental and numerical investigation. Experimental work is included casting monolithically five specimens of box girders with trapezoidal cross section and testing it as simply supported under two point loading. Two specimens were cast as homogenous box girders (full normal strength concrete (NSC (about 35 MPa and full high strength concrete (HSC (about 55 MPa and three specimens were cast as hybrid box girders (HSC in upper flange only, HSC in upper flange and half depth of webs, and HSC in bottom flange and total depth of webs. Experimental results showed significant effects of concrete hybridization on the structural behavior of box girders specimens such as: cracking loads, cracking patterns, ultimate strengths, and failure modes. The ultimate strength of Hybrid box girders increased by 23% as average when compared with the homogenous box girder (full NSC and decreased by 9% as average when compared with homogenous box girder (full HSC. In numerical investigation, the tested specimens were modeled and analyzed using three dimensional non-linear finite element analysis. The analysis was carried out by using a computer program (ANSYS V16.1. The numerical results showed an acceptable agreement with the experimental work with difference about (3.12% and 9.588% as average for ultimate load and deflection, respectively.

Shear capacity of in service prestressed concrete bridge girders.

Science.gov (United States)

2010-05-17

The design of prestressed concrete bridge girders has changed significantly over the past several : decades. Specifically, the design procedure to calculate the shear capacity of bridge girders that : was used forty years ago is very different than t...

A Finite Segment Method for Skewed Box Girder Analysis

Directory of Open Access Journals (Sweden)

Xingwei Xue

2018-01-01

Full Text Available A finite segment method is presented to analyze the mechanical behavior of skewed box girders. By modeling the top and bottom plates of the segments with skew plate beam element under an inclined coordinate system and the webs with normal plate beam element, a spatial elastic displacement model for skewed box girder is constructed, which can satisfy the compatibility condition at the corners of the cross section for box girders. The formulation of the finite segment is developed based on the variational principle. The major advantage of the proposed approach, in comparison with the finite element method, is that it can simplify a three-dimensional structure into a one-dimensional structure for structural analysis, which results in significant saving in computational times. At last, the accuracy and efficiency of the proposed finite segment method are verified by a model test.

Condition Assessment of PCI Bridge Girder a Result of The Reduction Prestressing Force

Directory of Open Access Journals (Sweden)

Suangga Made

2014-03-01

Full Text Available PCI bridge girders is known and widely used for many construction e.g.: bridge, wharf, flyover, and other application. PC Bridge girders have two types: Pre - tensioned girders and post - tensioned girders. In pre tensioned girders, prestressing in carried out first then after that the fresh concrete poured. The prestressing process in only carried off after the concrete has sufficient strength. In this study, analysis was conducted for PCI bridge girder with span is 40 meters. Based on the data geometry bridge dimension girder, material girder, and material strands cable, it will be analyzed to calculate the natural frequencies and moment capacity using finite element program (Midas/Civil program. So it can be estimated how much the percentage reduction prestress force on the bridge until PCI bridge structure collapses. From the calculation, it found that the pattern comparison between reduction prestressing force and natural frequency are linear. These results are also similar for natural frequency versus moment capacity.PCI bridge will collapse when the reduction prestreesing force of 45 % to 50 % from the total loss of prestressing.

The effect of span length and girder type on bridge costs

Directory of Open Access Journals (Sweden)

Batikha Mustafa

2017-01-01

Full Text Available Bridges have an important role in impacting the civilization, growth and economy of cities from ancient time until these days due to their function in reducing transportation cost and time. Therefore, development of bridges has been a knowledge domain in civil engineering studies in terms of their types and construction materials to confirm a reliable, safe, economic design and construction. Girder-bridge of concrete deck and I-beam girder has been used widely for short and medium span bridges because of ease and low-cost of fabrication. However, many theoretical and practical investigations are still undertaken regarding the type of beam girder; i.e steel composite or prestressed concrete. This paper evaluates the effect of bridge span and the type of girder on the capital cost and life cycle costs of bridges. Three types of girders were investigated in this research: steel composite, pre-tensioned pre-stressed concrete and post-tensioned pre-stressed concrete. The structural design was analyzed for 5 span lengths: 20, 25, 30, 35 and 40m. Then, the capital construction cost was accounted for 15 bridges according to each span and construction materials. Moreover, the maintenance required for 50 years of bridge life was evaluated and built up as whole life costs for each bridge. As a result of this study, the influence of both span length and type of girder on initial construction cost and maintenance whole life costs were assessed to support the decision makers and designers in the selection process for the optimum solution of girder bridges.

Study on the Old Girders in the Widening Hollow Slab Girder Bridge

Science.gov (United States)

Wang, Ying; Zhang, Li Fang; Ma, Hai Yan

2018-06-01

Taking the bridge widening project of Shanghai-Hangzhou-Ningbo expressway widening construction project (China) as the background in this paper, the variation law of the internal force of the old bridge in the widening hollow slab girder bridge under vehicle load is studied, which is under the condition of different span lengths and different widening widths. Three different span lengths of the pre-tensioned prestressed hollow slab girder bridges are selected, the spatial finite element models of both the old bridge and the whole structure of widening bridge are established and calculated respectively by Midas/Civil software. The influences of widening and load increasing on the old bridges under the vehicle load are compared and analyzed. In addition, the authors also analyze the influences of different widening widths on the force state of old bridges under the condition of widening the same number of lane. Moreover , the effects on the old bridges that are caused by the uneven foundation settlement of widening bridge structure are also studied in this paper. This paper can provide some references for widening design of hollow slab bridges.

Structural health monitoring of an existing PC box girder bridge with distributed HCFRP sensors in a destructive test

Science.gov (United States)

Yang, Caiqian; Wu, Zhishen; Zhang, Yufeng

2008-06-01

The application of hybrid carbon fiber reinforced polymer (HCFRP) sensors was addressed to monitor the structural health of an existing prestressed concrete (PC) box girder bridge in a destructive test. The novel HCFRP sensors were fabricated with three types of carbon tows in order to realize distributed and broad-based sensing, which is characterized by long-gauge length and low cost. The HCFRP sensors were bonded on the bottom and side surfaces of the existing bridge to monitor its structural health. The gauge lengths of the sensors bonded on the bottom and side surfaces were 1.5 m and 1.0 m, respectively. The HCFRP sensors were distributed on the bridge for two purposes. One was to detect damage and monitor the structural health of the bridge, such as the initiation and propagation of new cracks, strain distribution and yielding of steel reinforcements. The other purpose was to monitor the propagation of existing cracks. The good relationship between the change in electrical resistance and load indicates that the HCFRP sensors can provide actual infrastructures with a distributed damage detection and structural health monitoring system. Corrections were made to this article on 13 May 2008. The corrected electronic version is identical to the print version.

Structural health monitoring of an existing PC box girder bridge with distributed HCFRP sensors in a destructive test

International Nuclear Information System (INIS)

Yang Caiqian; Wu Zhishen; Zhang Yufeng

2008-01-01

The application of hybrid carbon fiber reinforced polymer (HCFRP) sensors was addressed to monitor the structural health of an existing prestressed concrete (PC) box girder bridge in a destructive test. The novel HCFRP sensors were fabricated with three types of carbon tows in order to realize distributed and broad-based sensing, which is characterized by long-gauge length and low cost. The HCFRP sensors were bonded on the bottom and side surfaces of the existing bridge to monitor its structural health. The gauge lengths of the sensors bonded on the bottom and side surfaces were 1.5 m and 1.0 m, respectively. The HCFRP sensors were distributed on the bridge for two purposes. One was to detect damage and monitor the structural health of the bridge, such as the initiation and propagation of new cracks, strain distribution and yielding of steel reinforcements. The other purpose was to monitor the propagation of existing cracks. The good relationship between the change in electrical resistance and load indicates that the HCFRP sensors can provide actual infrastructures with a distributed damage detection and structural health monitoring system. Corrections were made to this article on 13 May 2008. The corrected electronic version is identical to the print version

Design aids of NU I-girders bridges.

Science.gov (United States)

2010-05-01

Precast prestressed concrete I-Girder bridges have become the most dominant bridge system in the United States. In the early design : stages, preliminary design becomes a vital first step in designing an economical bridge. Within the state of Nebrask...

Design of bridge crane girder strain acquisition system based on virtual instrument

Directory of Open Access Journals (Sweden)

Wenxue LIU

Full Text Available Girder is an important part of the bridge crane, which is also the main force element. In order to prevent accidents, it is necessary to collect the bridge crane girder stress data to analyse the fatigue life. This paper constructs a bridge crane girder strain acquisition system. The hardware system consists of sensors, connectors, data acquisition cards, wireless data transmission groups, POE power and host computer. The software system consists of NI MAX to interface with the computer's NI hardware and software resources,and LabVIEW programming to display and storage the girder strain data. Through this system, positions and working days strain data acquisition for the 50/10 t bridge crane girder gets the key positions strain data. The results show that the girder strain data acquisition system runs stably, channel signals of acquisition task transmit accurately, and the terminal data stores competely, meeting the detection requirements, which provides an important data support for the subsequent fatigue analysis and accurate remaining service life prediction of the crane girder.

Effect of longitudinal stiffening on bridge girder webs at incremental launching stage

Directory of Open Access Journals (Sweden)

Carlos Graciano

2015-01-01

Full Text Available Patch loading is a predominant load case at incremental bridge launching. Bridge girder webs are frequently provided with longitudinal stiffeners to increase in-service shear and bending strength, and its effect has been included in design codes. However, no straightforward rules are given to account for the influence of such stiffeners on improving the patch loading resistance. This paper presents a review of some available formulae found in the literature to estimate the girder ultimate strength including the provisions of the European, American and Colombian design codes. Additionally, a nonlinear finite element analysis is conducted on three case studies related to actual launched bridges. The case studies are also used to study the influence of the longitudinal stiffener and girder depth on the girder capacity. Different load-displacement responses are observed depending on the girder depth. Finally, the finite element analysis shows to what extent the longitudinal stiffeners can increase the patch loading capacity of bridge girder webs during launching.

Continuity diaphragm for skewed continuous span precast prestressed concrete girder bridges : technical summary report.

Science.gov (United States)

2004-03-01

Most highway bridges are built as cast-in-place : reinforced concrete slabs and prestressed concrete : girders. The shear connectors on the top of the girders : assure composite action between the slabs and : girders. The design guidelines for bridge...

Repair of Impact-Damaged Prestressed Bridge Girders Using Strand Splices and Fabric Reinforced Cementitious Matrix

OpenAIRE

Jones, Mark Stevens

2017-01-01

This thesis investigates the repair of impact-damaged prestressed concrete bridge girders with strand splices and fabric-reinforced cementitious matrix systems, specifically for repair of structural damage to the underside of an overpass bridge girder due to an overheight vehicle collision. Collision damage to bridges can range from minor to catastrophic, potentially requiring repair or replacement of a bridge girder. This thesis investigates the performance of two different types of repair...

A case study of interior low-frequency noise from box-shaped bridge girders induced by running trains: Its mechanism, prediction and countermeasures

Science.gov (United States)

Zhang, Xun; Li, Xiaozhen; Hao, Hong; Wang, Dangxiong; Li, Yadong

2016-04-01

A side effect of high-speed railway and urban rail transit systems is the associated vibration and noise. Since the use of concrete viaducts is predominant in railway construction due to scarce land resources, low-frequency (20-200 Hz) structure-radiated noise from concrete bridges is a principal concern. Although it is the most commonly used bridge type, the mechanism of noise emission from box-shaped bridge girders when subjected to impact forces from moving trains, which sounds like beating a drum, has not been well studied. In this study, a field measurement was first made on a simply-supported box-shaped bridge to record the acceleration of the slabs and the associated sound pressures induced by running trains. These data indicated that a significant beat-wave noise occurred in the box-shaped cavity when the train speed was around 340 km/h, which arose from the interference between two sound waves of 75.0 Hz and 78.8 Hz. The noise leakage from the bridge expansion joint was serious and resulted in obvious noise pollution near the bridge once the beat-wave noise was generated in the cavity. The dominant frequency of the interior noise at 75.0 Hz was confirmed from the spectrum of the data and the modal analysis results, and originated from the peak vibration of the top slab due to resonance and the first-order vertical acoustic mode, which led to cavity resonance, amplifying the corresponding noise. The three-dimensional acoustic modes and local vibration modes of the slab were calculated by using the finite element method. A simplified vehicle-track-bridge coupling vibration model was then developed to calculate the wheel-rail interaction force in a frequency range of 20-200 Hz. Numerical simulations using the boundary element method confirmed the cavity resonance effect and the numerical results agreed well with the data. Based on the calibrated numerical model, three noise reduction measures, i.e., adding a horizontal baffle in the interior cavity, narrowing

Effects of Adhesive Connection on Composite Action between FRP Bridge Deck and Steel Girder

NARCIS (Netherlands)

Jiang, X.; Luo, Chengwei; Qiang, X.; Kolstein, M.H.; Bijlaard, F.S.K.

2017-01-01

The FRP-steel girder composite bridge system is increasingly used in new constructions of bridges as well as rehabilitation of old bridges. However, the understanding of composite action between FRP decks and steel girders is limited and needs to be systematically investigated. In this paper,

Self-Consolidating Concrete for Prestressed Bridge Girders

Science.gov (United States)

2017-07-01

This document reports the findings of a research project designed to better understand material and structural performance of prestressed bridge girders made with Self-Consolidating Concrete (SCC) from Wisconsin. SCC has high potential to be used for...

Optimization of the box-girder of overhead crane with constrained ...

African Journals Online (AJOL)

haroun

Keywords: Overhead crane - Box-girder - New bat algorithm - level of ... much more efficiency and robustness compared to the genetic algorithm (GA) and PSO ...... optimization: developments, applications and resources," in Evolutionary.

Shear evaluation of tapered bridge girder panels with steel corrugated webs near the supports of continuous bridges

OpenAIRE

Zevallos, E.; Hassanein, M.F.; Real Saladrigas, Esther; Mirambell Arrizabalaga, Enrique

2016-01-01

Because of public construction budgets were cut over the last few years, new bridge girders with corrugated webs to reduce the construction costs have become more widely studied and used. In spite that tapered bridge girders with corrugated webs (BGCWs) are used in modern bridges, their shear strength and behaviour rarely exists in literature. Based on available literature, the web of the linearly tapered BGCWs may be divided into three typologies with different structural response to shear f...

Extension of POA based on Fiber Element to Girder Bridge

International Nuclear Information System (INIS)

Li Zhenxin; Qiang Shizhong

2010-01-01

Because of its main advantage of simplicity, practicality, lower computational cost and relative good results Pushover analysis (POA) has become an effective analytical tool during the last decade for the seismic assessment of buildings. But such work on bridges has been very limited. Hence, the aim of this study is to adapt POA for nonlinear seismic analysis of girder bridges, and investigate its applicability in the case of an existing river-spanning approach bridge. To three different types bridge models the nonlinear POA, which adopts fiber model nonlinear beam-column element based on flexibility approach, with return period about 2500 years is carried out. It can be concluded that POA is applicable for bridges, with some shortcomings associated with the method in general, even when it is applied for buildings. Finally the applicable selection for monitoring point and lateral load pattern is suggested according to dynamic characteristic of girder bridges.

Structural behavior of concrete box bridge using embedded FBG sensors

Science.gov (United States)

Chung, Wonseok; Kang, Donghoon

2012-04-01

For the structural monitoring of railway bridges, electromagnetic interference (EMI) is a significant problem as modern railway lines are powered by high-voltage electric power feeding systems. Fiber optic sensing systems are free from EMI and have been successfully applied in civil engineering fields. This study presents the application of fiber Bragg grating (FBG)-based sensing systems to precast concrete box railway bridges. A 20 m long full-scale precast concrete box railway girder was fabricated and tested in order to identify its static performance. The experimental program involved the measurement of the nonlinear static behavior until failure. Multiplexed FBG strain sensors were embedded along the length of steel rebar and a strain-induced wavelength shift was measured in order to monitor internal strains. The measured values from the FBG-based sensors are compared with the results using electric signal-based sensors. The results show that the FBG sensing system is promising and can improve the efficiency of structural monitoring for modern railway bridges.

Analytical Calculation And FEM Analysis Main Girder Double Girder Bridge Crane

Directory of Open Access Journals (Sweden)

Muamer Delić

2017-02-01

Full Text Available The cranes are now not replaceable mode of transport of materials and finished products both in production halls and in the open space. This paper made the whole analytical calculation of double girder bridge cranes to be used in laboratories exclusively for testing, determined by the maximum bending stress and deflection of the main girder. After calculating the dimensions, we created a model cranes in software CATIA V5. The same model was subjected to FEM analysis of the same name software. At the end of the paper comparison has been done. The objective of the calculation and analysis of the model was to develop a model crane and to serve for the next tests. Dimensions of the crane are given according to the laboratory where it will be located.

Numerical Analysis on Variation of Dynamic Response of Girder Bridges with Torsional Reinforcement Panels

Directory of Open Access Journals (Sweden)

Kang Jae-Yoon

2015-01-01

Full Text Available The dynamic flexural behaviour of the railway bridge is influenced by its torsional behaviour. Especially, in the case of girder railway bridges, the dynamic response tends to amplify when the natural frequency in flexure (1st vibration mode is close to that in torsion (2nd vibration mode. In order to prevent such situation, it is necessary to adopt a flexural-to-torsional natural frequency ratio larger than 120%. This study proposes a solution shifting the natural frequency in torsion to high frequency range and restraining torsion by installing concrete panels on the bottom flange of the girder so as to prevent the superposition of the responses in the girder bridge. The applicability of this solution is examined by finite element analysis of the shift of the torsional natural frequency and change in the dynamic response according to the installation of the concrete panels. The analytical results for a 30 m-span girder railway bridge indicate that installing the concrete panels increases the natural frequency in torsion by restraining the torsional behaviour and reduces also the overall dynamic response. It is seen that the installation of 100 mm-thick concrete panels along a section of 4 m at both extremities of the girder can reduce the dynamic response by more than 30%.

Analysis of structural diseases in widened structure due to the shrinkage and creep difference of new bridge

Science.gov (United States)

Wu, Wenqing; Zhang, Hui

2018-03-01

In order to investigate the possible structural diseases brought to the top flange of existing prestressed concrete box girder bridge due to the shrinkage and creep difference between new and old bridge, the stress state of the existing box girder before and after widening and the mechanisms of potential structural diseases were analyzed using finite element method in this paper. Results showed that the inner flange of the old box girder were generally in the state of large tensile stress, the main reason for which was the shrinkage and creep effect difference of the new and old bridge. And the tensile stress was larger than tensile strength of C50 concrete, which would most likely cause crack in the deck plate of box girder. Hence, reinforcement measures are needed to be designed carefully. Meanwhile, the transverse deformation of widened structure had exceeded the distance between the anti-seismic block and the web of box girder at the end cross section, which would squeeze anti-seismic block severely. Therefore, it is necessary to limit the length of continuous bridge in need of widening.

Continuity diaphragm for skewed continuous span precast prestressed concrete girder bridges.

Science.gov (United States)

2004-10-01

Continuity diaphragms used on skewed bents in prestressed girder bridges cause difficulties in detailing and : construction. Details for bridges with large diaphragm skew angles (>30) have not been a problem for LA DOTD. : However, as the skew angl...

Shear Behavior of Corrugated Steel Webs in H Shape Bridge Girders

Directory of Open Access Journals (Sweden)

Qi Cao

2015-01-01

Full Text Available In bridge engineering, girders with corrugated steel webs have shown good mechanical properties. With the promotion of composite bridge with corrugated steel webs, in particular steel-concrete composite girder bridge with corrugated steel webs, it is necessary to study the shear performance and buckling of the corrugated webs. In this research, by conducting experiment incorporated with finite element analysis, the stability of H shape beam welded with corrugated webs was tested and three failure modes were observed. Structural data including load-deflection, load-strain, and shear capacity of tested beam specimens were collected and compared with FEM analytical results by ANSYS software. The effects of web thickness, corrugation, and stiffening on shear capacity of corrugated webs were further discussed.

Self-Consolidating Concrete for Prestressed Bridge Girders : Research Brief

Science.gov (United States)

2017-08-01

Self-consolidating concrete (SCC) is commonly used as an alternative to conventional concrete (CC) in precast, prestressed concrete (PSC) bridge girders. The high strength, highly workable mixture can flow through dense reinforcement to fill formwork...

Flexural and Shear Behavior of FRP Strengthened AASHTO Type Concrete Bridge Girders

Directory of Open Access Journals (Sweden)

Nur Yazdani

2016-01-01

Full Text Available Fiber-reinforced polymers (FRP are being increasingly used for the repair and strengthening of deteriorated or unsafe concrete structures, including structurally deficient concrete highway bridges. The behavior of FRP strengthened concrete bridge girders, including failure modes, failure loads, and deflections, can be determined using an analytical finite element modeling approach, as outlined in this paper. The differences in flexural versus shear FRP strengthening and comparison with available design guidelines are also beneficial to design professionals. In this paper, a common AASHTO type prestressed concrete bridge girder with FRP wrapping was analyzed using the ANSYS FEM software and the ACI analytical approach. Both flexural and shear FRP applications, including vertical and inclined shear strengthening, were examined. Results showed that FRP wrapping can significantly benefit concrete bridge girders in terms of flexure/shear capacity increase, deflection reduction, and crack control. The FRP strength was underutilized in the section selected herein, which could be addressed through decrease of the amount of FRP and prestressing steel used, thereby increasing the section ductility. The ACI approach produced comparable results to the FEM and can be effectively and conveniently used in design.

Optimization of the box-girder of overhead crane with constrained ...

African Journals Online (AJOL)

Keywords: Overhead crane - Box-girder - New bat algorithm - level of comparison - Higher strength steel. Optimisation de poutre caisson de pont roulant avec un nouvel algorithme de chauve souris sous contrainte. Une conception optimale pour un poids minimal de la poutre principale d'un pont roulant peut réduire ...

Gust loading on streamlined bridge decks

DEFF Research Database (Denmark)

Larose, Guy; Mann, Jakob

1998-01-01

The current analytical description of the buffeting action of wind on long-span bridges is based on the strip assumption. However, recent experiments on closed-box girder bridge decks have shown that this assumption is not valid and is the source of an important part of the error margin...... of the analytical prediction methods. In this paper, an analytical model that departs from the strip assumption is used to describe the gust loading on a thin airfoil. A parallel is drawn between the analytical model and direct measurements of gust loading on motionless closed-box girder bridge decks. Empirical...

Evaluation of a highway bridge constructed using high strength lightweight concrete bridge girders.

Science.gov (United States)

2011-04-01

The use of high performance concretes to provide longer bridge spans has been limited due to the capacity of existing infrastructure to handle the load of the girders during transportation. The use of High Strength Lightweight Concrete (HSLW) can pro...

Shear in high strength concrete bridge girders : technical report.

Science.gov (United States)

2013-04-01

Prestressed Concrete (PC) I-girders are used extensively as the primary superstructure components in Texas highway bridges. : A simple semi-empirical equation was developed at the University of Houston (UH) to predict the shear strength of PC I-girde...

Effects of Adhesive Connection on Composite Action between FRP Bridge Deck and Steel Girder

Directory of Open Access Journals (Sweden)

Xu Jiang

2017-01-01

Full Text Available The FRP-steel girder composite bridge system is increasingly used in new constructions of bridges as well as rehabilitation of old bridges. However, the understanding of composite action between FRP decks and steel girders is limited and needs to be systematically investigated. In this paper, depending on the experimental investigations of FRP to steel girder system, the Finite Element (FE models on experiments were developed and analyzed. Comparison between experiments and FE results indicated that the FE models were much stiffer for in-plane shear stiffness of the FRP deck panel. To modify the FE models, rotational spring elements were added between webs and flanges of FRP decks, to simulate the semirigid connections. Numerical analyses were also conducted on four-point bending experiments of FRP-steel composite girders. Good agreement between experimental results and FE analysis was achieved by comparing the load-deflection curves at midspan and contribution of composite action from FRP decks. With the validated FE models, the parametric studies were conducted on adhesively bonded connection between FRP decks and steel girders, which indicated that the loading transfer capacity of adhesive connection was not simply dependent on the shear modulus or thickness of adhesive layer but dominated by the in-plane shear stiffness K.

STRENGTHENING CONCRETE HOLLOW SECTION GIRDER BRIDGE USING POLYURETHANE-CEMENT MATERIAL (PART B

Directory of Open Access Journals (Sweden)

Haleem K. Hussain

2018-01-01

Full Text Available This paper presents experimental study to retrofitted reinforced concrete Hollow Section Bridge. The study was carried out on the White River Bridge structure (Bai xi da Qiao / China. The effect of retrofitting on stress and strain of beams at the critical section was studied. Evaluating the bridges girder after strengthening using new material called PolyurethaneCement material (PUC as an external material .This study present the strain and deflection before and after strengthening the bridge girders. The results has shown that the overall state of the bridge structural strengthening is in good condition. The enhancement was significant in stiffness of the bridge structure. Regarding to the results of static load test, the experimental values strain and deflection are less than theoretical values, indicating that the stiffness of the structure, overall deformation and integrity satisfy the designed and standard requirements and the working performance are in good condition, and flexure capacity has a certain surplus.

Precast concrete elements for accelerated bridge construction : laboratory testing, field testing, evaluation of a precast concrete bridge, Madison County bridge.

Science.gov (United States)

2009-01-01

The importance of rapid construction technologies has been recognized by the Federal Highway Administration (FHWA) and the Iowa : DOT Office of Bridges and Structures. Recognizing this a two-lane single-span precast box girder bridge was constructed ...

Damage identification method for continuous girder bridges based on spatially-distributed long-gauge strain sensing under moving loads

Science.gov (United States)

Wu, Bitao; Wu, Gang; Yang, Caiqian; He, Yi

2018-05-01

A novel damage identification method for concrete continuous girder bridges based on spatially-distributed long-gauge strain sensing is presented in this paper. First, the variation regularity of the long-gauge strain influence line of continuous girder bridges which changes with the location of vehicles on the bridge is studied. According to this variation regularity, a calculation method for the distribution regularity of the area of long-gauge strain history is investigated. Second, a numerical simulation of damage identification based on the distribution regularity of the area of long-gauge strain history is conducted, and the results indicate that this method is effective for identifying damage and is not affected by the speed, axle number and weight of vehicles. Finally, a real bridge test on a highway is conducted, and the experimental results also show that this method is very effective for identifying damage in continuous girder bridges, and the local element stiffness distribution regularity can be revealed at the same time. This identified information is useful for maintaining of continuous girder bridges on highways.

Reflective Cracking between Precast Prestressed Box Girders

Science.gov (United States)

2017-06-30

The adjacent precast prestressed concrete box-beam bridge is the bridge of choice for short and short-to-medium span bridges. This choice is because of the ease of construction, favorable span-to-depth ratios, aesthetic appeal, and high torsional sti...

Creep analysis and torsional vibration analysis of cable-stayed bridges with two edge composite girders; Nishuketa gosei kozo shachokyo no creep kaiseki to nejiri shindo kaiseki

Energy Technology Data Exchange (ETDEWEB)

Hoshino, M. [Nihon University, Tokyo (Japan). College of Science and Technology

1996-07-21

This paper describes the creep analysis and torsional vibration analysis of cable-stayed bridges with two edge composite girders. The girder is composed of the concrete slab and the steel girder. I-girders are placed at both edges of the profile. Such a type of bridge was investigated. As the stress migrates by the creep of concrete slab, it is necessary to evaluate the influence of this creep precisely in designing. In the analysis, the composite girder was expressed not by the single member, but by the binary member consisting of concrete member and steel member. Two methods were employed, i.e., method A in which both members are connected by the rigid body beam and method B in which the profile of concrete is converted into the profile of steel. The method A provided better accuracy, but the method B was often sufficient. Torsional rigidity of the open profile structure was much smaller than that of the box profile. As the torsional natural frequency was low, proper torsional vibration analysis was indispensable especially from the viewpoint of wind resistance. Two methods were employed, which utilize the vibration analysis method for general space frame structures. Results of both methods were agreed mutually, but the second method provided better calculation efficiency. 10 refs., 9 figs., 6 tabs.

Numerical analysis of dynamic response of vehicle–bridge coupled system on long-span continuous girder bridge

Directory of Open Access Journals (Sweden)

Lipeng An

2016-07-01

Full Text Available To systematically study the vehicle–bridge coupled dynamic response and its change rule with different parameters, a vehicle model with seven degrees of freedom was built and the total potential energy of vehicle space vibration system was deduced. Considering the stimulation of road roughness, the dynamic response equation of vehicle–bridge coupled system was established in accordance with the elastic system principle of total potential energy with stationary value and the “set-in-right-position” rule. On the basis of the self-compiled Fortran program and bridge engineering, the dynamic response of long-span continuous girder bridge under vehicle load was studied. This study also included the calculation of vehicle impact coefficient, evaluation of vibration comfort, and analysis of dynamic response parameters. Results show the impact coefficient changes with lane number and is larger than the value calculated by the “general code for design of highway bridges and culverts (China”. The Dieckmann index of bridge vibration is also related to lane number, and the vibration comfort evaluation is good in normal conditions. The relevant conclusions from parametric analyses have practical significance to dynamic design and daily operation of long-span continuous girder bridges in expressways. Safety and comfort are expected to improve significantly with further control of the vibration of vehicle–bridge system.

Evaluation on Impact Interaction between Abutment and Steel Girder Subjected to Nonuniform Seismic Excitation

Directory of Open Access Journals (Sweden)

Yue Zheng

2015-01-01

Full Text Available This paper aims to evaluate the impact interaction between the abutment and the girder subjected to nonuniform seismic excitation. An impact model based on tests is presented by taking material properties of the backfill of the abutment into consideration. The conditional simulation is performed to investigate the spatial variation of earthquake ground motions. A two-span continuous steel box girder bridge is taken as the example to analyze and assess the pounding interaction between the abutment and the girder. The detailed nonlinear finite element (FE model is established and the steel girder and the reinforced concrete piers are modeled by nonlinear fiber elements. The pounding element of the abutment is simulated by using a trilinear compression gap element. The elastic-perfectly plastic element is used to model the nonlinear rubber bearings. The comparisons of the pounding forces, the shear forces of the nonlinear bearings, the moments of reinforced concrete piers, and the axial pounding stresses of the steel girder are studied. The made observations indicate that the nonuniform excitation for multisupport bridge is imperative in the analysis and evaluation of the pounding effects of the bridges.

Continuous prestressed concrete girder bridges, volume 2 : analysis, testing, and recommendations.

Science.gov (United States)

2016-12-01

The Texas Department of Transportation designs typical highway bridge structures as simple span systems using : standard precast, pretensioned girders. Spans are limited to about 150 ft due to weight and length restrictions on : transporting the prec...

Investigation and Control of VIVs with Multi-Lock-in Regions on Wide Flat Box Girders

Directory of Open Access Journals (Sweden)

Bo Wu

2017-01-01

Full Text Available On the preliminary designing of a wide flat box girder with the slenderness ratio 12, vertical and torsional vortex-induced vibrations (VIV are observed in wind tunnel tests. More than one lock-in region, which are defined as “multi-lock-in regions,” are recorded. Therefore, suspicions should be aroused regarding the viewpoint that wide box girders are aerodynamic friendly. As the three nascent vortexes originating at the pedestrian guardrails and inspection rails shed to near-wake through different pathways with different frequencies, the mechanisms of VIVs and multi-lock-in regions are analyzed to be determined by the inappropriate subsidiary structures. A hybrid method combining Large Eddy Simulation (LES with experimental results is introduced to study the flow-structure interactions (FSI when undergoing VIVs; the vortex mode of torsional VIV on wide flat box girders is defined as “4/2S,” which is different from any other known ones. Based on the mechanism of VIV, a new approach by increasing ventilation rate of the pedestrian guardrails is proved to be effective in suppressing vertical and torsional VIVs, and it is more feasible than other control schemes. Then, the control mechanisms are deeper investigated by analyzing the evolution of vortex mode and FSI using Hybrid-LES method.

Statistical determination of significant curved I-girder bridge seismic response parameters

Science.gov (United States)

Seo, Junwon

2013-06-01

Curved steel bridges are commonly used at interchanges in transportation networks and more of these structures continue to be designed and built in the United States. Though the use of these bridges continues to increase in locations that experience high seismicity, the effects of curvature and other parameters on their seismic behaviors have been neglected in current risk assessment tools. These tools can evaluate the seismic vulnerability of a transportation network using fragility curves. One critical component of fragility curve development for curved steel bridges is the completion of sensitivity analyses that help identify influential parameters related to their seismic response. In this study, an accessible inventory of existing curved steel girder bridges located primarily in the Mid-Atlantic United States (MAUS) was used to establish statistical characteristics used as inputs for a seismic sensitivity study. Critical seismic response quantities were captured using 3D nonlinear finite element models. Influential parameters from these quantities were identified using statistical tools that incorporate experimental Plackett-Burman Design (PBD), which included Pareto optimal plots and prediction profiler techniques. The findings revealed that the potential variation in the influential parameters included number of spans, radius of curvature, maximum span length, girder spacing, and cross-frame spacing. These parameters showed varying levels of influence on the critical bridge response.

Full scale test of a SSP 34m box girder 1. Data report; Reinforced glass fiber/expoxy used in wind turbine blades

Energy Technology Data Exchange (ETDEWEB)

Jensen, Find M.; Branner, K.; Nielsen, Per H. (and others)

2008-03-15

This report presents the setup and result of a full-scale test of a reinforced glass fibre/epoxy box girder used in 34m wind turbine blade. The tests were performed at the Blaest test facility in August 2006. The test is an important part of a research project established in cooperation between Risoe DTU, the National Laboratory for Sustainable Energy at the Technical University of Denmark -, SSP-Technology A/S and Blaest (Blade test centre A/S) and it has been performed as a part of Find Moelholt Jensen's PhD study. This report contains the complete test data for the final test, in which the box girder was loaded until failure. A comprehensive description of the test setup is given. This report deals only with tests and results. There are no conclusions on the data in this report, but references are given to publications, where the data are used and compared with FEM etc. Various kinds of measuring equipment have been used during these tests: acoustic emission, 330 strain gauges, 24 mechanical displacement devices and two optical deformation measuring systems. The mechanical displacement devices measured both global (absolute) and local (relative) deflection and the optical systems measured surface deformation. A prediction was made on the location of the failure of the girder. At this location the majority of the measuring equipment was concentrated. The prediction was proved to be correct and valuable information of the behaviour of the box girder prior to failure was obtained. The experimental investigation consisted of the following load configurations: -Flapwise bending -Torsion Ultrasonic scanning of the box girder was performed before, during and after the test the box girder. This was done to investigate whether the girder was damaged by the load or imperfection (productions defects) growth. (au)

Analysis of Temperature and Longitudinal Stress of Very Large Flat Steel Box Girder in Cold Areas%寒冷地区特大扁平钢箱梁温度及纵向应力分析

Institute of Scientific and Technical Information of China (English)

胡铁明; 苟红兵; 张冠华; 丁科翔

2015-01-01

为指导寒冷地区钢箱梁桥的设计 ,以主跨436 m的钢箱梁斜拉桥——辽河特大桥为研究对象 ,对其扁平钢箱梁进行了为期8个月的温度监测 ,采用对比分析、极值分析、概率统计等方法分析钢箱梁跨中截面温度及纵向应力日变化趋势、总体变化规律及温度对纵向应力的影响情况.结果表明 :环境温度在20~45 ℃时 ,桥梁设计规范计算得到的钢箱梁顶板温度最大值小于实际监测值 ;钢箱梁连续24 h温度变化服从正弦曲线分布 ,纵向应力每天前6 h变化服从线性分布 ,后18 h服从高斯曲线分布 ;24h内温度极值点时的温度效应为其它活荷载总效应的5.7~6.5倍 ;顶板冬季最冷月平均纵向应力相比夏季最热月低12~35 M Pa ,底板冬季最冷月平均纵向应力相比夏季低12~16 M Pa.%To direct the design of steel box girder bridge in cold areas , the Liaohe River Bridge ,a steel box girder cable-stayed bridge with a main span of 436 m ,was taken as the study background ,the flat steel box girder of which experienced temperature monitoring lasting 8 months.A series of analytical methods ,including contrastive analysis ,ultimate value analysis and probabilistic computing were adopted to analyze the trend of daily variation of midspan cross-sec-tion temperature and longitudinal stress of steel box girder as well as the general variation law and the effect of temperature on longitudinal stress.The results of the analysis indicate that the maxi-mum value of the top plate temperature of steel box girder calculated in accordance with the bridge design specification is less than the actual measured value w hen the ambient temperature is around 20~45℃.The 24 h continuous temperature variation of the steel box girder conforms to the sinu-soidal distribution ,the first 6 h variation of longitudinal stress in each day complies with linear dis-tribution and the following 18 h longitudinal stress variation obeys Gaussian

Monitoring system of arch bridge for safety network management

Science.gov (United States)

Joo, Bong Chul; Yoo, Young Jun; Lee, Chin Hyung; Park, Ki Tae; Hwang, Yoon Koog

2010-03-01

Korea has constructed the safety management network monitoring test systems for the civil infrastructure since 2006 which includes airport structure, irrigation structure, railroad structure, road structure, and underground structure. Bridges among the road structure include the various superstructure types which are Steel box girder bridge, suspension bridge, PSC-box-girder bridge, and arch bridge. This paper shows the process of constructing the real-time monitoring system for the arch bridge and the measured result by the system. The arch type among various superstructure types has not only the structural efficiency but the visual beauty, because the arch type superstructure makes full use of the feature of curve. The main measuring points of arch bridges composited by curved members make a difference to compare with the system of girder bridges composited by straight members. This paper also shows the method to construct the monitoring system that considers the characteristic of the arch bridge. The system now includes strain gauges and thermometers, and it will include various sensor types such as CCTV, accelerometers and so on additionally. For the long term and accuracy monitoring, the latest optical sensors and equipments are applied to the system.

A new solution of measuring thermal response of prestressed concrete bridge girders for structural health monitoring

International Nuclear Information System (INIS)

Jiao, Pengcheng; Borchani, Wassim; Hasni, Hassene; Lajnef, Nizar

2017-01-01

This study develops a novel buckling-based mechanism to measure the thermal response of prestressed concrete bridge girders under continuous temperature changes for structural health monitoring. The measuring device consists of a bilaterally constrained beam and a piezoelectric polyvinylidene fluoride transducer that is attached to the beam. Under thermally induced displacement, the slender beam is buckled. The post-buckling events are deployed to convert the low-rate and low-frequency excitations into localized high-rate motions and, therefore, the attached piezoelectric transducer is triggered to generate electrical signals. Attaching the measuring device to concrete bridge girders, the electrical signals are used to detect the thermal response of concrete bridges. Finite element simulations are conducted to obtain the displacement of prestressed concrete girders under thermal loads. Using the thermal-induced displacement as input, experiments are carried out on a 3D printed measuring device to investigate the buckling response and corresponding electrical signals. A theoretical model is developed based on the nonlinear Euler–Bernoulli beam theory and large deformation assumptions to predict the buckling mode transitions of the beam. Based on the presented theoretical model, the geometry properties of the measuring device can be designed such that its buckling response is effectively controlled. Consequently, the thermally induced displacement can be designed as limit states to detect excessive thermal loads on concrete bridge girders. The proposed solution sufficiently measures the thermal response of concrete bridges. (paper)

A new solution of measuring thermal response of prestressed concrete bridge girders for structural health monitoring

Science.gov (United States)

Jiao, Pengcheng; Borchani, Wassim; Hasni, Hassene; Lajnef, Nizar

2017-08-01

This study develops a novel buckling-based mechanism to measure the thermal response of prestressed concrete bridge girders under continuous temperature changes for structural health monitoring. The measuring device consists of a bilaterally constrained beam and a piezoelectric polyvinylidene fluoride transducer that is attached to the beam. Under thermally induced displacement, the slender beam is buckled. The post-buckling events are deployed to convert the low-rate and low-frequency excitations into localized high-rate motions and, therefore, the attached piezoelectric transducer is triggered to generate electrical signals. Attaching the measuring device to concrete bridge girders, the electrical signals are used to detect the thermal response of concrete bridges. Finite element simulations are conducted to obtain the displacement of prestressed concrete girders under thermal loads. Using the thermal-induced displacement as input, experiments are carried out on a 3D printed measuring device to investigate the buckling response and corresponding electrical signals. A theoretical model is developed based on the nonlinear Euler-Bernoulli beam theory and large deformation assumptions to predict the buckling mode transitions of the beam. Based on the presented theoretical model, the geometry properties of the measuring device can be designed such that its buckling response is effectively controlled. Consequently, the thermally induced displacement can be designed as limit states to detect excessive thermal loads on concrete bridge girders. The proposed solution sufficiently measures the thermal response of concrete bridges.

Continuous prestressed concrete girder bridges volume 1 : literature review and preliminary designs.

Science.gov (United States)

2012-06-01

The Texas Department of Transportation (TxDOT) is currently designing typical highway bridge structures as simply supported using standard precast, pretensioned girders. TxDOT is interested in developing additional economical design alternatives for ...

Full Scale Test of a SSP 34m box girder 1. Data report

DEFF Research Database (Denmark)

Jensen, Find Mølholt; Branner, Kim; Nielsen, Per Hørlyk

This report presents the setup and result of a full-scale test of a reinforced glass fibre/epoxy box girder used in 34m wind turbine blade. The tests were performed at the Blaest test facility in August 2006. The test is an important part of a research project established in cooperation between...... Risø DTU, the National Laboratory for Sustainable Energy at the Technical University of Denmark -, SSP-Technology A/S and Blaest (Blade test centre A/S) and it has been performed as a part of Find Mølholt Jensen‟s PhD study. This report contains the complete test data for the final test, in which...... the box girder was loaded until failure. A comprehensive description of the test setup is given. This report deals only with tests and results. There are no conclusions on the data in this report, but references are given to publications, where the data are used and compared with FEM etc. Various kinds...

Proposal and study of a long-span composite cable-stayed bridge with new hybrid girder; Atarashii gosei kozo shuketa wo mochiita chodai fukugo shachokyo no kenkyu

Energy Technology Data Exchange (ETDEWEB)

Yoshida, K.; Hishiki, Y.; Furuichi, K. [Kajima Corp., Tokyo (Japan)

1999-09-30

A hybrid or mixed structure (composite structures) are a matter of increasing concern which takes in each advantage of steel and concrete. A field of bridges is no exception, with the plan and construction carried out for the new type of composite bridge, such as a composite cable-stayed bridge and a composite extra dose bridge as a long span bridge, and a composite truss bridge and a corrugated steel plate web bridge as a medium-span bridge, with technological development becoming active in this field. In such a technological trend, a hybrid two-girder structure was devised, a structure consisting of a concrete filled steel pipe for a girder and a precast (PC) floor plate for a floor board, as the girder structure of a long-span cable-stayed bridge in the subject research; also, applicability was examined using, as an example, the composite cable-stayed bridge with hybrid girders employed for the span. This paper reports the result of the analysis of the entire system, the analysis made for the purpose of examining the characteristic and the feasibility of this hybrid girder. The analysis revealed the structural feasibility of the long-span composite cable-stayed bridge using two hybrid girders of concrete-filled steel pipes thus devised. (NEDO)

STUDY OF BRIDGE DECK A REVIEW

OpenAIRE

MISS. KSHITIJA S. BALWAN , MR. V. G. KHURD , MR. S. S. CHOUGULE

2018-01-01

The objective of this study was to understand the meaning of bridge deck. To know the different forms of decks used in bridge design. To understand different methods used for analysis of deck and study of box girder and its evolution

Development of a new-type super-long bridge; Chochotaikyo ni tekigoshita shinkeishiki kyoryo no kaihatsu

Energy Technology Data Exchange (ETDEWEB)

Ogawa, K.; Shimodoio, H.; Saito, T.; Nogami, C.; Oryu, T.; Morikawa, M. [Kawasaki Heavy Industries, Ltd., Kobe (Japan)

1998-12-20

In order to realize large strait-crossing projects in the near future, it is necessary to develop a new type of super-long span bridge, which has a superior aerodynamic stability and is cost effective. We have been proposed a new type of suspension bridge using a 2-box and 1-box combined girder to apply to such a project And this time, we propose the cable stayed suspension bridge using a 2- box and 1-box combined girder aiming for improvement of aerodynamic stability with increase of torsional rigidity. This paper describes the performance of this cable stayed suspension bridge obtained from aerodynamic analysis. As a result, it can be confirmed that this newly developed cable stayed suspension system has fine characteristics and shows more potential for economical construction than the early proposed suspension system. (author)

Seismic Performance of Multi-Span RC Railway Bridges

DEFF Research Database (Denmark)

Georgakis, Christos; Barrau, Xavier

2008-01-01

Presently, there is no clear method for determining the optimal railway bridge design for a particular ground type and expected seismic intensity. Four main types of RC bridge dominate the current multi-span railway bridge design trends – the Simply Supported Beam, Continuous Box-Girder (CBG), CBG...

Strength and durability of near-surface mounted CFRP bars for shear strengthening reinforced concrete bridge girders.

Science.gov (United States)

2012-03-01

During the interstate expansion of the 1950s, many conventionally reinforced concrete deck girder bridges were built throughout the country. These aging bridges commonly exhibit diagonal cracking and rate inadequately for shear, thus they are candida...

Strength and durability of near-surface mounted CFRP bars for shear strengthening reinforced concrete bridge girders : appendices.

Science.gov (United States)

2012-01-01

During the interstate expansion of the 1950s, many conventionally reinforced concrete deck girder bridges were built throughout the country. These aging bridges commonly exhibit diagonal cracking and rate inadequately for shear, thus they are candida...

Development of Embedded EM Sensors for Estimating Tensile Forces of PSC Girder Bridges

Science.gov (United States)

Kim, Ju-Won; Lee, Chaggil; Park, Seunghee

2017-01-01

The tensile force of pre-stressed concrete (PSC) girders is the most important factor for managing the stability of PSC bridges. The tensile force is induced using pre-stressing (PS) tendons of a PSC girder. Because the PS tendons are located inside of the PSC girder, the tensile force cannot be measured after construction using conventional NDT (non-destructive testing) methods. To monitor the induced tensile force of a PSC girder, an embedded EM (elasto-magnetic) sensor was proposed in this study. The PS tendons are made of carbon steel, a ferromagnetic material. The magnetic properties of the ferromagnetic specimen are changed according to the induced magnetic field, temperature, and induced stress. Thus, the tensile force of PS tendons can be estimated by measuring their magnetic properties. The EM sensor can measure the magnetic properties of ferromagnetic materials in the form of a B (magnetic density)-H (magnetic force) loop. To measure the B-H loop of a PS tendon in a PSC girder, the EM sensor should be embedded into the PSC girder. The proposed embedded EM sensor can be embedded into a PSC girder as a sheath joint by designing screw threads to connect with the sheath. To confirm the proposed embedded EM sensors, the experimental study was performed using a down-scaled PSC girder model. Two specimens were constructed with embedded EM sensors, and three sensors were installed in each specimen. The embedded EM sensor could measure the B-H loop of PS tendons even if it was located inside concrete, and the area of the B-H loop was proportionally decreased according to the increase in tensile force. According to the results, the proposed method can be used to estimate the tensile force of unrevealed PS tendons. PMID:28867790

Composite Action in Prestressed NU I-Girder Bridge Deck Systems Constructed with Bond Breakers to Facilitate Deck Removal : Technical Summary

Science.gov (United States)

2017-11-01

Results are reported from tests of small-scale push-off and large-scale composite NU I-girder specimens conducted to establish an interface connection detail that (1) Facilitates in-situ removal of the bridge deck without damaging prestressed girders...

