Sample records for formwork
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DEFF Research Database (Denmark)
Manelius, Anne-Mette
2012-01-01
relation between formwork design and concrete form and surface. The role of the construction of formwork structures thus acquire careful attention to all details. Yet, the aesthetics of formwork structures while performing its duty supporting concrete is left only as traces or more directly as impactos...
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DEFF Research Database (Denmark)
Manelius, Anne-Mette
2012-01-01
På engelsk: Based on the concept of techné and framed in architectural studies of tectonics and an experimental practice of making, this paper investigates the multiple technological roles of textiles in fabric formwork for concrete in four analytical studies of experimental data of the author......’s doctoral dissertation Fabric Formwork for Concrete – Investigations into Formwork Tectonics and Stereogeneity in Architectural Constructions. In the paper only textile roles are discussed but it is suggested that a study of multiple technological roles of key formwork elements will emphasize...... their potential as ‘common denominators’ between architects, engineers and builders. Findings include textile used for the ‘textilization’ of concrete and the ‘concretization’ of textiles as two opposite starting points in fabric-forming. Recent research into thin-shell construction using fabric formwork is shown...
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Lee, Geoffrey
1997-01-01
To optimise formwork costs and minimise the time for its construction, the contractor needs to understand the guiding principles of safe and efficient formwork construction. He must also have some insight into the relative merits of the various methods, and should appreciate the practical details of formwork construction. This is a practical, heavily illustrated and comprehensive manual for the construction industry. It is equally useful as a text for building students and teachers and trainees. Its large format, and extensive use of line drawings make it clear and straightforward to use.
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Improving Formwork Engineering Using the Toyota Way
Directory of Open Access Journals (Sweden)
Jiun-De Kuo
2011-07-01
Full Text Available Construction is a labor-intensive industry with formwork engineering requiring a disproportionate amount of labor and costs. Formwork accounts for approximately one-third of the cost of reinforced concrete construction, partly because traditional formwork processes frequently result in delivery delays and material waste. The purpose of this research is to adapt production concepts pioneered by Toyota (the “Toyota Way” to improve formwork engineering. The Toyota Way of production consists of four tiers of management philosophy, known as the “4Ps” model. This research adopts the 4Ps as steps for formwork improvement. The first step, “establishing long term vision,” emphasizes long term considerations for formwork improvement. Step two, “establishing value streams,” reviews formwork flows and eliminates wastage. The third step, “developing the crew,” forms mold workers as a team. The final step is “developing a culture of continuous improvement” that provides a basis for constant review and provides a basis for continuous progress. The present research used the Toyota Way to improve formwork engineering. The improvements include reductions in resource waste and increases in operational value. In the long run, the proposed model could provide a learning and growth platform for individuals, the business unit, and the company’s extended network of partners. It could also serve to spur innovative thinking in the improvement of formwork engineering.
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Improving Formwork Engineering Using the Toyota Way
Jiun-De Kuo; Wei-Chieh Wang; Chien-Ho Ko
2011-01-01
Construction is a labor-intensive industry with formwork engineering requiring a disproportionate amount of labor and costs. Formwork accounts for approximately one-third of the cost of reinforced concrete construction, partly because traditional formwork processes frequently result in delivery delays and material waste. The purpose of this research is to adapt production concepts pioneered by Toyota (the “Toyota Way”) to improve formwork engineering. The Toyota Way of production consists of ...
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Literature Mapping: Critical Factors in Industrialized BuildingSystem Plastic Formwork Application
Ghazali, Muhammad Azuan Anif; Bahardin, Nur Fadhilah; Zaidi, Mohd Azian; Baharuddin, Mohd Nurfaisal; Yusof, Mohd Reeza
2016-01-01
Industrialised Building System (IBS) in Malaysia has been practiced for decades. The development of its formal practice parallels with the improvement of the built environment in the nation. One of the applications is on formwork. IBS plastic formwork has been promoted by Construction Industry Development Board Malaysia (CIDB) as an alternative to replace the conventional formwork system but the involvement from the public and private sectors in applying the IBS plastic formwork is seen reluc...
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Traditional formwork system sustainability performance: experts’ opinion
Taher Al-ashwal, Mohammed; Abdullah, Redzuan; Zakaria, Rozana
2017-11-01
The traditional formwork system is one of the commonly used systems in concrete construction. It is considered as one of the least observed activities in term of sustainability performance. In this paper, the sustainability performance of the traditional formwork has been assessed by using a multi-criteria assessment tool to facilitate the decision on the sustainability performance measurement. A quantitative five Likert scale survey study using judgemental sampling is employed in this study. A sample of 93 of engineering construction experts, with different fields including contractors, developers, and consultants in the Malaysian context has made the body of the collected primary data. The results show variety in the distribution of the respondents’ working experience. The sustainability performance is considered moderately sustainable by the experts with only given 40.24 % of the overall total score for the three sustainable categories namely environmental, social and economic. Despite the finding that shows that the economic pillar was rated as the most sustainable aspect in comparison to the environmental and social pillars the traditional formwork system sustainability still needs enhancement. Further incorporation of the social and environmental pillars into the concrete construction the sustainability performance of traditional formwork system could be improved.
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Use of formwork systems in high-rise construction
Kurakova, Oksana
2018-03-01
Erection of high quality buildings and structures within a reasonable time frame is the crucial factor for the competitiveness of any construction organization. The main material used in high-rise construction is insitu reinforced concrete. The technology of its use is directly related to the use of formwork systems. Formwork systems and formwork technologies basically determine the speed of construction and labor intensity of concreting operations. Therefore, it is also possible to achieve the goal of reducing the construction time and labor intensity of works performed by improving the technology of formwork systems use. Currently there are unresolved issues in the area of implementation of monolithic technology projects, and problems related to the selection of a formwork technology, high labor intensity of works, poor quality of materials and structures, etc. are the main ones. The article presents organizational and technological measures, by means of which introduction it is possible to shorten the duration of construction. A comparison of operations performed during formwork installation according to the conventional technology and taking into account the implemented organizational and technological measures is presented. The results of a comparative analysis of economic efficiency assessments are also presented on the example of a specific construction project before and after the implementation of the above mentioned measures. The study showed that introduction of the proposed organizational and technological model taking into account optimization of reinforcing and concreting works significantly improves the efficiency of a high-rise construction project. And further improvement of technologies for the use of insitu reinforced concrete is a promising direction in the construction of high-rise buildings.
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Use of formwork systems in high-rise construction
Directory of Open Access Journals (Sweden)
Kurakova Oksana
2018-01-01
Full Text Available Erection of high quality buildings and structures within a reasonable time frame is the crucial factor for the competitiveness of any construction organization. The main material used in high-rise construction is insitu reinforced concrete. The technology of its use is directly related to the use of formwork systems. Formwork systems and formwork technologies basically determine the speed of construction and labor intensity of concreting operations. Therefore, it is also possible to achieve the goal of reducing the construction time and labor intensity of works performed by improving the technology of formwork systems use. Currently there are unresolved issues in the area of implementation of monolithic technology projects, and problems related to the selection of a formwork technology, high labor intensity of works, poor quality of materials and structures, etc. are the main ones. The article presents organizational and technological measures, by means of which introduction it is possible to shorten the duration of construction. A comparison of operations performed during formwork installation according to the conventional technology and taking into account the implemented organizational and technological measures is presented. The results of a comparative analysis of economic efficiency assessments are also presented on the example of a specific construction project before and after the implementation of the above mentioned measures. The study showed that introduction of the proposed organizational and technological model taking into account optimization of reinforcing and concreting works significantly improves the efficiency of a high-rise construction project. And further improvement of technologies for the use of insitu reinforced concrete is a promising direction in the construction of high-rise buildings.
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[Bone graft reconstruction for posterior mandibular segment using the formwork technique].
Pascual, D; Roig, R; Chossegros, C
2014-04-01
Pre-implant bone graft in posterior mandibular segments is difficult because of masticatory and lingual mechanical constraints, because of the limited bone vascularization, and because of the difficulty to cover it with the mucosa. The formwork technique is especially well adapted to this topography. The recipient site is abraded with a drill. Grooves are created to receive and stabilize the grafts. The bone grafts were harvested from the ramus. The thinned cortices are assembled in a formwork and synthesized by mini-plates. The gaps are filled by bone powder collected during bone harvesting. The bone volume reconstructed with the formwork technique allows anchoring implants more than 8mm long. The proximity of the inferior alveolar nerve does not contra indicate this technique. The formwork size and its positioning on the alveolar crest can be adapted to prosthetic requirements by using osteosynthesis plates. The lateral implant walls are supported by the formwork cortices; the implant apex is anchored on the native alveolar crest. The primary stability of implants is high, and the torque is important. The ramus harvesting decreases operative risks. Copyright © 2014 Elsevier Masson SAS. All rights reserved.
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Safety risk assessment for vertical concrete formwork activities in civil engineering construction.
López-Arquillos, Antonio; Rubio-Romero, Juan Carlos; Gibb, Alistair G F; Gambatese, John A
2014-01-01
The construction sector has one of the worst occupational health and safety records in Europe. Of all construction tasks, formwork activities are associated with a high frequency of accidents and injuries. This paper presents an investigation of the activities and related safety risks present in vertical formwork for in-situ concrete construction in the civil engineering sector. Using the methodology of staticized groups, twelve activities and ten safety risks were identified and validated by experts. Every safety risk identified in this manner was quantified for each activity using binary methodology according to the frequency and severity scales developed in prior research. A panel of experts was selected according to the relevant literature on staticized groups. The results obtained show that the activities with the highest risk in vertical formwork tasks are: Plumbing and leveling of forms, cutting of material, handling materials with cranes, and climbing or descending ladders. The most dangerous health and safety risks detected were falls from height, cutting and overexertion. The research findings provide construction practitioners with further evidence of the hazardous activities associated with concrete formwork construction and a starting point for targeting worker health and safety programmes.
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Stay-in-Place Formwork of TRC Designed as Shear Reinforcement for Concrete Beams
Directory of Open Access Journals (Sweden)
S. Verbruggen
2013-01-01
Full Text Available In order to reduce on-site building time, the construction industry shows an increasing interest in stay-in-place formwork with a reinforcement function after concrete hardening, such as CFRP formwork confinement for columns. The current combined systems however do not answer the demand of the building industry for a material system that is both lightweight and fire safe. High performance textile reinforced cement (TRC composites can address this need. They can be particularly interesting for the shear reinforcement of concrete beams. This paper describes a preliminary analysis and feasibility study on structural stay-in-place formwork made of TRC. Comparative bending experiments demonstrate that a fully steel reinforced beam and an equivalent beam with shear reinforcement in TRC formwork show similar yielding behaviour, indicating that the TRC shear reinforcement system actually works. Moreover, the cracking moment of the concrete was more or less doubled, resulting in a much lower deflection in serviceability limit state than calculated. Digital image correlation measurements show that the latter is due to the crack bridging capacity of the external TRC shear reinforcement.
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'Concrete shell formwork' technology applied to the construction of the Paks Nuclear Power Plant
International Nuclear Information System (INIS)
Fejes, A.
1982-01-01
The conventional formworking technology could not meet the unusual requirements needed in constructing the concrete walls of the nuclear power plant building. A new concrete shell formworking developed in the Soviet Union has been adapted to meet the criteria. Prefabricated concrete shells are mounted separately during construction on separated parts of the reinforcing structure. The steps of the construction process are described with the economic evaluation of this new construction technology. (R.P.)
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Lee, Gloria K L; Chan, Chetwyn C H
2003-01-01
This study aimed at investigating the utilization and applicability of the Dictionary of Occupational Titles (DOT) as a methodology to study the job profile (nature and physical demand) of formwork carpentry in the local situation. Thirty male formwork carpenters were recruited by convenient sampling to participate in a two-hour interview, with reference to the DOT Physical Demand Questionnaire (DOTPDQ) and the WestTool Sort Questionnaire. The information obtained was further consolidated by comparing the results from the interview to three construction sites and training guidelines from the formwork carpentry training centers. The triangulation of the data formulated a job profile of formwork carpenters. The results from the DOTPDQ revealed that workers' work demands were standing, walking, pushing, pulling, reaching, climbing, balancing, stooping, crouching, lifting, carrying, handling and near acuity. This produced an agreement of 84.6% with the original DOT. A discrepancy was found in the demands of kneeling, fingering, far acuity and depth perception. The discrepancy between the data from the United States and local appeared to be minimal. It was thus inferred that the DOT-based job profile was largely valid for describing formwork carpentry in Hong Kong. In-depth analysis should be conducted to further substantiate the validity of utilizing the DOT system for other job types and their physical demands.
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Cracked reinforced concrete walls of chimneys, silos and cooling towers as result of using formworks
Directory of Open Access Journals (Sweden)
Maj Marek
2018-01-01
Full Text Available There are presented in this paper some problems connected with reinforced concrete shell objects operation in the aggressive environment and built in method of formworks. Reinforced concrete chimneys, cooling towers, silos and other shells were built for decades. Durability of cracked shells are one of the most important parameters during process of designing, construction and exploitation of shells. Some reasons of appearance of horizontal and vertical cracks as temperature, pressure of stored material, live loads e.g. dynamic character of wind, moisture, influence of construction joints, thermal insulation, chemistry active environmental etc. reduce the carrying capacity of the walls. Formworks, as is occurred recently, are the reason for technological joints with leaking connection, imperfections of flexible formworks slabs and as result can initiate cracks. Cracked surface of this constructions causes decreasing capacity and lower the state of reliability. Horizontal, vertical cracks can caused corrosion of concrete and steel bars, decreasing stiffness of contraction, increasing of deflection and carbonation of concrete cover. Local and global imperfactions of concrete shells are increasing according to greater number of cracks...
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Comparative Analysis of Houses Built from Insulating Concrete Formwork – case Study
Directory of Open Access Journals (Sweden)
Mačková Daniela
2015-11-01
Full Text Available More and more, people are looking to build and live in different ways. They want houses with a high standard of living and reasonable production and maintenance costs. However, they also want to build a way that does not adversely affect their quality of life. Currently, the using of modern methods of construction (MMC expands consistently year on year. MMC include prefabricated products made in the factory and also new methods of building that are site-based and they are regarded as a means of achieving higher quality, reducing time spent onsite, increasing safety and overcoming skills shortages in the industry. Aim of this paper is to analyze and compare, trough case study, technical, cost and technological parameters of house built by modern method of construction (from insulating concrete formwork and by traditional method (from brick system. The subject of case study is house modeled in two variants of insulating concrete formwork and a variant bricks and ceiling system. In conclusion, there is selected optimal method and system for house construction through multicriteria optimization.
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Effect of cementitious permanent formwork on moisture field of internal-cured concrete under drying
Wang, Jiahe; Zhang, Jun; Ding, Xiaoping; Zhang, Jiajia
2018-02-01
Drying shrinkage of concrete may still be the main source of cracking in concrete structures, even though the autogenous shrinkage of concrete can be effectively reduced by using internal curing. In the present paper, the effect of internal curing with pre-soaked lightweight aggregate and engineered cementitious composite permanent formwork (ECC-PF) on a moisture distribution in three kinds of concrete in a drying environment are investigated from both aspects of experiments and theoretical modeling. The test results show that the combination use of ECC-PF and internal curing can well maintain the humidity at a relatively high level not only at a place far from drying surface, but also at a place close to the drying surfaces. The developed model can well catch the characteristics of the moisture distribution in concrete under drying and the impacts of internal curing and ECC-PF can well be reflected as well. The model can be used for the design of concrete structures with combination use of internal curing and permanent formwork.
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DEFF Research Database (Denmark)
Svec, Oldrich; Zirgulis, Giedrius; Bolander, John E.
2014-01-01
The influences of formwork surface on the final orientation of steel fibres immersed in self-compacting concrete and on the resulting mechanical response of the cast structural elements are investigated. Experimental observations of fibre orientation within cast slabs, obtained via computed...... as input to the lattice model. Through comparisons with the experimental data, it is shown that these simulations correctly predict the phenomena of interest. We conclude the paper by highlighting a relationship between the number and orientation of the immersed steel fibres crossing the fracture plane...
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Directory of Open Access Journals (Sweden)
Abdulaziz M Jarkas
2010-08-01
decisiones sobre la eficiencia laboral. Por otro lado, los patrones descritos pueden servir como guía a los administradores de la construcción para una efectiva planificación de actividades y utilización laboral eficiente.Buildability is one of the most important factors affecting labor productivity. Nonetheless, an extensive search of the literature revealed a dearth of research into its effects on in situ reinforced concrete construction, especially at the formwork trade level. Despite the importance of this trade to in situ reinforced concrete material, the influence of buildability factors on formwork labor productivity of major structural elements are yet to be quantified in measurable terms. Grade beams are important structural elements which are primarily used to provide one, or a combination, of the following functions: (1 tie the building foundations to provide the required lateral stiffness at the sub-structural levels; (2 reduce the unsupported free length of columns below grade level; and (3 limit excessive differential settlements of isolated foundations. Therefore, the objective of this research is to investigate and quantify the effects and relative influence of the following buildability factors on formwork labor efficiency of this activity: (a variability of beam sizes; (b beam sizes; and (c number of joints formed at beams intersections. To achieve this objective, a large volume of productivity data was collected and analyzed using the multiple regression method. As a result, the effects and relative influence of the buildability factors investigated are determined. Apart from the variability of beam sizes, the findings show significant effects of these factors on formwork labor productivity, which can be used to provide designers feedback on how well their designs consider the requirements of buildability principles, and the consequences of their decisions on labor efficiency. On the other hand, the depicted patterns may provide guidance to
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DEFF Research Database (Denmark)
Manelius, Anne-Mette
2012-01-01
med metoder for arkitektonisk eksperimenterende praksis (research through design) med inspiration fra eksperimenterende forsknings- og undervisningspraksis indenfor tekstilforskalling i Canada og Skotland. Metoden kobles til en anvendelsesorienteret kontekst i form af erhvervsPhD-projektets forankring...
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The fibre orientation influence in cementitious composite against extreme load resistance
Lovichova, R.; Fornusek, J.; Mara, M.; Kocova, M.; Rihova, Z.
2018-02-01
This paper is focused on resistance of steel fibre-reinforced cement composite against impact of the deformable projectile shot from the 7.62 × 39 caliber. Different values of resistance against impact of the projectile are caused by different orientation of the fibres. The influence of formwork position, which is the main cause of the different orientation of the fibres, is investigated. The resistance was examined on thirty slabs made of ultra-high performance fibre-reinforced concrete (UHPFRC). Fifteen specimens with vertical orientation of formwork and fifteen with horizontal orientation of formwork was made. The resistance is classified according to the visual evaluation and local damage measurement on the front side and the rear side of the examined specimens. The experiment shown positive influence of vertically oriented formwork on the slabs according to their resistance against impact of the projectile.
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DEFF Research Database (Denmark)
Søndergaard, Asbjørn
2014-01-01
In the next decade or so, the widespread adoption of robotics is set to transform the construction industry: building techniques will become increasingly automated both on– and off–site, dispensing with manual labour and enabling greater cost and operational efficiencies. What unique opportunities......, however, does robotics afford beyond operational effectiveness explicitly for the practice of architecture? What is the potential for the serial production of non–standard elements as well as for varied construction processes? In order to scale up and advance the application of robotics, for both...
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Improved monolithic reinforced concrete construction for nuclear power stations
International Nuclear Information System (INIS)
Guenther, P.; Fischer, K.
1983-01-01
Experience has shown that in applying monolithic reinforced concrete in nuclear power plant construction the following auxiliary means are useful: measuring sheets in assembling, welding gauges for reaching high tolerance accuracies of prefabricated reinforced concrete members, suitable lining materials, formwork anchorage and formwork release agents, concrete workability agents, mechanized procedures for finishing and assembling. These means were successfully tested in constructing the Greifswald nuclear power station
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Forming China's new great wall
Energy Technology Data Exchange (ETDEWEB)
Anon
2000-08-01
This one-page article discusses some of the machinery being used for concrete pouring at the Three Gorges hydro project in China, where the total amount of concrete used will total 5.4M m{sup 3} and the monthly pouring rate is 450,000 m{sup 3} . China Gezhouba Construction Group and the Ching Yung Joint Venture are constructing the spillway and dam and the 378 Joint Venture is responsible for the power house. All four main contractors are employing D22 dam formwork. Two purpose built Potain MD 2200 Topbelt tower cranes are used for high volume concrete pouring. The cranes have a lifting capacity of 60 t or 22.8 t at 80 m and can pour concrete over a distance of up to 105 m at a rate of up to 400 m{sup 3} per hour over a radius of 80 m. The working platform, formwork element and dam formwork scaffold are linked in a single unit.
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Energy Technology Data Exchange (ETDEWEB)
Matsuoka, Y.; Shindo, T.; Sakamoto, A. (Taisei Corp., Tokyo (Japan))
1993-08-01
The Kiba Park Grand Bridge is a cable-stayed prestressed concrete (PC) bridge with a length of 186m. The main tower of this PC cable-stayed bridge consists of a pair of vertical columns with height of 60m and a beam connecting the columns. For the purpose of the advanced efficiency of construction without formwork and removal work and the improvement of durability, the precast buried formwork made of polymer impregnated concrete formwork was adopted. Approximate 650 cubic meter of super workable concrete was placed for the upper part ranging from 7th to 17th blocks of vertical columns and the beam. Blast furnace cement B and fly ash were used as binder. Naphthalenesulfonic acid type high performance water reducing agent and lignosulfonic acid type AE (air-entraining) water reducing agent were used as admixtures. Super workable concrete was mixed using forced double-axle mixers in the ready-mixed concrete plant. Satisfactory quality of the fresh concrete and strength of the hardened concrete were obtained. 2 refs., 11 figs., 3 tabs.
