WorldWideScience

Sample records for caissons

  1. Dynamic stiffness of suction caissons

    DEFF Research Database (Denmark)

    Ibsen, Lars Bo; Liingaard, Morten; Andersen, Lars

    The purpose of this report is to evaluate the dynamic soil-structure interaction of suction caissons for offshore wind turbines. The investigation is limited to a determination of the vertical dynamic stiffness of suction caissons. The soil surrounding the foundation is homogenous with linear...... of the skirt length, Poisson's ratio and the ratio between soil stiffness and skirt stiffness. Finally the dynamic behaviour at high frequencies is investigated....... viscoelastic properties. The dynamic stiffness of the suction caisson is expressed by dimensionless frequency-dependent dynamic stiffness coefficients corresponding to the vertical degree of freedom. The dynamic stiffness coefficients for the foundations are evaluated by means of a dynamic three...

  2. Dynamic stiffness of suction caissons

    DEFF Research Database (Denmark)

    Ibsen, Lars Bo; Liingaard, Morten; Andersen, Lars

    This report concerns the dynamic soil-structure interaction of steel suction caissons applied as foundations for offshore wind turbines. An emphasis is put on torsional vibrations and coupled sliding/rocking motion, and the influence of the foundation geometry and the properties of the surrounding...

  3. Impedance of flexible suction caissons

    DEFF Research Database (Denmark)

    Liingaard, Morten; Andersen, Lars; Ibsen, Lars Bo

    2007-01-01

    and coupled sliding-rocking vibrations, influence of the foundation geometry and examination on the properties of the surrounding soil. The soil is simplified as a homogenous linear viscoelastic material and the dynamic stiffness of the suction caisson is expressed in terms of dimensionless frequency......-dependent coefficients corresponding to different degrees of freedom. The dynamic stiffness coefficients for the skirted foundation are evaluated using a three-dimensional coupled boundary element/finite element model. Comparisons with known analytical and numerical solutions indicate that the static and dynamic...

  4. Suction caissons subjected to monotonic combined loading

    DEFF Research Database (Denmark)

    Penzes, P.; Jensen, M.R.; Zania, Varvara

    2016-01-01

    Suction caissons are being increasingly used as offshore foundation solutions in shallow and intermediate water depths. The convenient installation method through the application of suction has rendered this type of foundation as an attractive alternative to the more traditional monopile foundation...... for offshore wind turbines. The combined loading imposed typically to a suction caisson has led to the estimation of their bearing capacity by means of 3D failure envelopes. This study aims to analyse the behaviour of suction caissons for offshore wind turbines subjected to combined loading. Finite element...

  5. Dynamic behaviour of suction caissons

    Energy Technology Data Exchange (ETDEWEB)

    Liingaard, M.

    2006-12-15

    Offshore wind energy is a promising source of energy in the near future, and is rapidly becoming competitive with other power generating technologies. The continuous improvement in wind turbine technology means that the wind turbines have increased tremendously in both size and performance during the last 25 years. In order to reduce the costs, the overall weight of the wind turbine components is minimized, which means that the wind turbine structures become more flexible and thus more sensitive to dynamic excitation. Since the first resonance frequency of the modern offshore wind turbines is close to the excitation frequencies of the rotor system, it is of outmost importance to be able to evaluate the resonance frequencies of the wind turbine structure accurately as the wind turbines increase in size. In order to achieve reliable responses of the wind turbine structure during working loads it is necessary to account for the possibilities of dynamic effects of the soil-structure interaction. The aim of this thesis is to evaluate the dynamic soil-structure interaction of foundations for offshore wind turbines, with the intention that the dynamic properties of the foundation can be properly included in a composite structure-foundation system. The work has been focused on one particular foundation type; the suction caisson. The frequency dependent stiffness (impedance) of the suction caisson has been investigated by means of a three-dimensional coupled Boundary Element/Finite Element model, where the soil is simplified as a homogenous linear viscoelastic material. The dynamic stiffness of the suction caisson is expressed in terms of dimensionless frequencydependent coefficients corresponding to the different degrees of freedom. Comparisons with known analytical and numerical solutions indicate that the static and dynamic behaviour of the foundation are predicted accurately with the applied model. The analysis has been carried out for different combinations of the

  6. Structural damage monitoring of harbor caissons with interlocking condition

    Energy Technology Data Exchange (ETDEWEB)

    Huynh, Thanh Canh; Lee, So Young; Nauyen, Khac Duy; Kim, Jeong Tae [Pukyong National Univ., Busan (Korea, Republic of)

    2012-12-15

    The objective of this study is to monitor the health status of harbor caissons which have potential foundation damage. To obtain the objective, the following approaches are performed. Firstly, a structural damage monitoring(SDM) method is designed for interlocked multiple caisson structures. The SDM method utilizes the change in modal strain energy to monitor the foundation damage in a target caisson unit. Secondly, a finite element model of a caisson system which consists of three caisson units is established to verify the feasibility of the proposed method. In the finite element simulation, the caisson units are constrained each other by shear key connections. The health status of the caisson system against various levels of foundation damage is monitored by measuring relative modal displacements between the adjacent caissons.

  7. Study on the breakwater caisson as oscillating water column facility

    Science.gov (United States)

    Huang, Yan; Shi, Hongda; Liu, Defu; Liu, Zhen

    2010-09-01

    The Oscillating Water Column (OWC) wave energy convertor with the advantage of its simple geometrical construction and excellent stability is widely employed. Recently, perforated breakwaters have been often used as they can effectively reduce the wave reflection from and wave forces acting on the structures. Considering the similarity between the compartment of perforated caisson and the air chamber of OWC wave energy convertor, a new perforated caisson of breakwater is designed in this paper. The ordinary caisson is modified by installing facilities similar to the air chamber of OWC converter, but here they are utilized to dissipate the wave energy inside the caisson. Such an arrangement improves the stability of the caisson and reduces the construction cost by using the compartment of perforated caisson like using an air chamber. This innovation has both academic significance and important engineering value. For a new type of caisson, reliability analysis of the structure is necessary. Linear potential flow theory is applied to calculate the horizontal wave force acting on the caisson. The calculated results are compared with experimental data, showing the feasibility of the method. The Importance Sampling Procedure (ISP) is used to analyse the reliability of this caisson breakwater.

  8. Failure Loci of Suction Caisson Foundations Under Combined Loading Conditions

    Institute of Scientific and Technical Information of China (English)

    WANG Dong; JIN Xia

    2008-01-01

    Suction caissons are widely used to support offshore fixed platforms in coastal areas. The loadings transferred to suction caissons include the eccentric lateral force induced by waves and self weight of the platform structure. However, under this kind of combined loading conditions, the failure mechanism of caissons with shallow embedment depths is quite different from conventional deep foundations or onshore shallow footings. The behaviour of caissons subjected to combined loadings may be described with the "failure locus" in force resultant spaces. Here the failure loci of smooth caissons are studied by use of finite element approach, with the embedment ratio of caissons varying in the range of 0.25~1.0 and eccentricity ratio of horizontal loadings in 0~10. The platform settlement and tilt limits are involved into determination of failure loci, thus the platforms can avoid significant displacements for the combined loadings located inside the failure locus. Three families of loading paths are used to map out the locus. It is found that the shape of failure loci depends on 3 non-dimensional parameters, and the failure locus of a given caisson changes gradually from the elliptical curve to hooked curve with increasing shear strength of soil. The lateral capacity of short caissons may be enhanced by vertical forces, compared with the maximum lateral capacity of long caissons occurring at the vertical force being zero. The critical embedment ratios partitioning elliptical and hooked loci are proposed.

  9. Construction Process Control of Large Extra Caissons

    Institute of Scientific and Technical Information of China (English)

    HU Shaowei; WANG Hongxia; FAN Jiansheng

    2005-01-01

    The complexity of geotechnical engineering and variability in construction circumstances of large extra caissons make the problem of maintaining appropriate sink attitude quite difficult, especially in keeping sink uniformity and achieving the expected final sink depth. A new construction control method is presented using (H∞) theory, considering uncertainties in the mechanics model and external noise in the construction site parameters. The design method of an (H∞) controller has consequently been obtained for large extra caissons. Control results using only constructor experiences are compared with simulation results using the (H∞) controller for a practical engineering situation, which indicates that the (H∞) controller is successful in maintaining sink uniformity, avoiding sink as well as in achieving the expected final sink depth.

  10. Dynamic stiffness of suction caissons - vertical vibrations

    Energy Technology Data Exchange (ETDEWEB)

    Ibsen, Lars Bo; Liingaard, M.; Andersen, Lars

    2006-12-15

    The dynamic response of offshore wind turbines are affected by the properties of the foundation and the subsoil. The purpose of this report is to evaluate the dynamic soil-structure interaction of suction caissons for offshore wind turbines. The investigation is limited to a determination of the vertical dynamic stiffness of suction caissons. The soil surrounding the foundation is homogenous with linear viscoelastic properties. The dynamic stiffness of the suction caisson is expressed by dimensionless frequency-dependent dynamic stiffness coefficients corresponding to the vertical degree of freedom. The dynamic stiffness coefficients for the foundations are evaluated by means of a dynamic three-dimensional coupled Boundary Element/Finite Element model. Comparisons are made with known analytical and numerical solutions in order to evaluate the static and dynamic behaviour of the Boundary Element/Finite Element model. The vertical frequency dependent stiffness has been determined for different combinations of the skirt length, Poisson's ratio and the ratio between soil stiffness and skirt stiffness. Finally the dynamic behaviour at high frequencies is investigated. (au)

  11. Numerical Method for Wave Forces Acting on Partially Perforated Caisson

    Institute of Scientific and Technical Information of China (English)

    姜峰; 唐晓成; 金钊; 张莉; 陈洪洲

    2015-01-01

    The perforated caisson is widely applied to practical engineering because of its great advantages in effectively wave energy consumption and cost reduction. The attentions of many scientists were paid to the fluid–structure interaction between wave and perforated caisson studies, but until now, most concerns have been put on theoretical analysis and experimental model set up. In this paper, interaction between the wave and the partial perforated caisson in a 2D numerical wave flume is investigated by means of the renewed SPH algorithm, and the mathematical equations are in the form of SPH numerical approximation based on Navier–Stokes equations. The validity of the SPH mathematical method is examined and the simulated results are compared with the results of theoretical models, meanwhile the complex hydrodynamic characteristics when the water particles flow in or out of a wave absorbing chamber are analyzed and the wave pressure distribution of the perforated caisson is also addressed here. The relationship between the ratio of total horizontal force acting on caisson under regular waves and its influence factors is examined. The data show that the numerical calculation of the ratio of total horizontal force meets the empirical regression equation very well. The simulations of SPH about the wave nonlinearity and breaking are briefly depicted in the paper, suggesting that the advantages and great potentiality of the SPH method is significant compared with traditional methods.

  12. Vibration mechanism research of large-scale and deep-water caisson

    Institute of Scientific and Technical Information of China (English)

    Yin Haihua; Han Jingjing

    2011-01-01

    According to the construction method of Taizhou Bridge, numerical simulation is conducted to analyze the vibration of caisson under wind and water flows to determine the main factors of the caisson vibration. Meanwhile, the localization system of caissons and anchors of Taizhou Bridge is modeled in order to summarize the vibration mechanism of caissons under deep-water and jet-flow condition, and further pertinent vibration-control measures are proposed. The obtained results are well verified in engineering practice, and consequently the safety risk of positioning the caisson is reduced.

  13. Apparatus for ground water chemistry investigations in field caissons

    Energy Technology Data Exchange (ETDEWEB)

    Cokal, E.J.; Stallings, E.; Walker, R.; Nyhan, J.W.; Polzer, W.L.; Essington, E.H.

    1985-01-01

    Los Alamos is currently in its second season of ground water chemistry and hydrology experimentation in a field facility that incorporates clusters of six, 3-meter-diameter by 6-meter-deep, soil-filled caissons and required ancillaries. Initial experience gained during the 1983 field season indicated the need for further development of the technology of this type of experimentation supporting hydrologic waste management research. Uniform field application of water/matrix solutions to the caisson, matrix and tracer solution blending/storage, and devices for ground water sampling are discussed.

  14. Computer tomography in Caisson's disease

    Energy Technology Data Exchange (ETDEWEB)

    Horvath, F.; Csobaly, S.

    1981-07-01

    Computer tomography was performed on 20 patients with the early stages of Caisson osteoarthropathy, as well as in other patients with chronic bone infarcts. From their results the authors have formed the opinion that CT is valuable, not only in the diagnosis of early cases, but that it can provide significant information concerning the osteopathy and bone infarcts.

  15. Results of Caisson Breakwater Tests in Multidirectional Breaking Seas

    DEFF Research Database (Denmark)

    Kofoed, Jens Peter

    In extension of the work done at the Hydraulics and Coastal Engineering Laboratory, Dept. of Civil Engineering, Aalborg University, Denmark, described in Grønbech et al., 1997, laboratory tests has been performed investigating wave loading and overtopping on caisson breakwaters in multidirectional...

  16. Vibrating-Rocking Motion of Caisson Breakwater Under Breaking Wave Impact

    Institute of Scientific and Technical Information of China (English)

    王元战; 郑斌

    2001-01-01

    The possible motions of a caisson breakwater under dynamic load excitation include vibrating, vibrating-sliding andvibrating-rocking motions. The models of vibrating motion and vibrating-sliding motion have been proposed in an earlypaper. In this paper, a model of vibrating-rocking motion of caisson breakwaters under breaking wave impact is presented, which can be used to simulate the histories of vibrating-rocking motion of caisson breakwaters. The effect of rocking motion on the displacement, rotation, sliding force and overturning moment of breakwaters is investigated. In casethe overturning moment exceeds the stability moment ofa caisson, the caisson may only rock. The caisson overturns only in case the rocking angle exceeds the critical angle. It is shown that the sliding force and overturning moment of break-waters can be reduced effectively due to the rocking motion. It is proposed that some rocking motion should be allowedin breakwater design.

  17. Technical research on control of caisson construction for the middle tower foundation of Taizhou Bridge

    Institute of Scientific and Technical Information of China (English)

    Liu Jianbo; Yang Yanhua; Zhang Yongtao; Du Song

    2011-01-01

    The real-time informational monitoring system is adopted in the construction of middle tower foundation of Taizhou Bridge for the first time. The geometric state of the caisson, the stress of upstream and downstream anchorage cables, underwater topography, the drag forces of the caisson cutting edge and frictional resistances of the sidewall and etc. are monitored in real time. According to the synthesized data analysis and decision-making system, the spatial states of the caisson are adjusted in time to locate and embed the deep water caisson precisely. The offset error of the caisson is less than 30 cm and the vertical error is 1/363 at the final stage. The control technology for construction of large caisson under deep water is concluded and would be helpful for the construction of bridge foundation in the future.

  18. Vibrating-Sliding Motion of Caisson Breakwaters Under Various Breaking Wave Impact Forces

    Institute of Scientific and Technical Information of China (English)

    王元战; 于红霞

    2003-01-01

    Sliding is one of the principal failure types of caisson breakwaters and is an essential content of stability examination in caisson breakwater design. Herein, the mass-spring-dashpot model of caisson-base system is used to simulate the vibrating-sliding motion of the caisson under various types of breaking wave impact forces, i.e., single peak impact force, double peak impact force, and shock-damping oscillation impact force. The effects of various breaking wave impacts and the sliding motion on the dynamic response behaviors of caisson breakwaters are investigated and the calculation of relevant system parameters is discussed. It is shown that the dynamic responses of the caisson are significantly different under different types of breaking wave impact forces even when the amplitudes of impact forces are equal. The amplitude of dynamic response of the caisson is lower under single peak impact excitation than that under double peak impact or shock-damping oscillation impact excitation. Though the displacement of the caisson is large due to sliding, the rotation, the sliding force and the overturning moment of the caisson are significantly reduced.

  19. VIBRATING-UPLIFT ROCKING MOTION OF CAISSON BREAKWATERS UNDER VARIOUS BREAKING WAVE IMPACT FORCES

    Institute of Scientific and Technical Information of China (English)

    WANG Yuan-zhan; ZHOU Zhi-rong; YANG Hai-dong

    2005-01-01

    Overturning is one of principal failure types of caisson breakwaters and is an essential content of stability examination in caisson breakwater design. The mass-springdashpot model of caisson-foundation system is used to simulate the vibrating-uplift rocking motion of caisson under various types of breaking wave impact forces, i.e., single peak impact force, double peak impact force, and shock-damping oscillation impact force. The effects of various breaking wave types and the uplift rocking motion on dynamic response behaviors of caisson breakwaters are investigated. It is shown that the dynamic responses of a caisson are significantly different under different types of breaking wave impact forces even when the amplitudes of impact forces are equal. Though the rotation of a caisson is larger due to the uplift rocking motion, the displacement, the sliding force and the overturning moment of the caisson are significantly reduced. It provides the theoretical base for the design idea that the uplift rocking motion of caisson is allowed in design.

  20. Reliability Index of Caisson Breakwaters for Load Variables Correlated

    Institute of Scientific and Technical Information of China (English)

    郄禄文; 李炎保

    2004-01-01

    In order to suit the condition that the wave uplift is correlated with the horizontal wave load acting on a vertical breakwater, a generally used method for determining the reliability index β of the breakwater, i.e. the Hasofer-Lind method, is extended in a generalized stochastic space for correlative variables. The computational results for a caisson breakwater indicate that the value of β for the case of correlated variables is obviously smaller than that for the case of independent variables.