Strength and durability of near-surface mounted CFRP bars for shear strengthening reinforced concrete bridge girders : final report.

Science.gov (United States)

2012-03-01

During the interstate expansion of the 1950s, many conventionally reinforced concrete deck girder bridges were built throughout the country. These aging bridges commonly exhibit diagonal cracking and rate inadequately for shear, thus they are candida...

Dynamic Responses of Continuous Girder Bridges with Uniform Cross-Section under Moving Vehicular Loads

OpenAIRE

Gao, Qingfei; Wang, Zonglin; Jia, Hongyu; Liu, Chenguang; Li, Jun; Guo, Binqiang; Zhong, Junfei

2015-01-01

To address the drawback of traditional method of investigating dynamic responses of the continuous girder bridge with uniform cross-section under moving vehicular loads, the orthogonal experimental design method is proposed in this paper. Firstly, some empirical formulas of natural frequencies are obtained by theoretical derivation and numerical simulation. The effects of different parameters on dynamic responses of the vehicle-bridge coupled vibration system are discussed using our own progr...

Structural Health Monitoring and Time-Dependent Effects Analysis of Self-Anchored Suspension Bridge with Extra-Wide Concrete Girder

Directory of Open Access Journals (Sweden)

Guangpan Zhou

2018-01-01

Full Text Available The present work is aimed at studying the structural health status of Hunan Road Bridge, which is currently the widest concrete self-anchored suspension bridge in China. The monitoring data included the structural deformations, internal forces, and vibration characteristics from April 2015 to April 2016 were analyzed to evaluate the structural changes and safety. The influences brought by the ambient temperature changes and the dual effects composed of concrete shrinkage & creep (S&C and seasonal temperature changes were analyzed based on the measured data. The long-time effects of concrete S&C were predicted using the CEB-FIP 90 model and the age-adjusted effective modulus method based on the ANSYS beam finite element model. The measured data showed that the transverse displacements of towers were more significant than the longitudinal ones. The spatial effect of the extra-wide girder is significant, which performs as the longitudinal stresses change unevenly along the transverse direction. The seasonal ambient warming caused overall increases in girder compressive stresses, and the cooling resulted in decreases along with significant temperature gradient effects. The prediction results show that the cable anchoring positions at girder ends and tower tops will move towards the mid-span affected by concrete S&C. In terms of the middle region of mid-span girder, significant increases in longitudinal stresses of top plate and decreases in the ones of bottom plate will be caused by the significant deflection. Comprehensively, the increases in the girder compressive stresses of side-span bottom plate and mid-span top plate are worthy of attention when confronted with extreme high temperature during the bridge service life cycle.

Strength and durability of near-surface mounted CFRP bars for shear strengthening reinforced concrete bridge girders : final report appendices.

Science.gov (United States)

2012-03-01

During the interstate expansion of the 1950s, many conventionally reinforced concrete deck girder bridges were built throughout the country. These aging bridges commonly exhibit diagonal cracking and rate inadequately for shear, thus they are candida...

Dynamic Magnification Factor in a Box-Shape Steel Girder

Science.gov (United States)

Rahbar-Ranji, A.

2014-01-01

The dynamic effect of moving loads on structures is treated as a dynamic magnification factor when resonant is not imminent. Studies have shown that the calculated magnification factors from field measurements could be higher than the values specified in design codes. It is the main aim of present paper to investigate the applicability and accuracy of a rule-based expression for calculation of dynamic magnification factor for lifting appliances used in marine industry. A steel box shape girder of a crane is considered and transient dynamic analysis using computer code ANSYS is implemented. Dynamic magnification factor is calculated for different loading conditions and compared with rule-based equation. The effects of lifting speeds, acceleration, damping ratio and position of cargo are examined. It is found that rule-based expression underestimate dynamic magnification factor.

Evaluating the performance of skewed prestressed concrete bridge after strengthening

Science.gov (United States)

Naser, Ali Fadhil; Zonglin, Wang

2013-06-01

The objectives of this paper are to explain the application of repairing and strengthening methods on the damaged members of the bridge structure, to analyze the static and dynamic structural response under static and dynamic loads after strengthening, and to evaluate the structural performance after application of strengthening method. The repairing and strengthening methods which are used in this study include treatment of the cracks, thickening the web of box girder along the bridge length and adding internal pre-stressing tendons in the thickening web, and construct reinforced concrete cross beams (diaphragms) between two box girders. The results of theoretical analysis of static and dynamic structural responses after strengthening show that the tensile stresses are decreased and become less than the allowable limit values in the codes. The values of vertical deflection are decreased after strengthening. The values of natural frequencies after strengthening are increased, indicating that the strengthening method is effective to reduce the vibration of the bridge structure. Therefore, the strengthening methods are effective to improve the bearing capacity and elastic working state of the bridge structure and to increase the service life of the bridge structure.

Assessment of vehicular live load and load factors for design of short-span bridges according to the new Egyptian Code

Directory of Open Access Journals (Sweden)

Hatem M. Seliem

2015-04-01

The study shows that concrete box-girders designed according to ECP-201:2012 and ECP-201:2003 using the ultimate limit state method yield almost the same demand. Despite the increase in the VLL of ECP-201:2012, and consequently the live load forces, concrete I-shaped girder bridges will be subjected to less total factored internal forces in comparison to ECP-201:2003 This is attributed to the interaction between the live to dead loads ratio and the load combinations. Design of composite steel plate girder bridges according to ECP-201:2012 using the allowable stress design method yields over designed sections.

Finite element model updating of multi-span steel-arch-steel-girder bridges based on ambient vibrations

Science.gov (United States)

Hou, Tsung-Chin; Gao, Wei-Yuan; Chang, Chia-Sheng; Zhu, Guan-Rong; Su, Yu-Min

2017-04-01

The three-span steel-arch-steel-girder Jiaxian Bridge was newly constructed in 2010 to replace the former one that has been destroyed by Typhoon Sinlaku (2008, Taiwan). It was designed and built to continue the domestic service requirement, as well as to improve the tourism business of the Kaohsiung city government, Taiwan. This study aimed at establishing the baseline model of Jiaxian Bridge for hazardous scenario simulation such as typhoons, floods and earthquakes. Necessities of these precaution works were attributed to the inherent vulnerability of the sites: near fault and river cross. The uncalibrated baseline bridge model was built with structural finite element in accordance with the blueprints. Ambient vibration measurements were performed repeatedly to acquire the elastic dynamic characteristics of the bridge structure. Two frequency domain system identification algorithms were employed to extract the measured operational modal parameters. Modal shapes, frequencies, and modal assurance criteria (MAC) were configured as the fitting targets so as to calibrate/update the structural parameters of the baseline model. It has been recognized that different types of structural parameters contribute distinguishably to the fitting targets, as this study has similarly explored. For steel-arch-steel-girder bridges in particular this case, joint rigidity of the steel components was found to be dominant while material properties and section geometries relatively minor. The updated model was capable of providing more rational elastic responses of the bridge superstructure under normal service conditions as well as hazardous scenarios, and can be used for manage the health conditions of the bridge structure.

Disassembly of an arch bridge deformed due to landslide activity and the replacement of a new bridge in the same site. Jisuberi ni yori henkei shita arch bashi no kaitai to shinbashi no kakekae

Energy Technology Data Exchange (ETDEWEB)

Sano, S; Morimoto, C; Tomoda, T; Mizukawa, Y; Onushi, M; Ito, T [Kawasaki Heavy Industries, Ltd., Tokyo (Japan)

1991-10-20

This report describes the replacement process of an arch bridge deformed due to landslide activity, selection and contents of the disassembly method, and configuration of the new bridge and its design method. The Ryugu Bridge had been damaged by landslides over an extended period. It was a deck arch bridge having originally a span of 74 meters, but it had shortened by 424 mm due to landslide activity during 14 years since its completion. Then it was decided to be replaced by a new bridge having an adjustable structure to support the movement of its abutments. As disassembly of the deformed arch bridge could be dangerous, the best methodology was studied, and the disassembly was carried out by the cable method. The new bridge had box-girder parts in both side of the main truss, so as to be adjustable to the change of the span length, and the bridge was designed for a working life of 50 years if the bearing supports and expansion joints were reset every 10 years. Concerning the connecting parts between the box-girder and the main truss, appropriateness of the sectional configuration was verified by FEM analysis. 9 refs., 18 figs., 2 tab.

Erection of the stiffening girder of the Akashi Kaikyo bridge; Akashi Kaikyo Ohashi hokoketa (sono 2) koji no genchi seko

Energy Technology Data Exchange (ETDEWEB)

Otsuki, M.; Inoue, M.; Ueno, Y.; Matsumura, T.; Oe, S. [Kawasaki Heavy Industries, Ltd., Kobe (Japan)

1998-12-20

The Akashi Kaikyo Bridge is 3,911m long with a center span of 1,991m, making it the longest suspension bridge in the world. Much careful attention has been given to the erection planning details in order to construct the bridge to withstand the harsh environmental conditions of that area. This report details the characteristics of the bridge stiffening girder and erection procedure, and the effects of the Hyogoken-Nanbu Earthquake. (author)

Nonlinear Stability Analysis of a Composite Girder Cable-Stayed Bridge with Three Pylons during Construction

Directory of Open Access Journals (Sweden)

Xiaoguang Deng

2015-01-01

Full Text Available Based on the nonlinear stability analysis method, the 3D nonlinear finite element model of a composite girder cable-stayed bridge with three pylons is established to research the effect of factors including geometric nonlinearity, material nonlinearity, static wind load, and unbalanced construction load on the structural stability during construction. Besides, the structural nonlinear stability in different construction schemes and the determination of temporary pier position are also studied. The nonlinear stability safety factors are calculated to demonstrate the rationality and safety of construction schemes. The results show that the nonlinear stability safety factors of this bridge during construction meet the design requirement and the minimum value occurs in the maximum double cantilever stage. Besides, the nonlinear stability of the structure in the side of edge-pylon meets the design requirement in the two construction schemes. Furthermore, the temporary pier can improve the structure stability, effectively, and the actual position is reasonable. In addition, the local buckling of steel girder occurs earlier than overall instability under load in some cable tension stages. Finally, static wind load and the unbalanced construction load should be considered in the stability analysis for the adverse impact.

Development of guidelines for transportation of prestressed concrete girders.

Science.gov (United States)

2011-11-01

"Prestressed concrete girders are an economical superstructure system for bridges. With the : advent of higher strength concretes and more effi cient cross sections, the use of long span (>100 : ft.) prestressed girders are now specifi ed. Such long ...

Repair of cracked prestressed concrete girders, I-565, Huntsville, Alabama.

Science.gov (United States)

2011-07-01

Wide cracks were discovered in prestressed concrete bridge girders shortly after their construction in Huntsville, Alabama. Previous investigations of these continuous-for-live-load girders revealed that the cracking resulted from restrained thermal ...

Design and construction of superstructure in prestressed concrete cable-stayed bridge. ; Aomori Bay Bridge. PC shachokyo jobuko no sekkei to seko. ; Aomori Bay Bridge

Energy Technology Data Exchange (ETDEWEB)

Ishibashi, T.; Fujimori, S.; Oba, M.; Tsuyoshi, T. (East Japan Railway Co., Tokyo (Japan))

1991-12-01

Aomori Bay Bridge is a 1,219m long elevated bridge, a part of No.2 Bay Highway of 1,993m in total length crossing over Aomori railway station which was planned in ordecr to integrate the port facilities of Aomori Harbor and expedite cargo traffic smoothly. Of this Bay Bridge, its main bridge portion crossing over Aomori railway station and the sea area was planned as a continuous prestressed concrete cable-stayed bridge of 498m in total length and consisting of three portions including the central portion in which the main span between the central bridge piers was 240m. It is scheduled to open in the summer of 1992. With regard to the design of this bridge, special care for the view of the bridge has been taken covering from the structure style to the accessories. For this bridge, a large scale underground continuous wall solid base with a box-shaped section consisting of 6 chambers was adopted for the base of a main tower. It has the cantilever suspension structure of the wide girder with the inverted Y-shaped pylons. For its stav cable, was adopted a large capacity stay cable with standard tensile strength of 1,942 fabricated on the site and for its covering tube, a FRP tube was adopted. In this article, the construction of the main girder and stay cables, and the construction control during their installation by projection are reported. 7 refs., 14 figs., 9 tabs.

Implementation and field evaluation of pretensioned concrete girder end crack control.

Science.gov (United States)

2016-05-01

Wisconsin bulb tee pretensioned concrete girders are currently used for bridge construction. Their efficiency in load resistance has made them particularly desirable. To provide that efficiency, these girders are heavily prestressed. Cracking is evid...

Active Control of Suspension Bridges

DEFF Research Database (Denmark)

Thoft-Christensen, Palle

In this paper some recent research on active control of very long suspension bridges, is presented. The presentation is based on research work at Aalborg University, Denmark. The active control system is based on movable flaps attached to the bridge girder. Wind load on bridges with or without...... flaps attached to the girder is briefly presented. A simple active control system is discussed. Results from wind tunnel experiments with a bridge section show that flaps can be used effectively to control bridge girder vibrations. Flutter conditions for suspension bridges with and without flaps...

stress distribution in continuo ribution in continuous thin ribution

African Journals Online (AJOL)

eobe

studied stresses in thin-walled box girder bridges but stress distribution walled box girder bridges .... the classical thin plate theory and trigonometric series. Lertsima et al. ..... remedied by applying spline finite strip method. Compared to other ...

Seismic Retrofit of a Multispan Prestressed Concrete Girder Bridge with Friction Pendulum Devices

Directory of Open Access Journals (Sweden)

Alberto Maria Avossa

2018-01-01

Full Text Available The paper deals with the proposal and application of a procedure for the seismic retrofit of an existing multispan prestressed concrete girder bridge defined explicitly for the use of friction pendulum devices as an isolation system placed between piers top and deck. First, the outcomes of the seismic risk assessment of the existing bridge, performed using an incremental noniterative Nonlinear Static Procedure, based on the Capacity Spectrum Method as well as the Inelastic Demand Response Spectra, are described and discussed. Then, a specific multilevel design process, based on a proper application of the hierarchy of strength considerations and the Direct Displacement-Based Design approach, is adopted to dimension the FPD devices. Furthermore, to assess the impact of the FPD nonlinear behaviour on the bridge seismic response, a device model that reproduces the variation of the normal force and friction coefficient, the bidirectional coupling, and the large deformation effects during nonlinear dynamic analyses was used. Finally, the paper examines the effects of the FPD modelling parameters on the behaviour of the retrofitted bridge and assesses its seismic response with the results pointing out the efficiency of the adopted seismic retrofit solution.

Behaviour of parallel girders stabilised with U-frames

DEFF Research Database (Denmark)

Virdi, Kuldeep; Azzi, Walid

2010-01-01

Lateral torsional buckling is a key factor in the design of steel girders. Stability can be enhanced by cross-bracing, reducing the effective length and thus increasing the ultimate capacity. U-frames are an option often used to brace the girders when designing through type of bridges and where...... overhead bracing is not practical. This paper investigates the effect of the U-frame spacing on the stability of the parallel girders. Eigenvalue buckling analysis was undertaken with four different spacings of the U-frames. Results were extracted from finite element analysis, interpreted and conclusions...

Evaluation of the Structure Stability of a Plate Girder Bridge Using MIDAS Structure Analysis

Energy Technology Data Exchange (ETDEWEB)

Kim, Eui Soo; Kim, Jong Hyuk [National Forensic Service, Wonju (Korea, Republic of)

2014-04-15

Recently, as a means of resolving the issue of legal liability in the event of an accident or a disaster, a wide variety of simulation techniques, such as structural and structure-fluid interaction analysis, have been used in the field of forensic engineering. The plate girder bridge discussed in this paper was being constructed between a pier and an abutment to expand an existing bridge, but an accident whereby the bridge overturned occurred at the end of the concrete laying process for a protective wall. This accident was caused by additional loads not being considered at the time of the design as well as the actual construction being different from the design. The additional loads ultimately generated a negative support force. In this study, we determined the cause of the accident by comparing the structural stability of the original design with that of the additional, non-conforming construction using MIDAS structural analysis.

Evaluation of the Structure Stability of a Plate Girder Bridge Using MIDAS Structure Analysis

International Nuclear Information System (INIS)

Kim, Eui Soo; Kim, Jong Hyuk

2014-01-01

Recently, as a means of resolving the issue of legal liability in the event of an accident or a disaster, a wide variety of simulation techniques, such as structural and structure-fluid interaction analysis, have been used in the field of forensic engineering. The plate girder bridge discussed in this paper was being constructed between a pier and an abutment to expand an existing bridge, but an accident whereby the bridge overturned occurred at the end of the concrete laying process for a protective wall. This accident was caused by additional loads not being considered at the time of the design as well as the actual construction being different from the design. The additional loads ultimately generated a negative support force. In this study, we determined the cause of the accident by comparing the structural stability of the original design with that of the additional, non-conforming construction using MIDAS structural analysis

Double Girder Bridge Crane with Double Cycling: Scheduling Strategy and Performance Evaluation

Directory of Open Access Journals (Sweden)

Dandan Wang

2014-01-01

Full Text Available This paper introduces a novel quay crane design, double girder bridge crane (DGBC. DGBC is capable of handling containers of two adjacent bays simultaneously, avoiding crane collisions, saving travelling and reposition cost, and eventually improving terminal efficiency. This problem is formulated as a resource-constrained project scheduling with objective to minimize the maximum completion time. A two-stage heuristic algorithm is proposed in which an operating sequences on each bay is obtained by double cycling, and the integrated timetable for both bays is constructed by solving resource conflicts using the proposed minimum cost strategy. We examine effectiveness and performance of applying DGBC with double cycling. A case study is presented to illustrate how DGBC works with the two-stage method. Three extreme cases with respective conflict types are investigated to develop the performance bounds of DGBC with double cycling. The results show that DGBC can significantly improve terminal productivity, and outperforms single girder crane in both makespan and the lift operation percentage. The highest DGBC efficiency does not require maximum double cycles in two bay schedules; rather the integrated timetable for two bays is the main contribution to the DGBC performance as it yields better cooperation between two spreaders and the driver.

Developing Extended Strands in Girder-Cap Beam Connections for Positive Moment Resistance

Science.gov (United States)

2017-11-01

In bridges constructed with precast prestressed concrete girders, resistance to seismic effects is achieved by the interaction between the columns, the cap beam and the girders. These components must be connected to provide flexural resistance. Under...

Analysis of a damaged and repaired pre-stressed concrete bridge girder by vehicle impact and effectiveness of repair procedure

OpenAIRE

Domínguez Mayans, Félix

2014-01-01

This thesis aims to study the structural consequences of the damages produced by vehicle impact in a pres-stressed concrete bridge girder and the repair procedure in a real case-study damaged after the bridge was opened to service. From the analysis of the situation of the beam and its damage state, a study of the repair actions carried out on this beam has been analyzed in order to determine the efficiency of the repair and if other alternatives are possible or more efficient. A stat...

Construction of Daiichi Tamagawa bridge; Daiichi Tamagawa kyoryo no seko

Energy Technology Data Exchange (ETDEWEB)

Watanabe, O.; Tsuyoshi, T. [East Japan Railway Company, Tokyo (Japan); Ota, T.; Sato, S. [Tekken Corp., Tokyo (Japan)

1997-05-30

This paper describes the construction of Daiichi Tamagawa Bridge for JR Tazawako Line, which was reconstructed with the Akita Shinkansen Project apart from the existing line. This bridge is a three-span continuous PC cable stayed bridge. To avoid operation accidents due to snow and ice, independent two-column type with a height of 11 m without beam was employed for the main tower. For the construction of upper part, overhang election construction method was adopted, which can be applied all the year round. The main girder has a single box cross section, and a width of 5.5 m and a beam height of 2.3 m. This was also constructed by the overhang construction method. To reduce the construction period, the main tower was constructed by the precast block construction method. The whole bridge was divided into six blocks by considering the hoist performance of cranes. Reinforcement against bearing pressure and cleavage due to the cable tensile force was conducted by adopting saddle structure for the main tower. Oblique members were jointed with the main girder using lateral beams projected from lateral side of girder. Totally seven PC cables were used for each oblique member. Measurements and management during the overhang construction were also described. The construction was over without problems in August, 1996. This bridge is under test operation using test run vehicles. 2 refs., 20 figs., 7 tabs.

Implementation of straight and curved steel girder erection design tools construction : summary.

Science.gov (United States)

2010-11-05

Project 0-5574 Curved Plate Girder Design for Safe and Economical Construction, resulted in the : development of two design tools, UT Lift and UT Bridge. UT Lift is a spreadsheet-based program for analyzing : steel girders during lifting while ...

Design and construction of Chichibu-park bridge. Chichibu Koenkyo (kasho) no sekkei to seko

Energy Technology Data Exchange (ETDEWEB)

Hasuike, H.; Azami, Y. (Saitama Prefectural Government Office, Saitama (Japan) New Structural Engineering, Ltd., Tokyo (Japan)); Yamamoto, T.

1994-01-31

The design and construction of the Chichibu-Park Bridge in Japan were outlined which is the symmetric 2-span continuous PC cable stayed road bridge with one main tower (530 m in total length, 392 m in main bridge length, 19 m in width) built over the Arakawa River. The double-suspended four-box main girder with wind noses was adopted because of its excellent torsional rigidity of area and wind proof stability, and the rigid-frame main girder was rigidly connected to the middle main tower. The main tower with an H-type hollow section was adopted considering its workability, and was assembled with its divided 18 blocks. Each side of the main girder was suspended at 30 points spaced at 6.0 m, and the tower ends of the diagonal cables were fixed to the partition inside the main tower taking a landscape into account. The thick stranded wires composed of fine PC steel stranded wires and covered with polyethylene were adopted as diagonal cables, and structural beams were used for both ends of the diagonal cables. Damping wires were also adopted to damp the diagonal cables. 9 refs., 12 figs., 6 tabs.

Assessment of Replacement Bridge using Proof Load Test

Science.gov (United States)

Sundru, Saibabu

2017-11-01

This work begins with an overview of the condition assessment of old bridge and explained reasons for demolishing of the bridge. Briefly presented flexural analysis of two stage post-tensioned prestressed concrete girder, which will be replace the old (new bridge). Construction of I-girder and composite girder at first stage and second stage prestressing respectively is explained with figures. Assessment of the load-caring capacity of the one span of the replacement bridge with simple supports using proof load test is presented which is mandatory according to Indian standards. Weighted sand bags were used to load the bridge up to a predetermined service load with impact factor. Deflections of the I-girders of the bridge were measured at selected locations along and across the bridge span and compared with computed values. Linear response was observed during loading and unloading. Considering the load test results, theoretical estimation and criteria as stipulated in codes of practice, it can be inferred that prestressed concrete I-girder bridge span has adequate capacity to carry the loads and hence, deemed to have passed the test.

Fatigue strength of the joint between diaphragms and longitudinal ribs in box section girders; Hako danmen keta no diaphragm to shita flange tateribu no kosabu no hiro kyodo

Energy Technology Data Exchange (ETDEWEB)

Miki, C.; Shiozaki, M.; Takeishi, K. [Tokyo Institute of Technology, Tokyo (Japan). Faculty of Engineering; Ohashi, H. [Honshu-Shikoku Bridge Authority, Tokyo (Japan)

1997-04-21

Discussions were given on crossing joints of diaphragms on hanger fixing sections and U-ribs on lower flanges in reinforcing box girders of a suspension bridge, as to their local stress generating behavior and effects of cope holes on fatigue strength. The test pieces have dimensions and shapes modeling the crossing joints, and the steel materials are SM490YA for upper and lower flanges and webs, and SS400 for U-ribs. The loading test was performed with four-point bending and at loading amplitudes of 30 to 45 tf. Furthermore, stress analysis was conducted by using the finite element method. The following conclusions were obtained as a result: local stress at cope hole tips decreases and fatigue strength increases with the smaller the cope hole diameter; when the cope holes are back-filled completely, deformation is concentrated on welds of the U-ribs and the flanges, generating high local stress; this reduces significantly the fatigue strength of details having no cope holes; and no particular differences are found on effects of boxing of the cope hole tips on the fatigue strength. 7 refs., 10 figs., 3 tabs.

Longest cable-stayed bridge TATARA; Longest shachokyo Tatara Ohashi

Energy Technology Data Exchange (ETDEWEB)

Fujii, K. [Hiroshima University, Hiroshima (Japan). Faculty of Engineering

1998-06-15

The world`s longest cable-stayed bridge Tatara having a central span of 890 m had the both ends closed in August 1997, linking Namakuchi Island and Omishima Island. Final finishing work is continuing for opening of the West Seto Expressway in the spring of 1999. A cable-stayed bridge supports the bridge girders by perpendicular components of tensile force of cables stayed obliquely. On the other hand, there is a concern that the girders may have axial compression force generated due to horizontal components of the force from the cable tensile force, which can cause buckling of the girders. Therefore, in order to suspend the girders efficiently by increasing the perpendicular components of the cable force, and moreover to suppress the axial compression force on the girders, it is more advantageous to make bridge towers high, hence the towers of this bridge are highest among the bridges on the Shimanami Ocean Road. This bridge whose long girders are stayed with 21-stage multi cables presented a problem in designing the buckling in steel girders near the towers due to the horizontal components of the force generated by the bridge. Discussions were given, therefore, by using load withstanding force experiments using a whole bridge model of 1/50 scale, buckling experiments on full-size reinforcing plate models, and load withstanding force analysis using a tower model. A number of other technical discussions were repeated, by which the world`s longest cable-stayed bridge was completed. 9 figs., 1 tab.

End region detailing of pretensioned concrete bridge girders.

Science.gov (United States)

2013-03-01

End region detailing has significant effect on the serviceability, behavior, and capacity of pretensioned concrete girders. : In this project, experimental and analytical research programs were conducted to evaluate and quantify the effects of : diff...

Field performance of timber bridges. 12, Christian Hollow stress-laminated box-beam bridge

Science.gov (United States)

J. P. Wacker; S. C. Catherman; R. G. Winnett

In January 1992, the Christian Hollow bridge was constructed in Steuben County, New York. The bridge is a single-span, stress-laminated box-beam superstructure that is 9.1 m long, 9.8 m wide, and 502 mm deep (30 ft long, 32 ft wide, and 19-3/4 in. deep). The performance of the bridge was continuously monitored for 28 months, beginning shortly after installation....

Evaluation of continuity detail for precast prestressed girders.

Science.gov (United States)

2011-08-01

The construction of highway bridges using precast prestressed concrete (PSC) girders is considered one of the most : economical construction alternatives because of the advantages they offer (e.g. reducing formwork and rapid construction). : Construc...

Fatigue strength of field welded joints in I-section girders of thick flange plates with cope hole details; Sukarappu wo yusuru atsuita I gata danmen keta genba yosetsu tsugitebu no hiro kyodo

Energy Technology Data Exchange (ETDEWEB)

Minami, K.; Miki, C.; Tateishi, K. [Tokyo Institute of Technology, Tokyo (Japan)

1997-10-15

Field welding an I-section girder forms details having scallop at the web, whereas the presence of the scallop causes shear deformation and localized stress concentration. Therefore the details in joints with low fatigue strength are ranked as class G in the fatigue design guideline published by JSSC. With special notice on the effect of shear, the present study has varied the phase by using multiple number of jacks; so loaded that the direction of the shear force will change; assumed field welding of a bridge constructed with a few number of main girders; and verified fatigue strength at thick flange plates. In addition, in order to improve the fatigue strength, elucidation was given on the effect of grinder finish at boxing welds. From these results, items to be considered were made clear when structural details are designed and fabricated, in which I-section girders having scallop are welded in fields. Furthermore, it was considered that stress in web plate jointing welding bead becomes relatively higher than local stress in boxing, which was indicated as a point requiring precaution. 8 refs., 20 figs., 2 tabs.

Field performance of timber bridges. 11, Spearfish Creek stress-laminated box-beam bridge

Science.gov (United States)

J. P. Wacker; M. A. Ritter; K. Stanfill-McMillan

The Spearfish Creek bridge was constructed in 1992 in Spearfish, South Dakota. It is a single-span, stress-laminated, box-beam superstructure. Performance of the bridge is being monitored for 5 years, beginning at installation. This report summarizes results for the first 3-1/2 years of monitoring and includes information on the design, construction, and field...

Construction of the Usui bridge. Chodai PC shachokyo no kensetsu (Joshin'etsu jidoshado Usuikyo)

Energy Technology Data Exchange (ETDEWEB)

Otani, S.; Ogata, T. (Japan Highway Public Corp., Tokyo (Japan))

1993-10-01

The Usui Bridge is a long bridge located at the Usui mountain pass on the Joshinetsu Expressway, completed in March 1993. This paper reports from its planning to the design, construction work, and construction management. The bridge is a first two-span continuous prestressed concrete cable-stayed bridge (with a length of 222 m) with one central cable plane ever constructed as a highway bridge in Japan. Its bridge construction features are represented by the main girder consisted of three-chamber type box girder, and the main tower of reversed Y-letter concrete structure. For the fan-shaped stay cable (9-step double cable), a large capacity cable of non-grouting type fabricated at a factory (with a tensile strength of 1500 tf class) was used to simplify the installation work at the site. The one-plane structure utilizing the center belt as a stay cable fixing portion was adopted because of its economic performance superior to a two-plane structure, easiness in consolidating construction works, and assurance of more open space for car traffic. After the completion, the bridge construction has been awarded with the Tanaka Prize of Japan Society of Civil Engineers and the PC Technology Association prize. 26 figs., 4 tabs.

SEISMIC BEHAVIOR OF STEEL MONORAIL BRIDGES UNDER TRAIN LOAD DURING STRONG EARTHQUAKES

OpenAIRE

KIM, C. W.; KAWATANI, M.; KANBARA, T.; NISHIMURA, N.

2013-01-01

This paper investigated dynamic responses of steel monorail bridges incorporating train-bridge interaction under strong earthquakes. Two types of steel monorail bridges were considered in the study: a conventional type with steel track-girder; an advanced type with composite track-girder and simplified lateral bracing system. During strong earthquakes, monorail train was assumed standing on the track-girder of monorail bridges. Observations through the analytical study showed that considering...

Christian Menn's recent bridge designs - Reducing structural elements to the simplest solution

OpenAIRE

Brühwiler, E.; Mahmoud, Khaled M.

2009-01-01

The conceptual designs by Christian Menn of four landmark bridges are presented: 1) a 350-m span cable-stayed bridge with jointless deck girder, 2) a cable-stayed bridge with a single “spindle-shaped” pylon, 3) a bridge with an arch reaching high above the deck (both carrying a horizontally curved deck girder), and 4) a cable stayed bridge with three pylons monolithically connected to the deck girder. All of the original bridge designs are driven by the aim to optimize the flow of force...

Design and construction of the Daini-Chikumagawa bridge; Dai ni Chikumagawa kyoryo no sekkei to seko

Energy Technology Data Exchange (ETDEWEB)

Inaba, N.; Takasusuki, K.; Hirasawa, T.; Kanamori, M.

1996-01-30

The Daini-Chikumagawa bridge, having spans of 134m {times} 2 which is the largest in Japan as the concrete railroad, is a prestressed concrete (PC) oblique cable-stayed bridge building on the Hokuriku Shinkansen express line which is constructing towards Nagano Olympic (Feb.1998). Regarding adoption of the oblique cable-stayed bridge for the railroad bridge, there are very few examples on a global scale and in Japan besides this bridge there is only one example (Omoto bridge (Iwate pref.), span = 85m). One H type tower (H = 65m from the surface of bridge) is erected at the center of the Chikuma river and then main girders are built at the front and rear of this tower. These main girders, being separated into 5m {times} 24 blocks per one side excepting surroundings of the tower, are fabricated as a three room box type PC block (total width 12.8m; height 3.0m) each on the river beach near the spot. These blocks are jointed from the tower side by the overhanging work using the constructing vehicles and are fixed with oblique materials (cables; two face hanging system) at intervals of 10m. 4 refs., 16 figs., 5 tabs.

Distortional Buckling Analysis of Steel-Concrete Composite Girders in Negative Moment Area

Directory of Open Access Journals (Sweden)

Zhou Wangbao

2014-01-01

Full Text Available Distortional buckling is one of the most important buckling modes of the steel-concrete composite girder under negative moment. In this study, the equivalent lateral and torsional restraints of the bottom flange of a steel-concrete composite girder under negative moments due to variable axial forces are thoroughly investigated. The results show that there is a coupling effect between the applied forces and the lateral and torsional restraint of the bottom flange. Based on the calculation formula of lateral and torsional restraints, the critical buckling stress of I-steel-concrete composite girders and steel-concrete composite box girders under variable axial force is obtained. The critical bending moment of the steel-concrete composite girders can be further calculated. Compared to the traditional calculation methods of elastic foundation beam, the paper introduces an improved method, which considers coupling effect of the external loads and the foundation spring constraints of the bottom flange. Fifteen examples of the steel-concrete composite girders in different conditions are calculated. The calculation results show a good match between the hand calculation and the ANSYS finite element method, which validated that the analytic calculation method proposed in this paper is practical.

Effects of CFRP Strengthening on Dynamic and Fatigue Responses of Composite Bridge

Directory of Open Access Journals (Sweden)

Kittisak Kuntiyawichai

2014-01-01

Full Text Available This paper investigates the effect of CFRP strengthening on dynamic and fatigue responses of composite bridge using finite element program ABAQUS. Dynamic and fatigue responses of composite bridge due to truck load based on AASHTO standard are investigated. Two types of CFRP strengthening techniques, CFRP sheets and CFRP deck, are applied to both the damaged and undamaged bridges. For the case of damaged bridge, two through-thickness crack sizes, 3 mm and 6 mm in depth, are assumed at midspan of the steel girders. Furthermore, effects of the number of steel girders on the dynamic and fatigue responses are also considered. The results show that the maximum responses of composite bridges occur for dual lane cases. By using CFRP as a strengthening material, the maximum stress and deflection of the steel girders reduce and consequently increase the fatigue life of the girders. After introducing initial crack into the steel girders of the composite bridges, the fatigue life of the bridges is dramatically reduced. However, the overall performance of the damaged composite bridge can be improved by using CFRP, albeit with less effectiveness. Therefore, if cracks are found, steel welding must be performed before strengthening the composite bridge by CFRP.

Experimental testing of post-tensioned concrete girders instrumented with optical fibre gratings

Science.gov (United States)

Matthys, S.; Taerwe, L.

2005-05-01

The integration of optical fibre strain sensors in concrete structures in order to measure deformations has proven to be successful in several applications. Examples of monitored structures by the Magnel Laboratory for Concrete Research are a concrete girder bridge over the Ring Canal by Ghent, a Quay wall at the Ring Canal and a trough girder containing a railway track of a bridge [1,2]. Based on a joint research project the feasibility of integrating Bragg grating sensors in concrete in order to statically and dynamically monitor 17.6 m long prestressed concrete girders has been investigated. During the project 3 post-tensioned concrete girders were tested, submitting them to static and dynamic loading conditions and monitoring the structural behavior with several types of measuring devices, including accelerometers, Bragg gratings, Fabry-Perot gratings, deformeters, crack microscopes, etc. The obtained test results demonstrate the feasibility of optical strain sensors for both static and dynamic measurements. Though it was demonstrated, in the case of dynamic monitoring, that optical strain measurements can be used to directly measure the modal strains, the project also demonstrated that for prestressed concrete the variation in dynamic parameters was insufficient for adequate dynamic monitoring and related damage diagnostics.

Dynamic Responses of Continuous Girder Bridges with Uniform Cross-Section under Moving Vehicular Loads

Directory of Open Access Journals (Sweden)

Qingfei Gao

2015-01-01

Full Text Available To address the drawback of traditional method of investigating dynamic responses of the continuous girder bridge with uniform cross-section under moving vehicular loads, the orthogonal experimental design method is proposed in this paper. Firstly, some empirical formulas of natural frequencies are obtained by theoretical derivation and numerical simulation. The effects of different parameters on dynamic responses of the vehicle-bridge coupled vibration system are discussed using our own program. Finally, the orthogonal experimental design method is proposed for the dynamic responses analysis. The results show that the effects of factors on dynamic responses are dependent on both the selected position and the type of the responses. In addition, the interaction effects between different factors cannot be ignored. To efficiently reduce experimental runs, the conventional orthogonal design is divided into two phases. It has been proved that the proposed method of the orthogonal experimental design greatly reduces calculation cost, and it is efficient and rational enough to study multifactor problems. Furthermore, it provides a good way to obtain more rational empirical formulas of the DLA and other dynamic responses, which may be adopted in the codes of design and evaluation.

The Vibration Based Fatigue Damage Assessment of Steel and Steel Fiber Reinforced Concrete (SFRC Composite Girder

Directory of Open Access Journals (Sweden)

Xu Chen

2015-01-01

Full Text Available The steel-concrete composite girder has been usually applied in the bridge and building structures, mostly consisting of concrete slab, steel girder, and shear connector. The current fatigue damage assessment for the composite girder is largely based on the strain values and concrete crack features, which is time consuming and not stable. Hence the vibration-based fatigue damage assessment has been considered in this study. In detail, a steel-steel fiber reinforced concrete (SFRC composite girder was tested. The steel fiber reinforced concrete is usually considered for dealing with the concrete cracks in engineering practice. The composite girder was 3.3m long and 0.45m high. The fatigue load and impact excitation were applied on the specimen sequentially. According to the test results, the concrete crack development and global stiffness degradation during the fatigue test were relatively slow due to the favourable performance of SFRC in tension. But on the other hand, the vibration features varied significantly during the fatigue damage development. Generally, it confirmed the feasibility of executing fatigue damage assessment of composite bridge based on vibration method.

Development of guidelines for transportation of long prestressed concrete girders.

Science.gov (United States)

2016-12-01

This research study investigates the behavior of two long prestressed concrete girders during lifting and : transportation from the precast yard to the bridge site, with a particular focus on cracking concerns : during transport. Different response m...

Evaluation of continuity detail for precast prestressed girders : tech summary.

Science.gov (United States)

2011-08-01

Building multi-simple span bridges using precast prestressed concrete girders is an easy construction. However, the existence of : expansion joints often leads to a host of problems in their vicinity due to drainage leaks. Furthermore, debris accumul...

Bridges analysis, design, structural health monitoring, and rehabilitation

CERN Document Server

Bakht, Baidar

2015-01-01

This book offers a valuable guide for practicing bridge engineers and graduate students in structural engineering; its main purpose is to present the latest concepts in bridge engineering in fairly easy-to-follow terms. The book provides details of easy-to-use computer programs for: ·      Analysing slab-on-girder bridges for live load distribution. ·      Analysing slab and other solid bridge components for live load distribution. ·      Analysing and designing concrete deck slab overhangs of girder bridges under vehicular loads. ·      Determining the failure loads of concrete deck slabs of girder bridges under concentrated wheel loads. In addition, the book includes extensive chapters dealing with the design of wood bridges and soil-steel bridges. Further, a unique chapter on structural health monitoring (SHM) will help bridge engineers determine the actual load carrying capacities of bridges, as opposed to their perceived analytical capacities. The chapter addressing structures...

Geometric nonlinear analysis of self-anchored cable-stayed suspension bridges.

Science.gov (United States)

Hui-Li, Wang; Yan-Bin, Tan; Si-Feng, Qin; Zhe, Zhang

2013-01-01

Geometric nonlinearity of self-anchored cable-stayed suspension bridges is studied in this paper. The repercussion of shrinkage and creep of concrete, rise-to-span ratio, and girder camber on the system is discussed. A self-anchored cable-stayed suspension bridge with a main span of 800 m is analyzed with linear theory, second-order theory, and nonlinear theory, respectively. In the condition of various rise-to-span ratios and girder cambers, the moments and displacements of both the girder and the pylon under live load are acquired. Based on the results it is derived that the second-order theory can be adopted to analyze a self-anchored cable-stayed suspension bridge with a main span of 800 m, and the error is less than 6%. The shrinkage and creep of concrete impose a conspicuous impact on the structure. And it outmatches suspension bridges for system stiffness. As the rise-to-span ratio increases, the axial forces of the main cable and the girder decline. The system stiffness rises with the girder camber being employed.

Geometric Nonlinear Analysis of Self-Anchored Cable-Stayed Suspension Bridges

Directory of Open Access Journals (Sweden)

Wang Hui-Li

2013-01-01

Full Text Available Geometric nonlinearity of self-anchored cable-stayed suspension bridges is studied in this paper. The repercussion of shrinkage and creep of concrete, rise-to-span ratio, and girder camber on the system is discussed. A self-anchored cable-stayed suspension bridge with a main span of 800 m is analyzed with linear theory, second-order theory, and nonlinear theory, respectively. In the condition of various rise-to-span ratios and girder cambers, the moments and displacements of both the girder and the pylon under live load are acquired. Based on the results it is derived that the second-order theory can be adopted to analyze a self-anchored cable-stayed suspension bridge with a main span of 800 m, and the error is less than 6%. The shrinkage and creep of concrete impose a conspicuous impact on the structure. And it outmatches suspension bridges for system stiffness. As the rise-to-span ratio increases, the axial forces of the main cable and the girder decline. The system stiffness rises with the girder camber being employed.

Verification of LRFD Bridge Design and Analysis Software for INDOT

OpenAIRE

Varma, Amit H.; Seo, Jungil

2009-01-01

NCHRP Process 12-50 was implemented to evaluate and verify composite steel I-girder bridge design software used commonly in Indiana. A test-bed of twenty one bridges was developed with the guidance from an Indiana Department of Transportation appointed research advisory panel (RAP). The test-bed included five simple-span and sixteen multi-span bridge superstructures. More than 80 parameters were required to define a bridge and they include bridge span, girder spacing, number of beams, section...

Comprehensive evaluation of fracture critical bridges.

Science.gov (United States)

2014-02-01

Two-girder steel bridges are classified as fracture critical bridges based on the definition given in the AASHTO LRFD Bridge Design Specifications. In a fracture critical bridge a failure of a tension member leads to collapse of the bridge. However, ...

Puentes extradosados: evolución y tendencias actuales

Directory of Open Access Journals (Sweden)

José Miguel Benjumea Royero

2012-09-01

Full Text Available Since their appearance in 1994, extradosed bridges have played an important role in road and railway projects, competing (in medium span lengths with cables-stayed and prestressed box girder bridges. At a regional level, extradosed bridges have been implemented more frequently in Asia, but recent projects developed in Europe and America show a growing interest in this typology. Consequently, this paper is aimed at offering a survey viewpoint on the evolution of extradosed bridges, from their origin to their current applications. This paper is also intended to show the adopted structural trends by presenting existing extradosed bridges, bridges under construction, and newly designed bridges. Finally, the main advantages and disadvantages of this type of bridges are analyzed and compared to cable-stayed and prestressed box girder bridges.

Live-Load Testing Application Using a Wireless Sensor System and Finite-Element Model Analysis of an Integral Abutment Concrete Girder Bridge

Directory of Open Access Journals (Sweden)

Robert W. Fausett

2014-01-01

Full Text Available As part of an investigation on the performance of integral abutment bridges, a single-span, integral abutment, prestressed concrete girder bridge near Perry, Utah was instrumented for live-load testing. The live-load test included driving trucks at 2.24 m/s (5 mph along predetermined load paths and measuring the corresponding strain and deflection. The measured data was used to validate a finite-element model (FEM of the bridge. The model showed that the integral abutments were behaving as 94% of a fixed-fixed support. Live-load distribution factors were obtained using this validated model and compared to those calculated in accordance to recommended procedures provided in the AASHTO LRFD Bridge Design Specifications (2010. The results indicated that if the bridge was considered simply supported, the AASHTO LRFD Specification distribution factors were conservative (in comparison to the FEM results. These conservative distribution factors, along with the initial simply supported design assumption resulted in a very conservative bridge design. In addition, a parametric study was conducted by modifying various bridge properties of the validated bridge model, one at a time, in order to investigate the influence that individual changes in span length, deck thickness, edge distance, skew, and fixity had on live-load distribution. The results showed that the bridge properties with the largest influence on bridge live-load distribution were fixity, skew, and changes in edge distance.

An overheight vehicle bridge collision monitoring system using piezoelectric transducers

Science.gov (United States)

Song, G.; Olmi, C.; Gu, H.

2007-04-01

With increasing traffic volume follows an increase in the number of overheight truck collisions with highway bridges. The detection of collision impact and evaluation of the impact level is a critical issue in the maintenance of a concrete bridge. In this paper, an overheight collision detection and evaluation system is developed for concrete bridge girders using piezoelectric transducers. An electric circuit is designed to detect the impact and to activate a digital camera to take photos of the offending truck. Impact tests and a health monitoring test were conducted on a model concrete bridge girder by using three piezoelectric transducers embedded before casting. From the experimental data of the impact test, it can be seen that there is a linear relation between the output of sensor energy and the impact energy. The health monitoring results show that the proposed damage index indicates the level of damage inside the model concrete bridge girder. The proposed overheight truck-bridge collision detection and evaluation system has the potential to be applied to the safety monitoring of highway bridges.

Long-Term Effects of Super Heavy-Weight Vehicles on Bridges

OpenAIRE

Wood, Scott M.; Akinci, Necip Onder; Liu, Judy; Bowman, Mark D

2007-01-01

A permit truck which exceeds the predefined limit of 108 kips is defined as a superload in Indiana. This study was conducted to examine the long-term effects of superload trucks on the performance of typical slab-on-girder bridges and to assess the likelihood of causing immediate damage. Typical steel and prestressed concrete slab-on-girder type bridges were analyzed using both beam line analysis and detailed finite element models. Furthermore, one prestressed concrete bridge and one steel br...

Design and construction of Ogawa bridge; Ogawa bashi no sekkei to seko

Energy Technology Data Exchange (ETDEWEB)

Hori, T.; Chigira, F. [Kajima Corp., Tokyo (Japan); Sakao, H.