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The influence of form release agent application to the quality of concrete surfaces
International Nuclear Information System (INIS)
Klovas, A; Daukšys, M
2013-01-01
The main aim of this article was to obtain concrete surface quality changes by the usage of different form release agent application. Secondly, to determine blemishes of concrete surfaces and divide them according to combined method provided by two documents and by using computer program: CIB Report No. 24 T olerances on blemishes of concrete , GOST 13015.0–83 and I mageJ . Two different concrete compositions were made: BA1 (low fluidity, vibration is needed) and BA8 (high fluidity, vibration is not needed). Three castings with each formwork were conducted. Water emulsion based form release agent was used. Different applications (normal and excessive) of form release agent were used on the formwork
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International Nuclear Information System (INIS)
Lu Weisheng; Yuan Hongping; Li Jingru; Hao, Jane J.L.; Mi Xuming; Ding Zhikun
2011-01-01
The construction and demolition waste generation rates (C and D WGRs) is an important factor in decision-making and management of material waste in any construction site. The present study investigated WGRs by conducting on-site waste sorting and weighing in four ongoing construction projects in Shenzhen city of South China. The results revealed that WGRs ranged from 3.275 to 8.791 kg/m 2 and miscellaneous waste, timber for formwork and falsework, and concrete were the three largest components amongst the generated waste. Based on the WGRs derived from the research, the paper also discussed the main causes of waste in the construction industry and attempted to connect waste generation with specific construction practices. It was recommended that measures mainly including performing waste sorting at source, employing skilful workers, uploading and storing materials properly, promoting waste management capacity, replacing current timber formwork with metal formwork and launching an incentive reward program to encourage waste reduction could be potential solutions to reducing current WGRs in Shenzhen. Although these results were derived from a relatively small sample and so cannot justifiably be generalized, they do however add to the body of knowledge that is currently available for understanding the status of the art of C and D waste management in China.
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International Nuclear Information System (INIS)
Sekimoto, Hisashi; Fuyama, Hiroyuki; Kameda, Ichiro; Fukunaga, Yuuji; Umetada, Isao; Magoshi, Ryutaro
1999-01-01
Mitsubishi Heavy Industries developed a composite steel-concrete beam for constructing elevated horizontal beams for turbine-generator foundations. This system was used at the company's Verification Test Plant at the Takasago Machinery Works. Composite steel-concrete beams are made from U-shaped steel casings that acts as a temporarily formwork and are permanently used as major concrete beam reinforcement. Prefabricated U-shaped steel casings must be placed on top of vertical concrete columns. After steel casings are positioned and secured, concrete is filled. This technique cuts one month from construction time and simplifies required temporary work such as falsework and formwork. This paper details the results of practical research on design and construction as they relate to required strength and vibration. (author)
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Lu, Weisheng; Yuan, Hongping; Li, Jingru; Hao, Jane J L; Mi, Xuming; Ding, Zhikun
2011-04-01
The construction and demolition waste generation rates (C&D WGRs) is an important factor in decision-making and management of material waste in any construction site. The present study investigated WGRs by conducting on-site waste sorting and weighing in four ongoing construction projects in Shenzhen city of South China. The results revealed that WGRs ranged from 3.275 to 8.791 kg/m(2) and miscellaneous waste, timber for formwork and falsework, and concrete were the three largest components amongst the generated waste. Based on the WGRs derived from the research, the paper also discussed the main causes of waste in the construction industry and attempted to connect waste generation with specific construction practices. It was recommended that measures mainly including performing waste sorting at source, employing skilful workers, uploading and storing materials properly, promoting waste management capacity, replacing current timber formwork with metal formwork and launching an incentive reward program to encourage waste reduction could be potential solutions to reducing current WGRs in Shenzhen. Although these results were derived from a relatively small sample and so cannot justifiably be generalized, they do however add to the body of knowledge that is currently available for understanding the status of the art of C&D waste management in China. Copyright © 2010 Elsevier Ltd. All rights reserved.
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Model Simulasi Risiko Rantai Pasok Material Proyek Konstruksi Gedung
Directory of Open Access Journals (Sweden)
Jati Utomo Dwi Hatmoko
2017-07-01
Full Text Available Delays related to materials are one of main problems of construction project. An effective supply chain management has a significant role in preventing this type of delay. The aim of this research is develop risk simulation model of construction supply chain in buildings. The materials include steel bars, steel profiles, formwork, and precast concrete, as they are considered the main building material. The supply chain risks are classified from supply, control, process, and demand sides. Monte Carlo simulation has been performed using Cristal Ball software. Risk identification was done through literature review, site observation, and interviews with 29 contractor personnel working for nine building projects. The simulation results show that the minimum, maximum, and most frequent delays (in days, as follows: steel bars (2.20. 17.05, 11.24; steel profiles (2.12, 15.10, 9.75, formwork (1.79, 16.04, 10.45, precast concrete (1.76, 15.61, 10.24. The sensitivity analysis shows that delay due to change order from client is the most sensitive for steel bars, steel profiles, and formwork of 25.5%, 37.4%, dan 17%, respectively. The results of this research is useful for contractors and owners who can use them as a guidance in identifying, predicting, and mitigating supply chain risks for a successful project.
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Kolakowski, Marcin M.
2010-01-01
Construction of a small earth bag wall in south Sussex: constructing the formwork for entrance, preparing and filling earth bags, ramming layers of earth bags, plastering, artistic sculpturing of the exterior and interior.
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Evaluation of continuity detail for precast prestressed girders.
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...
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Convective Concrete: additive manufacturing to facilitate activation of thermal mass
Directory of Open Access Journals (Sweden)
Dennis de Witte
2017-12-01
Full Text Available Convective Concrete is about a research-driven design process of an innovative thermal mass concept. The goal is to improve building energy efficiency and comfort levels by addressing some of the shortcomings of conventional building slabs with high thermal storage capacity. Such heavyweight constructions tend to have a slow response time and do not make use of the available thermal mass effectively. Convective Concrete explores new ways of using thermal mass in buildings more intelligently. To accomplish this ondemand charging of thermal mass, a network of ducts and fans is embedded in the concrete wall element. This is done by developing customized formwork elements in combination with advanced concrete mixtures. To achieve an efficient airflow rate, the embedded lost formwork and the concrete itself function like a lung.
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Self-Consolidating Concrete for Prestressed Bridge Girders : Research Brief
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...
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2017-06-01
The precast prestressed concrete voided slab structure is a popular bridge design because of its rapid construction and cost : savings in terms of eliminating formwork at the jobsite. However, the longitudinal shear transfer mechanism often fails, le...
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Design, Analysis And Realization Of Topology Optimized Concrete Structures
DEFF Research Database (Denmark)
Søndergaard, Asbjørn; Dombernowsky, Per
2012-01-01
This paper proposes the application of topology optimisation as a constitutive design tool for design and form-finding of architectural concrete structures, and realisation of these designs using large scale CNCmilling of polystyrene form-work for in situ casting....
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Schipper, H.R.; Grunewald, S.; Troian, S.; Raghunath, P.; Schlangen, H.E.J.G.; Copuroglu, O.; Pecur, I.B.; Baricevic, A.; Stirmer, N; Bjegovic, D.
2017-01-01
Expensive CNC (computer numerical controlled)-milled formwork is required for the production of double-curved precast concrete elements for cladding or shell structures. The innovative flexible mould method for economically efficient and sustainable production of such elements, developed at Delft
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2010-12-28
... for OMB Review; Comment Request; Concrete and Masonry Construction Standard ACTION: Notice. SUMMARY... Administration (OSHA) sponsored information collection request (ICR) titled, ``Concrete and Masonry Construction...: Construction firms engaged in the erection of concrete formwork are required to post warning signs/barriers in...
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DOUBLE CURVED SURFACE (DCS) - Case study in reinforced concrete
DEFF Research Database (Denmark)
Esteves, Luis Pedro; Henriques, Goncalo
2007-01-01
This paper deals with digital integration between design and fabrication in order to construct a complex double-curved concrete surface. This research focused on practical application of CNC technology to polyurethane (EPS), as an alternative to concrete formwork. The influence of specific EPS...
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Misol, Malte; Bloch, Christian; Monner, Hans Peter; Sinapius, Michael
2014-01-01
The sound transmission loss of lightweight structures can be increased by the application of facing formworks. In the aircraft industry this task is accomplished by means of sidewall panels (linings) mounted on the primary fuselage structure of an aircraft. At low frequencies (
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DEFF Research Database (Denmark)
Søndergaard, Asbjørn; Feringa, Jelle; Nørbjerg, Toke Bjerge
2016-01-01
This paper presents a novel method for cost-effective, robotic production of double curved formwork in Expanded Polystyrene (EPS) for in situ and prefabricated concrete construction. A rationalization and segmentation procedure is developed, which allows for the transliteration of double curved N...
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Eco-SCC: From Theory to Practical Application
Hüsken, G.; Brouwers, H.J.H.; Shui, Z.; Wu, S.; Yu, J.
2010-01-01
This paper presents the results of an experimental investigation on the application of self-compacting concrete (SCC) with reduced cement content and fine stone waste materials. Two SCC mixes containing stone waste material were designed for the application in a new formwork system developed for
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Rheological parameters used for deliberate deformation of a flexible mould after casting
Grunewald, S.; Schipper, H.R.; Raghunath, P.
2013-01-01
This paper describes how curved precast concrete elements can be manufactured in an open and reusable flexible mould. The proposed method reduces formwork costs of architectural freeform elements in concrete. First, the method is described briefly, then a series of tests are discussed, demonstrating
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estimating formwork striking time for concrete mixes estimating
African Journals Online (AJOL)
eobe
In this study, we estimated the time for strength development in concrete cured up to 56 days. Water. In this .... regression analysis using MS Excel 2016 Software performed on the ..... [1] Abolfazl, K. R, Peroti S. and Rahemi L 'The Effect of.
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2012-10-22
... of the Government of the UAE's (``GUAE''), Universal Tube and Plastic Industries, Ltd., KHK... Universal Tube and Plastic Industries, Ltd.; KHK 2.06 Scaffolding and Formwork LLC; Universal Tube and Pipe... Industry Usage Data Comment 4 Countervailability of Alita's Tariff Exemptions B. Subsidies Within the Jebel...
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29 CFR 1926.703 - Requirements for cast-in-place concrete.
2010-07-01
... 29 Labor 8 2010-07-01 2010-07-01 false Requirements for cast-in-place concrete. 1926.703 Section..., DEPARTMENT OF LABOR (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Concrete and Masonry Construction § 1926.703 Requirements for cast-in-place concrete. (a) General requirements for formwork. (1...
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Visualizing and simulating flow conditions in concrete form filling using pigments
DEFF Research Database (Denmark)
Jacobsen, Stefan; Cepuritis, Rolands; Peng, Ya
2013-01-01
Flow variation at surfaces and reinforcement during form filling was visualized with grey and black SCC. The border between grey and black (pigmented) SCC was captured as frozen images on hardened sawn- and formwork surfaces in a flow box experiment. Maximum velocity occurred at the centre of the...
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An integral design concept for ecological self-compacting concrete
Hunger, M.
2010-01-01
This Thesis addresses an alternative design concept for Self-Compacting Concrete (SCC). SCC is a special type of concrete with superior workability, which flows and compacts in all corners of a formwork just by the influence of gravity. Introduced to the concrete world in the late 1980s, SCC has
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29 CFR 1926.751 - Definitions.
2010-07-01
... point means a wall, a beam, tandem joists (with all bridging installed and a horizontal truss in the... inches (30.5 cm) in its greatest dimension in a floor, roof or other walking/working surface. Pre... floor, roof, or formwork for a floor or other walking/working surface (such as deck) which changes...
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Transition to a new generation of large natural-draught cooling towers
International Nuclear Information System (INIS)
Biller, H.; Boslau, C.; Heyde, K.; Kockelke, W.
1985-01-01
A concept of a new generation of natural-draught cooling towers for large nuclear power plant units is presented considering optimization and calculation methods, safety philosophy, dimension criteria, constructional measures, building materials, construction surveying, climbing formwork, and climbing cranes. The first installation will be available by 1990, with a unit 250 m in diameter by 150 m high
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Puente mixto para ferrocarril y carretera
Directory of Open Access Journals (Sweden)
Harris, P. C.
1963-10-01
Full Text Available This new bridge, known as the West Branch, spans the course of a river, and has a double function and two superimposed decks. One of these carries the road, and the other lower one, the railway line. It has been constructed by the Dept. of Public Works of California. The structure consists of four main spans resting on reinforced concrete piles, of great height. Four rectangular holes run down their centres. The decks consist of a continuous metal framework, made up of heavy elements, some of them weighing up to 56 tons each, was assembled in the workshop in separate sections. These were then transported to the site, to be integrated within the whole structure. In the final assembly high tensile steel bolts were employed. As the piles are very high, they are of varying cross section, according to the height. The concreting was done by means of sliding formwork, and this was sufficiently wide to ensure that the concrete was at least four hours old when the formwork passed beyond its level. To carry out these operations an auxiliary tower was built up. which supported the framework carrying the concreting tub and its pouring mechanism. From this main tub the concrete was poured into others, which placed it into the various parts of the formwork. The operation of the concrete elevator, whose motive power was provided by of the plant at ground level, was controlled by telephone between the operator of the power plant and the person responsible for distributing the concrete on the top platform. To provide the finish of the surfaces left by the sliding formwork, another platform was installed, working at a level below the lower edge of the formwork, and a similar arrangement was adopted with respect to the inner formwork for the four hollows running inside the piles.El nuevo puente, llamado West Branch, que salva el profundo cauce de un río, tiene una doble finalidad y dos tableros superpuestos: uno para carretera en la parte superior y otro para una
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International Nuclear Information System (INIS)
Kobayashi, Ichizo; Fujisawa, Soh; Nakajima, Makoto; Toida, Masaru; Nakashima, Hitoshi; Asano, Hidekazu
2011-01-01
The shotclay method is construction method of the high density bentonite engineered barrier by spraying method. Using this method, the dry density of 1.6 Mg/m 3 , which was considered impossible with the spray method, is achieved. In this study, the applicability of the shotclay method to HLW bentonite-engineered barriers was confirmed experimentally. In the tests, an actual scale vertical-type HLW bentonite-engineered barrier was constructed. This was a bentonite-engineered barrier with a diameter of 2.22 m and a height of 3.13 m. The material used was bentonite with 30% silica sand, and water content was adjusted by mixing chilled bentonite with powdered ice before thawing. Work progress was 11.2 m 3 and the weight was 21.7 Mg. The dry density of the entire buffer was 1.62 Mg/m 3 , and construction time was approximately 8 hours per unit. After the formworks were removed, the core and block of the actual scale HLW bentonite-engineered barrier were sampled to confirm homogeneity. As a result, homogeneity was confirmed, and no gaps were observed between the formwork and the buffer material and between the simulated waste and the buffer material. The applicability to HLW of the shotclay method has been confirmed through this examination. (author)
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International Nuclear Information System (INIS)
Zhang, Guo-Xing; Li, Bao-Chun; Guo, Yuan-Yuan
2015-01-01
We analyze transverse momentum spectra of K S 0 and K *0 at midrapidity in d + Au, Cu + Cu, and p+p collisions at √(s NN )=200 GeV in the formworks of Tsallis statistics and Boltzmann statistics, respectively. Both of them can describe the transverse momentum spectra and extract the thermodynamics parameters of matter evolution in the collisions. The parameters are helpful for us to understand the thermodynamics factors of the particle production
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EXPERIMENTAL STUDY ON HYBRID FIBER SELF COMPACTING CONCRETE
S. M. Leela Bharathi
2017-01-01
Self-Compacting Concrete is a recently developed concept in which the ingredients of the concrete mix are proportioned in such a way that it can flow under its own weight to completely fill the formwork and passes through the congested reinforcement without segregation and self-consolidate without any mechanical vibration. Several studies in the past have revealed the usefulness of fibres to improve the structural properties of concrete like ductility, post crack resistance, energy absorption...
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Parastesh, H.; Hajirasouliha, I.; Ramezani, R.
2014-01-01
A new ductile moment-resisting beam–column connection is developed for precast reinforced concrete (RC) frames in high seismic zones. The proposed connection provides good structural integrity in the connections and can reduce construction time by eliminating the need for formworks and welding, and minimizing cast-in-place concrete volume. A series of cyclic loading tests were carried out on six full-scale interior and exterior precast connections and two monolithic connections, all designed ...
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DEFF Research Database (Denmark)
Trempe Jr., Robert B.; Buthke, Jan
2016-01-01
This book records the efforts of a one-week joint workshop between Master students from Studio 2B of Arkitektskolen Aarhus and Master students from the Harbin Institute of Technology in Harbin, China. The workshop employed nine action words to instigate team-based investigation into the effects o...... as formwork for the shaping of wood veneer. The resulting columns ‘wear’ every aspect of this design pipeline process and display the power of process towards an architectural resolution....
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Energy Technology Data Exchange (ETDEWEB)
Maidl, B.; Edeling, H.
1981-06-11
Mechanized pushing through the rocks is possible even in teary rock if protective measures are taken directly behind the drill bit. Present arch-type supports are best reinforced with sprayed concrete as it will take up rock deformations. In this case, however, the question soon arises whether arch-type steel supports should be used at all. So far, mature solutions have not been found but they will be possible if the mining industry is really interested. Sprayed concrete with admixtures of reinforcing steel fibers plays a major role here as it will protect miner's heads already at an early stage and is suitable as support even at a later stage. Equally interesting would be reinforced concrete pumped behind advancing formwork. A combination of both techniques may turn out to be the most suitable method to replace arch-type supports. A problem of particular importance is machine bracing in the fresh concrete lining. If the concrete is filled in directly behind the drill bit, it is only 4 to 6 h old when it reaches the bracing device, i.e., its pressure resistance is lower than the contact pressure of present mining machinery. It may be difficult to find a solution here but it is considered to be possible. With shell concrete, the formwork should be constructed so as to withstand the contact pressure.
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Self-compacting concrete (SCC)
DEFF Research Database (Denmark)
Geiker, Mette Rica
2008-01-01
In many aspects Self-Compacting Concrete (SCC, “Self-Consolidating Concrete” in North America) can be considered the concrete of the future. SCC is a family of tailored concretes with special engineered properties in the fresh state. SCC flows into the formwork and around even complicated...... reinforcement arrangements under its own weight. Thus, SCC is not vibrated like conventional concrete. This drastically improves the working environment during construction, the productivity, and potentially improves the homogeneity and quality of the concrete. In addition SCC provides larger architectural...
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Peculiarities of Thermal Treatment of Monolithic Reinforced Concrete Structures
Kuchin, V. N.; Shilonosova, N. V.
2017-11-01
A mathematical program has been developed that allows one to determine the parameters of heat treatment of monolithic structures. One of the quality indicators of monolithic reinforced concrete structures is the level of temperature stresses arising in the process of heat treatment and further operation of structures. In winter at heat treatment the distribution of temperatures along the cross-section of the structure is uneven. A favorable thermo-stressed state in a concrete massif occurs when using the preheating method, providing the concrete temperature in the center of the structure is greater than at the periphery. In this case, after the strength is set and the temperature is later equalized along the cross-section, the central part of the structure tends to decrease its dimensions more but the extreme zones prevent it. Therefore, the center is in a state of tension, and the extreme zones on the periphery are compressed. In compressed concrete there is a lesser chance of cracks or defects. The temperature gradient over the section of the structure, the stress in the concrete and its strength are determined. When calculating the temperature and strength fields, the stress level was determined - a value equal to the ratio of the tensile stresses in the section under consideration to the tensile strength of the concrete in this section at the same time. The nature of the change in stress level is determined by the massive structure and power of the formwork heaters. It is shown that under unfavorable conditions the stress level is close to the critical value. The greatest temperature gradient occurs in the outer layers adjacent to the heating formwork. A technology for concrete conditioning is proposed which makes it possible to reduce the temperature stresses along the cross-section of the structure. The time for concrete conditioning in the formwork is reduced. In its turn, it further reduces labor costs and the cost of concrete work along with the cost of
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Methods of erection of high-rise buildings
Cherednichenko, Nadezhda; Oleinik, Pavel
2018-03-01
The article contains the factors determining the choice of methods for organizing the construction and production of construction and installation work for the construction of high-rise buildings. There are also indicated specific features of their underground parts, characterized by powerful slab-pile foundations, large volumes of earthworks, reinforced bases and foundations for assembly cranes. The work cycle is considered when using reinforced concrete, steel and combined skeletons of high-rise buildings; the areas of application of flow, separate and complex methods are being disclosed. The main conditions for the erection of high-rise buildings and their components are singled out: the choice of formwork systems, delivery and lifting of concrete mixes, installation of reinforcement, the formation of lifting and transporting and auxiliary equipment. The article prescribes the reserves of reduction in the duration of construction due to the creation of: complex mechanized technologies for the efficient construction of foundations in various soil conditions, including in the heaving, swelling, hindered, subsidence, bulk, water-saturated forms; complex mechanized technologies for the erection of monolithic reinforced concrete structures, taking into account the winter conditions of production and the use of mobile concrete-laying complexes and new generation machines; modular formwork systems, distinguished by their versatility, ease, simplicity in operation suitable for complex high-rise construction; more perfect methodology and the development of a set of progressive organizational and technological solutions that ensure a rational relationship between the processes of production and their maximum overlap in time and space.
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Directory of Open Access Journals (Sweden)
Heitor H. Yoshida
2007-03-01
Full Text Available The self compacting concrete is characterized by its capacity to flow inside the formwork filling it exclusively by the force of the gravity with adequate cohesion and viscosity in such a way that segregation does not occur. One of its characteristic is the presence of fines which provide the necessary cohesion,and grains with maximum diameter of 20 mm. This work presents some procedures and experimental methods that make it possible to evaluate self compacting properties of high performance concrete. First, a bibliographical review on the subject was carried out, and later, the equipment used for the accomplishment of the assays were manufactured, in order to verify the properties related to the self compacting concrete: cohesion, viscosity and segregation. As for the work, two concretes were produced with Portland ARI Cement, thick sand, stone powder, sand 0, superplasticizer made of ether-carboxilate chains that differentiate from each other for the presence of active silica in one of them and fly ash in the other. Based on the results, it was verified whether the high performance concrete had self compacting characteristics. In this case, both were considered positive. It was also analyzed the behavior of these concretes in their hardened state by means of the compressive strength test. The Self Compacting Concrete has many advantages such as: reduction in the number of employees, shorter construction period, the non-use of the vibrator and the filling of formworks with high density of… or of complex geometry.
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Athiyamaan, V.; Mohan Ganesh, G.