  1. 3-D Effects Force Reduction of Short-Crested Non-Breaking Waves on Caissons

    DEFF Research Database (Denmark)

    Burcharth, H. F.; Liu, Z.

    1998-01-01

    The effect of wave short-crestedness on the horizontal wave force on a caisson is twofold. The one is the force reduction due to the reduction of point pressure on the caisson, named point-pressure reduction. The other is the force reduction due to the fact that the peak pressures do not occur si...

  2. REFLECTION OF OBLIQUE INCIDENT WAVES BY PERFORATED CAISSONS WITH TRAVERSE WALL

    Institute of Scientific and Technical Information of China (English)

    LI Yu-cheng; LIU Hong-jie; DONG Guo-hai

    2005-01-01

    The interaction of oblique incident waves with infinite number of perforated caissons is investigated. The fluid domain is divided into infinite sub-domains by the caissons, and eigen-function expansion is applied to expand velocity potentials in each domain. A phase relation is introduced for wave oscillation in each caisson, and the structure geometry is considered in constructing the models of reflection waves. The reflected waves with the present analysis include all of the waves traveling in different directions when incident wave period is short. Numerical examinations show that velocities at the inner and outer sides of the front walls of caissons are close to each other, and reflection coefficients satisfy the energy conservation relation very well when porous effect parameter is infinite. Numerical results show that the reflection coefficients of oblique incident waves are smaller for shorter caissons at low frequency, and decrease with the increase of wave incident angle.

  3. Modelling of Performance of Caisson Type Breakwaters under Extreme Waves

    Science.gov (United States)

    Güney Doǧan, Gözde; Özyurt Tarakcıoǧlu, Gülizar; Baykal, Cüneyt

    2016-04-01

    Many coastal structures are designed without considering loads of tsunami-like waves or long waves although they are constructed in areas prone to encounter these waves. Performance of caisson type breakwaters under extreme swells is tested in Middle East Technical University (METU) Coastal and Ocean Engineering Laboratory. This paper presents the comparison of pressure measurements taken along the surface of caisson type breakwaters and obtained from numerical modelling of them using IH2VOF as well as damage behavior of the breakwater under the same extreme swells tested in a wave flume at METU. Experiments are conducted in the 1.5 m wide wave flume, which is divided into two parallel sections (0.74 m wide each). A piston type of wave maker is used to generate the long wave conditions located at one end of the wave basin. Water depth is determined as 0.4m and kept constant during the experiments. A caisson type breakwater is constructed to one side of the divided flume. The model scale, based on the Froude similitude law, is chosen as 1:50. 7 different wave conditions are applied in the tests as the wave period ranging from 14.6 s to 34.7 s, wave heights from 3.5 m to 7.5 m and steepness from 0.002 to 0.015 in prototype scale. The design wave parameters for the breakwater were 5m wave height and 9.5s wave period in prototype. To determine the damage of the breakwater which were designed according to this wave but tested under swell waves, video and photo analysis as well as breakwater profile measurements before and after each test are performed. Further investigations are carried out about the acting wave forces on the concrete blocks of the caisson structures via pressure measurements on the surfaces of these structures where the structures are fixed to the channel bottom minimizing. Finally, these pressure measurements will be compared with the results obtained from the numerical study using IH2VOF which is one of the RANS models that can be applied to simulate

  4. Dynamic stiffness of suction caissons - torsion, sliding and rocking

    Energy Technology Data Exchange (ETDEWEB)

    Ibsen, Lars Bo; Liingaard, M.; Andersen, Lars

    2006-12-15

    This report concerns the dynamic soil-structure interaction of steel suction caissons applied as foundations for offshore wind turbines. An emphasis is put on torsional vibrations and coupled sliding/rocking motion, and the influence of the foundation geometry and the properties of the surrounding soil is examined. The soil is simplified as a homogenous linear viscoelastic material and the dynamic stiffness of the suction caisson is expressed in terms of dimensionless frequency-dependent coefficients corresponding to the different degrees of freedom. The dynamic stiffness coefficients for the skirted foundation are evaluated by means of a three-dimensional coupled boundary element/finite element model. Comparisons with known analytical and numerical solutions indicate that the static and dynamic behaviour of the foundation are predicted accurately with the applied model. The analysis has been carried out for different combinations of the skirt length and the Poisson's ratio of the subsoil. Finally, the high-frequency impedance has been determined for future use in lumped-parameter models of wind turbine foundations in aero-elastic codes. (au)

  5. Numerical analysis on bearing capacity of middle pylon caisson foundation of Taizhou Bridge

    Institute of Scientific and Technical Information of China (English)

    Wang Jun; Shao Guojian; Hu Feng; Gu Lijun

    2012-01-01

    Because of the computation difficulty of the beating capacity of large underwater caisson foundation on thick overburden layer ground, the geotechnieal software FLAC3D was utilized in the 3D numerical analysis on the bearing capacity of middle pylon foundation. From the computational results, it is concluded that the caisson foundation has a good bearing capacity on thick overburden layer ground and the beating capacity can be improved assuming that the soil near the area of basal comer is reinforced.

  6. Finite Element Analysis of Laterally Loaded Suction Caisson in Anisotropic Clay

    Institute of Scientific and Technical Information of China (English)

    WANG Dong; JIN Xia

    2006-01-01

    Naturally deposited clay is usually characterized by strength anisotropy; however, the effect of anisotropy on the capacity of a suction caisson was seldom investigated. The conventional Hill yield surface includes undrained strengths in triaxial shear, simple shear and pressuremeter shear simultaneously but it can not specify differences in respect to the mode of loading for a given shearing mode. A new technique of updating strength is integrated into incremental finite element (FE) calculation to consider the mode of loading, which is applied to the study of variation of capacity with the aspect ratio of suction caissons in anisotropic clay. Compared with the upper bound limit analysis, FE simulation is capable of offering the lateral capacity of short caissons. In the normal range of anisotropic strength properties, the Mises yield surface with simple shear strength predicts the horizontal capacity of which the error is less than 10% for rough caissons and 15% for smooth caissons. It is also found that the friction of caisson affects the capacity significantly.

  7. A Probabilistic Method for Motion Analysis of Caisson Breakwaters

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    It is assumed that, during the design period, the waves acting on breakwaters are divided into three types: standing wave, broken wave and breaking wave,and the wave heights fit the Rayleigh distribution while the water depths, wave periods and duration of breaking wave impact force fit normal distribution. Based on the random samples of water depths, wave heights, wave periods and duration of breaking wave impact force, the types of waves acting on breakwaters are distinguished and the time-history model of the wave force is determined. The motions of caisson breakwaters under the wave force are simulated by a dynamic numerical model and the statistic characteristics of the dynamic responses are analyzed with the Monte Carlo method. A probabilistic procedure to analyze the motion of the breakwater is developed therein. The procedure is illustrated by an example.

  8. Dynamic Stability Analysis of Caisson Breakwater in Lifetime Considering the Annual Frequency of Severe Storm

    Institute of Scientific and Technical Information of China (English)

    王禹迟; 王元战; 洪宁宁

    2015-01-01

    In the dynamic stability analysis of a caisson breakwater, most of current studies pay attention to the motion characteristics of caisson breakwaters under a single periodical breaking wave excitation. And in the lifetime stability analysis of caisson breakwater, it is assumed that the caisson breakwater suffers storm wave excitation once annually in the design lifetime. However, the number of annual severe storm occurrence is a random variable. In this paper, a series of random waves are generated by the Wen Sheng-chang wave spectrum, and the histories of successive and long-term random wave forces are built up by using the improved Goda wave force model. It is assumed that the number of annual severe storm occurrence is in the Poisson distribution over the 50-year design lifetime, and the history of random wave excitation is generated for each storm by the wave spectrum. The response histories of the caisson breakwater to the random waves over 50-year design lifetime are calculated and taken as a set of samples. On the basis of the Monte Carlo simulation technique, a large number of samples can be obtained, and the probability assessment of the safety of the breakwater during the complete design lifetime is obtained by statistical analysis of a large number of samples. Finally, the procedure of probability assessment of the breakwater safety is illustrated by an example.

  9. Dynamic model of vibrating-sliding-uplift rocking coupled motion and dynamic design method of caisson breakwaters

    Institute of Scientific and Technical Information of China (English)

    WANG; Yuanzhan; HUA; Leina; DONG; Shaowei

    2004-01-01

    Vibrating, sliding and uplift rocking are three elementary motion types of caisson breakwaters. The dynamic model and the numerical simulation method of vibrating-sliding-uplift rocking coupled motion of caisson breakwaters are developed. The histories of displacement, rotation, sliding force and overturning moment of a caisson breakwater under the excitation of breaking wave impact are calculated for the motion models of vibrating, vibrating-sliding, vibrating-uplift rocking and vibrating-sliding-uplift rocking. The effects of various motion models on the stability of caisson breakwaters are investigated. The feasibility of the dynamic design idea that the sliding motion and the uplift rocking motion of caisson breakwaters are allowed under the excitation of breaking wave impact is discussed.

  10. Numerical Buckling Analysis of Large Suction Caissons for Wind Turbines on Deep Water

    DEFF Research Database (Denmark)

    Madsen, Søren; Andersen, Lars Vabbersgaard; Ibsen, Lars Bo

    2013-01-01

    the suction caisson is loaded by external pressure (internal suction) due to evacuation of water inside the bucket and vertical forces due to gravity. The risk of structural buckling during installation of large-diameter suction caissons is addressed using numerical methods. Initial imperfect geometries...... are introduced, based on the buckling mode shapes from a linear eigenvalue buckling analysis. Different imperfect geometries are introduced to reveal how sensitive the buckling load is to these imperfections. Including the first 21 mode shapes as imperfect geometries will reduce the buckling pressure compared...... to only considering mode 1. The results of the finite element analysis are compared with current standards for evaluating buckling loads....

  11. Caisson Movement Caused by Wave Slamming—a Comparison of ABAQUS and FLAC Analyses

    DEFF Research Database (Denmark)

    Andersen, Lars; Burcharth, Hans F.; Andersen, Thomas Lykke;

    2010-01-01

    During wave slamming, caisson movement may occur as a combination of sliding along the caisson–foundation interface and local failure in the foundation and seabed. The paper presents a comparison between different techniques applied to the analysis of this movement. Thus, a finite-difference anal......During wave slamming, caisson movement may occur as a combination of sliding along the caisson–foundation interface and local failure in the foundation and seabed. The paper presents a comparison between different techniques applied to the analysis of this movement. Thus, a finite...

  12. Large Scale Experiments on the Interaction of a Caisson Breakwater with Breaking Waves

    DEFF Research Database (Denmark)

    Stagonas, Dimitris; Marzeddu, Andrea; Buccino, Mariano;

    2014-01-01

    Tests looking at the interaction of a caisson breakwater with steep, breaking waves are outlined here. 4 different wave generation methodologies were employed allowing for experiments with regular, irregular, focused and tailored made waves. The emphasis, however, is given in tests with focused...... waves, which resulted in impulsive conditions at the face of the caisson. Amongst our objectives was to look at the mechanisms occurring when a wave breaks at the structure and to investigate the validity of tactile pressure sensors. As such, for all experiments, pressure, force and surface elevation...

  13. Numerical Simulation of Nonlinear Wave Force on a Quasi-ellipse Caisson

    Institute of Scientific and Technical Information of China (English)

    Yongxue Wang; Xiaozhong Ren; Guoyu Wang

    2011-01-01

    A three dimensional numerical model of nonlinear wave action on a quasi-ellipse caisson in a time domain was developed in this paper.Navier-Stokes equations were solved by the finite difference method,and the volume of fluid (VOF) method was employed to trace the free surface.The partial cell method was used to deal with the irregular boundary typical of this type of problem during first-time wave interaction with the structure,and a satisfactory result was obtained.The numerical model was verified and used to investigate the effects of the relative wave height H/d,relative caisson width kD,and relative length-width ratio B/D on the wave forces of the quasi-ellipse caisson.It was shown that the relative wave height H/d has a significant effect on the wave forces of the caisson.Compared with the non-dimensional inline wave force,the relative length-width ratio B/D was shown to have significant influence on the non-dimensional transverse wave force.

  14. Three-Dimensional Model Test Study of Modified Caisson Breakwater at Port of Castellon, Spain

    DEFF Research Database (Denmark)

    Nørgaard, Jørgen Harck; Andersen, Thomas Lykke

    caisson breakwater at Port of Castellon, Spain, tested earlier (Nørgaard & Lykke Andersen, 2013). Associate Prof. Thomas Lykke Andersen and M.Sc. Jørgen Quvang Harck Nørgaard were in charge of the model tests. Engineer assistant Niels Drustrup assisted in the laboratory with the construction...

  15. Long term effects of cyclic loading on suction caisson foundations in sand

    NARCIS (Netherlands)

    Lupea, C.; Thijssen, R.; Van Tol, A.F.

    2014-01-01

    Offshore wind turbine projects have been characterised by an increase in costs, sizes and distances from shore, EWEA 2012 This created a need of investigating the adequacy of alternative and more fìnancially attractive foundation types such as suction caissons. Within a multi-footing configuration,

  16. Present knowledge about Laboratory Testing of Axial Loading on Suction Caissons

    DEFF Research Database (Denmark)

    Manzotti, E.; Vaitkunaite, Evelina; Ibsen, Lars Bo

    on the structure is resisted by push-pull loads on the vertical axis of each suction caisson. Relevant works where this situation is examined by means of laboratory testing are summarized in this article, then different conclusions are followed by discussion and comparison. In the initial theoretical section...

  17. Analyses of Stability of Caisson Breakwaters on Rubble Foundation Exposed to Impulsive Loads

    DEFF Research Database (Denmark)

    Burcharth, Hans F.; Andersen, Lars; Andersen, Thomas Lykke

    2009-01-01

    The paper deals with the analysis of the overall stability of caisson breakwaters exposed to impulsive wave loadings, in particular regarding sliding failure and failure in the subsoil. A comparison is made between prediction of sliding distances by a simple onedimensional (1-D) dynamic analysis...

  18. Risk Analysis of Breakwater Caisson Under Wave Attack Using Load Surface Approximation

    Institute of Scientific and Technical Information of China (English)

    Dong Hyawn KIM

    2014-01-01

    A new load surface based approach to the reliability analysis of caisson-type breakwater is proposed. Uncertainties of the horizontal and vertical wave loads acting on breakwater are considered by using the so-called load surfaces, which can be estimated as functions of wave height, water level, and so on. Then, the first-order reliability method (FORM) can be applied to determine the probability of failure under the wave action. In this way, the reliability analysis of breakwaters with uncertainties both in wave height and in water level is possible. Moreover, the uncertainty in wave breaking can be taken into account by considering a random variable for wave height ratio which relates the significant wave height to the maximum wave height. The proposed approach is applied numerically to the reliability analysis of caisson breakwater under wave attack that may undergo partial or full wave breaking.

  19. Seismic response of bridge pier on rigid caisson foundation in soil stratum

    Institute of Scientific and Technical Information of China (English)

    C. Tsigginos; N. Gerolymos; D. Assimaki; G. Gazetas

    2008-01-01

    An analytical method to study the seismic response of a bridge pier supported on a rigid caisson foundation embedded in a deep soil stratum underlain by a homogeneous half space is developed. The method reproduces the kinematic and inertial responses, using translational and rotational distributed Winkler springs and dashpots to simulate the soil-caisson interaction. Closed-form solutions are given in the frequency domain for vertical harmonic S-wave excitation. Comparison with results from finite element (FE) analysis and other available solutions demonstrates the reliability of the model. Results from parametric studies are given for the kinematic and inertial responses. The modification of the fundamental period and damping ratio of the bridge due to soil-structure interaction is graphically illustrated.

  20. Prediction Method of Seismic Residual Deformation of Caisson Quay Wall in Liquefied Foundation

    Institute of Scientific and Technical Information of China (English)

    WANG Li-yan; LIU Han-long; JIANG Peng-ming; CHEN Xiang-xiang

    2011-01-01

    The multi-spring shear mechanism plastic model in this paper is defined in strain space to simulate pore pressure generation and development in sands under cyclic loading and undrained conditions,and the rotation of principal stresses can also be simulated by the model with cyclic behavior of anisotropic consolidated sands.Seismic residual deformations of typical caisson quay walls under different engineering situations are analyzed in detail by the plastic model,and then an index of liquefaction extent is applied to describe the regularity of seismic residual deformation of caisson quay wall top under different engineering situations.Some correlated prediction formulas are derived from the results of regression analysis between seismic residual deformation of quay wall top and extent of liquefaction in the relative safety backfill sand site.Finally,the rationality and the reliability of the prediction methods are validated by test results of a 120 g-centrifuge shaking table,and the comparisons show that some reliable seismic residual deformation of caisson quay can be predicted by appropriate prediction formulas and appropriate index of liquefaction extent.

  1. Chapter 4: Pulsating Wave Loads Section 4.3: 3D Effects Force Reduction of Short-Crested Non-Breaking Waves on Caissons

    DEFF Research Database (Denmark)

    Burcharth, Hans F.; Liu, Zhou

    1999-01-01

    The effect of wave short-crestedness on the horizontal wave force on a caisson is twofold. The one is the force reduction due to the reduction of point pressure on the caisson, named point-pressure reduction. The other is the force reduction due to the fact that the peak pressures do not occur si...