1995-09-30

Ogawa bridge 230m long by 15.5m wide has been planned on the national road No.401 at Katashina-mura in Gunma Prefecture. Structure mode is two spans continuous PC cable-stayed obliquely system, and a main tower is H type (height: 56m from the road surface) and is located at the center of the bridge alone. This place corresponding to the entrance of Oze famous national park, the main tower is designed so as to have bulge, imaging Mizubasho (lysichiton camtschatcense), from the middle part of the pier to the lower part of the main tower. Arrangement of the cables is designed as two faces of hung fun type and one side face is composed of 13 steel strands (dia. 15.2mm wire x 27 (partly 19); covered with PE tube) in front and rear respectively. A main girder is the box type PC block 2.3m height by 4m or 3m long, and 3m long one is for fastening with a cable. Centering on the main tower, the girder blocks are successively connected in front and rare alternatively and are fastened with cables in part. This overhanging connection work is carried out by two special movable conveyers `Wagens`. 26 figs., 2 tabs.

Nonlinear seismic analysis of continuous RC bridge

Directory of Open Access Journals (Sweden)

Čokić Miloš M.

2017-01-01

Full Text Available Nonlinear static analysis, known as a pushover method (NSPA is oftenly used to study the behaviour of a bridge structure under the seismic action. It is shown that the Equivalent Linearization Method - ELM, recommended in FEMA 440, is appropriate for the response analysis of the bridge columns, with different geometric characteristics, quantity and distribution of steel reinforcement. The subject of analysis is a bridge structure with a carriageway plate - a continuous beam with three spans, with the 24 + 40 + 24 m range. Main girder is made of prestressed concrete and it has a box cross section of a constant height. It is important to study the behaviour, not only in the transverse, but also in the longitudinal direction of the bridge axis, when analysing the bridge columns exposed to horizontal seismic actions. The columns were designed according to EN1992, parts 1 and 2. Seismic action analysis is conducted according to EN 1998: 2004 standard. Response spectrum type 1, for the ground type B, was applied and the analysis also includes 20% of traffic load. The analysis includes the values of columns displacement and ductility. To describe the behaviour of elements under the earthquake action in both - longitudinal and transverse direction, pushover curves were formed.

Lateral dynamic interaction analysis of a train girder pier system

Science.gov (United States)

Xia, H.; Guo, W. W.; Wu, X.; Pi, Y. L.; Bradford, M. A.

2008-12-01

A dynamic model of a coupled train-girder-pier system is developed in this paper. Each vehicle in a train is modeled with 27 degrees-of-freedom for a 4-axle passenger coach or freight car, and 31 for a 6-axle locomotive. The bridge model is applicable to straight and curved bridges. The centrifugal forces of moving vehicles on curved bridges are considered in both the vehicle model and the bridge model. The dynamic interaction between the bridge and train is realized through an assumed wheel-hunting movement. A case study is performed for a test train traversing two straight and two curved multi-span bridges with high piers. The histories of the train traversing the bridges are simulated and the dynamic responses of the piers and the train vehicles are calculated. A field experiment is carried out to verify the results of the analysis, by which the lateral resonant train speed inducing the peak pier-top amplitudes and some other observations are validated.

CFRP-Strengthening and Long-Term Performance of Fatigue Critical Welds of a Steel Box Girder

Directory of Open Access Journals (Sweden)

Roland E. Koller

2014-02-01

Full Text Available Empa’s research efforts in the 1990s provided evidence that a considerable increase of the fatigue strength of welded aluminum beams can be achieved by externally bonding pultruded carbon fiber reinforced polymer (CFRP laminates using rubber-toughened epoxies over the fatigue-weak welding zone on their tensile flange. The reinforcing effect obtained is determined by the stiffness of the unidirectional CFRP laminate which has twice the elastic modulus of aluminum. One can therefore easily follow that an unstressed CFRP laminate reinforcement of welded beams made of steel will not lead to a substantial increase in fatigue strength of the steel structure. This consideration led to the idea of prestressing an external reinforcement of the welded zone. The present investigation describes experimental studies to identify the adhesive system suitable for achieving high creep and fatigue strength of the prestressed CFRP patch. Experimental results (Wöhler-fields of shear-lap-specimens and welded steel beams reinforced with prestressed CFRP laminates are presented. The paper concludes by presenting a field application, the reinforcement of a steel pendulum by adhesively bonded prestressed CFRP laminates to the tensile flanges of the welded box girder. Inspections carried out periodically on this structure revealed neither prestress losses nor crack initiation after nine years of service.

Hybrid knowledge expert tool for load capacity assessment of railway plate girders with defects

Science.gov (United States)

KuŻawa, M.; Bień, J.; Gładysz, M.

2013-10-01

Importance of the bridge structures as components of the transportation network is increasing and requires regular development of the management methodology. The main activities are focused on the safety of the users of the transportation network and on the safety of structures, based on monitoring and analysis of the bridge condition changes caused by various types of defects. The paper presents application of the hybrid network technology in the expert tool NOBLA supporting condition assessment of bridge plate girders, taking into account defects of the structures.

Parametric Study on Responses of a Self-Anchored Suspension Bridge to Sudden Breakage of a Hanger

Directory of Open Access Journals (Sweden)

Wenliang Qiu

2014-01-01

Full Text Available The girder of self-anchored suspension bridge is subjected to large compression force applied by main cables. So, serious damage of the girder due to breakage of hangers may cause the collapse of the whole bridge. With the time increasing, the hangers may break suddenly for their resistance capacities decrease due to corrosion. Using nonlinear static and dynamic analysis methods and adopting 3D finite element model, the responses of an actual self-anchored suspension bridge to sudden breakage of hangers are studied in this paper. The results show that the sudden breakage of a hanger causes violent vibration and large changes in internal forces of the bridge. In the process of the vibration, the maximum tension of hanger produced by breakage of a hanger exceeds 2.22 times its initial value, and the reaction forces of the bearings increase by more than 1.86 times the tension of the broken hanger. Based on the actual bridge, the influences of some factors including flexural stiffness of girder, torsion stiffness of girder, flexural stiffness of main cable, weight of girder, weight of main cable, span to sag ratio of main cable, distance of hangers, span length, and breakage time of hanger on the dynamic responses are studied in detail, and the influencing extent of the factors is presented.

Parametric study on responses of a self-anchored suspension bridge to sudden breakage of a hanger.

Science.gov (United States)

Qiu, Wenliang; Jiang, Meng; Huang, Cailiang

2014-01-01

The girder of self-anchored suspension bridge is subjected to large compression force applied by main cables. So, serious damage of the girder due to breakage of hangers may cause the collapse of the whole bridge. With the time increasing, the hangers may break suddenly for their resistance capacities decrease due to corrosion. Using nonlinear static and dynamic analysis methods and adopting 3D finite element model, the responses of an actual self-anchored suspension bridge to sudden breakage of hangers are studied in this paper. The results show that the sudden breakage of a hanger causes violent vibration and large changes in internal forces of the bridge. In the process of the vibration, the maximum tension of hanger produced by breakage of a hanger exceeds 2.22 times its initial value, and the reaction forces of the bearings increase by more than 1.86 times the tension of the broken hanger. Based on the actual bridge, the influences of some factors including flexural stiffness of girder, torsion stiffness of girder, flexural stiffness of main cable, weight of girder, weight of main cable, span to sag ratio of main cable, distance of hangers, span length, and breakage time of hanger on the dynamic responses are studied in detail, and the influencing extent of the factors is presented.

Practical assessment of magnetic methods for corrosion detection in an adjacent precast, prestressed concrete box-beam bridge

Science.gov (United States)

Fernandes, Bertrand; Titus, Michael; Nims, Douglas Karl; Ghorbanpoor, Al; Devabhaktuni, Vijay Kumar

2013-06-01

Magnetic methods are progressing in the detection of corrosion in prestressing strands in adjacent precast, prestressed concrete box-beam bridges. This study is the first field trial of magnetic strand defect detection systems on an adjacent box-beam bridge. A bridge in Fayette County, Ohio, which was scheduled for demolition, was inspected. Damage to prestressed box-beams is often due to corrosion of the prestressing strands. The corroded strands show discontinuities and a reduced cross-sectional area. These changes, due to corrosion, are reflected in the magnetic signatures of the prestressing steel. Corrosion in the prestressing steel was detected using two magnetic methods, namely the 'magnetic flux leakage' (MFL) and the 'induced magnetic field'. The purpose of these tests was to demonstrate the ability of the magnetic methods to detect hidden corrosion in box-beams in the field and tackle the logistic problem of inspecting box-beams from the bottom. The inspections were validated by dissecting the bottom of the box-beams after the inspections. The results showed that the MFL method can detect hidden corrosion and strand breaks. Both magnetic field methods were also able to estimate corrosion by detecting the effective cross-sectional area of the strand in sections of the beams. Thus, it was shown that the magnetic methods can be used to predict hidden corrosion in prestressing strands of box-beams.

Active Control of Long Bridges Using Flaps

DEFF Research Database (Denmark)

Hansen, H. I.; Thoft-Christensen, Palle

The main problem in designing ultra-long span suspension bridges is flutter. A solution to this problem might be to introduce an active flap control system to increase the flutter wind velocity. The investigated flap control system consists of flaps integrated in the bridge girder so each flap...... is the streamlined part of the edge of the girder. Additional aerodynamic derivatives are shown for the flaps and it is shown how methods already developed can be used to estimate the flutter wind velocity for a bridge section with flaps. As an example, the flutter wind velocity is calculated for different flap...... configurations for a bridge section model by using aerodynamic derivatives for a flat plate. The example shows that different flap configurations can either increase or decrease the flutter wind velocity. for optimal flap configurations flutter will not occur....

Aeroelastic Response from Indicial Functions with a Finite Element Model of a Suspension Bridge

Science.gov (United States)

Mikkelsen, O.; Jakobsen, J. B.

2017-12-01

The present paper describes a comprehensive analysis of the aeroelastic bridge response in time-domain, with a finite element model of the structure. The main focus is on the analysis of flutter instability, accounting for the wind forces generated by the bridge motion, including twisting as well as vertical and horizontal translation, i.e. all three global degrees of freedom. The solution is obtained by direct integration of the equations of motion for the bridge-wind system, with motion-dependent forces approximated from flutter derivatives in terms of rational functions. For the streamlined bridge box-girder investigated, the motion dependent wind forces related to the along-wind response are found to have a limited influence on the flutter velocity. The flutter mode shapes in the time-domain and the frequency domain are consistent, and composed of the three lowest symmetrical vertical modes coupled with the first torsional symmetric mode. The method applied in this study provides detailed response estimates and contributes to an increased understanding of the complex aeroelastic behaviour of long-span bridges.

Hybrid FRP-concrete bridge deck system final report II : long term performance of hybrid FRP-concrete bridge deck system.

Science.gov (United States)

2009-06-01

This report describes the investigation of the long term structural performance of a : hybrid FRP-concrete (HFRPC) bridge deck on steel girders. The study aimed at : assessing three long term aspects pertaining to the HFRPC bridge deck: (1) creep : c...

Design and construction of PC cable-stayed bridge reducing the weight of dead load (Minamitabaru No. 1 Bridge). Shuko danmen no keiryoka wo hakatta PC shachokyo (kasho Minamitabaru 1 go kyo)

Energy Technology Data Exchange (ETDEWEB)

Otsuka, H. (Building Research Inst., Tokyo (Japan)); Ikari, K.; Ono, Y. (Ministry of Construction, Tokyo (Japan)); Hirano, A.

1993-03-15

The Minamitabaru No.1 bridge is a PC cable-stayed bridge with a 170m center span. The cross section dead load weight of the main beam in the center span is reduced to decrease the unbalance moment during construction and the negative reaction force after the completion. As a result, the average volume of concrete in the center span becomes 0.55m[sup 3]/m[sup 2] which is less by about 20% in comparison with a PC cable-stayed bridge of the similar scale. Separated 2 chamber box girder cross section is adopted for the shape of the main beam cross section to reduce the dead load weight of the cross section, and to improve the rigidity of the cross section and wind resisting stability, etc. In addition, a cross beam is provided in the diagonal member anchorage position to integrate the two box beams. A wind tunnel test is performed using a 1/30 scale model to confirm the wind resisting stability. The diagonal member is structured with several PC steel members. At the same time, a stretching work carriage is developed and used which can establish 3 dimensional position and direction by a hydraulic jack. 7 figs.

Bridge and steel structures. History and vision on bridge erection; Kyoryo kokozobutsu. Kasetsu gijutsu no shorai

Energy Technology Data Exchange (ETDEWEB)

Mukai, S.; Hayashi, T. [Sumitomo Heavy Industries, Ltd., Tokyo (Japan)

1998-08-20

This paper describes the progress of bridge erection technology. It introduces the results of cable erection, rotated/extruded erection, and cantilever erection. The cable erection is a multi point suspension erection using cables. For the rotated/extruded erection, the monolithic construction is conducted on a working yard set in a right angle to the construction position, and the horizontal beams of the bridge piers (corbel girders) are constructed by the rotated method using a slewing base incorporated around the bridge piers at one side. For the construction of stiffening girders of Innoshima-ohashi Bridge of Honshu-Shikoku Joint Bridge in 1978, trussed face bar blocks were extruded from the main tower in order using a travel crane. For the suspension bridges and cable stayed bridges, main towers were erected using various types of cranes. The erection of Tamashima-ohashi Bridge with a weight of 500 ton using an offshore floating crane is introduced as a large block method. Analysis methods and measurement techniques at the site are used in order to analyze the shape in each step under the erection and to ensure the accurate final complete shape. Reduction of the construction cost, improvement of erection technology, and technology development for large-scale projects are subjects in the future. 22 refs., 8 figs., 1 tab.

Seismic fragility curves of bridge piers accounting for ground motions in Korea

Science.gov (United States)

Nguyen, Duy-Duan; Lee, Tae-Hyung

2018-04-01

Korea is located in a slight-to-moderate seismic zone. Nevertheless, several studies pointed that the peak earthquake magnitude in the region can be reached to approximately 6.5. Accordingly, a seismic vulnerability evaluation of the existing structures accounting for ground motions in Korea is momentous. The purpose of this paper is to develop seismic fragility curves for bridge piers of a steel box girder bridge equipped with and without base isolators based on a set of ground motions recorded in Korea. A finite element simulation platform, OpenSees, is utilized to perform nonlinear time history analyses of the bridges. A series of damage states is defined based on a damage index which is expressed in terms of the column displacement ductility ratio. The fragility curves based on Korean motions were thereafter compared with the fragility curves generated using worldwide earthquakes to assess the effect of the two ground motion groups on the seismic fragility curves of the bridge piers. The results reveal that both non- and base-isolated bridge piers are less vulnerable during the Korean ground motions than that under worldwide earthquakes.

Sadhana | Indian Academy of Sciences

Indian Academy of Sciences (India)

Bridges are one of the most crucial facilities of transportation networks. Therefore, evaluation of the seismic vulnerability of bridge structures is perpetually regarded topic for researchers. In this study, we developed seismic fragility curves for a continuous steel box girder bridge considering the effect of differentlevels of ...

Design Optimization of Hybrid FRP/RC Bridge

Science.gov (United States)

Papapetrou, Vasileios S.; Tamijani, Ali Y.; Brown, Jeff; Kim, Daewon

2018-04-01

The hybrid bridge consists of a Reinforced Concrete (RC) slab supported by U-shaped Fiber Reinforced Polymer (FRP) girders. Previous studies on similar hybrid bridges constructed in the United States and Europe seem to substantiate these hybrid designs for lightweight, high strength, and durable highway bridge construction. In the current study, computational and optimization analyses were carried out to investigate six composite material systems consisting of E-glass and carbon fibers. Optimization constraints are determined by stress, deflection and manufacturing requirements. Finite Element Analysis (FEA) and optimization software were utilized, and a framework was developed to run the complete analyses in an automated fashion. Prior to that, FEA validation of previous studies on similar U-shaped FRP girders that were constructed in Poland and Texas is presented. A finer optimization analysis is performed for the case of the Texas hybrid bridge. The optimization outcome of the hybrid FRP/RC bridge shows the appropriate composite material selection and cross-section geometry that satisfies all the applicable Limit States (LS) and, at the same time, results in the lightest design. Critical limit states show that shear stress criteria determine the optimum design for bridge spans less than 15.24 m and deflection criteria controls for longer spans. Increased side wall thickness can reduce maximum observed shear stresses, but leads to a high weight penalty. A taller cross-section and a thicker girder base can efficiently lower the observed deflections and normal stresses. Finally, substantial weight savings can be achieved by the optimization framework if base and side-wall thickness are treated as independent variables.

Fatigue of cable anchorage of large cable stayed bridge; Daikibo shachokyo cable teichaku kozo no hiro

Energy Technology Data Exchange (ETDEWEB)

Endo, T.; Matsumoto, T. [Honshu-Shikoku Bridge Authority, Tokyo (Japan); Tsukahara, H. [Yokogawa Bridge Corp., Tokyo (Japan); Miki, C. [Tokyo Institute of Technology, Tokyo (Japan)

1995-10-21

Design considerations such as design schemes, the assemblage and welding of steel plates, and safety for fatigue of welded connections have to be taken for the cable anchorages of the steel cable stayed bridges. In this study, two full scale models, which have different shape of box anchorages welded to the web of the main girder, were made to investigate fatigue characteristics as well as assemblage of plate and gelding details. Finite element analyses for both test models and actual bridges here carried out to compare stress distribution. It was confirmed that the assemblage and welding of both types of box anchorage were attainable kith required quality and accuracy. According to the fatigue test, fatigue cracks originated from the weldings of the bearing plate to which the load from cable socket applied directly were caused by out-of-plane bending of the bearing plate. It was proved that the slight modifications of the details around the bearing plate resulted in sufficient fatigue strength in both types of anchorage. 1 ref., 23 figs., 2 tabs.

Analysis of Biaxially Stressed Bridge Deck Plates

DEFF Research Database (Denmark)

Jönsson, Jeppe; Bondum, Tommi Højer

2012-01-01

The ultimate state analysis of bridge deck plates at the intersection zone between main girders and transverse beams is complicated by biaxial membrane stresses, which may be in compression or tension in either direction depending on the bridge configuration and the specific location. This paper...

Fatigue Testing of Maglev-Hybrid Box Beam

Science.gov (United States)

2009-03-02

04142009 3. DATES COVERED: (From - To) 23052006-14092008 4. TITLE AND SUBTITLE Fatigue Testing of Maglev -Hybrid Box Beam 5a. CONTRACT NUMBER NA...was previously built under collaboration between Maglev Inc. and Lehigh University. The girder was instrumented with strain gages and LVDT’s to monitor...report March 2,2009 Contract N00014-06-1-0872 Project: Fatigue Testing of Maglev -Hybrid Box Beam Prepared by Dr. J.L. Grenestedt and Dr. R. Sause

A Comparative Assessment of Aerodynamic Models for Buffeting and Flutter of Long-Span Bridges

Directory of Open Access Journals (Sweden)

Igor Kavrakov

2017-12-01

Full Text Available Wind-induced vibrations commonly represent the leading criterion in the design of long-span bridges. The aerodynamic forces in bridge aerodynamics are mainly based on the quasi-steady and linear unsteady theory. This paper aims to investigate different formulations of self-excited and buffeting forces in the time domain by comparing the dynamic response of a multi-span cable-stayed bridge during the critical erection condition. The bridge is selected to represent a typical reference object with a bluff concrete box girder for large river crossings. The models are viewed from a perspective of model complexity, comparing the influence of the aerodynamic properties implied in the aerodynamic models, such as aerodynamic damping and stiffness, fluid memory in the buffeting and self-excited forces, aerodynamic nonlinearity, and aerodynamic coupling on the bridge response. The selected models are studied for a wind-speed range that is typical for the construction stage for two levels of turbulence intensity. Furthermore, a simplified method for the computation of buffeting forces including the aerodynamic admittance is presented, in which rational approximation is avoided. The critical flutter velocities are also compared for the selected models under laminar flow. Keywords: Buffeting, Flutter, Long-span bridges, Bridge aerodynamics, Bridge aeroelasticity, Erection stage

Determination of brace forces caused by construction loads and wind loads during bridge construction : [summary].

Science.gov (United States)

2014-04-01

Bridges are constructed in stages as pilings, : columns, girders, decks, and other components : are added. At each stage, the structure must be : stable. Girders, which add significant weight to : the developing structure, rest on elastomeric : beari...

Wind Turbine Blade with Angled Girders

DEFF Research Database (Denmark)

2011-01-01

The present invention relates to a reinforced blade for a wind turbine, particularly to a blade having a new arrangement of two or more girders in the blade, wherein each of the girders is connected to the upper part and the lower part of the shell and forms an angle with another girder thereby...

Design and test of a girder control system at NSRRC

International Nuclear Information System (INIS)

Wang, H.S.; Tsai, Y.L.; Perng, S.Y.; Chen, M.L.; Hsu, K.H.; Lai, W.Y.; Tseng, T.C.; Chen, J.R.

2012-01-01

A girder control system is proposed to quickly and precisely adjust the displacement and rotating angle of all girders in the storage ring with little manpower at the Taiwan Photon Source (TPS) project at National Synchrotron Research Center (NSRRC). In this control girder system, six motorized cam movers supporting a girder are driven on three pedestals to perform six-axis adjustments of a girder. A tilt-meter monitors the pitch and roll of each girder; several touch sensors measure the relative displacement between consecutive girders. Moreover, a laser position sensitive detector (PSD) system measuring the relative displacement between straight-section girders is included in this girder control system. Operator can use subroutines developed by MATLAB to control every local girder control system via the web. The test results show that the girder control system adjusts girders quickly, precisely and stably

An influence of technological contraflexure of crane bridges on its durability

Directory of Open Access Journals (Sweden)

Artur BLUM

2010-01-01

Full Text Available Standard requirements till 1996 year during bridge crane manufacturing demanded a positive technological contraflexure. As a result of this process were implemented technological compressive stress into tensile zone from inertial and operational loads and tensile stress into compressive zone. This way there were redistributed resultant stress which have increased fatigue strength of exploited crane bridges. Actually valid standard PN-ISO 7363 has removed this obligatory requirement. Its use depends of crane buyer demands. Reduction of initial positive deflection can be seen after few years of crane operations. It is a case of girders permanent deflections increment. Article presents method of technological prestressing of bridge girders with its practical application to obtain positive contrafexure.

Deflection control system for prestressed concrete bridges by CCD camera. CCD camera ni yoru prestressed concrete kyo no tawami kanri system

Energy Technology Data Exchange (ETDEWEB)

Noda, Y.; Nakayama, Y.; Arai, T. (Kawada Construction Co. Ltd., Tokyo (Japan))

1994-03-15

For the long-span prestressed concrete bridge (continuous box girder and cable stayed bridge), the design and construction control becomes increasingly complicated as construction proceeds because of its cyclic works. This paper describes the method and operation of an automatic levelling module using CCD camera and the experimental results by this system. For this automatic levelling system, the altitude can be automatically measured by measuring the center location of gravity of the target on the bridge surface using CCD camera. The present deflection control system developed compares the measured value by the automatic levelling system with the design value obtained by the design calculation system, and manages them. From the real-time continuous measurement for the long term, in which the CCD camera was set on the bridge surface, it was found that the stable measurement accuracy can be obtained. Successful application of this system demonstrates that the system is an effective and efficient construction aid. 11 refs., 19 figs., 1 tab.

FE-ANN based modeling of 3D Simple Reinforced Concrete Girders for Objective Structural Health Evaluation : Tech Transfer Summary

Science.gov (United States)

2017-06-01

The objective of this study was to develop an objective, quantitative method for evaluating damage to bridge girders by using artificial neural networks (ANNs). This evaluation method, which is a supplement to visual inspection, requires only the res...

Assessing the need for intermediate diaphragms in prestressed concrete bridges.

Science.gov (United States)

2008-03-01

Reinforced concrete intermediate diaphragms (IDs) are currently being used in prestressed concrete (PC) girder bridges in Louisiana. Some of the advantages of providing IDs are disputed in the bridge community; the use of IDs increases the cost and t...

Application of Composite Structures in Bridge Engineering. Problems of Construction Process and Strength Analysis

Science.gov (United States)

Flaga, Kazimierz; Furtak, Kazimierz

2015-03-01

Steel-concrete composite structures have been used in bridge engineering from decades. This is due to rational utilisation of the strength properties of the two materials. At the same time, the reinforced concrete (or prestressed) deck slab is more favourable than the orthotropic steel plate used in steel bridges (higher mass, better vibration damping, longer life). The most commonly found in practice are composite girder bridges, particularly in highway bridges of small and medium spans, but the spans may reach over 200 m. In larger spans steel truss girders are applied. Bridge composite structures are also employed in cable-stayed bridge decks of the main girder spans of the order of 600, 800 m. The aim of the article is to present the cionstruction process and strength analysis problems concerning of this type of structures. Much attention is paid to the design and calculation of the shear connectors characteristic for the discussed objects. The authors focused mainly on the issues of single composite structures. The effect of assembly states on the stresses and strains in composite members are highlighted. A separate part of problems is devoted to the influence of rheological factors, i.e. concrete shrinkage and creep, as well as thermal factors on the stresses and strains and redistribution of internal forces.

Application of Classical Land Surveying Measurement Methods for Determining the Vertical Displacement of Railway Bridges

Science.gov (United States)

Gawronek, Pelagia; Makuch, Maria

2017-12-01

The classical measurements of stability of railway bridge, in the context of determining the vertical displacements of the object, consisted on precise leveling of girders and trigonometric leveling of controlled points (fixed into girders' surface). The construction elements, which were measured in two ways, in real terms belonged to the same vertical planes. Altitude measurements of construction were carried out during periodic structural stability tests and during static load tests of bridge by train. The specificity of displacement measurements, the type of measured object and the rail land surveying measurement conditions were determinants to define methodology of altitude measurement. The article presents compatibility of vertical displacements of steel railway bridge, which were developed in two measurement methods. In conclusion, the authors proposed the optimum concept of determining the vertical displacements of girders by using precise and trigonometric leveling (in terms of accuracy, safety and economy of measurement).

Application of Classical Land Surveying Measurement Methods for Determining the Vertical Displacement of Railway Bridges

Directory of Open Access Journals (Sweden)

Gawronek Pelagia

2017-12-01

Full Text Available The classical measurements of stability of railway bridge, in the context of determining the vertical displacements of the object, consisted on precise leveling of girders and trigonometric leveling of controlled points (fixed into girders' surface. The construction elements, which were measured in two ways, in real terms belonged to the same vertical planes. Altitude measurements of construction were carried out during periodic structural stability tests and during static load tests of bridge by train. The specificity of displacement measurements, the type of measured object and the rail land surveying measurement conditions were determinants to define methodology of altitude measurement. The article presents compatibility of vertical displacements of steel railway bridge, which were developed in two measurement methods. In conclusion, the authors proposed the optimum concept of determining the vertical displacements of girders by using precise and trigonometric leveling (in terms of accuracy, safety and economy of measurement.

A technical report on structural evaluation of the Meade County reinforced concrete bridge : research [summary].

Science.gov (United States)

2009-01-01

Meade County Bridge is a two-lane highway reinforced concrete bridge with two girders each with 20 continuous spans. The bridge was built in 1965. It has been reported that in early years of the bridge service period, a considerable amount of cracks ...

Yonjung High-Speed Railway Bridge Assessment Using Output-Only Structural Health Monitoring Measurements under Train Speed Changing

Directory of Open Access Journals (Sweden)

Mosbeh R. Kaloop

2016-01-01

Full Text Available Yonjung Bridge is a hybrid multispan bridge that is designed to transport high-speed trains (HEMU-430X with maximum operating speed of 430 km/h. The bridge consists of simply supported prestressed concrete (PSC and composite steel girders to carry double railway tracks. The structural health monitoring system (SHM is designed and installed to investigate and assess the performance of the bridge in terms of acceleration and deformation measurements under different speeds of the passing train. The SHM measurements are investigated in both time and frequency domains; in addition, several identification models are examined to assess the performance of the bridge. The drawn conclusions show that the maximum deflection and acceleration of the bridge are within the design limits that are specified by the Korean and European codes. The parameters evaluation of the model identification depicts the quasistatic and dynamic deformations of PSC and steel girders to be different and less correlated when higher speeds of the passing trains are considered. Finally, the variation of the frequency content of the dynamic deformations of the girders is negligible when high speeds are considered.

Performance of self-consolidating concrete in prestressed girders.

Science.gov (United States)

2010-04-01

A structural investigation of self-consolidating concrete (SCC) in AASHTO Type I precast, : prestressed girders was performed. Six test girders were subjected to transfer length and : flexural testing. Three separate concrete mixtures, two girders pe...

Design and construction of the Natorigawa Bridge; Natorigawa kyoryo no sekkei/seko

Energy Technology Data Exchange (ETDEWEB)

Murai, Y.; Oba, M.; Omurata, Y. [JR East Japan Railway Co., Tokyo (Japan); Miyauchi, M.; Iwasaki, I. [Taisei Corp., Tokyo (Japan)

1997-03-31

The Natorigawa Bridge is reconstructed. Out of the reconstruction work, a report is made mainly on the design of the superstructure work of the PC panel-stayed bridge and the details of the work. In selecting bridge type, PC simple through beam bridge, steel trussed bridge, PC cable-stayed bridge, and PC panel-stayed bridge are compared, and a 2-span continuous PC panel-stayed bridge is adopted. Its appearance resembles that of the cable-stayed bridge, but the structure resembles a girder bridge. The appropriate span length is the intermediate range between those of the girder bridge and the cable-stayed bridge. Its trafficability is excellent with little deformation by the running of trains because the main beam, diagonal panel, and the main tower are connected rigidly to provide high rigidity of the entire bridge. PRC structure is employed in consideration of the restriction to beam height and economical efficiency. Analyses by a FEM model using two dimensional plane elements and by a few plane frame models as well as comparison of sectional force are performed for this bridge, and a proper plane model is selected. Substructure work, superstructure work and measurement work are described. 3 refs., 16 figs., 6 tabs.

Critical traffic loading for the design of prestressed concrete bridge

International Nuclear Information System (INIS)

Hassan, M.I.U.

2009-01-01

A study has been carried out to determine critical traffic loadings for the design of bridge superstructures. The prestressed concrete girder bridge already constructed in Lahore is selected for the analysis as an example. Standard traffic loadings according to AASHTO (American Association of State Highway and Transportation Officials) and Pakistan Highway Standards are used for this purpose. These include (1) HL-93 Truck, (2) Lane and (3) Tandem Loadings in addition to (4) Military tank loading, (5) Class-A, (6) Class-B and (7) Class-AA loading, (8) NLC (National Logistic Cell) and (9) Volvo truck loadings. Bridge superstructure including transom beam is analyzed Using ASD and LRFD (Load and Resistance Factor Design) provisions of AASHTO specifications. For the analysis, two longer and shorter spans are selected. This includes the analysis of bridge deck; interior and exterior girder; a typical transom beam and a pier. Dead and live loading determination is carried out using both computer aided and manual calculations. Evaluation of traffic loadings is done for all the bridge components to find out the critical loading. HL-93 loading comes out to be the most critical loading and where this loading is not critical in case of bridge decks; a factor of 1.15 is introduced to make it equivalent with HL-93 -Ioading. SAP-2000 (Structural Engineering Services of Pakistan) and MS-Excel is employed for analysis of bridge superstructure subjected to this loading. Internal forces are obtained for the structural elements of the bridge for all traffic loadings mentioned. It is concluded that HL-93 loading can be used for the design of prestressed concrete girder bridge. Bridge design authorities like NHA (National Highway Authority) and different cities development authorities are using different standard traffic loadings. A number of suggestions are made from the results of the research work related to traffic loadings and method of design. These recommendations may be

Ultimate strength analysis of long-span cable-stayed bridges; Chodai chachokyo no shukyoku kyodo kaiseki to kyodo ni kansuru ichikosatsu

Energy Technology Data Exchange (ETDEWEB)

Xie, X.; Yamaguchi, H. [Saitama Univ., Urawa (Japan)] Nagai, M. [Nagaoka Technical Coll., Niigata (Japan)

1998-07-21

Recently, span of cable-stayed bridges has been getting loner and longer, present situation is that cable-stayed bridges with span 600 to 800m class have been built inside and outside the country, and accurate determination of its ultimate strength has been an important problem statistically. However, concrete design method for evaluating load bearing stress of long-span cable-stayed bridge. Particularly of the main beam whose axial stress is dominating, has not been established so far. As for cable-stayed bridge, even for long-span, effect of plasticization of cross section on ultimate strength is severe because there is little effect of geometric nonlinearity and it is thought that accurate evaluation of ultimate strength only by elastic finite potential analysis is difficult. Accordingly, it is necessary to study the behavior by using combined nonlinear analysis considering the nonlinearity of the material in order to evaluate the safety and economy to long-span cable-stayed bridge. In this report, 3 dimensional analysis method was formularized taking into account the combine nonlinearity of multi-box girder and analysis program of ultimate strength behavior of long-span cable-stayed bridge was developed. 19 refs., 17 figs., 2 tabs.

Cable-stayed PC bridge with inclined main tower. Hachinohe port island bridge; Keisha shuto to yusuru 2 keikan renzoku PC shachokyo. Hachinoheko port island renrakykyo (kasho)

Energy Technology Data Exchange (ETDEWEB)

Hasegawa, A. [Hachinohe Institute of Technology, Aomori (Japan)

1994-09-15

The design and construction of the inclined main bridge, which is being constructed at the mouth of the Hachinohe Harbor (in Japan), are outlined in this paper. This connecting bridge has an overall length of 265.56 m, and consists of the main bridge member of asymmetric 2 cable-stayed PC bridge and the 3 cable-stayed PC box member bridge. An asymmetric design was employed for the main bridge frame to ensure the access space for small ships passing between bridge girders, easy maintenance and service, improved economy, and excellent view. The main tower is a single-pillar reinforced concrete structure with an inclination of 15{degree} and 47 m in height. Forty-eight diagonal cables are arranged so that 12 cable trains are connected to the main tower on the right and left sides respectively, and the back-stay cable structure is used for each upper 3 cable trains to improve safety against the earthquake. The main beam is made by a prestressed concrete structure with inverse trapezoidal 3-chamber frame section. This structure is superior in increasing the safety against wind. Steel tube sheet-pile well is selected for the bridge pier base, and debris layer is selected as a support layer for the base. For the construction of the lower bridge section, sand conversion through predrilling of rubble-mound and debris layer was executed. The underwater non-separative concrete and embedded type frame are used around the bridge piers and its surrounding. For the construction of the upper bridge section, steel frames are used inside the main tower to ensure the construction precision. 7 figs.

Design of Usui bridge (PC cable stayed bridge). Usuihashi (PC shachokyo) no sekkei ni tsuite

Energy Technology Data Exchange (ETDEWEB)

Kido, M.; Iizuka, Y. (Japan Highway Public Corp., Tokyo (Japan)); Tanaka, S.; Otsuka, K. (P.S. Concrete Co. Ltd. Kajima Corp. Joint Venture, Tokyo (Japan)); Kitakuni, S. (Kajima Corp., Tokyo (Japan))

1991-11-30

Structure and design of single suspension PC cable bridge, which is first kind of high way bridge in Japan and aiming to start for general use by March, 1993, are reported. As a construction outline, main construction quantity and general layout of the whole bridge together with the selective detail and characteristics of the diagonal member, tower, main girder and tower support member, are cited. Design conditions( load, materials, allowable stress and others ), basic plan of the design, and structure analysis( surface stress framed structure analysis, stereoscopic framework analysis and FEM analysis of local stress ) are explained. Design of structure member like main girder is based on diagonal member tension, wave shearing force, level of diagonal strain stress, bending stress when diagonal member anchors the deformed main tower caused by living load during earth quake, principal stress of main tower junction and local stress etc. Main tower support member design is based on the results of corbel shearing force at varied cross section and main stress, and diagonal member design is decided by allowable stress. Diagonal member anchorage traverse beam design depends on bending moment of traverse beam and shearing force. 3 refs., 15 figs., 1 tab.

Dynamic response of the train-track-bridge system subjected to derailment impacts

Science.gov (United States)

Ling, Liang; Dhanasekar, Manicka; Thambiratnam, David P.

2018-04-01

Derailments on bridges, although not frequent, when occurs due to a complex dynamic interaction of the train-track-bridge structural system, are very severe. Furthermore, the forced vibration induced by the post-derailment impacts can toss out the derailed wagons from the bridge deck with severe consequences to the traffic underneath and the safety of the occupants of the wagons. This paper presents a study of the train-track-bridge interaction during a heavy freight train crossing a concrete box girder bridge from a normal operation to a derailed state. A numerical model that considers the bridge vibration, train-track interaction and the train post-derailment behaviour is formulated based on a coupled finite-element - multi-body dynamics (FE-MBD) theory. The model is applied to predict the post-derailment behaviour of a freight train composed of one locomotive and several wagons, as well as the dynamic response of a straight single-span simply supported bridge containing ballast track subjected to derailment impacts. For this purpose, a typical derailment scenario of a heavy freight train passing over a severe track geometry defect is introduced. The dynamic derailment behaviour of the heavy freight train and the dynamic responses of the rail bridge are illustrated through numerical examples. The results exhibit the potential for tossing out of the derailed trains from the unstable increase in the yaw angle signature and a lower rate of increase of the bridge deck bending moment compared to the increase in the static axle load of the derailed wheelset.

Study on load test of 100m cross-reinforced deck type concrete box arch bridge

Science.gov (United States)

Shi, Jing Xian; Cheng, Ying Jie

2018-06-01

Found in the routine quality inspection of highway bridge that many vertical fractures on the main beam (10mT beam) of the steel reinforced concrete arch bridge near the hydropower station. In order to grasp the bearing capacity of this bridge under working conditions with cracks, the static load and dynamic load test of box arch bridge are carried out. The Midas civil theory is calculated by using the special plate trailer - 300 as the calculation load, and the deflection and stress of the critical section are tested by the equivalent cloth load in the test vehicle. The pulsation test, obstacles and no obstacle driving test were carried out. Experimental results show that the bridge under the condition of the test loads is in safe condition, main bearing component of the strength and stiffness meet the design requirements, the crack width does not increase, in the process of loading bridge overall work performance is good.

Cable-stayed bridge No. 1 Hikihara bridge'' ( Karauko bridge'') for Kinki construction bureau, ministry of construction. Kensetsusho kinki chiho kensetsukyoku (Hikihara 1 gobashi (Karauko ohashi))no shiko

Energy Technology Data Exchange (ETDEWEB)

1991-11-01

This paper summarizes the design, fabrication and erection of a back-anchor integrated single span cable suspension bridge (178 m long and 9.7 m wide) constructed over an ordinary road crossing a reservoir. This type of structure was adopted because the locational condition does not allow a bridge pier to be erected in the center of the pond, and the topography in the construction starting side has steep slopes and many places having fragile ground beds. This bridge employed precast floor plates using the Compo-Slab (manufactured by Ishikawajima Building Material Company). Main points which require attentions are listed in designing and fabricating the main towers (48 m high), main girders, and cables, as well as fabricating the precast cast floor plates (a panel has a length of 9.7 m, maximum width of 2 m, and maximum weight of 10 tons). The main towers were erected using 160-tf truck cranes, and the main girders were erected by the overhang method using 20-tf gate-type travel cranes. 3 refs., 14 figs.

Wireless Impedance Sensor with PZT-Interface for Prestress-Loss Monitoring in Prestressed Concrete Girder

International Nuclear Information System (INIS)

Nguyen, Khac Duy; Lee, So Young; Kim, Jeong Tae

2011-01-01

Ensuring the designed prestress force is very important for the safety of prestressed concrete bridge. The loss of prestress force in tendon could significantly reduce load carrying capacity of the structure. In this study, an automated prestress-loss monitoring system for prestressed concrete girder using PZT-interface and wireless impedance sensor node is presented. The following approaches are carried out to achieve the objective. Firstly, wireless impedance sensor nodes are designed for automated impedance-based monitoring technique. The sensor node is mounted on the high-performance Imote2 sensor platform to fulfill high operating speed, low power requirement and large storage memory. Secondly, a smart PZT-interface designed for monitoring prestress force is described. A linear regression model is established to predict prestress-loss. Finally, a system of the PZT-interface interacted with the wireless sensor node is evaluated from a lab-scale tendon-anchorage connection of a prestressed concrete girder

Detection of insulation flaws and thermal bridges in insulated truck box panels

OpenAIRE

Lei, Lei; Bortolin, Alessandro; Bison, Paolo ©; Maldague, X.

2017-01-01

This paper focuses on the detection of defects and thermal bridges in insulated truck box panels, utilising infrared thermography. Unlike the traditional way in which passive thermography is applied, this research uses both heating and cooling methods in active thermography configurations. Lamp heating is used as the hot external stimulation, while a compressed air jet is applied as the cold external stimulation. A thermal camera captures the whole process. In addition, numerical simulations ...

Research on Collapse Process of Cable-Stayed Bridges under Strong Seismic Excitations

Directory of Open Access Journals (Sweden)

Xuewei Wang

2017-01-01

Full Text Available In order to present the collapse process and failure mechanism of long-span cable-stayed bridges under strong seismic excitations, a rail-cum-road steel truss cable-stayed bridge was selected as engineering background, the collapse failure numerical model of the cable-stayed bridge was established based on the explicit dynamic finite element method (FEM, and the whole collapse process of the cable-stayed bridge was analyzed and studied with three different seismic waves acted in the horizontal longitudinal direction, respectively. It can be found from the numerical simulation analysis that the whole collapse failure process and failure modes of the cable-stayed bridge under three different seismic waves are similar. Furthermore, the piers and the main pylons are critical components contributing to the collapse of the cable-stayed bridge structure. However, the cables and the main girder are damaged owing to the failure of piers and main pylons during the whole structure collapse process, so the failure of cable and main girder components is not the main reason for the collapse of cable-stayed bridge. The analysis results can provide theoretical basis for collapse resistance design and the determination of critical damage components of long-span highway and railway cable-stayed bridges in the research of seismic vulnerability analysis.

Erection of the Meiko-Central bridge; Meiko chuo ohashi no kasetsu

Energy Technology Data Exchange (ETDEWEB)

Kaneda, S.; Nishikawa, K.; Nagai, Y.; Ishihara, S.; Tsunekawa, M.; Yoshino, S. [Kawasaki Heavy Industries, Ltd., Kobe (Japan)

1997-10-20

This is a 1170m-long triple-span continuous steel cable-stayed bridge with the central span measuring 590m, built to traverse Nagoya Port as part of the Isewangan highway. The 190m-high main towers are A-shaped, and have an octagonal cross section to stay stable against winds. The joints were designed to be welded mainly on the spot so as not to affect the surrounding landscape, and in this welding process the achievement of prescribed accuracy was the important technological task. The main girder was a 37m-wide multi-chamber/single-box type, and the steel stabs were installed by on-site welding. Since the erection was carried out above the ship course, a method was used in which the main girder was hung over with the cable stretched long, which demanded constant prudence to assure accuracy throughout the work. The cable is a 17-stage 2-face multi-fan type, a semi-parallel wire strand coated with polyethylene and white fluoroethylene resin. As for accuracy management for erection, it was accomplished by adjusting the amount of shim introduced into each of the four cables every time one stage of cable was erected for the side span and central span. Every accuracy management requirement met the target value with an adequate margin. 6 refs., 10 figs., 4 tabs.

Effect of Piers Shape on the Dynamic Structural Responses of Prestressed Concrete Bridge: Part II

Directory of Open Access Journals (Sweden)

Ali Fadhil Naser

2016-03-01

Full Text Available Pier of bridge is usually used as a general term for any type of substructure located between horizontal spans and foundations. Piers give vertical supports for spans at intermediate points and perform two main functions. The objective of this study is to inspect the effect of piers shape on the dynamic structural performance by adopting theoretical dynamic analysis. The results of dynamic analysis of 25 bridges models show that the maximum value of natural frequency is equal to 5.64Hz in two circles piers bridge model. Therefore, this type of model has good stiffness and bearing capacity. The two square piers model, the one circle pier model, and the two circles piers model appear good stiffness because of the natural frequencies (5.30Hz, 5.52Hz, and 5.64Hz are more than the maximum forced frequencies (4.52Hz, 5.45Hz, and 4.52Hz respectively. According to the comparison between all models results, the two circles piers model has the higher stiffness because of this model has the maximum value of natural frequency (5.64Hz and it is more than all forced vibration frequencies of all others models. Therefore, this study recommends that using the bridge model of two circles piers in the bridges construction that consists of three spans (30m+40m+30m with section of box girder.

Effect of Piers Shape on the Dynamic Structural Responses of Prestressed Concrete Bridge: Part II

Directory of Open Access Journals (Sweden)

Ali Fadhil Naser

2016-12-01

Full Text Available Pier of bridge is usually used as a general term for any type of substructure located between horizontal spans and foundations. Piers give vertical supports for spans at intermediate points and perform two main functions. The objective of this study is to inspect the effect of piers shape on the dynamic structural performance by adopting theoretical dynamic analysis. The results of dynamic analysis of 25 bridges models show that the maximum value of natural frequency is equal to 5.64Hz in two circles piers bridge model. Therefore, this type of model has good stiffness and bearing capacity. The two square piers model, the one circle pier model, and the two circles piers model appear good stiffness because of the natural frequencies (5.30Hz, 5.52Hz, and 5.64Hz are more than the maximum forced frequencies (4.52Hz, 5.45Hz, and 4.52Hz respectively. According to the comparison between all models results, the two circles piers model has the higher stiffness because of this model has the maximum value of natural frequency (5.64Hz and it is more than all forced vibration frequencies of all others models. Therefore, this study recommends that using the bridge model of two circles piers in the bridges construction that consists of three spans (30m+40m+30m with section of box girder.

Construction of cable-stayed prestressed concrete bridge, having Japan`s first independent single slanted tower; Nippon hatsu no keisha shuto wo motsu PC shachokyo no seko

Energy Technology Data Exchange (ETDEWEB)

Sanada, Y.; Naito, H. [Penta-Ocean Construction Co. Ltd., Tokyo (Japan); Takeuchi, H.; Mikami, T.

1994-08-01

In the Hachinoe Harbor, Aomori prefecture, a man-made island (Hachinoe Port Island) is being constructed by reclamation. When proceeding this undertaking plan, a construction of the Hachinoe Harbor Port Island connection bridge, which connects the man-made island with the existing harbor district, was made an urgent necessity. This connecting bridge is a bridge with a total length of 256.56m, and is constituted of two span continuous PC slanted bridge and three span continuous PC box girder bridge. This slanted bridge has become an asymmetrical structure due to several conditions coming from a plan, and moreover it has the first structural shape as a road bridge in Japan, of which main tower is 15{degree} slanted independent single tower type, there are more problems for the work execution compared with other normal slanted bridges. In addition, because it is situated in an extremely cruel environment like in the cold region and in the marine environment, a sufficient consideration is required for its design and work execution in order to insure a durability. In this report, an outline of work execution content about PC slanted bridge part currently under a construction zealously aiming at a completion in the end of the fiscal year 1994 is introduced. 2 refs., 14 figs., 4 tabs.