2017-11-01
Self-Compacting Concrete is one of the special concretes that have ability to flow and consolidate on its own weight, completely fill the formwork even in the presence of dense reinforcement; whilst maintaining its homogeneity throughout the formwork without any requirement for vibration. Researchers all over the world are developing high performance concrete by adding various Fibers, admixtures in different proportions. Various different kinds Fibers like glass, steel, carbon, Poly propylene and aramid Fibers provide improvement in concrete properties like tensile strength, fatigue characteristic, durability, shrinkage, impact, erosion resistance and serviceability of concrete[6]. It includes fundamental study on fiber reinforced self-compacting concrete with admixtures; its rheological properties, mechanical properties and overview study on design methodology statistical approaches regarding optimizing the concrete performances. The study has been classified into seven basic chapters: introduction, phenomenal study on material properties review on self-compacting concrete, overview on fiber reinforced self-compacting concrete containing admixtures, review on design and analysis of experiment; a statistical approach, summary of existing works on FRSCC and statistical modeling, literature review and, conclusion. It is so eminent to know the resent studies that had been done on polymer based binder materials (fly ash, metakaolin, GGBS, etc.), fiber reinforced concrete and SCC; to do an effective research on fiber reinforced self-compacting concrete containing admixtures. The key aim of the study is to sort-out the research gap and to gain a complete knowledge on polymer based Self compacting fiber reinforced concrete.
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Meric, Asli Duru
2015-01-01
concrete has a memory. It stores the construction sequences. It shows what it is made of and how it is made. The texture of the formwork, the color difference of the pours, and the shadows of the metal ties combine to layer the beauty of concrete. The aim of this study is to explore the instruments of a concrete surface in order to enhance this multi-sensory experience. This study began with the design of a concrete wall and evolved into the design of a single-family home. MARCH
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Puente sobre el Boiron de St. Prex, en la autopista Lausana-Ginebra
Directory of Open Access Journals (Sweden)
Suter, René
1968-04-01
Full Text Available The project consists of twin bridges, running side by side, and built one after the other. The same formwork to support reinforcement was used for both bridges, by merely moving the formwork parallel to itself, after the first bridge was completed. The bridges are of prestressed concrete, and have five spans of 56, 14, 70, 14 and 56 m, with a total length of 210 m. The deck is 2.60 m high and consists of two main girders of constant height, mutually attached by tie members, and resting on twin columns, of considerable slenderness, of reinforced concrete, and approximately 20 m high. The article describes the design procedure, the static structural calculations, the prestressing operations and some constructional details.La obra se compone de dos puentes gemelos, uno al lado del otro, construidos, sucesivamente, utilizando la misma cimbra para sostener la armadura por medio de una simple traslación lateral. Es de hormigón pretensado y comprende cinco tramos de 56, 14, 70, 14 y 56 m de luz, respectivamente, con una longitud total de 210 m. El tablero, de 2,60 m de altura, está formado por dos vigas maestras, de altura constante, unidas entre sí por tirantes y sostenidas por pilas gemelas, muy esbeltas, de hormigón armado y altura aproximada de 20 metros. El artículo describe los criterios seguidos al proyectarla, el cálculo estático de las estructuras, la fase de pretensado y algunos detalles de la construcción.
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Methods of erection of high-rise buildings
Directory of Open Access Journals (Sweden)
Cherednichenko Nadezhda
2018-01-01
Full Text Available The article contains the factors determining the choice of methods for organizing the construction and production of construction and installation work for the construction of high-rise buildings. There are also indicated specific features of their underground parts, characterized by powerful slab-pile foundations, large volumes of earthworks, reinforced bases and foundations for assembly cranes. The work cycle is considered when using reinforced concrete, steel and combined skeletons of high-rise buildings; the areas of application of flow, separate and complex methods are being disclosed. The main conditions for the erection of high-rise buildings and their components are singled out: the choice of formwork systems, delivery and lifting of concrete mixes, installation of reinforcement, the formation of lifting and transporting and auxiliary equipment. The article prescribes the reserves of reduction in the duration of construction due to the creation of: complex mechanized technologies for the efficient construction of foundations in various soil conditions, including in the heaving, swelling, hindered, subsidence, bulk, water-saturated forms; complex mechanized technologies for the erection of monolithic reinforced concrete structures, taking into account the winter conditions of production and the use of mobile concrete-laying complexes and new generation machines; modular formwork systems, distinguished by their versatility, ease, simplicity in operation suitable for complex high-rise construction; more perfect methodology and the development of a set of progressive organizational and technological solutions that ensure a rational relationship between the processes of production and their maximum overlap in time and space.
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Modelling of energy consumption at construction of high-rise buildings
Directory of Open Access Journals (Sweden)
Korol Elena
2018-01-01
Full Text Available High-rise building structures in the course of its erection suppose primary use of methods provided for erection, concrete and external finishing works. Erection works do not differ significantly from usual ones: traditional equipment, accessories and techniques are used which are based on erection of structures in project position using a crane. Structures to be assembled in building frame include steel columns and beams, wall panels, form elements of columns, walls and floor structures. We can note heightened attention to operational control for quality of erection, but it is attributable to all works in the course of high-rise construction. During high-rise erection by means of cast in-situ reinforced concrete all formworks to be used do not have any special differences except systems specially designed for high-rise erection using sliding formwork or vertical traveling forms. In these systems special attention is paid to safety of elevated works. Working methods of placement and curing of concrete and structures as a whole remain traditional – the requirements for controlling such operations become toughened. The most evident differences in high-rise erection with regard to equipment, machinery and accessories used are in means provided for load transportation and safety of works at heights. Particularity of internal finishing works which are also obligatory during construction of skyscrapers allows not considering them in as technological differences from usual construction as far as the «height» of its execution is limited by height of particular floor and determined by price and building class.
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Modelling of energy consumption at construction of high-rise buildings
Korol, Elena; Korol, Oleg
2018-03-01
High-rise building structures in the course of its erection suppose primary use of methods provided for erection, concrete and external finishing works. Erection works do not differ significantly from usual ones: traditional equipment, accessories and techniques are used which are based on erection of structures in project position using a crane. Structures to be assembled in building frame include steel columns and beams, wall panels, form elements of columns, walls and floor structures. We can note heightened attention to operational control for quality of erection, but it is attributable to all works in the course of high-rise construction. During high-rise erection by means of cast in-situ reinforced concrete all formworks to be used do not have any special differences except systems specially designed for high-rise erection using sliding formwork or vertical traveling forms. In these systems special attention is paid to safety of elevated works. Working methods of placement and curing of concrete and structures as a whole remain traditional - the requirements for controlling such operations become toughened. The most evident differences in high-rise erection with regard to equipment, machinery and accessories used are in means provided for load transportation and safety of works at heights. Particularity of internal finishing works which are also obligatory during construction of skyscrapers allows not considering them in as technological differences from usual construction as far as the «height» of its execution is limited by height of particular floor and determined by price and building class.
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The ACR: Advanced design features for a short construction schedule
International Nuclear Information System (INIS)
Elgohary, M.; Fairclough, N.
2003-01-01
Building on the successful CANDU construction at Qinshan, the ACR-700 is designed with constructability considerations as a major requirement during all project phases from the concept design stage to the detail design stage. A project schedule of 48 months has been developed for the nth ACR unit with a 36 months construction period from First Concrete to Fuel Load. This paper describes some of the advanced design features implemented in the reactor building design in order to achieve this short construction period. These features include large volume concrete pours, prefabricated rebar, composite structures, prefabricated permanent formwork and significant modularization and prefabrication
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Self-Compacting Concrete in Precast Elements Industry
Directory of Open Access Journals (Sweden)
Corneliu Bob
2005-01-01
Full Text Available In this paper the authors present information about the Self-Compacting Concrete and experimental results regarding the use of them into precast element industry. This type of concrete does not require vibration for placing and compaction; it is able to flow under its own weight, completely filling formwork and achieving full compaction, even in the presence of congested reinforcement. The experimental programme has take into account two prestressed beams which were prefabricated and tested on a special stands. The beams of Self-Compacting Concrete with the length of 24 m were prepared at „Beton-Star” Kft, Kecsekenet, Hungary, and used at the CASCO, Satu-Mare.
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International Nuclear Information System (INIS)
Friedrich, F.
1987-01-01
Containments consisting of steel modules have been developed as an alternative design and solution to the double shell containments comprising two separate structures. The combination of different reinforcement layers of steel plates and round reinforcing bars in one cross section provides a high loadbearing capacity. The multiple utilization of the steel plates in the composite section as formwork in the construction state and as reinforcement and liner in the operation or damage/failure states, respectively, yields a number of advantages. The main effect is being achieved due to the high degree of prefabrication and completion (finishing) of the steel modules and the reduction of expenditure on the job site connected with same. (orig.)
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Experiences from the design and construction of plug II in the Prototype Repository
Energy Technology Data Exchange (ETDEWEB)
Dahlstroem, Lars-Olof (NCC Teknik (Sweden))
2009-12-15
The intention with this document is to summarise the comprehensive documentation and experience that was gained during the design and construction of the temporary plugs in the Prototype Repository experiment at Aespoe HRL. The Prototype Repository experiment was designed to in full scale test the engineered barriers and their function, including the plug that separate the deposition tunnel from the temporary access- and transportation tunnels that are at atmospheric pressure. This plug is designed and constructed as a concrete plug with a spherical front side and a flat pressurised side. This report presents the processes and operations that were considered when developing the 'plug', design, construction and verification. In the Prototype Repository the demand of leakage control is very high and the maximum length of the plugs is constrained due to available clearance space, experimental set-up and configuration. Therefore a typical 'friction plug' normally used to block waterways in connection with hydropower plants, is not suitable. Instead a plug constructed as an 'arch plug' with abutments was considered. In order to minimize the Excavation Disturbed Zone (EDZ) the abutments, in which the plug is inserted, was excavated by seam drilling with coring technique. The steel formwork was pre-assembled at the ground surface before taken down to the tunnel. The steel was bolted and welded together and crossbars and plywood were mounted on top. Before taken down to the tunnel, the formwork was separated into smaller pieces that were easier to transport down the tunnel but easy to assembly at the Prototype Repository experiment. Before assembling the formwork, a retaining wall was installed to resist the earth and compaction pressure developed from the backfill material. The retaining wall consists of pre-fabricated concrete beams that were installed parallel with the installation of the backfill. Reinforcement was cut and bent at the
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Experiences from the design and construction of plug II in the Prototype Repository
International Nuclear Information System (INIS)
Dahlstroem, Lars-Olof
2009-12-01
The intention with this document is to summarise the comprehensive documentation and experience that was gained during the design and construction of the temporary plugs in the Prototype Repository experiment at Aespoe HRL. The Prototype Repository experiment was designed to in full scale test the engineered barriers and their function, including the plug that separate the deposition tunnel from the temporary access- and transportation tunnels that are at atmospheric pressure. This plug is designed and constructed as a concrete plug with a spherical front side and a flat pressurised side. This report presents the processes and operations that were considered when developing the 'plug', design, construction and verification. In the Prototype Repository the demand of leakage control is very high and the maximum length of the plugs is constrained due to available clearance space, experimental set-up and configuration. Therefore a typical 'friction plug' normally used to block waterways in connection with hydropower plants, is not suitable. Instead a plug constructed as an 'arch plug' with abutments was considered. In order to minimize the Excavation Disturbed Zone (EDZ) the abutments, in which the plug is inserted, was excavated by seam drilling with coring technique. The steel formwork was pre-assembled at the ground surface before taken down to the tunnel. The steel was bolted and welded together and crossbars and plywood were mounted on top. Before taken down to the tunnel, the formwork was separated into smaller pieces that were easier to transport down the tunnel but easy to assembly at the Prototype Repository experiment. Before assembling the formwork, a retaining wall was installed to resist the earth and compaction pressure developed from the backfill material. The retaining wall consists of pre-fabricated concrete beams that were installed parallel with the installation of the backfill. Reinforcement was cut and bent at the factory and was ready for
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Quality evaluation of concrete under compacting by vibration using resistance of electro current
International Nuclear Information System (INIS)
Nozaki, Yoshisugu
2006-01-01
Quality of concrete in structures is affected not only quality of materials; i.e. fresh concrete delivered to site but also placing and compaction works. Factors related to the latter are not studied minutely, and the works in site are judged and controlled by skilled person under his experience, and these process are said to the neck in QC and rationalization in construction site. The study to develop the evaluation system of fresh concrete quality is described in the paper, In the experiment, electrode was attached to formwork and resistance of electro current was recorded while vibrating. It can recognized that resistance is closely related to internal quality of concrete, so the resistance may be the effective index to know optimum compaction time in placing work.
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The effect of surface treatment on the microstructure of the skin of concrete
Sadowski, Łukasz; Stefaniuk, Damian
2018-01-01
The aim of this study is to better understand the heterogeneity and microstructural properties of the skin of concrete. The microstructural evaluation of the skin of concrete was performed using X-ray micro computed tomography (micro-CT). The concrete surface was treated using four methods, due to which different surfaces were obtained, i.e. a raw surface, a surface formed after contact with formwork, a grinded surface and also a shotblasted surface. The results of the pore structure obtained from the micro-CT images were used to assess the influence of selected surface treatment method on the nature of the skin of concrete. It was shown that the thickness and unique nature of the skin of concrete differ for various surface treatment methods.
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Construcción de un pavimento rígido con máquina de encofrado deslizante en la autopista París-Lyon
Directory of Open Access Journals (Sweden)
García Meseguer, Álvaro
1963-12-01
Full Text Available This article describes the construction of a mass concrete pavement, carried out with the aid of a Gunter-Zimmermann sliding formwork, manufactured in the United States. This device guides itself automatically by means of an electronic control, and does the following set of operations simultaneously: it spreads the concrete over the whole width of the pavement (7.5 ms; vibrates it; shapes it and gives it the final thickness with the aid of the sliding formwork; it provides a longitudinal cut, which serves as a dilation joint; fills this joint with plastic material; places connecting reinforcements across the joint, half way down the depth of the pavement; and smoothes out the final surface. The author refers to the final surface finish; discusses the sawing of the transversal joints, various tests and checks, and the possibilities and limitations of this constructional procedure. He finishes by enumerating some general inferences on this method of road construction.Se describe la ejecución de un pavimento de hormigón en masa con la máquina de encofrado deslizante Gunter-Zimmerman, de fabricación norteamericana. Esta máquina, que se guía automáticamente por medio de contactos electrónicos, realiza, sin solución de continuidad, las siguientes operaciones: reparte el hormigón a todo ancho (7,50 m, lo vibra, le da forma y espesor definitivos en su encofrado deslizante, ejecuta una ranura longitudinal que actúa de junta, rellena esa ranura con una cinta de plástico, introduce unas armaduras de cosido de la junta a medio espesor de la losa e iguala la superficie final. Después de referirse al acabado superficial, al curado, a la ejecución por aserrado de juntas transversales y a diversos ensayos y comprobaciones, analiza el autor las posibilidades y limitaciones de este procedimiento, llegando a las conclusiones que aparecen al final del texto.
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Hacia una taxonomía constructiva de las tapias de tierra y fábricas encofradas históricas
Directory of Open Access Journals (Sweden)
Gil-Crespo, I. J.
2015-06-01
Full Text Available The principal aim of the research is the study of the constructive reasons of the historical masonries built with rammed earth and formwork masonry, belonging to late medieval fortifications. Uncertainties have been warned about dating the historical masonries and there are excessive exceptions that do not fall in the rankings traditionally employed to study these techniques. Due to these reasons, the article develops a proposal of constructive typology or taxonomy based in an open system that comes from the analysis of a representative number of masonries and that attends to several control parameters tor the complete characterization of each masonry: material, compaction degree, constructive function, formwork, rendering, combination of materials and, last, the situation, deepness, formation and section of the putlogholes. Each masonry is classified through an alphanumeric label. The system allows establishing several constructive types which it is possible to do a cronotypological and constructive classification.El objetivo fundamental de la investigación es el estudio de los fundamentos constructivos de las fábricas históricas de tapia de tierra y mampostería encofrada de las fortificaciones bajomedievales. Ante las incertidumbres detectadas en la datación de estas estructuras y frente al excesivo número de excepciones que quedan fuera de las clasificaciones tradicionalmente empleadas para estudiar este tipo de técnicas, el artículo desarrolla una propuesta de tipología o taxonomía constructiva basada en un sistema abierto. Este sistema nace del análisis de un número significativo de fábricas y atiende a diversos parámetros de control para la completa caracterización de cada fábrica: material, grado de compactación, función constructiva, encofrado, acabado superficial, combinación de materiales y situación, profundidad, formación y sección de los agujales. Cada fábrica se clasifica mediante una etiqueta alfanum
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Flow modelling of steel fibre reinforced self-compacting concrete
DEFF Research Database (Denmark)
Svec, Oldrich
was done by means of the Immersed boundary method with direct forcing. Evolution of the immersed particles was described by Newton's differential equations of motion. The Newton's equations were solved by means of Runge-Kutta-Fehlberg iterative scheme. Several challenges had to be overcome during...... in concrete can efficiently substitute or supplement conventional steel reinforcement, such as reinforcement bars. Ordinary concrete composition further makes the material stiff and non-flowable. Self-compacting concrete is an alternative material of low yield stress and plastic viscosity that does flow...... of the fluid near formwork surface. A method to incorporate the apparent slip into the Lattice Boltzmann fluid dynamics solver was suggested. The proposed numerical framework was observed to correctly predict flow of fibre reinforced self-compacting concrete. The proposed numerical framework can therefore...
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DEFF Research Database (Denmark)
2017-01-01
projects - among others - from ARC are included: Soft Structures builds upon of a series of experimental use of EPS hot wire cutting, where the EPS eventually act as formwork for concrete casting. The processing of the EPS is distinct and delimited by the behaviour and form of both the robot and tool...... of steel and concrete makes it a reliable approach to many challenges in the realisation of buildings. Rebar Inside Out attempts to rethink the possibilities of the reinforced concrete composite starting from its inside. This means starting with the reinforcing steel, the production and shaping of this......, and then through that process build a workflow for the production of the concrete composite. It also means letting the steel out of the concrete, thereby positioning the two materials in a transnational relationship between steel construction and concrete composite....
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Development and Evaluation of Mould for Double Curved Concrete Elements
DEFF Research Database (Denmark)
Jepsen, Christian Raun; Kristensen, Mathias Kræmmergaard; Kirkegaard, Poul Henning
2011-01-01
freeform concrete formwork are available, and more are being developed [1-4]. The common way of producing moulds for unique elements today is to manufacture one mould for each unique element using CNC milling in cheaper materials, but since the method is still labour intensive and produces a lot of waste......Complex freeform architecture is one of the most striking trends in contemporary architecture. Architecture differs from traditional target industries of CAD/CAM technology in many ways including aesthetics, statics, structural aspects, scale and manufacturing technologies. Designing a piece...... of freeform architecture in a CAD program is fairly easy, but the translation to a real piece of architecture can be difficult and expensive and as traditional production methods for free-form architecture prove costly, architects and engineers are forced to simplify designs. Today, methods for manufacturing...
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Viaducto de Chonta en la autopista Bilbao-Behobia – España
Directory of Open Access Journals (Sweden)
Aparicio, G.
1974-03-01
Full Text Available Located in the Bilbao-Behobia motorway, passing through Eibar, it has a curved layout and supports two carriageways of 11.5 m in width. The flooring is made up of two bracket spans,, of 52 m each, made on site, and by another two, of 43 m each, formed by five prestressed prefabricated girders; the two abutments are conventional. We would stress the curious construction of the formwork, for the in situ spans, and launching of the 43 m girders with 120 t 45 m. Sicet cart, carried out by Ferrovial, S. A. The sloping piles —18 m apart in the middle line in their upper part and 4 in the foundations— are, however, the most original and interesting feature of this work. In order to be able to use the sliding formwork and avoid building side timbering and which hamper traffic below, they were made in a vertical position, subsequently opening, rotating on metal ball-joints With this type of piles, the initial span of 95 m is reduced to 77 m.Situado en la autopista Bilbao-Behobia, a su paso por Eibar, presenta un trazado en curva y soporta dos calzadas de 11,50 m de anchura. El tablero está constituido por dos tramos ménsula, de 52 m cada uno, fabricados in situ, y por otros dos, de 43 m, formados por cinco vigas prefabricadas pretensadas; los dos estribos son tradicionales. Destacamos la curiosa construcción de los encofrados, para los tramos in situ, y el lanzamiento de las vigas de 43 m con carro Sicet de 120 t y 45 m, realizada por Ferrovial, S. A. Las pilas inclinadas —18 m de separación de medianas en su parte alta y 4 en cimientos— son, sin embargo, la nota más original e interesante de esta obra, ya que para poder utilizar los encofrados deslizantes y evitar la construcción de apeos costosos y entorpecedores del tráfico inferior se realizaron en posición vertical, abriéndose, posteriormente, con giro sobre rótulas metálicas. Con este tipo de pilas se reduce la luz inicial de 95 m a 77 m.
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Arquitectura de tierra -histórica y moderna- en Italia
Directory of Open Access Journals (Sweden)
Galdieri, Eugenio
1986-02-01
Full Text Available This work about the history of mud constructions in Italy -both of brick and formwork- gives an exposition of geographical zones where those are located, the kind of uses so as their possible historic origins, among which the author points the strong connections with Spanish adobe constructions, both in Cagliars (Aragonese influence and in Oristano (Castilian influence.El trabajo de carácter histórico sobre las construcciones con tierra en Italia, tanto de adobe como de tapial presenta una panorámica de las zonas geográficas en las que se encuentran enclavadas, así como el tipo de usos y posibles orígenes históricos, entre los que el autor señala los fuertes vínculos con las construcciones de tierra españolas, tanto en Cagliaria (influencia aragonesa como en Oristano (influencia castellana.
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Behavior of Equipment Support Beam Joint Directly Connected to A Steel-plate Concrete(SC) Wall
International Nuclear Information System (INIS)
Kim, K. S.; Kwon, K. J.