  2. A Study of the system control model of caisson dewatering of the north anchorage of Taizhou Bridge

    Institute of Scientific and Technical Information of China (English)

    Zhao Yanrong; Zhou Zhifang; Ruan Jing

    2011-01-01

    A caisson foundation is applied to the north anchorage of Taizhou Yangtze River Highway Bridge of which the initial caisson sinking requires dewatering. Since the caisson foundation is quite close to nearby buildings, a system control model is established with source (sink) distribution and intensity being the object function, minimum requirements of settlement and deformation of surroundings caused by dewatering and dynamic water levels during different working procedures being constraints, and the design parameter of pumping wells being the variable, so as to lower the jeopardizing of surrounding buildings, which provides a new method for active control over settlement during dewatering. Such a method of dewatering based on system control model should be of significance for similar projects involving dewatering.

  3. Theoretical Investigation of Peak-Delay Force Reduction for Caissons Exposed to Non-breaking Short-Crested Waves

    DEFF Research Database (Denmark)

    Burcharth, H. F.; Liu, Z.

    In nature coastal structures are exposed to oblique short-crested waves. The effect of wave incident angle on total wave force on a long caisson are twofold. The one is the force reduction due to the reduction of instantaneous point pressure on the caisson, named point-pressure force reduction...... on the peak-delay force reduction of caissons exposed to non-breaking short-crested waves. Battjes (1982) has investigated theoretically the peak-delay force reduction of shortcrested waves with only one frequency component. Such a force reduction factor cannot be applied because in nature waves are composed...... of many linear components with various frequencies. In this paper the peak-delay force reduction factor is defined on basis of zero-moment of the force spectrum. Based on linear wave theory, formulae for calculation of peakdelay force reduction factor for linear, long-crested and short-crested non-breaking...

  4. Three-dimensional mathematical model of river bed erosion by float open caisson in construction period

    Institute of Scientific and Technical Information of China (English)

    方红卫

    1995-01-01

    The basic governing equations and boundary conditions are deduced in general curve coordination system from natural variable-density turbulence which is two-phase flow with sediment. A new 27-point three-dimensional finite analytic discretization scheme and competent velocity formula for non-uniform bed material are applied to the calculation of the float open caisson in construction period. It is shown that good accuracy and adaptation are obtained in the calculation of two-phase flow with sediment and variable-density as well as complex boundary.

  5. Barodontalgias, dental and orofacial barotraumas: a survey in Swiss divers and caisson workers.

    Science.gov (United States)

    Zanotta, Cristina; Dagassan-Berndt, Dorothea; Nussberger, Peter; Waltimo, Tuomas; Filippi, Andreas

    2014-01-01

    Changing ambient pressure can lead to medical conditions in body cavities filled with air. Intraoral pain elicited by changes in pressure is referred to as barodontalgia. Dental barotraumas are defined as pressure-induced damages of teeth and restorations. The pathophysiologic background so far is not completely clear. The present study deals with dental and orofacial symptoms which can occur as a result of pressure variations. With the aid of cantonal administrations, diving associations, and tunnel construction firms, 520 pressure-exposed individuals (499 scuba/ professional divers, 21 caisson workers operating at excess pressure) were questioned regarding dental problems. A personal interview was conducted with affected individuals. Problems in the dental area were experienced by 15% of all respondents. Toothaches were suffered by 10.2% of the participants. Tooth injuries occurred in 6.3% of all interviewees (26 fractured amalgam restorations, 4 crown fractures, 3 losses of tooth fragments). A proportion of 11.3% among the respondents complained about temporomandibular joint problems or mucosal irritations (for example aphthae) related to the mouthpieces. Barotraumas outside the dental area were incurred by 31.9% of the divers. Of these, 69.9% concerned the ears and 65.6% occurred during the descent. Based on the results obtained from the survey and taking into account the current literature, recommendations for the prevention of barotraumas in divers and caisson workers were prepared. Diagnostic exclusion of dental pathologies and avoidance of retentive reconstruction materials are important factors for the prevention of barodontalgias and dental barotraumas.

  6. Effect of Short-Crestedness and Obliquity on Non-Breaking and Breaking Wave Forces Applied to Vertical Caisson Breakwaters

    DEFF Research Database (Denmark)

    Martinelli, Luca; Lamberti, Alberto; Frigaard, Peter

    2007-01-01

    This paper addresses wave forces applied to vertical caisson breakwaters. Design diagrams are proposed to evaluate the reduction of the breaker wave force with increasing horizontal length of the units. A model in 1:100 scale of a typical Italian vertical breakwater was tested under multidirectio...

  7. Alternative Shape of Suction Caisson to Reduce Risk of Buckling under high Pressure

    DEFF Research Database (Denmark)

    Madsen, Søren; Andersen, Lars Vabbersgaard; Ibsen, Lars Bo

    2013-01-01

    by uniform external pressure and vertical forces. The bucket foundation does not require heavy installation equipment, but since it is constructed as a thin steel shell structure, instability, in the form of buckling, becomes a crucial issue during installation. Typically, the bucket foundation is a large...... cylindrical monopod foundation made of steel. In this paper, an alternative design/shape of the suction caisson, having a smaller risk of buckling under high pressure is presented. The risk of structural buckling is addressed using numerical methods to determine the buckling pressures of the re......-designed bucket foundation during installation. Further, the effect of the lateral restraint offered by the surrounding soil on the buckling pressures is analysed. It is found that the new design enables a significantly larger buckling load compared to the traditional design....

  8. Experimental and Theoretical Investigation of Wave Forces on A Partially-Perforated Caisson Breakwater with A Rock-Filled Core

    Institute of Scientific and Technical Information of China (English)

    LIU Yong; LI Yu-cheng; TENG Bin; JIANG Jun-jie

    2006-01-01

    The total horizontal and vertical forces acting on a partially-perforated caisson breakwater and their phase difference are investigated in this study. The perforated breakwater sits on the rubble filled foundation, and has a rock-filled core. An analytical solution is developed based on the eigenfunction expansion and matching method to solve the wave field around the breakwater. The finite element method is used for simulating the wave-induced flow in the rubble-filled foundation. Experiments are also conducted to study the wave forces on the perforated caissons. Numerical predictions of the present model are compared with experimental results. The phase differences between the total horizontal and vertical forces are particularly analyzed by means of experimental and numerical results. The major factors that affect the wave forces are examined.

  9. Consolidation and dynamics of 3D unsaturated porous seabed under rigid caisson breakwater loaded by hydrostatic pressure and wave

    Institute of Scientific and Technical Information of China (English)

    YE JianHong; JENG DongSheng; CHAN A H C

    2012-01-01

    In this study,based on the dynamic Biot's theory "u-p" approximation,a 3D finite element method (FEM) numerical soil model is developed,in which the Generalized Newmark-β method is adopted to determine the time integration.The developed 3D FEM soil model is a part of the coupled model PORO-WSSI 3D for 3D wave-seabed-marine structures interaction problem,and is validated by the analytical solution proposed by Wang (2000) for a laterally infinite seabed loaded by a uniform force.By adopting the developed 3D soil model,the consolidation of seabed under a caisson breakwater and hydrostatic pressure is investigated.The numerical results show that the caisson breakwater built on seabed has very significant effect on the stresses/displacements fields in the seabed foundation after the transient deformation and primary consolidation are completed.The parametric study indicates that the Young's modulus E of seabed is the most important parameter to affect the settlement of breakwater,and the displacement fields in seabed foundation.Taking the consolidation status as the initial condition,the interaction between ocean wave,caisson breakwater and seabed foundation is briefly investigated.The 3D ocean wave is determined by solving the Navier-Stokes equations with finite volume method (FVM).The numerical results indicate that there is intensive interaction between ocean wave,caisson breakwater and seabed foundation; and the breakwater indeed can effectively block the wave energy propagating to the coastline.

  10. Numerical analyses of caisson breakwaters on soft foundations under wave cyclic loading

    Science.gov (United States)

    Wang, Yuan-zhan; Yan, Zhen; Wang, Yu-chi

    2016-03-01

    A caisson breakwater is built on soft foundations after replacing the upper soft layer with sand. This paper presents a dynamic finite element method to investigate the strength degradation and associated pore pressure development of the intercalated soft layer under wave cyclic loading. By combining the undrained shear strength with the empirical formula of overconsolidation clay produced by unloading and the development model of pore pressure, the dynamic degradation law that describes the undrained shear strength as a function of cycle number and stress level is derived. Based on the proposed dynamic degradation law and M-C yield criterion, a dynamic finite element method is numerically implemented to predict changes in undrained shear strength of the intercalated soft layer by using the general-purpose FEM software ABAQUS, and the accuracy of the method is verified. The effects of cycle number and amplitude of the wave force on the degradation of the undrained shear strength of the intercalated soft layer and the associated excess pore pressure response are investigated by analyzing an overall distribution and three typical sections underneath the breakwater. By comparing the undrained shear strength distributions obtained by the static method and the quasi-static method with the undrained shear strength distributions obtained by the dynamic finite element method in the three typical sections, the superiority of the dynamic finite element method in predicting changes in undrained shear strength is demonstrated.

  11. Numerical Analyses of Caisson Breakwaters on Soft Foundations Under Wave Cyclic Loading

    Institute of Scientific and Technical Information of China (English)

    王元战; 焉振; 王禹迟

    2016-01-01

    A caisson breakwater is built on soft foundations after replacing the upper soft layer with sand. This paper presents a dynamic finite element method to investigate the strength degradation and associated pore pressure development of the intercalated soft layer under wave cyclic loading. By combining the undrained shear strength with the empirical formula of overconsolidation clay produced by unloading and the development model of pore pressure, the dynamic degradation law that describes the undrained shear strength as a function of cycle number and stress level is derived. Based on the proposed dynamic degradation law and M-C yield criterion, a dynamic finite element method is numerically implemented to predict changes in undrained shear strength of the intercalated soft layer by using the general-purpose FEM software ABAQUS, and the accuracy of the method is verified. The effects of cycle number and amplitude of the wave force on the degradation of the undrained shear strength of the intercalated soft layer and the associated excess pore pressure response are investigated by analyzing an overall distribution and three typical sections underneath the breakwater. By comparing the undrained shear strength distributions obtained by the static method and the quasi-static method with the undrained shear strength distributions obtained by the dynamic finite element method in the three typical sections, the superiority of the dynamic finite element method in predicting changes in undrained shear strength is demonstrated.

  12. Special Foundation by means of reinforced-concrete caisson in Valencia Port; Cimentaciones especiales de los cajones del Muello Este. Puerto de Valencia

    Energy Technology Data Exchange (ETDEWEB)

    Gama Costa, P. M.

    2010-07-01

    This paper describes the process to construct a foundation by means of reinforced-concrete caisson on breakwaters. the project required to develop minimal dredging solutions as well as to improve the foundation areas of the what caissons. The improvement technique applied to the foundation area was based on gravel columns, since this solution was the most suitable for areas with high fine fraction contents, as it was the case. Gravel columns were executed following a bottom-feed method, and two different techniques: gravel tank top-feeding and gravel pumping. (Author)

  13. Reflection of regular and irregular waves from a partially perforated caisson breakwater with a rock-filled core

    Institute of Scientific and Technical Information of China (English)

    LIU Yong; LI Yucheng; TENG Bin; MA Baolian

    2007-01-01

    The reflection of regular and irregular waves from a partially perforated caisson breakwater with a rock-filled core is examined. The present mathematical model is developed by means of the matched eigenfunction method. Numerical results of the present model are compared with the experimental data of different researchers. Numerical examples are given to examine the effect of rock fill on the reflection coefficient. The differences between regular and irregular waves are also investigated by means of theoretical and experimental results. It is found that the minimum reflection coefficient of irregular waves is larger than that of corresponding regular waves, but the contrary is the case for the maximum reflection coefficient.

  14. On-site tests to estimate aquifer permeability of drainage area of south caisson anchorage construction of Taizhou Bridge

    Institute of Scientific and Technical Information of China (English)

    Feng Zhaoxiang; Zhao Yanrong

    2011-01-01

    During the construction of the south caisson anchorage of Taizhou Bridge, the drainage area is located in the lower reaches of the Yangtze River and the permeability of stratums there is considerable. In order to maintain progress and guarantee safety during the sinking of the caisson, water should be drained in the initial period. Subsequently, detailed information about the aquifer permeability is required to make sure that the drainage will proceed successfully,which consequently necessitates the on-site estimation of the aquifer permeability in the drainage area. Therefore, the traditional pumping test and slug test are implemented respectively on site. The comparison of computational results of these two tests indicates that they are consistent overall. Notwithstanding, as slug test can be conducted with portable facilities in a short time and the manipulation is easy and few people need to be involved, the advantages of slug test is conspicuous compared with the traditional pumping test. It could be speculated that slug test will gain a prevalent application in the measurement of aquifer permeability in the future.

  15. Main points for design and construction in formwork of caisson type dock gate%坞门式沉箱模板设计及施工要点

    Institute of Scientific and Technical Information of China (English)

    黄文慧; 董政

    2015-01-01

    Caisson type dock gate is an important part of the immersed tunnel precast yard. Its size is 59 m×25.2 m×29.1 m. Although the construction of caisson is very common in hydraulic industry, the construction of large-scale caisson in need of floating transportation has its characteristics. Starting with the design and construction in formwork of large-scale caisson type dock gate, which is in the immersed tube prefabricated factory of the Hongkong-Zhuhai-Macao Bridge, we discussed some parts which in need of particular attention to. The beneficial experiences are obtained.%沉箱结构的坞门在沉管隧道预制场中是重要的构件,其尺寸达到了59 m ×25.2 m ×29.1 m。虽然沉箱施工在水工行业已较为普遍,但大型化需浮运的沉箱施工有其特点。从港珠澳大桥沉管预制厂大型化沉箱模板的设计和施工入手,对特别需要注意的方面进行探讨,得到一些有益的经验。

  16. The reflection of regular and irregular waves by a partially perforated caisson breakwater on a step bed

    Institute of Scientific and Technical Information of China (English)

    LIU Yong; LI Yucheng; TENG Bin; XIA Zhisheng

    2009-01-01

    This study examines the reflection of regular and irregular waves from a partially perforated caisson breakwater located on a step bed. The step bed is treated as an idealized rubble mound foundation. Based on the linear potential theory, an analytical solution is developed to calculate the reflection coefficient of the structure subjected to regular waves. The matched eigenfunction expansion method is used for the solution. The regular wave method is also extended to irregular waves using a linear transfer function. The calculated results obtained for limiting cases are exactly the same as corresponding results given by the previous researchers. The present predictions also agree well with experimental data in the published literatures. Numerical experiments are conducted to examine the variations of the reflection coefficient versus its main effect factors, and some interesting results are presented.

  17. 武汉鹦鹉洲长江大桥北锚碇新型沉井基础设计%Design of New Type Caisson Foundation for North Anchorage of Yingwuzhou Changjiang River Bridge in Wuhan

    Institute of Scientific and Technical Information of China (English)

    李明华; 杨灿文

    2011-01-01

    The main bridge of Yingwuzhou Changjiang River Bridge in Wuhan is a three-tower and four-span suspension bridge. After comparison of different design proposals, it was determined that a new type caisson structure of circular cross section and with multiple round wells would be used for the north anchorage foundation of the bridge. In the big size well in the center of the caisson, the crisscross diaphragm was set and along the periphery within the caisson, a number of small size wells were uniformly set. The caisson is 43 m high and has totally 8 lifts, of which the first lift is a steel shell concrete caisson and the rest parts of the caisson from the second to the eighth lifts are all of reinforced concrete caissons. In the construction of the caisson, the caisson was sunk down by no dewatering and the air curtain was provided in the caisson wall to reduce sinking difficulty and construction risk. The software FLAC3D was used to conduct numerical simulation and analysis of the construction process of the sinking and to evaluate the construction safety, the environmental effect caused by the construction and the deformation of the foundation to be applied with load after the bridge was put into operation. The results of the a-nalysis show that in the process of sinking the caisson in lifts, the caisson structure and ground deformation can meet the relevant requirements in the codes and the adverse influence of the construction on the ambient buildings and the river dyke can be effectively avoided.%武汉鹦鹉洲长江大桥主桥为三塔四跨悬索桥.该桥北锚碇基础经多方案比选采用多圆孔环形截面新型沉井结构.沉井中间大圆孔内设置十字形隔墙,圆环内沿圆周均布有小直径井孔.沉井总高43 m,共分8节,第1节为钢壳混凝土沉井,第2~8节均为钢筋混凝土沉井.北锚碇施工中采用不排水下沉、井壁增加空气幕等措施减小施工难度及风险.采用软件FLAC3D对沉井施工过程进

  18. Protection for work in the pressure tank of the pile G2; Protection des travaux dans le caisson de la pile G2

    Energy Technology Data Exchange (ETDEWEB)

    Chassany, J.Ph.; Rodier, J. [Commissariat a l' Energie Atomique, Service de Protection contre les Radiations, Marcoule (France). Centre d' Etudes Nucleaires