Chichibu park bridge, a Japan's longest PC cable suspension bridge that attaches importance to scenery. Keikan wo jushishita Nippon saidai no PC shachokyo 'Chichibu koenkyo'

Energy Technology Data Exchange (ETDEWEB)

1993-12-01

This paper introduces the feature of Chichibu Park Bridge, a Japan's longest PC cable suspension bridge that attaches importance to scenery. The maximum effective span of Chichibu Park Bridge which is a two-span continuous PC cable suspension bridge measures 195 m, that means the center span length is equivalent to about 400 m if converted to a three-span structure. With respect to the design that values the scenic effect, the main tower has relief engravings of stone carving tone using Chichibu Night Festival as a motif disposed around it; lighting up is applied to the main tower to highlight it so that it can be viewed from far away places; and a balcony is built on the center of the bridge. Chichibu Park Bridge has the bridge axial direction stagger with the river flow direction at 45[degree] to reduce water resistance. The tensile force generated at the corbel section according to the main tower reactive force is dealt with reinforced concrete rather than with prestressed concrete. The main tower adopts a two-chamber girder structure as its cross section shape from the view points of rigidity assurance and scenic effect. For construction control, micro computers are used to correct growing change in bend of the main girder due to temperature change and cable tension change. 6 figs., 4 tabs.

Solid Modeling and Finite Element Analysis of an Overhead Crane Bridge

Directory of Open Access Journals (Sweden)

C. Alkin

2005-01-01

Full Text Available The design of an overhead crane bridge with a double box girder has been investigated and a case study of a crane with 35 ton capacity and 13 m span length has been conducted. In the initial phase of the case study, conventional design calculations proposed by F. E. M. Rules and DIN standards were performed to verify the stress and deflection levels. The crane design was modeled using both solids and surfaces. Finite element meshes with 4-node tetrahedral and 4-node quadrilateral shell elements were generated from the solid and shell models, respectively. After a comparison of the finite element analyses, the conventional calculations and performance of the existing crane, the analysis with quadratic shell elements was found to give the most realistic results. As a result of this study, a design optimization method for an overhead crane is proposed. 

Investigation of aerodynamic stability by wind response observation during cantilever construction of the Ikara Ohashi bridge; Ikara Ohashi haridashi sekoji no kaze kansoku ni yoru taifu anteisei no kento

Energy Technology Data Exchange (ETDEWEB)

Ueno, K.; Mukai, H.; Takeda, T. [Kajima Corp., Tokyo (Japan)

1995-12-20

In order to ensure aerodynamic stability during cantilever construction of the Ikara Ohashi Bridge, wind response observation was carried out and discussions were given on the result. The Ikara Ohashi Bridge is a 5-span continuous PC cable-stayed bridge with the central span being a concrete bridge having a length of 260 m, which is the longest in Japan. The bridge was constructed using a method that main girders are extended from the central tower to the right and left sides while the girders are stayed by bracing cables. The bridge construction site is in an area which is often subjected to typhoons and gusts like seasonal winds in winter, hence a discussion on aerodynamic stability of the bridge especially during extension work was viewed as an important matter. In addition, the construction used two small-capacity cables spaced and bundled as the bracing material, which required verification on their aerodynamic stability. In order to identify vibration characteristics of the main girders and the central tower, wind response observation has been performed as soon as the construction was begun. As a result, the vibration characteristics of the main girders and the central tower were identified, and it was verified that vibration shape and dominant frequency can be evaluated properly by an intrinsic value analysis that uses a multi-material point frame model. Furthermore, effects of different vibration absorbing measures were compared, and the effective methods were adopted as the result. 4 refs., 12 figs.

Fabrication and erection of 'Chuo ohashi bridge' for Tokyo Metropolitan Government. Tokyoto kensetsukyoku 'Chuo ohashi' no seisaku oyobi kasetsu

Energy Technology Data Exchange (ETDEWEB)

1994-07-01

The present report outlines the superstructure of 'Chuo Ohashi Bridge' spanning the Sumida River, Tokyo Metropolis. Being 210.7m in length and 25.0m in breadth, that bridge is a cable-stayed bridge partially curved with a 220m radius curvature. Having a height of 76.8m, its main tower is shaped into an upside-down V with a curved top. Description of the points of which care was specially taken for the fabrication and construction in yard covers the cable anchorage of both girders and tower, assembly and welding, anti-shrinkage camber of girders, weld bevel preparation for the tower, tentative assembly, and accuracy control. Results of the wind tunnel test with a (1/50) scale model are as follows: stay cables were installed as measures against the vibration during the main tower erection. The main girders, main tower and cables were the order of superstructural erection. The cable tensioning was supervised mainly with its proper tension adjustment and subsidiarily for the configuration of bridge built. 2 refs., 10 figs., 1 tab.

Static behaviors of long-span cable-stayed bridge; Chodai shachokyo no seiteki kyodo ni kansuru kosatsu

Energy Technology Data Exchange (ETDEWEB)

Xie, Xu [Saitama Univ., Saitama (Japan). Graduate School; Yamaguchi, H.; Ito, M. [Saitama Univ., Urawa (Japan). Faculty of Engineering

1996-04-21

In this study, incremental equation of cable-stayed bridge is formulated by finite element method taking the geometrical nonlinear analysis into account. Then, as an example of designing a bridge with 1500m span, setting up the initial tension, analysis of in-plane behavior caused by live loads as well as analysis of the behavior against wind caused by out-of-plane wind load that are necessary for designing a bridge with 1500m span are carried out. The main results obtained through the study are as follows. As for the cable stayed bridge with 1500m center super long-span having supplementary supporting points between the side arms, the geometrical non-linearity caused by the in-plane design live loads is not remarkable. The effects of wind which acts on girders on analysis of the behaviors against wind are different depending on the aerodynamic performance of the girder and in the case of high wind speed, strong effects on the behavior against wind of the in-plane and screws generate. As the changing of tension of the cable makes influences on the force of in-plane cross section and on displacement of the girder, if the wind speed is very high, the analysis results of the behaviors against wind of in-plane and screws of the cable-stayed bridge may be different depending on in what manner the wind load on the cable to be treated. 16 refs., 16 figs., 1 tab.

Structure-borne noise of railway composite bridge: Numerical simulation and experimental validation

Science.gov (United States)

Li, Xiaozhen; Liu, Quanmin; Pei, Shiling; Song, Lizhong; Zhang, Xun

2015-09-01

In order to investigate the characteristics of the noise from steel-concrete composite bridges under high-speed train loading, a model used to predict the bridge-borne noise is established and validated through a field experiment. The numerical model for noise prediction is developed based on the combination of spatial train-track-bridge coupled vibration theory and Statistical Energy Analysis (SEA). Firstly, train-track-bridge coupled vibration is adopted to obtain the velocity time history of the bridge deck vibration. Then, the velocity time history is transferred into frequency domain through FFT to serve as the vibratory energy of SEA deck subsystems. Finally, the transmission of the vibratory energy is obtained by solving the energy balance equations of SEA, and the sound radiation is computed using the vibro-acoustic theory. The numerically computed noise level is verified by a field measurement. It is determined that the dominant frequency of steel-concrete composite bridge-borne noise is 20-1000 Hz. The noise from the bottom flange of steel longitudinal girder is less than other components in the whole frequency bands, while the noise from web of steel longitudinal girder is dominant in high frequency range above 315 Hz. The noise from concrete deck dominates in low-frequency domain ranges from 80 Hz to 160 Hz.

Author Details

African Journals Online (AJOL)

Experimental Study on Flexural Response of FRP Strengthened Masonry Beams Abstract PDF · Vol 34, No 4 (2015) - Building, Civil & Geotechical Engineering Numerical and Experimental Modeling of the Static Response of Simply Supported Thin-Walled Box Girder Bridges Abstract PDF. ISSN: 2467-8821. AJOL African ...

Nigerian Journal of Technology - Vol 33, No 4 (2014)

African Journals Online (AJOL)

Evaluation of the Suitability of Low-Density Polyethylene (LDPE) Waste as Fine Aggregate in Concrete · EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT DOWNLOAD FULL ... Stress Distribution in Continuous Thin-Walled Multi-Cell Box Girder Bridges · EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT DOWNLOAD ...

Impact Coefficient Analysis of Long-Span Railway Cable-Stayed Bridge Based on Coupled Vehicle-Bridge Vibration

Directory of Open Access Journals (Sweden)

Yongle Li

2015-01-01

Full Text Available Compared with medium and small span bridges, very limited attention has been paid on the research of the impact coefficient of long-span railway bridges. To estimate the impact effects of long-span railway bridges subjected to moving vehicles, a real long-span railway cable-stayed bridge is regarded as the research object in this study, and a coupled model of vehicle-bridge system is established. The track irregularities are taken as the system excitation and the dynamic responses of the vehicle-bridge system are calculated. The impact effects on main girder, stayed cable, bearings, and bridge tower are discussed at various vehicle speeds. The results show that different components of the long-span railway cable-stayed bridge have different impact coefficients. Even for each part, the impact coefficient is also different at different local positions. It reveals that the impact coefficients in the actual situation may have significant differences with the related code clauses in the present design codes.

Evaluating the time-dependent and bond characteristics of lightweight concrete mixes for Kansas prestressed concrete bridges : technical summary.

Science.gov (United States)

2011-07-01

The majority of the bridges in Kansas are in rural areas. Many of these are : becoming structurally deficient, and are in need of replacement. Due to the location of : these bridges, cost of transporting prestressed girders to these areas often makes...

Estimation of Curvature Changes for Steel-Concrete Composite Bridge Using Fiber Bragg Grating Sensors

OpenAIRE

Kang, Donghoon; Chung, Wonseok

2013-01-01

This study is focused on the verification of the key idea of a newly developed steel-concrete composite bridge. The key idea of the proposed bridge is to reduce the design moment by applying vertical prestressing force to steel girders, so that a moment distribution of a continuous span bridge is formed in a simple span bridge. For the verification of the key technology, curvature changes of the bridge should be monitored sequentially at every construction stage. A pair of multiplexed FBG sen...

Discrete vortex method simulations of aerodynamic admittance in bridge aerodynamics

DEFF Research Database (Denmark)

Rasmussen, Johannes Tophøj; Hejlesen, Mads Mølholm; Larsen, Allan

, and to determine aerodynamic forces and the corresponding flutter limit. A simulation of the three-dimensional bridge responseto turbulent wind is carried out by quasi steady theory by modelling the bridge girder as a line like structure [2], applying the aerodynamic load coefficients found from the current version......The meshless and remeshed Discrete Vortex Method (DVM) has been widely used in academia and by the industry to model two-dimensional flow around bluff bodies. The implementation “DVMFLOW” [1] is used by the bridge design company COWI to determine and visualise the flow field around bridge sections...

Dynamic Analysis of Cable-Stayed Bridges Affected by Accidental Failure Mechanisms under Moving Loads

Directory of Open Access Journals (Sweden)

Fabrizio Greco

2013-01-01

Full Text Available The dynamic behavior of cable-stayed bridges subjected to moving loads and affected by an accidental failure in the cable suspension system is investigated. The main aim of the paper is to quantify, numerically, the dynamic amplification factors of typical kinematic and stress design variables, by means of a parametric study developed in terms of the structural characteristics of the bridge components. The bridge formulation is developed by using a geometric nonlinear formulation, in which the effects of local vibrations of the stays and of large displacements in the girder and the pylons are taken into account. Explicit time dependent damage laws, reproducing the failure mechanism in the cable system, are considered to investigate the influence of the failure mode characteristics on the dynamic bridge behavior. The analysis focuses attention on the influence of the inertial characteristics of the moving loads, by accounting coupling effects arising from the interaction between girder and moving system. Sensitivity analyses of typical design bridge variables are proposed. In particular, the effects produced by the moving system characteristics, the tower typologies, and the failure mode characteristics involved in the cable system are investigated by means of comparisons between damaged and undamaged bridge configurations.

STRESS-DEFORMED STATE OF A STRUT-FRAMED CRANE GIRDER

Directory of Open Access Journals (Sweden)

Kh. M. Muselemov

2017-01-01

Full Text Available Objectives. The aim of the present work is to study the influence of design parameters on the stress-deformed state of a sprengel crane girder; to compile the tables and corresponding graphs illustrating changes in internal force factors in the characteristic cross-sections of the system elements under consideration. The article describes the study of the stress-deformed state (SDS of a metal strut-framed crane girder.Methods. Numerical methods of analysis based on the use of the Green's function are used during solving this problem. A dimensionless parameter is introduced, depending on which the tables and graphs are constructed. According to the known algorithm, the calculations of internal force factors in the sections of the considered construction are performed.Results. Depending on the dimensionless parameter characterising the geometry and physical features of the system, tables of bending moments and transverse forces are compiled. According to these tables, the appropriate graphs are plotted in order to choose easily the optimal design parameters.Conclusion. The dependence of the moments and transverse forces on the dimensionless parameter k was found, the corresponding graphs were plotted and the metal costs for the girders were calculated. The minimum values of the moments and transverse forces are established to take place when the dimensionless parameter k values are close to zero. The most economical was a strut-framed crane girder having k = 0.0001. The most uneconomical had k = 0.05 and k =∞. Eventually, the sprengel girders were found to be more profitable as compared to conventional crane girders. In the examples considered in the article, the metal savings amounted up to 14%. The presented methodology allows the calculation and designing of strut-framed crane girders with two racks to be carried out. 

Impact of measurement uncertainty from experimental load distribution factors on bridge load rating

Science.gov (United States)

Gangone, Michael V.; Whelan, Matthew J.

2018-03-01

Load rating and testing of highway bridges is important in determining the capacity of the structure. Experimental load rating utilizes strain transducers placed at critical locations of the superstructure to measure normal strains. These strains are then used in computing diagnostic performance measures (neutral axis of bending, load distribution factor) and ultimately a load rating. However, it has been shown that experimentally obtained strain measurements contain uncertainties associated with the accuracy and precision of the sensor and sensing system. These uncertainties propagate through to the diagnostic indicators that in turn transmit into the load rating calculation. This paper will analyze the effect that measurement uncertainties have on the experimental load rating results of a 3 span multi-girder/stringer steel and concrete bridge. The focus of this paper will be limited to the uncertainty associated with the experimental distribution factor estimate. For the testing discussed, strain readings were gathered at the midspan of each span of both exterior girders and the center girder. Test vehicles of known weight were positioned at specified locations on each span to generate maximum strain response for each of the five girders. The strain uncertainties were used in conjunction with a propagation formula developed by the authors to determine the standard uncertainty in the distribution factor estimates. This distribution factor uncertainty is then introduced into the load rating computation to determine the possible range of the load rating. The results show the importance of understanding measurement uncertainty in experimental load testing.

Seismic vulnerability assessment of a continuous steel box girder ...

Indian Academy of Sciences (India)

Tae-Hyung Lee

2018-02-07

Feb 7, 2018 ... nonlinear time history analysis is the most widely used and the most reliable method ... the damage probability for the non-isolated bridge is larger than those of the isolated .... [17] and are adjusted for a simulated facilitation purpose. ..... function is assumed as a log-normal cumulative distribution function ...

Increased of the capacity integral bridge with reinforced concrete beams for single span

Science.gov (United States)

Setiati, N. Retno

2017-11-01

Sinapeul Bridge that was built in 2012 in Sumedang is a bridge type using a full integral system. The prototype of integral bridge with reinforced concrete girder and single span 20 meters until this year had decreased capacity. The bridge was conducted monitoring of strain that occurs in the abutment in 2014. Monitoring results show that based on the data recorded, the maximum strain occurs at the abutment on the location of the integration of the girder of 10.59 x 10-6 tensile stress of 0.25 MPa (smaller than 150 x 10-6) with 3 MPa tensile stress as limit the occurrence of cracks in concrete. Sinapeul bridge abutment with integral system is still in the intact condition. Deflection of the bridge at the time of load test is 1.31 mm. But this time the bridge has decreased exceeded permission deflection (deflection occurred by 40 mm). Besides that, the slab also suffered destruction. One cause of the destruction of the bridge slab is the load factor. It is necessary for required effort to increase the capacity of the integral bridge with retrofitting. Retrofitting method also aims to restore the capacity of the bridge structure due to deterioration. Retrofitting can be done by shortening of the span or using Fibre Reinforced Polymer (FRC). Based on the results obtained by analysis of that method of retrofitting with Fibre Reinforced Polymer (FRC) is more simple and effective. Retrofitting with FRP can increase the capacity of the shear and bending moment becomes 41% of the existing bridge. Retrofitting with FRP method does not change the integral system on the bridge Sinapeul become conventional bridges.

A Damage Prognosis Method of Girder Structures Based on Wavelet Neural Networks

Directory of Open Access Journals (Sweden)

Rumian Zhong

2014-01-01

Full Text Available Based on the basic theory of wavelet neural networks and finite element model updating method, a basic framework of damage prognosis method is proposed in this paper. Firstly, a damaged I-steel beam model testing is used to verify the feasibility and effectiveness of the proposed damage prognosis method. The results show that the predicted results of the damage prognosis method and the measured results are very well consistent, and the maximum error is less than 5%. Furthermore, Xinyihe Bridge in the Beijing-Shanghai Highway is selected as the engineering background, and the damage prognosis is conducted based on the data from the structural health monitoring system. The results show that the traffic volume will increase and seasonal differences will decrease in the next year and a half. The displacement has a slight increase and seasonal characters in the critical section of mid span, but the strain will increase distinctly. The analysis results indicate that the proposed method can be applied to the damage prognosis of girder bridge structures and has the potential for the bridge health monitoring and safety prognosis.

Wave induced extreme hull girder loads on containerships

DEFF Research Database (Denmark)

Jensen, Jørgen Juncher; Pedersen, Preben Terndrup; Shi, Bill

2009-01-01

This paper provides simple but rational procedures for prediction of extreme wave – induced sectional hull girder forces with reasonable engineering accuracy. The procedures take into account main ship hull characteristics such as: length, breadth, draught, block coefficient, bow flare coefficient......, forward speed and hull flexibility. The vertical hull girder loads are evaluated for specific operational profiles. Firstly a quadratic strip theory is presented which can give separate predictions for the hogging and sagging bending moments and shear forces and for hull girder loads. Then this procedure...... is based on rational methods it can be applied for novel single hull ship types not presently covered by the rules of the classification societies or to account for specific operational profiles....

Monitoring Bridge Dynamic Responses Using Fiber Bragg Grating Tiltmeters.

Science.gov (United States)

Xiao, Feng; Chen, Gang S; Hulsey, J Leroy

2017-10-20

In bridge health monitoring, tiltmeters have been used for measuring rotation and curvature; however, their application in dynamic parameter identification has been lacking. This study installed fiber Bragg grating (FBG) tiltmeters on the bearings of a bridge and monitored the dynamic rotational angle. The dynamic features, including natural frequencies and mode shapes, have been identified successfully. The innovation presented in this paper is the first-time use of FBG tiltmeter readings to identify the natural frequencies of a long-span steel girder bridge. The identified results have been verified using a bridge finite element model. This paper introduces a new method for the dynamic monitoring of a bridge using FBG tiltmeters. Limitations and future research directions are also discussed in the conclusion.

Monitoring Bridge Dynamic Responses Using Fiber Bragg Grating Tiltmeters

Directory of Open Access Journals (Sweden)

Feng Xiao

2017-10-01

Full Text Available In bridge health monitoring, tiltmeters have been used for measuring rotation and curvature; however, their application in dynamic parameter identification has been lacking. This study installed fiber Bragg grating (FBG tiltmeters on the bearings of a bridge and monitored the dynamic rotational angle. The dynamic features, including natural frequencies and mode shapes, have been identified successfully. The innovation presented in this paper is the first-time use of FBG tiltmeter readings to identify the natural frequencies of a long-span steel girder bridge. The identified results have been verified using a bridge finite element model. This paper introduces a new method for the dynamic monitoring of a bridge using FBG tiltmeters. Limitations and future research directions are also discussed in the conclusion.

An Optimization Algorithm for the Design of an Irregularly-Shaped Bridge Based on the Orthogonal Test and Analytic Hierarchy Process

Directory of Open Access Journals (Sweden)

Hanbing Liu

2016-11-01

Full Text Available Irregularly-shaped bridges are usually adopted to connect the main bridge and ramps in urban overpasses, which are under significant flexion-torsion coupling effects and in complicated stress states. In irregular-shaped bridge design, the parameters such as ramp radius, bifurcation diaphragm stiffness, box girder height, and supporting condition could affect structural performance in different manners. In this paper, the influence of various parameters on three indices, including maximum stress, the stress variation coefficient, and the fundamental frequency of torsional vibration, is investigated and analyzed based on orthogonal test method. Through orthogonal analysis, the major influence parameters and corresponding optimal values for these indices are achieved. Combining with the analytic hierarchy process (AHP, the hierarchical structure model of the multi-indices orthogonal test is established and a comprehensive weight analysis method is proposed to reflect the parameter influence on overall mechanical properties of an irregularly-shaped bridge. Influence order and optimal values of parameters for overall mechanical properties are determined based on the weight of factors and levels calculated by the comprehensive weight analysis method. The results indicate that the comprehensive weight analysis method is superior to the overall balance method, which verifies the effectiveness and accuracy of the comprehensive weight analysis in the parameter optimization of the multi-indices orthogonal test for an irregularly-shaped bridge. Optimal parameters obtained in this paper can provide reference and guidance for parameter control in irregularly-shaped bridge design.

Experimental study on AR fiberglass connectors for bridges made of composite materials

Directory of Open Access Journals (Sweden)

Tolosana, N.

2006-06-01

Full Text Available One highly relevant aspect in composite material bridgedesing is the study of the shear connectors to be used.Composite material bridges most commonly comprise acomposite deck resting on steel or reinforced concrete girders.This article analyzes the connectors most frequentlyused in such bridges.It also reviews the connectors used in the King StormwaterChannel Bridge, whose fibreglass deck is supported bygirders made of concrete-filled carbon fibre girders.The paper advances proposals for several types of connectorsand discusses the results of push-out test run ona number of prototypes with different geometries.The results are analyzed to identify the optimum model forthe “Autovia del Cantabrico” Overpass, with its 46-m span,carbon fibre girders and AR glass shear connectors.Un aspecto relevante dentro del proyecto de un puenterealizado en materiales compuestos es el estudio de losconectores. El caso mas frecuente de puente en materialescompuestos es aquel que presenta un tablero de materialescompuestos soportado por vigas metalicas o de hormigonarmado. En este trabajo se analizaran los tipos deconectores mas utilizados en este tipo de puentesSe analizaran tambien los conectores utilizados en elKing Stormwater Channel Bridge, donde ademas deltablero en fibra de vidrio, se fabricaron las vigas en fibrasde carbono rellenas de hormigon.En este articulo se propondran varios tipos de conectoresy se presentaran los resultados experimentales correspondientesal ensayo de “push-out” de varios prototipos condiferentes geometrias.Tras evaluar los resultados, se determinara el mas idoneopara su implantacion en el Paso Superior de la Autovia delCantabrico, de 46 metros de luz y que presenta las vigasen fibra de carbono y los conectores de vidrio AR.

Steel framing strategies for highly skewed bridges to reduce/eliminate distortion near skewed supports.

Science.gov (United States)

2014-05-01

Different problems in straight skewed steel I-girder bridges are often associated with the methods used for detailing the cross-frames. Use of theoretical terms to describe these detailing methods and absence of complete and simplified design approac...

Experimental Investigation for Behavior of Spliced Continuous RC Girders Strengthened with CFRP Laminates

Directory of Open Access Journals (Sweden)

Ammar Yasir Ali

2016-03-01

Full Text Available In this paper, the behavior of spliced continuous reinforced concrete girders was experimentally investigated. The main objective was to examine the contribution of the carbon fiber reinforced polymer (CFRP laminates in strengthening the spliced continuous reinforced concrete girders. Eight models of continuous reinforced concrete girder were constructed and tested. The test variables were strengthening the splice joints by different schemes of CFRP laminates, presence of horizontal stirrups through the interfaces of the joints and using binder material at the interfaces of the joints. The results showed that strengthening the continuous spliced girders with 45° inclined CFRP laminates led to an increase in the ultimate load in a range of (47 to 74%. Besides, strengthening the continuous spliced girder with horizontal CFRP laminates bonded at its lateral faces could increase the ultimate load by 70%. Additionally, the ultimate load of the continuous spliced girder was increased by (30% due to presence of the horizontal steel stirrups through the interfaces of the joints

Microstructural characterisation and corrosion performance of old railway girder bridge steel and modern weathering structural steel

International Nuclear Information System (INIS)

Tewary, N.K.; Kundu, A.; Nandi, R.; Saha, J.K.; Ghosh, S.K.

2016-01-01

Highlights: • Microstructure and corrosion performance are compared for two structural steels. • Microstructure evolution shows primarily ferrite-pearlite in both the steels. • Steels show higher corrosion rate in 1% HCl solution than in 3.5% NaCl solution. • The corrosion products show the presence of oxide, hydroxide and oxy-hydroxides. • The corroded surface reveals morphologies like flowery, cotton balls and rosette. - Abstract: A comparison on microstructure and corrosion performance has been made between the two structural steels used in old railway girder bridge (Sample A) and modern grades of weathering structural steel (Sample B). The microstructures, viewed under optical microscope and scanning electron microscope (SEM), show mainly ferrite-pearlite phase constituents in both the steels, A and B. The phase fraction analysis shows higher amount of pearlite in steel A compared to that of steel B. The grain size of steel A is larger than that of steel B under identical processing condition. The immersion corrosion test in 3.5% NaCl shows that the corrosion rate of steel A increases with time, while the same for steel B decreases with time. On the other hand, corrosion test in 1% HCl shows that the corrosion rate of both steel A and B is higher as compared to that of NaCl which always decreases with time. The XRD analysis of corrosion products show the presence of many oxides, hydroxide and oxy-hydroxide like Lepidocrocite (γ-FeOOH), Goethite (α-FeOOH), Akaganeite (β-FeOOH), Magnetite (Fe_3O_4) and Maghemite (γ-Fe_2O_3) in both the steels. The SEM images of corroded surfaces reveal different morphologies like flowery, cotton balls and rosette etc. which indicate that the corrosion products primarily contain Lepidocrocite (γ-FeOOH), Goethite (α-FeOOH) and Akaganeite (β-FeOOH).

Numerical/experimental research on welded joints in aluminium truss girders

NARCIS (Netherlands)

van Hove, B.W.E.M.; Soetens, F.; Mazzolani, F.M.; Bellucci, F.; Faggiano, B.; Squillace, A.

2016-01-01

Welded joints in a 30 meter span aluminium truss girder were investigated numerically and experimentally. Since aluminium design rules for welded K-and N-joints in CHS truss girders were lacking the joints were checked using steel design rules. Calculations showed that the N-joints were governing

Computer modeling of road bridge for simulation moving load

Directory of Open Access Journals (Sweden)

Miličić Ilija M.

2016-01-01

Full Text Available In this paper is shown computational modelling one span road structures truss bridge with the roadway on the upper belt of. Calculation models were treated as planar and spatial girders made up of 1D finite elements with applications for CAA: Tower and Bridge Designer 2016 (2nd Edition. The conducted computer simulations results are obtained for each comparison of the impact of moving load according to the recommendations of the two standards SRPS and AASHATO. Therefore, it is a variant of the bridge structure modeling application that provides Bridge Designer 2016 (2nd Edition identical modeled in an environment of Tower. As important information for the selection of a computer applications point out that the application Bridge Designer 2016 (2nd Edition we arent unable to treat the impacts moving load model under national standard - V600. .

Probability Based Evaluation of Vehicular Bridge Load using Weigh-in-Motion Data

Directory of Open Access Journals (Sweden)

Widi Nugraha

2016-02-01

Full Text Available Load and Resistance Factored Design (LRFD method for designing bridge in Indonesia have been implemented for more than 25 years. LRFD method treating loads and strengths variables as random variables with specific safety factors for different loads and strengths variables type. The nominal loads, load factors, reduction factors, and other criteria for bridge design code can be determined to meet the reliability criteria. Statistical data of weigh-in-motion (WIM vehicular loads measurement in Northern Java highway, Cikampek - Pamanukan, West Java (2011, used in as statistical loads variable. A 25 m simple span bridge with reinforced concrete T-girder is used as a model for structural analysis due to WIM measured and nominal vehicular load based on RSNI T-02-2005, with applied bending moment of girder as the output. The distribution fitting result of applied bending moment due to WIM measured vehicular loads is lognormal. The maximum bending moment due to RSNI T-02-2005 nominal vehicular load is 842.45 kN-m and has probability of exceedance of 5x10-5. It can be concluded, for this study, that the bridge designed using RSNI T-02-2005 is safely designed, since it has reliability index, β of 5.02, higher than target reliability, β ranging from 3.50 or 3.72.

Wind tunnel experiments on unstable self-excited vibration of sectional girders

Science.gov (United States)

Král, Radomil; Pospíšil, Stanislav; Náprstek, Jiří

2014-01-01

In this paper, a wind tunnel analysis of two degrees-of-freedom system represented by sectional girders is carried out. Besides an evaluation of the aeroelastic coefficients, the analysis is focused on the influence of the natural frequency ratio on the initiation of unstable vibration, which can be of practical interest. On the phenomenological level, the paper also discusses experimentally ascertained response regimes, with an emphasis on their stability character. The attention is paid to the memory effect in the response described by the hysteresis loop together with the separation curves determining the stability boundaries. The influence of initial disturbance on the stability is examined. Two types of cross-sections were investigated: (i) rectangular one with the aspect ratio 1:5, and (ii) bridge-like cross-section with comparable principal dimensions. For both types of cross-sections, the limits of the stability are significantly affected by an intentionally introduced initial disturbance. This holds especially with regard to the rectangular profile where the separation curves create very narrow sub-domains between a stable and an unstable response, while the bridge-like cross-section demonstrates much stable behaviour.

Experimental Analysis of Stiffness of the Riveted Steel Railway Bridge Deck Members’ Joints

Directory of Open Access Journals (Sweden)

Gocál Jozef

2014-12-01

Full Text Available The paper deals with the real behaviour of the riveted steel railway bridge deck members’ connections with respect to their bending stiffness. Attention is paid to the stringer-to-cross beam connection as well as the cross beam-to-main girder connection. The stiffness of the two connections is investigated on the basis of evaluation of the experimentally determined stress response of the observed structural members to the actual traffic load on an existing railway bridge.

Investigation of Ultimate Strength of Composite Open-Web Joist-Girders

OpenAIRE

Showalter, Sheldon Lee

1999-01-01

The goal of this research was to study several methods of generating composite action using open-web joist-girders, designed and manufactured by Nucor Corporation. In addition to comparing the relative performance of these systems, it was intended to determine whether the current accepted design procedure for composite joists could be extended to joist-girders.

Wireless Smart Sensor Network System Using SmartBridge Sensor Nodes for Structural Health Monitoring of Existing Concrete Bridges

Science.gov (United States)

Gaviña, J. R.; Uy, F. A.; Carreon, J. D.

2017-06-01

There are over 8000 bridges in the Philippines today according to the Department of Public Works and Highways (DPWH). Currently, visual inspection is the most common practice in monitoring the structural integrity of bridges. However, visual inspections have proven to be insufficient in determining the actual health or condition of a bridge. Structural Health Monitoring (SHM) aims to give, in real-time, a diagnosis of the actual condition of the bridge. In this study, SmartBridge Sensor Nodes were installed on an existing concrete bridge with American Association of State Highway and Transportation Officials (AASHTO) Type IV Girders to gather vibration of the elements of the bridge. Also, standards on the effective installation of SmartBridge Sensor Nodes, such as location and orientation was determined. Acceleration readings from the sensor were then uploaded to a server, wherein they are monitored against certain thresholds, from which, the health of the bridge will be derived. Final output will be a portal or webpage wherein the information, health, and acceleration readings of the bridge will be available for viewing. With levels of access set for different types of users, the main users will have access to download data and reports. Data transmission and webpage access are available online, making the SHM system wireless.

Influence of Pavement on Fatigue Performance of Urban Steel Box Girder Deck

Directory of Open Access Journals (Sweden)

Zheng Zhongyue

2016-01-01

Full Text Available Based on spatial finite element analysis method, the Influence of pavement on fatigue performance of orthotropic steel deck was analyzed in terms of pavement system, asphalt pavement stiffness. The result shows that compared with asphalt pavement system, RPC pavement system can not only obviously improve the stress condition of steel bridge deck, but also significantly extend the fatigue life of steel bridge panel; Increasing the stiffness of pavement layer can obviously reduce the stress amplitude of fatigue details, especially for direct contact with the pavement.

Random Young diagrams in a Rectangular Box

DEFF Research Database (Denmark)

Beltoft, Dan; Boutillier, Cédric; Enriquez, Nathanaël

We exhibit the limit shape of random Young diagrams having a distribution proportional to the exponential of their area, and confined in a rectangular box. The Ornstein-Uhlenbeck bridge arises from the fluctuations around the limit shape.......We exhibit the limit shape of random Young diagrams having a distribution proportional to the exponential of their area, and confined in a rectangular box. The Ornstein-Uhlenbeck bridge arises from the fluctuations around the limit shape....

Skewed steel bridges, part ii : cross-frame and connection design to ensure brace effectiveness : technical summary.

Science.gov (United States)

2017-08-01

Skewed bridges in Kansas are often designed such that the cross-frames are carried parallel to the skew angle up to 40, while many other states place cross-frames perpendicular to the girder for skew angles greater than 20. Skewed-parallel cross-...

Skewed steel bridges, part ii : cross-frame and connection design to ensure brace effectiveness : final report.

Science.gov (United States)

2017-08-01

Skewed bridges in Kansas are often designed such that the cross-frames are carried parallel to the skew angle up to 40, while many other states place cross-frames perpendicular to the girder for skew angles greater than 20. Skewed-parallel cross-...

Flexible concrete link slabs used as expansion joints in bridge decks

DEFF Research Database (Denmark)

Lárusson, Lárus Helgi; Fischer, Gregor

2011-01-01

of water through the expansion joint and subsequent corrosion of girders and girder bearings. Investigations on joint-less superstructures using conventional steel reinforcement in so-called concrete link slabs indicate improved performance and economic feasibility. However, this concept requires...... relatively large amounts of steel reinforcement for crack control purposes and consequently provides a relatively large flexural stiffness and negative moment capacity at the joint between the spans. These contradicting requirements and effects in existing replacement concepts for damaged mechanical bridge...... joints are currently unresolved. In the proposed system described in this paper, a ductile cement-based composite section reinforced with Glass Fiber Reinforced Polymers (GFRP) replaces the damaged expansion joint. The combination of this ductile concrete together with corrosion resistant GFRP...

Structural Behavior of a Long-Span Partially Earth-Anchored Cable-Stayed Bridge during Installation of a Key Segment by Thermal Prestressing

Directory of Open Access Journals (Sweden)

Sang-Hyo Kim

2016-08-01

Full Text Available This study investigated structural behavior of long-span partially earth-anchored cable-stayed bridges with a main span length of 810 m that use a new key segment closing method based on a thermal prestressing technique. A detailed construction sequence analysis matched with the free cantilever method (FCM was performed using a three-dimensional finite element (FE model of a partially earth-anchored cable-stayed bridge. The new method offers an effective way of connecting key segments by avoiding large movements resulting from the removal of the longitudinal restraint owing to the asymmetry of axial forces in the girders near the pylons. The new method develops new member forces through the process of heating the cantilever system before installing the key segment and cooling the system continuously after installing key segments. The resulting forces developed by the thermal process enhance the structural behavior of partially earth-anchored cable-stayed bridges owing to decreased axial forces in the girders.

Practical cable tension adjustment based upon the satisfaction concept of bridge designers; Sekkeisha no manzokudo wo koryo shita fuzzy cable choryoku choseiho

Energy Technology Data Exchange (ETDEWEB)

Kaneyoshi, M.; Tanaka, H. [Hitachi Zosen, Tokyo (Japan)] Furuta, H. [Kansai Univ., Osaka (Japan)

1998-07-21

Cable tension adjustment of bridge beam of cable stayed bridge and so forth that uses cable as a structural element is classified into (1) pre-stress adjustment of cable at design level, (2) slim adjustment required at erection level. The former deals with the structurally high dimensional statically indeterminate structures like cable-stayed bridges and is a process for carrying out economical design by making the stress resultant of main girder small due to the introduction of appropriate pre-stress stress on this cable. The later is the process of getting rid off the errors caused in cable tension and camber of girder and tower regarding various errors such as design, fabrication and erection errors. The authors developed analysis method using fuzzy regression analysis and this has been applied in number of practical bridges. In this research, much more practical method is developed where the aspire of designer can be introduced easily by applying the satisfaction concept. By using this, pre-stress adjustment and shim adjustment of cable can be possible in a practical way. 9 refs., 7 figs., 8 tabs.

Steel bridges structural health monitoring based on operational modal analysis accommodating evaluation of uncertainty

Directory of Open Access Journals (Sweden)

Saeid Jahan

2017-11-01

Full Text Available Structural damage detection is based on that the dynamic response of structure will change because of damage. Hence, it is possible to estimate the location and severity of damage leads to changes in the dynamic response before and after the damage. In this study, the genetic fuzzy system has been used for bridge structural health monitoring. A key objective of using genetic algorithms is to automate the design of fuzzy systems. This method is used for damage detection of a single span railway bridge with steel girders and a concrete bridge. For studying damage detection, the numerical models of these two bridges are built with the measured dynamic characteristics. A three-dimensional finite element model and a single two-dimensional girders model of the bridge have been constructed to study usefulness of the genetic fuzzy system for damage detection and the effectiveness of modeling. After analysis to control the uncertainties, the measured frequencies are contaminated with some noise and the effect of that on the achievement of damage detection method is evaluated. The present study has shown that the natural frequency has appropriate sensitivity to different damage scenarios in the structure. In addition, the natural frequency in comparison with other modal parameters, is less affected by random noise. Increasing the number of measurement modes and using torsional modes, will lead to an accurate damage diagnosis even in symmetrical structures.

Exciting test of a floating type cable stayed bridge and its response observation under the typhoon; Furotiingu keishiki shachokyo (Utagenkabashi) no kishinki shiken to taifuji oto kansoku

Energy Technology Data Exchange (ETDEWEB)

Uno, K. [Kyushu Kyoritsu Univ., Kitakyushu (Japan). Faculty of Engineering; Aso, T. [Yamaguchi Univ., Ube (Japan). Faculty of Engineering; Kitagawa, S. [Kyushu International Univ., Kitakyushu (Japan). Faculty of Economy; Kabashima, S.

1995-09-20

Recently, in case of the planning and designing of bridges, of course its practicality and execution stability are considered, but consideration for landscape also is a large problem. In particular, the selection of the bridge type is very important in order to protect the beautiful natural landscape. The cable stayed bridge has become to be executed often, owing to its elegant style, however, it becomes important theme clarify the antiseismic and wind stability because of its complicated structure system and very slender girder. In this paper, the results of the dynamic characteristics of a floating type cable stayed bridge (length 292.1 m and width 14.9 m) and the observation of its dynamic behavior under the typhoon are reported. Microtremor measurement was performed to determine the dynamic characteristics of the bridge under construction. After the construction of the bridge, the excitation test was carried out in order to confirm its natural frequencies, vibration modes and damping constants. From the results of the observation of the dynamic behavior of the girder and cables under the typhoon, the wind stability of this bridge was confirmed. 10 refs., 13 figs., 9 tabs.

A software prototype for assessing the reliability of a concrete bridge superstructure subjected to chloride-induced reinforcement corrosion

DEFF Research Database (Denmark)

Schneider, Ronald; Thöns, Sebastian; Fischer, Johannes

2014-01-01

state of the box girder and a structural model for evaluating the overall system reliability. The condition model is based on a dynamic Bayesian network (DBN) model which considers the spatial variation of the corrosion process. Inspection data are included in the calculation of the system reliability...

Nondestructive Evaluation of Railway Bridge by System Identification Using Field Vibration Measurement

International Nuclear Information System (INIS)

Ho, Duc Duy; Hong, Dong Soo; Kim, Jeong Tae

2010-01-01

This paper presents a nondestructive evaluation approach for system identification (SID) of real railway bridges using field vibration test results. First, a multi-phase SID scheme designed on the basis of eigenvalue sensitivity concept is presented. Next, the proposed multi-phase approach is evaluated from field vibration tests on a real railway bridge (Wondongcheon bridge) located in Yangsan, Korea. On the steel girder bridge, a few natural frequencies and mode shapes are experimentally measured under the ambient vibration condition. The corresponding modal parameters are numerically calculated from a three-dimensional finite element (FE) model established for the target bridge. Eigenvalue sensitivities are analyzed for potential model-updating parameters of the FE model. Then, structural subsystems are identified phase-by-phase using the proposed model-updating procedure. Based on model-updating results, a baseline model and a nondestructive evaluation of test bridge are identified

Strength Enhancement of Prestressed Concrete Dapped-End Girders

Directory of Open Access Journals (Sweden)

Shatha Dhia Mohammed

2015-10-01

Full Text Available This paper presents the application of nonlinear finite element models in the analysis of dapped-ends pre-stressed reinforced concrete girders under static loading by using ANSYS software. The girder dimensions are (4.90 m span, 0.40 m depth, 0.20 m width, 0.20 m nib depth, and 0.10 m nib length and the parameters considered in this research are the pre-stress effect, and strand profile (straight and draped. The numerical results are compared with the experimental results of the same girders. The comparisons are carried out in terms of initial prestress effect, load- deflection curve, and failure load. Good agreement was obtained between the analytical and experimental results. Even that, the numerical model was stiffer than the experimental, but; there were a good agreements in both trends and values. The difference varies in the range (5-12% for the deflection. Results have shown that the pre-stress force has increased the static ultimate load capacity by (35% in case of straight strand and by (97% in case of draped strand

Evaluation of post-tensioning of a curved continuous girder using long-gauge fiber optic sensors

Science.gov (United States)

Abdel-Jaber, Hiba; Glisic, Branko

2014-03-01

Streicker Bridge is a pedestrian bridge on the Princeton University campus. It consists of a main span and four curved continuous girders (legs). The main span and the southeast leg of the bridge are equipped with fiber optic strain and temperature sensors, allowing the bridge to also function as an on-campus laboratory for the Structural Health Monitoring research group. Parallel sensors were embedded at critical cross-sections in the deck prior to the pouring of concrete. The deck of the southeast leg experienced early age cracking within a few days of concrete pouring, which was detected by the strain sensors. Post-tensioning was then performed and it is assumed that it closed off the cracks. Evaluation of post-tensioning forces is complex due to the existence of the cracks, and this paper researches a procedure to estimate the post-tensioning forces at cracked and uncracked locations. The obtained post-tensioning forces were compared to design forces and conclusions regarding the status of post-tensioning were made. This is important as it gives information on the actual health condition and performance of the structure. It also provides information on the safety of the structure. The objective of this paper is to present a methodology for the evaluation of the post-tensioning force along the deck based on strain measurements. The monitoring system, results, data analysis method, and conclusions regarding the bridge health condition and performance are presented in this paper.

Evaluation of High-Speed Railway Bridges Based on a Nondestructive Monitoring System

Directory of Open Access Journals (Sweden)

Mosbeh R. Kaloop

2016-01-01

Full Text Available Recently, trains’ velocities in Korea increased more than the speed used in the design of some bridges. Accordingly, this paper demonstrates the evaluation of a railway bridge due to high-speed trains’ movement. A nondestructive monitoring system is used to assess the bridge performance under train speeds of 290, 360, 400 and 406 km/h. This system is comprised of a wireless short-term acceleration system and strain monitoring sensors attached to the bridge girder. The results of the analytical methods in time and frequency domains are presented. The following conclusions are obtained: the cross-correlation models for accelerations and strain measurements are effective to predict the performance of the bridge; the static behavior is increased with train speed developments; and the vibration, torsion, fatigue and frequency contents analyses of the bridge show that the bridge is safe under applied trains’ speeds.

Numerical analysis of dynamic response of vehicle–bridge coupled system on long-span continuous girder bridge

OpenAIRE

An, Lipeng; Li, Dejian; Yu, Peng; Yuan, Peng

2016-01-01

To systematically study the vehicle–bridge coupled dynamic response and its change rule with different parameters, a vehicle model with seven degrees of freedom was built and the total potential energy of vehicle space vibration system was deduced. Considering the stimulation of road roughness, the dynamic response equation of vehicle–bridge coupled system was established in accordance with the elastic system principle of total potential energy with stationary value and the “set-in-right-posi...

Hybrid Bridge Structures Made of Frp Composite and Concrete

Science.gov (United States)

Rajchel, Mateusz; Siwowski, Tomasz

2017-09-01

Despite many advantages over the conventional construction materials, the contemporary development of FRP composites in bridge engineering is limited due to high initial cost, low stiffness (in case of glass fibers) and sudden composite failure mode. In order to reduce the given limitations, mixed (hybrid) solutions connecting the FRP composites and conventional construction materials, including concrete, have been tested in many countries for 20 years. Shaping the hybrid structures based on the attributes of particular materials, aims to increase stiffness and reduce cost without losing the carrying capacity, lightness and easiness of bridges that includes such hybrid girders, and to avoid the sudden dangerous failure mode. In the following article, the authors described examples of hybrid road bridges made of FRP composite and concrete within the time of 20 years and presented the first Polish hybrid FRP-concrete road bridge. Also, the directions of further research, necessary to spread these innovative, advanced and sustainable bridge structures were indicated.

Super-long bridges with floating towers: the role of multi-box decks and Hardware-In-the-Loop technology for wind tunnel tests

Science.gov (United States)

Zasso, A.; Argentini, T.; Bayati, I.; Belloli, M.; Rocchi, D.

2017-12-01

The super long fjord crossings in E39 Norwegian project pose new challenges to long span bridge design and construction technology. Proposed solutions should consider the adoption of bridge deck with super long spans or floating solutions for at least one of the towers, due to the relevant fjord depth. At the same time, the exposed fjord environment, possibly facing the open ocean, calls for higher aerodynamic stability performances. In relation to this scenario, the present paper addresses two topics: 1) the aerodynamic advantages of multi-box deck sections in terms of aeroelastic stability, and 2) an experimental setup in a wind tunnel able to simulate the aeroelastic bridge response including the wave forcing on the floating.

APPLICATION OF ULTRA-HIGH PERFORMANCE CONCRETE TO PEDESTRIAN CABLE-STAYED BRIDGES

Directory of Open Access Journals (Sweden)

CHI-DONG LEE

2013-06-01

Full Text Available The use of ultra-high performance concrete (UHPC, which enables reducing the cross sectional dimension of the structures due to its high strength, is expected in the construction of the super-long span bridges. Unlike conventional concrete, UHPC experiences less variation of material properties such as creep and drying shrinkage and can reduce uncertainties in predicting time-dependent behavior over the long term. This study describes UHPC’s material characteristics and benefits when applied to super-long span bridges. A UHPC girder pedestrian cable-stayed bridge was designed and successfully constructed. The UHPC reduced the deflections in both the short and long term. The cost analysis demonstrates a highly competitive price for UHPC. This study indicates that UHPC has a strong potential for application in the super-long span bridges.