2008-01-01
To decrease the time for building nuclear power plants, a modular construction method, 'Steel-plate Concrete(SC)', has been investigated for over a decade. To construct a SC wall, a pair of steel plates are placed in parallel similar to a form-work in conventional reinforced concrete (RC) structures, and concrete is filled between the steel plates. Instead of removing the steel plates after the concrete has cured, the steel plates serve as components of the structural member. The exposed steel plate of SC structures serves as the base plate for the equipment support, and the headed studs welded to the steel plates are used as anchor bolts. Then, a support beam can be directly welded to the surface of the steel plate in any preferred position. In this study, we discuss the behavior and evaluation method of the equipment support joint directly connected to exposed steel plate of SC wall
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The use of nanomodified concrete in construction of high-rise buildings
Prokhorov, Sergei
2018-03-01
Construction is one of the leading economy sectors. Currently, concrete is the basis of most of the structural elements, without which it is impossible to imagine the construction of a single building or facility. Their strength, reinforcement and the period of concrete lifetime are determined at the design stage, taking into account long-term operation. However, in real life, the number of impacts that affects the structural strength is pretty high. In some cases, they are random and do not have standardized values. This is especially true in the construction and exploitation of high-rise buildings and structures. Unlike the multi-storey buildings, they experience significant loads already at the stage of erection, as they support load-lifting mechanisms, formwork systems, workers, etc. The purpose of the presented article is to develop a methodology for estimating the internal fatigue of concrete structures based on changes in their electrical conductivity.
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DEFF Research Database (Denmark)
Cortsen, Jens
Denne afhandling præsenterer vores arbejde i det danske projekt Unique Concrete Structures (Unikabeton) and EU projekt TailorMade Concrete Structures (TailorCrete) med at automatisere udvalgte processer for konstruktion af unike beton bygninger. Vi har primært fokus på robotfræsning af komplekse...... dobbeltkurvede armerings gitter med to samarbejdende robotter, hvor delprocesserne er bøjning, transportering og binding af ameringsstænger. Robotinstallationen er baseret på et off-line simuleringsprogram med dynamisk simulerings support for stangnedbøjning og samtidigt robot control for at reducere...... produktionstiden. De to mindre processer som varmetråd skæring af EPS blokke før fræsning og sprøjtning af slipmiddel på de færdige formwork blokke er også præsenteret efter de to hoved processer. Til sidst præsenterer vi en række af real life betonstrukturer baseret på vores arbejde i denne afhandling...
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Problems of magnesium oxide wallboard usage in construction
Gravit, Marina; Zybina, Olga; Vaititckii, Artem; Kopytova, Anna
2017-10-01
Magnesium oxide wallboard is the building and finishing material, which has a reputation of new generational ecological constructing material. It has a wide range of uses: as a revetment in ventilated facades’ production, as a decorative material, as different types of formworks for a foundation filling and as a protector against a fire threat. During the study it was considered that magnesium oxide wallboards have some defects, such as moisture formation as a concentrated brine on the surface under special climatic conditions and absence of clear distinguishing between different types of magnesia boards. Usage of this material can become a cause of frame’s corrosion and origin of mold on wooden details. Authors provide the information from a foreign data source about negative consequences of SML usage. In conclusion researchers state that it is necessary to provide a clear magnesium wallboards classification and define technical requirements, which will, in their opinion, lead to Russian standard formulation.
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Large Scale Glazed Concrete Panels
DEFF Research Database (Denmark)
Bache, Anja Margrethe
2010-01-01
Today, there is a lot of focus on concrete surface’s aesthitic potential, both globally and locally. World famous architects such as Herzog De Meuron, Zaha Hadid, Richard Meyer and David Chippenfield challenge the exposure of concrete in their architecture. At home, this trend can be seen...... in the crinkly façade of DR-Byen (the domicile of the Danish Broadcasting Company) by architect Jean Nouvel and Zaha Hadid’s Ordrupgård’s black curved smooth concrete surfaces. Furthermore, one can point to initiatives such as “Synlig beton” (visible concrete) that can be seen on the website www.......synligbeton.dk and spæncom’s aesthetic relief effects by the designer Line Kramhøft (www.spaencom.com). It is my hope that the research-development project “Lasting large scale glazed concrete formwork,” I am working on at DTU, department of Architectural Engineering will be able to complement these. It is a project where I...
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Gholamhoseini, Alireza
2016-03-01
Relatively little research has been reported on the time-dependent in-service behavior of composite concrete slabs with profiled steel decking as permanent formwork and little guidance is available for calculating long-term deflections. The drying shrinkage profile through the thickness of a composite slab is greatly affected by the impermeable steel deck at the slab soffit, and this has only recently been quantified. This paper presents the results of long-term laboratory tests on composite slabs subjected to both drying shrinkage and sustained loads. Based on laboratory measurements, a design model for the shrinkage strain profile through the thickness of a slab is proposed. The design model is based on some modifications to an existing creep and shrinkage prediction model B3. In addition, an analytical model is developed to calculate the time-dependent deflection of composite slabs taking into account the time-dependent effects of creep and shrinkage. The calculated deflections are shown to be in good agreement with the experimental measurements.
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Setareh, Mehdi
2017-01-01
This revised, fully updated second edition covers the analysis, design, and construction of reinforced concrete structures from a real-world perspective. It examines different reinforced concrete elements such as slabs, beams, columns, foundations, basement and retaining walls and pre-stressed concrete incorporating the most up-to-date edition of the American Concrete Institute Code (ACI 318-14) requirements for the design of concrete structures. It includes a chapter on metric system in reinforced concrete design and construction. A new chapter on the design of formworks has been added which is of great value to students in the construction engineering programs along with practicing engineers and architects. This second edition also includes a new appendix with color images illustrating various concrete construction practices, and well-designed buildings. The ACI 318-14 constitutes the most extensive reorganization of the code in the past 40 years. References to the various sections of the ACI 318-14 are pro...
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Directory of Open Access Journals (Sweden)
Andrei Gheorghe
2017-09-01
Full Text Available This full-scale research pavilion exercises the application of timber and polymer concrete in architectural production (Figure 1. It attempts to develop and test a new hybrid construction technique using composite joints [as introduced in Schober et al. (2014] within a modular geometric system and no need for formwork. The structure was designed and erected by students and instructors of the Digital Design and Full-Scale Fabrication seminar taught at the Institute of Architecture, University of Applied Arts Vienna. CNC milled, 3-layer spruce laminated timber boards are used for construction, which are temporarily fixed, then rigidized with polymer concrete. The cured composite node proves high structural capabilities, as polymer concrete withstands both pressure and tensile forces, and the bond between the materials is as strong as the wood itself. Compared to traditional timber construction, no metal bolting is needed for the creation of the node, while at the same time, the node geometry becomes more flexible, meaning any three-dimensional layout can be produced, as long as a temporary containment and fixation can be implemented until the chemical curing process is completed (Schober et al., 2016. The geometry is developed as an interpretation of the Zollinger (Menges et al., 2016 grid, where members originally are of twice the grid length (Figure 2 and reciprocally reliant on each other (Figure 3. Instead, every second grid cell is made a joint node when cast out with concrete, making the structural members a lost formwork at the same time (Figure 4. Double-layering each member (see detail explanation of the construction process in Section “Construction Method” below makes it possible to cast all 122 nodes of the pavilion structure separately and flat-bolt them together on-site with metal screws. Alternative fixation techniques (i.e., glue of the nodes can be tested in future. The software plugin RhinoVault is used as a design tool to
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Temperature effects on bond between concrete and reinforcing steel
Directory of Open Access Journals (Sweden)
Lublóy Éva
2014-01-01
Full Text Available Bond behaviour between concrete and reinforcing bars was observed under elevated temperatures. Five different concrete compositions were used. Hundred five pull-out specimens (Ø120 mm, 100 mm were prepared. After removing the specimens from the formwork, they were stored in water for seven days then kept at laboratory conditions until testing. The specimens were 28 days old by testing. After heating up the specimens, they were kept for two hours at these maximum temperatures (20 °C, 150 °C, 300 °C, 400 °C, 500 °C, 800 °C. Specimens were then cooled down in laboratory conditions. Finally the specimens were tested at room temperature. In order to check the compressive strength standard cubes were cast, cured, and heat treated, then tested to compressive strength. The results showed reduction in residual compressive strength and considerable changes in steel-concrete bond under high temperatures. Based on test results, a proposal is presented for the modification of MC2010 bond-ship formula in order to consider temperature effect.
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Directory of Open Access Journals (Sweden)
García Ordoñez, Fernando
1968-05-01
Full Text Available This church design is based on the idea of enclosed and concentrated thought. Its light source is zenithal, from skylights at the top of the structure. It is shaped like a sailing boat, without comers or sharp edges, and seeks to enclose a smoothly contoured space, as most suitable to establish a mental encounter with the Almighty. The whole project is in concrete; the formwork being of exceptional quality. Both its formal concept emd its external and internal aspects make this a notable design, that is outstanding in modem religious architecture.Esta original iglesia ha surgido de una idea de interioridad, con total iluminación interior cenital, desde los lucernarios superiores. Su forma es la de una barca, sin esquinas, suave, como espacio más adecuado para un encuentro con Dios. Toda la obra es de hormigón vertido en encofrados maravillosamente realizados y, tanto su concepción formal como el tratamiento dado a sus interiores y exteriores, la destacan, notablemente, en el campo de la Arquitectura religiosa contemporánea.
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Modeling Manpower and Equipment Productivity in Tall Building Construction Projects
Mudumbai Krishnaswamy, Parthasarathy; Rajiah, Murugasan; Vasan, Ramya
2017-12-01
Tall building construction projects involve two critical resources of manpower and equipment. Their usage, however, widely varies due to several factors affecting their productivity. Currently, no systematic study for estimating and increasing their productivity is available. What is prevalent is the use of empirical data, experience of similar projects and assumptions. As tall building projects are here to stay and increase, to meet the emerging demands in ever shrinking urban spaces, it is imperative to explore ways and means of scientific productivity models for basic construction activities: concrete, reinforcement, formwork, block work and plastering for the input of specific resources in a mixed environment of manpower and equipment usage. Data pertaining to 72 tall building projects in India were collected and analyzed. Then, suitable productivity estimation models were developed using multiple linear regression analysis and validated using independent field data. It is hoped that the models developed in the study will be useful for quantity surveyors, cost engineers and project managers to estimate productivity of resources in tall building projects.
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FEM simulation of static loading test of the Omega beam
Bílý, Petr; Kohoutková, Alena; Jedlinský, Petr
2017-09-01
The paper deals with a FEM simulation of static loading test of the Omega beam. Omega beam is a precast prestressed high-performance concrete element with the shape of Greek letter omega. Omega beam was designed as a self-supporting permanent formwork member for construction of girder bridges. FEM program ATENA Science was exploited for simulation of load-bearing test of the beam. The numerical model was calibrated using the data from both static loading test and tests of material properties. Comparison of load-displacement diagrams obtained from the experiment and the model was conducted. Development of cracks and crack patterns were compared. Very good agreement of experimental data and the FEM model was reached. The calibrated model can be used for design of optimized Omega beams in the future without the need of expensive loading tests. The calibrated material model can be also exploited in other types of FEM analyses of bridges constructed with the use of Omega beams, such as limit state analysis, optimization of shear connectors, prediction of long-term deflections or prediction of crack development.
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Proportioning and performance evaluation of self-consolidating concrete
Wang, Xuhao
A well-proportioned self-consolidating concrete (SCC) mixture can be achieved by controlling the aggregate system, paste quality, and paste quantity. The work presented in this dissertation involves an effort to study and improve particle packing of the concrete system and reduce the paste quantity while maintaining concrete quality and performance. This dissertation is composed of four papers resulting from the study: (1) Assessing Particle Packing Based Self-Consolidating Concrete Mix Design; (2) Using Paste-To-Voids Volume Ratio to Evaluate the Performance of Self-Consolidating Concrete Mixtures; (3) Image Analysis Applications on Assessing Static Stability and Flowability of Self-Consolidating Concrete, and (4) Using Ultrasonic Wave Propagation to Monitor Stiffening Process of Self-Consolidating Concrete. Tests were conducted on a large matrix of SCC mixtures that were designed for cast-in-place bridge construction. The mixtures were made with different aggregate types, sizes, and different cementitious materials. In Paper 1, a modified particle-packing based mix design method, originally proposed by Brouwers (2005), was applied to the design of self-consolidating concrete (SCC) mixs. Using this method, a large matrix of SCC mixes was designed to have a particle distribution modulus (q) ranging from 0.23 to 0.29. Fresh properties (such as flowability, passing ability, segregation resistance, yield stress, viscosity, set time and formwork pressure) and hardened properties (such as compressive strength, surface resistance, shrinkage, and air structure) of these concrete mixes were experimentally evaluated. In Paper 2, a concept that is based on paste-to-voids volume ratio (Vpaste/Vvoids) was employed to assess the performance of SCC mixtures. The relationship between excess paste theory and Vpaste/Vvoids was investigated. The workability, flow properties, compressive strength, shrinkage, and surface resistivity of SCC mixtures were determined at various ages
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Autopista Ronda-Oeste de Murcia – España
Directory of Open Access Journals (Sweden)
Editorial, Equipo
1977-10-01
Full Text Available The Ronda-West expressway in Murcia detours the traffic of route CN-301, from Madrid to Cartagena, around the center of the city, thereby facilitating the routing of vehicular traffic. This expressway consists of two access roads, four cloverleaves, three viaducts, two elevated bypasses and a large amount of masonry work. The structures are built with post-stressed beams, replaced in some stretches by prestressed slabs or also post-stressed slabs, and abutments made with formwork. The foundations have been laid over piles in situ.La autopista Ronda- Oeste de Murcia evita el paso del tráfico de la carretera CN-301, de Madrid a Cartagena, por el centro de la ciudad, con lo que facilita la ordenación de la circulación rodada. Dicha autopista consta de dos enlaces, cuatro nudos, tres viaductos, dos pasos elevados y una gran obra de fábrica. Las estructuras están realizadas a base de vigas postensadas, sustituidas en algunos tramos por losas pretensadas o también postensadas y estribos realizados con cimbra. La cimentación se ha hecho sobre pilotes in situ.
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Los viaductos de acceso al puente de Martigues – Francia
Directory of Open Access Journals (Sweden)
Perzo, R.
1972-11-01
Full Text Available This article describes the approaches to a large metal bridge 300 m in length. These approaches consist of two viaducts whose decks are continuous beams of prestressed concrete 260 and 315 m long; spans in both viaducts are 45 m long. The cross section is a slab with two 3 m deep ribs; there are no stiffeners, neither between the spans nor over the supports. The two structures have been constructed with spans of 45 m over a self-supporting formwork which has proven very efficient.Se describen los accesos a un gran puente metálico, de 300 m de longitud. Dichos accesos están constituidos por dos viaductos cuyos tableros son vigas continuas, de hormigón pretensado, de 260 y 315 m de longitud; las luces en ambos viaductos son de 45 m. La sección transversal es una losa con dos nervios de 3 m de canto; no existen riostras ni en los vanos ni sobre los apoyos. Las dos estructuras se han construido por tramos de 45 m sobre una cimbra autolanzable, que ha permitido muy buenos rendimientos.
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Occupational risk of building construction
International Nuclear Information System (INIS)
Aneziris, O.N.; Topali, E.; Papazoglou, I.A.
2012-01-01
This paper presents the quantification of occupational risk of a building construction project. Risk assessment is based on the Occupational Risk Model (ORCA) developed under the Workgroup Occupational Risk Model project (WORM), in the Netherlands, for quantifying occupational risk. This model assesses occupational risk of a worker, by taking into account his various tasks, activities and their hazards. Risk is evaluated for three types of consequences: recoverable injury, permanent injury and death. The occupational risk model is based on a set of 63 bowties, which assess risk owing to different hazards such as fall from ladder, scaffold, roofs, falling object, struck by moving vehicle, contact by moving parts, etc. ORCA calculates the risk profile of a building construction site, consisting of thirty-eight workers in different job positions, such as operators of excavators, loaders, compaction equipment, workers in excavation and framing phases, etc. All risk profiles of workers have been quantified and jobs have been ranked according to their risk. Workers installing timber formworks have the highest fatality risk (1.57×10 −3 /yr), followed by the workers installing reinforcement (1.52×10 −3 /yr).
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FE Modelling of the Seismic Behavior of Wide Beam-Column Joints Strengthened with CFRP Systems
Directory of Open Access Journals (Sweden)
Giuseppe Santarsiero
2018-02-01
Full Text Available A large share of reinforced concrete (RC framed buildings is provided with wide beams being a type of beam allowing greater freedom in the architectural arrangement of interiors, beyond further advantage due to fewer formworks needed during the construction. Nevertheless, little attention has been devoted to the seismic vulnerability of this kind of framed RC buildings as well as to the study of strengthening systems purposely developed for wide beams and wide beam-column connections. Under these premises, this paper proposes simple strengthening solutions made by Fibre Reinforced Polymers (FRP systems able to effectively improve seismic capacity through feasible arrangement suitable in case a wide beam is present. On the basis of wide beam-column joints previously tested without strengthening system, detailed nonlinear finite element models were calibrated. Then, an FRP strengthening intervention based on a brand new arrangement was modeled in order to perform additional simulations under seismic actions. This way, the effectiveness of the strengthening intervention was assessed finding out that significant strength and ductility increments were achieved with a relatively simple and cheap strengthening arrangement. Additional research would be desirable in the form of experimental tests on the simulated wide beam-column joints.
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Disk shaped radiation sources for education purposes made of chemical fertilizer
International Nuclear Information System (INIS)
Kawano, Takao
2008-01-01
A method for fabricating a disk-shaped radiation source from material containing natural radioisotopes was developed. In this compression and formation method, a certain amount of powdered material is placed in a stainless steel formwork and compressed to form a solid disk. Using this method, educational radiation sources were fabricated using commercially available chemical fertilizers that naturally contain the radionuclide, 40 K, which emits either beta or gamma rays, at each disintegration. The compression and formation method was evaluated by inspecting eleven radiation sources thus fabricated. Then the suitability of the fertilizer radiation source as an education aid was evaluated. The results showed that the method could be used to fabricate radiation sources without the need for learning special skills or techniques. It was also found that the potassium fertilizer radiation source could be used to demonstrate that the inverse-square law can be applied to the distance between the radiation source and detector, and that an exponential relationship can be seen between the shielding effectiveness and the total thickness of the shielding materials. It is concluded that a natural fertilizer radiation source is an appropriate aid for demonstrating the characteristics of radiation. (author)
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Viaductos de hormigón pretensado construidos por vanos sucesivos
Directory of Open Access Journals (Sweden)
Wittfoht, Hans
1968-12-01
Full Text Available The difficulties involved in the use of traditional formwork in the case of certain types of prestressed bridges have led to the adoption of new methods, to overcome these difficulties, though retaining or improving the existing standars of safety, cost and speed. The launching devices seem to meet these needs and are being used with increasing success, particularly in German motor road bridges of all types, of a variety of spans and resting on many kinds of soils: sometimes under the most adverse conditions.Las dificultades que presentaba la utilización de las cimbras tradicionales al construir ciertos puentes de hormigón pretensado han forzado a encontrar una solución que superase los inconvenientes, conservando, o mejorando a ser posible, todas las ventajas en orden a seguridad, rapidez, economía, etc. Los andamiajes de lanzamiento parecen llenar todos los requisitos impuestos y han venido empleándose con éxito creciente, especialmente en las autopistas alemanas, en puentes de todos los tipos—con luces muy diversas y asentados sobre toda clase de terrenos—, algunos de los cuales presentaban las condiciones más desfavorables.
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Directory of Open Access Journals (Sweden)
Salas, J.
1986-02-01
Full Text Available In this work, some of the experimental housing works (blocks, formwork, mud and straw... built on the outskirts of Lyon (France are presented in a systematic way. The ensemble is called «Le Domaine de la Terre», and eleven different projects are concerned, where a number of institutions and teams of professionals have worked. In its whole it is an excelent exposition at natural scale of the possibilities of mud construction, even though the results are of a great diversity -formal and conceptually- between those diverse projects.Se presentan en el trabajo de forma sistematizada algunas de las realizaciones de viviendas experimentales a base de tierra (bloques, tapial, bloques compactados, tierra-paja.... realizadas en las cercanías de Lyon (Francia y que constituyen el conjunto «Le Domaine de la Terre». Se trata de una realización a base de once proyectos distintos en los que han intervenido un buen número de instituciones, equipos de proyecto y profesionales franceses. Globalmente constituyen una excelente exposición a escala natural de las posibilidades de las construcciones de tierra, aunque los resultados son muy diversos -formal y conceptualmente- entre los distintos proyectos.
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Construction work of superstructure of twin harp bridge. Twin harp kyo jobuko no seko
Energy Technology Data Exchange (ETDEWEB)
Sasaki, H.; Sato, Y.; Kanazawa, Y. (Sumitomo Construction Kajima Corp. Dopy Construction Co. Ltd. Nihon Koatsu Concrete Co. Ltd. Joint Venture, Tokyo (Japan)); Sema, M. (Sumitomo Construction Co. Ltd., Tokyo (Japan))
1991-11-30
Construction plan outline of PC cable stayed bridge with main tower having one pillar structure is introduced and this is the first type of bridge in Japan with three continuous span design. Construction was commenced on 7 July, 1989 and was completed on 8 August, 1991 at south east of Ashahikawa, Hokkaido. Construction outline is consisted of Principal specifications, general layout of structure, construction order and overall stage of the construction work. Main tower is described by its outline, jump system, installation of diagonal member anchorage device, formwork and concrete structure, and cross beam construction has included four parts which are outline, capital part, projected part construction, lateral span and closure part, and central control span and closure part. Outline, cable guard and erection work, cable work, work Procedure of cable taut construction using total taut method, tension adjustment of cable and grouting, for diagonal member are explained. The construction control items specific to cable stayed bridge are diagonal member tension control( control of applied tension, change of tension with time and test taut ) and camber control. Practical vibration test was carried out on March, 1991. 8 refs., 15 figs., 5 tabs.