    1961-07-01

    While the pile was shut down after a three-month run at full power, the secondary circuit was cleaned and some alterations were carried out. The pile contained 100 tons of uranium, half of which made up the periphery and was irradiated uranium. The possibility of carrying on work inside the pressure tank was not considered at the time of construction. Because of the heat and the irradiation it was only possible to remain in the pressure tank for a limited period of time, and several operators received doses of the order of 1.5 rem. Cotton clothing gave satisfactory protection against contamination and was more comfortable than the vinyl equipment. The work lasted for 17 days and involved 881 incursions into the pressure tank. (author) [French] Un nettoyage et des modifications ont ete realises dans le circuit secondaire pendant l'arret de la pile apres un fonctionnement de trois mois a pleine puissance. La pile contenait 100 tonnes d'uranium dont la moitie, composant la peripherie, etait de l'uranium irradie. La possibilite d'entreprendre un travail a l'interieur du caisson n'avait pas ete envisage lors de la construction. Le temps de sejour dans le caisson etait a la fois limite par l'irradiation et la chaleur, plusieurs operateurs, ont integre une dose de l'ordre de 1,5 rem. Les vetements de coton ont apporte une protection contre la contamination satisfaisante et un confort relatif par rapport aux equipements de vinyle. L'intervention a dure 17 jours, a comporte 881 entrees dans le caisson. (auteur)

  19. Experimental Research for Denitrification by Caisson Filler Enhanced MBR Process%沉箱填料强化MBR工艺脱氮的试验研究

    Institute of Scientific and Technical Information of China (English)

    李旭宁; 裴廷权; 刘欢; 赵振业; 梅立永; 张锐

    2012-01-01

    [目的]研究沉箱填料强化MBR工艺对有机物和氮的去除效果.[方法]通过向MBR反应池投加沉箱填料处理生活污水,研究沉箱填料强化MBR工艺对有机物和氮的去除效果.[结果]未加填料和已投填料的出水COD均值分别为26.8、24.7 mg/L,投加填料比未加填料的脱氮效果要好,对NH3-N去除率均值分别为98.44%、96.37%;对TN去除率均值分别24.03%、16.43%.出水COD和NH3-N浓度低于《城镇污水处理厂污染物排放标准》(GB18918-2002)一级A标准.出水TN主要以NO3-N形式存在(98.06%),NH3-N和NO2-(-0N所占的比例很小,只占整个TN的1.22%和0.72%.对反硝化脱氮研究的进一步建议:①沉箱填料与反应池体积比重增至4%~5%;②更换单个体积较小,内部纤维量较多的填料;③适量减少曝气量,使MBR反应池内的DO减少到1.5 ~3.0 mg/L.[结论]该研究为今后的工程实践提供了理论依据.%[ Objective ] The research aimed to study removal effects of the organic matter and N by caisson filler enhanced MBR process. [ Method ] By adding caisson filler to reaction pool of the MBR to treat domestic sewage, removal effects of the organic matter and N by caisson filler enhanced MBR process were studied. [Result] COD means in effluent were respectively 26. 8 and 24.7 mg/L by without adding filler and with adding filler. Average removal rates of the NH3-N were 98.44% and 96. 37% , while average removal rates of the TN were 24.03% and 16.43% , respectively. COD and NH3-N concentrations in effluent were lower than the first A grade criteria of Discharge Standard of the Pollutant for Municipal Wastewater Treatment Plant (GB18918-2002). NO3--N was main form of the TN in effluent and occupied 98. 06% , while NH3 -N and NO2- -N only accounted for 1. 22% and 0. 72% . Further suggestion for denitrification study was as below. Firstly, the proportion of caisson filler on volume of the reaction cell should be increased to 4% -5

  20. Floating Resistance Analysis for No .28 Pier Steel Caisson of Hutong Changjiang River Bridge%沪通长江大桥28号墩钢沉井浮运阻力分析

    Institute of Scientific and Technical Information of China (English)

    陈涛

    2015-01-01

    The main navigational channel bridge of Hutong Changjiang River Bridge is a steel truss girder cable‐stayed bridge with span arrangement of (142+462+1 092+462+142) m .The foundations of the pylon piers adopt caisson foundations ,among w hich the top plan dimension of steel caisson of pier No .28 is 86 .9 m by 58 .7 m ,and 44 m high .The steel caisson for the pier No .28 was fabricated in a dock and then transported to the bridge site by floating ,with a total floating weight of up to 14 500 t .To rationally allocate the floating tugboats and assure smooth floating ,the theoretical method ,numerical simulation method and physical model testing method were used to calculate the floating resistance of the steel caissons .Based on the comparative analy‐sis ,by modifying the head and end shapes of the boats ,the results gained by using the method presented in the Guidelines for Towage At Sea is approximate to those gained respectively by nu‐merical simulation and physical model testing ,w hich is proved applicable to the floating resistance calculation for the steel caisson of pier No .28 .It is proposed by calculation that the steel caissons have a draft of 8 m ,when the wind speed is at Grade 6 ,and the tugboat′s speed through water is 2 . 5 m/s ,the total resistance for a steel caisson is 2 167 kN under the condition of longitudinal to‐wing .The arrangement of the tugboats adopts the“7+1”mode ,namely one used as a backup tug‐boat ,the efficient output towing force is 3 060 kN ,and the maximum resistance of the towing is 2 326 .74 kN ,satisfying the floating requirements of the steel caisson .%沪通长江大桥主航道桥为(142+462+1092+462+142) m钢桁梁斜拉桥,桥塔墩基础采用沉井基础,其中28号墩钢沉井顶平面尺寸为86.9 m ×58.7 m ,高44 m。28号墩钢沉井在船坞内制造完后整体浮运至桥址处,浮运总重达14500 t。为合理地配置浮运拖轮,确保浮运顺利,采用理论方

  1. Control Technique for Accurate Landing of Caisson of Pier No.3 of Tongling Changjiang River Bridge on Hefei-Fuzhou Railway onto Riverbed%合福铁路铜陵长江大桥3号墩沉井精确着床控制技术

    Institute of Scientific and Technical Information of China (English)

    覃勇刚; 涂满明; 王东辉

    2013-01-01

    The main bridge of Tongling Changjiang River Bridge on Hefei-Fuzhou Railway is a steel truss girder cable-stayed bridge with three cable planes and with a main span 630 m. The Pier No. 3 of the north pylon of the bridge is supported on the foundation of round-ended caisson that was constructed by the scheme of "two-time positioning and quick landing of the caisson onto the riverbed by water pumping". To make sure that the caisson could be accurately landed onto the riverbed, the spatial model for the caisson and its tie anchor rope system was set up by the finite element software MIDAS 2006, the process of the landing of the caisson was simulated, the changing laws of the caisson offsetting and anchor rope forces in the process of the landing were analyzed and it was determined that the distance between the bottom of the caisson and the riverbed should be kept 2 m at the time the caisson was being positioned. To minimize the influences of the scouring, soil non-uniformity of the riverbed, waves and vortex vibration on the accurate landing of the caisson onto the riverbed, the measures of pumping water into the caisson for quick landing of the caisson, rectifying the offsetting of the caisson by winching the anchors, increasing the numbers and rigidity of the side anchors of the caisson and increasing the mass and damping of the caisson itself were respectively taken.%合福铁路铜陵长江大桥主桥为主跨630 m的三索面钢桁梁斜拉桥,其北桥塔3号墩采用圆端形沉井基础,沉井着床采用“二次定位、注水快速着床”的方案.为使沉井精确着床,采用MIDAS 2006有限元软件建立沉井和拉缆系统空间模型,模拟沉井着床过程,分析沉井着床过程中的偏移及拉缆索力变化规律,确定定位时沉井底与河床的距离为2 m.为减小冲刷、河床平面土质分布不均、波浪和涡激振动等对沉井精确着床的影响,分别采取了注水快速着床、绞锚纠偏回位、增加沉井边

  2. 水平荷载作用下裙式吸力基础承载性能研究%Bearing capacity of skirted suction caisson in sand under horizontal monotonic/cyclic loading

    Institute of Scientific and Technical Information of China (English)

    李大勇; 曹立雪; 高盟; 刘炜炜

    2013-01-01

    Traditional suction caisson is an upside down bucket-shaped structure, which is widely used as an alternative to support offshore platforms and mooring floating structures. It currently acts extensively as the foundation of offshore wind turbines. Its lateral bearing capacity plays an important role in the design. To increase the lateral bearing capacity, a new type of suction caisson, the skirted suction caisson, is presented. The skirted suction caisson in sand is investigated in comparison with the traditional suction caisson by u-sing the finite element method under the monotonic and cyclic loading. The corresponding load-deformation curves are obtained. The results show that the horizontal bearing capacity is significantly enhanced to resist the static and cyclic loads due to the additional structure of the skirt.%传统吸力基础是一个单桶结构,被广泛作为海洋平台、漂浮结构的基础,近年来也被推广到海上风电塔架.作为风电塔架基础,要充分提高其水平承载能力.为此,提出一种改进的基础形式一裙式吸力基础.采用Z_SOIL有限元软件,针对砂土地基,从水平单调加载和循环加载两个方面,对传统单桶吸力基础和裙式吸力基础进行了承载性能对比研究,得到了相应的荷载-位移曲线.研究结果表明,裙式吸力基础由于设置了“裙”结构,显著提高了其抵抗水平静载和循环水平动力荷载的能力,并能有效控制基础的水平位移,是值得推广应用的一种新型海洋工程基础形式.

  3. Scheme of Pressure Boost and Floating Aid for Steel Open Caisson of Main Ship Channel Bridge of Hutong Changjiang River Bridge%沪通长江大桥主航道桥钢沉井增压助浮方案

    Institute of Scientific and Technical Information of China (English)

    余允锋; 邱琼海; 王立忠

    2015-01-01

    The main ship channel bridge of the Hutong Changjiang River Bridge is a double-py-lon continuous steel truss girder cable-stayed bridge with span arrangement (140+462+1 092+462+140) m .T he foundations for the main piers of the bridge are all the open caissons ,of w hich the plan dimensions of the caisson top of the main pier No .29 are 86 .9 m × 58 .7 m and in the plan of the caisson ,24 well holes are arranged .The total height of the caisson of the pier is 115 m and the lower part of the caisson is the steel caisson that is 56 m in height .In the state of free floating , the draught of the steel caisson is 12 .5 m ,the caisson can not be floated out of the shipyard be-cause of the deep draught and has the risk of grounding in the floating .To reduce the draught of the caisson and to keep the pressure in the air cabins of the caisson stable ,the scheme of pressure boost and floating aid for the caisson was proposed ,that was ,12 well holes in the caisson were symmetrically closed to make the well holes the sealed cabins .Meanwhile ,the active pressure boost system was arranged and the air was injected into the cabins from the tops of the closing cov-er plates of the well holes .The pressure boost system was composed of the air compressor ,main air pipes ,branch air pipes ,extension air pipes ,air pressure meters ,check valves ,stop valves and liquid level sensors .By the measures of injecting the air for pressure boost and releasing the air for pressure reduction ,the air pressure in each cabin was controlled .With the scheme of the pressure boost and floating aid ,the steel open caisson of the pier was finally floated out from the shipyard to the pier site only in 3 h and the effect of the scheme implementation was sound .%沪通长江大桥主航道桥为(140+462+1 092+462+140 ) m双塔连续钢桁梁斜拉桥 ,该桥主墩均采用沉井基础 ,其中 ,29号主墩沉井顶平面尺寸为86 .9 m × 58 .7 m ,平面布置24个井孔 ,高115m,下部钢沉井高56

  4. 砂土中吸力式沉箱基础的最大承载力计算方法%Calculation method for maximum bearing capacity of suction caisson foundation in sand

    Institute of Scientific and Technical Information of China (English)

    黎冰; 高玉峰; 沙成明; 童小东

    2012-01-01

    To accurately determine the maximum pull-out loading capacity of suction caisson foundation in sand, the limit equilibrium method is applied. Based on the mechanical characteristics of suction caisson foundation with horizontal translation, a method for three-dimensional limit equilibrium analysis of maximum pull-out loading capacity of suction caisson foundation in sand is proposed. In the proposed method, the development process of earth pressure and shear resistance with displacement, and the characteristics of different earth pressure and side shear resistance over the caisson cross-section are considered. The earth pressure acting on the caisson is assumed to obey the Winkler model and is not in excess of the limiting earth pressure. The shear resistance between caisson and soil is assumed to be linearly proportional to the relative displacement between them before reaching its ultimate value. Fifteen model tests of suction caisson foundation under horizontal loading in sand are conducted to investigate its pull-out behaviors, and the load-displacement curves are obtained. The calculation results by the proposed method agree well with the experimental results, indicating that the proposed method is accurate and effective. Key w%为了准确确定砂土中吸力式沉箱基础的最大承载力,应用极限平衡法对其进行分析.基于吸力式沉箱基础平动时的受力特点,充分考虑土压力和摩擦力的发挥过程以及沉箱横截面上各点土压力大小的不同,提出了一种计算砂土中吸力式沉箱基础最大承载力的三维极限平衡方法.方法中假定沉箱侧壁土压力满足Winkler模型,但其值不超过水平极限土压力值;假定沉箱侧壁与地基土之间的摩擦力在达到最大值之前与两者之间的相对位移成线性正比关系.开展了15组水平荷载作用下吸力式沉箱基础的模型试验,得到了吸力式沉箱基础的荷载-位移曲线.利用所提方法得到的计

  5. 锚碇沉箱基础与升浆基床摩擦性能研究%Research on friction property between anchorage caisson foundation and grouting bed

    Institute of Scientific and Technical Information of China (English)

    耿铁锁; 陈亮; 张哲

    2015-01-01

    According to the first domestic offshore suspension bridge using caisson foundation,the friction property between prepacked aggregate riprap grouting bed and concrete under water,the friction coefficients between gravel bed and concrete structure are mainly studied.Firstly,the friction coefficients between gravel bed and concrete structure are obtained by laboratory and field experiments,and then,the friction property between prepacked aggregate riprap grouting bed and concrete structure under water is acquired by the numerical analysis method.The experimental results show that the friction coefficients between the common gravel bed and the concrete caisson are in the range of 0.5-0.6,which meets the corresponding code,and the friction coefficient between the prepacked aggregate riprap grouting bed and the concrete caisson is within 0.7-0.8,or even 0.9 considering the film cohesive force of concrete.%针对国内首个采用沉箱基础的海上悬索桥,主要对水下预填骨料抛石升浆基床与混凝土之间的摩擦性能,以及碎石基床与混凝土结构的摩擦因数展开研究.首先通过室内和现场实验得到碎石基床与混凝土结构的摩擦因数,在此基础上采用数值分析方法得到水下预填骨料抛石升浆基床与混凝土结构之间的摩擦性能.结果表明,普通碎石基床与混凝土沉箱之间的摩擦因数在设计规范规定的0.5~0.6内,而预填骨料抛石升浆基床与混凝土沉箱之间的摩擦因数为0.7~0.8,如考虑混凝土之间的黏结力膜作用,摩擦因数可达0.9.

  6. 沉井预封底水力冲洗下沉工艺在砂质地层中的应用%Application of bottom sealing of caisson hydraulic flushing sinking process in sandy stratum

    Institute of Scientific and Technical Information of China (English)

    安治国

    2013-01-01

    The main geology around Shanghai branch gas pipeline (area of Jiangsu,Zhejiang,Shanghai) of the east segment of the Second West-to-East Gas Pipeline Project,is sandy soil,with high moisture content of soil and underground water level.In order to solve the problems like water and sand gushing,long bottom sealing cycle and so on,in light of the current construction way of pipe-jacking tunnels and caisson at Yongli River,prefabed bottom sealing is adopted.Combined with engineering cases,the paper presents the control points such as geological prospecting,process design,equipment selection,deviation-rectifying of sink,risk prediction,preventive measures and so on.The successful application of bottom sealing of caisson hydraulic flushing sinking process shortens the construction period about 39 %,saves about 37.28 % of construction costs,reduces the disturbance to the formation outside the caisson,ensures the safety of structures around the environment,lowers the difficulty in coordinating public relations.%西气东输二线东段上海支干线途经区域(苏浙沪地区)地质主要为砂质地层,土壤含水率及地下水位较高,为解决顶管隧道沉井涌水涌砂、封底周期长等难题,针对永利河顶管隧道沉井施工现状,采用沉井预封底水力冲洗下沉工艺进行施工.结合工程实例,阐述了地质勘查、工艺制定、设备选择、沉井纠偏、风险预测及防范措施等控制要点.沉井预封底水力冲洗下沉工艺在该工程中的成功应用,有效缩短施工周期约39%,降低施工成本约37.28%,减少了对井外地层的扰动,保证了周围建(构)筑物的安全,降低了公共关系协调难度.