Field performance of timber bridges. 9, Big Erick`s stress-laminated deck bridge

Science.gov (United States)

J. A. Kainz; J. P. Wacker; M. Nelson

The Big Erickas bridge was constructed during September 1992 in Baraga County, Michigan. The bridge is 72 ft long, 16 ft wide, and consists of three simple spans: two stress-laminated deck approach spans and a stress-laminated box center span. The bridge is unique in that it is one of the first known stress-laminated timber bridge applications to use Eastern Hemlock...

Bridge Failure Due to Inadequate Design of Bed Protection

Science.gov (United States)

Gupta, Yogita; Kaur, Suneet; Dindorkar, Nitin

2017-12-01

The shallow foundation is generally provided on non-erodible strata or where scour depth is less. It is also preferable for low perennial flow or standing water condition. In the present case study shallow foundation is adopted for box type bridge. The total length of the bridge is 132.98 m, consisting of eight unit of RCC box. Each unit is composed of three cell box. The bottom slab of box unit is acted as raft foundation, founded 500 mm below ground level. River bed protection work is provided on both upstream and downstream side along the whole length of the bridge as it is founded above scour level. The bridge collapsed during the monsoon just after two years of service. The present paper explains the cause of failure. This study on failure of the bridge illustrates the importance of bridge inspection before and after monsoon period and importance of the timely maintenance. Standard specifications of Indian Road Congress for the river bed protection work are also included.

Estimation of Curvature Changes for Steel-Concrete Composite Bridge Using Fiber Bragg Grating Sensors

Directory of Open Access Journals (Sweden)

Donghoon Kang

2013-01-01

Full Text Available This study is focused on the verification of the key idea of a newly developed steel-concrete composite bridge. The key idea of the proposed bridge is to reduce the design moment by applying vertical prestressing force to steel girders, so that a moment distribution of a continuous span bridge is formed in a simple span bridge. For the verification of the key technology, curvature changes of the bridge should be monitored sequentially at every construction stage. A pair of multiplexed FBG sensor arrays is proposed in order to measure curvature changes in this study. They are embedded in a full-scale test bridge and measured local strains, which are finally converted to curvatures. From the result of curvature changes, it is successfully ensured that the key idea of the proposed bridge, expected theoretically, is viable.

Acoustic emission techniques applied to conventionally reinforced concrete bridge girders.

Science.gov (United States)

2008-09-01

Reinforced concrete (RC) bridges generally operate at service-level loads except during discrete overload events that can reduce the integrity of the structure by initiating concrete cracks, widening or extending of existing concrete cracks, as well ...

Determination of in-situ strength on selected bridge element concrete girder and slab of Nagtahan bridge using rebound hammer test

International Nuclear Information System (INIS)

Uy, Bernadette Betsy B.; Banaga, Renato T.

2013-01-01

This study examined the extent of the damage due to fire on the affected areas of the bridge structure. The need to assess the damage of the Nagtahan Bridge is very useful to provide appropriate measures in the repair or in the reinforcement of the bridge, hence will ensure its strength and integrity. The study included two (2) spans of the bridge deck/slab with specific locations of the bridge that were subjected for testing. The Rebound Hammer was used as a preliminary test in evaluating the bridge condition. Its capability is to assess the in-place uniformity of concrete, to delineate regions in a structure of poor quality or deteriorated concrete, and to estimate the in-place strength; and ultimately, for relative comparison between the different structures of the bridge. With the use of the NDT Rebound Hammer Test, the researchers were able to determine whether or not the in-situ strength of the bridge's concrete has been weakened due to fire. The DPW-Standard Specification is the government acceptable manual, containing the acceptance criteria, used as the basis for standard construction procedures in the department.(author)

Damage Detection for Continuous Bridge Based on Static-Dynamic Condensation and Extended Kalman Filtering

Directory of Open Access Journals (Sweden)

Haoxiang He

2014-01-01

Full Text Available As an effective and classical method about physical parameter identification, extended Kalman filtering (EKF algorithm is widely used in structural damage identification, but the equations and solutions for the structure with bending deformation are not established based on EKF. The degrees of freedom about rotation can be eliminated by the static condensation method, and the dynamic condensation method considering Rayleigh damping is proposed in order to establish the equivalent and simplified modal based on complex finite element model such as continuous girder bridge. According to the requirement of bridge inspection and health monitoring, the online and convenient damage detection method based on EKF is presented. The impact excitation can be generated only on one location by one hammer actuator, and the signal in free vibration is analyzed. The deficiency that the complex excitation information is needed based on the traditional method is overcome. As a numerical example, a three-span continuous girder bridge is simulated, and the corresponding stiffness, the damage location and degree, and the damping parameter are identified accurately. It is verified that the method is suitable for the dynamic signal with high noise-signal ratio; the convergence speed is fast and this method is feasible for application.

INVESTIGATION OF LAUNCHING PROCESS FOR STEEL REINFORCED CONCRETE FRAMEWORK OF LARGE BRIDGES

Directory of Open Access Journals (Sweden)

V. A. Grechukhin

2017-01-01

Full Text Available Bridges are considered as the most complicated, labour-consuming and expensive components in roadway network of the Republic of Belarus. So their construction and operation are to be carried out at high technological level. One of the modern industrial methods is a cyclic longitudinal launching of large frameworks which provide the possibility to reject usage of expensive auxiliary facilities and reduce a construction period. There are several variants of longitudinal launching according to shipping conditions and span length: without launching girder, with launching girder, with top strut-framed beam in the form of cable-stayed system, with strut-framed beam located under span. While using method for the cyclic longitudinal launching manufacturing process of span is concentrated on the shore. The main task of the investigations is to select economic, quick and technologically simple type of the cyclic longitudinal launching with minimum resource- and labour inputs. Span launching has been comparatively analyzed with temporary supports being specially constructed within the span and according to capital supports with the help of launching girder. Conclusions made on the basis of calculations for constructive elements of span according to bearing ability of element sections during launching and also during the process of reinforced concrete plate grouting and at the stage of operation have shown that span assembly with application of temporary supports does not reduce steel spread in comparison with the variant excluding them. Results of the conducted investigations have been approbated in cooperation with state enterprise “Belgiprodor” while designing a bridge across river Sozh.

Improved design of large wind turbine blades of fibre composites (Phase 2) - Summary Report

Energy Technology Data Exchange (ETDEWEB)

Soerensen, B.F. [Risoe National Lab., Materials Research Dept., Roskilde (Denmark); Branner, K. [Risoe National Lab., Wind Energy Dept., Roskilde (Denmark); Stang, H. [Technical Univ. of Denmark, Dept. of Civil Engineering, Kgs. Lyngby (Denmark); Jensen, H.M. [Aalborg Univ., Dept. of Building Technology and Structural Engineering (Denmark); Lund, E. [Aalborg Univ., Inst. of Mechanical Enginering (Denmark); Jacobsen, T.K. [LM glasfiber A/S, Lunderskov (Denmark); Halling, K.M. [Vestas Wind Systems A/S, Ringkoebing (Denmark)

2005-08-01

The major results of Phase 2 of a project concerning the development of new design methods for wind turbine blades are summarised. Finite element models were used for studying the buckling behaviour of a box girder, tested to failure in Phase 1 of this project. The deformation behaviour of a box girder section subjected to transverse forces was investigated experimentally and by modelling. Buckling-driven delamination of planar specimens was studied on experimentally and by modelling. A novel approach was proposed for the determination of mixed mode cohesive laws for large-scale crack bridging problems. The normal and shear stresses of the cohesive laws were obtained from data of the fracture resistance and the normal and tangential displacements of the cohesive zone. Delamination of a thin layer bonded to an elastic substrate close to corners and edges was also analysed. Results for the shape of the interface crack front and critical stress for steady-state delamination were obtained. (au)

Analysis on Adhesively-Bonded Joints of FRP-steel Composite Bridge under Combined Loading : Arcan Test Study and Numerical Modeling

NARCIS (Netherlands)

Jiang, X.; Qiang, X.; Kolstein, M.H.; Bijlaard, F.S.K.

2016-01-01

The research presented in this paper is an experimental study and numerical analysis on mechanical behavior of the adhesively-bonded joint between FRP sandwich bridge deck and steel girder. Generally, there are three typical stress states in the adhesively-bonded joint: shear stress, tensile stress,

Damage Identification for Prestressed Adjacent Box-Beam Bridges

Directory of Open Access Journals (Sweden)

Kenneth K. Walsh

2014-01-01

Full Text Available Structural health monitoring (SHM has gained considerable attention as a tool for monitoring the health of civil infrastructure. For bridge infrastructure, previous methods have focused on the detection of localized damage through modal parameters extracted from the longitudinal direction of the structure. This paper investigates a new damage detection method based on the change in the first vertical mode extracted from the transverse direction of the bridge. The mode is determined through application of modal curve fitting to frequency response functions (FRFs that are formed using vertical response data obtained in the direction perpendicular to the bridge’s longitudinal axis. Using this method, both local damage and global damage in the bridge reveal themselves as having a localized effect on the bridge response. Furthermore, damage is revealed in such a way that it enables differentiation of the damage types. To demonstrate the effectiveness of the method, modal parameters were extracted from acceleration data obtained from a finite element model of a full bridge. Analysis of the modal parameters showed that the proposed approach could not only detect both local and global bridge damage, but could also differentiate between damage types using only one mode shape. The proposed method was compared to a previously developed SHM method.

Field vibration test of a long-span cable-stayed bridge by large exciters. Daishinpuku kashin ni yoru chodai shachokyo no jikkyo shindo jikken

Energy Technology Data Exchange (ETDEWEB)

Okauchi, I. (Chuo University, Tokyo (Japan). Faculty of Science and Engineering); Miyata, T. (Yokohama National University, Yokohama (Japan). Faculty of Engineering); Sasaki, N. (Mitsubishi Heavy Industries, Ltd., Tokyo (Japan)); Tatsumi, M.

1992-10-15

Long-span cable-stayed bridge requires indispensably discussions on safety against gale and earthquake, and correct assessment on its inherent vibration characteristics at the design stage is critical. However, theoretical assessment on structural decay is difficult, hence it is desirable to make measurement and verification upon its completion. This paper reports the result of measurements and considerations on a three-span continuous steel cable-stayed bridge with a length of 790 m (185 m + 420 m + 185 m) spanning between Hitsuishi Island and Iwakuro Island in the Kojima-Sakaide route of the Honshu-Shikoku connecting bridge. Large shaking machines were used to give girders vibrations with large amplitudes (10 cm at maximum), and high-accuracy measurements were made. The measurements verified the reasonability of the dynamic design for the bridge. The measured value of the logarithmic decay rate [delta] as the major experimental data presented that bending vibration is large as a whole, with torsional vibration somewhat smaller, and all the design values were on safety side. Confirmation was made on amplitude dependence of the decay rate, the inherent modes of low-order vibrations, and coupled behaviors among the girders, cables, and towers. 16 refs., 13 figs., 3 tabs.

Large scale testing of nitinol shape memory alloy devices for retrofitting of bridges

International Nuclear Information System (INIS)

Johnson, Rita; Emmanuel Maragakis, M; Saiid Saiidi, M; Padgett, Jamie E; DesRoches, Reginald

2008-01-01

A large scale testing program was conducted to determine the effects of shape memory alloy (SMA) restrainer cables on the seismic performance of in-span hinges of a representative multiple-frame concrete box girder bridge subjected to earthquake excitations. Another objective of the study was to compare the performance of SMA restrainers to that of traditional steel restrainers as restraining devices for reducing hinge displacement and the likelihood of collapse during earthquakes. The results of the tests show that SMA restrainers performed very well as restraining devices. The forces in the SMA and steel restrainers were comparable. However, the SMA restrainer cables had minimal residual strain after repeated loading and exhibited the ability to undergo many cycles with little strength and stiffness degradation. In addition, the hysteretic damping that was observed in the larger ground accelerations demonstrated the ability of the materials to dissipate energy. An analytical study was conducted to assess the anticipated seismic response of the test setup and evaluate the accuracy of the analytical model. The results of the analytical simulation illustrate that the analytical model was able to match the responses from the experimental tests, including peak stresses, strains, forces, and hinge openings

Design of pedestrian truss bridge with Sengon-Rubber laminated veneer lumber

Science.gov (United States)

Herbudiman, B.; Pranata, Y. A.; Pangestu, L.

2017-12-01

Timber bridges are one of the bridge that has long been used, but nowadays, large dimension of sawn timber has limited supply and also it is not environmental-friendly. Laminated veneer lumber (LVL) is a engineered wood that becomes one of the promising alternative, because it is made from lower quality wood that processed to be used as a more quality one. The bridge planned to be a pedestrian truss bridge with length of 9 m, width of 3 m, height of 2.5 m, and using bolt and steel plate as its connection system. Mechanical properties of LVL obtained directly from laboratory test result. Bridge modeling and planning for wood construction refers to SNI 7973:2013, while the loading refers to SNI 1725:2016. Based on the modelling and calculation, the dimension of truss frame and girder beam which are 9 cm x 9 cm and 9 cm x 18 cm have adequate strengths and satisfy deflection requirement.

Design and Construction of Operation Bridge for Research Reactor

International Nuclear Information System (INIS)

Jung, Kwangsub; Choi, Jinbok; Lee, Jongmin; Oh, Jinho

2015-01-01

The operation bridge contains a lower working deck mounted on a saddle that travels on rails. Upright members are mounted on the saddle to support the upper structure and two hoist monorails. The saddle contains an anti-derail system that is composed of seismic lugs and guide rollers. The operation bridge travels along the rails to transport the fuel assembly, irradiated object, and reactor components in the pools by using tools. Hoists are installed at the top girder. The hoist is suspended from the monorail by means of a motor driven trolley that runs along the monorail. Movements of hoist and trolley are controlled by using the control pendant switch. Processes of design and construction of the operation bridge for the research reactor are introduced. The operation bridge is designed under consideration of functions of handling equipment in the pool and operational limits for safety. Structural analysis is carried out to evaluate the structural integrity in the seismic events. Tests and inspections are also performed during fabrication and installation to confirm the function and safety of the operation bridge

Study and application of micrometric alignment on the prototype girders of the CLIC Two-Beam Module

CERN Document Server

Gazis, Nikolaos; Mainaud-Durand, Hélène; Samochkine, Alexandre; Anastasopoulos, Michail

2011-01-01

The Compact LInear Collider (CLIC), currently under study at CERN, aims at the development of a Multi-TeV e+ e- collider. The micro-precision CLIC RF-structures will have an accelerating gradient of 100 MV/m and will be mounted and aligned on specially developed supporting girders. The girder fabrication constraints are dictated by stringent physics requirements. The micrometric pre-alignment over several kilometers of girders, allow for the CLIC structures to fulfill their acceleration and collision functionality. Study of such girders and their sophisticated alignment method, is a challenging case involving dedicated mechanical design as well as prototype production and experimental testing.

Monitoring calculation of closure change of Extradosed Cable-stayed Bridge

Science.gov (United States)

Shi, Jing Xian; Ran, Zhi Hong

2018-06-01

During the construction of extradosed cable-stayed bridge in Yunnan province, China, the construction unit has made certain changes in the construction process of the closure section due to environmental restrictions: remove the hanging basket after the closure, the sling shall not be provided in closure section, the function of the sling is realized by the hanging basket on the 16th beam. In case of this change, the bridge has been constructed to section 15th. In order to ensure the smooth and orderly progress of each stage in the closure phase, this article is arranged according to the construction plan, appropriate adjustment of related procedures, checking the bridge safety at all stages of construction, the stress and force of the main girder are compared to ensure the safety of the construction after closure changes. Adjust the height of the beam of the 16th and 17th to adapt the new construction plan, and the bridge closure smoothly.

Design proposal for ultimate shear strength of tapered steel plate girders

Directory of Open Access Journals (Sweden)

A. Bedynek

2017-03-01

Full Text Available Numerous experimental and numerical studies on prismatic plate girders subjected to shear can be found in the literature. However, the real structures are frequently designed as non-uniform structural elements. The main objective of the research is the development of a new proposal for the calculation of the ultimate shear resistance of tapered steel plate girders taking into account the specific behaviour of such members. A new mechanical model is presented in the paper and it is used to show the differences between the behaviour of uniform and tapered web panels subjected to shear. EN 1993-1-5 design specifications for the determination of the shear strength for rectangular plates are improved in order to assess the shear strength of tapered elements. Numerical studies carried out on tapered steel plate girders subjected to shear lead to confirm the suitability of the mechanical model and the proposed design expression.

Committee VI.1. Extreme Hull Girder Loading

DEFF Research Database (Denmark)

Jensen, Jørgen Juncher

2000-01-01

Committee Mandate. Evaluate and develop direct calculation procedures for extreme wawe loads on ship hull girders. Due consideration shall be given to stochastic and non-linear effects. The procedures shall be assessed by comparison with in-service experiences, model tests and more refined...

FINITE ELEMENT ANALYSIS OF TAPERED COMPOSITE PLATE GIRDER WITH A NON-LINEAR VARYING WEB DEPTH

Directory of Open Access Journals (Sweden)

Q. A. HASAN

2017-11-01

Full Text Available The paper presents Finite Element Analysis to determine the ultimate shear capacity of tapered composite plate girder. The effect of degree of taper on the ultimate shear capacity of tapered steel-concrete composite plate girder with a nonlinear varying web depth, effect of slenderness ratio on the ultimate shear capacity, and effect of flange stiffness on the ductility were considered as the parametric studies. Effect of concrete slab on the ultimate shear capacity of tapered plate girders was also considered and it was found to be so effective on the ultimate shear capacity of the tapered plate girder compared with the steel one. The accuracy of the finite element method is established by comparing the finite element with the results existing in the literature. The study was conducted using nonlinear finite element modelling with computer software LUSAS 14.7.

Vehicle Signal Analysis Using Artificial Neural Networks for a Bridge Weigh-in-Motion System

Directory of Open Access Journals (Sweden)

Min-Seok Park

2009-10-01

Full Text Available This paper describes the procedures for development of signal analysis algorithms using artificial neural networks for Bridge Weigh-in-Motion (B-WIM systems. Through the analysis procedure, the extraction of information concerning heavy traffic vehicles such as weight, speed, and number of axles from the time domain strain data of the B-WIM system was attempted. As one of the several possible pattern recognition techniques, an Artificial Neural Network (ANN was employed since it could effectively include dynamic effects and bridge-vehicle interactions. A number of vehicle traveling experiments with sufficient load cases were executed on two different types of bridges, a simply supported pre-stressed concrete girder bridge and a cable-stayed bridge. Different types of WIM systems such as high-speed WIM or low-speed WIM were also utilized during the experiments for cross-checking and to validate the performance of the developed algorithms.

Vehicle Signal Analysis Using Artificial Neural Networks for a Bridge Weigh-in-Motion System.

Science.gov (United States)

Kim, Sungkon; Lee, Jungwhee; Park, Min-Seok; Jo, Byung-Wan

2009-01-01

This paper describes the procedures for development of signal analysis algorithms using artificial neural networks for Bridge Weigh-in-Motion (B-WIM) systems. Through the analysis procedure, the extraction of information concerning heavy traffic vehicles such as weight, speed, and number of axles from the time domain strain data of the B-WIM system was attempted. As one of the several possible pattern recognition techniques, an Artificial Neural Network (ANN) was employed since it could effectively include dynamic effects and bridge-vehicle interactions. A number of vehicle traveling experiments with sufficient load cases were executed on two different types of bridges, a simply supported pre-stressed concrete girder bridge and a cable-stayed bridge. Different types of WIM systems such as high-speed WIM or low-speed WIM were also utilized during the experiments for cross-checking and to validate the performance of the developed algorithms.

Bridges Dynamic Parameters Identification Based On Experimental and Numerical Method Comparison in Regard with Traffic Seismicity

Science.gov (United States)

Krkošková, Katarína; Papán, Daniel; Papánová, Zuzana

2017-10-01

The technical seismicity negatively affects the environment, buildings and structures. Technical seismicity means seismic shakes caused by force impulse, random process and unnatural origin. The vibration influence on buildings is evaluated in the Eurocode 8 in Slovak Republic, however, the Slovak Technical Standard STN 73 0036 includes solution of the technical seismicity. This standard also classes bridges into the group of structures that are significant in light of the technical seismicity - the group “U”. Using the case studies analysis by FEM simulation and comparison is necessary because of brief norm evaluation of this issue. In this article, determinate dynamic parameters by experimental measuring and numerical method on two real bridges are compared. First bridge, (D201 - 00) is Scaffold Bridge on the road I/11 leading to the city of Čadca and is situated in the city of Žilina. It is eleven - span concrete road bridge. The railway is the obstacle, which this bridge spans. Second bridge (M5973 Brodno) is situated in the part of Žilina City on the road of I/11. It is concrete three - span road bridge built as box girder. The computing part includes 3D computational models of the bridges. First bridge (D201 - 00) was modelled in the software of IDA Nexis as the slab - wall model. The model outputs are natural frequencies and natural vibration modes. Second bridge (M5973 Brodno) was modelled in the software of VisualFEA. The technical seismicity corresponds with the force impulse, which was put into this model. The model outputs are vibration displacements, velocities and accelerations. The aim of the experiments was measuring of the vibration acceleration time record of bridges, and there was need to systematic placement of accelerometers. The vibration acceleration time record is important during the under - bridge train crossing, about the first bridge (D201 - 00) and the vibration acceleration time domain is important during deducing the force

Dynamic response of a typical synchrotron magnet/girder assembly

International Nuclear Information System (INIS)

Jendrzejczyk, J.A.; Smith, R.K.; Vogt, M.E.

1993-06-01

In the Advanced Photon Source, the synchrotron booster ring accelerates positrons to the required energy level of 7 GeV. The positrons are then injected into the storage ring where they continue to orbit for 10--15 h. The storage ring quadrupoles have very stringent vibration criteria that must be satisfied to ensure that beam emittance growth is within acceptable limits, viz., <10%. Because the synchrotron booster ring is not operated after particle insertion into the storage ring, its vibration response is not a critical issue relative to the performance of the storage ring beam. Nevertheless, the synchrotron pulses at a frequency of 2 Hz, and if a vibration response frequency of the synchrotron magnet/girder assembly were to coincide with the pulsation frequency or its near harmonics, large-amplitude motion could result, with the effect that it could compromise the operation of the synchrotron. Due to the complex dynamics of the synchrotron magnet/girder assembly, it is necessary to measure the dynamic response of a prototypic assembly and its components to ensure that the inherent dynamic response frequencies are not equal to 2 Hz or any near harmonics. Dynamic-response measurement of the synchrotron girder assembly and component magnets is the subject of this report

Energy-based damping evaluation of cable-stayed bridges and its application to Tsurumi Tsubasa bridge; Shachokyo shindo gensui no energy teki hyokaho to Tsurumi Tsubasakyo eno tekiyo

Energy Technology Data Exchange (ETDEWEB)

Yamaguchi, H. [Saitama University, Saitama (Japan). Faculty of Engineering; Takano, H.; Ogasawara, M.; Shimosato, T. [Metropolitan Expressway Public Corp., Tokyo (Japan); Kato, M.; Kato, H. [NKK Corp., Tokyo (Japan)

1996-07-21

This paper provides and discusses a more common energy-based evaluation method of vibration damping in cable-stayed bridges. This method was applied to data obtained from the field vibration test of the Tsurumi Tsubasa Bridge. The damping was defined as dissipation energy in one cycle against the total potential energy. The dissipation energy from shoe friction, aerodynamic damping, and dampers for cables was added to the method proposed by Yamaguchi, et. al., in which the energy of girders, towers, and cables were quantitated, and the dissipation energy was determined from the loss factor of each constituent, to evaluate the damping of whole bridge. Thus, a more common energy-based evaluation method was provided. This method was applied to the damping obtained from the field vibration test of Tsurumi Tsubasa Bridge. Consequently, it was found that the damping of whole bridge was significantly affected by the shoe friction, aerodynamic damping, and dampers for cables. Distinguished damping characteristics of the Tsurumi Tsubasa Bridge could be explained by the energy-based evaluation. Validity of the energy-based evaluation method for damping of cable-stayed bridges was demonstrated. 15 refs., 9 figs., 6 tabs.

On the Influence of Hull Girder Flexibility on the Wave

DEFF Research Database (Denmark)

Seng, Sopheak; Andersen, Ingrid Marie Vincent; Jensen, Jørgen Juncher

2012-01-01

Numerical predictions and model test results of the wave induced bending moments in a 9,400 TEU post-Panamax container vessel are presented for two regular wave scenarios. Different numerical procedures have been applied: a linear and non-linear time-domain strip theory and a direct calculation (...... (CFD) solving the Navier-Stokes equations with the free surface captured by a volume-of-fluid (VOF) method. In all procedures the flexibility of the hull girder is modelled as a non-uniform Timoshenko beam. It is observed that the non-linear models agree well with the model tests...... and as there is no occurrence of severe slamming in the cases considered, the inexpensive non-linear strip theory is as accurate as the direct CFD calculation method. In a comparison with the results using the rigid body assumption, the increase in the vertical bending moment (VBM) amidships due to the flexibility of the hull...... girder is found to be approximately 7% (peak-to-peak amplitude) in general. The non-linear responses, however, contain over-harmonic frequencies which may coincide with the natural frequency of the two-node vertical bending mode inducing resonance. In that case the hull girder flexibility causes...

Development of a smart timber bridge girder with fiber optic sensors

Science.gov (United States)

James Wacker; Ursula Deza; Brent M. Phares; Terry J. Wipf

2010-01-01

Past timber bridge evaluation and maintenance efforts in the USA have principally focused on the internal integrity of timber components using various non-destructive evaluation tools to supplement visual inspection data. This project is part of a comprehensive effort to develop smart structure concepts for improving the long-term performance, maintenance, and...

Assessment of the transportation route of oversize and excessive loads in relation to the load-bearing capacity of existing bridges

Science.gov (United States)

Doležel, Jiří; Novák, Drahomír; Petrů, Jan

2017-09-01

Transportation routes of oversize and excessive loads are currently planned in relation to ensure the transit of a vehicle through critical points on the road. Critical points are level-intersection of roads, bridges etc. This article presents a comprehensive procedure to determine a reliability and a load-bearing capacity level of the existing bridges on highways and roads using the advanced methods of reliability analysis based on simulation techniques of Monte Carlo type in combination with nonlinear finite element method analysis. The safety index is considered as a main criterion of the reliability level of the existing construction structures and the index is described in current structural design standards, e.g. ISO and Eurocode. An example of a single-span slab bridge made of precast prestressed concrete girders of the 60 year current time and its load bearing capacity is set for the ultimate limit state and serviceability limit state. The structure’s design load capacity was estimated by the full probability nonlinear MKP analysis using a simulation technique Latin Hypercube Sampling (LHS). Load-bearing capacity values based on a fully probabilistic analysis are compared with the load-bearing capacity levels which were estimated by deterministic methods of a critical section of the most loaded girders.

A new multiconstraint method for determining the optimal cable stresses in cable-stayed bridges.

Science.gov (United States)

Asgari, B; Osman, S A; Adnan, A

2014-01-01

Cable-stayed bridges are one of the most popular types of long-span bridges. The structural behaviour of cable-stayed bridges is sensitive to the load distribution between the girder, pylons, and cables. The determination of pretensioning cable stresses is critical in the cable-stayed bridge design procedure. By finding the optimum stresses in cables, the load and moment distribution of the bridge can be improved. In recent years, different research works have studied iterative and modern methods to find optimum stresses of cables. However, most of the proposed methods have limitations in optimising the structural performance of cable-stayed bridges. This paper presents a multiconstraint optimisation method to specify the optimum cable forces in cable-stayed bridges. The proposed optimisation method produces less bending moments and stresses in the bridge members and requires shorter simulation time than other proposed methods. The results of comparative study show that the proposed method is more successful in restricting the deck and pylon displacements and providing uniform deck moment distribution than unit load method (ULM). The final design of cable-stayed bridges can be optimised considerably through proposed multiconstraint optimisation method.

A New Multiconstraint Method for Determining the Optimal Cable Stresses in Cable-Stayed Bridges

Directory of Open Access Journals (Sweden)

B. Asgari

2014-01-01

Full Text Available Cable-stayed bridges are one of the most popular types of long-span bridges. The structural behaviour of cable-stayed bridges is sensitive to the load distribution between the girder, pylons, and cables. The determination of pretensioning cable stresses is critical in the cable-stayed bridge design procedure. By finding the optimum stresses in cables, the load and moment distribution of the bridge can be improved. In recent years, different research works have studied iterative and modern methods to find optimum stresses of cables. However, most of the proposed methods have limitations in optimising the structural performance of cable-stayed bridges. This paper presents a multiconstraint optimisation method to specify the optimum cable forces in cable-stayed bridges. The proposed optimisation method produces less bending moments and stresses in the bridge members and requires shorter simulation time than other proposed methods. The results of comparative study show that the proposed method is more successful in restricting the deck and pylon displacements and providing uniform deck moment distribution than unit load method (ULM. The final design of cable-stayed bridges can be optimised considerably through proposed multiconstraint optimisation method.

Acoustic emission techniques applied to conventionally reinforced concrete bridge girders : final report.

Science.gov (United States)

2008-09-01

Reinforced concrete (RC) bridges generally operate at service-level loads except during discrete overload events that can reduce the integrity of the structure by initiating concrete cracks, widening or extending of existing concrete cracks, as well ...

Design of a Maglev Vibration Test Platform for the Research of Maglev Vehicle-girder Coupled Vibration Problem

Directory of Open Access Journals (Sweden)

Zhou Danfeng

2017-01-01

Full Text Available The maglev vehicle-girder coupled vibration problem has been encountered in many maglev test or commercial lines, which significantly degrade the performance of the maglev train. In previous research on the principle of the coupled vibration problem, it has been discovered that the fundamental model of the maglev girder can be simplified as a series of mass-spring resonators of different but related resonance frequencies, and that the stability of the vehicle-girder coupled system can be investigated by separately examining the stability of each mass-spring resonator – electromagnet coupled system. Based on this conclusion, a maglev test platform, which includes a single electromagnetic suspension control system, is built for experimental study of the coupled vibration problem. The guideway of the test platform is supported by a number of springs so as to change its flexibility. The mass of the guideway can also be changed by adjusting extra weights attached to it. By changing the flexibility and mass of the guideway, the rules of the maglev vehicle-girder coupled vibration problem are to be examined through experiments, and related theory on the vehicle-girder self-excited vibration proposed in previous research is also testified.

Quality control and in-service inspection technology for hybrid-composite girder bridges.

Science.gov (United States)

2014-08-01

This report describes efforts to develop quality control tools and in-service inspection technologies for the fabrication and construction of Hybrid Composite Beams (HCBs). HCBs are a new bridge technology currently being evaluated by the Missouri De...

Impact response of RC rock-shed girder with sand cushion under falling load

International Nuclear Information System (INIS)

Bhatti, Abdul Qadir; Kishi, Norimitsu

2010-01-01

Research highlights: → An applicability of FE model of RC girders with sand cushion has been investigated. → Experimental and numerical results of Impact force, reaction force and displacement have been performed. → Cracks obtained from numerical models are in good agreement with the experimental ones. → Reaction force-displacement loops agree well between numerical and experimental results. → The configuration of the hysteretic loop at failure of RC girders can be approximated by a parallelogram. - Abstract: In order to establish a proper finite element model of prototype RC girder with sand element for impact response analysis, dynamic response analysis of RC girders with sand cushion subjected to impact force due to weight falling from the height of H = 2.5, 5, 7.5 and 10 m was performed to improve the state of the art of protective design for real scale rock-sheds by using LS-DYNA code. An applicability of proposed model was discussed comparing with experimental results (e.g. impact force, reaction force and displacement waves). From this study, dynamic characteristics of impact response can be better simulated by using the proposed model. As a result, when the sand cushion was set up, the impact force, reaction force, mid-span displacement waves, distribution of reaction force-displacement loops, and crack patterns obtained from the numerical analysis are in good agreement with those from the experimental results.

Experimental Investigation of a Self-Sensing Hybrid GFRP-Concrete Bridge Superstructure with Embedded FBG Sensors

OpenAIRE

Wang, Yanlei; Li, Yunyu; Ran, Jianghua; Cao, Mingmin

2012-01-01

A self-sensing hybrid GFRP-concrete bridge superstructure, which consists of two bridge decks and each bridge deck is comprised of four GFRP box sections combined with a thin layer of concrete in the compression zone, was developed by using eight embedded FBG sensors in the top and bottom flanges of the four GFRP box sections at midspan section of one bridge deck along longitudinal direction, respectively. The proposed self-sensing hybrid bridge superstructure was tested in 4-point loading to...

Estimation of Structure-Borne Noise Reduction Effect of Steel Railway Bridge Equipped with Floating Ladder Track and Floating Reinforced-Concrete Deck

Science.gov (United States)

Watanabe, Tsutomu; Sogabe, Masamichi; Asanuma, Kiyoshi; Wakui, Hajime

A number of steel railway bridges have been constructed in Japan. Thin steel members used for the bridges easily tend to vibrate and generate structure-borne noise. Accordingly, the number of constructions of steel railway bridges tends to decrease in the urban areas from a viewpoint of environmental preservation. Then, as a countermeasure against structure-borne noise generated from steel railway bridges, we have developed a new type of the steel railway bridge equipped with a floating-ladder track and a floating reinforced-concrete (RC) deck. As a result of train-running experiment, it became apparent that the new steel railway bridge installed by double floating system has reduced a vibration velocity level by 10.5 dB(A) at main girder web as compared with a steel railway bridge installed by directly fastened track. This reduction effect was achieved by the ladder track and RC deck supported by resilient materials.

Application study on the first cable-stayed bridge with CFRP cables in China

Directory of Open Access Journals (Sweden)

Kuihua Mei

2015-08-01

Full Text Available In order to push forward the development of CFRP cable-stayed bridge and accumulate experiences, the study on the application of the first cable-stayed bridge with CFRP cables in China was carried out. The design essentials of main components of the bridge were introduced and its integral performances, including static properties, dynamic properties and seismic response were analyzed using finite element method. A new bond-type anchorage was developed and the processes of fabricating and installing CFRP cables were elaborated. Based on the results of construction simulation, a tension scheme for bridge was propound. During constructing, the stresses and displacement of girder and pylon, as well as the forces and stresses of cables, were tested. The results indicate that all sections of the bridge could meet the requirements of the ultimate bearing capacity and normal service; the performance of the anchorage is good and the stresses in each cable system are similar; the tested values accord well with the calculated values. Further, creep deformation of the resin in anchorages under service load is not obvious. All these results demonstrate that the first application of CFRP cables in the cable-stayed bridge in China is successful.

Bridge condition assessment based on long-term strain monitoring

Science.gov (United States)

Sun, LiMin; Sun, Shouwang

2011-04-01

In consideration of the important role that bridges play as transportation infrastructures, their safety, durability and serviceability have always been deeply concerned. Structural Health Monitoring Systems (SHMS) have been installed to many long-span bridges to provide bridge engineers with the information needed in making rational decisions for maintenance. However, SHMS also confronted bridge engineers with the challenge of efficient use of monitoring data. Thus, methodologies which are robust to random disturbance and sensitive to damage become a subject on which many researches in structural condition assessment concentrate. In this study, an innovative probabilistic approach for condition assessment of bridge structures was proposed on the basis of long-term strain monitoring on steel girder of a cable-stayed bridge. First, the methodology of damage detection in the vicinity of monitoring point using strain-based indices was investigated. Then, the composition of strain response of bridge under operational loads was analyzed. Thirdly, the influence of temperature and wind on strains was eliminated and thus strain fluctuation under vehicle loads is obtained. Finally, damage evolution assessment was carried out based on the statistical characteristics of rain-flow cycles derived from the strain fluctuation under vehicle loads. The research conducted indicates that the methodology proposed is qualified for structural condition assessment so far as the following respects are concerned: (a) capability of revealing structural deterioration; (b) immunity to the influence of environmental variation; (c) adaptability to the random characteristic exhibited by long-term monitoring data. Further examination of the applicability of the proposed methodology in aging bridge may provide a more convincing validation.

Low Cost Wireless Fatigue Crack Monitoring System Using RFID Arrays

Science.gov (United States)

2018-03-23

The use of welded steel cover plates had been a common design practice to increase beam section capacity in regions ofhigh torsion for decades. Many steel girder bridges with cover plates are still in service. Steel girder bridges are subject to cycl...

A numerical study on the structural integrity of self-anchored cable-stayed suspension bridges

Directory of Open Access Journals (Sweden)

Paolo Lonetti

2016-10-01

Full Text Available A generalized numerical model for predicting the structural integrity of self-anchored cable-stayed suspension bridges considering both geometric and material nonlinearities is proposed. The bridge is modeled by means of a 3D finite element approach based on a refined displacement-type finite element approximation, in which geometrical nonlinearities are assumed in all components of the structure. Moreover, nonlinearities produced by inelastic material and second order effects in the displacements are considered for girder and pylon elements, which combine gradual yielding theory with CRC tangent modulus concept. In addition, for the elements of the suspension system, i.e. stays, hangers and main cable, a finite plasticity theory is adopted to fully evaluate both geometric and material nonlinearities. In this framework, the influence of geometric and material nonlinearities on the collapse bridge behavior is investigated, by means of a comparative study, which identifies the effects produced on the ultimate bridge behavior of several sources of bridge nonlinearities involved in the bridge components. Results are developed with the purpose to evaluate numerically the influence of the material and geometric characteristics of self-anchored cable-stayed suspension bridges with respect also to conventional bridge based on cablestayed or suspension schemes

78 FR 52232 - 2013 Temporary Closure of I-65 (I-70/I-65 South Split Interchange) in the City of Indianapolis

Science.gov (United States)

2013-08-22

... southbound bridge girders and lowering the pavement section from south of Morris Street to north of Fletcher... immediately. FOR FURTHER INFORMATION CONTACT: Ms. Crystal Jones, Office of Freight Management and Operations..., which consists of replacing the northbound and southbound bridge girders and lowering the pavement...

Alignment and girder position of MSE septa in the new LSS4 extraction channel of the SPS

CERN Document Server

Balhan, B; Rizzo, A; Weterings, W; CERN. Geneva. SPS and LHC Division

2002-01-01

For the extraction of the beam from the Super Proton Synchrotron (SPS) to ring 2 of the Large Hadron Collider (LHC) and the CERN Neutrino to Gran Sasso (CNGS)facility, a new fast-extraction system is being constructed in the long straight section LSS4 of the SPS. Besides extraction bumpers, enlarged aperture quadrupoles and extraction kicker magnets (MKE), six conventional DC septum magnets (MSE) are used. These magnets are mounted on a single rigid support girder, pre-aligned so as to follow the trajectory of the extracted beam and optimise the available aperture. The girder has been motorised in order to optimise the local SPS aperture during setting up, so as to avoid the risk of circulating beam impact on the septum coils. In this note, we briefly present the trajectory and apertures of the beam, we describe the calculations and methods that have been used to determine the magnet position on the girder, and finally we report on the details of the girder movement and alignment.

Onboard monitoring of fatigue damage rates in the hull girder

DEFF Research Database (Denmark)

Nielsen, Ulrik Dam; Jensen, Jørgen Juncher; Pedersen, Preben Terndrup

2011-01-01

Most new advanced ships have extensive data collection systems to be used for continuous monitoring of engine and hull performance, for voyage performance evaluation etc. Such systems could be expanded to include also procedures for stress monitoring and for decision support, where the most...... critical wave-induced ship extreme responses and fatigue damage accumulation can be estimated for hypothetical changes in ship course and speed in the automatically estimated wave environment.The aim of this paper is to outline a calculation procedure for fatigue damage rate prediction in hull girders...... taking into account whipping stresses. It is conceptually shown how such a method, which integrates onboard estimation of sea states, can be used to deduce decision support with respect to the accumulated fatigue damage in the hull girder.The paper firstly presents a set of measured full-scale wave...

Structural health monitoring of the Gröndals Bridge in Sweden: the behaviour of CFRP strengthening in cold temperature

Science.gov (United States)

Hejll, Arvid; Täljsten, Björn; Carolin, Anders

2006-03-01

To obtain a better knowledge of existing structures behaviour monitoring can be used. The use of monitoring in bridge structures by the use of instruments to assess the integrity of structures is not new and there are reports from structures tested as early as in the 19th century according to ISIS Canada1 However, the term SHM (Structural Health Monitoring) is relatively new to civil engineering and the driving force to implement SHM comes from recognising the limitations of conventional visual inspections and evaluations using conservative codes of practice. The possibilities to monitor existing structures with help of the rapidly evolving Information Technology are to day carried out. The objective of SHM is to monitor the in-situ behaviour of a structure accurately and efficiently, to assess its performance under various service conditions, to detect damage or deterioration, and to determine the health or condition of the structure1. In Sweden strengthening and periodic monitoring of a large freivorbau bridge (pre-stresed concrete box girder bridge) has been carried out, the Gröndals Bridge. The bridge is located in Stockholm and is approximately 400 m in length with a free span of 120 m. It was opened to tram traffic in year 2000. Just after opening cracks were noticed in the webs, these cracks have then increased, the size of the largest cracks exceeded 0.5 mm, and at the end of year 2001 the bridge was temporarily strengthened. This was carried out with externally placed prestressed steel stays. The reason for cracking is quite clear but the responsibility is still debated. Nevertheless, it was evidently that the bridge needed to be strengthened. The strengthening methods used were CFRP plates in the Service Limit State (SLS) and prestressed dywidag stays in the Ultimate Limit State (ULS). The strengthening was carried out during year 2002. At the same time monitoring of the bridge commenced, using LVDT crack gauges as well as optical fibre sensors. This

Condition assessment and methods of abatement of prestressed concrete box-beam deterioration, phase II : volume 1.

Science.gov (United States)

2009-04-13

Side-by-side box-beam bridge constitutes approximately 17 percent of bridges built or replaced annually on : public roads and there is a renewed thrust to use this bridge type for rapid construction under the Highway for : LIFE program. Further, fail...

Condition assessment and methods of abatement of prestressed concrete box-beam deterioration, phase II : volume 2.

Science.gov (United States)

2009-04-13

Side-by-side box-beam bridge constitutes approximately 17 percent of bridges built or replaced annually on public roads and there is a renewed thrust to use this bridge type for rapid construction under the Highway for LIFE program. Further, failure ...

Acute subdural hematoma because of boxing.

Science.gov (United States)

Kushi, Hidehiko; Saito, Takeshi; Sakagami, Yuichiro; Ohtsuki, Jyoji; Tanjoh, Katsuhisa

2009-02-01

To identify factors determining the clinical characteristics and prognosis of acute subdural hematoma (ASDH) arising from boxing injuries by comparing with ASDH due to any nonboxing cause. Two groups were selected for this study: 10 patients with ASDH because of boxing injuries and 26 patients with nonboxer ASDH. All of the patients underwent neurologic examination by neurosurgeons. Primary resuscitation and stabilization as well as operative therapy were performed to all patients according to the European Brain Injury Consortium Guidelines. Two groups were compared in terms of age, the Glasgow Coma Scale at admission, neurologic findings, craniogram and brain computed tomography scan findings, operative findings, and prognosis. As potential prognostic indicators for boxers, the time interval until surgery, the Glasgow Outcome Scale, hematoma thickness, midline shift, and the site of bleeding were analyzed. The characteristics of patients because of boxing injuries are that patients were younger, had lucid interval, and had no cerebral contusion or contralateral brain injury. There was no significant difference in initial Glasgow Coma Scale, hematoma thickness, midline shift, and their prognosis. The most peculiar clinical presentation of boxers' ASDH was that all bleedings were limited from "bridging veins" or "cortical veins." The prognosis of boxers was most closely correlated with the site of bleeding (r2 = 0.81; p = 0.0001) and the midline shift (r2 = 0.67; p = 0.007). Our study shows that ASDH because of boxing is characterized by bleeding from bridging or cortical veins, and that the site of bleeding is a significant determinant of their prognosis.

Design, fabrication and erection of Queen Mall Bridge; Queen mall kyo no sekkei seisaku kasetsu

Energy Technology Data Exchange (ETDEWEB)

Arai, M.; Ishii, A.; Shinohara, T. [Sumitomo Heavy Industries, Ltd., Tokyo (Japan)

1997-12-20

This paper describes design, fabrication and erection of Queen Mall Bridge, which is a new landmark in Minato-Mirai Yokohama. This bridge is two-span continuous cable stayed pedestrian bridge with a roof, and has a length 72.2 m, a width 18 m and a weight about 1,050 t. This bridge connects between the Queen`s Square and the second floor of Pacifico Yokohama. Achieving harmonious impression of the newly designed bridge in this area, glass roof was employed and all-weld method was applied to the in-site jointing of main girders and main tower in addition to the essential structural design. Since all-weld method was applied to the in-site jointing, highly accurate fabrication was considered during the in-site jointing. Due to the heavy traffic of the road below the bridge, the erection time was shortened under the severe erection conditions at night by large block method. Especially, accuracy control was considered for the whole shape management. Pre-assemble of all members was conducted just near the erection site, only 500 m away from the site, to shorten the construction time. 1 ref., 5 figs.

Vibration analysis of concrete bridges during a train pass-by using various models

International Nuclear Information System (INIS)

Li, Qi; Wang, Ke; Cheng, Shili; Li, Wuqian; Song, Xiaodong

2016-01-01

The vibration of a bridge must be determined in order to predict the bridge noise during a train pass-by. It can be generally solved with different models either in the time domain or the frequency domain. The computation cost and accuracy of these models vary a lot in a wide frequency band. This study aims to compare the results obtained from various models for recommending the most suitable model in further noise prediction. First, train-track-bridge models in the time domain are developed by using the finite element method and mode superposition method. The rails are modeled by Timoshenko beam elements and the bridge is respectively modeled by shell elements and volume elements. Second, power flow models for the coupled system are established in the frequency domain. The rails are modelled by infinite Timoshenko beams and the bridge is respectively represented by three finite element models, an infinite Kirchhoff plate, and an infinite Mindlin plate model. The vibration at given locations of the bridge and the power input to the bridges through the rail fasteners are calculated using these models. The results show that the shear deformation of the bridge deck has significant influences on the bridge vibration at medium-to-high frequencies. The Mindlin plate model can be used to represent the U-shaped girder to obtain the power input to the bridge with high accuracy and efficiency. (paper)

FIP Symposium 1997 (South Africa); FIP Symposium 1997 (Minami Africa) ni sankashite

Energy Technology Data Exchange (ETDEWEB)

Niwano, T. [Oriental Construction Co. Ltd., Tokyo (Japan); Shinagawa, K.; Takahashi, T.

1997-07-31

FIP (Federation Internationale de la Precontrainte) Symposium was held in Johannesburg, South Africa. Ikeda and others were sent by the Japan Prestressed Concrete Engineering Association to participate the symposium and visit some bridges in Hong Kong and South Africa. As the keynote addresses, the trends of PC in South Africa, Europe, America, East Asia and Australia was reported. Japanese papers among 105 presented papers are as follows: Iwasaki`s `Construction method of the railway PC skew slab bridge, Natori-Gawa bridge`, Toda`s `Construction of the suspended slab bridge longest in the world, Yume Tsuri-bashi`, Iizuka`s `Experiment on earthquake characteristics of precast concrete columns` and Sugita`s `Study on concrete using high-activity rice hull ash`. The group visited Kap Shui Mun bridge (Hong Kong) of 750m long constructed by Japanese JV which is the 5-span continuous complex cable stayed bridge, and featured by PC box girder structure of side spans. The group also visited Gouritz River PC bridge in South Africa. 5 refs., 10 figs.