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AP1000 shield building: a constructability challenge
International Nuclear Information System (INIS)
Di Giuseppe, Giovanni; Bonanno, Domenico
2010-01-01
The AP1000 Shield Building, an enhanced structure which surrounds the containment vessel, consists of standard Reinforced Concrete (RC) and composite Steel and Concrete (SC) construction. In the SC module the surface steel plates, (with attached shear studs and angles) filled with concrete, act as the steel reinforcement in concrete. This is a relatively new design technology that required the appropriate use of structural codes, supplemented with information from applicable tests on similar composite steel and concrete construction. Being a newer design concept, existing codes do not provide explicit guidance on SC construction so a review of literature and test data on composite structures similar to AP1000 shield building was done in order to confirm the technical basis for the design. The SC walls, air inlet structure and roof of the Shield Building will be constructed using modular construction practices and then transported to site and lifted into place. These modules, working also as permanent form-work, will be filled with high strength Self- Consolidating Concrete. (SCC) This paper provides a focused and integrated presentation of the enhanced shield building design methodology, testing, constructability and inspection. (authors)
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Directory of Open Access Journals (Sweden)
Nervi, Pier Luigi
1965-07-01
Full Text Available At the Turin Fiat factory an elevated water tank has been built, with a capacity of 2,000 m3 60 m above the ground, and cup shaped. The structure is reinforced concrete, and prefabricated panels are used, which are supported by a concrete disc, a cylindrical crown and radial ribs. The whole rests on piles. The stem is 8 m in diameter, and has been constructed with the aid of U shaped cylindrical panels, 3 cm in thickness, which served as external formwork for the stem walls. These are 60 cm thick at the bottom, and 50 cm at the top. The tank itself is a paraboloid, made with triangular panels which together form conical circular rings. These also served as formwork, and were supported by a tubular scaffolding. An observation post has been built on top of the tank. It is 25 m in diameter, and is covered with a ribbed spherical cupola, supported by hinged columns, which allow radial deformations, which are not transmitted to the top ring of the tank. The latter, being full of water, is kept at a more uniform temperature than the cupular roof, which is fully exposed to the weather.En la factoría Fiat, de Turín (Italia, se ha construido este depósito elevado, en forma de copa, de 2.000 m3 de capacidad y unos 60 m de altura sobre el suelo. Es de hormigón armado y paneles prefabricados, apoyándose sobre un disco de hormigón, una corona cilíndrica y contrafuertes radiales; todo lo cual descansa sobre pilotes. El fuste, de 8 m de diámetro, se ha construido con la ayuda de una serie de paneles, de superficie cilíndrica y sección transversal en forma de U con alas asimétricas, de 3 cm de espesor, que sirvieron de encofrado exterior en el hormigonado de las paredes, cuyo espesor varía de 60 cm en la zona inferior a 50 cm en la superior. La cubeta es un meridiano parabólico de revolución, constituido por paneles triangulares, formando anillos troncocónicos, que se utilizaron también como encofrado, apoyado sobre un entramado tubular en
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Portland cement hydration and early setting of cement stone intended for efficient paving materials
Grishina, A.
2017-10-01
Due to the growth of load on automotive roads, modern transportation engineering is in need of efficient paving materials. Runways and most advanced highways require Portland cement concretes. This makes important the studies directed to improvement of binders for such concretes. In the present work some peculiarities of the process of Portland cement hydration and early setting of cement stone with barium hydrosilicate sol were examined. It was found that the admixture of said sol leads to a shift in the induction period to later times without significant change in its duration. The admixture of a modifier with nanoscale barium hydrosilicates increases the degree of hydration of the cement clinker minerals and changes the phase composition of the hydration products; in particular, the content of portlandite and tricalcium silicate decreases, while the amount of ettringite increases. Changes in the hydration processes of Portland cement and early setting of cement stone that are caused by the nanoscale barium hydrosilicates, allow to forecast positive technological effects both at the stage of manufacturing and at the stage of operation. In particular, the formwork age can be reduced, turnover of molds can be increased, formation of secondary ettringite and corrosion of the first type can be eliminated.
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Seismic performance for vertical geometric irregularity frame structures
Ismail, R.; Mahmud, N. A.; Ishak, I. S.
2018-04-01
This research highlights the result of vertical geometric irregularity frame structures. The aid of finite element analysis software, LUSAS was used to analyse seismic performance by focusing particularly on type of irregular frame on the differences in height floors and continued in the middle of the building. Malaysia’s building structures were affected once the earthquake took place in the neighbouring country such as Indonesia (Sumatera Island). In Malaysia, concrete is widely used in building construction and limited tension resistance to prevent it. Analysing structural behavior with horizontal and vertical static load is commonly analyses by using the Plane Frame Analysis. The case study of this research is to determine the stress and displacement in the seismic response under this type of irregular frame structures. This study is based on seven-storey building of Clinical Training Centre located in Sungai Buloh, Selayang, Selangor. Since the largest earthquake occurs in Acheh, Indonesia on December 26, 2004, the data was recorded and used in conducting this research. The result of stress and displacement using IMPlus seismic analysis in LUSAS Modeller Software under the seismic response of a formwork frame system states that the building is safe to withstand the ground and in good condition under the variation of seismic performance.
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Accelerated delivery of hydro electrical projects; Livraison acceleree des projets hydroelectriques
Energy Technology Data Exchange (ETDEWEB)
Benjannet, Hassine; Bechard, Normand
2010-09-15
Hydro electrical projects, as other energy projects, must transform in order to adapt to current market demands. This article describes the solutions developed during the construction of the Eastmain-1-A power plant in order to speed up its delivery and to reduce the costs. These solutions include, more comprehensive land investigations, the simplification of excavation contours, the refit or elimination of certain work spaces, the addition of a second access during construction, the simplification of the formworks, the improvement of work zones access and especially the use of prefabricated elements. [French] Les projets hydroelectriques, comme les autres projets energetiques, doivent subir des transformations pour s'adapter aux exigences actuelles du marche. Cet article presente les solutions mises en oeuvre pour la construction de la Centrale de l'Eastmain-1-A en vue d'en accelerer la livraison et d'en reduire le cout. Ces solutions comprennent, entre autres des investigations de terrain plus approfondies, la simplification des contours d'excavations, le reamenagement ou l'elimination de certains locaux, l'addition d'un deuxieme acces pendant la construction, la simplification des coffrages, l'amelioration des acces aux zones de travail et surtout l'utilisation d'elements prefabriques.
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La torre del Danubio, en Viena
Directory of Open Access Journals (Sweden)
Schmidt, Wilhelm
1965-04-01
Full Text Available The symbolic tower of the horticultural exhibition, held recently in Vienna, is a 260 m high structure made of reinforced concrete. Of the total height, 181 m constitute the stem, and the rest is made up of a metallic needle. Inside the tower there are two lifts, each with capacity for 15 people, and a travelling velocity of 6.5 m/sec. In the top 31 ms of the stem there are two terraces, a bar and a restaurant: they provide a wonderful view of the city and the surrounding district. The vertical outline of the stem is an arc of a parabola. A sliding formwork has been utilized for its construction, and a height of 4 m has been concreted every day: this has meant a movement of 25 cm of the formwork every hour. The tower has a weight of 17000 tons, which imposes large loads on the foundation. To withstand these, the foundations have been made in the form of a truncated cone, with a cylindrical hollow core. The base of the cone has an external diameter of 31 m, and an internal diameter of 10.20 m. A compression hoop strengthens the joint between the foundation cone and the stem itself. Although this tower is located in the centre of the city, it harmonizes very well with the surrounding buildings.La torre simbólica de la Exposición de Horticultura, celebrada recientemente en Viena (Austria, es de hormigón armado y tiene 260 m de altura total, de los que 181 corresponden al fuste y el resto a una aguja metálica. En el interior del fuste se han instalado dos ascensores para 15 personas cada uno, con una velocidad de 6,5 m por segundo. En los últimos 31 m se han montado terrazas, un bar y un restaurante, constituyendo las primeras unos magníficos miradores para contemplar la ciudad y sus alrededores- Dicho fuste es de hormigón armado y tiene un perfil en arco de parábola. Su construcción se ha realizado utilizando encofrados deslizantes. Se hormigonó a un ritmo de 4 m por día y una velocidad de corrimientos de los encofrados de 0,25 m por
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Sealing of decant structure at QCM using a tailings cement grout mix
Energy Technology Data Exchange (ETDEWEB)
Bedard, C.; Goulisty, P.; Lemieux, J. [Journeaux, Bedard and Associates Inc., Dorval, PQ (Canada)
2001-10-01
It became necessary for Quebec Cartier Mining (QCM) to transfer the decantation point at the Mont-Wright mine to the Hesse 4 dam and proceed with the permanent sealing of the decant structure at dam A, as a result of the gradual advancement of the tailings mine waste in the Hesse North primary settling basin. A study was conducted to evaluate the use of tailings incorporated in a non-shrink Portland cement grout mix to adequately seal the decant structure of the 30 m high process water earth dam, and the results are presented in this paper. Along with the existing tailings, a type I Portland cement and supplementary cementing materials including fly ash and silica fume were tested. Using a series of design criteria including durability requirements, strength, density, segregation, bleeding, initial and final set, shrinkage, expansion, underwater placement, flowability, pumpability, and others, Journeaux, Bedard and Associates Incorporated completed a series of laboratory tests and trial mixes. Air entrainment admixture, anti-washout admixture, expansion admixture, bentonite, superplasticizer, etc. were tested in the various grout mixes. The design criteria, methodology, laboratory results, various placing techniques, such as pressure grouting, pumping, tremie and others, and formwork used to seal the decant structures are all detailed in the paper. A section is also devoted to the many challenges encountered during the testing. 11 figs.
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Shahidan, Shahiron; Tayeh, Bassam A.; Jamaludin, A. A.; Bahari, N. A. A. S.; Mohd, S. S.; Zuki Ali, N.; Khalid, F. S.
2017-11-01
The development of concrete technology shows a variety of admixtures in concrete to produce special concrete. This includes the production of self-compacting concrete which is able to fill up all spaces, take formwork shapes and pass through congested reinforcement bars without vibrating or needing any external energy. In this study, the main objective is to compare the physical and mechanical properties of self-compacting concrete containing metakaolin with normal concrete. Four types of samples were produced to study the effect of metakaolin towards the physical and mechanical properties of self-compacting concrete where 0%, 5%, 10% and 15% of metakaolin were used as cement replacement. The physical properties were investigated using slump test for normal concrete and slump flow test for self-compacting concrete. The mechanical properties were tested for compressive strength and tensile strength. The findings of this study show that the inclusion of metakaolin as cement replacement can increase both compressive and tensile strength compared to normal concrete. The highest compressive strength was found in self-compacting concrete with 15% metakaolin replacement at 53.3 MPa while self-compacting concrete with 10% metakaolin replacement showed the highest tensile strength at 3.6 MPa. On top of that, the finishing or concrete surface of both cube and cylinder samples made of self-compacting concrete produced a smooth surface with the appearance of less honeycombs compared to normal concrete.
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What are the Dominant Factors of Students’ Productive Skills in Construction Services?
Oroh, R. R.; S, Haris A.; Sugandi, R. M.; Isnandar
2018-02-01
The purpose of this study to determine the dominant factors of students’ productive skills in doing the work of concrete structures that fit the needs of construction services. Sample of the respondents is vocational high school students from several districts and cities in North Sulawesi, Indonesia. Data are obtained through the performance test instruments of student. Whereas, data analysis is performed using factor analysis. The result of this research show the dominant factors of the students’ productive skills in doing the work of concrete structures that is according to the need of construction services, namely: (a) factor the working of concrete casting consists of making scaffolding from good materials and conducting concrete casting according to working method; and (b) factor the working of concrete reinforcing consists of read the working drawings for concrete reinforcement and make the concrete formwork from good material. Some of the respondent’s students in doing some concrete structure work have done well, but not yet according to working drawings, working methods and technical specifications of the work. The learning is done in accordance with the competency-oriented school curriculum but the teaching materials given have not been maximized in accordance with the needs of productive skills required construction services industry. The results have an impact on the low absorption of graduates in the implementation of the construction services industry.
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Peshnina, I.; Sinitsina, O.
2017-11-01
The study relevance is determined by the increasing interest in reconstruction of city historical centers and located in the area of industrial buildings the functional profile of which needs to be changed. The problem of obtaining extra usable spaces in the historical centers of cities is solved by raising the number of storeys in the buildings which can be achieved by the construction of additional built-in inter-floor overlaps. The article is dedicated to the analysis of the recent years’ experience in reconstruction design involving this method in our country and abroad, in the Netherlands, in particular. The article presents the results of the analysis of the experience in reconstruction of the objects by constructing additional inter-floor overlaps and aims to define the optimum construction solution for built-in inter-floor overlapping and to develop non-existing solutions for wide application of this method in the reconstruction of a building with non-unified and unmodulated parameters. It was determined as expedient to apply a monolith reinforced concrete slab with the use of steel profiled flooring as a formwork and reinforcement and steel beams designed as “Built-in Beams” for the construction of built-in inter-floor overlaps in reconstruction. The article will be useful for specialists doing research in the sphere of reconstruction of the buildings and for the practical activity of design engineers.
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Construcción de un anfiteatro subterráneo de mil plazas
Directory of Open Access Journals (Sweden)
Hereng, J. M.
1963-02-01
Full Text Available The Arts and Crafts School of Paris was in need of an auditorium, with accommodation for one thousand persons, suitable for lessons and lectures. Owing to lack of space, it was decided to build it underground, below one of the courtyards. The choice of roof shape was an ellipsoid of revolution, whose major axis is inclined to the horizontal. The maximum diameter is 32 ms and maximum height is 10 ms. The thickness of the roof structure is 50 cms along the lower part, and 20 cms near the crown. This solution was of special interest as it overcame simultaneously two difficulties; namely, the foundation, when this has to be based on fill soil, and the non-interference with the illumination of nearby buildings. In this case the loading on the soil is always less than 380 grams per cm-, even assuming a local settlement of the soil over any area of 20 ms in diameter. Concrete has been transported to the required sites by means of compressed air chutes, with the result that the rate of concreting has not been interfered with. Formwork has been carefully thought out, especially over the zones where the floor surface changes into the auditorium vault. The tubular structure supporting the formwork of the vault has been erected with columns which are normal to the inclined diametral plane of the surface of revolution. Owing to this unusual arrangement, the staff working at the site have often lost their sense of balance.El Conservatorio de Artes y Oficios de París necesitaba un anfiteatro capaz para mil plazas, utilizable para clases y conferencias. Por falta de espacio se decidió construirlo subterráneo en uno de los patios. La solución adoptada fue la de un elipsoide de revolución de eje mayor inclinado respecto de la horizontal con 32 m de diámetro y 10 de altura máxima; el espesor en la parte inferior es de 50 cm y en la superior de 20 centímetros. Esta solución es de particular interés, ya que solventaba de una vez dos problemas: el de
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Directory of Open Access Journals (Sweden)
Wittfoht, Hans
1965-02-01
Full Text Available A bypass on the general highway is now being built near Andernach, Germany. It is about 1100 m long, and includes an elevated way. The design has been influenced by the poor soil resistance, and the fact that the road is built on a mountainside. The elevated way runs along a curve, with a minimum radius of 475 m, and is subdivided into 34 sections, each 31.75 m long. The deck consists of a box girder, separated into two compartments, and is of prestressed concrete. The deck cantilevers on each side of the longitudinal structure, and has a total width of 18.20 m. This allows for two separate pavements, a central separating section, and two lateral sidewalks. The construction procedure was significant. Owing to the nature of soil, and the need to avoid heavy concentrated loads, the traditional system of formwork was substituted by the Gerber procedure. This consists of 4 metal open girders which rest on the columns, which had been previously constructed. These beams, which are capable of conforming to the curvature of the road, are moved along the axis of the deck, with the aid of hydraulic jacks, as the process of concreting proceeds. A crane, with an operational reach of 35 m served to supply the materials and formwork at the various construction points.En las proximidades de Andernach (Alemania se está construyendo una derivación de la carretera general, con unos 1.100 m de longitud total, que consiste en una especie de puente o paso elevado. Se justifica esta solución particular por la poca consistencia del terreno y el especial trazado a media ladera. El eje del paso elevado sigue una alineación curva con radio mínimo de 475 m, y está subdividido en 34 tramos de 31,75 m de luz. El conjunto que forma el tablero es una viga cajón, bicelular, de hormigón pretensado y grandes salas en voladizo que dan una anchura total de 18,20 m, lo cual permite la habilitación de dos bandas de circulación separadas por un macizo central y dos andenes
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Directory of Open Access Journals (Sweden)
Beltramone, A.
2003-06-01
Full Text Available The actual research study, carried out in the Laboratory of Construction Materials of the ETSAM., analyses the modifications in superficial properties (regarding colour and texture of grey Portland cement mortars due to the use of different formworks release agents (car oil, mineral oil and paraffin and to the addition of plastic superplasticiser to the mixture (Bettor and Sika trademarks. Once the test samples were obtained, a digital registration was made by giving them values in terms of colour and texture observed changes using computer programmes, referring those values to the test specimen (only cement, no additives. A migration of the polymeric particles of the additives towards the surface was observed, presenting the following modifications: Colour: darker hues than those of the test specimen sample were registered in the specimens with additives. Texture: the texture of the test specimen containing additives such as modified polycarboxilic ethers, polycarboxilic ethers; modified organic polymers and modified synthetic melamine were much smoother than the one in test specimen. Test specimens containing melamine, condensed naftalensulphate and polycarboxilic derivatives were a bit rougher but still smoother than the test specimen. The same variation of results as for the colour properties was obtained for the texture as regards to the use of formworks release agents, varying from smoothest to roughest with the car oil.
El presente estudio experimental, realizado en las instalaciones del Laboratorio de Materiales de Construcción de la ETSAM, analiza las modificaciones de las propiedades superficiales observadas (en cuanto a color y textura en morteros de cemento portland gris, por la utilización de desencofrantes diversos (aceite de automóvil, aceite mineral y desencofrante parafínico, y la incorporación de aditivos superfluidificantes plásticos en la mezcla (de las marcas Bettor y Sika. Una vez obtenidas las diferentes -
Ma, Guowei; Zhang, Junfei; Wang, Li; Li, Zhijian; Sun, Junbo
2018-07-01
3D concrete printing is an innovative and promising construction method that is rapidly gaining ground in recent years. This technique extrudes premixed concrete materials through a nozzle to build structural components layer upon layer without formworks. The build-up process of depositing filaments or layers intrinsically produce laminated structures and create weak joints between adjacent layers. It is of great significance to clearly elaborate the mechanical characteristics of 3D printed components response to various applied loads and the different performance from the mould-cast ones. In this study, a self-developed 3D printing system was invented and applied to fabricate concrete samples. Three points bending test and direct double shear test were carried out to investigate the mechanical properties of 3D printed prisms. The anisotropic behaviors were probed by loading in different directions. Meanwhile, piezoelectric lead zirconate titanate (PZT) transducers were implemented to monitor the damage evolution of the printed samples in the loading process based on the electromechanical impedance method. Test results demonstrate that the tensile stresses perpendicular to the weaken interfaces formed between filaments were prone to induce cracks than those parallel to the interfaces. The damages of concrete materials resulted in the decrease in the frequency and a change in the amplitude in the conductance spectrum acquired by mounted PZT patches. The admittance signatures showed a clear gradation of the examined damage levels of printed prisms exposed to applied loadings.
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Estudio sobre encofrados de madera modernos
Directory of Open Access Journals (Sweden)
de la Peña Aznar, Juan M.
1980-11-01
Full Text Available The author continues the development of the subject «Modern Timber Formwork», by summing up the comparative examination —already carried out in Part III of this Study— of the different types of glued timber existing on the market. In addition, the loads and stresses allowable for coniferous timber and the proposal for establishing Regulations for the Timber Section of the Research and Experimental Forestry Institute of Spain are given. In part V of the author's Study, published in this article, the important subject of the glues used for joining timber, a truly vital point in order to obtain louvered timber beams which are simply glued together, is approached.
El autor continúa el desarrollo del tema sobre «Encofrados de madera modernos», resumiendo el estudio comparativo —ya hecho en la Parte III de este Estudio— de las diferentes vigas de madera encolada existentes en el mercado dando, además, las cargas y tensiones admisibles para maderas coníferas y la propuesta de Reglamentación de la Sección de Maderas del Instituto Forestal de Investigaciones y Experiencias de España. En la parte V del Estudio del autor, publicada en este articulo, se aborda el importante tema de las colas empleadas para las uniones de madera, algo realmente vital para la obtención de vigas de madera en celosía simplemente encoladas. -
Gikas, Vassilis
2012-01-01
Driven by progress in sensor technology, computer software and data processing capabilities, terrestrial laser scanning has recently proved a revolutionary technique for high accuracy, 3D mapping and documentation of physical scenarios and man-made structures. Particularly, this is of great importance in the underground space and tunnel construction environment as surveying engineering operations have a great impact on both technical and economic aspects of a project. This paper discusses the use and explores the potential of laser scanning technology to accurately track excavation and construction activities of highway tunnels. It provides a detailed overview of the static laser scanning method, its principles of operation and applications for tunnel construction operations. Also, it discusses the planning, execution, data processing and analysis phases of laser scanning activities, with emphasis given on geo-referencing, mesh model generation and cross-section extraction. Specific case studies are considered based on two construction sites in Greece. Particularly, the potential of the method is examined for checking the tunnel profile, producing volume computations and validating the smoothness/thickness of shotcrete layers at an excavation stage and during the completion of excavation support and primary lining. An additional example of the use of the method in the geometric documentation of the concrete lining formwork is examined and comparisons against dimensional tolerances are examined. Experimental comparisons and analyses of the laser scanning method against conventional surveying techniques are also considered. PMID:23112655
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Verificación de las propiedades reológicas del hormigón sin vibrado
Directory of Open Access Journals (Sweden)
Gallo, E.
2004-04-01
Full Text Available The process of casting is a key issue in the final properties of concrete. The struggle to improve this process has brought the development of a new type of concrete that does not require external vibration in order to fill the formwork. This new type of concrete, known as selfcompacting concrete, differs from other concretes in its rheological properties, but the existing concrete tests does not provide enough information to fully characterize this concrete, either during the design process or the reception at the work place. This work studies some of the proposed validation tests for the fresh state, distinguishing som e advantages and drawbacks among them.