  7. Radio-activity measurements inside the pressure-vessel of the reactor G 3 after 4 years operation; Mesure de radioactivite a l'interieur du caisson de la pile G. 3 apres 4 ans de fonctionnement

    Energy Technology Data Exchange (ETDEWEB)

    Chassany, J.Ph.; Guillermin, P.; Delmar, J. [Commissariat a l' Energie Atomique, Centre de Production de Plutonium, Marcoule (France). Centre d' Etudes Nucleaires

    1965-07-01

    At the end of the piping coming into the vessel, the dose rate reached 75 mR/hr and 100 mR/hr near the deflector. On the other side of this deflector it was still 100 mR/hr and then increased rapidly to over 1 R/hr at 1 metre distance from the starting-up chambers. On the sides, the flux tended to decrease (80 mR/hr) and was 2 R/hr at a height of 3 metres. This dose rate could certainly have been decreased by discharging the peripheral zone of the reactor. Consequently it should be possible to intervene if necessary, on condition that great care is taken to avoid contamination and that the total dose is followed as precisely as possible during the operations. (authors) [French] A la sortie de la tuyauterie debouchant dans le caisson, le debit de dose atteignait 75 mR/h et 100 mR/h pres du deflecteur. Au-dela de ce deflecteur il etait encore de 100 mR/h puis augmentait rapidement depassant 1 R/h a 1 m des chambres de demarrage. Sur les cotes, le flux tendait a diminuer (80 mR/h) pour atteindre 2 R/h a 3 m de hauteur. Ce debit de dose aurait certainement pu etre diminue en dechargeant la zone peripherique de la pile. Par consequent une intervention dans le caisson serait realisable moyennant des precautions severes contre la contamination et une surveillance stricte des doses integrees. (auteurs)

  8. Dynamic Behaviour of Suction Caissons

    DEFF Research Database (Denmark)

    Liingaard, Morten

    to account for the possibilities of dynamic effects of the soil-structure interaction. The aim of this thesis is to evaluate the dynamic soil-structure interaction of foundations for offshore wind turbines, with the intention that the dynamic properties of the foundation can be properly included...... and dynamic behaviour of the foundation are predicted accurately with the applied model. The analysis has been carried out for different combinations of the skirt length, soil stiffness and the Poisson's ratio of the subsoil. Subsequently, the high-frequency impedance has been determined for the use in lumped...... the last 25 years. In order to reduce the costs, the overall weight of the wind turbine components is minimized, which means that the wind turbine structures become more flexible and thus more sensitive to dynamic excitation. Since the first resonance frequency of the modern offshore wind turbines is close...

  9. Foundation Design of Caisson Breakwaters

    DEFF Research Database (Denmark)

    Groot, M.B. De; Andersen, K.H.; Burcharth, H. F.;

    1996-01-01

    This document has been prepared as a part of the dissemination of results of the MCS-Project (Contract No. MAS2-CT92-0047) which was led by the University of Hannover (Coordinator: H. Oumeraci) within the 2nd Research Programme of the European Union (EU) on Marine and Science Technology. The supp...

  10. Dynamic stiffness of horizontally vibrating suction caissons

    DEFF Research Database (Denmark)

    Latini, Chiara; Zania, Varvara; Cisternino, Michele

    2016-01-01

    to existing analytical solutions suggested for piles. Relatively good agreement has been achieved comparing the numerical results with the analytical solutions. Then, the effect of the soil layer shear wave velocity on the dynamic stiffness coefficients is analysed. The results have indicated that increasing...

  11. Experimental Investigation on Caisson Breakwater Sliding

    DEFF Research Database (Denmark)

    Ruol, Piero; Martin, Paolo; Andersen, Thomas Lykke;

    2014-01-01

    weight and same geometries are tested under regular and irregular waves. It is found that, under breaking conditions, the expected inaccuracy of the prediction of the force, inherent on the variability of the breaking process, induce unacceptable errors in the prediction of the sliding. This observation...... endorses other previous experimental results. Conversely, when the actual measured input force is used as input, the analytical Shimosako formula fit quite well the experimental sliding distance....

  12. Monitoring the performance of an alternative cover using caisson lysimeters

    Energy Technology Data Exchange (ETDEWEB)

    Waugh, W.J.; Smith, G.M.; Mushovic, P.S.

    2004-02-29

    The U.S. Department of Energy (DOE) office in Grand Junction, Colorado, and the U.S. Environmental Protection Agency (EPA), Region 8, collaborated on a series of field lysimeter studies to design and monitor the performance of an alternative cover for a uranium mill tailings disposal cell at the Monticello, Utah, Superfund Site. Because groundwater recharge is naturally limited at Monticello in areas with thick loess soils, DOE and EPA chose to design a cover for Monticello using local soils and a native plant community to mimic this natural soilwater balance. Two large drainage lysimeters fabricated of corrugated steel culvert lined with high-density polyethylene were installed to evaluate the hydrological and ecological performance of an alternative cover design constructed in 2000 on the disposal cell. Unlike conventional, lowpermeability designs, this cover relies on (1) the water storage capacity of a 163-cm soil “sponge” layer overlying a sand-and-gravel capillary barrier to retain precipitation while plants are dormant and (2) native vegetation to remove precipitation during the growing season. The sponge layer consists of a clay loam subsoil compacted to 1.65 g/cm2 in one lysimeter and a loam topsoil compacted to 1.45 g/cm2 in the other lysimeter, representing the range of as-built conditions constructed in the nearby disposal cell cover. About 0.1 mm of drainage occurred in both lysimeters during an average precipitation year and before they were planted, an amount well below the EPA target of <3.0 mm/yr. However, the cover with less compacted loam topsoil sponge had a 40% greater water storage capacity than the cover with overly compacted clay loam subsoil sponge. The difference is attributable in part to higher green leaf area and water extraction by plants in the loam topsoil. The lesson learned is that seemingly subtle differences in soil types, sources, and compaction can result in salient differences in performance. Diverse, seeded communities of predominantly native perennial species were established on both lysimeters during an extended 3-yr drought, highlighting the importance of a sound understanding of the local ecology and of implementing the science and methods of disturbed-land revegetation.

  13. Decompression syndrome (Caisson disease in an Indian diver

    Directory of Open Access Journals (Sweden)

    Phatak Uday

    2010-01-01

    Full Text Available Acute decompression syndrome (Caisson′s disease is an acute neurological emergency in divers. It is caused due to release of nitrogen gas bubbles that impinge the blood vessels of the spinal cord and brain and result in severe neurodeficit. There are very few case reports in Indian literature. There are multiple factors in the pathogenesis of Acute decompression syndrome (Caisson′s disease such as health problems in divers (respiratory problems or congenital heart diseases like atrial septal defect, patent ductus arteriosus etc, speed of ascent from the depth and habits like smoking that render divers susceptible for such neurological emergency. Usually, immediate diagnosis of such a condition with MRI is not possible in hospitals in the Coastal border. Even though, MRI is performed, it has very low specificity and sensitivity. Facilities like hyperbaric oxygen treatment are virtually non-existent in these hospitals. Therefore, proper education of the divers and appropriate preventive measures in professional or recreational divers is recommended.

  14. Laboratory Setup for Vertically Loaded Suction Caisson Foundation in Sand and Validation of Responses

    OpenAIRE

    Manzotti, E.; Vaitkunaite, Evelina; Ibsen, Lars Bo

    2014-01-01

    Wind energy obtained by means of wind turbine has been proved to be a concrete resource of green energy. Development of such structures requires research on offshore construction, since this is the direction for future improvement on this field. Wind turbines are relatively light and slender devices usually installed in farms, therefore many inexpensive foundations are needed. Suction Bucket foundations are a suitable option for this purpose, but for large scale utilization more research is r...

  15. Two-Dimensional Model Test Study of the New Caisson Breakwater at Playa Blanca, Lanzarote

    DEFF Research Database (Denmark)

    Andersen, Thomas Lykke; Garborg, Karsten; Stagsted, Esben Rubech

    This report present the results of 2-D physical model tests (length scale 1:42.5) carried out in a wave flume at Department of Civil Engineering, Aalborg University (AAU) on behalf of SENER Ingenera y Sistemas S.A. Associate Prof. Thomas Lykke Andersen was in charge of the model tests, assisted...

  16. Three-Dimensional Model Test Study on the Existing Caisson Breakwater at Port of Castellon, Spain

    DEFF Research Database (Denmark)

    Nørgaard, Jørgen Harck; Andersen, Thomas Lykke

    This report present the results of 3-D physical model tests (length scale 1:60) carried out in a wave basin at Department of Civil Engineering, Aalborg University (AAU) on behalf of the client; BP OIL ESPAÑA. Associate Prof. Thomas Lykke Andersen and M.Sc. Jørgen Quvang Harck Nørgaard were in cha...

  17. Laboratory Setup for Vertically Loaded Suction Caisson Foundation in Sand and Validation of Responses

    DEFF Research Database (Denmark)

    Manzotti, E.; Vaitkunaite, Evelina; Ibsen, Lars Bo

    Wind energy obtained by means of wind turbine has been proved to be a concrete resource of green energy. Development of such structures requires research on offshore construction, since this is the direction for future improvement on this field. Wind turbines are relatively light and slender...... devices usually installed in farms, therefore many inexpensive foundations are needed. Suction Bucket foundations are a suitable option for this purpose, but for large scale utilization more research is required, especially for in-service performance. Size of offshore wind turbine has been increasing...... during the last years and, following this trend, design choice will turn into foundation composed of three or four suction bucket foundations, called respectively tripod and tetrapod. Overturning moment in tripod and tetrapod is carried by vertical loading; therefore vertical pull-out capacity is tested...

  18. Finite element simulation of KICT open caisson - soil - piles%KICT沉井-土-桩有限元模拟

    Institute of Scientific and Technical Information of China (English)

    丁建军; 王婷婷

    2010-01-01

    该文采用有限元软件Abaqus V6.5 standard平台,建立有限元模型,模拟KICT新码头沉井-土-桩之间的相互作用,分析各个阶段的位移场和应力场,以及主要构件的受力情况,为改造后的结构安全评估提供参考.

  19. Small Concrete Caisson Applied to Underwater Pipeline Construction%小型混凝土沉箱在水下管道施工中的应用

    Institute of Scientific and Technical Information of China (English)

    李伟民

    2012-01-01

    以上海外高桥油脂加工区泵房取水口管道工程为例,介绍了施工中遇到的降水和选择何种方案的难题。由此,通过各方分析和论证,采用了小型预制钢筋混凝土沉箱整体沉放的方法,顺利地解决了难题。经施工应用表明,该方法质量可靠、施工简便、造价低、工期短,取得了较好的效益。

  20. Characterization of materials for a reactive transport model validation experiment: Interim report on the caisson experiment. Yucca Mountain Site Characterization Project

    Energy Technology Data Exchange (ETDEWEB)

    Siegel, M.D.; Cheng, W.C. [Sandia National Labs., Albuquerque, NM (United States); Ward, D.B.; Bryan, C.R. [Univ. of New Mexico, Albuquerque, NM (United States). Dept. of Earth and Planetary Sciences

    1995-08-01

    Models used in performance assessment and site characterization activities related to nuclear waste disposal rely on simplified representations of solute/rock interactions, hydrologic flow field and the material properties of the rock layers surrounding the repository. A crucial element in the design of these models is the validity of these simplifying assumptions. An intermediate-scale experiment is being carried out at the Experimental Engineered Test Facility at Los Alamos Laboratory by the Los Alamos and Sandia National Laboratories to develop a strategy to validate key geochemical and hydrological assumptions in performance assessment models used by the Yucca Mountain Site Characterization Project.

  1. 数字化近景摄影及在大型沉井工程中的应用%DIGITAL CLOSE-RANGE PHOTOGRAMMETRY AND ITS APPLICATION TO LARGE-SCALE CAISSON PROJECT

    Institute of Scientific and Technical Information of China (English)

    寇新建; 黄醒春

    2000-01-01

    该文介绍了数码手像机进行工程监测的优点及所需的软件环境.在工程摄影中采用数码像机不仅可以消除像片变形误差、准确提供像机的内方位元素,而且无需冲洗、复制像片,有利于提高效率和像片处理计算机化.这对采用摄影测量进行工程监控提供了有效途径.作者对数码手像机进行大型沉井观测的实例作了简要介绍.

  2. The Importance of Pressure Sampling Frequency in Models for Determination of Critical Wave Loadings on Monolithic Structures

    DEFF Research Database (Denmark)

    Burcharth, Hans F.; Andersen, Thomas Lykke; Meinert, Palle

    2008-01-01

    Wave induced pressures on model scale monolithic structures like caissons and concrete superstructures on rubble mound breakwaters show very peaky variations, even in cases without impacts from slamming waves.......Wave induced pressures on model scale monolithic structures like caissons and concrete superstructures on rubble mound breakwaters show very peaky variations, even in cases without impacts from slamming waves....

  3. The Importance of Pressure Sampling Frequency in Models for Determination of Critical Wave Loadingson Monolithic Structures

    DEFF Research Database (Denmark)

    Burcharth, Hans F.; Andersen, Thomas Lykke; Meinert, Palle

    2008-01-01

    This paper discusses the influence of wave load sampling frequency on calculated sliding distance in an overall stability analysis of a monolithic caisson. It is demonstrated by a specific example of caisson design that for this kind of analyses the sampling frequency in a small scale model could...... be as low as 100 Hz in model scale. However, for design of structure elements like the wave wall on the top of a caisson the wave load sampling frequency must be much higher, in the order of 1000 Hz in the model. Elastic-plastic deformations of foundation and structure were not included in the analysis....

  4. Helix Project Testbed - Towards the Self-Regenerative Incorruptible Enterprise

    Science.gov (United States)

    2011-09-14

    target audience of the language, hardware architects. We have implemented a compiler for Caisson that translates designs into Verilog and then...tag for each bit in the memory and cache. We implemented the Base processor (from the Nios design) in Verilog with no additional security features...important test for the usability of a language. We find anecdotally that Caisson is easily usable by a programmer trained in Verilog . The original Base

  5. On Optimum Safety Levels of Breakwaters

    DEFF Research Database (Denmark)

    Burcharth, Hans F.; Sørensen, John Dalsgaard

    2006-01-01

    to resist geotechnical slip failures. Optimum safety levels formulated for use both in deterministic and probabilistic design procedures are given. Results obtained so far indicate that the optimum safety levels for caisson breakwaters are much higher than for rubble mound breakwaters.......The paper presents results from numerical simulations performed with the objective of identifying optimum design safety levels of conventional rubble mound and caisson breakwaters, corresponding to the lowest costs over the service life of the structures. The work is related to the PIANC Working...... Group 47 on "Selection of type of breakwater structures". The paper summaries results given in Burcharth and Sorensen (2005) related to outer rubble mound breakwaters but focus on optimum safety levels for outer caisson breakwaters on low and high rubble foundations placed on sea beds strong enough...

  6. Embedment Effects on the Vertical Bearing Capacity of Offshore Bucket Foundations on Cohesionless Soil

    DEFF Research Database (Denmark)

    Barari, Amin; Ibsen, Lars Bo; Ghalesari, Abbasali Taghavi;

    2017-01-01

    This paper presents the results from a series of physical modeling and three-dimensional finite 9 element (FE) analyses, which examined the uniaxial vertical capacity of suction caissons for 10 offshore wind turbines. The experiments were carried out in quartz sand and involved monotonic 11...... application of vertical load. It was found that the drained capacity of suction caissons is 12 dependent on embedment ratio. On the other hand, predictions from conventional semi-empirical 13 depth factors were found to somewhat underestimate when applied to rough foundations. On the 14 basis of the tests...

  7. Suez Canal Clearance Operation, Task Force 65

    Science.gov (United States)

    1975-05-01

    and remove the four wrecks from the central region of the canal; DREDGE 23, Tug MONGUED, Dredge KASSER and a Concrete Caisson. All salvage operations...feet BUCKET DREDGE NO. 23 72.00 1600 tons 191 feet TUG MONGUED 81.50 1200 tons 165 feet DIPPER DREDGE KASSER 81.50 1200 tons 125 feet CONCRETE CAISSON...MONGUED, DREDGE KASSER , and DREDGE 23 to wet dump in the Great Bitter Lake. Heavy crane THOR arrived in Port Said after transit from Hamburg, Germany

  8. Validity of simplified Analysis of Stability of Caison Breakwaters on Rubble Foundation Exposed to Impulsive Loads

    DEFF Research Database (Denmark)

    Andersen, Lars; Burcharth, Hans F.; Andersen, Thomas Lykke

    2011-01-01

    Wave slamming on vertical breakwaters cause a sudden, impulsive load that may cause a caisson to slide on its foundation. Alternatively, geotechnical failure may occur in the subsoil. This paper investigates whether simple analytical solutions, accounting only for the sliding along the caisson–fo......, a fully coupled dynamic pore-water-flow model is introduced. The computational examples clearly demonstrate that the deformations of the soil as well as the pore pressures must be accounted for in order to get a reliable prediction of caisson deformations during wave impact....

  9. Techniques for Diving Deeper Than 1,500 Feet,

    Science.gov (United States)

    1980-03-01

    en caisson. A suppaser que le facteur limitant respiratoire n’interviemne pas trop a ces profondeurs. 29. 0. 0 t4 CP o I Co, 0 °. 0 E0 0 0 -.Ŕ o Ll...decompressions rapides: Influence de l’azote dans le melange respiratoire . Med. Subaq. et Hyperbare 15:267-270. 23. Rostain, J.C., Dumas, J.C., Gardette, B...Simulated caisson disease of bone. In: Hesser, D.M. and D. Linnarsson, eds. Proceedings of the first annual scientific meeting of the European Undersea

  10. Validity of Simplified Analysis of Stability of Caison Breakwaters on Rubble Foundation Exposed to Impulsive Loads

    DEFF Research Database (Denmark)

    Andersen, Lars; Burcharth, Hans F.; Andersen, Thomas Lykke

    Excessive sliding and foundation failures are common failure modes for caisson breakwaters on rubble foundations. An accurate evaluation of these failure modes demands a dynamic analysis in the time domain, and due to the complexity of the material response, numerical solution methods must be app...

  11. Wave Pressures on Seawave Slot-Cone Generator

    DEFF Research Database (Denmark)

    Vicinanza, Diego; Kofoed, Jens Peter; Frigaard, Peter

    2006-01-01

    This paper presents results on loading action on an innovative caisson breakwater for electricity production. The work reported here contributes to the European Union Sixth Framework programme priority 6.1 (Sustainable Energy System), contract 019831, titled "Full- scale demonstration of robust a...