Modal analysis of railway bridge hangers using artificial and ambient excitation

Science.gov (United States)

Link, M.; Weiland, M.; Yu, F.

2002-12-01

This paper describes the methods used and results obtained from analysing some resonance phenomena which were observed on a steel railway bridge. These phenomena were visible on the slender hangers connecting the arch girder and the main truss girder under certain wind conditions. The paper describes the set up of a vibration monitoring system designed to measure the vibration response of the hangers together with the wind velocity and the wind direction over a period of several months under operational conditions. These data should yield the basis for correlating the wind and the structural characteristics. In addition artificial impulse hammer excitation was used to measure the modal characteristics (natural frequencies and modes of the hangers separately. The results of these tests compared well with those obtained from applying some “output only" modal identification techniques to the operational response data with unknown excitation forces. The results also compared well to analytical predictions and were used to identify the axial forces in the hangers by updating the axial force minimising the test/analysis deviations. The results allowed to estimate the fatigue life of the hangers confirming the need for the design of anti- vibration devices.

Discussion on design and stress checking of cast-in-place bracket

Science.gov (United States)

Xi, Tang Xian; Yong, He; Hu, Sun Shuan

2018-04-01

The cast-in-place bracket is the main support structure in the construction of bridge. Its strength, stiffness and stability have a direct impact on the quality and the safety of bridge construction. The design and calculation of the bracket in the prestressed concrete box girder are analyzed in this paper. The models including Bailey beam, steel crossbeam and steel columns are established by the finite element software. The strength, stiffness and stability of each model under the most unfavorable load are analyzed by MIDAS Civil. The analysis results verify that the support plan meets the relevant specifications and construction requirements. The feasibility of the support scheme was verified well accordingly. The paper can provide reference and guidance for similar engineering construction.

Fatigue analysis and life prediction of composite highway bridge decks under traffic loading

Directory of Open Access Journals (Sweden)

Fernando N. Leitão

Full Text Available Steel and composite (steel-concrete highway bridges are currently subjected to dynamic actions of variable magnitude due to convoy of vehicles crossing on the deck pavement. These dynamic actions can generate the nucleation of fractures or even their propagation on the bridge deck structure. Proper consideration of all of the aspects mentioned pointed our team to develop an analysis methodology with emphasis to evaluate the stresses through a dynamic analysis of highway bridge decks including the action of vehicles. The design codes recommend the application of the curves S-N associated to the Miner's damage rule to evaluate the fatigue and service life of steel and composite (steel-concrete bridges. In this work, the developed computational model adopted the usual mesh refinement techniques present in finite element method simulations implemented in the ANSYS program. The investigated highway bridge is constituted by four longitudinal composite girders and a concrete deck, spanning 40.0m by 13.5m. The analysis methodology and procedures presented in the design codes were applied to evaluate the fatigue of the bridge determining the service life of the structure. The main conclusions of this investigation focused on alerting structural engineers to the possible distortions, associated to the steel and composite bridge's service life when subjected to vehicle's dynamic actions.

Intelligente Bauwerke

DEFF Research Database (Denmark)

Schneider, Ronald; Fischer, Johannes; Straub, Daniel

girder is formed. This approach accounts for structural redundancies of the continuous box girder with respect to its plastic cross-sectional capacity and its static indeterminacy. To prove the concept, a software prototype has been developed which couples an easy-to-use graphical user interface (front-end......) with a computational engine (back-end). The current version of the prototype implements a model of chloride-induced reinforcement corrosion and a structural model which performs the plastic limit analysis for determining the ultimate capacity of the box girder on the basis of a finite element model. The prototype...

Container crane for sea freight containers

NARCIS (Netherlands)

Luttekes, E.; Rijsenbrij, J.C.

2001-01-01

The invention relates to a container crane for loading and unloading seaborne containers. The container crane comprises a bridge girder (7), a jib (8), at least two crabs (11, 12) which can travel along the said bridge girder and/or jib and are provided with hoist means for lifting and lowering the

Proposal of self-anchored cable-supported bridge with main span length of 500m; Chuo span 500m kibo no jiteishiki tsurigatashiki kyoryo ni kansuru teian

Energy Technology Data Exchange (ETDEWEB)

Fukasawa, Y.; Sugiyama, T. [Yamaguchi University, Yamaguchi (Japan). Faculty of Engineering; Kaneko, S.; Mukoyama, T.; Iwaki, T. [Pacific Consultants K.K., Tokyo (Japan)

1995-12-15

In order to investigate the feasibility of construction of cable-supported bridge at the site where ground condition is poor and/or air route restriction shoed be considered the static and dynamic characteristics of both self-anchored cable-stayed bridge with relatively low tower and self-anchored suspension bridge have been discussed. The main span length of bridge considered here is about 500 m because of the fact that stress resultant of main girder caused by design loads is considerably lower than its design strength in the existing cable-supported bridges of this scale. The result shows that the application of both types of cable-supported bridges to the above described site may be possible as enough static safety and economy are ensured. It has been also revealed that no problem may occur from both wind and earthquake resistant viewpoints. 10 refs., 24 figs., 8 tabs.

Ultimate strength of a large wind turbine blade

DEFF Research Database (Denmark)

Jensen, Find Mølholt

2009-01-01

reinforcements helping to prevent undesired structural elastic mechanisms are presented. The functionality of two of the suggested structural reinforcements was demonstrated in full-scale tests and the rest trough FE-studies. The blade design under investigation consisted of an aerodynamic airfoil and a load...... carrying box girder. In total, five full-scale tests have been performed involving one complete blade and two shortened box girders. The second box girder was submitted to three independent tests covering different structural reinforcement alternatives. The advantages and disadvantages of testing......The present PhD project contains a study of the structural static strength of wind turbine blades loaded in flap-wise direction. A combination of experimental and numerical work has been used to address the most critical failure mechanisms and to get an understanding of the complex structural...

Post-buckling capacity of bi-axially loaded rectangular steel plates

DEFF Research Database (Denmark)

Jönsson, Jeppe; Bondum, T. H.

2012-01-01

slenderness and edge displacement ratio are included in the investigations presented. Capacity interaction curves are established in the bi-axial stress domain. It turns out that for certain stress ratios the imperfections dominating the ultimate capacity are not affine to the lowest classical buckling mode...... for biaxial stress. It is of great interest that short wave imperfections of a lower magnitude compared to conventionally used imperfections are seen to lower the capacity of the bi-axially loaded plates. The topic is of major concern in the flange plates of long span bridges with multi box girder...

Use and selection of bridges as day roosts by Rafinesque's Big Eared Bats.

Energy Technology Data Exchange (ETDEWEB)

Bennett, Frances, M.; Loeb, Susan, C.; Bunch, Mary, S.; Bowerman, William, W.

2008-03-01

ABSTRACT.—Rafinesque’s big-eared bats (Corynorhinus rafinesquii) use bridges as day roosts in parts of their range, but information on bridge use across their range is lacking. From May to Aug. 2002 we surveyed 1129 bridges (12.5%) within all 46 counties of South Carolina to determine use and selection of bridges as day roosts by big-eared bats and to document their distribution across the state. During summer 2003, we visited 235 bridges in previously occupied areas of the state to evaluate short-term fidelity to bridge roosts. We found colonies and solitary big-eared bats beneath 38 bridges in 2002 and 54 bridges in 2003. Construction type and size of bridges strongly influenced use in both years; bats selected large, concrete girder bridges and avoided flat-bottomed slab bridges. The majority of occupied bridges (94.7%) were in the Upper and Lower Coastal Plains, but a few bridges (5.3%) were located in the Piedmont. Rafinesque’s big-eared bats were absent beneath bridges in the Blue Ridge Mountains. We established new records of occurrence for 10 counties. In the Coastal Plains, big-eared bats exhibited a high degree of short-term fidelity to roosts in highway bridges. For bridges that were occupied at least once, mean frequency of use was 65.9%. Probability of finding bats under a bridge ranged from 0.46 to 0.73 depending on whether the bridge was occupied in the previous year. Thus, bridges should be inspected three to five times in a given year to determine whether they are being used. Regional bridge roost surveys may be a good method for determining the distribution of C. rafinesquii, particularly in the Coastal Plains, and protection of suitable bridges may be a viable conservation strategy where natural roost sites are limited.

Increasing the Capacity of Existing Bridges by Using Unbonded Prestressing Technology: A Case Study

Directory of Open Access Journals (Sweden)

Antonino Recupero

2014-01-01

Full Text Available External posttensioning or unbonded prestressing was found to be a powerful tool for retrofitting and for increasing the life extension of existing structures. Since the 1950s, this technique of reinforcement was applied with success to bridge structures in many countries, and was found to provide an efficient and economic solution for a wide range of bridge types and conditions. Unbonded prestressing is defined as a system in which the post-tensioning tendons or bars are located outside the concrete cross-section and the prestressing forces are transmitted to the girder through the end anchorages, deviators, or saddles. In response to the demand for a faster and more efficient transportation system, there was a steady increase in the weight and volume of traffic throughout the world. Besides increases in legal vehicle loads, the overloading of vehicles is a common problem and it must also be considered when designing or assessing bridges. As a result, many bridges are now required to carry loads significantly greater than their original design loads; and their deck results still deteriorated by cracking of concrete, corrosion of rebars, snapping of tendons, and so forth. In the following, a case study about a railway bridge retrofitted by external posttensioning technique will be illustrated.

Comportamiento estructural y criterios de diseño de los puentes extradosados: visión general y estado del arte Structural behavior and design criteria of extradosed bridges: general insight and state of the art

Directory of Open Access Journals (Sweden)

José Benjumea

2010-01-01

Full Text Available Durante los últimos 10 años, los puentes extradosados se han convertido en una solución estructural atractiva alrededor del mundo, gracias a los buenos resultados obtenidos con las primeras realizaciones en Japón. Esta nueva tipología, reconocida generalmente como una solución intermedia entre los puentes atirantados y los de pretensado de viga cajón construidos por voladizos sucesivos, se ha convertido en una opción interesante. Por consiguiente, dado el interés que hoy en día existe alrededor de este tipo de puente, en este trabajo se presenta el contexto histórico que describe su origen, y se exponen la influencia de los principales elementos estructurales en el comportamiento del puente, y los criterios de diseño que han sido propuestos por investigadores en el tema. De esta manera, se espera ofrecer una visión general de la concepción y el comportamiento estructural de los puentes extradosados para que sea considerada una alternativa más de tipología estructural de puentes en nuestro medio.Over the past 10 years, Extradosed bridges have become an attractive structural type around the world, due to the good results obtained with the first bridges constructed in Japan. This new typology, generally recognized as an intermediate solution between cable stayed bridges and cantilever constructed prestressed box-girder bridges, because these take advantages of design and constructions methods of the other two typologies, has become an interesting option. Therefore, given the interest that exist about this type of bridge, in this paper the historical context that describes its origin, the influence of the principal structural elements and the design criteria proposed by researchers are presented. In this way it is expected to offer a general insight into the design conception and structural behavior of Extradosed Bridges, so that they may be considered as an alternative structure for bridges in the Americas.

Economic impact of multi-span, prestressed concrete girder bridges designed as simple span versus continuous span : final report.

Science.gov (United States)

2016-10-01

The objective of this study was to determine the economic impact of designing pre-tensioned prestressed concrete beam (PPCB) : bridges utilizing the continuity developed in the bridge deck as opposed to the current Iowa Department of Transportation (...

Simulation Study on Train-Induced Vibration Control of a Long-Span Steel Truss Girder Bridge by Tuned Mass Dampers

Directory of Open Access Journals (Sweden)

Hao Wang

2014-01-01

Full Text Available Train-induced vibration of steel truss bridges is one of the key issues in bridge engineering. This paper talks about the application of tuned mass damper (TMD on the vibration control of a steel truss bridge subjected to dynamic train loads. The Nanjing Yangtze River Bridge (NYRB is taken as the research object and a recorded typical train load is included in this study. With dynamic finite element (FE method, the real-time dynamic responses of NYRB are analyzed based on a simplified train-bridge time-varying system. Thereinto, two cases including single train moving at one side and two trains moving oppositely are specifically investigated. According to the dynamic characteristics and dynamic responses of NYRB, the fourth vertical bending mode is selected as the control target and the parameter sensitivity analysis on vibration control efficiency with TMD is conducted. Using the first-order optimization method, the optimal parameters of TMD are then acquired with the control efficiency of TMD, the static displacement of Midspan, expenditure of TMDs, and manufacture difficulty of the damper considered. Results obtained in this study can provide references for the vibration control of steel truss bridges.

STUDY, EVALUATION AND TEST OF SUBMODULE TO GIRDER BOLTED JOINT

CERN Document Server

Blocki, J; Miralles, Ll; Topilin, N D

2000-01-01

The object of the present work is to study the bolted joint submodule to girder. This joint is critical from the point of view of the mechanical integrity of the Tilecal Barrel and Extended Barrel modules and LAr Endcaps. Theoretical analysis, FEM calculations and tests have been carried out in order to find a solution that fulfils the safety factors design criteria.

Research on Fluid Viscous Damper Parameters of Cable-Stayed Bridge in Northwest China

Directory of Open Access Journals (Sweden)

Xiongjun He

2017-01-01

Full Text Available To optimize the aseismic performance of nonlinear fluid viscous dampers (FVD of cable-stayed bridge in the highly seismic zone, Xigu Yellow River Bridge in northwest China is taken as an example. Nonlinear time-history analysis method is used to research on the relation among the internal forces, displacements, and damping parameters of the 650 tonnage FVD. The method of getting the minimum of binary functions is used to obtain the optimal parameters of FVD. Also, the 1 : 1 full-scale FVD model is made and used in the constitutive relation test. Then the test result of the damping parameters can be got by normal equation method. The optimized method to obtain the damping parameters is further verified. The results indicate that seismic response in key positions of the cable-stayed bridge can be reduced by installing longitudinal nonlinear FVD between the towers and girders if choosing reasonable damping parameters C and ξ. The optimal damping parameters can be calculated accurately by the proposed method of optimizing damping parameters of nonlinear FVD, and the constitutive relation test verifies the correctness of the optimization analysis method. Conclusions concerned can be applied to the design of nonlinear FVD for cable-stayed bridges.

Drift tube suspension for high intensity linear accelerators

International Nuclear Information System (INIS)

Clark, D.C.; Frank, J.A.; Liska, D.J.; Potter, R.C.; Schamaun, R.G.

1982-01-01

The disclosure relates to a drift tube suspension for high intensity linear accelerators. The system comprises a series of box-sections girders independently adjustably mounted on a linear accelerator. A plurality of drift tube holding stems are individually adjustably mounted on each girder

Drift tube suspension for high intensity linear accelerators

Science.gov (United States)

Liska, Donald J.; Schamaun, Roger G.; Clark, Donald C.; Potter, R. Christopher; Frank, Joseph A.

1982-01-01

The disclosure relates to a drift tube suspension for high intensity linear accelerators. The system comprises a series of box-sections girders independently adjustably mounted on a linear accelerator. A plurality of drift tube holding stems are individually adjustably mounted on each girder.

Environmental impact assessment and eco-friendly decision-making in civil structures.

Science.gov (United States)

Kim, Sang-Hyo; Choi, Moon-Seock; Mha, Ho-Seong; Joung, Jung-Yeun

2013-09-15

This study develops two useful procedures in performing an environmental-impact assessment. One is the advanced life-cycle assessment (LCA) method, which effectively tracks the flow of materials and considers the recycling and demolition of a civil structure. The other is an eco-friendly decision-making procedure, which may effectively apply when determining the prototype of a civil structure. The advanced LCA method differs from traditional LCA procedure, as it classifies the input material prior to the impact assessment. Classification work is performed to establish independent life-cycle stages for each material. The processes of recycling and demolition are appropriately added to the life-cycle stages. The impact assessment is performed separately for the materials, and results are aggregated at the end of the analysis. The eco-friendly decision-making procedure enables designers to choose an economical, and environmentally friendly, alternative during the planning phase of the construction project. This procedure rationally amalgamates economical value and environmental effects into a single indicator. The life cycle cost (LCC) of a structure can be analysed by using conventional LCC tools, whereas the environmental impact is estimated by LCA. The results from LCC and LCA are then integrated by using either a CO2 conversion method or an analytical hierarchy process (AHP). The CO2 conversion method presents the result as a monetary value, whereas the AHP presents the result as a non-dimensional value. A practical example using a steel box girder bridge and a pre-stressed concrete (PSC) box-girder bridge is also given in order to aid the understanding of the presented procedure. Copyright © 2013 Elsevier Ltd. All rights reserved.

Static and fatigue investigation of second generation steel free bridge decks

International Nuclear Information System (INIS)

Klowak, C.; Memon, Amjad H.; Mufti, Aftab A.

2006-01-01

This paper outlines the static and fatigue behavior of two different cast-in-place second generation steel-free bridge decks, which are: hybrid carbon fiber reinforced polymer (CFRP); and glass fiber reinforced polymer (GFRP) and steel strap design. Although cast monolithically, the first deck slab was divided into three segments with different reinforcement configurations. All three segments were tested under a 222kN cyclic loading to investigate fatigue behavior. The second bridge deck comprised an internal panel and two cantilevers and was equipped with a civionics system. The internal panel static test that this paper deals with is useful in the development of fatigue theory derived from fatigue testing of the first bridge deck. Test results form the cyclic loading of the first bridge deck indicated that the cross-sectional area of the reinforcement used in the test bridge deck can be reduced by 40% based on the reinforcement provided in the deck under service loads. The hybrid system also reduced the development of longitudinal crack widths to approximately 0.4 mm under service conditions, compared to the cracks that occurred approximately halfway between adjacent bridge girders that were determined to be roughly 1 mm in several first generation steel-free bridge decks constructed in Canada. Civionics, also discussed in the paper, is a new term coined from Civil-Electronics, which is the application of electronics to civil structures. The Civionics Specifications (2004) developed by ISIS Canada researchers are a helpful design tool for engineers and contractors to develop civionics and structural health monitoring systems for civil infrastructure that will last the lifetime of a structure. The use of civionics for the second test bridge deck ensured the survival of 100% of the 63 internal sensors throughout the rigors of the construction and casting of the deck. (author)

A FULL-SCALE MEASUREMENT OF WIND ACTIONS AND EFFECTS ON A SEA-CROSSING BRIDGE

Directory of Open Access Journals (Sweden)

Yi Zhou

2017-10-01

Full Text Available Wind loading is critical for the large-span and light-weight structures, and field measurement is the most effective way to evaluate the wind resistance performance of a specific structure. This study investigates the wind characteristics and wind-induced vibration on a sea-crossing bridge in China, namely Donghai Bridge, based on up to six years of monitoring data. It is found that: (1 there exists obvious discrepancy between the measured wind field parameters and the values suggested by the design code; and the wind records at the bridge site is easily interfered by the bridge structure itself, which should be considered in interpreting the measurements and designing structural health monitoring systems (SHMS; (2 for strong winds with high non-stationarity, a shorter averaging time than 10-min is preferable to obtain more stable turbulent wind characteristics; (3 the root mean square (RMS of the wind-induced acceleration of the girder may increase in an approximately quadratic curve relationship with the mean wind speed; and (4 compared to traffic load, the wind dominates the girder’s lateral vibration amplitude, while the heavy-load traffic might exert more influence on the girder’s vertical and torsional vibrations than the high winds. This study provides field evidence for the wind-resistant design and evaluation of bridges in similar operational conditions.

Assessing Static Performance of the Dashengguan Yangtze Bridge by Monitoring the Correlation between Temperature Field and Its Static Strains

Directory of Open Access Journals (Sweden)

Gao-Xin Wang

2015-01-01

Full Text Available Taking advantage of the structural health monitoring system installed on the steel truss arch girder of Dashengguan Yangtze Bridge, the temperature field data and static strain data are collected and analyzed for the static performance assessment of the bridge. Through analysis, it is found that the static strain changes are mainly caused by temperature field (temperature and temperature difference and train. After the train-induced static strains are removed, the correlation between the remaining static strains and the temperature field shows apparent linear characteristics, which can be mathematically modeled for the description of static performance. Therefore, multivariate linear regression function combined with principal component analysis is introduced to mathematically model the correlation. Furthermore, the residual static strains of mathematical model are adopted as assessment indicator and three kinds of degradation regulations of static performance are obtained after simulation of the residual static strains. Finally, it is concluded that the static performance of Dashengguan Yangtze Bridge was in a good condition during that period.

Experiments and theory on deck and girder crushing

DEFF Research Database (Denmark)

Simonsen, Bo Cerup; Ocakli, Hasan

1999-01-01

-deflection curves and modes of deformation for decks, stringer decks and deep thin-walled beams subjected to central or excentric point loads between transverse frames. Based on theory and experiments, various modelling aspects of the local/global failure of the beams are discussed. The agreement between......This paper is concerned with theoretical and experimental analysis of deep plastic collapse of a deck or deep girder subjected to an in-plane, concentrated load. A theory is derived which is valid until initition of fracture in the structure. The presented experimental results show load...

Prestressing Concrete with CFRP Composites for Sustainability and Corrosion-Free Applications

Directory of Open Access Journals (Sweden)

Belarbi A.

2018-01-01

Full Text Available Advancement in material science has enabled the engineers to enhance the strength and long-term behavior of concrete structures. The conventional approach is to use steel for prestressed bridge girders. Despite having good ductility and strength, beams prestressed with steel are susceptible to corrosion when subjected to environmental exposure. The corrosion of the prestressing steel reduces load carrying capacity of the prestressed member and result in catastrophic failures. In the last decades, more durable composite materials such as Aramid Fiber Reinforced Polymer (AFRP, Glass Fiber Reinforced Polymer (GFRP and Carbon Fiber Reinforced Polymer (CFRP have been implemented in concrete structures as a solution to this problem. Among these materials, CFRP stands out as a primary prestressing reinforcement, which has the potential to replace steel and provide corrosion free prestressed bridge girders. Despite its promise, prestressing CFRP has not frequently been used for bridge construction worldwide. The major contributing factor to the lack of advancement of this promising technology in the United States (U.S. is the lack of comprehensive design specifications. Apart from a limited number of guides, manuals, and commentaries, there is currently no standard or comprehensive design guideline available to bridge engineers in the U.S. for the design of concrete structures prestressed with CFRP systems. The main goal is to develop design guidelines in AASHTO-LRFD format for concrete bridge girders with prestressing CFRP materials. The guidelines are intended to address the limitation in current AASHTO-LRFD Bridge Design Specifications which is applicable for prestressed bridge girders with steel strands. To accomplish this goal, some of the critical parameters that affect the design and long-term behavior of prestressed concrete bridge girders with prestressing CFRP systems are identified and included in the research work. This paper presents

Sensitivity and statistical analysis within the elaboration of steel plated girder resistance

Czech Academy of Sciences Publication Activity Database

Melcher, J.; Škaloud, Miroslav; Kala, Z.; Karmazínová, M.

2009-01-01

Roč. 5, č. 2 (2009), s. 120-126 ISSN 1816-112X. [International conf. on steel and aluminium structures /6./. Oxford, 24.06.2007-27.06.2007] Institutional research plan: CEZ:AV0Z20710524 Keywords : steel structures * fatigue * sensitivity * imperfection * plated girder Subject RIV: JM - Building Engineering

Economic impact of multi-span, prestressed concrete girder bridges designed as simple span versus continuous span : tech transfer summary.

Science.gov (United States)

2016-10-01

The objective of this study was to determine the economic impact of : designing pre-tensioned prestressed concrete beam (PPCB) bridges : utilizing the continuity developed in the bridge deck as opposed to the : current Iowa Department of Transportati...

Investigating the impact of non-linear geometrical effects on wind turbine blades—Part 1: Current status of design and test methods and future challenges in design optimization

DEFF Research Database (Denmark)

Jensen, Find Mølholt; Puri, Amit S.; Dear, John P.

2011-01-01

This article is the first part of a three-article series and it deals with full-scale tests of a load-carrying box girder. The two other articles present more details on smaller sub-component levels as well as cap specimens (article 2) and shear webs (article 3). This article also links to the two...... may also have a significant impact on present wind turbine blades. In this article, a 34 m long load-carrying box girder has been tested in static flap-wise bending, and it has been demonstrated that, for this design, the Brazier effect is a critical phenomenon of great relevance for the ultimate...... failure strength. The box girder has been evaluated with and without a cap (wire) reinforcement. The cap reinforcement is one out of seven inventions Risø DTU published in 2008, which are all intended to result in a lighter and more reliable blade design. Copyright © 2010 John Wiley & Sons, Ltd....

Numerical Simulation of Vertical Random Vibration of Train-Slab Track-Bridge Interaction System by PEM

Directory of Open Access Journals (Sweden)

Zhi-ping Zeng

2014-01-01

Full Text Available The paper describes the numerical simulation of the vertical random vibration of train-slab track-bridge interaction system by means of finite element method and pseudoexcitation method. Each vehicle is modeled as four-wheelset mass-spring-damper system with two-layer suspension systems. The rail, slab, and bridge girder are modeled by three-layer elastic Bernoulli-Euler beams connected with each other by spring and damper elements. The equations of motion for the entire system are derived according to energy principle. By regarding rail irregularity as a series of multipoint, different-phase random excitations, the random load vectors of the equations of motion are obtained by pseudoexcitation method. Taking a nine-span simply supported beam bridge traveled by a train consisting of 8 vehicles as an example, the vertical random vibration responses of the system are investigated. Firstly, the suitable number of discrete frequencies of rail irregularity is obtained by numerical experimentations. Secondly, the reliability and efficiency of pseudoexcitation method are verified through comparison with Monte Carlo method. Thirdly, the random vibration characteristics of train-slab track-bridge interaction system are analyzed by pseudoexcitation method. Finally, applying the 3σ rule for Gaussian stochastic process, the maximum responses of train-slab track-bridge interaction system with respect to various train speeds are studied.

Stochastic Thermodynamics of a Particle in a Box.

Science.gov (United States)

Gong, Zongping; Lan, Yueheng; Quan, H T

2016-10-28

The piston system (particles in a box) is the simplest paradigmatic model in traditional thermodynamics. However, the recently established framework of stochastic thermodynamics (ST) fails to apply to this model system due to the embedded singularity in the potential. In this Letter, we study the ST of a particle in a box by adopting a novel coordinate transformation technique. Through comparing with the exact solution of a breathing harmonic oscillator, we obtain analytical results of work distribution for an arbitrary protocol in the linear response regime and verify various predictions of the fluctuation-dissipation relation. When applying to the Brownian Szilard engine model, we obtain the optimal protocol λ_{t}=λ_{0}2^{t/τ} for a given sufficiently long total time τ. Our study not only establishes a paradigm for studying ST of a particle in a box but also bridges the long-standing gap in the development of ST.

Magnetic-based NDE of steel in prestressed and post-tensioned concrete bridges

Science.gov (United States)

Ghorbanpoor, Al

1998-03-01

This paper addresses a study, funded by the Federal Highway Administration (FHWA), the U.S. Department of Transportation (DOT), that is currently underway at the University of Wisconsin-Milwaukee. The objective of the study is to develop an automated non-destructive testing system based on the magnetic flux leakage principle that would allow assessment of the condition of reinforcing and prestressing steels in concrete bridge components. Corrosion or cracking of steel within concrete members will be detected and evaluated. The system will be used as a self clamping and moving sensing device that can be installed on a concrete girder. Data from the sensing device is transmitted via a wireless communication system to data recording/analysis equipment on the ground. The sensing device may also be operated manually to allow inspection of local areas such as the end bearing or cable anchorage locations in cable bridges. Through performing a correlation analysis of recorded data, an assessment of the condition of the member under test is made. Reference data base for the correlation analysis is established through laboratory and field testing with known conditions.

Vertical vibration control system for PC cable-stayed bridge during cantilever construction; Shuketa jogedo seishin sochi ni yoru haridashi sekoji no PC shachokyo no seishin

Energy Technology Data Exchange (ETDEWEB)

Oshio, M.; Nakano, R.; Niihara, Y.; Yano, K.; Takeda, T. [Kajima Corp., Tokyo (Japan)

1995-12-20

A PC cable-stayed bridge under extension construction having long span length may have long-cycle vibration generated because of wind. The vibration puts workers working on main girders into a state of seasick causing the workability to drop. Therefore, with an objective to reduce vibration occurring on the main girders during construction, discussions were given on application of an active type vertical vibration absorbing device. The vibration absorbing device is an active system that a weight is driven vertically by a hydraulic actuator. The device was developed with a target that damping ratio when a maximum extension is 120 m becomes three times that when no vibration is absorbed for a 5-span continuous PC cable-stayed bridge with a length of 675 m, a central span of 260 m, and a width of 11 m. A cage housing the weight is connected with the actuator at its top by using pins, and the weight is supported being suspended from the top of the actuator. Vibration is absorbed by utilizing reactive force generated when the weight is driven vertically by the hydraulic actuator. The hydraulic actuator contains a gas spring that supports the dead weight of the weight. Experiments have verified the effectiveness of the vertical vibration absorbing device. 4 refs., 12 figs., 3 tabs.

Stress Analysis for the Critical Metal Structure of Bridge Crane

Science.gov (United States)

Ling, Zhangwei; Wang, Min; Xia, Junfang; Wang, Songhua; Guo, Xiaolian

2018-01-01

Based on the type of connection between the main girder and end beam of electrical single beam crane, the finite element analysis model of a full portal crane was established. The stress distribution of the critical structure under different loading conditions was analyzed. The results shown that the maximum Mises stress and deflection of the main girder were within the allowable range. And the connecting location between end beam web and main girder had higher stress than other region, especially at the lower edge and upper edge of the end beam web and the area near the bolt hole of upper wing panel. Therefore it is important to inspect the connection status, the stress condition and the crack situation nearing connection location during the regular inspection process to ensure the safety of the connection between the main girder and end beam.

Vertical gust response prediction of cable-stayed bridges in yawed wind; Shachokyo no shafu ni yoru enchoku gust oto no yosoku

Energy Technology Data Exchange (ETDEWEB)

Nakamura, S.; Nagamachi, K.; Kawai, Y. [Kawasaki Steel Corp., Tokyo (Japan); Kimura, K.; Fujino, Y. [The University of Tokyo, Tokyo (Japan). Faculty of Engineering; Tanaka, H.

1996-03-01

This paper outlines the vertical gust response analysis method in a yawed wind, gives an analytic example, and compares the experimental result with the analytic result to investigate the application of an analysis method and the validity of assumption and approximation. The vertical gust response to two cable-stayed bridges under construction in a yawed wind was predicted by applying assumption and approximation to the gust response prediction method in a yawed wind with the cantilever model having a plate cross-section manipulated. In this case, the wind velocity component perpendicular to the leading edge was defined as an effective wind velocity, and a bridge axis and the component perpendicular to a bridge axis were separately calculated in response. Moreover, some aerodynamic coefficients of a bridge girder cross-section were approximately obtained from the characteristics of the flat blades with same aspect ratio. The obtained analytic result was compared with the wind tunnel test result based on all bridge models. The result showed that the former almost coincides with the latter, the assumption and approximation of this time are verified in validity, and this analysis method can be used for cable-stayed bridges under construction. 10 refs., 7 figs., 2 tabs.

Estimation of Tsunami Bore Forces on a Coastal Bridge Using an Extreme Learning Machine

Directory of Open Access Journals (Sweden)

Iman Mazinani

2016-04-01

Full Text Available This paper proposes a procedure to estimate tsunami wave forces on coastal bridges through a novel method based on Extreme Learning Machine (ELM and laboratory experiments. This research included three water depths, ten wave heights, and four bridge models with a variety of girders providing a total of 120 cases. The research was designed and adapted to estimate tsunami bore forces including horizontal force, vertical uplift and overturning moment on a coastal bridge. The experiments were carried out on 1:40 scaled concrete bridge models in a wave flume with dimensions of 24 m × 1.5 m × 2 m. Two six-axis load cells and four pressure sensors were installed to the base plate to measure forces. In the numerical procedure, estimation and prediction results of the ELM model were compared with Genetic Programming (GP and Artificial Neural Networks (ANNs models. The experimental results showed an improvement in predictive accuracy, and capability of generalization could be achieved by the ELM approach in comparison with GP and ANN. Moreover, results indicated that the ELM models developed could be used with confidence for further work on formulating novel model predictive strategy for tsunami bore forces on a coastal bridge. The experimental results indicated that the new algorithm could produce good generalization performance in most cases and could learn thousands of times faster than conventional popular learning algorithms. Therefore, it can be conclusively obtained that utilization of ELM is certainly developing as an alternative approach to estimate the tsunami bore forces on a coastal bridge.

Long-Term Vibration Monitoring of the Effects of Temperature and Humidity on PC Girders with and without Fly Ash considering ASR Deterioration

Directory of Open Access Journals (Sweden)

Tuan Minh Ha

2017-01-01

Full Text Available Structural responses have been used as inputs in the evaluation procedures of civil structures for years. Apart from the degradation of a structure itself, changes in the environmental conditions affect its characteristics. For adequate maintenance, it is necessary to quantify the environment-induced changes and discriminate them from the effects due to damage. This study investigates the variation in the vibration responses of prestressed concrete (PC girders, which were deteriorated because of the alkali–silica reaction (ASR, concerning ambient temperature and humidity. Three PC girders were exposed to outdoor weather conditions outside the laboratory, one of which had a selected amount of fly ash in its mixture to mitigate the ASR. The girders were periodically vibration tested for one and a half years. It was found that when the temperature and humidity increased, the frequencies and damping ratios decreased in proportion. No apparent variation in the mode shapes could be identified. A finite element model was proposed for numerical verification, the results of which were in good agreement with the measured changes in the natural frequencies. Moreover, the different dynamic performances of the three specimens indicated that the fly ash significantly affected the vibrations of the PC girders under ASR deterioration.

Stress Regression Analysis of Asphalt Concrete Deck Pavement Based on Orthogonal Experimental Design and Interlayer Contact

Science.gov (United States)

Wang, Xuntao; Feng, Jianhu; Wang, Hu; Hong, Shidi; Zheng, Supei

2018-03-01

A three-dimensional finite element box girder bridge and its asphalt concrete deck pavement were established by ANSYS software, and the interlayer bonding condition of asphalt concrete deck pavement was assumed to be contact bonding condition. Orthogonal experimental design is used to arrange the testing plans of material parameters, and an evaluation of the effect of different material parameters in the mechanical response of asphalt concrete surface layer was conducted by multiple linear regression model and using the results from the finite element analysis. Results indicated that stress regression equations can well predict the stress of the asphalt concrete surface layer, and elastic modulus of waterproof layer has a significant influence on stress values of asphalt concrete surface layer.

Simplified Analytical Method for Optimized Initial Shape Analysis of Self-Anchored Suspension Bridges and Its Verification

Directory of Open Access Journals (Sweden)

Myung-Rag Jung

2015-01-01

Full Text Available A simplified analytical method providing accurate unstrained lengths of all structural elements is proposed to find the optimized initial state of self-anchored suspension bridges under dead loads. For this, equilibrium equations of the main girder and the main cable system are derived and solved by evaluating the self-weights of cable members using unstrained cable lengths and iteratively updating both the horizontal tension component and the vertical profile of the main cable. Furthermore, to demonstrate the validity of the simplified analytical method, the unstrained element length method (ULM is applied to suspension bridge models based on the unstressed lengths of both cable and frame members calculated from the analytical method. Through numerical examples, it is demonstrated that the proposed analytical method can indeed provide an optimized initial solution by showing that both the simplified method and the nonlinear FE procedure lead to practically identical initial configurations with only localized small bending moment distributions.

Large-diameter boring of rock bed by a reveres circulation drill; Ribasu sakyureshon doriru ni yoru daikokei ganban sakko

Energy Technology Data Exchange (ETDEWEB)

Sakae, S.; Torii, K. [Kajima Corp., Tokyo (Japan); Hoshino, S.; Motoyama, M.

1995-09-25

The Itojima Large Bridge is a road bridge of 675 m in the total length connecting together the Nagashima Island and the Itojima Island in the northwest district of Kagoshima Prefecture, having a central span of 260 m and comprising a 5-span-continuous PC cable stayed bridges and PC box girder bridges. The foundation of this bridge employs a multi-pillar type pile structure. The piling work was started in July, 1991 by a hole inset method in a severe working environment where the depth of water is 20 m, the range of the tides is 4 m, the speed of tidal current is 2 kt, the rock bed structure is complicated and the steep seabed is steeply inclined. This report describes the results of the execution of the reverse circulation drilling, which has a high general versatility in rock bed boring, using self-lifting barges and large working boats during the rock bed boring for the foundation piling for the construction of the Itojima Large Bridge. The report, especially, also introduces the details of the work that casing pipes were driven into a stable rock bed by a vibrojet method for the measure against the collapse of a bore wall which occurred during the boring work. 24 figs., 14 tabs.

Discussion on the installation checking method of precast composite floor slab with lattice girders

Science.gov (United States)

Chen, Li; Jin, Xing; Wang, Yahui; Zhou, Hele; Gu, Jianing

2018-03-01

Based on the installation checking requirements of China’s current standards and the international norms for prefabricated structural precast components, it proposed an installation checking method for precast composite floor slab with lattice girders. By taking an equivalent composite beam consisted of a single lattice girder and the precast concrete slab as the checking object, compression instability stress of upper chords and yield stress of slab distribution reinforcement at the maximum positive moment, tensile yield stress of upper chords, slab normal section normal compression stress and shear instability stress of diagonal bars at the maximum negative moment were checked. And the bending stress and deflection of support beams, strength and compression stability bearing capacity of the vertical support, shear bearing capacity of the bolt and compression bearing capacity of steel tube wall at the bolt were checked at the same time. Every different checking object was given a specific load value and load combination. Application of installation checking method was given and testified by example.

Wind tunnel test on PC cable-stayed bridge; PC shachokyo no taifu seino shiken

Energy Technology Data Exchange (ETDEWEB)

Kubo, Y. [Kyushu Inst. of Technology, Kitakyushu (Japan). Faculty of Engineering

1997-05-30

This paper describes the wind tunnel test on a PC cable-stayed bridge. The aerodynamic force that acts on a building is represented by the drag that works in the wind direction, the lift that works perpendicularly to the wind direction, and the aerodynamic moment that causes rotation. In the measurement of wind load, a girder is partially extracted in the wind tunnel and set in a three-component balance, and the drag, lift, and aerodynamic moment are measured using a strain meter while blowing the wind. In a wind tunnel experiment, the similarity on Reynolds number, field number, rigidity, hydraulic force, structural attenuation, and reduced wind velocity is required. However, the wind velocity in the actual bridge uses the same air as that in an experiment. The similarity rule on the Reynolds is not thus satisfied. It is necessary to cause no self-excited vibration (galloping and flutter) as wind-resistant performance and suppress the eddy excitation to less than the allowable amplitude. Moreover, the three-dimensional experiment using an elastic model is conducted in addition to the two-dimensional experiment using a rigid model. In the three-dimensional experiment, various vibration modes that occur in the actual bridge appear. 12 refs., 15 figs.

Estimation of hull girder vertical bending moments including non-linear and flexibility effects using closed form expressions

DEFF Research Database (Denmark)

Pedersen, Preben Terndrup; Jensen, Jørgen Juncher

2009-01-01

A simple but rational procedure for prediction of extreme wave-induced hull girder bending moment is presented. The procedure takes into account main ship hull characteristics such as: length, breadth, draught, block coefficient, bow flare coefficient, forward speed and hull flexibility. The wave......-linear strip theory calculations and supplemented with new closed form results for the hogging bending moment. Focus is on the extreme hull girder hogging bending moment. Due to the few input parameters this procedure can be used to estimate the wave-induced bending moments at the conceptual design phase....... Another application area is for novel single hull ship types not presently covered by the rules of the classification societies. As one application example the container ship M/S Napoli is considered....

Puente Reich, Viena - Austria

Directory of Open Access Journals (Sweden)

Staber, Johann

1979-11-01

Full Text Available The Reich Bridge substitutes for another bridge linking the centre and North areas of the city, collapsed on 8th August 1976. The purpose of this bridge is to regulate traffic and lends urban distinction to this city section. The structure is a suspended bridge, some 300 m in span, with two abutments on the banks and two piers for anchoring support. The cross section is a box girder large enough to carry motor traffic and the urban railway line.

El puente Reich sustituye a otro anterior, derrumbado el 8 de agosto de 1976, que servía de enlace entre el centro y la parte norte de la ciudad de Viena. Debe servir para ordenar el tráfico y para realzar urbanísticamente esta zona de la ciudad. La estructura que presenta es un puente colgante de unos 300 m de luz, con dos estribos en zona de tierra y dos apoyos para los anclajes El perfil es una viga-cajón Vierendel que permite el tráfico automovilístico y el trazado del Metropolitano.

Influence of apparent wave velocity on seismic performance of a super-long-span triple-tower suspension bridge

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Hao Wang

2015-06-01

Full Text Available As one of the main characteristics of seismic waves, apparent wave velocity has great influence on seismic responses of long-span suspension bridges. Understanding these influences is important for seismic design. In this article, the critical issues concerning the traveling wave effect analysis are first reviewed. Taizhou Bridge, the longest triple-tower suspension bridge in the world, is then taken as an example for this investigation. A three-dimensional finite element model of the bridge is established in ABAQUS, and the LANCZOS eigenvalue solver is employed to calculate the structural dynamic characteristics. Traveling wave effect on seismic responses of these long-span triple-tower suspension bridges is investigated. Envelopes of seismic shear force and moment in the longitudinal direction along the three towers, relative displacements between the towers and the girder, and reaction forces at the bottoms of the three towers under different apparent wave velocities are calculated and presented in detail. The results show that the effect of apparent wave velocity on the seismic responses of triple-tower suspension bridge fluctuates when the velocity is lower than 2000 m/s, and the effects turn stable when the velocity becomes larger. In addition, the effects of traveling wave are closely related to spectral characteristics and propagation direction of the seismic wave, and seismic responses of components closer to the source are relatively larger. Therefore, reliable estimation of the seismic input and apparent wave velocity according to the characteristics of the bridge site are significant for accurate prediction of seismic responses. This study provides critical reference for seismic analysis and design of long-span triple-tower suspension bridges.

Experimental assessment of an RFID-based crack sensor for steel structures

Science.gov (United States)

E Martínez-Castro, R.; Jang, S.; Nicholas, J.; Bansal, R.

2017-08-01

The use of welded steel cover plates had been a common design practice to increase beam section capacity in regions of high moment for decades. Many steel girder bridges with cover plates are still in service. Steel girder bridges are subject to cyclic loading, which can initiate crack formation at the toe of the weld and reduce beam capacity. Thus, timely detection of fatigue cracks is of utmost importance in steel girder bridge monitoring. To date, crack monitoring methods using in-house radio frequency identification (RFID)-based sensors have been developed to complement visual inspection and provide quantitative information of damage level. Offering similar properties at a reduced cost, commercial ultra-high frequency (UHF) passive RFID tags have been identified as a more financially viable option for pervasive crack monitoring using a dense array of sensors. This paper presents a study on damage sensitivity of low-cost commercial UHF RFID tags for crack detection and monitoring on metallic structures. Using backscatter power as a parameter for damage identification, a crack sensing system has been developed for single and multiple tag configurations for increased sensing pervasiveness. The effect on backscatter power of the existence and stage of crack propagation has been successfully characterized. For further automation of crack detection, a damage index based on the variation of backscatter power has also been established. The tested commercial RFID-based crack sensor contributes to the usage of this technology on steel girder bridges.

Environmental Durability of Reinforced Concrete Deck Girders Strengthened for Shear with Surface-Bonded Carbon Fiber-Reinforced Polymer

Science.gov (United States)

2009-05-01

"This research investigated the durability of carbon fiber-reinforced polymer composites (CFRP) used for shear strengthening reinforced concrete deck girders. Large beams were used to avoid accounting for size effects in the data analysis. The effort...

Design and evaluation of steel bridges with double composite action

Science.gov (United States)

2010-02-01

This report presents findings from a cooperative USF/URS/FDOT research study undertaken to develop design rules for : double composite steel bridges. In the study, a 48 ft long, 16 ft wide, 4 ft. 10 in. deep trapezoidal HPS 70W box section : desig...

Failure Load Test of a CFRP Strengthened Railway Bridge in Oumlrnskoumlldsvik, Sweden

DEFF Research Database (Denmark)

Täljsten, Björn; Bergström, Markus; Carolin, Anders

2009-01-01

using carbon fiber reinforced polymer (CFRP) rectangular rods epoxy bonded in sawed up slots, e.g., near surface mounted reinforcement. The strengthening was very successful and resulted in a desired shear failure when the bridge was loaded to failure. The load-carrying capacity in bending...... steel reinforcement by approximately 10%, and increased the height of the compressed zone by 100 mm. When the shear failure occurred, the utilization of the compression concrete and CFRP rods were 100 and 87.5%, respectively. This indicates that a bending failure indeed was about to occur, even though......, Sweden is presented. In this particular test the shear capacity of the concrete girders was of primary interest. However, for any reasonable placement of the load (a line load placed transverse to the track direction) a bending failure would occur. This problem was solved by strengthening for flexure...

Prosthetic rehabilitation using adhesive bridge and fixed-fixed bridge on the maxilla and telescopic crown overdenture on mandible

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Indah Sulistiawaty

2016-12-01

Full Text Available Prosthetic rehabilitation is the rehabilitation process of masticatory and esthetics function for patients missing teeth and alveolar bone by means of manufacture and installation of dentures. The prosthetic rehabilitation commonly used include denture adhesive bridge, fixed-fixed bridge, as well as telescopic overdenture. Adhesive bridge is bridge denture consisting of single pontic and two retainer wings attached to the abutment using cement or resin. Fixed-fixed bridge is a bridge denture with rigid connectors on both ends of the pontics, whereas the telescopic crown Overdenture is a removable denture that uses linked precision on the original tooth in the form of primary coping on abutment and secondary coping on the denture. To expose the procedures of prosthetic rehabilitation using adhesive bridge and fixed-fixed bridge on the maxilla and telescopic crown Overdenture on mandible. Male patients aged 32 years came with complaints of difficulty to chew food because he had lost some teeth behind. In the maxilla, teeth are lost in the region of 15 and 16 performed by making the fixed-fixed bridge with abutment teeth 14 and 17. Loss of teeth in the region of 26, performed the manufacture of adhesive bridge with a box preparation on the occlusal 25 and 27. In the mandible, tooth loss in the region of 36,37,46, and 47 performed manufacture of telescopic crown Overdenture with primer coping on the teeth 35.38, 45, and 48 and the secondary coping on a metal frame. Prosthetic rehabilitation especially in the case of loss of back teeth is very important because with the denture patients can chew properly and maintain the stomatognathic system.