El proceso de puesta en obra constituye un aspecto clave en las propiedades finales del hormigón. La mejora de este proceso ha desembocado en la aparición de nuevos tipos de hormigón en los que no se necesita vibrado mediante medios mecánicos para rellenar los encofrados. Este tipo de hormigón, conocido como autocompactable, se distingue de otros hormigones por sus propiedades reológicas; pero los actuales ensayos de verificación de las propiedades del hormigón resultan insuficientes para la caracterización completa del hormigón sin vibrado en estado fresco. Este trabajo estudia algunos de los métodos de valoración de propiedades en estado fresco, llegando a distinguir ventajas e inconvenientes de dichos métodos. -
Chen, Xudong; Xi, Fengming; Geng, Yong; Fujita, Tsuyoshi
2011-01-01
With the increasing attention on developing a low-carbon economy, it is necessary to seek appropriate ways on reducing greenhouse gas (GHG) emissions through innovative municipal solid waste management (MSWM), such as urban symbiosis. However, quantitative assessments on the environmental benefits of urban symbiosis, especially in developing countries, are limited because only a limited number of planned synergistic activities have been successful and it is difficult to acquire detailed inventory data from private companies. This paper modifies and applies a two-step simulation system and used it to assess the potential environmental benefits, including the reduction of GHG emissions and saving of fossil fuels, by employing various Japanese plastics recycling/energy-recovery technologies in Shenyang, China. The results showed that among various recycling/energy-recovery technologies, the mechanical waste plastics recycling technology, which produces concrete formwork boards (NF boards), has the greatest potential in terms of reducing GHG emissions (1.66 kg CO(2)e/kg plastics), whereas the technology for the production of refuse plastic fuel (RPF) has the greatest potential on saving fossil fuel consumption (0.77 kg ce/kg-plastics). Additional benefits can be gained by applying combined technologies that cascade the utilization of waste plastics. Moreover, the development of clean energy in conjunction with the promotion of new waste plastics recycling programs could contribute to additional reductions in GHG emissions and fossil fuel consumption. Copyright © 2010 Elsevier Ltd. All rights reserved.
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Estudio sobre encofrados de madera modernos
Directory of Open Access Journals (Sweden)
de la Peña Aznar, Juan M.
1980-12-01
Full Text Available The author continues the development of the subject «Modern Timber Formwork», by summing up the comparative examination —already carried out in Part III of this Study— of the different types of glued timber existing on the market. In addition, the loads and stresses allovk/able for coniferous timber and the proposal for establishing Regulations for the Timber Section of the Research and Experimental Forestry Institute of Spain are given. In part V of the author's Study, published in this article, the important subject of the glues used for joining timber, a truly vital point in order to obtain louvered timber beams which are simply glued together, is approached.
El autor continúa el desarrollo del tema sobre «Encofrados de madera modernos», resumiendo el estudio comparativo —ya hecho en la Parte III de este Estudio— de las diferentes vigas de madera encolada existentes en el mercado dando, además, las cargas y tensiones admisibles para maderas coníferas y la propuesta de Reglamentación de la Sección de Maderas del Instituto Forestal de Investigaciones y Experiencias de España. En la parte V del Estudio del autor, publicada en este artículo, se aborda el importante tema de las colas empleadas para las uniones de madera, algo realmente vital para la obtención de vigas de madera en celosía simplemente encoladas. -
Seismic Rehabilitation of RC Frames by Using Steel Panels
Mowrtage, Waiel
2008-07-01
Every major earthquake in Turkey causes a large number of building suffer moderate damage due to poor construction. If a proper and fast retrofit is not applied, the aftershocks, which may sometimes come days or weeks after the main shock, can push a moderately damaged building into a major damage or even total collapse. This paper presents a practical retrofit method for moderately damaged buildings, which increases the seismic performance of the structural system by reducing the displacement demand. Fabricated steel panels are used for the retrofit. They are light-weight, easy to handle, and can be constructed very quickly. Moreover, they are cheap, and do not need formwork or skilled workers. They can be designed to compensate for the stiffness and strength degradation, and to fit easily inside a moderately damaged reinforced concrete frame. To test the concept, a half-scale, single-story 3D reinforced concrete frame specimen was constructed at the shake-table laboratories of the Kandilli Observatory and Earthquake Research Institute of Bogazici University, and subjected to recorded real earthquake base accelerations. The amplitudes of base accelerations were increased until a moderate damage level is reached. Then, the damaged RC frames was retrofitted by means of steel panels and tested under the same earthquake. The seismic performance of the specimen before and after the retrofit was evaluated using FEMA356 standards, and the results were compared in terms of stiffness, strength, and deformability. The results have confirmed effectiveness of the proposed retrofit scheme.
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Seismic Rehabilitation of RC Frames by Using Steel Panels
International Nuclear Information System (INIS)
Mowrtage, Waiel
2008-01-01
Every major earthquake in Turkey causes a large number of building suffer moderate damage due to poor construction. If a proper and fast retrofit is not applied, the aftershocks, which may sometimes come days or weeks after the main shock, can push a moderately damaged building into a major damage or even total collapse. This paper presents a practical retrofit method for moderately damaged buildings, which increases the seismic performance of the structural system by reducing the displacement demand. Fabricated steel panels are used for the retrofit. They are light-weight, easy to handle, and can be constructed very quickly. Moreover, they are cheap, and do not need formwork or skilled workers. They can be designed to compensate for the stiffness and strength degradation, and to fit easily inside a moderately damaged reinforced concrete frame.To test the concept, a half-scale, single-story 3D reinforced concrete frame specimen was constructed at the shake-table laboratories of the Kandilli Observatory and Earthquake Research Institute of Bogazici University, and subjected to recorded real earthquake base accelerations. The amplitudes of base accelerations were increased until a moderate damage level is reached. Then, the damaged RC frames was retrofitted by means of steel panels and tested under the same earthquake. The seismic performance of the specimen before and after the retrofit was evaluated using FEMA356 standards, and the results were compared in terms of stiffness, strength, and deformability. The results have confirmed effectiveness of the proposed retrofit scheme
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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
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RCC-CW - Rules for design and construction of PWR nuclear civil works
International Nuclear Information System (INIS)
2016-01-01
RCC-CW describes the rules for designing, building and testing civil engineering works in PWR reactors. It explains the principles and requirements for the safety, serviceability and durability of concrete and metal frame structures, based on Eurocode design principles (European standards for the structural design of construction works) combined with specific measures for safety-class buildings. The code is produced as part of the RCC-CW Subcommittee, which includes all the parties involved in civil engineering works in the nuclear sector: clients, contractors, general and specialized firms, consultancies and inspection offices. The code covers the following areas relating to the design and construction of civil engineering works that play an important safety role: geotechnical aspects, reinforced concrete structures and galleries, pre-stressed containments with metal liner, metal containment and pool liners, metal frames, anchors, concrete cylinder pipes, containment leak tests. The RCC-CW code is available as an ETC-C version specific to EPR projects (European pressurized reactor). Contents of the 2016 edition of the RCC-CW Code: Part G - General: scope, standards, notations, quality management, general principles; Part D - Design: actions and combinations of actions, geotechnical aspects, pre-stressed or reinforced concrete structures, metal containment liners, metal pool liners, metal frames, anchors; Part C - Construction: geotechnical aspects, concrete, surface finish and formwork, reinforcement for reinforced concrete, pre-stressing processes, prefabricated concrete elements, metal containment liners, metal pool liners, metal frames, anchors, embedded pipelines, joint sealing, survey networks and tolerances; Part M - Maintenance and monitoring: containment integrity and rate tests
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Karolina, R.; Muhammad, W.; Saragih, M. D. S. M.; Mustaqa, T.
2018-02-01
Self Compacting Concrete is a concrete variant that has a high degree of workability and also has great initial strength, but low water cement factor. It is also self-flowable that can be molded on formwork with a very little or no compacted use of compactors. This concrete, using a variety of aggregate sizes, aggregate portions and superplasticizer admixture to achieve a special viscosity that allows it to flow on its own without the aid of a compactor. Lightweight concrete brick is a type of brick made from cement, sand, water, and developers. Lightweight concrete bricks are divided into 2 based on the developed materials used are AAC (Autoclave Aerated Concrete) using aluminum paste and CLC (Cellular Lightweight Concrete) that use Foaming Agent from BASF as a developer material. In this experiment, the lightweight bricks that will be made are CLC type which uses Foaming Agent as the developer material by mixing the Ash Stone produced by Stone Crusher machine which has the density of 2666 kg / m3 as Partial Pair Substitution. In this study the variation of Ash Stone used is 10%, 15%, and 20% of the planned amount of sand. After doing the tasting the result is obtained for 10% variation. Compressive Strength and Absorption Increase will decrease by 25.07% and 39.005% and Variation of 15% compressive strength will decrease by 65,8% and decrease of absorbtion equal to 17,441% and variation of 20% compressive strength will decreased by 67,4 and absorption increase equal to 17,956%.
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Design development of steel plate concrete modularization for the advanced PWR in Korea
International Nuclear Information System (INIS)
Mun, Taeyoup; Kim, Keunkyeong; Sun, Wonsang; Kim, Taeyoung; Hwang, Geunha
2008-01-01
APR1400 TM - an advanced PWR - has been developed in Korea since 1992. Four APR1400 units - Shin Kori no.3,4 and Shin Uljin no.1,2 - are going to be built in a next decade. As for economical efficiency, construction cost per power generation Unit(W) is improved more than 10% compared to the former 1,000 MWe PWRs. Moreover, life-cycle maintenance cost is reduced to the world's most level. For construction period from first concrete pouring to commercial operation, 54 months for APR1400 and 36 months for n-th unit have been projected. Reduction of the construction term of the Nuclear Power Plant has been emphasized increasingly for the NPP construction Project because it would reduce the interest cost and uncertainty of the project. The reduction can also advance the return of investment. Some of the PPM(Prefabrication, Preassembly, and Modularization) techniques have been studied for the shortening the construction period of nuclear power plant. Especially for the internal structure of reactor containment building (RCB) in PWR whose term of construction is critical to the whole project, Steel Plate Concrete(SC) structure has been studied as one of alternative structural systems to the conventional Reinforced Concrete(RC) structure in APR1400. SC structure is considered appropriate for the modularization of the structure with its self-supporting. In addition, formwork can be dramatically eliminated when SC structural modules are used. The MKE (Ministry of Knowledge Economy) and KHNP (Korea Hydro and Nuclear Power Co., Ltd.) initiated the research and development of SC Structure in 2005. This paper presents design examples along with Codes and Standards of SC structure in nuclear power plant. (author)
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Directory of Open Access Journals (Sweden)
Población Knappe, Eleuterio
1981-03-01
Full Text Available This article describes the building of the world's longest single- span hanging bridge (2,250 metres in the Humber estuary. The floor of this bridge, the main light of which Is 1,410 m, is formed by trapezoidal chestbeams made with 18 m long rigid sheets. This makes possible both economy of steel and a reduction In the dimensions of the cables, pylons and anchorage masses. The pylons, built of sliding formwork, consist of two 155 m high reinforced concrete hollow pillars.These pillars are joined by four horizontal struts. The construction of the Humber bridge allows the distances between both shores of the estuary to be cut and completes the motorway network in the area.
Se describe en este artículo la construcción del puente colgado de tramo sencillo más largo del mundo (2.250 m en el estuario de Humber. El tablero de este puente, cuya luz principal es de 1.410 m, está formado por vigas-cajón trapezoidales realizadas mediante chapas rigidizadas de 18 m de longitud. De esta manera se obtiene una economía de acero así como una reducción en las dimensiones de los cables, pilonos y macizos de anclaje. Los pilonos, construidos con encofrado deslizante, se componen de dos pilares huecos de hormigón armado de 155 m de altura. Estos pilares están unidos por cuatro riostras horizontales. La construcción del puente de Humber permite acortar las distancias entre ambas orillas del estuario y completa la red de autopistas de la zona. -
Van Tang, Lam; Bulgakov, Boris; Bazhenova, Sofia; Aleksandrova, Olga; Pham, Anh Ngoc; Dinh Vu, Tho
2018-03-01
The dense development of high-rise construction in urban areas requires a creation of new concretes with essential properties and innovative technologies for preparing concrete mixtures. Besides, it is necessary to develop new ways of presenting concrete mixture and keeping their mobility. This research uses the mathematical method of two-factors rotatable central compositional planning to imitate the effect of amount of rice husk (RHA) and fly ash of thermal power plants (FA) on the workability of high-mobility concrete mixtures. The results of this study displays regression equation of the second order dependence of the objective functions - slump cone and loss of concrete mixture mobility due to the input factors - the amounts RHA (x1) and FA (x2), as well as the surface expression image of these regression equations. An analysis of the regression equations also shows that the amount of RHA and FA had a significant influence on the concrete mixtures mobility. In fact, the particles of RHA and FA will play the role as peculiar "sliding bearings" between the grains of cement leading to the dispersion of cement in the concrete mixture. Therefore, it is possible to regulate the concrete mixture mobility when transporting fresh concrete to the formwork during the high-rise buildings construction in the hot and humid climate of Vietnam. Although the average value of slump test of freshly mixed concrete, measured 60 minutes later after the mixing completion, decreased from 18.2 to 10.52 cm, this value still remained within the allowable range to maintain the mixing and and the delivery of concrete mixture by pumping.
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Advanced construction methods in ACR
International Nuclear Information System (INIS)
Elgohary, M.; Choy, E.; Yu, S.K.W.
2002-01-01
The ACR - Advanced CANDU Reactor, developed by Atomic Energy of Canada Limited (AECL), is designed with constructability considerations as a major requirement during all project phases from the concept design stage to the detail design stage. This necessitated a much more comprehensive approach in including constructability considerations in the design to ensure that the construction duration is met. For the ACR-700, a project schedule of 48 months has been developed for the nth replicated unit with a 36 month construction period duration from First Concrete to Fuel Load. An overall construction strategy that builds on the success of the construction methods that are proven in the construction of the Qinshan CANDU 6 project has been developed for the ACR. The overall construction strategy comprises the 'Open Top' construction technique using a Very Heavy Lift crane, parallel construction activities, with extensive modularization and prefabrication. In addition, significant applications of up to date construction technology will be implemented, e.g. large volume concrete pours, prefabricated rebar, use of climbing forms, composite structures, prefabricated permanent formwork, automatic welding, and utilization of the latest electronic technology tools such as 3D CADDs modelling yields a very high quality, clash free product to allow construction to be completed 'right the first time' and eliminates rework. Integration of 3D CADDs models and scheduling tools such as Primavera has allowed development of actual construction sequences and an iterative approach to schedule verification and improvement. Modularization and prefabrication are major features of the ACR design in order to achieve the project schedule. For the reactor building approximately 80% of the volume will be installed as modules or prefabricated assembles. This ensures critical path activities are achieved. This paper examines the advanced construction methods implemented in the design in order to
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Directory of Open Access Journals (Sweden)
Skanska Cementgjüteriet, Empresa
1974-06-01
Full Text Available The Öland bridge spans across the Kalmar strait, reaching from Möllstorpslage, on the island of Öland, to the island of N. Skallö; from here to the island of Svinö and then to Jutnabben, on the Swedish peninsula. It has 155 spans out of which 147 are small spans, two medium and six central, each one of them 130 m, with a total length of 6.070 m. The high arches have been constructed by the system of successive corbels and the low ones with a launching of big beams of reinforced concrete. Foundations on columns or poured on site in pneumatic emptied boxes, depending on the cases and piers of reinforced concrete, constructed by means of sliding formwork. The Construction Firm has been Skanska Cementgjuteriet, on account of the Government Administration.El puente de Öland salva el estrecho de Kalmar, partiendo de Möllstorpslage, en la isla de Öland, hasta la isla de N. Skallö; de aquí a la de Svinö y desde ésta hasta Jutnabben, en la península sueca. Tiene 155 vanos: 147 de luces pequeñas, 2 de luces medianas y 6 centrales, de 130 m cada una, con una longitud total de 6.070 m. Los arcos denominados altos se han realizado por el sistema de voladizos sucesivos, y los bajos, mediante lanzamiento de grandes vigas de hormigón armado. Cimientos sobre pilotes o vertidos in situ, en cajones vaciados neumáticamente, según los casos, y pilas de hormigón armado, construidas con auxilio de encofrados deslizantes. La Empresa constructora ha sido Skanska Cementgjuteriet, por cuenta de la Administración del Estado.
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International Nuclear Information System (INIS)
Chen Xudong; Xi Fengming; Geng Yong; Fujita, Tsuyoshi
2011-01-01
Research highlights: → Urban symbiosis creates compatibility of industrial development and waste management. → Mechanical technology leads to more CO 2 emission reduction. → Energy recovery technology leads to more fossil fuel saving. → Clean energy makes recycling technologies cleaner. → Demand management is crucial for realizing potential environmental gains of recycling. - Abstract: With the increasing attention on developing a low-carbon economy, it is necessary to seek appropriate ways on reducing greenhouse gas (GHG) emissions through innovative municipal solid waste management (MSWM), such as urban symbiosis. However, quantitative assessments on the environmental benefits of urban symbiosis, especially in developing countries, are limited because only a limited number of planned synergistic activities have been successful and it is difficult to acquire detailed inventory data from private companies. This paper modifies and applies a two-step simulation system and used it to assess the potential environmental benefits, including the reduction of GHG emissions and saving of fossil fuels, by employing various Japanese plastics recycling/energy-recovery technologies in Shenyang, China. The results showed that among various recycling/energy-recovery technologies, the mechanical waste plastics recycling technology, which produces concrete formwork boards (NF boards), has the greatest potential in terms of reducing GHG emissions (1.66 kg CO 2 e/kg plastics), whereas the technology for the production of refuse plastic fuel (RPF) has the greatest potential on saving fossil fuel consumption (0.77 kgce/kg-plastics). Additional benefits can be gained by applying combined technologies that cascade the utilization of waste plastics. Moreover, the development of clean energy in conjunction with the promotion of new waste plastics recycling programs could contribute to additional reductions in GHG emissions and fossil fuel consumption.
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Adoption of Building Information Modelling in project planning risk management
Mering, M. M.; Aminudin, E.; Chai, C. S.; Zakaria, R.; Tan, C. S.; Lee, Y. Y.; Redzuan, A. A.
2017-11-01
An efficient and effective risk management required a systematic and proper methodology besides knowledge and experience. However, if the risk management is not discussed from the starting of the project, this duty is notably complicated and no longer efficient. This paper presents the adoption of Building Information Modelling (BIM) in project planning risk management. The objectives is to identify the traditional risk management practices and its function, besides, determine the best function of BIM in risk management and investigating the efficiency of adopting BIM-based risk management during the project planning phase. In order to obtain data, a quantitative approach is adopted in this research. Based on data analysis, the lack of compliance with project requirements and failure to recognise risk and develop responses to opportunity are the risks occurred when traditional risk management is implemented. When using BIM in project planning, it works as the tracking of cost control and cash flow give impact on the project cycle to be completed on time. 5D cost estimation or cash flow modeling benefit risk management in planning, controlling and managing budget and cost reasonably. There were two factors that mostly benefit a BIM-based technology which were formwork plan with integrated fall plan and design for safety model check. By adopting risk management, potential risks linked with a project and acknowledging to those risks can be identified to reduce them to an acceptable extent. This means recognizing potential risks and avoiding threat by reducing their negative effects. The BIM-based risk management can enhance the planning process of construction projects. It benefits the construction players in various aspects. It is important to know the application of BIM-based risk management as it can be a lesson learnt to others to implement BIM and increase the quality of the project.
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Directory of Open Access Journals (Sweden)
José Benedito Donadon Leal
2018-04-01
Full Text Available Na apresentação das aldravias, em dezembro 2010, os poetas aldravistas anunciaram que as aldravias não seriam fôrmas, inscritas apenas numa proposição sintética de seis versos univocabulares, mas formas abertas às mais diversas experiências poéticas que tenham como prioritária a palavra. Ficava claro que não anunciávamos unicamente um novo tipo de “poema”, mas propúnhamos uma nova “poesia” que expressasse a atualidade de qualquer tempo (aquela da pragmática sensação do presente eterno, em que a atitude própria da construção das metonímias faz emergir a força da palavra do meio do caldo visual que, nesta atualidade, inunda os meios de comunicação e, reiteradamente, cobra a veiculação das ideias através do que esta segunda década do XXI acostumou a chamar de novas narrativas. Palavras-chave: Literatura brasileira, poesia contemporânea, aldravia. ------------------------------------------------- In "Presenting aldravias", in December 2010, aldravistas poets announced that aldravias would not formwork, listed only a synthetic proposition six univocabulares verses, but forms open to various poetic experiences that have the word as a priority. It was clear that we were not announcing a new type of "poem", but we proposing a new "poetry" to express the relevance of any time (that of the pragmatic sense of the eternal present, in which the very attitude of the construction of metonymy brings out the strength of the middle word of the visual broth that at this present time, flooding the media, and repeatedly charges the placement of ideas through this second decade of the XXI century accustomed to call new narratives. Keywords: Brazilian literature, contemporary poetry, aldravia.
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Recognition of a heritage in danger: rammed-earth architecture in Lyon city, France
Alex, Dorothée
2018-04-01
Historically, man has built with what he had underfoot: if the earthen construction is a tradition of 11 000 years old, the technique of the rammed earth (earth rammed in a formwork) is relatively new since it appeared for the first time in Tunisia in 814 BC. Exported in France, rammed earth is established mainly in Rhône-Alpes Region which has an ideal soil, rich in gravel, sand, silt and clay. Traditionally associated with the rural world, rammed earth heritage is also present in urban centers. The city of Lyon is one of the rare European cities to concentrate a large proportion of rammed earth buildings: the inventories made show that they are present in almost all the districts as well as in the suburban areas. This high density could be explained by the phenomenon of rural exodus experienced by Lyon during the nineteenth century. The agricultural populations, attracted by the prosperity of the city, then settled at the doors of this city, bringing their know-how by building with the cheaper and easier material available: earth. Rammed earth buildings are therefore located on bounder areas between the countryside and the city. They are thus found on lands that were once outside the city walls. With the advent of the industrial era at the end of the 19th century and the appearance of concrete, rammed earth constructions gradually disappeared. The constructions that we see today are therefore prior to 1900. Varied, ranging from detached houses to the 6-storey buildings, they stand as a testimony to a know-how that finds a particular resonance today, while the environmental and economic concerns are at the forefront. Little known, they constitute a heritage in danger that should be rediscovered.