  12. Interaction Between Waves and A Comb-Type Breakwater

    Institute of Scientific and Technical Information of China (English)

    董国海; 李玉成; 孙昭晨; 孙洋; 牛恩宗; 毛铠

    2003-01-01

    The characteristics of wave transmission, reflection and energy dissipation of comb-type caisson breakwaters are studied through laboratory physical model tests. Regular and irregular waves, with a wide range of wave heights and periods and a constant water depth, are considered. Different dimensions of each portion of the comb-type caisson breakwater are tested. Empirical formulae for calculating the reduction coefficient k, which is the ratio of horizontal wave force on unit length of the comb-type breakwater to that on unit length of the vertical wall breakwater, and for calculating the reflection coefficient of waves kr are obtained from the measurements. The comb-type caisson breakwater has been found to be very efficient in dissipating incident wave energy and in reducing wave reflection, and has already been used for the construction of an island breakwater in the Dayao Bay of Dalian Port, Liaoning Province, China. Compared with the cost of a common caisson breakwater, about 24.5% of the investment has been saved owing to the use of this comb-type breakwater.

  13. Wave Motion Compensation Scheme and Its Model Tests for the Salvage of An Ancient Sunken Boat

    Institute of Scientific and Technical Information of China (English)

    YE Jia-wei; CHEN Yuan-ming; WANG Dong-jiao; LIU Yue-qin; SONG Xin; HUANG Yuan-tian

    2006-01-01

    The application of the vertical hoisting jack and wave motion compensation techniques to the salvage of an ancient sunken boat is introduced. The boat is wooden, loaded with cultural relics. It has been immersed at the bottom of the South China Sea for more than 800 years. In order to protect the structure of the boat and the cultural relics inside to the largest extent, an open caisson is used to hold the sunken boat and the silts around before they are raised from the seabed all together as a whole. In the paper, first, the seakeeping model test of the system of the salvage barge and the open caisson is done to determine some important wave response parameters. And then a further experimental study of the application of the vertical hoisting jack and wave motion compensation scheme to the salvage of the sunken boat is carried out. In the model tests, the techniques of the integrative mechanic-electronic-hydraulic control, wave motion forecast and wave motion compensation are used to minimize the heave motion of the open caisson. The results of the model tests show that the heave motion of the open caisson can be reduced effectively by the use of the present method.

  14. [The high-pressure chemistry, barophysiological chemistry, comparative enzymology of cholinesterase the 100th anniversary from the birth of A. P. Brestkin].

    Science.gov (United States)

    Rozengart, E V

    2012-01-01

    There are exposed the main landmarks of the scientific biography of Professor Aleksandr Pavlovich Brestkin, connected with his investigations in the field of chemistry of high pressures, physiological chemistry of caisson disease, kinetics of esterase catalysis, and in comparative enzymology of cholinesterases.

  15. Wave Forces on Transition Pieces for Bucket Foundations for Offshore Wind Turbines

    DEFF Research Database (Denmark)

    Nezhentseva, Anastasia; Andersen, Thomas Lykke; Andersen, Lars Vabbersgaard;

    to a bucket foundation (suction caisson) located at 35 m water depth in the North Sea. Several models of the TPs (wedge-shaped steel flange-reinforced shear panels, conical and doubly curved with or without cutaways) are tested in a wave flume and compared with respect to wave loading. Due to a larger size...

  16. Osteonecrosis (Avascular Necrosis)

    Science.gov (United States)

    ... cancer, SLE, blood disorders such as sickle cell disease, HIV infection, Gaucher’s disease, and Caisson disease. Who Is Likely to Develop ... pelvis, is the most common site of osteonecrosis. Gaucher’s disease. A congenital disease in which there is accumulation ...

  17. SWEEP Project RAT

    DEFF Research Database (Denmark)

    Ibsen, Lars Bo; Madsen, Søren; Roesen, Hanne Ravn

    In this report the design basis for the geotechnical design of the suction caisson at the K15-FA-1 location is described. The derived design soil parameters are based on the site specific CPTs conducted autumn 2010 by Wintershall Nederlands B.V. (Wintershall Netherlands B.V. and Noordhoek Survey B...

  18. SWEEP Project RAT

    DEFF Research Database (Denmark)

    Ibsen, Lars Bo; Madsen, Søren; Petersen, L. B.

    This report presents the results from the design analyses made for the clustered suction caisson used as foundation for a Riser Access Tower (RAT). The RAT is intended built next to the K15-FA-1 Platform in the Dutch Sector of the North Sea....

  19. Drained Response of Bucket Foundations under Cyclic Lateral Load

    DEFF Research Database (Denmark)

    Foglia, Aligi; Ibsen, Lars Bo

    2013-01-01

    Introduction The monopod bucket foundation is an innovative support structure for offshore wind turbines. It consists of a shallow embedded foundation which penetrates the seabed by means of a suction created within the caisson. The behaviour of bucket foundations against long-term lateral cyclic...

  20. Test of Gravel to South Leg - Siri Platform

    DEFF Research Database (Denmark)

    Thomassen, Kristina; Ibsen, Lars Bo

    A grout connection between one of the legs of the offshore platform, Siri, and a water caisson at the seabed is failed. The failure leaves a gap in the grout connection meaning that the stiffness of the connection is disappeared resulting in movements of the platform. These movements cause cracks...

  1. Application of lumped-parameter models

    DEFF Research Database (Denmark)

    Ibsen, Lars Bo; Liingaard, Morten

    This technical report concerns the lumped-parameter models for a suction caisson with a ratio between skirt length and foundation diameter equal to 1/2, embedded into an viscoelastic soil. The models are presented for three different values of the shear modulus of the subsoil (section 1.1). Subse...

  2. An Annotated Bibliography of Patents Related to Coastal Engineering. Volume I. 1967-1970. Appendix.

    Science.gov (United States)

    1979-11-01

    PREVENTION OF BEACH EROSION AND ENCOURAGE:’ ELT OF LAND RESTORATION 3344612 SHALLOW WATER CAISSON 34476u FLOATING EODY 334U867 BOTTO! BRACE FOR PILE HAMPER...Smulders. Schiedam. Netberlands fi- Ict ; 17, iYO.4, Set. No..4Sio,ud4 Clims priority, application Netherlands, May 15, 1964, 64-5,45g 3 Claims. (CI

  3. Investigation of seepage around the bucket skirt during installation in sand

    DEFF Research Database (Denmark)

    Koteras, Aleksandra Katarzyna; Ibsen, Lars Bo

    pressure that will create piping channels at exit, which is near to seabed and to the caisson wall, along bucket wall and at the tip. That is how the limits for suction installation can be assumed. Finally, the critical suction is used for predicting the reduction of penetration resistance and the method...

  4. 77 FR 112 - Effluent Limitations Guidelines and Standards for the Construction and Development Point Source...

    Science.gov (United States)

    2012-01-03

    ... included non-numeric requirements to: Implement erosion and sediment controls; Stabilize soils; Manage..., water from culvert sites and caissons at bridge construction sites that was impounded in a baffled... (grab sample, flow or time-weighted composite, continuous turbidity measurement, etc.);...

  5. On the Choice of Structure and Layout of Rubble Mound Breakwater Heads

    DEFF Research Database (Denmark)

    Maciñeira, Enrique; Burcharth, Hans F.

    2006-01-01

     The paper discusses the various functional, environmental and structural conditions to consider related to the choice of breakwater head type. Results from hydraulic model tests of rubble mound and caisson head solutions for the new deep water port at Punto Langosteira, La Coruña, Spain, are pre...

  6. Development and Testing of Techniques for In-Ground Stabilization, Size Reduction and Safe Removal of Radioactive Wastes Stored in Large Containments in Burial Grounds - 13591

    Energy Technology Data Exchange (ETDEWEB)

    Halliwell, Stephen [VJ Technologies Inc, 89 Carlough Road, Bohemia, NY (United States)

    2013-07-01

    Radioactive waste materials, including Transuranic (TRU) wastes from laboratories have been stored below ground in large containments at a number of sites in the US DOE Complex, and at nuclear sites in Europe. These containments are generally referred to as caissons or shafts. The containments are in a range of sizes and depths below grade. The caissons at the DOE's Hanford site are cylindrical, of the order of 2,500 mm in diameter, 3,050 mm in height and are buried about 6,000 mm below grade. One type of caisson is made out of corrugated pipe, whereas others are made of concrete with standard re-bar. However, the larger shafts in the UK are of the order of 4,600 mm in diameter, 53,500 mm deep, and 12,000 below grade. This paper describes the R and D work and testing activities performed to date to evaluate the concept of in-ground size reduction and stabilization of the contents of large containments similar to those at Hanford. In practice, the height of the Test Facility provided for a test cell that was approximately 22' deep. That prevented a 'full scale mockup' test in the sense that the Hanford Caisson configuration would be an identical replication. Therefore, the project was conducted in two phases. The first phase tested a simulated Caisson with surrogate contents, and part of a Chute section, and the second phase tested a full chute section. These tests were performed at VJ Technologies Test Facility located in East Haven, CT, as part of the Proof of Design Concept program for studying the feasibility of an in-situ grout/grind/mix/stabilize technology for the remediation of four caissons at the 618-11 Burial Ground at US Department of Energy Hanford Site. The test site was constructed such that multiple testing areas were provided for the evaluation of various tools, equipment and procedures under conditions that simulated the Hanford site, with representative soils and layout dimensions. (authors)

  7. Displacement of Monolithic Rubble-Mound Breakwater Crown-Walls

    DEFF Research Database (Denmark)

    Nørgaard, Jørgen Harck; Andersen, Lars Vabbersgaard; Andersen, Thomas Lykke

    2012-01-01

    studies on caisson breakwaters, but correction terms are suggested in the present paper to obtain almost equal measured and estimated displacements. This is of great practical importance since many existing rubble-mound crown-walls are subjected to increasing wave loads due to rising sea water level from......This paper evaluates the validity of a simple one-dimensional dynamic analysis as well as a Finite-Element model to determine the sliding of a rubble-mound breakwater crown-wall. The evaluation is based on a case example with real wave load time-series and displacements measured from two...... of the accumulated sliding distance of crown-wall superstructures, which is in contrast to findings from previous similar studies on caisson breakwaters. The calculated sliding distance is approximately three times larger than the measured one when using the original one-dimensional model suggested in previous...

  8. Embedment Effects on the Vertical Bearing Capacity of Offshore Bucket Foundations on Cohesionless Soil

    DEFF Research Database (Denmark)

    Barari, Amin; Ibsen, Lars Bo; Ghalesari, Abbasali Taghavi;

    2016-01-01

    This paper presents the results from a series of physical modeling and three-dimensional finite 9 element (FE) analyses, which examined the uniaxial vertical capacity of suction caissons for 10 offshore wind turbines. The experiments were carried out in quartz sand and involved monotonic 11 appli...... and FE analyses, new expressions for depth factor of shallow foundations have 15 been validated for embedment ratios (aspect ratios) up to unity, calibrating the fitting parameters 16 by employing data from a range of soil profiles....... application of vertical load. It was found that the drained capacity of suction caissons is 12 dependent on embedment ratio. On the other hand, predictions from conventional semi-empirical 13 depth factors were found to somewhat underestimate when applied to rough foundations. On the 14 basis of the tests...

  9. Prototype bucket foundation for wind turbines - natural frequency estimation

    Energy Technology Data Exchange (ETDEWEB)

    Ibsen, Lars Bo; Liingaard, M.

    2006-12-15

    The first full scale prototype bucket foundation for wind turbines has been installed in October 2002 at Aalborg University offshore test facility in Frederikshavn, Denmark. The suction caisson and the wind turbine have been equipped with an online monitoring system, consisting of 15 accelerometers and a real-time data-acquisition system. The report concerns the in service performance of the wind turbine, with focus on estimation of the natural frequencies of the structure/foundation. The natural frequencies are initially estimated by means of experimental Output-only Modal analysis. The experimental estimates are then compared with numerical simulations of the suction caisson foundation and the wind turbine. The numerical model consists of a finite element section for the wind turbine tower and nacelle. The soil-structure interaction of the soil-foundation section is modelled by lumped-parameter models capable of simulating dynamic frequency dependent behaviour of the structure-foundation system. (au)

  10. Prototype bucket foundation for wind turbines

    DEFF Research Database (Denmark)

    Ibsen, Lars Bo; Liingaard, Morten

    The first full scale prototype bucket foundation for wind turbines has been installed in October 2002 at Aalborg University offshore test facility in Frederikshavn, Denmark. The suction caisson and the wind turbine have been equipped with an online monitoring system, consisting of 15 accelerometers...... and a real-time data-acquisition system. The report concerns the in service performance of the wind turbine, with focus on estimation of the natural frequencies of the structure/foundation. The natural frequencies are initially estimated by means of experimental Output-only Modal analysis. The experimental...... estimates are then compared with numerical simulations of the suction caisson foundation and the wind turbine. The numerical model consists of a finite element section for the wind turbine tower and nacelle. The soil-structure interaction of the soil-foundation section is modelled by lumped-parameter models...

  11. Methode de Calcul du Flutter en Presence de jeu Mecanique et Verification Experimentale (Flutter Analysis Method in Presence of Mechanical Play and Experimental Verification)

    Science.gov (United States)

    2000-05-01

    structuraux du controle actif et flexible des aeronefs] To order the complete compilation report, use: ADA388195 The component part is provided here to...fibres optiques, de 84 d’un facteur 2 capteurs de pression, ainsi que de deux: potentiom~tres pour mesurer la rotation de la Cette confrontation a...gouverne caisson * palette d’excitation * encastrement au mur * 250 capteurs ( pression, jauge, acc~l6romnbtre, fibre optique) guen7 gouverne dispositif de

  12. Prototype bucket foundation for wind turbines:natural frequency estimation

    OpenAIRE

    Ibsen, Lars Bo; Liingaard, Morten

    2006-01-01

    The first full scale prototype bucket foundation for wind turbines has been installed in October 2002 at Aalborg University offshore test facility in Frederikshavn, Denmark. The suction caisson and the wind turbine have been equipped with an online monitoring system, consisting of 15 accelerometers and a real-time data-acquisition system. The report concerns the in service performance of the wind turbine, with focus on estimation of the natural frequencies of the structure/foundation. The nat...

  13. Condition Assessment Survey (CAS) Program. Deficiency standards and inspections methods manual: Volume 1, 0.01 Foundations and footings

    Energy Technology Data Exchange (ETDEWEB)

    1993-05-01

    General information is presented for asset determinant factor/CAS repair codes/CAS cost factors; guide sheet tool & material listing; testing methods; inspection frequency; standard system design life tables; system work breakdown structure; and general system/material data. Deficiency standards and inspection methods are given for footings - spread/strip/grade beams; foundation walls; foundation dampproofing/waterproofing; excavation/backfill/ and piles & caissons.

  14. The Shock and Vibration Digest. Volume 14, Number 11

    Science.gov (United States)

    1982-11-01

    Soil Mechanics Information and Analysis Center The SMIAC is staffed by a director and one other (SMIAC) is located at the U.S. Army Engineer Water ...An auger construction is provided which reduces the surface include references to caissons, railway ballast , and pipeline noise radiated by the auger...chord (0.3m) and constant thick- fication of the helicopter model by least-squared-error or ness 116%) supercritical wing. This study provided extensive

  15. Structural Optimization of an Offshore Wind Turbines Transition Pieces for Bucket Foundations

    OpenAIRE

    Nezhentseva, Anastasia; Andersen, Lars Vabbersgaard; Ibsen, Lars Bo; Sørensen, Eigil V.

    2011-01-01

    Traditionally, offshore constructions are made of steel. The focus of this paper is optimization of a transition piece (TP) connecting the offshore wind turbine column with a suction bucket foundation. Suction caissons, typically used for shallow water depths, have been proved to be adequate in residual soil conditions for depths up to approximately 40 m. The existing design practice is limited to the use of steel-flange-reinforced shear panels. Desirable outcome is proposal of an alternative...

  16. A Review of Coastal Navigation Asset Management Initiatives Within the Coastal Inlets Research Program (CIRP). Part 1: Coastal Structures

    Science.gov (United States)

    2010-08-01

    maintained by USACE. The vast majority of these is rubble mound or laid stone structures, but there are other types as well such as timber cribs and...pilings, sheetpile walls, cribs , and bulkheads, and poured concrete pilings and caissons. In terms of function, the coastal structures inventory...and injury reports (e.g. deaths , injuries, missing persons) and includes geo- coordinates for most entries. CSMART reads these data and performs a

  17. The Pathophysiology of Decompression Sickness and the Effects of Doppler Detectable Bubbles.

    Science.gov (United States)

    1980-12-18

    recent past. Before the work of the French physiologist Paul Bert in 1893, it was generally believed that decompression sickness or "Caisson Workers...platelet clumping has also recently been implicated ( Philp , 1974). Hemoconcentration has I also been suggested as an important factor in altitude...emboli (Barthelemy, 1963; Philp , et al., 1967; Crockett, et al., 1968). In spite of the other hypotheses proposed, the "bubble hypothesis" is believed

  18. Application of lumped-parameter models

    Energy Technology Data Exchange (ETDEWEB)

    Ibsen, Lars Bo; Liingaard, M.