Structural Impact of Construction Loads

Science.gov (United States)

2012-08-01

Numerous bridge construction accidents have occurred across the country because of construction loadings, which are an underemphasized : topic in many DOT specifications and design manuals. Bridge girders are least stable when they are subjected to c...

Maintained ship hull girder ultimate strength reliability considering corrosion and fatigue

DEFF Research Database (Denmark)

Hu, Yong; Cui, W.; Pedersen, Preben Terndrup

2004-01-01

The prupose of this paper is to propose a methodology to assess the time-variant ultimate strength of ship hull girder under the degradations of corrosion and fatigue. The effects of fatigue cracks on the tensile and compressive residual ultimate strength of stiffened panels and unstiffened plates......, webs and flanges, respectively. The effects of inspections and repair are taken into account. A minimum net thickness rule is used to determine repair policies. A procedure is proposed to determine the maximum allowable corrosion thickness of different parts of the hull cross section. The procedure...

A Study of the Bolt Connection System for a Concrete Barrier of a Modular Bridge

Directory of Open Access Journals (Sweden)

Doo-Yong Cho

2018-04-01

Full Text Available Modular technology has been recently studied to reduce the construction periods in the field of bridge construction. However, this method is restricted to the pier, girder, and deck, which are the main members of a bridge, and incidental facilities such as concrete barriers have been rarely studied. Thus, in this study, the connection system of a concrete barrier for modular bridges was developed, and a static loading experiment was performed to verify the structural capacity of the proposed system. The variables of the experiment were the vertical and horizontal bolt connections and the construction method. The barrier and plate were fabricated using match casting methods in which nuts were first inserted into the plates rather than anchor bolts using the conservative method. Moreover, a comparison with the conventional in situ barrier was also performed. The experiments were conducted according to the AASHTO LRFD standard. Consequently, the specimen using the vertical bolt connection had a structural capacity that was equal to 85% of that of the conventional specimen and exhibited similar crack patterns compared with the conventional specimen. In the case of the horizontal bolt connection, the separation in the connection area occurred with the application of the initial load and this specimen exhibited a poor performance because of the increase in the separation distance with the application of the maximum load.

Experimental study on buckling and ultimate strength of thin-walled box stub columns; Usuniku hakogata danmen buzai no zakutsu / shukyoku kyodo tokusei ni kansuru jikkenteki kenkyu

Energy Technology Data Exchange (ETDEWEB)

Nakai, H.; Kitada, T. [Osaka City Univ. (Japan); Oryu, T. [Kawasaki Heavy Industries Ltd., Kobe (Japan)

1998-10-21

Thin-walled box stub columns such as beams of cable-stayed bridge, suspension bridge tower, arch rib of arch bridge and steel piers and so forth can also bear torsion at the same time besides compression and bending. These thin-walled box stub columns may achieve ultimate condition before reaching to plastic condition due to the effect of local buckling and so forth. Accordingly, it is the important topic to study the properties regarding ultimate strength of thin-walled box members in order to evaluate correctly the effect on load bearing resistance of local buckling. In this report, validity of load bearing resistance curve and ultimate strength interaction curve proposed by authors was studied using load bearing capacity experiment results. As a result, all ultimate strengths obtained by the experiment were higher than the ultimate strengths estimated by load bearing capacity curve and ultimate strength interaction curve. Further, it was revealed that the specimens subjected to torsion or subjected to bending and torsion and so forth exceeded the plastic strength due to the effect of strain hardening. 12 refs., 14 figs., 4 tabs.

On the Effect of Hull Girder Flexibility on the Vertical Wave Bending Moment for Ultra Large Container Vessels

DEFF Research Database (Denmark)

Andersen, Ingrid Marie Vincent; Jensen, Jørgen Juncher

2012-01-01

Currently, a number of very large container ships are being built and more are on order, and some concerns have been expressed about the importance of the reduced hull girder stiffness to the wave-induced loads. The main concern is related to the fatigue life, but also a possible increase...... in the global hull girder loads as consequence of the increased hull flexibility must be considered. This is especially so as the rules of the classification societies do not explicitly account for the effect of hull flexibility on the global loads. In the present paper an analysis has been carried out...... in the waves. Slamming forces are determined by a standard momentum formulation. The hull flexibility is modelled as a nonprismatic Timoshenko beam. Generally, good agreement with experimental results and more accurate numerical predictions has previously been obtained in a number of studies. The statistical...

Ultimate strength of a large wind turbine blade

Energy Technology Data Exchange (ETDEWEB)

Moelholt Jensen, Find

2008-05-15

The present PhD project contains a study of the structural static strength of wind turbine blades loaded in flap-wise direction. A combination of experimental and numerical work has been used to address the most critical failure mechanisms and to get an understanding of the complex structural behaviour of wind turbine blades. Four failure mechanisms observed during the fullscale tests and the corresponding FE-analysis are presented. Elastic mechanisms associated with failure, such as buckling, localized bending and the Brazier effect, are studied. Six different types of structural reinforcements helping to prevent undesired structural elastic mechanisms are presented. The functionality of two of the suggested structural reinforcements was demonstrated in full-scale tests and the rest trough FE-studies. The blade design under investigation consisted of an aerodynamic airfoil and a load carrying box girder. In total, five full-scale tests have been performed involving one complete blade and two shortened box girders. The second box girder was submitted to three independent tests covering different structural reinforcement alternatives. The advantages and disadvantages of testing a shortened load carrying box girder vs. an entire blade are discussed. Changes in the boundary conditions, loads and additional reinforcements, which were introduced in the box girder tests in order to avoid undesired structural elastic mechanisms, are presented. New and advanced measuring equipment was used in the fullscale tests to detect the critical failure mechanisms and to get an understanding of the complex structural behaviour. Traditionally, displacement sensors and strain gauges in blade tests are arranged based on an assumption of a Bernoulli-Euler beam structural response. In the present study it is shown that when following this procedure important information about distortions of the cross sections is lost. In the tests presented here, one of the aims was to measure distortion

Strain features and condition assessment of orthotropic steel deck cable-supported bridges subjected to vehicle loads by using dense FBG strain sensors

Science.gov (United States)

Wei, Shiyin; Zhang, Zhaohui; Li, Shunlong; Li, Hui

2017-10-01

Strain is a direct indicator of structural safety. Therefore, strain sensors have been used in most structural health monitoring systems for bridges. However, until now, the investigation of strain response has been insufficient. This paper conducts a comprehensive study of the strain features of the U ribs and transverse diaphragm on an orthotropic steel deck and proposes a statistical paradigm for crack detection based on the features of vehicle-induced strain response by using the densely distributed optic fibre Bragg grating (FBG) strain sensors. The local feature of strain under vehicle load is highlighted, which enables the use of measurement data to determine the vehicle loading event and to make a decision regarding the health status of a girder near the strain sensors via technical elimination of the load information. Time-frequency analysis shows that the strain contains three features: the long-term trend item, the short-term trend item, and the instantaneous vehicle-induced item (IVII). The IVII is the wheel-induced strain with a remarkable local feature, and the measured wheel-induced strain is only influenced by the vehicle near the FBG sensor, while other vehicles slightly farther away have no effect on the wheel-induced strain. This causes the local strain series, among the FBG strain sensors in the same transverse locations of different cross-sections, to present similarities in shape to some extent and presents a time delay in successive order along the driving direction. Therefore, the strain series induced by an identical vehicle can be easily tracked and compared by extracting the amplitude and calculating the mutual ratio to eliminate vehicle loading information, leaving the girder information alone. The statistical paradigm for crack detection is finally proposed, and the detection accuracy is then validated by using dense FBG strain sensors on a long-span suspension bridge in China.

Investigation of Time Series Representations and Similarity Measures for Structural Damage Pattern Recognition

Science.gov (United States)

Swartz, R. Andrew

2013-01-01

This paper investigates the time series representation methods and similarity measures for sensor data feature extraction and structural damage pattern recognition. Both model-based time series representation and dimensionality reduction methods are studied to compare the effectiveness of feature extraction for damage pattern recognition. The evaluation of feature extraction methods is performed by examining the separation of feature vectors among different damage patterns and the pattern recognition success rate. In addition, the impact of similarity measures on the pattern recognition success rate and the metrics for damage localization are also investigated. The test data used in this study are from the System Identification to Monitor Civil Engineering Structures (SIMCES) Z24 Bridge damage detection tests, a rigorous instrumentation campaign that recorded the dynamic performance of a concrete box-girder bridge under progressively increasing damage scenarios. A number of progressive damage test case datasets and damage test data with different damage modalities are used. The simulation results show that both time series representation methods and similarity measures have significant impact on the pattern recognition success rate. PMID:24191136

Investigation of Time Series Representations and Similarity Measures for Structural Damage Pattern Recognition

Directory of Open Access Journals (Sweden)

Wenjia Liu

2013-01-01

Full Text Available This paper investigates the time series representation methods and similarity measures for sensor data feature extraction and structural damage pattern recognition. Both model-based time series representation and dimensionality reduction methods are studied to compare the effectiveness of feature extraction for damage pattern recognition. The evaluation of feature extraction methods is performed by examining the separation of feature vectors among different damage patterns and the pattern recognition success rate. In addition, the impact of similarity measures on the pattern recognition success rate and the metrics for damage localization are also investigated. The test data used in this study are from the System Identification to Monitor Civil Engineering Structures (SIMCES Z24 Bridge damage detection tests, a rigorous instrumentation campaign that recorded the dynamic performance of a concrete box-girder bridge under progressively increasing damage scenarios. A number of progressive damage test case datasets and damage test data with different damage modalities are used. The simulation results show that both time series representation methods and similarity measures have significant impact on the pattern recognition success rate.

Soportes apoyados sobre vigas pretensadas (EE. UU.

Directory of Open Access Journals (Sweden)

Editorial, Equipo

1965-12-01

Full Text Available This work has been awarded a prize by the Prestreesed Concrete Institute. It refers to a number of flyovers on the Arroyo Seco, of California. This river has been canalized, to help drainage in case of heavy rainfall. The canal runs through a highly populated zone, and a motor road and accessory ramps had to cross the canal. The resulting design involves three prestressed girders, lightly arched in a parabolic outline, resting on each river shore, running along the line of the bridge, over the canal. It was decided that the bridge piles should not rest on the river bed, in order not to reduce its flow capacity. The girders of a maximum length of 39 ms, are box shaped, and stiffened with thin diaphragms. The cylindrical pile, 1.50 m in diameter, is an integral part of the girder, and applies to it a concentrated load of about 4000 tons. The girders rest on reinforced concrete cubes, which in turn are supported by concrete slabs and piles driven into the soil.Esta obra ha sido premiada por el Prestressed Concrete Institute y se refiere a una serie de pasos superiores sobre el Arroyo Seco, en California, que se ha canalizado para servir de desagüe en el caso de avenidas torrenciales. El canal se halla en una zona de edificación densa y se trata del paso—sobre aquél—de una autopista y rampas de acceso. La solución adoptada consistió en tres vigas pretensadas, ligeramente arqueadas con perfil parabólico, apoyadas en las dos márgenes y situadas en correspondencia con los tres soportes, sobre el propio canal, ya que ninguno de aquéllos debía apoyarse en el lecho de este último al objeto de no disminuir su capacidad de desagüe. Las vigas—de unos 39 m de longitud la mayor—son del tipo cajón, rigidizadas con unos diafragmas de pequeño espesor. El soporte cilíndrico, de 1,50 m de diámetro, se solidariza con la viga y le transmite una notable carga concentrada, del orden de 4.000 toneladas. Los apoyos de estas vigas son simples dados

Experimental investigation on FRP to steel adhesively-bonded joint under tensile loading

NARCIS (Netherlands)

Jiang, X.; Kolstein, M.H.; Bijlaard, F.S.K.

2012-01-01

Due to various advantages of Fibre-Reinforced Polymer (FRP) decks, the FRP to steel composite girder system is being increasingly used in the construction of new bridges as well as the rehabilitation projects of old bridges. This paper focus on the mechanical behaviors and failure modes of the

Numerical investigation of the bearing capacity of transversely prestressed concrete deck slabs

NARCIS (Netherlands)

Amir, S.; Van der Veen, C.; Walraven, J.C.; De Boer, A.

2014-01-01

The research subject of this paper is the bearing capacity of transversely prestressed concrete bridge decks between concrete girders under concentrated loads. Experiments on a 1:2 scale model of this bridge were carried out in the laboratory and a 3D nonlinear finite element model was developed in

Caisson disease during the construction of the Eads and Brooklyn Bridges: A review.

Science.gov (United States)

Butler, W P

2004-01-01

The Eads Bridge (St. Louis) and the Brooklyn Bridge (New York City) were testing grounds for caisson construction. These caissons were enormous compressed air boxes used to build riverine piers and abutments anchoring the bridges. Caisson meant faster and cheaper construction, but there was a hidden cost---caisson disease (decompression sickness). Within caissons, workers labored at pressures as high as 55 psig and caisson disease was common. This discourse is a brief history of the caisson, a brief discussion of the illness as viewed in the mid 1800's, and an abbreviated history of the Eads and Brooklyn Bridges. It also provides a detailed description and evaluation of the observations, countermeasures, and recommendations of Dr. Alphonse Jaminet, the Eads Bridge physician, and Dr. Andrew Smith, the Brooklyn Bridge physician, who published reports of their experience in 1871 and 1873, respectively. These and other primary sources permit a detailed examination of early caisson disease and Jaminet's and Smith's thinking also serve as good examples from which to study and learn.

Bridge joint fabrication and validation for SST-1 PF coil winding pack

International Nuclear Information System (INIS)

Prasad, Upendra; Sharma, A.N.; Patel, D.; Doshi, K.; Varmora, P.; Khristi, Y.; Pradhan, S.

2014-01-01

Highlights: • Prototype of bridge type joints fabricated and validated successfully. • Bridge type joints fabricated and validated on one of the SST-1 PF#3T coil successfully. • Joint resistance was measured with precision nano volt meter and PXI based data acquisition system. • Leak tightness of joint box was better than 3 × 10 −6 Pa m 3 s −1 . • The measured joint resistance of bridge type joint was ∼1.6 nano ohm. - Abstract: A novel concept of bridge joint for Poloidal field (PF) magnet of SST-1 with damaged winding pack has been realized. This joint has been fabricated on 5th and 6th layers of PF#3T coil winding pack (WP) after validation at 10 kA at liquid helium temperature of 4.2 K in current lead test chamber. The joint resistance of bridge joint was measured ∼1.6 nΩ at flat top DC current of 10 kA. This type of joint could be economically useful for revival of a shorted and damaged WP superconducting PF magnets of Tokamaks. In this paper, details of bridge joint design, fabrication and validations are discussed

Virtual Box

DEFF Research Database (Denmark)

Davis, Hilary; Skov, Mikael B.; Stougaard, Malthe

2007-01-01

. This paper reports on the design, implementation and initial evaluation of Virtual Box. Virtual Box attempts to create a physical and engaging context in order to support reciprocal interactions with expressive content. An implemented version of Virtual Box is evaluated in a location-aware environment...

Nuevo puente para el oleoducto de Europa Central

Directory of Open Access Journals (Sweden)

Giuliani, G.

1971-04-01

Full Text Available This bridge runs over the Po river, near Pavia, and is 1,370 m long. It is divided into spans of 36 m length each. The horizontal structure of the bridge consists of sets of four continuous girders, running over six spans, and two continuous girders, extending over seven spans. The piles are 14 m high and 1.50 m in diameter, and rest on the extension of the foundation piles. This article describes details of the project and the system of placing the continuous girders.Este puente, construido sobre el río Po, cerca de Pavía, tiene una longitud total de 1.370 m, dividida en tramos de 36 m de longitud, salvados por cuatro vigas continuas, de 6 vanos, y dos vigas continuas, de 7 vanos. Las pilas, de 14 m de altura y 1,50 m de diámetro, se han construido sobre la prolongación de los pilotes de cimientos. El artículo explica las particularidades de la obra y el procedimiento de lanzamiento adoptado.

Planning and design of the Ikedako bride (temporary name); Ikedakokyo (kasho) no keikaku to sekkei

Energy Technology Data Exchange (ETDEWEB)

Mochizuki, H.; Iizuka, Y.; Yukawa, Y. [Japan Highway Public Corporation, Tokyo (Japan)

1997-09-30

This paper describes the planning and design of the Ikeda-Lake Bridge of the Tokushima Express Way. This bridge is a PC (prestressed concrete) five-span continuous balanced arch bridge with a length 705 m. This bridge transverses prefectural road, Ikeda Dam Lake of Yoshino River, park, JR line, national highway, and town road, and both ends of the bridge are tunnels, resulting in the complicated bridging condition. Various bridging methods were examined from the viewpoint of structural characteristics, workability, profitability, maintenance/management, and aspect. A bridge with PC stiffening girders was adopted. The maximum interval between supports is 200 m. This bridge has the largest scale as a concrete arch bridge in Japan. Basements of bridge piers were constructed by pneumatic caisson method and large-diameter deep basement method. Since basements were located in the dam lake and they were quickly constructed in a short period in a non-flood season, steel caissons were separately fabricated in the dock, towed and placed for excavation. For the construction of upper section, overhang method was adopted using movable working vehicle. For the construction of arch section, the arch was overhung simultaneously in the both sides by composing the truss using stiffened girders, arch ribs, vertical members, and temporary cable stayed members, which was the first in Japan. In 1997, basement construction was completed, and construction of bridge piers and a part of the construction of upper section have been started. 2 refs., 12 figs.

Modeling Main Body of Overcrossing Bridge Based on Vehicle-Borne Laser Scanning Data

Science.gov (United States)

Chen, X.; Chen, M.; Wei, Z.; Zhong, R.

2017-09-01

Vehicle-borne laser scanning (VBLS) is widely used to collect urban data for various mapping and modelling systems. This paper proposes a strategy of feature extraction and 3d model reconstruction for main body of overcrossing bridges based on VBLS point clouds. As the bridges usually have a large span, and the clouds data is often affected by obstacles, we have to use round-trip cloud data to avoid missing part. To begin with, pick out the cloud of the bridge body by an interactive clip-box, and group points by scan-line, then sort the points by scanning angle on each scan line. Since the position under the vehicle have a fixed scan-angle, a virtual path can be obtained. Secondly, extract horizontal line segments perpendicular to the virtual path along adjacent scan-lines, and then cluster line segments into long line-strings, which represent the top and bottom edge. Finally, regularize the line-strings and build 3d surface model of the bridge body. Experimental studies have demonstrated its efficiency and accuracy in case of building bridge model. Modelling the stairs at the both end of the bridge will be the direction of the next step.

Rating precast prestressed concrete bridges for shear

Science.gov (United States)

2008-12-01

Shear capacity of real-world prestressed concrete girders designed in the 1960s and 1970s is a concern because : AASHTO Standard Specifications (AASHTO-STD) employed the quarter-point rule for shear design, which is less : conservative for shea...

Analysis of vibration characteristics of a prestressed concrete cable-stayed bridge using strong motion observation data. Jishin kansoku ni motozuku PC shachokyo no shindo tokusei no kaiseki

Energy Technology Data Exchange (ETDEWEB)

Inatomi, T. (Port and Harbour Research Institute, Kanagawa (Japan)); Takeda, T.; Obi, N.; Yamanobe, S. (Kajima Corp., Tokyo (Japan))

1994-05-31

Records of seismic observation were analyzed for the purpose of proving the validity of antiseismic design for a prestressed concrete (PC) cable-stayed bridge. This bridge is a three span continuous PC cable-stayed bridge of 498 m in bridge length, and is constructed on alluvial soft ground. The seismometer used is a servo type accelerometer. The observed frequency and mode of seismic vibration are in good agreement with those in the analysis and hence the validity of modelling of the structure in designing was confirmed. It was also confirmed that the bending vibration and torsional vibration of the main girder are separated as designed. However, some points such as a large difference in the observed vibration and analysed vibration in the mode accompanying rotation of the base are listed as problems to be solved in antiseismic design. In order to investigate the attenuation constant of the upper structure, a seismic wave response analysis was performed and its results were compared with observed ones. When the attenuation constant is assumed to be 2%, agreement of data between analysis and observation is good, and it is considered that the attenuation constant of the upper structure only without the effects of attenuation of energy escape from the base and crack generation in concrete was about 2% in the observed earthquake (maximum acceleration on the ground: 51 Gal). 8 refs., 9 figs., 2 tabs.

Performance evaluation of corrosion-affected reinforced concrete ...

Indian Academy of Sciences (India)

M B Anoop

Abstract. A methodology for performance evaluation of reinforced concrete bridge girders in corrosive ... concrete (RC) members of infrastructural systems, espe- ... bility will be useful for making engineering decisions for ...... Water-cement ratio.

A review of optimization techniques used in the design of fibre composite structures for civil engineering applications

International Nuclear Information System (INIS)

Awad, Ziad K.; Aravinthan, Thiru; Zhuge, Yan; Gonzalez, Felipe

2012-01-01

Highlights: → We reviewed existing optimization techniques of fibre composite structures. → Proposed an improved methodology for design optimization. → Comparison showed the MRDO is most suitable. -- Abstract: Fibre composite structures have become the most attractive candidate for civil engineering applications. Fibre reinforced plastic polymer (FRP) composite materials have been used in the rehabilitation and replacement of the old degrading traditional structures or build new structures. However, the lack of design standards for civil infrastructure limits their structural applications. The majority of the existing applications have been designed based on the research and guidelines provided by the fibre composite manufacturers or based on the designer's experience. It has been a tendency that the final structure is generally over-designed. This paper provides a review on the available studies related to the design optimization of fibre composite structures used in civil engineering such as; plate, beam, box beam, sandwich panel, bridge girder, and bridge deck. Various optimization methods are presented and compared. In addition, the importance of using the appropriate optimization technique is discussed. An improved methodology, which considering experimental testing, numerical modelling, and design constrains, is proposed in the paper for design optimization of composite structures.

46 CFR 111.81-1 - Outlet boxes and junction boxes; general.

Science.gov (United States)

2010-10-01

... fixture, wiring device, or similar item, including each separately installed connection and junction box... used. (d) As appropriate, each outlet-box or junction-box installation must meet the following...

Bridges for Pedestrians with Random Parameters using the Stochastic Finite Elements Analysis

Science.gov (United States)

Szafran, J.; Kamiński, M.

2017-02-01

The main aim of this paper is to present a Stochastic Finite Element Method analysis with reference to principal design parameters of bridges for pedestrians: eigenfrequency and deflection of bridge span. They are considered with respect to random thickness of plates in boxed-section bridge platform, Young modulus of structural steel and static load resulting from crowd of pedestrians. The influence of the quality of the numerical model in the context of traditional FEM is shown also on the example of a simple steel shield. Steel structures with random parameters are discretized in exactly the same way as for the needs of traditional Finite Element Method. Its probabilistic version is provided thanks to the Response Function Method, where several numerical tests with random parameter values varying around its mean value enable the determination of the structural response and, thanks to the Least Squares Method, its final probabilistic moments.

Bridges for Pedestrians with Random Parameters using the Stochastic Finite Elements Analysis

Directory of Open Access Journals (Sweden)

Szafran J.

2017-02-01

Full Text Available The main aim of this paper is to present a Stochastic Finite Element Method analysis with reference to principal design parameters of bridges for pedestrians: eigenfrequency and deflection of bridge span. They are considered with respect to random thickness of plates in boxed-section bridge platform, Young modulus of structural steel and static load resulting from crowd of pedestrians. The influence of the quality of the numerical model in the context of traditional FEM is shown also on the example of a simple steel shield. Steel structures with random parameters are discretized in exactly the same way as for the needs of traditional Finite Element Method. Its probabilistic version is provided thanks to the Response Function Method, where several numerical tests with random parameter values varying around its mean value enable the determination of the structural response and, thanks to the Least Squares Method, its final probabilistic moments.

Predicting camber, deflection, and prestress losses in prestressed concrete members.

Science.gov (United States)

2011-07-01

Accurate predictions of camber and prestress losses for prestressed concrete bridge girders are essential to minimizing the frequency and cost of construction problems. The time-dependent nature of prestress losses, variable concrete properties, and ...

Appendix G : end region design models.

Science.gov (United States)

2013-03-01

The 2007 AASHTO LRFD Bridge Design Specifications contain prescriptive : requirements for the quantity and placement of confinement reinforcement located in the bottom : flange of pretensioned concrete I-girders. This chapter proposes a rational mode...

MODELING MAIN BODY OF OVERCROSSING BRIDGE BASED ON VEHICLE-BORNE LASER SCANNING DATA

Directory of Open Access Journals (Sweden)

X. Chen

2017-09-01

Full Text Available Vehicle-borne laser scanning (VBLS is widely used to collect urban data for various mapping and modelling systems. This paper proposes a strategy of feature extraction and 3d model reconstruction for main body of overcrossing bridges based on VBLS point clouds. As the bridges usually have a large span, and the clouds data is often affected by obstacles, we have to use round-trip cloud data to avoid missing part. To begin with, pick out the cloud of the bridge body by an interactive clip-box, and group points by scan-line, then sort the points by scanning angle on each scan line. Since the position under the vehicle have a fixed scan-angle, a virtual path can be obtained. Secondly, extract horizontal line segments perpendicular to the virtual path along adjacent scan-lines, and then cluster line segments into long line-strings, which represent the top and bottom edge. Finally, regularize the line-strings and build 3d surface model of the bridge body. Experimental studies have demonstrated its efficiency and accuracy in case of building bridge model. Modelling the stairs at the both end of the bridge will be the direction of the next step.

Channel box

International Nuclear Information System (INIS)

Tanabe, Akira.

1993-01-01

In a channel box of a BWR type reactor, protruding pads are disposed in axial position on the lateral side of a channel box opposing to a control rod and facing the outer side portion of the control rod in a reactor core loaded state. In the initial loading stage of fuel assemblies, channel fasteners and spacer pads are abutted against each other in the upper portion between the channel boxes sandwiching the control rod therebetween. Further, in the lower portion, a gap as a channel for the movement of the control rod is ensured by the support of fuel support metals. If the channel box is bent toward the control rod along with reactor operation, the pads are abutted against each other to always ensure the gap through which the control rod can move easily. Further, when the pads are brought into contact with each other, the bending deformation of the channel box is corrected by urging to each other. Thus, the control rod can always be moved smoothly to attain reactor safety operation. (N.H.)

Determination method of optimum pre-stress in cables of cable-stayed bridges by using fuzzy sets theory; Fuzzy riron wo mochiita shachokyo cable no saiteki prestress chikara ketteiho

Energy Technology Data Exchange (ETDEWEB)

Furuta, H. [Kansai Univ., Osaka (Japan); Kaneyoshi, M.; Tanaka, H. [Hitachi Zosen Corp., Osaka (Japan); Kamei, M.

1996-06-20

Generally in cable-stayed bridges, optimum pre-stress is introduced into cables to achieve reducing weight of the cable cross section by reducing and equalizing the cross sectional force of the main girders. However, the conventional optimum stress determining methods require setting the cross section to be repeated. Therefore, in order to omit iterative calculations and derive rational pre-stress, a fuzzy sets theory was introduced. With this method, if upper and lower limits of design values (targeted design values) are inputted, which are desired by a designer to be realized as cross sectional force such as in main girders and towers and cable tension, an optimum stress can be derived automatically by means of a fuzzy linearity regression analysis. The targeted design values are given by experience and engineering judgment, and resetting the cross section is not required as long as a target value which can be tolerated by a hypothetical cross section is given. Since the theory used is a fuzzy sets theory, the derived pre-stress may not be guaranteed as a truly optimum pre-stress. In order to have the result approach an optimum solution, it is important to set adequate upper and lower limits of the targeted design values referring to examples of constructions in the past and experience. 10 refs., 11 figs., 7 tabs.

Optimum design of large span concrete filled steel tubular arch bridge based on static, stability and modal analysis

Institute of Scientific and Technical Information of China (English)

赵长军; 胡隽; 徐兴

2002-01-01

A three-dimensional finite element model was established for a large span concrete filled steel tubular (CFST) arch bridge which is currently under construction. The arch rib, the spandrel columns, the prestressed concrete box-beam, the cast-in-situ concrete plate of bridge deck, the steel box-beam and the crossbeams connecting the two pieces of arch ribs, were modeled by three-dimensional Timoshenko beam elements (3DTBE). The suspenders were modeled by three-dimensional cable elements (3DCE). Both geometric nonlinearity and prestress effect could be included in each kind of element. At the same time a second finite element model with the same geometric and material properties excepted for the sectional dimension of arch rib was set up. Static dynamic analyses were performed to determine the corresponding characteristics of the structure. The results showed that the arch rib's axial rigidity could be determined by static analysis. The stability and vibration of this system could be separated into in-plane modes, out-of-plane modes and coupled modes. The in-plane stability and dynamic characteristics are determined by the arch rib's vertical stiffness and that of out-of-plane is determined by the crossbeams' stiffness and arch rib's lateral stiffness mainly. The in-plane stiffness is much greater than that of out-of-plane for this kind of bridge . The effect of geometric nonlinearity and prestress effect on bridge behavior is insignificant.

Synthesis and spectral characterization of mono- and binuclear copper(II) complexes derived from 2-benzoylpyridine-N4-methyl-3-thiosemicarbazone: Crystal structure of a novel sulfur bridged copper(II) box-dimer

Science.gov (United States)

Jayakumar, K.; Sithambaresan, M.; Aiswarya, N.; Kurup, M. R. Prathapachandra

2015-03-01

Mononuclear and binuclear copper(II) complexes of 2-benzoylpyridine-N4-methyl thiosemicarbazone (HL) were prepared and characterized by a variety of spectroscopic techniques. Structural evidence for the novel sulfur bridged copper(II) iodo binuclear complex is obtained by single crystal X-ray diffraction analysis. The complex [Cu2L2I2], a non-centrosymmetric box dimer, crystallizes in monoclinic C2/c space group and it was found to have distorted square pyramidal geometry (Addison parameter, τ = 0.238) with the square basal plane occupied by the thiosemicarbazone moiety and iodine atom whereas the sulfur atom from the other coordinated thiosemicarbazone moiety occupies the apical position. This is the first crystallographically studied system having non-centrosymmetrical entities bridged via thiolate S atoms with Cu(II)sbnd I bond. The tridentate thiosemicarbazone coordinates in mono deprotonated thionic tautomeric form in all complexes except in sulfato complex, [Cu(HL)(SO4)]·H2O (1) where it binds to the metal centre in neutral form. The magnetic moment values and the EPR spectral studies reflect the binuclearity of some of the complexes. The spin Hamiltonian and bonding parameters are calculated based on EPR studies. In all the complexes g|| > g⊥ > 2.0023 and the g values in frozen DMF are consistent with the dx2-y2 ground state. The thermal stabilities of some of the complexes were also determined.

Air tight electrical box

Energy Technology Data Exchange (ETDEWEB)

Pringle, C.G.

1990-08-14

An air-impervious electrical box to facilitate air sealing a house comprises an integral, rigid box body having a continuous flange, integral with the body, circumscribing and outwardly extending from the sides of the body. This flange is rearwardly positioned behind the front edges of the sides of the body a predetermined distance so that the electrical box may be secured to framing by nailing through the flange. Drywall is then secured to the frame on top of and adjecent to the flange. Such box eliminates the necessity for solid backing and minimizes passage of air through the box and space between the drywall and the box.

Tsunamis: bridging science, engineering and society.

Science.gov (United States)

Kânoğlu, U; Titov, V; Bernard, E; Synolakis, C

2015-10-28

Tsunamis are high-impact, long-duration disasters that in most cases allow for only minutes of warning before impact. Since the 2004 Boxing Day tsunami, there have been significant advancements in warning methodology, pre-disaster preparedness and basic understanding of related phenomena. Yet, the trail of destruction of the 2011 Japan tsunami, broadcast live to a stunned world audience, underscored the difficulties of implementing advances in applied hazard mitigation. We describe state of the art methodologies, standards for warnings and summarize recent advances in basic understanding, and identify cross-disciplinary challenges. The stage is set to bridge science, engineering and society to help build up coastal resilience and reduce losses. © 2015 The Author(s).

Measurements in a container ship of wave-induced hull girder stresses in excess of design values

DEFF Research Database (Denmark)

Andersen, Ingrid Marie Vincent; Jensen, Jørgen Juncher

2014-01-01

This paper describes full-scale measurements of the wave-induced vertical bending moment amidships a 9400 TEU container carrier and focuses on the effect of the hydro-elastic high-frequency vibration on the extreme hogging wave bending moment. One extreme event, where the vertical wave-induced ho...... is quite significant. Finally, the hydro-elastic behaviour of the hull girder is assessed by simple approximations using the measured statistical properties and closed-form expressions and the agreement with the actual measurements is found to be good. © 2014 Elsevier Ltd....

Synthesis and spectral characterization of mono- and binuclear copper(II) complexes derived from 2-benzoylpyridine-N⁴-methyl-3-thiosemicarbazone: crystal structure of a novel sulfur bridged copper(II) box-dimer.

Science.gov (United States)

Jayakumar, K; Sithambaresan, M; Aiswarya, N; Kurup, M R Prathapachandra

2015-03-15

Mononuclear and binuclear copper(II) complexes of 2-benzoylpyridine-N(4)-methyl thiosemicarbazone (HL) were prepared and characterized by a variety of spectroscopic techniques. Structural evidence for the novel sulfur bridged copper(II) iodo binuclear complex is obtained by single crystal X-ray diffraction analysis. The complex [Cu2L2I2], a non-centrosymmetric box dimer, crystallizes in monoclinic C2/c space group and it was found to have distorted square pyramidal geometry (Addison parameter, τ=0.238) with the square basal plane occupied by the thiosemicarbazone moiety and iodine atom whereas the sulfur atom from the other coordinated thiosemicarbazone moiety occupies the apical position. This is the first crystallographically studied system having non-centrosymmetrical entities bridged via thiolate S atoms with Cu(II)I bond. The tridentate thiosemicarbazone coordinates in mono deprotonated thionic tautomeric form in all complexes except in sulfato complex, [Cu(HL)(SO4)]·H2O (1) where it binds to the metal centre in neutral form. The magnetic moment values and the EPR spectral studies reflect the binuclearity of some of the complexes. The spin Hamiltonian and bonding parameters are calculated based on EPR studies. In all the complexes g||>g⊥>2.0023 and the g values in frozen DMF are consistent with the d(x2-y2) ground state. The thermal stabilities of some of the complexes were also determined. Copyright © 2014 Elsevier B.V. All rights reserved.

Appendix C : SR-72 tests.

Science.gov (United States)

2013-03-01

The Florida highway system includes some of the earliest (circa 1950s) pretensioned : concrete bridges in the United States. Shear capacity of Floridas early pretensioned girders is of : interest because the early designs had thin webs and only li...

Self-compacting concrete for prestressed bridge girders

Science.gov (United States)

Erkmen, Bulent

The purpose of this study was to examine social mobility as a motivation for first-generation college students in reaching attainment at two-year technical colleges. The research question was to what degree has the perception of social mobility influenced first generation college students at technical colleges to complete their career educational goals. Graduates of a two-year technical college were asked a series of open-ended questions regarding their past experiences and perceptions of attending and completing a two-year technical college program; their childhood perceptions of their social status; and experiences with family members regarding their change in social class status. These questions were designed to determine their feelings, viewpoints, reflections, experiences, struggles, and thoughts about attainment (completing their post-secondary education) and the extent to which social mobility influenced their decision to complete their education. The benefits of this research include an understanding of social mobility and educational attainment. Results of this study could be used to better understand the process that first generation college students go through in order to attain their educational goals. The information from this study may be useful for technical college administrations to help design programs and processes for future first-generation college students' success and aid in retention of these students.

Strength of Ship Stiffened Panels under Combined Loading

DEFF Research Database (Denmark)

Weicheng, Cui; Wang, Young-jun; Pedersen, Preben Terndrup

2000-01-01

A ship's hull is a box girder structure composed of stiffened panels and therefore, strength of stiffened panels plays a significant role for the ultimate strength analysis of ship structures. In recent years several authors have proposed simplified methods to calculate the ultimate strength of s...

Puentes de carretera de montaña, Inglaterra

Directory of Open Access Journals (Sweden)

Rendel, Palmer y Tritton, Ingenieros

1965-03-01

Full Text Available The new layout of the road between Hirwaun and Abergavenny, in the Welsh district known as «Heads of the Valleys», has involved the construction of four new bridges, which because of the difficult terrain, were very carefully designed before the best solution could be discovered. Traditional methods would have required the use of much scaffolding and tall supports, owing to the depth of the gorges to be traversed. Hence progressive cantilevering from either side of the span was chosen. In three of the four bridges the final method was the one mentioned above. In the other, a treble portal frame, resting on two intermediate slender supports, hinged at their base, was preferred. The first three bridges are all of very similar construction: in each case an initial mass at the springer was concreted, to which additional sections, each 3 m long, were added, and attached by means of prestressed reinforcement. The fourth bridge was built with double T girders, cantilevered in 3 m sections. The 3 m spaces between the chords of parallel girders were concreted at the site. A set of four of these girders, and the slabs between the chords, constitute a box girders, and the depth of this structure decreases from 4.50 ms over the supports to 1.50 m at the crown. The mixed system of prefabricated units, and slabs, concreted at the site, was made possible because of the prestressing.La reforma del trazado de la carretera entre Hirwaun y Abergavenny, en la zona denominada «Heads of the Valleys», ha motivado la construcción de cuatro nuevos puentes que, por su situación y por lo accidentado del terreno, fueron objeto de particular estudio a fin de lograr una solución óptima. La adopción de métodos tradicionales exigía el empleo de grandes cimbras y soportes por la profundidad de las depresiones salvadas. Por ello se recurrió a los sistemas de construcción en voladizos. La solución definitiva fue, pues, de arco en voladizo, en tres de los cuatro

Comparative life cycle cost assessment of painted and hot-dip galvanized bridges.

Science.gov (United States)

Rossi, B; Marquart, S; Rossi, G

2017-07-15

The study addresses the life cycle cost assessment (LCCA) of steel bridges, focusing on the maintenance activities and the maintenance scenario. Firstly, the unit costs of maintenance activities and their durability (i.e. the time between two activities) are evaluated. Pragmatic data are provided for the environment category C4 and for three activities: Patch Up, Overcoating and Remove & Replace. A comparative LCCA for a typical hypothetic steel girder bridge is carried out, either painted or hot-dip galvanized (HDG), in the environmental class C4. The LCC versus the cumulated life is provided for both options. The initial cost of the steel unpainted option is only 50.3% of the HDG option. It is shown that after 'Overcoating' occurring at 18.5 years, the total Net Present Value (NPV) of the painted option surpasses that of the HDG option. A sensitivity analysis of the NPV to the cost and service life parameters, the escalation and discount rates is then performed. The discount and escalation rates, considerably influences the total LCC, following a non-linear trend. The total LCC decreases with the discount rate increasing and, conversely, increases with the escalation rate increasing. Secondly, the influence of the maintenance scenario on the total LCC is assessed based on a probabilistic approach. A permutation of the three independent maintenance activities assumed to occur six times over the life of the bridge is considered and a probability of occurrence is associated to each unique scenario. The most probable scenarios are then classified according to their NPV or achieved service life. This approach leads to the definition of a cost-effective maintenance scenario i.e. the scenario, within all the considered permutations, that has the minimum LCC in a range of lifespan. Besides, the probabilistic analysis also shows that, whatever the scenario, the return on investment period ranges between 18.5 years and 24.2 years. After that period, the HDG option becomes

Evaluation of continuity detail for precast prestressed girders : research project capsule.

Science.gov (United States)

2008-03-01

The construction of a new bridge : crossing the Mississippi River north of : Baton Rouge is currently underway. The : project, named the John James : Audubon Bridge, is a true landmark. Its : main span will be the longest cablestayed : bridge in Nort...

The Assessment of the Ultimate Hull Girder Strength of RO-RO Ship after Damages

Science.gov (United States)

Zubair Muis Alie, Muhammad; Sitepu, Ganding; Izaak Latumahin, Samuel

2018-03-01

Many accidents of Ro-Ro ships happen in Indonesia such as collision and grounding. When the collision or grounding takes place on the Ro-Ro ship, the ultimate strength of hull structure after damage becomes decrease. Car and passenger decks are critical location since collision and/or grounding occur. In the present study, the assessment of the ultimate hull girder strength is conducted. The cross section of Ro-Ro ship is taken to be analyzed. The collision and grounding damages are assumed to be palced on the side and bottom area, respectively. The damages are created by removing the element from the side shell and bottom part. Finally, the result obtained is compared with one another.

Medical and Safety Reforms in Boxing

Science.gov (United States)

Jordan, Barry D.

1988-01-01

The continued existence of boxing as an accepted sport in civilized society has been long debated. The position of the American Medical Association (AMA) has evolved from promoting increased safety and medical reform to recommending total abolition of both amateur and professional boxing. In response to the AMA opposition to boxing, the boxing community has attempted to increase the safeguards in amateur and professional boxing. The United States of America Amateur Boxing Federation, which is the national regulatory agency for all amateur boxing in the United States, has taken several actions to prevent the occurrence of acute brain injury and is currently conducting epidemiologic studies to assess the long-term neuropsychologic consequences of amateur boxing. In professional boxing, state regulatory agencies such as the New York State Athletic Commission have introduced several medical interventions to prevent and reduce neurologic injury. The lack of a national regulatory agency to govern professional boxing has stimulated the formation of the Association of Boxing Commissions and potential legislation for the federal regulation of professional boxing by a federally chartered organization called the United States Boxing Commission. The AMA's opposition to boxing and the medical and safety reforms implemented by the proponents of boxing are discussed. PMID:3385788

Glove box

International Nuclear Information System (INIS)

Morita, Atsushi

1990-01-01

Wire rope earthquake proof supports having sufficient vibration transmitting and attenuating property are disposed between a fixed floor and the bottom of a glove box in order to improve earthquake proofness of the glove box. The vertical weight of the glove box is supported by support legs slidable on the surface of the fixed floor. The wire rope earthquake-proof supports when undergoing a load, cause stretching and rolling against the external force such as earthquakes, and provide flexible spring support and cause a great damping due to friction with strands. Further, the vertical weight is always supported by the support legs and, when a horizontal weight is applied, the glove box slides on the fixed floor freely with slidable members. In this way, stress concentration generated at joint portions of columns and beams can be moderated greatly and earthquake proofness can be improved. Further, quality control and maintenance for the device is almost unnecessary owing to excellent fatigue-resistant characteristics of the wire rope earthquake proof supports. (N.H.)

Bento Boxes

Science.gov (United States)

Hasio, Cindy

2010-01-01

Bento boxes are common objects in Japanese culture, designed to hold enough lunch for one person. They have individual compartments and sometimes multiple tiers for rice, vegetables, and other side dishes. They are made of materials ranging from wood, cloth, aluminum, or plastic. In general, the greater the number of foods, the better the box is…

Design and construction of the Soegawa viaduct; Soegawa kokakyo no sekkei to seko

Energy Technology Data Exchange (ETDEWEB)

Kobayashi, M.; Sueoka, M. [Japan Highway Public Corporation, Tokyo (Japan); Takahashi, M.; Ito, K. [Kajima Corp., Tokyo (Japan)

1997-09-30

This paper describes the precast segment construction of double-span continuous prestressed concrete (PC) box girder with a length of 93 m in the Soegawa Viaduct in Akita Prefecture. The match cast surface of the newly constructed segment is occasionally deformed into arch due to the temperature gradient generated by the hardening heat. To avoid this phenomenon, the minimum segment length more than one-sixth of the segment width of 11.2 m was determined. Compatible type internal/external cable method was adopted for the configuration of PC steel members in the main direction. In this method, steel members for PC were placed outside of concrete as well as inside of concrete. The yard for fabricating segments was made in the back area of abutment of the bridge. Segments fabricated using steel frames were brought in the yard using a crane and stocked. After the support construction, segments were constructed from No.1 segment in order. Since placing accuracy of the whole segments was affected by the placing of the standard segment, the accuracy was improved by the three-dimensional control using surveying equipment. After the construction of segments and tension of PC, the bridge is to be completed in September, 1997. 3 refs., 21 figs., 4 tabs.

Probabilistic seismic hazard assessment for the effect of vertical ground motions on seismic response of highway bridges

Science.gov (United States)

Yilmaz, Zeynep

Typically, the vertical component of the ground motion is not considered explicitly in seismic design of bridges, but in some cases the vertical component can have a significant effect on the structural response. The key question of when the vertical component should be incorporated in design is answered by the probabilistic seismic hazard assessment study incorporating the probabilistic seismic demand models and ground motion models. Nonlinear simulation models with varying configurations of an existing bridge in California were considered in the analytical study. The simulation models were subjected to the set of selected ground motions in two stages: at first, only horizontal components of the motion were applied; while in the second stage the structures were subjected to both horizontal and vertical components applied simultaneously and the ground motions that produced the largest adverse effects on the bridge system were identified. Moment demand in the mid-span and at the support of the longitudinal girder and the axial force demand in the column are found to be significantly affected by the vertical excitations. These response parameters can be modeled using simple ground motion parameters such as horizontal spectral acceleration and vertical spectral acceleration within 5% to 30% error margin depending on the type of the parameter and the period of the structure. For a complete hazard assessment, both of these ground motion parameters explaining the structural behavior should also be modeled. For the horizontal spectral acceleration, Abrahamson and Silva (2008) model was used within many available standard model. A new NGA vertical ground motion model consistent with the horizontal model was constructed. These models are combined in a vector probabilistic seismic hazard analyses. Series of hazard curves developed and presented for different locations in Bay Area for soil site conditions to provide a roadmap for the prediction of these features for future

47 CFR 80.1007 - Bridge-to-bridge radiotelephone installation.

Science.gov (United States)

2010-10-01

... 47 Telecommunication 5 2010-10-01 2010-10-01 false Bridge-to-bridge radiotelephone installation. 80.1007 Section 80.1007 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND... Bridge-to-Bridge Act § 80.1007 Bridge-to-bridge radiotelephone installation. Use of the bridge-to-bridge...

Changes in position and quality of preferred nest box: effects on nest box use by laying hens

DEFF Research Database (Denmark)

Riber, Anja Brinch; Nielsen, Birte L.

2013-01-01

Using laying hens, we investigated whether position of a nest box, both within the pen and relative to other nest boxes, influenced the preference for a nest box, and how a sudden and marked change to the preferred box influenced the use of nest boxes by the hens. Groups (n=12) of 15 Isa Warren...... hens were housed in pens, each with five identical nest boxes in different positions: Two single (in a corner or not) and a triplet of nest boxes (one of which in a corner). The use of nest boxes was determined by the number of eggs laid daily in each box. Three experiments, each lasting 10 days, were...... carried out. First, the undisturbed use of each of the nest box types was investigated, and a strong preference (Peggs laid there. Second, each of the hen groups was moved to another pen allocated at random, and where...