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Nueva terminal del aeropuerto de Glasgow (Abbotsinch, Inglaterra
Directory of Open Access Journals (Sweden)
Spence, Basil
1968-12-01
Full Text Available This airport substitutes the one at Renfrew, which had become inadequate for the modern volume of traffic. The new airport will handle the intense passenger traffic on the Glasgow London route, which by 1970 it is estimated will reach 970 passengers per hour. Arrangements have been made for a possible enlargement to double the present air traffic capacity of the airport, namely, a maximum of 32 aircraft per hour. The airport building houses everything related to the passengers and offices in the top part, and it has highly modern installations of all types, of which the following are outstanding: the electronic information desks, the bar which is fully air conditioned, and the hall. The general structure is of reinforced concrete, with precast flooring frameworks. The baggage hall has metallic loading tables. The building has a highly impressive external appearance, and is faced with slabs of concrete, whose fine texture has been the result of using carefully chosen formwork of specially grained timber. White slabs and dark brick have also been utilised.Se hizo en sustitución del de Renfrew, que había quedado inadecuado, y dirigirá el intenso movimiento de viajeros y transporte de la ruta Glasgow-Londres, que se calcula, para 1970, en 970 pasajeros a la hora. Por ello, se ha previsto una posible ampliación al doble, con capacidad para un máximo de 33 aviones. El edificio alberga todo lo relacionado con los pasajeros y las oficinas en la parte superior, disponiendo de modernísimas instalaciones de todo tipo, entre las que destacan: los tableros electrónicos y puestos de información, bar y restaurante con climatización total, etc. La estructura general es de hormigón armado con forjados prefabricados; en los muelles es metálica. El aspecto exterior, de una gran elegancia, está conseguido a base de placas de hormigón visto —con bella textura lograda con encofrados muy cuidados de madera rayada—, plaquetas prefabricadas blancas y
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Effect of Silica Fume on two-stage Concrete Strength
Abdelgader, H. S.; El-Baden, A. S.
2015-11-01
Two-stage concrete (TSC) is an innovative concrete that does not require vibration for placing and compaction. TSC is a simple concept; it is made using the same basic constituents as traditional concrete: cement, coarse aggregate, sand and water as well as mineral and chemical admixtures. As its name suggests, it is produced through a two-stage process. Firstly washed coarse aggregate is placed into the formwork in-situ. Later a specifically designed self compacting grout is introduced into the form from the lowest point under gravity pressure to fill the voids, cementing the aggregate into a monolith. The hardened concrete is dense, homogeneous and has in general improved engineering properties and durability. This paper presents the results from a research work attempt to study the effect of silica fume (SF) and superplasticizers admixtures (SP) on compressive and tensile strength of TSC using various combinations of water to cement ratio (w/c) and cement to sand ratio (c/s). Thirty six concrete mixes with different grout constituents were tested. From each mix twenty four standard cylinder samples of size (150mm×300mm) of concrete containing crushed aggregate were produced. The tested samples were made from combinations of w/c equal to: 0.45, 0.55 and 0.85, and three c/s of values: 0.5, 1 and 1.5. Silica fume was added at a dosage of 6% of weight of cement, while superplasticizer was added at a dosage of 2% of cement weight. Results indicated that both tensile and compressive strength of TSC can be statistically derived as a function of w/c and c/s with good correlation coefficients. The basic principle of traditional concrete, which says that an increase in water/cement ratio will lead to a reduction in compressive strength, was shown to hold true for TSC specimens tested. Using a combination of both silica fume and superplasticisers caused a significant increase in strength relative to control mixes.
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Dumoulin, Cédric; Deraemaeker, Arnaud
2018-03-01
Ultrasonic measurements of concrete can provide crucial information about its state of health. The most common practice in the construction industry consists in using external probes which strongly limits the use of the method since large parts of the in-service structures are difficult to access. It is also possible to assess in real time the setting process of the concrete using ultrasonic measurements. In practice, the field measurement of the concrete hardening is limited by the formworks. As an alternative, some research teams have studied the possibility to directly embed the transducers into the concrete structures. The current embedded ultrasonic transducers are of two categories: bulk piezoelectric elements surrounded by several coating and matching layers and composites piezoelectric elements. Both technologies aim at optimizing the wave energy transmitted to the tested medium. The performances of the transducers of the first kind have been studied in a previous study. A fair amount of recent research has been focused on the development of novel cement-based piezoelectric composites. In this study, we first compare the effective properties of such cement-based materials with more widespread composites made with matrices of epoxy resins or polyurethane. The study only concerns the 1-3 fiber arrangement composites. The effective properties are computed using both an analytical mixing rule method and a finite element based homogenization method using representative volume elements (RVEs) which allows for considering more realistic fiber arrangements, leading yet to very similar results. The effective piezoelectric properties of cement-based composites appear to be very low compared to composites made of epoxy or polyurethane. This result is underlined by looking at the acoustic response and the electric input impedance of different piezoelectric disks where we compare performances of such transducers with a low-cost bulk piezoelectric disc element. The first
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Directory of Open Access Journals (Sweden)
Tatjana N. Zhilnikova
2017-01-01
Full Text Available Abstract. Objectives Concretes for injection with a two-stage expansion are a kind of selfstressing concrete obtained with the use of self-stressing cement.The aim of the work is to study the influence of the duration of aging on the porosity, strength and self-stress of concrete hardening in water, depending on the expansion value at the first stage. At the first stage, the compacted concrete mixture is expanded to ensure complete filling of the formwork space. At the second stage, the hardening concrete expands due to the formation of an increased amount of ettringite. This process is prolonged in time, with the amount of self-stress and strength dependant on the conditions of hardening. Methods Experimental evaluation of self-stress, strength and porosity of concretes that are permanently hardened in water, under air-moist and air-dry conditions after different expansion at the first stage. The self-stress of cement stone is the result of superposition of two processes: the hardening of the structure due to hydration of silicates and its expansion as a result of hydration of calcium aluminates with the subsequent formation of ettringite. The magnitude of self-stress is determined by the ratio of these two processes. The self-stress of the cement stone changes in a manner similar to the change in its expansion. The stabilisation of expansion is accompanied by stabilisation of self-stress of cement stone. Results The relationship of self-stress, strength and porosity of concrete for injection with a two-stage expansion on the duration and humidity conditions of hardening, taking into account the conditions of deformation limitation at the first stage, is revealed. Conclusion During prolonged hardening in an aqueous medium, self-stresses are reduced up to 25% with the exception of expansion at the first stage and up to 20% with an increase in volume up to 5% at the first stage. The increase in compressive strength is up to 28% relative to
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Viaducto sobre el rio Llobregat de la Autopista Barcelona-Tarragona, España
Directory of Open Access Journals (Sweden)
Fernández Casado, C.
1973-02-01
Full Text Available Situated in the vicinity of Barcelona, over the LIobregat River, this viaduct bears two roadways 16 meters wide and 440 meters long. It is a continuous viaduct formed of 11 sections of 40-meter spans and S double T section beams placed 3.35 meters apart. The bridge supports are also of double T formation, with a 2.5 meters wide vertical octagonal stem and changing in depth from 2 to 0.7 meters at the edge. The lower footing is supported on 9 piles each 1 meter in diameter. The 80 t beams were prefabricated in the factory and later put in place using a movable formwork. The continuity between beams was made possible by reinforcement placed in the upper slab of the deck and the lower part of the beams. A detailed study has been made on the redistribution of bending moments by creep and shrinking.Situado en las proximidades de Barcelona, y sobre el río Llobregat, está formado por dos calzadas de 16 m de ancho y 440 m de longitud. Es un viaducto continuo que consta de 11 vanos de 40 m de luz, cada uno de los cuales se compone de cinco vigas sección doble T con separación entre ellas de 3,35 metros. Las pilas sobre las que reposa tienen también forma doble T con fuste vertical octogonal de 2,5 m de ancho, cabezal superior en transición poligonal, hasta el borde, variable de 2 a 0,7 m y zapata inferior que se apoya sobre 9 pilotes de 1 m de diámetro. Tanto las vigas como el cabezal de las pilas están pretensados con cables de 150 toneladas. Las vigas de 80 t de peso fueron prefabricadas en taller y colocadas en obra por medio de una cimbra de lanzamiento. La continuidad entre vigas se realizó por medio de armadura pasiva, colocada en la losa superior del tablero y en la parte inferior de las vigas. Se ha llevado a cabo un estudio detallado de la redistribución de momentos flectores por fluencia y retracción.
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MacDonald Dam reconstruction : using roller-compacted concrete
Energy Technology Data Exchange (ETDEWEB)
O' Neil, E. [AMEC Earth and Environmental Ltd., Sydney, NS (Canada)
2007-04-01
Located in Nova Scotia, the MacDonald Dam was commissioned in 1928. The dam consists of a 122 metre-long, 16 metre-high concrete structure comprised of an intake structure, stoplog openings, and a 34 metre-long free-overflow spillway. A 488 metre-long power canal was added as an upgrade in the 1950s. This paper provided details of the roller-compact concrete (RCC) used in the dam's recent rehabilitation following a dam failure analysis in 2003 by Nova Scotia Power Inc. RCC was chosen to help keep the dam's construction project on schedule. The layout and cross-section of the spillway was selected with consideration given to the RCC placing operation. A lift thickness of 0.20 m was selected. A formed ogee crest consisting of conventional reinforced concrete was constructed on top of the RCC. The downstream steps of the spillway were also covered with cast-in-place concrete. A low level sluice was designed to resist the weight of the wet RCC. The design compressive strength of the RCC was 20 MPa. The forms used to support the cast-in-place facing concrete on the upstream face of the dam were constructed full height and were braced back to the downstream face of the existing concrete structure prior to the start of RCC placement. Formwork inserts were placed in the facing concrete as construction progressed. Crack inducers were pre-placed on the forms. Aggregates from a local source were transported to a pug mill as the RCC construction progressed. The RCC was spread into 0.20 m lifts using a small bull-dozer, and the facing concrete was vibrated into the lift below. RCC lifts were compacted using a 9 tonne vibratory drum roller. The RCC placing operation was completed over a period of 10 days. Following the completion of the RCC portion of the dam, the remainder of the cast-in-place concrete was completed. It was concluded that the RCC provided a durable, low-maintenance structure that was completed at a lower price and in a shorter time-frame than
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Structural response of nuclear containment shield buildings with unanticipated construction openings
Mac Namara, Sinead Caitriona
As Nuclear Power Plants age many require steam generator replacement. There is a nickel alloy in the steam generator tubes that is susceptible to stress cracking and although these cracks can be sealed the generator becomes uneconomical without 10%-15% of the tubes. The steam generator in a typical nuclear power plant is housed in the containment structure next to the reactor. The equipment hatch is not big enough to facilitate steam generator replacement, thus construction openings in the dome of the containment structure are required. To date the structural consequences of construction openings in the dome have not been examined. This thesis examines the effects of such openings. The prototype concrete dome is made up of a 2 ft thick dome atop 3 ft thick and 170 ft high cylindrical walls (radius 65.5 ft) with a tension ring 15 ft high and 8 ft thick in between. The dome of the building is cast in two layers; a lower 9 inch layer that serves as the formwork for an upper 15 inch layer. The weight of the dome is carried in axial compression along the hoops and meridians of the dome. The first finite element model uses shell elements and considers two limiting load cases; where the two layers act as one, and where the lower layer carries the weight of both. The openings interrupt the hoops and meridians and the weight of the dome must be redistributed around the openings. Without openings, the stresses due to dead load in the structure are very low when compared to the material strength. The impact of the openings is increased compression stresses near the opening. The maximum stresses are approximately four times larger than in the original structure. These results are confirmed by the second model which is made from layers of solid elements. This model shows a significant difference between the compression on the top surface of the dome, in the affected areas, and that on the bottom surface, leading to shear stresses. These shear stresses are largest around the
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Palacio de deportes de Urdorf – Suiza
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Schwarz, F.
1975-07-01
Full Text Available The sports palace of Urdorf is a complex with various indoor and outdoor sports installations. In the first category are: the sports hall, dividable into two different sporting grounds by means of a partition that is let down from the ceiling; the swimming pool, divided into two zones, one reserved for the teaching of swimming and the other for swimmers; and a sauna for 10 people. In the second category are: a sporting ground, 50 x 30 m, and a 120 m long runway. Both of these are located on the roof of the underground parking place that completes the unit. The building was constructed with prefabricated beams and columns, by means of sliding formwork. The roof is made of panels of isolating cement, which fill a second acoustic function. The facades are entirely of glass, except the western one. The hollows between the structural members were used to canalize all the technical installations of the building.El palacio de deportes de Urdorf es un complejo que cuenta con varias instalaciones deportivas en local cerrado y al aire libre. Entre las primeras destacan: la sala de depor¬tes, desdoblable en dos campos de juego dife¬rentes mediante un tabique que desciende del techo; la piscina, dividida en dos zonas para la práctica de la natación y la enseñanza; y una sauna para 10 personas. Y entre las segundas: un campo de juego de 50 x 30 m, y una pista de 120 m de longitud, organizadas ambas sobre el techo del aparcamiento subterráneo que com¬pleta el conjunto. El edificio se realizó con vigas y pilares prefa¬bricados, a base de encofrados deslizantes. El techo es de paneles de hormigón aislante, que cumplen una segunda función acústica. Las fa¬chadas están completamente acristaladas, a ex¬cepción de la del oeste. Los huecos que quedaban entre los elementos estructurales se utilizaron para llevar las cana¬lizaciones de todas las instalaciones técnicas.
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Pista de pruebas para automóviles de la Opel, Alemania
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Stark, H.
1968-11-01
Full Text Available The need to have the use of all kinds of road surfaces for car testing led to the construction of the experimental car track by the Adam Opel AG. This has been a full experience in this kind of work. The making of a purposely defective road surface has been more difficult than was supposed, and the fast track, provided with all kinds of modern devices, has been studied to its minutest details. Its transversal section (a cubic parabola, with strong camber, made it impossible to use normal machinery, which is only apt for plane surfaces. A type of sliding formwork on rails, suitable for continuous concreting, was adopted. The total length of the track is 32 km. It includes a concrete base and a variable surface, which incorporates all kinds of surfaces that may be met with, in any state of repair. The construction time was 235 days.El imperativo de tener que disponer tramos de carretera de todos los tipos conocidos, trajo como consecuencia que la construcción de la pista de pruebas para los automóviles de la Adam Opel AG haya constituido una experiencia completa en esta clase de trabajos. La realización de un piso intencionadamente defectuoso ha resultado ser más difícil de lo que se creía en principio, y la pista rápida, que está dotada de toda clase de adelantos y de máxima seguridad, ha sido estudiada hasta en sus más mínimos detalles. Su sección transversal (una parábola cúbica, fuertemente inclinada, obligó a desechar la maquinaria normal, sólo apta para superficies planas, y a adoptar un tipo de encofrado deslizante, especial para hormigonado continuo, que se movía sobre carriles. El trazado total es de 32,2 km, con un lecho de hormigón, y un pavimento variable que abarca todos los que se pueden presentar en carreteras de distintas categorías y en cualquier estado de conservación. La duración de las obras fue de 235 días.
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MODERN METHODS OF DESIGN AND ARRANGEMENT OF RAMMING PILES IN PUNCHED HOLES
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ZOTSENKO N. L.
2015-10-01
Full Text Available Problem statement. Ramming piles in punched holes (RPPH differ of high degree of use of supporting capacity of base because of forming in it a compacted zone at the expense of displacement of soil in the volume rammer and compacted material of expansion. The method of their construction almost exclude excavation and formwork, reducing the consumption of concrete, metal, accelerates zero cycle compared to the foundations raised and excavation and immersion into the soil of precast elements. The expansion of the normative base, their design and construction should be for further implementation of of natural objects. The correctness of the geomechanical model of plane and spatial version of finite element method (FEM should be proved for the calculation of cooperative work of RPPH as part of grillages with base. The most effective kinds of equipment and technological schemes of construction of RPPH should be noticed. Conclusions. The paper presents the main regulations on the design and the arrangement RPPH, corresponding of construction norms of Ukraine. The results of experimental and theoretical studies conducted by the authors for over thirty years, and the experience of the use of these piles on the objects of civil engineering, industrial and agricultural construction made their base. The use of the elastoplastic model with the criterion of Mohr-Coulomb strength for designing of the system "grillage -RPPH- soil" was substantiated. The designing in plane and spatial problems of FEM is proved that in the distance between the axes of adjacent piles up to five diameters is a correct choice of a flat version and simplifying of calculating scheme to the conventional strip foundation. An improved. The method of calculating of RPPH as part of grillages ribbon, where as the width of the foundation was taken a diameter of the broadening of the pile, and the depth of its inception corresponds to the bottom of it. The supporting layer of base under the
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Modelling of Edge Insulation Depending on Boundary Conditions for the Ground Level
Stolarska, Agata; Strzałkowski, Jarosław
2017-10-01
The article presents results of CFD software aided simulations of a thermal bridge, existing at the wall-slab on ground connection. Calculations were made for different variants of the edge insulation location. Schemes without any edge insulation, with some vertical insulation, horizontal, diagonal, and diagonal combined with insulation used as formwork under the slab on ground were analysed. Each variant was differentiated with boundary conditions for the ground. Vertical borders of the model in the ground, as well as the lower border were described in the first solution as adiabatic, while in the second case, a variable temperature value, depending on the ground depth, was set. For comparison, additional calculations were conducted for non-stationary conditions, in which the initial temperature of the ground was set to the average annual temperature of air. The calculations were based on the location of Szczecin, for which the outside air temperature was set to -16.0°C. Results obtained from the simulation were then used to determine the thermal bridge parameters, in particular, thermal coupling coefficient and linear thermal transmittance. The effect of the set of boundary conditions is clearly seen. In general, for all the five variants, lower values of heat fluxes and linear thermal transmittances were obtained, when variable temperature in the ground was assumed. From the point of view of energy balance, it is more favourable to use the values of ψg obtained when the ground temperature is taken into account. The data breakdown shows that application of the actual temperature distribution in the ground to a model has a strong effect on distribution of the 0.0°C isotherm. The adiabatic model indicates that the ground under the slab freezes, while the model, which takes into account the temperature of the ground, shows that the ground under the floor has positive temperatures and the 0.0°C isotherm reaches only the edge of the outer wall. Moreover, the
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El puente Bendorf sobre el Rin (Alemania
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Hirschfeld, Kurt
1966-03-01
Full Text Available This recently completed bridge over the Rhine is 524 m long, and is a reinforced concrete structure, built by successive overhangs, without the aid of formwork or scaffolding. The centre span is 208 m in length, and the other six vary between 43 and 71 m. The deck consists of two independent parts, including a continuous box girder, with a hinge at the crown of the main span. It is stiffened with transversal diaphragms, spaced every 34 m. The piles rest on pneumatic caissons, which go down to 16 m below the river bed. The attachment between the piles and the caissons is rigid, at the central pile, and at the other piles it operates through a roller bearing. The central span was constructed without intermediate supports for the first 40 m, and beyond that stage, for greater safety, a provisional movable tower was built, as a temporary point of support for the free overhang. The various sections were concreted and post-tensioned with 32 mm bars, by the Dywidag procedure. Account was taken of the varying deformations that took place at each section, so as to add the necessary counter-deflection that finally enabled the two sides of the arch to meet at the crown at the calculated point.Este puente, recientemente construido, sobre el Rin, tiene una longitud total de 524 m, es de hormigón armado y se ha realizado por el procedimiento de voladizos sucesivos, sin entramado auxiliar ni cimbras. La luz del tramo central es de 208 m, y las de los otros seis oscilan entre 43 y 71 m. La estructura del tablero se compone de dos partes independientes, formadas por una viga tipo cajón, continua, con una articulación en la clave del tramo central y rigidizada con diafragmas transversales espaciados a 34 m. Las pilas centrales se apoyan sobre cajones neumáticos que descienden 16 m debajo del fondo del río. La unión entre estas pilas y la estructura cajón es rígida, y de tipo rodillo en las otras pilas. El tramo central se ha construido por voladizos
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Puente de hormigón pretensado sobre el río Caroni
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Fernández, Álvaro
1964-06-01
Full Text Available This bridge consists of a. series of portal frames, of 96 m span each, making up a total length of about 500 m. The piles over the river have caused certain difficulties, and it became necessary to build a number cofferdams with sheetpiling, which became permanent formwork for the concrete foundations. The deck is a box section beam, of prestressed concrete. The most notable aspect of this structure is the constructive method. The total length of the deck was divided into 50 sections, each of them prefabricated at a nearby workshop. Each section was aligned along the deck axis: the deck already built serving as sliding ramp for each successive section. To carry out this difficult operation, neoprene was employed, which has a very low friction coefficient, on sliding over steel. To push the heavy table sections to their final position use has been made of hydraulic jacks. After these initial operations were completed, the groups of prestressed cables were correctly aligned: these cables had been provisionally stretched, during the process of putting the deck sections together. These groups of cables are attached to the inner surface of the side walls of the box sections of the deck.Este puente consta de una serie de tramos porticados de luces máximas (96 m , con longitud total de unos 500 metros. Las pilas o soportes han presentado cierta dificultad en los tramos correspondientes al río, pues han sido necesarias ataguías formadas por células de tablestacas que han servido de encofrados perdidos para hormigonar los cimientos. El conjunto del tablero está constituido por una viga-cajón, de hormigón pretensado. La particularidad más notable de esta estructura radica en los métodos constructivos llevados a cabo en su realización. La longitud total del tablero se ha subdividido en 50 trozos prefabricados en un taller próximo al puente y alineado con el eje del mismo, que ha servido de rampa para el traslado y corrimiento a su posici
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International Nuclear Information System (INIS)
Vasilic, Ksenija
2016-01-01
This thesis addresses numerical simulations of self-compacting concrete (SCC) castings and suggests a novel modelling approach that treats reinforcement zones in a formwork as porous media. As a relatively new field in concrete technology, numerical simulations of fresh concrete flow can be a promising aid to optimise casting processes and to avoid on-site casting incidents by predicting the flow behaviour of concrete during the casting process. The simulations of fresh concrete flow generally involve complex mathematical modelling and time-consuming computations. In case of a casting prediction, the simulation time is additionally significantly increased because each reinforcement bar occurring in succession has to be considered one by one. This is particularly problematic when simulating SCC casting, since this type of concrete is typically used for heavily reinforced structural members. However, the wide use of numerical tools for casting prediction in practice is possible only if the tools are user-friendly and simulations are time-saving. In order to shorten simulation time and to come closer to a practical tool for casting prediction, instead to model steel bars one by one, this thesis suggests to model zones with arrays of steel bars as porous media. Consequently, one models the flow of SCC through a reinforcement zone as a free-surface flow of a non-Newtonian fluid, propagating through the medium. By defining characteristic parameters of the porous medium, the influence on the flow and the changed (apparent) behaviour of concrete in the porous matrix can be predicted. This enables modelling of any reinforcement network as a porous zone and thus significantly simplifies and fastens simulations of reinforced components' castings. Within the thesis, a computational model for SCC flow through reinforced sections was developed. This model couples a fluid dynamics model for fresh concrete and the macroscopic approach for the influence of the porous medium
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El envejecimiento de las pastas de cemento reforzadas con fibras de vidrio
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Sánchez Paradela, M. L.