    2006-12-15

    This technical report concerns the lumped-parameter models for a suction caisson with a ratio between skirt length and foundation diameter equal to 1/2, embedded into an viscoelastic soil. The models are presented for three different values of the shear modulus of the subsoil. Subsequently, the assembly of the dynamic stiffness matrix for the foundation is considered, and the solution for obtaining the steady state response, when using lumped-parameter models is given. (au)

  19. Construction safety in DOE. Part 2, Students guide

    Energy Technology Data Exchange (ETDEWEB)

    Handwerk, E.C.

    1993-08-01

    This report is the second part of a compilation of safety standards for construction activities on DOE facilities. This report covers the following areas: floor and wall openings; cranes, derricks, hoists, elevators, and conveyors; motor vehicles, mechanized equipment, and marine operations; excavations; concrete and masonry construction; steel erection; underground construction, caisson, cofferdams, and compressed air; demolition; blasting and the use of explosives; power transmission and distribution; rollover protective structures, overhead protection; and ladders.

  20. Characterization of 618-11 solid waste burial ground, disposed waste, and description of the waste generating facilities

    Energy Technology Data Exchange (ETDEWEB)

    Hladek, K.L.

    1997-10-07

    The 618-11 (Wye or 318-11) burial ground received transuranic (TRTJ) and mixed fission solid waste from March 9, 1962, through October 2, 1962. It was then closed for 11 months so additional burial facilities could be added. The burial ground was reopened on September 16, 1963, and continued operating until it was closed permanently on December 31, 1967. The burial ground received wastes from all of the 300 Area radioactive material handling facilities. The purpose of this document is to characterize the 618-11 solid waste burial ground by describing the site, burial practices, the disposed wastes, and the waste generating facilities. This document provides information showing that kilogram quantities of plutonium were disposed to the drum storage units and caissons, making them transuranic (TRU). Also, kilogram quantities of plutonium and other TRU wastes were disposed to the three trenches, which were previously thought to contain non-TRU wastes. The site burial facilities (trenches, caissons, and drum storage units) should be classified as TRU and the site plutonium inventory maintained at five kilograms. Other fissile wastes were also disposed to the site. Additionally, thousands of curies of mixed fission products were also disposed to the trenches, caissons, and drum storage units. Most of the fission products have decayed over several half-lives, and are at more tolerable levels. Of greater concern, because of their release potential, are TRU radionuclides, Pu-238, Pu-240, and Np-237. TRU radionuclides also included slightly enriched 0.95 and 1.25% U-231 from N-Reactor fuel, which add to the fissile content. The 618-11 burial ground is located approximately 100 meters due west of Washington Nuclear Plant No. 2. The burial ground consists of three trenches, approximately 900 feet long, 25 feet deep, and 50 feet wide, running east-west. The trenches constitute 75% of the site area. There are 50 drum storage units (five 55-gallon steel drums welded together

  1. Buckling Analysis of Bucket Foundations for Wind Turbines in Deep Water

    DEFF Research Database (Denmark)

    Madsen, Søren; Andersen, Lars; Ibsen, Lars Bo

    2011-01-01

    Using large suction caissons for offshore wind turbines is an upcoming technology also referred to as bucket foundations. The bucket foundation does not require heavy installation equipment, but since it is constructed as a thin steel shell structure, instability, in form of buckling, becomes...... a crucial issue during installation. This paper addresses the hydrostatic buckling pressure of the bucket foundation using threedimensional, non-linear finite element analysis. The main finding of this paper is that introducing an imperfect geometry based on the first linear pre-buckling mode shape, can...... increase the buckling load significantly....

  2. A case of aseptic vertebral necrosis in the context of metastatic lumbar disease

    Energy Technology Data Exchange (ETDEWEB)

    Panow, C. [Radiologie Florissant, Geneva (Switzerland); Valavanis, A. [Institut fuer Neuroradiologie, Universitaetsspital Zuerich (Switzerland)

    2002-03-01

    Aseptic bone necrosis has many well recognized etiologies: caisson disease, corticosteroids, alcohol, Gaucher's disease and sickle cell anemia being a few of a long list. Little attention has been paid to metastatic disease as a possible cause and we were unable to find reference in the literature to this association. We present imaging features of metastatic Ewing's sarcoma involving the vertebral spine, which, in certain aspects, mimics other well-known entities of this region, such as Kuemmell's and Scheuermann's diseases. (orig.)

  3. Horizontal Coherence of Wave Forces on Vertical Wall Breakwaters

    DEFF Research Database (Denmark)

    Archetti, R.; Frigaard, Peter; Lamberti, A.;

    2001-01-01

    Spatial coherence of wave impact pressures at a vertical breakwater in multidirectional seas is studied as part of an EU project under the LSF‐TMR programme. The lay out and programme of tests are shortly described. A method for the identification of breaking waves is presented. The percentage...... of breaking waves for increasing wave height are estimated and compared with existing empirical formulae. The horizontal dimension of the breaker is investigated using two different methodologies: the first analyses the decreasing of the highest 1/250 force with increasing horizontal dimension of the caisson...

  4. Simplified method for the frequency analysis of offshore structures with inclined members; Methode simplifiee pour l`analyse dynamique en frequence des structures offshore a membres inclines

    Energy Technology Data Exchange (ETDEWEB)

    Genatios, C.; Lafuente, M.; Garces, F. [Universidad Central de Venezuela, IMME, Caracas (Venezuela); Ferrante, A. [Universidade Federal do Rio de Janeiro, COPPE (Brazil)

    1998-12-01

    This paper presents a simplified procedure for the deterministic dynamic analysis of offshore structures with inclined members in the frequency domain. This simplified procedure requires the linearization of the velocity term of the Morison formula. A direct time integration method is implemented in the time domain, in order to verify the efficiency of the frequency domain procedure and the consequences of the involved simplifications. Three typical structures: a caisson, a steel jacket and a reinforced concrete lacustrine structure, are analyzed. Linearization of the velocity term, leads to more conservative results with a maximal error of 15 % for the three analyzed structures. (authors) 19 refs.

  5. Hydraulic Characteristics of Seawave Slot-cone Generator Pilot Plant at Kvitsøy (Norway)

    DEFF Research Database (Denmark)

    Margheritini, Lucia; Vicinanza, Diego; Kofoed, Jens Peter

    2007-01-01

    This paper presents results on wave overtopping and loading on an innovative caisson breakwater for electricity production. The work reported here contributes to the European Union FP6 priority 6.1 (Sustainable Energy System). The design of the structure consists of three reservoirs one on the top...... in a second phase the model has been adapted and equipped with pumps to measure the overtopping flow rates in the single reservoirs. The results of the tests highlight differences between 2D and 3D conditions in terms of pressures and hydraulic efficiency....

  6. Reliability Evaluation of Monolithic Vertical Wall Breakwaters Considering Impulsive Wave Breaking Forces and Failure Modes of the Foundation

    DEFF Research Database (Denmark)

    Burcharth, H. F.; Sørensen, Jørgen S.; Christiani, E.

    1994-01-01

    Impulsive wave breaking forces on a vertical caisson breakwater has been included by Takahashi et al, (1994) in Goda's wave pressure formula (Goda et al. 1972 and Goda 1974). Based on these formulae a deterministic design method following the Japanese recommendations has been used for the design ...... stability analysis is presented by the example of a rotation slip failure involving kinematically correct slip surfaces and failure zones in undrained clay. A conventional static quasi-static analysis based on equating external and internal work is used....

  7. CISM course on mechanical behaviour of soils under environmentally induced cyclic loads

    CERN Document Server

    Wood, David; Mechanical Behaviour of Soils Under Environmentally Induced Cyclic Loads

    2012-01-01

    The book gives a comprehensive description of the mechanical response of soils (granular and cohesive materials) under cyclic loading. It provides the geotechnical engineer with the theoretical and analytical tools necessary for the evaluation of settlements developng with time under cyclic, einvironmentally idncued loads (such as wave motion, wind actions, water table level variation) and their consequences for the serviceability and durability of structures such as the shallow or deep foundations used in offshore engineering, caisson beakwaters, ballast and airport pavements and also to interpret monitoring data, obtained from both natural and artificial slopes and earth embankments, for the purposes of risk assessment and mitigation.

  8. History of Military Psychology at the U. S. Naval Submarine Medical Research Laboratory

    Science.gov (United States)

    1979-10-23

    sickness ( nitrogen narcosis or rapture of the deep) as well as decompression sickness (bends or Caisson’s disease). The second example was a research...decrements in 3 divers exposed for 11. days to a helium/oxygen/ nitrogen "mix" In a pressure chamber at 7 times normal pressure (3. 37). Tending to...oxygen/ nitrogen atmosphere for 284 hours, 1964. AD 457909 4. NSMRL - The Second Decade of the Nuclear Submarine Era •1965-1975) 4.1 1965-1968 4. 11

  9. Port Adriano, 2D-Model tests

    DEFF Research Database (Denmark)

    Burcharth, Hans F.; Meinert, Palle; Andersen, Thomas Lykke

    the crown wall have been measured. The model has been subjected to irregular waves corresponding to typical conditions offshore from the intended prototype location. Characteristic situations have been video recorded. The stability of the toe has been investigated. The wave-generated forces on the caisson...... and the crown have been recorded. The maximum of horizontal wave force and the related tilting moment together with the pressure distribution are documented for waves in the range of design conditions. The parameters and results in the report are given in full-scale values, if nothing else is stated....

  10. A rational methodology for the study of foundations for marine structures; Una metdologia racional para el estudio de cimentaciones de estructuras marinas

    Energy Technology Data Exchange (ETDEWEB)

    Mira Mc Willams, P.; Fernandez-Merodo, J. A.; Pastor Perez, M.; Monte Saez, J. L.; Martinez Santamaria, J. M.; Cuellar Mirasol, V.; Martin Baanante, M. E.; Rodriguez Sanchez-Arevalo, I; Lopez Maldonando, J. D.; Tomas Sampedro, A.

    2011-07-01

    A methodology for the study of marine foundations is presented. The response in displacements, stresses and pore water pressures in obtained from a finite element coupled formulation. Loads due to wave action of the foundation are obtained from a volume of fluid type fluid-structure interaction numerical model. Additionally, the methodology includes a Generalized Plasticity based constitutive model for granular materials capable of representing liquefaction fenomena of sands subjected to cyclic loading, such as those frequently appearing in the problems studied. Calibration of this model requires a series of laboratory tests detailed herein. This methodology is applied to the study of the response of a caisson breakwater foundation. (Author) 10 refs.

  11. Stability of the Guiding Dike in Yangtze Estuary Under the Wave Load

    Institute of Scientific and Technical Information of China (English)

    YAN Shu-wang; LIU Run; FAN Qi-jin; XIE Shi-leng

    2005-01-01

    During the construction of the guiding dike in the Yangtze Estuary, some of the caisson structures sank into the soil for 1~5 m or slid about 20 m away from the original place when a strong storm attacked this area. Dynamic triaxial tests were carried out to simulate the behavior of foundation soils under wave loading. The test results show that the excessive settlement and lateral movement of the caissons are due to the weakening of the soft clay strength during the strong storm. The test results also show that the ability of the soft clay to resist the wave force will be greatly increased when the soft soil samples are suitably improved. Based on the test results, an improvement method combining vertical drains with surcharge loading was proposed to strengthen the foundation soil. On the improved soil foundation, the dike has been reconstructed and undergone several strong storms without any damage. A finite element approach has been developed for analyzing the settlement and stability of the dike under the action of strong storm.

  12. Leaching of solutes from ion-exchange resins buried in Bandelier Tuff

    Energy Technology Data Exchange (ETDEWEB)

    Essington, E.H.; Fuentes, H.R.; Polzer, W.L.; Lopez, E.A.; Stallings, E.A.

    1986-10-01

    Prediction of solute transport at shallow land burial facilities requires a knowledge of the rates of release of solutes (source term) from the buried wastes and of those processes affecting transport through the surrounding media. The leaching (removal) of lithium, strontium, and cesium from a resin/tuff mixture (Bandelier Tuff) was conducted under unsaturated steady and unsteady (drainage) flow conditions in both laboratory columns and large-scale field caissons to approximate the conditions of buried contaminated-waste resins. Lithium was leached most rapidly and strontium least rapidly. Stopping the flow for a period of 40 to 60 days to create drainage (unsteady flow) conditions had very little effect on the concentrations of solutes leached from the resin/tuff layer. Leaching of these solutes in laboratory columns simulated the large-scale (caisson) leaching very well. Thus, laboratory studies may be reasonable predictors of leaching under certain large-scale field conditions. Also, leaching appears to be a kinetics-controlled process that, for the experimental conditions of this study, may be represented by simple first-order kinetics. Further work should concentrate on understanding the effect of environmental factors such as solute mixtures, concentrations, and temperature, as well as those mechanisms that control leaching of solutes. Also, the evaluation and development of alternative mathematical models for describing the source term are needed.

  13. Riverbed Pre-Protection Techniques for Main Pier No .29 of Main Ship Channel Bridge of Hutong Changjiang River Bridge%沪通长江大桥主航道桥 29 号主墩河床预防护技术

    Institute of Scientific and Technical Information of China (English)

    崔一兵

    2015-01-01

    The main ship channel bridge of the Hutong Changjiang River Bridge is a double-py-lon continuous steel truss girder cable-stayed bridge with span arrangement (140+462+1 092+462+140) m .The foundation for the main pier No .29 of the bridge is the open caisson ,the di-mensions of the caisson top are 86 .9 m × 58 .7 m and the caisson height is 115 m .Because the silty sand stratum at the pier is deep and the stratum is prone to scouring under the action of water cur-rent ,the local scouring of the riverbed at the pier in the process of landing the caisson onto the ri-verbed can be severe .To ensure that the caisson could be stably and safely landed onto the river-bed ,the riverbed was hence pre-protected .The pre-protection system for the riverbed included the inverted filter layer ,protection layer and prism structure ,respectively composed of the 1~6 mm , 3~10 cm and 6~10 cm grading crushed stones and the riprapping depth is respectively 1 ,1 and 2 m ,of which the riprapping range of the protection layer extended 25 m outwards from the caisson wall .At the time the riverbed was pre-protected by the riprapping ,the virtual grids were deter-mined according to the riprapping tests ,the positioning barge ,grab barge ,material hoppers and ducts were all used to riprap at the fixed points .The inverted filter layer was riprapped first ,the protection lay was then and the prism structure was finally .With the application of the riverbed pre-protection technique ,the protection effect of the riverbed at the pier was evident and after the caisson was landed onto the riverbed and positioned ,the plan position and posture of the caisson almost had no changes .%沪通长江大桥主航道桥为(140+462+1 092+462+140 ) m双塔连续钢桁梁斜拉桥 , 29号主墩采用沉井基础 ,沉井顶平面尺寸为86 .9 m × 58 .7 m、高115 m.由于29号主墩位处粉砂层较厚 ,水流作用下这部分泥砂易被冲刷 ,对沉井着床过程中的局部冲刷大 ,为

  14. 某船坞坞口围堰设计及其止水技术%Water-stop Techniques and Design of Dock Cofferdam

    Institute of Scientific and Technical Information of China (English)

    杨新才; 王俐

    2015-01-01

    结合某船坞坞口围堰设计采用重力式沉箱结构型式的特点,通过在沉箱内预埋无缝钢管作为注浆管,利用旋喷施工工艺,使浆液和水玻璃在切割范围更好地与地层颗粒掺合,在地基中形成强度较高的连续固结体,起到加固防渗的作用,可供类似工程借鉴。%Gravity caisson structure applied to the design of one dock cofferdam, in which seamless steel pipes were pre-embedded in caisson as the grouting tube, jet grouting technology was used to improve the mixture of cement slurry, sodium silicate and soil granule within the effective range. Then high strength consolidated soil body was formed to reinforce the foundation and prevent it from seepage, which served as a reference for similar projects.

  15. Evaluation of Elevated Tritium Levels in Groundwater Downgradient from the 618-11 Burial Ground Phase I Investigations

    Energy Technology Data Exchange (ETDEWEB)

    Dresel, P.E.; Smith, R.M.; Williams, B.A.; Thompson, C.J.; Evans, J.C.; Hulstrom, L.C.

    2000-05-01

    This report describes the results of the preliminary investigation of elevated tritium in groundwater discovered near the 618-11 burial ground, located in the eastern part of the Hanford Site. Tritium in one well downgradient of the burial ground was detected at levels up to 8,140,000 pCi/L. The 618-11 burial ground received a variety of radioactive waste from the 300 Area between 1962 and 1967. The burial ground covers 3.5 hectare (8.6 acre) and contains trenches, large diameter caissons, and vertical pipe storage units. The burial ground was stabilized with a native sediment covering. The Energy Northwest reactor complex was constructed immediately east of the burial ground.

  16. Development of technology for the design of shallow land burial facilities at arid sites

    Science.gov (United States)

    Nyhan, J. W.; Abeele, W. V.; Drennon, B. J.; Herrera, W. J.; Lopez, E. A.; Langhorst, G. J.; Stallings, E. A.; Walker, R. D.; Martinez, J. L.

    The Los Alamos field research program involving technology development for arid shallow land burial (SLB) sites is described. Field data are presented for an integrated field experiment, which was designed to test individual SLB component experiments related to erosion control, biobarriers, and subsurface capillary and migration barriers. Field tests of biointrusion barriers at waste disposal sites and in experimental plots are reported. The results of a joint DOE/NRC experiment to evaluate leaching and transport of sorbing (Cs, Sr, Li) and nonsorbing (I, Br) solutes in sandy silt backfill are presented for steady-state and unsteady-state flow conditions. A capillary barrier experiment performed in a large caisson (3-m diameter, 6.1 m deep) is described and a year's worth of field data is presented.