[Boxing: traumatology and prevention].

Science.gov (United States)

Cabanis, Emmanuel-Alain; Iba-Zizen, Marie-Thérèse; Perez, Georges; Senegas, Xavier; Furgoni, Julien; Pineau, Jean-Claude; Louquet, Jean-Louis; Henrion, Roger

2010-10-01

In 1986, a surgeon who, as an amateur boxer himself was concerned with boxers' health, approached a pioneering Parisian neuroimaging unit. Thus began a study in close cooperation with the French Boxing Federation, spanning 25 years. In a first series of 52 volunteer boxers (13 amateurs and 39 professionals), during which MRI gradually replaced computed tomography, ten risk factors were identified, which notably included boxing style: only one of 40 "stylists" with a good boxing technique had cortical atrophy (4.5 %), compared to 15 % of "sloggers". Changes to the French Boxing Federation rules placed the accent on medical prevention. The second series, of 247 boxers (81 amateurs and 266 professionals), showed a clear improvement, as lesions were suspected in 14 individuals, of which only 4 (1.35 %) were probably due to boxing. The third and fourth series were part of a protocol called "Brain-Boxing-Ageing", which included 76 boxers (11 having suffered KOs) and 120 MRI scans, with reproducible CT and MRI acquisitions (9 sequences with 1.5 T then 3 T, and CT). MRI anomalies secondary to boxing were found in 11 % of amateurs and 38 % of professionals (atrophy, high vascular T2 signal areas, 2 cases of post-KO subdural bleeding). CT revealed sinus damage in 13 % of the amateurs and 19 % of the professionals. The risk of acute and chronic facial and brain damage was underline, along with detailed precautionary measures (organization of bouts, role of the referee and ringside doctor, and application of French Boxing Federation rules).

The effects of the pedestal/floor interface on the dynamic characteristics of the storage ring girder support assemblies

International Nuclear Information System (INIS)

Jendrzejczyk, J.A.; Chen, S.S.; Zhu, S.; Mangra, D.; Smith, R.K.

1993-05-01

To avoid unacceptable vibration of the storage ring quadrupoles, and to ensure that the established vibration criteria are satisfied, the philosophy from inception of the APS has been (1) to locate and design the machine to minimize motion of the storage ring basemat and, (2) following construction, to monitor machine operation and user experiments to ensure that vibration sources are not introduced. This report addresses the design of the storage ring girder support assemblies, and, specifically, the effect of the pedestal/floor interface on the dynamic characteristics (i.e., resonant frequencies, damping, and mode shape)

Analysis of post-tensioned girders structural behaviour using continuous temperature and strain monitoring

Science.gov (United States)

Bednarski, Ł.; Sieńko, R.; Howiacki, T.

2017-10-01

This article presents the possibility of using structural health monitoring system data for the analysis of structure’s operation during its life cycle. Within the specific case study it was proved, that continuous, automatic and long term monitoring of selected physical quantities such as strains and temperatures, can significantly improve the assessment of technical condition by identifying hazardous phenomena. In this work the analysis of structural behaviour of post-tensioned girders within the roofing of sport halls in Cracow, Poland, was performed based on measurement results and verified by numerical model carried out in SOFiSTiK software. Thanks to the possibility of performing calculations in real time and informing the manager of the object about abnormalities it is possible to manage the structure in effective way by, inter alia, planning the renovations or supporting decisions about snow removal.

Microclimate boxes for panel paintings

DEFF Research Database (Denmark)

Wadum, Jørgen

1998-01-01

The use of microclimate boxes to protect vulnerable panel paintings is, therefore, not a new phenomenon of the past two or three decades. Rather, it has been a concern for conservators and curators to protect these objects of art at home and in transit since the end of the nineteenth century....... The increased number of travelling exhibitions in recent years has heightened the need to protect paintings during circulation (Thomson 1961; Mecklenburg 1991). The use and design of microclimate boxes have been evolving since 1892. These boxes may be divided into three broad groups: those using an active...... buffer material to stabilize the internal RH, a more recent box containing no added buffer material, and, in recent times, boxes with an altered gas content. Another concern is the appearance (aesthetics) of the box....

Boxing-related head injuries.

Science.gov (United States)

Jayarao, Mayur; Chin, Lawrence S; Cantu, Robert C

2010-10-01

Fatalities in boxing are most often due to traumatic brain injury that occurs in the ring. In the past 30 years, significant improvements in ringside and medical equipment, safety, and regulations have resulted in a dramatic reduction in the fatality rate. Nonetheless, the rate of boxing-related head injuries, particularly concussions, remains unknown, due in large part to its variability in clinical presentation. Furthermore, the significance of repeat concussions sustained when boxing is just now being understood. In this article, we identify the clinical manifestations, pathophysiology, and management of boxing-related head injuries, and discuss preventive strategies to reduce head injuries sustained by boxers.

78 FR 39436 - Temporary Closure of I-65 (I-70/I-65 South Split Interchange to I-70/I-65 North Split Interchange...

Science.gov (United States)

2013-07-01

..., which consists of replacing the northbound and southbound bridge girders and lowering the pavement..., Dockets Management Facility, Room W12-140, 1200 New Jersey Avenue SE., Washington, DC 20590, or fax... Jones, Office of Freight Management and Operations, Office of Operations, (202) 366-2976, Mr. Bill Winne...

Exergaming boxing versus heavy-bag boxing: are these equipotent for individuals with spinal cord injury?

Science.gov (United States)

Mat Rosly, Maziah; Mat Rosly, Hadi; Hasnan, Nazirah; Davis, Glen M; Husain, Ruby

2017-08-01

Current strategies for increased physical activity and exercise in individuals with spinal cord injury (SCI) face many challenges with regards to maintaining their continuity of participation. Barriers cited often include problems with accessing facilities, mundane, monotonous or boring exercises and expensive equipment that is often not adapted for wheelchair users. To compare the physiological responses and user preferences between conventional heavy-bag boxing against a novel form of video game boxing, known as exergaming boxing. Cross-sectional study. Exercise laboratory setting in a university medical center. Seventeen participants with SCI were recruited, of which sixteen were male and only one female. Their mean age was 35.6±10.2 years. All of them performed a 15-minute physical exercise session of exergaming and heavy-bag boxing in a sitting position. The study assessed physiological responses in terms of oxygen consumption, metabolic equivalent (MET) and energy expenditure between exergaming and heavy-bag boxing derived from open-circuit spirometry. Participants also rated their perceived exertion using Borg's category-ratio ratings of perceived exertion. Both exergaming (MET: 4.3±1.0) and heavy-bag boxing (MET: 4.4±1.0) achieved moderate exercise intensities in these participants with SCI. Paired t-test revealed no significant differences (P>0.05, Cohen's d: 0.02-0.49) in the physiological or perceived exertional responses between the two modalities of boxing. Post session user survey reported all the participants found exergaming boxing more enjoyable. Exergaming boxing, was able to produce equipotent physiological responses as conventional heavy-bag boxing. The intensity of both exercise modalities achieved recommended intensities for health and fitness benefits. Exergaming boxing have the potential to provide an enjoyable, self-competitive environment for moderate-vigorous exercise even at the comfort of their homes.

Invariant box-parameterization of neutrino oscillations

International Nuclear Information System (INIS)

Weiler, Thomas J.; Wagner, DJ

1998-01-01

The model-independent 'box' parameterization of neutrino oscillations is examined. The invariant boxes are the classical amplitudes of the individual oscillating terms. Being observables, the boxes are independent of the choice of parameterization of the mixing matrix. Emphasis is placed on the relations among the box parameters due to mixing-matrix unitarity, and on the reduction of the number of boxes to the minimum basis set. Using the box algebra, we show that CP-violation may be inferred from measurements of neutrino flavor mixing even when the oscillatory factors have averaged. General analyses of neutrino oscillations among n≥3 flavors can readily determine the boxes, which can then be manipulated to yield magnitudes of mixing matrix elements

First-aid boxes - Reminder

CERN Multimedia

GS Department

2010-01-01

With a view to ensuring optimum use of the first-aid boxes on the CERN site, we should like to remind you of various changes introduced in March 2009: The TSO of the buildings concerned is responsible for the first-aid boxes, including checking their contents.   First-aid boxes may be restocked ONLY at the CERN stores (SCEM No. 54.99.80). This is no longer possible at the Infirmary. The associated cost is charged to the Departments.   First-aid boxes should be used only for mild injuries. All other cases should be referred to the Medical Service Infirmary (Bldg. 57 – ground-floor, tel. 73802) between 8.00 a.m. and 5.30 p.m. or to the Fire and Rescue Service (tel. 74444). N.B.: This information does not apply to the red emergency first-aid boxes in the underground areas or to the emergency kits for use in the event of being splashed with hydrofluoric acid.

47 CFR 80.331 - Bridge-to-bridge communication procedure.

Science.gov (United States)

2010-10-01

... 47 Telecommunication 5 2010-10-01 2010-10-01 false Bridge-to-bridge communication procedure. 80..., Alarm, Urgency and Safety Procedures § 80.331 Bridge-to-bridge communication procedure. (a) Vessels subject to the Bridge-to-Bridge Act transmitting on the designated navigational frequency must conduct...

Repackaging SRS Black Box TRU Waste

International Nuclear Information System (INIS)

Swale, D. J.; Stone, K.A.; Milner, T. N.

2006-01-01

Historically, large items of TRU Waste, which were too large to be packaged in drums for disposal have been packaged in various sizes of custom made plywood boxes at the Savannah River Site (SRS), for many years. These boxes were subsequently packaged into large steel ''Black Boxes'' for storage at SRS, pending availability of Characterization and Certification capability, to facilitate disposal of larger items of TRU Waste. There are approximately 107 Black Boxes in inventory at SRS, each measuring some 18' x 12' x 7', and weighing up to 45,000 lbs. These Black Boxes have been stored since the early 1980s. The project to repackage this waste into Standard Large Boxes (SLBs), Standard Waste Boxes (SWB) and Ten Drum Overpacks (TDOP), for subsequent characterization and WIPP disposal, commenced in FY04. To date, 10 Black Boxes have been repackaged, resulting in 40 SLB-2's, and 37 B25 overpack boxes, these B25's will be overpacked in SLB-2's prior to shipping to WIPP. This paper will describe experience to date from this project

Author Details

African Journals Online (AJOL)

Chakri, Asma. Vol 35 (2017) - Articles Optimization of the box-girder of overhead crane with constrained new bat algorithm. Abstract PDF. ISSN: 2352-9717. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's Partners · Terms and Conditions ...

Invariant box parameterization of neutrino oscillations

International Nuclear Information System (INIS)

Weiler, T.J.; Wagner, D.

1998-01-01

The model-independent 'box' parameterization of neutrino oscillations is examined. The invariant boxes are the classical amplitudes of the individual oscillating terms. Being observables, the boxes are independent of the choice of parameterization of the mixing matrix. Emphasis is placed on the relations among the box parameters due to mixing matrix unitarity, and on the reduction of the number of boxes to the minimum basis set. Using the box algebra, we show that CP-violation may be inferred from measurements of neutrino flavor mixing even when the oscillatory factors have averaged. General analyses of neutrino oscillations among n≥3 flavors can readily determine the boxes, which can then be manipulated to yield magnitudes of mixing matrix elements. copyright 1998 American Institute of Physics

Box-particle intensity filter

OpenAIRE

Schikora, Marek; Gning, Amadou; Mihaylova, Lyudmila; Cremers, Daniel; Koch, Wofgang; Streit, Roy

2012-01-01

This paper develops a novel approach for multi-target tracking, called box-particle intensity filter (box-iFilter). The approach is able to cope with unknown clutter, false alarms and estimates the unknown number of targets. Furthermore, it is capable of dealing with three sources of uncertainty: stochastic, set-theoretic and data association uncertainty. The box-iFilter reduces the number of particles significantly, which improves the runtime considerably. The low particle number enables thi...

Molecular cloning and characterization of an F-box family gene CarF-box1 from chickpea (Cicer arietinum L.).

Science.gov (United States)

Jia, Yuying; Gu, Hanyan; Wang, Xiansheng; Chen, Quanjia; Shi, Shubing; Zhang, Jusong; Ma, Lin; Zhang, Hua; Ma, Hao

2012-03-01

F-box protein family has been found to play important roles in plant development and abiotic stress responses via the ubiquitin pathway. In this study, an F-box gene CarF-box1 (for Cicer arietinum F-box gene 1, Genbank accession no. GU247510) was isolated based on a cDNA library constructed with chickpea seedling leaves treated by polyethylene glycol. CarF-box1 encoded a putative protein with 345 amino acids and contained no intron within genomic DNA sequence. CarF-box1 is a KFB-type F-box protein, having a conserved F-box domain in the N-terminus and a Kelch repeat domain in the C-terminus. CarF-box1 was localized in the nucleus. CarF-box1 exhibited organ-specific expression and showed different expression patterns during seed development and germination processes, especially strongly expressed in the blooming flowers. In the leaves, CarF-box1 could be significantly induced by drought stress and slightly induced by IAA treatment, while in the roots, CarF-box1 could be strongly induced by drought, salinity and methyl jasmonate stresses. Our results suggest that CarF-box1 encodes an F-box protein and may be involved in various plant developmental processes and abiotic stress responses.

Research Article Special Issue

African Journals Online (AJOL)

2016-05-15

May 15, 2016 ... bridge deck and girders, but the first highway applications were in France ... Other advantages are such as the ability to span voids that develop ... Recent progresses in software programing made it simple to utilize ... Recognizing the importance of knowledge gained by existing rigid pavement design, the.

A flexible system to capture sample vials in a storage box - the box vial scanner.

Science.gov (United States)

Nowakowski, Steven E; Kressin, Kenneth R; Deick, Steven D

2009-01-01

Tracking sample vials in a research environment is a critical task and doing so efficiently can have a large impact on productivity, especially in high volume laboratories. There are several challenges to automating the capture process, including the variety of containers used to store samples. We developed a fast and robust system to capture the location of sample vials being placed in storage that allows the laboratories the flexibility to use sample containers of varying dimensions. With a single scan, this device captures the box identifier, the vial identifier and the location of each vial within a freezer storage box. The sample vials are tracked through a barcode label affixed to the cap while the boxes are tracked by a barcode label on the side of the box. Scanning units are placed at the point of use and forward data to a sever application for processing the scanned data. Scanning units consist of an industrial barcode reader mounted in a fixture positioning the box for scanning and providing lighting during the scan. The server application transforms the scan data into a list of storage locations holding vial identifiers. The list is then transferred to the laboratory database. The box vial scanner captures the IDs and location information for an entire box of sample vials into the laboratory database in a single scan. The system accommodates a wide variety of vials sizes by inserting risers under the sample box and a variety of storage box layouts are supported via the processing algorithm on the server.

Dimension measuring method for channel box

International Nuclear Information System (INIS)

Jo, Hiroto.

1995-01-01

The device of the present invention concerns detection of a channel box for spent fuel assemblies of a BWR type reactor, which measures a cross sectional shape and dimension of the channel box to check deformation amount such as expansion. That is, a customary fuel exchanger and a dimension measuring device are used. The lower end of the channel box is measured by a distance sensor of the dimension measuring device when it is aligned with a position of the distance sensor. The channel box is lowered at the same time while detecting axial position data of the fuel exchanger. The position of the channel box in an axial direction is detected based on axial position data of the fuel exchanger. The lower end of the channel box can accurately be recognized by the detection of both of them. Subsequent deformation measurement for the channel box at accurate axial positions is enabled. In addition, since the axial position data of the fuel exchanger per se are detected, an axial profile of the channel box can be measured even if a lifting speed of the channel box is varied on every region. (I.S.)

Heart Rate and Liking During "Kinect Boxing" Versus "Wii Boxing": The Potential for Enjoyable Vigorous Physical Activity Videogames.

Science.gov (United States)

Sanders, Gabriel J; Peacock, Corey A; Barkley, Jacob E; Gish, Brian; Brock, Scott; Volpenhein, Josh

2015-08-01

Nintendo(®) (Kyoto, Japan) "Wii™ Sports Boxing" ("Wii Boxing") and Xbox(®) (Microsoft, Redmond, WA) "Kinect(®) Sports Boxing" ("Kinect Boxing") are both boxing simulation videogames that are available for two different active videogame (AVG) systems. Although these AVGs are similar, the style of gameplay required is different (i.e., upper body only versus total body movements) and may alter physical activity intensity and one's preference for playing one game over the other. AVGs that elicit the greatest physiologic challenge and are preferred by users should be identified in an effort to enhance the efficacy of physical activity interventions and programs that include AVGs. The mean heart rate (HRmean) and peak heart rate (HRpeak) for 27 adults (22.7±4.2 years old) were recorded during four 10-minute conditions: seated rest, treadmill walking at 3 miles/hour, "Wii Boxing," and "Kinect Boxing." Upon completion of all four conditions, participants indicated which condition they preferred, and HRmean and HRpeak were calculated as a percentage of age-predicted maximum heart rate to classify physical activity intensity for the three activity conditions (treadmill, "Wii Boxing," and "Kinect Boxing"). "Kinect Boxing" significantly (P<0.001) increased percentage HRmean (64.1±1.6 percent of age-predicted maximum) and percentage HRpeak (76.5±1.9 percent) above all other conditions: Wii HRmean, 53.0±1.2 percent; Wii HRpeak, 61.8±1.5 percent; treadmill HRmean, 52.4±1.2 percent; treadmill HRpeak, 55.2±2.2 percent. Percentage HRpeak for "Kinect Boxing" was great enough to be considered a vigorous-intensity physical activity. There was no difference (P=0.55) in percentage HRmean between "Wii Boxing" and treadmill walking. Participants also preferred "Kinect Boxing" (P<0.001; n=26) to all other conditions ("Wii Boxing," n=1; treadmill n=0). "Kinect Boxing" was the most preferred and the only condition that was physiologically challenging enough to be classified as a

Myocardial Bridge

Science.gov (United States)

... Center > Myocardial Bridge Menu Topics Topics FAQs Myocardial Bridge En español Your heart is made of muscle, ... surface of the heart. What is a myocardial bridge? A myocardial bridge is a band of heart ...

The three-box paradox revisited

International Nuclear Information System (INIS)

Ravon, Tamar; Vaidman, Lev

2007-01-01

The classical three-box paradox of Kirkpatrick (2003 J. Phys. A: Math. Gen. 36 4891) is compared to the original quantum three-box paradox of Aharonov and Vaidman (1991 J. Phys. A: Math. Gen. 24 2315). It is argued that the quantum three-box experiment is a 'quantum paradox' in the sense that it is an example of a classical task which cannot be accomplished using classical means, but can be accomplished using quantum devices. It is shown that Kirkpatrick's card game is analogous to a different game with a particle in three boxes which does not contain paradoxical features

IMPROVED, FAVORABLE FOR ENVIRONMENT POLYURETHANE COLD-BOX-PROCESS (COLD BOX «HUTTENES-ALBERTUS» .

Directory of Open Access Journals (Sweden)

A. Sergini

2005-01-01

Full Text Available The results of the laboratory and industrial investigations, the purpose of which is improvement of the classical Cold-box-process, i.e. the process of the slugs hardening in cold boxes, are presented.

Reconciling White-Box and Black-Box Perspectives on Behavioral Self-adaptation

DEFF Research Database (Denmark)

Bruni, Roberto; Corradini, Andrea; Gadducci, Fabio

2015-01-01

This paper proposes to reconcile two perspectives on behavioral adaptation commonly taken at different stages of the engineering of autonomic computing systems. Requirements engineering activities often take a black-box perspective: A system is considered to be adaptive with respect to an environ......This paper proposes to reconcile two perspectives on behavioral adaptation commonly taken at different stages of the engineering of autonomic computing systems. Requirements engineering activities often take a black-box perspective: A system is considered to be adaptive with respect...... to an environment whenever the system is able to satisfy its goals irrespectively of the environment perturbations. Modeling and programming engineering activities often take a white-box perspective: A system is equipped with suitable adaptation mechanisms and its behavior is classified as adaptive depending...

Decommissioning a small glove box

International Nuclear Information System (INIS)

Bond, R.D.; McSherry, K.

1985-11-01

An account is given of dismantling a fuel fabrication glove box using simple tooling. The fissile content of the box was first measured by several non-destructive techniques. After cleaning, the box was dismantled using hand tools and finally packed for disposal. A record of operator radiation doses, the time taken for each stage of the operation and packing information is given. (author)

Puente pretensado sobre el río Main

Directory of Open Access Journals (Sweden)

Wittfoht, Hans

1965-04-01

Full Text Available This project, which was adjudicated to the firm Polensky & Zöllner, consists of a prestressed concrete bridge of three spans, 85, 140 and 85 m in length. Their shape and slenderness is well adapted to the natural beauty of the surrounding scenery. The axes of the bridge and of the river make an angle of 72° with respect to each other. Also, the bridge, in planform, is a circular arc of 1400 m radius. In the vertical plane, the outline of the bridge is also a circular arc, but of 14000 m radius. Its concavity faces upwards, and the lowest point is near the crown. The concreting of the two box girders, which support the pavement and sidewalks, has been carried out by a combined method of cantilevering and moveable formwork. The formwork was supported by a sliding framework, which could be shifted from place to place, as the overhanging section of the girders increased. This framework enabled a section 7 by 3.5 m in area to be constructed. Work started at a pillar, and developed simultaneously on both sides of it. The prestressing has been the main aspect of the mixed type of construction adopted. The construction by sections, and the large number of longitudinal and transversal cables has required special care in anchoring and aligning the cables. To avoid cracking, a number of helix shaped tubes were placed in the fresh concrete to absorb the hydration heat of the setting concrete. During the process of construction the girders were rigidly joined to the piles, so that the whole bridge structure became a single monolithic unit.El proyecto definitivo, adjudicado por concurso a la empresa Polensky & Zöllner, consiste en una estructura de hormigón pretensado de tres tramos, de 85, 140 y 85 m de luz, respectivamente, y cuya forma y esbeltez se adaptará a la belleza natural del paisaje local. Los ejes del puente y río forman un ángulo de 72°, y el de la calzada es una línea circular de 1.400 m de radio. En el plano vertical, el perfil del

Design report for shielded glove box

International Nuclear Information System (INIS)

Ku, J. H.; Lee, J. C.; Seo, K. S.; Bang, K. S.; Lee, D. W.; Kim, J. H.; Min, D. K.; Park, S. W.

1999-05-01

For the examination of spent fuels and high radioactive specimens using a specially equipped scanning electron microscope, a shielded glove box was designed and constructed at PIE facility of KAERI. This glove box consisted of shielding walls, containment box, lead glasses, manipulators, gloves, ventilation systems, doors, hot-cell specimen cask adapter, etc. It was emphasized that both the easy operation and radiation safety are important factors in the shielded glove box were installed also considered as a important factor to build the basic concept of the assembling. Two sliding doors and one hinge-type door were installed for the easy installation, operation and maintenance of scanning electron microscope. Containment box which confines the radioactive material into the box consisted of reinforced transparent glasses, aluminum frames and stainless steel plate liner. Therefore everything beyond the containment box can be seen through the lead glass which installed at the front shielding wall. All shielding walls and doors were introduced separately into the room and assembled by bolting. (author). 3 refs., 5 tabs., 18 figs

Box-particle probability hypothesis density filtering

OpenAIRE

Schikora, M.; Gning, A.; Mihaylova, L.; Cremers, D.; Koch, W.

2014-01-01

This paper develops a novel approach for multitarget tracking, called box-particle probability hypothesis density filter (box-PHD filter). The approach is able to track multiple targets and estimates the unknown number of targets. Furthermore, it is capable of dealing with three sources of uncertainty: stochastic, set-theoretic, and data association uncertainty. The box-PHD filter reduces the number of particles significantly, which improves the runtime considerably. The small number of box-p...

Demonstration of Corrosion-Resistant Hybrid Composite Bridge Beams for Structural Applications

Science.gov (United States)

2016-09-01

published by ERDC, visit the ERDC online library at http://acwc.sdp.sirsi.net/client/default. DoD Corrosion Prevention and Control Program ERDC/CERL...loading condition was con- trolled by positive flexure of the center girder at midspan. The HL-93 load rating was controlled by the two lanes loaded

Puente Coronado - San Diego (EE. UU.

Directory of Open Access Journals (Sweden)

Editorial, Equipo

1971-12-01

Full Text Available This 3,5 km long bridge, joining the cities of San Diego and Coronado is one of the longest in the world of this type, and one of the three most important straight line bridges in the United States. Its supporting structure consists of reinforced concrete columns resting on footings or piles, according to whether they are under the sea water or on dry land. The superstructure is partly of metal plates and partly of box girders. The surfacing of the deck consists of asphalt epoxy concrete, of 5 cm depth. Special paint was applied to the bridge, including layers of vinyl, iron oxide and blue vinyl on a zinc base.Este puente, de unos 3 km y medio, que une las ciudades de San Diego y Coronado es uno de los de mayor longitud del mundo, de este tipo, y uno de los tres principales ortótropos de los Estados Unidos de América. Su infraestructura está constituida por pilas de hormigón armado apoyadas sobre pilotes o sobre zapatas, según estén en el mar o en tierra firme. La superestructura está formada, en parte, por chapas metálicas y, en parte, por vigas cajón. El acabado del tablero metálico se realizó a base de hormigón asfáltico de epoxi con un espesor de 5 cm. La pintura es especial y se compone de capas de vinilo, de óxido de hierro y de vinilo azul sobre una capa de cinc.

Channel box dimension measuring method

International Nuclear Information System (INIS)

Oshima, Hirotake; Jo, Hiroto.

1994-01-01

The present invention provides a method for measuring the entire length of a channel box of a fuel assembly of a BWR type reactor. Namely, four sensors are used as one set that generate ultrasonic waves from oblique upper portion, oblique lower portion, upper portion and lower portion of the channel box respectively. The distances between the four sensors and each of the portions of the channel box are measured respectively for both of a reference member and a member to be measured. The entire length of the channel box is measured by calculating the measured values and the angles of the obliquely disposed sensors according to a predetermined formula. According to the method of the present invention, the inclination of the channel box to be measured can be corrected. In addition, accuracy of the measurement is improved and the measuring time is saved as well as the measuring device and operation can be simplified. (I.S.)

Shaping 3-D boxes

DEFF Research Database (Denmark)

Stenholt, Rasmus; Madsen, Claus B.

2011-01-01

Enabling users to shape 3-D boxes in immersive virtual environments is a non-trivial problem. In this paper, a new family of techniques for creating rectangular boxes of arbitrary position, orientation, and size is presented and evaluated. These new techniques are based solely on position data...

The Akashi Kaikyo Bridge and the Storebælt Bridge

DEFF Research Database (Denmark)

Gimsing, Niels Jørgen

1999-01-01

With the completion of the Akashi Kaikyo Bridge and the Storebælt East Bridge the development of the suspension bridge technology in the 20th century has manifested itself in two impressive structures. With the present echnology may bridges of similar (and also more modest) dimensions...... will undoubtedly be built far into the next century. For bridges going beyond the spans of existing bridges it is, however, likely that new concepts will be developed....

Aerodynamic stability of long span suspension bridges with low torsional natural frequencies

DEFF Research Database (Denmark)

Andersen, Michael Styrk; Johansson, Jens; Brandt, Anders

2016-01-01

tests where the torsional frequency was lower than the vertical. But too low torsional stiffness caused large static displacements of the girder at medium–high wind speeds and steady state oscillations driven by a combination of torsional divergence and stalling behavior at the critical wind seed...

Bridge Management Systems

DEFF Research Database (Denmark)

Thoft-Christensen, Palle

In this paper bridge management systems are discussed with special emphasis on management systems for reinforced concrete bridges. Management systems for prestressed concrete bridges, steel bridges, or composite bridges can be developed in a similar way....

Opto-Box

CERN Document Server

Bertsche, David; The ATLAS collaboration; Welch, Steven; Smith, Dale Shane; Che, Siinn; Gan, K.K.; Boyd, George Russell Jr

2015-01-01

The opto-box is a custom mini-crate for housing optical modules, which process and transfer optoelectronic data. The system tightly integrates electrical, mechanical, and thermal functionality into a small package of size 35x10x8 cm^3. Special attention was given to ensure proper shielding, grounding, cooling, high reliability, and environmental tolerance. The custom modules, which incorporate Application Specific Integrated Circuits (ASICs), were developed through a cycle of rigorous testing and redesign. In total, fourteen opto-boxes have been installed and loaded with modules on the ATLAS detector. They are currently in operation as part of the LHC run 2 data read-out chain.

Innovations in Los Alamos alpha box design

International Nuclear Information System (INIS)

Ledbetter, J.M.; Dowler, K.E.; Cook, J.H.

1985-01-01

Destructive examinations of irradiated fuel pins containing plutonium fuel must be performed in shielded hot cells with strict provisions for containing the plutonium. Alpha boxes provide containment for the plutonium, toxic fission products, and other hazardous highly radioactive materials. The alpha box contains windows for viewing and a variety of transfer systems specially designed to allow transfers in and out of the alpha box without spread of the hazardous materials that are contained in the box. Alpha boxes have been in use in the Wing 9 hot cells at Los Alamos National Laboratory for more than 20 years. Features of the newly designed alpha boxes are presented

Complementarity in the Einstein-Bohr photon box

NARCIS (Netherlands)

Dieks, D.G.B.J.; Lam, S

2008-01-01

The Bohr-Einstein photon box thought experiment is a forerunner of the EPR experiment: a packet of radiation escapes from a box, and the box-plus-radiation state remains entangled. Hence, a measurement on the box makes a difference for the state of the far-away radiation long after its escape. This

A Brillouin smart FRP material and a strain data post processing software for structural health monitoring through laboratory testing and field application on a highway bridge

Science.gov (United States)

Bastianini, Filippo; Matta, Fabio; Galati, Nestore; Nanni, Antonio

2005-05-01

Strain and temperature sensing obtained through frequency shift evaluation of Brillouin scattered light is a technology that seems extremely promising for Structural Health Monitoring (SHM). Due to the intrinsic distributed sensing capability, Brillouin can measure the deformation of any individual segment of huge lengths of inexpensive single-mode fiber. In addition, Brillouin retains other typical advantages of Fiber Optic Sensors (FOS), such as harsh environment durability and interference rejection. Despite these advantages, the diffusion of Brillouin for SHM is constrained by different factors, such as the high equipment cost, the commercial unavailability of specific SHM oriented fiber products and even some prejudices on the required sensitivity performances. In the present work, a complete SHM pilot application was developed, installed and successfully operated during a diagnostic load test on the High Performance Steel (HPS) bridge A6358 located at the Lake of the Ozarks (Miller County, MO, USA). Four out of five girders were extensively instrumented with a "smart" Glass Fiber Reinforced Polymer (GFRP) tape having embedded fibers for strain sensing and thermal compensation. Data collected during a diagnostic load test were elaborated through a specific post-processing software, and the strain profiles retrieved were compared to traditional strain gauges and theoretical results based on the AASHTO LRFD Bridge Design Specifications for structural assessment purposes. The excellent results obtained confirm the effectiveness of Brillouin SHM systems for the monitoring of real applications.

Dustproof cooling of the electrical box

Directory of Open Access Journals (Sweden)

Nemec Patrik

2018-01-01

Full Text Available In present are electrical boxes cooled by air through the intake hole on the bottom electrical box to the box space with electrotechnical elements and exhaust through the hole at the top to the surrounding by natural convection. This cooling method is effective but operate with the risk of contamination electrotechnical elements by dust sucking from surrounding air. The goal of this work is solution of the dustproof cooling of the electrical box by natural convection. The work deal with design of the device with the heat transfer by the phase change of the working fluid and experimental measuring its thermal performance at the cooling electrotechnical elements loaded by heat 1 200 W in the dustproof electrical box.

Box graphs and resolutions I

Directory of Open Access Journals (Sweden)

Andreas P. Braun

2016-04-01

Full Text Available Box graphs succinctly and comprehensively characterize singular fibers of elliptic fibrations in codimension two and three, as well as flop transitions connecting these, in terms of representation theoretic data. We develop a framework that provides a systematic map between a box graph and a crepant algebraic resolution of the singular elliptic fibration, thus allowing an explicit construction of the fibers from a singular Weierstrass or Tate model. The key tool is what we call a fiber face diagram, which shows the relevant information of a (partial toric triangulation and allows the inclusion of more general algebraic blowups. We shown that each such diagram defines a sequence of weighted algebraic blowups, thus providing a realization of the fiber defined by the box graph in terms of an explicit resolution. We show this correspondence explicitly for the case of SU(5 by providing a map between box graphs and fiber faces, and thereby a sequence of algebraic resolutions of the Tate model, which realizes each of the box graphs.

Plate forming and break down pizza box

Science.gov (United States)

Pantisano, Frank; Devine, Scott M.

1992-01-01

A standard corrugated paper pizza box is provided with slit cuts cut through the top panel of the pizza box in a shape to form four circular serving plates with a beveled raised edge and cross slit cuts through the bottom panel of the pizza box separating the box into four essentially equal portions for easy disposal.

Railroad Bridges

Data.gov (United States)

Department of Homeland Security — Bridges-Rail in the United States According to The National Bridge Inspection Standards published in the Code of Federal Regulations (23 CFR 650.3), a bridge isA...

The Heuristic Interpretation of Box Plots

Science.gov (United States)

Lem, Stephanie; Onghena, Patrick; Verschaffel, Lieven; Van Dooren, Wim

2013-01-01

Box plots are frequently used, but are often misinterpreted by students. Especially the area of the box in box plots is often misinterpreted as representing number or proportion of observations, while it actually represents their density. In a first study, reaction time evidence was used to test whether heuristic reasoning underlies this…

Injury risk in professional boxing.

Science.gov (United States)

Bledsoe, Gregory H; Li, Guohu; Levy, Fred

2005-10-01

Although a popular endeavor, boxing has fallen under increased scrutiny because of its association with traumatic brain injury. However, few studies have investigated the overall epidemiology of boxing injuries from representative samples, and no study has ever documented the incidence of injuries in female boxers. This study is a review of professional boxing data from the state of Nevada from September 2001 through March 2003. Medical and outcome data for all professional boxing matches occurring in Nevada between September 2001 and March 2003 (n = 524 matches) were analyzed on the basis of a pair-matched, case-control design. Cases were boxers who received an injury during the boxing matches. Boxers who were not injured served as control subjects. Both conditional and unconditional logistic regression models were used to assess risk factors for injury. The overall incidence rate of injury was 17.1 per 100 boxer-matches, or 3.4 per 100 boxer-rounds. Facial laceration accounted for 51% of all injuries, followed by hand injury (17%), eye injury (14%), and nose injury (5%). Male boxers were significantly more likely than female boxers to receive injuries (3.6 versus 1.2 per 100 boxer-rounds, P = 0.01). Male boxing matches also ended in knockouts and technical knockouts more often than did female matches (P boxing matches is high, particularly among male boxers. Superficial facial lacerations are the most common injury reported. Male boxers have a higher rate of knockout and technical knockouts than female boxers. Further research is necessary to determine the outcomes of injury, particularly the long-term neurologic outcome differences between sexes.

Comparative Human and Automatic Evaluation of Glass-Box and Black-Box Approaches to Interactive Translation Prediction

Directory of Open Access Journals (Sweden)

Torregrosa Daniel

2017-06-01

Full Text Available Interactive translation prediction (ITP is a modality of computer-aided translation that assists professional translators by offering context-based computer-generated continuation suggestions as they type. While most state-of-the-art ITP systems follow a glass-box approach, meaning that they are tightly coupled to an adapted machine translation system, a black-box approach which does not need access to the inner workings of the bilingual resources used to generate the suggestions has been recently proposed in the literature: this new approach allows new sources of bilingual information to be included almost seamlessly. In this paper, we compare for the first time the glass-box and the black-box approaches by means of an automatic evaluation of translation tasks between related languages such as English–Spanish and unrelated ones such as Arabic–English and English–Chinese, showing that, with our setup, 20%–50% of keystrokes could be saved using either method and that the black-box approach outperformed the glass-box one in five out of six scenarios operating under similar conditions. We also performed a preliminary human evaluation of English to Spanish translation for both approaches. On average, the evaluators saved 10% keystrokes and were 4% faster with the black-box approach, and saved 15% keystrokes and were 12% slower with the glass-box one; but they could have saved 51% and 69% keystrokes respectively if they had used all the compatible suggestions. Users felt the suggestions helped them to translate faster and easier. All the tools used to perform the evaluation are available as free/open–source software.

Implementation of Bridge Management System on Interurban Bridge in Maluku Province

Directory of Open Access Journals (Sweden)

Erwin Marasabessy

2015-05-01

Full Text Available Bridges as transport infrastructures play a vital role in smoothing traffic flows. The success of a bridge in playing its role and serving its function depends on its management. The Directorate General of Highways of the Ministry of Public Work has used a system to manage bridges known as the Bridge Management System (BMS. The system allows a systematic plan and provides a uniform procedure for all bridge operation activities on the national and provincial level. Data from Implementation Agency of National Inter-Urban Roads of Area IX, Northern Maluku in 2011 indicates that the total length of national roads in Maluku Province is 15,238.01 M, with a total of 562 bridges. In Ambon Island, especially, there are 52 bridges totaling 1,176.25 m in length. The study was conducted at several inter-urban bridges in Maluku Province of Ambon Island: Wai Batu Merah, Wai Ruhu, Wai Lawa, Wai Yari and Wai Tua bridges. Assessment of bridge structure conditions was conducted visually to determine the conditions of the existing bridges comprehensively by referring to the Bridge Management System (BMS complemented with a computer-based Bridge Management Information System (BMIS. Condition scores for the five bridges—Wai Batu Merah, Wai Ruhu, Wai Lawa, Wai Yari, and Wai Tua, according to Bridge Management System, are 2, 1, 2, 1, and 2 respectively. The scores of the five bridges indicate that their physical condition can be categorized as good or with minor defects. Based on technical screening, the proposed treatment for Wai Batu Merah, Wai Ruhu, Wai Lawa, dan Wai Tua bridges is the rehabilitation of their sub-elements. As for the Wai Yari Bridge, the treatment will be maintained regularly. The defect repair costs are IDR 149,138,238.00, IDR 81,048,000.00, IDR 174,579,106.10, IDR 79,233,324.01 and IDR 238,323,258.60 for Wai Batu, Wai Ruhu, Wai Lawa, Wai Yari, and Wai Tua Bridges, respectively.

Opto-Box

CERN Document Server

AUTHOR|(INSPIRE)INSPIRE-00377159; The ATLAS collaboration

2016-01-01

The opto-box is a custom mini-crate for housing optical modules, which process and transfer optoelectronic data. Many novel solutions were developed for the custom design and manufacturing. The system tightly integrates electrical, mechanical, and thermal functionality into a small package of size 35x10x8 cm$^{3}$. Special attention was given to ensure proper shielding, grounding, cooling, high reliability, and environmental tolerance. The custom modules, which incorporate Application Specific Integrated Circuits (ASICs), were developed through a cycle of rigorous testing and redesign. In total, fourteen opto-boxes have been installed and loaded with modules on the ATLAS detector. They are currently in operation as part of the LHC run 2 data read-out chain.

Math in the Box

Science.gov (United States)

DeYoung, Mary J.

2009-01-01

This article describes how to make an origami paper box and explores the algebra, geometry, and other mathematics that unfolds. A set of origami steps that transforms the paper into an open box can hold mathematical surprises for both students and teachers. An origami lesson can engage students in an open-ended exploration of the relationship…

ALUMINUM BOX BUNDLING PRESS

Directory of Open Access Journals (Sweden)

Iosif DUMITRESCU

2015-05-01

Full Text Available In municipal solid waste, aluminum is the main nonferrous metal, approximately 80- 85% of the total nonferrous metals. The income per ton gained from aluminum recuperation is 20 times higher than from glass, steel boxes or paper recuperation. The object of this paper is the design of a 300 kN press for aluminum box bundling.

Box-Cox transformation for QTL mapping.

Science.gov (United States)

Yang, Runqing; Yi, Nengjun; Xu, Shizhong

2006-01-01

The maximum likelihood method of QTL mapping assumes that the phenotypic values of a quantitative trait follow a normal distribution. If the assumption is violated, some forms of transformation should be taken to make the assumption approximately true. The Box-Cox transformation is a general transformation method which can be applied to many different types of data. The flexibility of the Box-Cox transformation is due to a variable, called transformation factor, appearing in the Box-Cox formula. We developed a maximum likelihood method that treats the transformation factor as an unknown parameter, which is estimated from the data simultaneously along with the QTL parameters. The method makes an objective choice of data transformation and thus can be applied to QTL analysis for many different types of data. Simulation studies show that (1) Box-Cox transformation can substantially increase the power of QTL detection; (2) Box-Cox transformation can replace some specialized transformation methods that are commonly used in QTL mapping; and (3) applying the Box-Cox transformation to data already normally distributed does not harm the result.

Long-term bridge performance high priority bridge performance issues.

Science.gov (United States)

2014-10-01

Bridge performance is a multifaceted issue involving performance of materials and protective systems, : performance of individual components of the bridge, and performance of the structural system as a whole. The : Long-Term Bridge Performance (LTBP)...

DLESE Teaching Boxes and Beyond: A promising prototype for structuring web services to support concept- and inquiry-based STEM learning and interdisciplinary partnerships.

Science.gov (United States)

Davis, L.; Weatherley, J.; Bhushan, S.; Khan, H.; de La Chica, S.; Deardorff, R.

2004-12-01

An exciting pilot program took place this summer, pioneering the development of Digital Library for Earth System Education (DLESE) Teaching Boxes with the Univ. of CA. Berkeley Museum of Paleontology, SF State Univ., USGS and 7 middle/high school teachers from the San Francisco area. This session will share the DLESE Teaching Box concept, explain the pilot program, and explore the tremendous opportunities for expanding this notion to embrace interdisciplinary approaches to learning about the Earth in the undergraduate science and pre-service teaching arenas. A Teaching Box is a metaphor for an online assembly of interrelated learning concepts, digital resources, and cohesive narration that bridges the gap between discrete resources and understanding. Within a Teaching Box, an instructor or student can pick a topic and see the concepts that build an understanding of that topic, explore online resources that support learning of those concepts, and benefit from the narration (the glue) that weaves concepts, activities, and background information together into a complete teaching/learning story. In this session, we will demonstrate the emerging Teaching Box prototypes and explore how this platform may promote STEM learning by utilizing DLESE tools and services in ways that begin to blur traditional disciplinary boundaries, overcome limitations of discipline-specific vocabularies, and foster collaboration. We will show ways in which new DLESE Web Services could support learning in this highly contextualized environment. We will see glimpses of how learners and educators will be able to modify or create their own Teaching Boxes specific to a unit of study or course, and perhaps share them with the Earth Science Education community. We will see ways to stay abreast of current Earth events, emerging research, and real-time data and incorporate such dynamic information into one learning environment. Services will be described and demonstrated in the context of Teaching

47 CFR 80.163 - Operator requirements of the Bridge-to-Bridge Act.

Science.gov (United States)

2010-10-01

... 47 Telecommunication 5 2010-10-01 2010-10-01 false Operator requirements of the Bridge-to-Bridge... Requirements § 80.163 Operator requirements of the Bridge-to-Bridge Act. Each ship subject to the Bridge-to-Bridge Act must have on board a radio operator who holds a restricted radiotelephone operator permit or...

Bridge health monitoring metrics : updating the bridge deficiency algorithm.

Science.gov (United States)

2009-10-01

As part of its bridge management system, the Alabama Department of Transportation (ALDOT) must decide how best to spend its bridge replacement funds. In making these decisions, ALDOT managers currently use a deficiency algorithm to rank bridges that ...

Standards and interdisciplinary treatment of boxing injuries of the head in professional boxing on the basis of an IBF World Championship Fight.

Science.gov (United States)

Dragu, Adrian; Unglaub, Frank; Radomirovic, Sinisa; Schnürer, Stefan; Wagner, Walter; Horch, Raymund E; Hell, Berthold

2010-12-01

Boxing injuries are well known in hobby boxing as well as in professional boxing. Especially in professional boxing it is of great importance to implement and follow prevention-, diagnosis- and therapy-standards in order to prevent or at least to minimize injuries of the athlete. The utmost aim would be to establish international prevention-, diagnosis- and therapy-standards for boxing injuries in professional boxing. However, this aim is on a short run unrealistic, as there are too many different professional boxing organisations with different regulations. A realistic short term aim would be to develop a national standard in order to unify the management and medical treatment of boxing injuries in professional boxing. We present the management and interdisciplinary treatment of a professional boxer with a bilateral open fracture of the mandible during a middle weight IBF World Championship Fight. On the basis of this case we want to present and discuss the possibilities of an interdisciplinary and successful medical treatment. In order to prevent or minimize boxing injuries of professional boxers, annual MRI-Scans of the head and neck have to be performed as prevention standard. Furthermore, neurocognitive tests must be performed on a regular basis. Boxing injuries in professional boxing need an interdisciplinary, unbiased and complex analysis directly at the boxing ring. The treatment of the injuries should be only performed in medical centres and thus under constant parameters. The needed qualifications must be learned in mandatory national licence courses of boxing physicians, referees and promoters.

The BOXES Methodology Black Box Dynamic Control

CERN Document Server

Russell, David W

2012-01-01

Robust control mechanisms customarily require knowledge of the system’s describing equations which may be of the high order differential type.  In order to produce these equations, mathematical models can often be derived and correlated with measured dynamic behavior.  There are two flaws in this approach one is the level of inexactness introduced by linearizations and the other when no model is apparent.  Several years ago a new genre of control systems came to light that are much less dependent on differential models such as fuzzy logic and genetic algorithms. Both of these soft computing solutions require quite considerable a priori system knowledge to create a control scheme and sometimes complicated training program before they can be implemented in a real world dynamic system. Michie and Chambers’ BOXES methodology created a black box system that was designed to control a mechanically unstable system with very little a priori system knowledge, linearization or approximation.  All the method need...

47 CFR 80.309 - Watch required by the Bridge-to-Bridge Act.

Science.gov (United States)

2010-10-01

... 47 Telecommunication 5 2010-10-01 2010-10-01 false Watch required by the Bridge-to-Bridge Act. 80... Safety Watches § 80.309 Watch required by the Bridge-to-Bridge Act. In addition to the watch requirement contained in § 80.148, all vessels subject to the Bridge-to-Bridge Act must keep a watch on the designated...

Glove boxes

International Nuclear Information System (INIS)

Eisert, G.A.

1979-01-01

An arrangement for effecting access for performing work within a glove box comprises an elongate arm-length impermeable flexible sleeve, a fitting having an aperture therethrough, adapted to be secured in sealing relation in a port, in a wall of the glove box, the fitting including an outwardly extending lip having at least one continuous groove extending around its outer periphery, one end of the sleeve extending through the aperture in fitting and being folded back against the outer periphery of the lip, a resilient fastening ring securing the sleeve in sealing engagement in the groove, clamping means securing the sleeves to the lip and a glove secured in sealing relation via a bushing to the other end of the sleeve. (author)