1992-06-01
Full Text Available Cement pastes reinforced with glassfibre, popularly called GRC ("Glassfibre Reinforced Cements" are compound materials which have been widely used in the construction field for the last 30 years. Their good mechanical properties, lightness and resistance to corrosion and fire make them suitable in the process of replacing the fibrocements with asbestos base in numerous applications. For that reason, their use has been extended in recent years and they have mainly been used to manufacture panels for facades and interior decoration as well as, to a smaller extent, for plumbing installations, roofs, lost formwork and even for "fingers" at the airports (1, 2, 3, 4, 5. Nevertheless, it has been known for over 25 years that GRC suffer deterioration with the time which affects their mechanical properties and especially their tenacity; they become fragile and crack under small deformations. The research carried out to determine the causes of the phenomenon and look for possible solutions has been intense and it would be impossible to give more details here due to the lack of space. We will try, nevertheless, to summarize some more relevant aspects of the problem and the solutions that have reached the highest point of development so far.
Las pastas de cemento reforzadas con fibras de vidrio, denominadas popularmente GRC ("Glassfibre Reinforced Cements", son materiales compuestos que se utilizan ampliamente en el campo de la Construcción desde hace unos 30 años. Sus buenas propiedades mecánicas, ligereza y resistencia a la corrosión y al fuego les hacen idóneos en el proceso de sustitución de los fibrocementos de base amianto en numerosas aplicaciones. Por tal motivo, su empleo se ha extendido en los últimos años, utilizándose fundamentalmente para fabricar paneles de cierre de fachadas y decoración de interiores y en menor grado para tuberías, cubiertas, encofrados permanentes e incluso para "fingers" o brazos de acceso a los aviones -
Energy Technology Data Exchange (ETDEWEB)
Vasilic, Ksenija
2016-05-01
This thesis addresses numerical simulations of self-compacting concrete (SCC) castings and suggests a novel modelling approach that treats reinforcement zones in a formwork as porous media. As a relatively new field in concrete technology, numerical simulations of fresh concrete flow can be a promising aid to optimise casting processes and to avoid on-site casting incidents by predicting the flow behaviour of concrete during the casting process. The simulations of fresh concrete flow generally involve complex mathematical modelling and time-consuming computations. In case of a casting prediction, the simulation time is additionally significantly increased because each reinforcement bar occurring in succession has to be considered one by one. This is particularly problematic when simulating SCC casting, since this type of concrete is typically used for heavily reinforced structural members. However, the wide use of numerical tools for casting prediction in practice is possible only if the tools are user-friendly and simulations are time-saving. In order to shorten simulation time and to come closer to a practical tool for casting prediction, instead to model steel bars one by one, this thesis suggests to model zones with arrays of steel bars as porous media. Consequently, one models the flow of SCC through a reinforcement zone as a free-surface flow of a non-Newtonian fluid, propagating through the medium. By defining characteristic parameters of the porous medium, the influence on the flow and the changed (apparent) behaviour of concrete in the porous matrix can be predicted. This enables modelling of any reinforcement network as a porous zone and thus significantly simplifies and fastens simulations of reinforced components' castings. Within the thesis, a computational model for SCC flow through reinforced sections was developed. This model couples a fluid dynamics model for fresh concrete and the macroscopic approach for the influence of the porous medium
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Tribuna del Hipódromo de Montebello
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Boico, Romano
1964-09-01
Full Text Available A new stand has been built at the Montebello Race Course, in Trieste, Italy. The project also includes all ancillary services. The design assumed a maximum wind velocity of 180 km/hr, as this order of wind strength is not unusual in that district. Every effort has also been made to provide fine visibility and protection against wind and rain. The final solution is based on the provision of a number of reinforced concrete trusses, which constitutes a very interesting structural manifold. Each truss consists of a main support, a side beam which helps to sustain the stand, a horizontal stabilising member, and a top cantilevered rib extending on both sides of the vertical member. The surface over the stand is an overhanging concrete slab supported on the ribs: this slab also extends behind the stand. The main supports rest on concrete footings, whilst the side beam is attached to the foundations by means of a hinge. Building started with the stands, as these were to support the formwork for the construction of the roofing slab and the powerful ribs on which the slab rests.En Trieste (Italia se ha construido una nueva tribuna para el hipódromo de Montebello, con el complemento de todos los servicios adecuados. En el proyecto se contó con un efecto de viento de hasta 180 km/hr —por ser bastante frecuente en esta zona italiana—, y se ha procurado obtener gran visibilidad y resguardo contra vientos y lluvias. La solución adoptada fue a base de una serie de cerchas, de hormigón armado, que forman una estructura con un sello particular. Cada cercha se compone de: un soporte principal, una zanca que sirve de apoyo al graderío, una viga horizontal de arriostramiento y un nervio superior que se proyecta en voladizo a una y otra parte del eje de soportes. El brazo que cubre la tribuna es una ménsula curva hormigonada entre los nervios superiores, y el brazo posterior a la tribuna, de escasa importancia, está formado por la prolongación de una losa
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Thick Concrete Specimen Construction, Testing, and Preliminary Analysis
Energy Technology Data Exchange (ETDEWEB)
Clayton, Dwight A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Hoegh, Kyle [Univ. of Minnesota, Minneapolis, MN (United States); Khazanovich, Lev [Univ. of Minnesota, Minneapolis, MN (United States)
2015-03-01
The purpose of the U.S. Department of Energy Office of Nuclear Energy’s Light Water Reactor Sustainability (LWRS) Program is to develop technologies and other solutions that can improve the reliability, sustain the safety, and extend the operating lifetimes of nuclear power plants (NPPs) beyond 60 years. Since many important safety structures in an NPP are constructed of concrete, inspection techniques must be developed and tested to evaluate the internal condition. In-service containment structures generally do not allow for the destructive measures necessary to validate the accuracy of these inspection techniques. This creates a need for comparative testing of the various nondestructive evaluation (NDE) measurement techniques on concrete specimens with known material properties, voids, internal microstructure flaws, and reinforcement locations. A preliminary report detailed some of the challenges associated with thick reinforced concrete sections and prioritized conceptual designs of specimens that could be fabricated to represent NPP concrete structures for using in NDE evaluation comparisons. This led to the construction of the concrete specimen presented in this report, which has sufficient reinforcement density and cross-sectional size to represent an NPP containment wall. Details on how a suitably thick concrete specimen was constructed are presented, including the construction materials, final nominal design schematic, as well as formwork and rigging required to safely meet the desired dimensions of the concrete structure. The report also details the type and methods of forming the concrete specimen as well as information on how the rebar and simulated defects were embedded. Details on how the resulting specimen was transported, safely anchored, and marked to allow access for systematic comparative NDE testing of defects in a representative NPP containment wall concrete specimen are also given. Data collection using the MIRA Ultrasonic NDE equipment and
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Ejecución de puentes pretensados por voladizos sucesivos (Continuación
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Fernández Casado, Carlos
1964-03-01
Full Text Available The system of construction whereby successive extensions of a cantilevered structure are carried out has made it possible to extend, to an extraordinary extent, the free spans of straight section prestressed concrete bridges. At present the Bendorf bridge is being constructed, whose central span is 208 m long. This system was first used in Brazil, for the construction of an ordinary reinforced concrete bridge over the river Peixe. But the method fell into disuse, except for very few exceptions, until Firsterwalder again brought it up to date 20 years later, when building the Neckar bridge, made of prestressed concrete. With this new technique all the advantages of the system could be exploited, as well as achieving a very rapid construction. This constructional procedure leads directly to the structural type known as compensated cantilevers. T shaped cells are attached together by means of prestressing cables to form advancing cantilevers. Thereby a, total bridge structure is formed, whose span is twice that of each cantilevered half. This method can be applied to other bridge types, such as dintels with overhanging sections (this was the first new application, single span portal frames, T portal frames, continuous beams, etc. The typical constructional method is to move the formwork, which is anchored and cantilevered beyond the constructed part. A weekly progress of 3,50 m is normal. It is also possible to employ prefabricated sections, which are successively joined to the ones already in place.El sistema de construcción por voladizos sucesivos ha permitido ampliar, de modo extraordinario, las luces de los puentes de tramo recto de hormigón pretensado. Actualmente se construye el Puente de Bendorf con tramo central de 208 metros. Se utilizó por primera vez en Brasil para la construcción de un puente de hormigón armado normal sobre el río Peixe, pero quedó en desuso—salvo poquísimas excepciones—hasta que lo volvió a poner a punto
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Bender, O.
1965-07-01
Full Text Available The Redwood highway, through the Californian forest, runs on a viaduct, as it crosses a mountain slope of about 45° inclination. The firm ground is fairly deep, and as an additional constructional difficulty, it was necessary to respect the natural beauty of the countryside. A structure of portal frames were built, forming a number of short spans. These spans were bridged with metal girders, on which a 19 m wide deck was placed. The columns are hollow and have a transversal cross beam, to join each pair. There was difficulty in excavating the foundations for the columns, as it was necessary to dig through the soft top soil, and also prevent this soil from hurting the trunks of the forest trees. Another significant difficulty in the construction of this viaduct was the access to the working site, since there were no suitable platforms from which to operate the appropriate machinery. This made it necessary to do a lot of the work by manual operation. As one of the edges of the deck is very close to the mountain side, a supporting beam was erected on this side. It was made of concrete, on metal piles. The formwork for the deck structure was placed on the concrete stems of the supporting piles.La autopista denominada Redwood (California salva, con un paso superior, la ladera de un bosque cuya pendiente es del 1/1. El terreno firme se halla a bastante profundidad, añadiéndose, a los naturales problemas de la construcción, el imperativo de respetar la belleza agreste del paraje. La solución adoptada consiste en una estructura porticada, con varios tramos de pequeñas luces, salvados con vigas metálicas, sobre los que se coloca la losa del tablero, de 19 m de anchura total. Los soportes están constituidos por pórticos de dos montantes huecos (con bases de hormigón en masa por debajo del suelo, hasta el firme coronados por un cabezal. La perforación de pozos para el hormigonado de los montantes presentaba la dificultad de atravesar el terreno
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Caramés Gómez, Fernando
2007-06-01
Full Text Available This account of the design and construction of an outdoor auditorium in a park in Madrid begins with the study of the programme and choice of the shape and optimal materials for the roof. The solution adopted was to build with wood paraboloids in light of the large surface area that could be covered, the lightweight supports that could be used, the powerful and original image that would be projected and the short turnaround times and moderate cost that could be ensured.Wooden roof building began with the manufacture of a steel frame to support the ruling that sweeps the hyperbolic paraboloid. This frame was also to support removable self-bearing formwork that would constitute the fi rst row and have a load capacity able to support the entire weight of the roof in addition to acting as a guide for the rest of the structure. The next row was bolted and glued to this fi rst family of elements and each successive row was laid on the one before it.Double “omega” members made of circular section steel shapes, separated by an acutely angled opening, were designed as supports for the paraboloids. These elements brace the structure as a whole by allowing for the positioning of longitudinal reinforcements in the outermost supports.El artículo describe el proceso de diseño y de construcción de un auditorio al aire libre en un parque en Madrid. Comienza con el estudio del programa y la elección de la forma y los materiales óptimos de la cubierta. Se decidió la construcción de paraboloides de madera al tener la característica de poseer una gran superficie cubierta, permitir apoyos ligeros, crear una imagen poderosa y original, permitir unos plazos de ejecución pequeños y un coste moderado.La ejecución de las cubiertas de madera se inicia ediante la fabricación de un bastidor de acero obre el cual se apoya la generatriz que engendra el paraboloide hiperbólico. Este bastidor debe ervir a su vez de apoyo a una cimbra recuperable autoportante
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Edificio circular de oficinas Arcis-Sur-Aube – Francia
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Bayonne, Philippe
1972-10-01
Full Text Available This building has a very particular shape, as a result of the following ideas, which conditioned the initial project: — It was sought to integrate the whole staff within a single zone to give them a closer mutual relationship. — Seek to avoid the classical design, of broken up spaces, with many internal partitions, corridors and doors. — The building to operate as a control tower over the general activity of the whole works. — On the ground level, to have an additional free space for the storage of beet, during the harvesting period. In general terms the building consists of a circular stem, of reinforced concrete, housing the lift and stairs. Around it the office flooring structure is cantilevered, from this single support. The building is completed with a truncated cone roof, which houses, on two floor levels, the records rooms. The most important problems were the construction of the flooring reinforcement work and the formwork for the external surfaces. The first difficulty was overcome by means of four double girders, placed orthogonally, in couples, supported on the stem periphery; whilst the second was solved by using plywood on transversal and radial framework.Se trata de una construcción de forma muy particular, como consecuencia de las siguientes ideas que sirvieron de base para el proyecto: tender hacia una solución colectiva que, reuniendo al personal técnico bajo un mismo polo, les confiriera una más estrecha relación; huir de la solución «clásica » de plantas quebradas, con profusión de divisiones interiores, pasillos y puertas; función de torre de control sobre la actividad general de la fábrica, y disponer, al nivel del terreno, de superficie libre adicional para el almacenaje de remolacha en las épocas de recogida. El edificio en líneas generales consta de un fuste circular, central, de hormigón armado, que aloja en su interior al ascensor y a la escalera. En su periferia se apoya el forjado de la planta
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Ejecución de puentes pretensados por voladizos sucesivos
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Fernández Casado, Carlos
1963-12-01
Full Text Available The system of construction whereby successive extensions of a cantilevered structure are carried out has made it possible to extend, to an extraordinary extent, the free spans of straight section prestressed concrete bridges. At present the Bendorf bridge is being constructed, whose central span in 258 ms long. This system was first used in Brazil, for the construction of an ordinary reinforced concrete bridge over the river Peixe. But the method fell into disuse, except for very few exceptions, until Firsterwalder against brought it up to date 20 years later, when building the Neckar bridge, made of prestressed concrete. With new technique all the advantages of the system could be exploited, as well as achieving a very rapid construction. This constructional procedure leads directly to the structural type known as compensated cantilevers. T shaped cells are attached together by means of prestressing cables to form advancing cantilevers. Thereby a total bridge structure is formed, whose span is twice that of each cantilevered half. This method can be applied to other bridge types, such as dintels with overhanging sections (this was the first new application, single span portal frames, T portal frames, continuous beams, etc. The typical constructional method is to move the formwork, which is anchored and cantilevered beyond the constructed part. A weekly progress of 3,50 ms is normal. It is also possible to employ prefabricated sections, which are successively joined to the ones already in place. (Owing to the length of this article, it will be published in several successive issues.El sistema de construcción por voladizos sucesivos ha permitido ampliar, de modo extraordinario, las luces de los puentes de tramo recto de hormigón pretensado. Actualmente se construye el puente de Bendorf con tramo central de 258 metros. Se utilizó por primera vez en Brasil para la construcción de un puente de hormigón armado normal sobre el río Peixe, pero
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Ejecución de puentes pretensados por voladizos sucesivos
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Fernández Casado, Carlos
1964-02-01
Full Text Available The system of construction whereby successive extensions of a cantilevered structure are carried out has made it possible to extend, to an extraordinary extent, the free spans of straight section prestressed concrete bridges. At present the Bendorf bridge is being constructed, whose central span is 358 m long. This system was first used in Brazil, for the construction of an ordinary reinforced concrete bridge over the river Peixe. But the method fell into disuse, except for very few exceptions, until Firsterwalder again brought it up to date 20 years later, when building the Neckar bridge, made of prestressed concrete. With this new technique all the advantages of the system could be exploited, as well as achieving a very rapid construction. This constructional procedure leads directly to the structural type known as compensate cantilevers. T shaped cells are attached together by means of prestressing cables to form advancing cantilevers. Thereby a total bridge structure is formed, whose span is twice that of each cantilevered half. This method can be applied to other bridge types, such as dintels with overhanging sections (this was the first new application, single span portal frames, T portal frames, continuous beams, etc. The typical constructional method is to move the formwork, which is anchored and cantilevered beyond the constructed part. A weekly progress of 3,50 m is normal. It is also possible to employ prefabricated sections, which are successively joined to the ones already in place. (Owing to the length of this article, it will be published in several successive issues.El sistema de construcción por voladizos sucesivos ha permitido ampliar, de modo extraordinario, las luces de los puentes de tramo recto de hormigón pretensado. Actualmente se construye el puente de Bendorf con tramo central de 258 metros. Se utilizó por primera vez en Brasil para la construcción de un puente de hormigón armado normal sobre el río Peixe, pero
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El viaducto de San Giuliano, en Italia
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Cestelli Guidi, Carlo
1965-10-01
Full Text Available This viaduct is part of the Sun Roadway, along the western coast of Italy. It is a reinforced concrete structure, with prestressed girders. It runs over a deep ravine, through which water flows intermittently into the Tiber river, a little below the bridge. As the hillside is not highly stable, the possibility of building a large arch was excluded, since the thrusts at the springers would be large. The total length to be bridged, 376 m, has been divided into three approach spans, each 32 m long, on one side, a further five spans, of similar length, on the other side, and a central 100 m long span. The remaining 20 m are taken up with the width of the piles. The project consists of two independent, twin bridges, since there is a separate structure for each of the two traffic directions. The width of each runway is 7.50 m. The planform of the bridge is S shaped, with a central straight section of 106 m length, and a maximum height of 74 m. The piles, of great height, are hollow columns, of rectangular cross section, and concreted by means of sliding formwork. The central span is the most Important feature of the project. It constitutes a portal fram .together with the two supporting piles. These slope towards the centre of the span. The intrados is arched shaped, and the extrados is the deck itself. The attachment of this central span with the springers is through hinged joints, consisting of reinforced neoprene plates. The straight sections of the bridge, of 32 m length, have been spanned with prestressed, prefabricated beams.Este viaducto, en la Autopista del Sol (Italia, es de hormigón armado con vigas pretensadas. Salva una vaguada profunda de aguas intermitentes que se unen al río Tíber en las proximidades del puente. Como las laderas de apoyo tienen poca consistencia se excluyó la solución de un arco de gran luz, dada la importancia del empuje en estos casos. Su longitud total es de 376 m, divididos en tres tramos de acceso de 33 m de
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Kabantsev Oleg Vasil'evich
2013-09-01
Full Text Available The methods and techniques used to estimate calculations can give us quite an adequate prediction of stress-and-strain state of load-bearing structures of traditional buildings with simple architectural forms.Traditional calculation methods take the basic parameters of a designe model as constant: a set of elements of a model, their geometry and stiffness properties, external relations with the environment. Loads upon the model are also taken as constant. However, the creation of even relatively simple structures is not a single-stage process. Building is a multistage process, where one may single out separate stages of "closing" a local subsystem of a structure. Each of the operations determines a certain stage of the building process characterized by a definite design model that differs from the design model of a complete structure.Consideration of stagewise changes in the design model parameters is especially necessary in the process of designing high-rise buildings with reinforced concrete framing. The thing is that while constructing each floor the formwork is put in the position predetermined by the design, thus ignoring deformations of the lower structures. The calculation technology is based on the principles of stagewise change tracking in the basic parameters of the design model with the subsystem closing at each stage of construction. All the calculations are made presuming validity of common assumptions in the linear structural mechanics for each stage. Generally, that problem becomes non-linear at the expense of changing the design model in the course of transition from one stage to another. Typically, a special case of operating period begins after some time of normal operation. Hence, the stress-and-strain state of load-bearing structure system that appeared during the main operating period was an initial condition for the next stage of analysis. The problem of an accurate prediction of stress-and-strain state for buildings and
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156 Viviendas Industrializadas en Vitoria-Gasteiz
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López del Corral, J. J.
2009-03-01
works were awarded to the joint venture formed by CONSTRUCCIONES SUKIA and NORTEN PH. Construction will be completed in mid-2009. A comparative study was also conducted (by PICH in conjunction with IMAT of two developments in the same sector. The scope was as follows: comparative analysis of two residential buildings, one industrialized and the other built with traditional construction systems, using real site data. The preliminary results are discussed in this article. The final conclusions will be drawn after the works are completed. Concrete industrialization (linear or three-dimensional is one of a number of possible alternatives (composite and steel construction. Other parts of the process can also be industrialized (formwork for instance. Residential building structures can and should, in the author’s opinion, adopt the pattern used in commercial building (today’s industrial bays are made of steel or precast concrete, for this is technically possible. Work site visits have been organized for groups of ten architects and engineers; to date nearly 600 have visited the development.Durante el año 2004, VISESA convocó una Beca de Investigación sobre Estructuras Industrializadas en Edificios de Vivienda Colectiva. Fue desarrollada por el equipo Pich-Aguilera y se concluyeron una serie de desajustes actuales en el sector (en concreto en los campos energético, social y económico que podrían solucionarse con sistemas industrializados. * Analisis de sistemas valorados en la Beca: – Paneles de fachada. – Sistema entramado (esqueleto de pilares y jácenas. – Sistema tridimensional (paramentos, cajas o módulos. – Sistema mixto (esqueleto, placas y módulos. * Análisis de posibilidades de contratación, asociaciones y empresas valorados en la Beca. * Análisis comparativo realizado en la Beca entre una obra industrializada y otra tradicional. Una vez completada la fase de la Beca de Investigación y disponibles los datos teóricos y las conclusiones, a la