  17. Development of technology for the design of shallow land burial facilities at arid sites

    Energy Technology Data Exchange (ETDEWEB)

    Nyhan, J.W.; Abeele, W.V.; Drennon, B.J.; Herrera, W.J.; Lopez, E.A.; Langhorst, G.J.; Stallings, E.A.; Walker, R.D.; Martinez, J.L.

    1985-01-01

    The Los Alamos field research program involving technology development for arid shallow land burial (SLB) sites is described. Field data are presented for an integrated field experiment, which was designed to test individual SLB component experiments related to erosion control, biobarriers, and subsurface capillary and migration barriers. Field tests of biointrusion barriers at waste disposal sites and in experimental plots are reported. The results of a joint DOE/NRC experiment to evaluate leaching and transport of sorbing (Cs, Sr, Li) and nonsorbing (I, Br) solutes in sandy silt backfill are presented for steady-state and unsteady-state flow conditions. A capillary barrier experiment performed in a large caisson (3-m diameter, 6.1 m deep) is described and a year's worth of field data is presented.

  18. Investigations on the porous media equations and resistance coefficients for coastal structures

    DEFF Research Database (Denmark)

    Jensen, Bjarne; Jacobsen, Niels Gjøl; Christensen, Erik Damgaard

    2014-01-01

    previously found in the literature. Constant values for the resistance coefficients for a broad range of flow conditions were recommended based on the new calibrations. The model was validated for the main physical processes that occur in wave–structure interaction in coastal structures including three...... some shortcomings which were identified. The applied type of porosity models relies on empirical resistance coefficients which often need to be measured or calibrated. Only few examples of calibration for numerical models which are present in the literature often applied the same experimental results......-dimensional wave–structure interaction, run-up, run-down and pressure damping, regular and irregular wave conditions and evaluation of overtopping. Simple two and three dimensional uniform caisson structures and breakwater layouts were investigated. The model was implemented in the open source CFD library Open...

  19. Investigation of seepage around the bucket skirt during installation in sand

    DEFF Research Database (Denmark)

    Koteras, Aleksandra Katarzyna; Ibsen, Lars Bo

    First aim of this study is to evaluate a pore pressure factor, . The factor describes the ratio between the excess pore pressure generated on the bucket tip and the applied suction under the bucket lid. The pore pressure factor can be then used for prediction of excess pore pressure at the tip...... or along bucket skirt with known soil condition, bucket geometry and applied suction. The second aim of the study is to evaluate expressions for normalized seepage length, s/h, for different soil combinations and penetration depths. The seepage length is then 7 used to make a prediction of critical...... pressure that will create piping channels at exit, which is near to seabed and to the caisson wall, along bucket wall and at the tip. That is how the limits for suction installation can be assumed. Finally, the critical suction is used for predicting the reduction of penetration resistance and the method...

  20. The potential role of perfluorocarbon emulsions in decompression illness.

    Science.gov (United States)

    Spiess, Bruce D

    2010-03-01

    Decompression illness (DCI) is an occasional occurrence in sport, professional, and military diving as well as a potential catastrophe in high-altitude flight, space exploration, mining, and caisson bridge construction. DCI theoretically could be a success-limiting problem in escape from a disabled submarine (DISSUB). Perfluorocarbon emulsions (PFCs) have previously been investigated as 'blood substitutes' with one approved by the United States Food and Drug Administration for the treatment of myocardial ischaemia. PFCs possess enhanced (as compared to plasma) respiratory gas solubility characteristics, including oxygen, nitrogen and carbon dioxide. This review examines approximately 30 years of research regarding the utilization of PFCs in gas embolism as well as experimental DCI. To date, no humans have been treated with PFCs for DCI.

  1. Radiation measurements in the reactors G 2 and G 3; Mesures de rayonnement aupres des piles G 2 - G 3

    Energy Technology Data Exchange (ETDEWEB)

    Chassany, J.Ph.; Estournel, R. [Commissariat a l' Energie Atomique, Centre de Production de Plutonium, Marcoule (France). Centre d' Etudes Nucleaires

    1964-07-01

    The results are given of numerous radiation measurements: - for the various working sites - for the various zones (circuit room,etc) - during the discharging operations - far various active materials (CO{sub 2}, plugs etc). They show that in general the protection has been suitably designed and that the majority of radio-protection problems are due to the elements activated in the pile and transported outside the vessel. (authors) [French] Les resultats de nombreuses mesures d'irradiation sont donnes - pour les differents lieux de travail - pour diverses zones (salle de tuyauteries, etc.) - pendant les operations de dechargement - pour differents materiaux actives (CO{sub 2}, bouchons, etc.) Ils montrent que les protections ont ete en general correctement dimensionnees et que la majorite des problemes de radioprotection est constituee par les elements actives dans la pile, transportes a l'exterieur du caisson. (auteurs)

  2. Corrosion protection of Arctic offshore structures: Final report. [Effects of temperature and salinity on required cathodic protection current

    Energy Technology Data Exchange (ETDEWEB)

    Sackinger, W.M.; Rogers, J.C.; Feyk, C.; Theuveny, B.

    1985-10-01

    Results are presented for a research program on corrosion prevention for Arctic offshore structures which are in contact with sea ice for a significant portion of the year. The electrical method most adaptable for structure protection involves the injection of impressed current from several remote anodes buried just beneath the sea floor. The electrical resistivity of annual sea ice as a function of temperature and salinity is presented. Details of the interface layers formed between sea ice and steel in the presence of current injection are shown. A computer program was developed to enable the calculation of protective current density into the structure, in the presence of ice rubble and ridges around the structure. The program and the results of an example calculation are given for a caisson- retained island structure. 81 refs., 103 figs., 3 tabs.

  3. On the instability of offshore foundations: theory and mechanism

    Science.gov (United States)

    Gao, FuPing; Li, JinHui; Qi, WenGang; Hu, Cun

    2015-12-01

    As the offshore engineering moving from shallow to deep waters, the foundation types for fixed and floating platforms have been gradually evolving to minimize engineering costs and structural risks in the harsh offshore environments. Particular focus of this paper is on the foundation instability and its failure mechanisms as well as the relevant theory advances for the prevailing foundation types in both shallow and deep water depths. Piles, spudcans, gravity bases, suction caissons, and plate anchors are detailed in this paper. The failure phenomena and mechanisms for each type of foundations are identified and summarized, respectively. The theoretical approaches along with sophisticated empirical solutions for the bearing capacity problems are then presented. The major challenges are from flow-structure-soil coupling processes, rigorous constitutive modeling of cyclic behaviors of marine sediments, and the spatial variability of soil properties for large-spreading structures. Further researches are suggested to reveal the instability mechanisms for underpinning the evolution of offshore foundations.

  4. Structural Optimization of an Offshore Wind Turbines Transition Pieces for Bucket Foundations

    DEFF Research Database (Denmark)

    Nezhentseva, Anastasia; Andersen, Lars Vabbersgaard; Ibsen, Lars Bo

    as an alternative to steel. CRC has an excellent durability and higher compressive strength compared to traditional concrete. This material has also an increased ductility owing to integration of large contents of short, strong and stiff steel fibres. At present, application of high-tension concrete is limited......Traditionally, offshore constructions are made of steel. The focus of this paper is optimization of a transition piece (TP) connecting the offshore wind turbine column with a suction bucket foundation. Suction caissons, typically used for shallow water depths, have been proved to be adequate...... offshore, mainly, to making a grouting connection of a transition piece to a monopile. Lack of standards and norms puts additional restriction on application of CRC. In the earlier work, the structural performance of transition pieces with a conical shape was compared for a 5 MW offshore wind turbine...

  5. The force of oblique incident wave on the breakwater with a partially perforated wall

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Wave forces induced by the interaction between the oblique incident wave and the breakwater with a partially perforated front wall is investigated. The fluid domain is divided into two sub-domains and the eigen-function expansion method is applied to expanding velocity potentials in each domain. In the eigen-expansion of the velocity potential, evanescent waves are included. Numerical results of the present model are compared with other theories and a good agreement can be found between them. Experimental data have been compared with the present theoretical results. The effect of the traverse wall on wave forces has been discussed in detail. On the basis of the linear wave theory, it is shown that in the range of engineering practice, the incident angle of wave has small influence on wave forces on the unit length of perforated caisson.

  6. Working mechanism and numerical simulation of assembly coastal building techniques

    Institute of Scientific and Technical Information of China (English)

    陈育民; 刘汉龙; 陈泽

    2008-01-01

    A new coastal technique, named as assembly coastal building, was introduced. The main concept of the technique was the assembling components which could be combined and locked together to form a large caisson. The assembly coastal building technique was used in a sea access road in Zhuanghai 4X1 well, Dagang Oilfield. The design plans and in-situ tests in the sea access road project were introduced in detail. According to the Zhuanghai project, the numerical simulation method of assembly coastal building technique was proposed. 2D numerical simulations were performed in FLAC to analyze the displacement and stability of the technique in the construction process and post-construction period. The settlement calculated is close to the in-situ results, which proves that the proposed numerical method is reasonable. Results show that the assembly coastal building technique has large safety factor under the gravity loading and wave loadings.

  7. Reliability Analysis of Geotechnical Failure Modes for Vertical Wall Breakwaters

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Burcharth, H. F.

    2000-01-01

    Vertical wall breakwaters are usually designed as concrete caissons placed on the top of a rubble mound foundation or a rubble bedding layer. The purpose of the breakwater is usually to protect the area behind the breakwater from being flooded by large waves. The area protected can for example be...... that the accepted probability of failure also varies considerably which also can be observed from the actual observed failure rates....... be a harbour of small or large importance, an important industrial area or a heavily populated coast line. This implies that vertical wall breakwaters are used under quite different conditions and therefore the consequences of a complete or partial failure also are very different. This implies...

  8. Lumped-parameter Model of a Bucket Foundation

    DEFF Research Database (Denmark)

    Andersen, Lars; Ibsen, Lars Bo; Liingaard, Morten

    2009-01-01

    efficient model that can be applied in aero-elastic codes for fast evaluation of the dynamic structural response of wind turbines. The target solutions, utilised for calibration of the lumped-parameter models, are obtained by a coupled finite-element/boundaryelement scheme in the frequency domain......, and the quality of the models are tested in the time and frequency domains. It is found that precise results are achieved by lumped-parameter models with two to four internal degrees of freedom per displacement or rotation of the foundation. Further, coupling between the horizontal sliding and rocking cannot...... be disregarded without significant loss of accuracy. Finally, special attention is drawn to the influence of the skirt stiffness, i.e. whether the embedded part of the caisson is rigid or flexible....

  9. Modeling study of solute transport in the unsaturated zone: Workshop proceedings

    Energy Technology Data Exchange (ETDEWEB)

    Springer, E.P.; Fuentes, H.R. (eds.)

    1987-04-01

    Issues addressed were the adequacy of the data for the various models, effectiveness of the models to represent the data, particular information provided by the models, the role of caisson experiments in providing fundamental knowledge of porous-media water flow and solute transport, and the importance of geochemistry to the transport of nonconservative tracers. These proceedings include the presentations made by each of the modelers; the summary document written by the panel; and a transcript of the discussions, both the discussions that followed individual presentations and the general discussion held on the second day. This publication completes the series on the workshop. Volume I in the series (NUREG/CR-4615, Vol. I) contains background information and the data sets provided each modeler.

  10. 大桥深水基础方案设计与施工及经济性研究%Study of Design Solutions, Construction and Economy of Deepwater Foundations for Major Bridges

    Institute of Scientific and Technical Information of China (English)

    杨进

    2011-01-01

    大桥深水基础方案设计在技术上如能很好地与环境相适应,可以达到经济上更合理,现以2座大桥基础工程实例进行分析.肇庆西江公铁两用大桥水中4号墩基础外形与高承台管柱基础基本相似,采用全钢外壳,由于在施工中无需承受震动打桩机的强力冲击,所以结构截面比较轻型,用钢量并不高,且有相当一部分系使用后可以回收的常备式杆件,故在经济上更具优势而且工期也短.泰州长江公路大桥中塔沉井基础高76 m,分为12节,沉井平面布置12个大井孔,与当时在长江中习惯采用的大直径深钻孔集群桩基础方案相比,该沉井基础在材料上更节省,工艺上更简单,且在受力性能和经济性方面明显占优,具有明显的技术优势.%If the design solutions of deepwater foundations for major bridges can technically accommodate very well the environment where the foundations are located, the solutions will be economically still more rational. The practical examples of the foundations of two major bridges are cited herewith and analyzed. The outline of the foundation for in-water Pier No. 4 of Zhaoqing Xijiang River Rail-cum-Road Bridge, used with complete steel shell, is basically similar to the foundation of the cylindrical shafts with elevated pier base. The structural cross section of the foundation for the pier is rather light and the usage amount of steel is not great because the foundation does not have to sustain strong impact from vibro-pile driver in the construction and moreover, a considerable part of the common members for the foundation is recyclable after usage and the foundation therefore is economically advantageous and the working time schedule is short as well. The caisson foundation, 76 m in height, for intermediate tower of Taizhou Changjiang River Highway Bridge is composed of 12 lifts and has 12 big wells arranged in plan of the caisson. In comparison to the large diameter and deep hole group

  11. Utilizing geological and geotechnical parameters to constrain optimal siting of Mid-Atlantic Bight offshore wind projects

    Science.gov (United States)

    Ponte, Alia

    As the offshore wind energy sector expands due to government mandates, a thorough understanding of the geologic setting of potential project sites becomes an essential component in the design process. Geophysical and geotechnical parameters yield vital information on the sediments and/or rocks that are present. The variable distribution of sediments, with concomitant variations in geotechnical properties, has significant implications for the selection (e.g., monopile, suction caisson, gravity base, jacket), design, location, installation, and subsequent scouring in the vicinity of wind turbine foundations. Identifying suitable sites based on sediment types allow for optimized engineering design solutions. Because foundations represent approximately 25% of total offshore wind project expenditures, reducing foundation costs with geologic suitability in mind could significantly decrease required initial investments, thereby expediting project and industry advancement. To illustrate how geological and geotechnical data can be used to inform site selection for foundations, geophysical data were analyzed and interpreted (chirp sub-bottom profiling, side-scan sonar, and multibeam bathymetry) from the Maryland Wind Energy Area (WEA). Side-scan sonar data from the WEA show three distinct acoustic intensities; each is correlated to a general bottom sediment grain size classification (muds, muddy and/or shelly sand, and sand with some gravel). Chirp sub-bottom profiles reveal the continuity and thicknesses of various depositional layers including paleochannel systems. Paleochannels consist of heterogeneous infill; creating undesirable conditions for foundation placement. This "desktop" study provides a suitability model for how the interpretation of geophysical and geotechnical data can be used to provide constraints on, and reduce uncertainties associated with, foundation location and type selection. Results from this study revealed 5 distinct subsurface units. The oldest

  12. El puente Bendorf sobre el Rin (Alemania

    Directory of Open Access Journals (Sweden)

    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

  13. Floating type ocean wave power station equipped with hydroelectric unit

    Science.gov (United States)

    Okamoto, Shun; Kanemoto, Toshiaki; Umekage, Toshihiko

    2013-10-01

    The authors have invented the unique ocean wave power station, which is composed of the floating type platform with a pair of the floats lining up at the interval of one wave pitch and the counter-rotating type wave power unit, its runners are submerged in the seawater at the middle position of the platform. Such profiles make the flow velocity at the runner is twice faster than that of the traditional fixed/caisson type OWC, on the ideal flow conditions. Besides, the runners counter-rotate the inner and the outer armatures of the peculiar generator, respectively, and the relative rotational speed is also twice faster than the speed of the single runner/armature. Such characteristics make the runner diameter large, namely the output higher, as requested, because the torque of the power unit never act on the floating type platform. At the preliminary reseach, this paper verifies to get the power using a Wells type single runner installed in the model station. The runner takes the output which is affected by the oscillating amplitude of the platform, the rotational speed and the inertia force of the runner, etc.

  14. Development of new construction technology; Seko shin gijutsu no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Ikemura, M.

    1994-07-10

    Recent trend in construction technology employed in the construction industry is presented. Continuous underground wall method, shield pipe jacking method, and concrete bridge erection method have been developed. In the field of pneumatic caisson method, remote control for stereoscopic vision with a 3D camera and remotely operated recovery of drilling machine are being employed. In the case of the RCD method, remotely operated green cut device has been introduced for labor saving. For the shield tunneling method, technological development for larger cross section and modified cross section has been carried on actively as well as development for labor-saving and unmanned controlling. Development of direction control in small diameter pipe jacking method is in progress. NATM method is a typical construction method for mountain tunnels. Technology to learn the area and the amount of soil has been developed wherein photographic surveying and GPS are used for rapid work progress measurement. Development of rationalization technology for construction, automations of works, and rationalization technology for construction plan control are outlined. 23 refs., 4 tabs.

  15. G2 - G3 inventive properties, the first french nuclear plants; Caracteristiques generales et aspects originaux des reacteurs G2 et G3

    Energy Technology Data Exchange (ETDEWEB)

    Pascal; Horowitz; Bussac; Joatton; De Lagge de Meux; Martin [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1958-07-01

    This paper points out the inventive properties of the frenchctors G2 and G3. These are dual purpose reactors, i.e. designed for the production of both plutonium and energy (30 electrical MW); in this respect, they can be considered as the start point of the french electrical energy produced from nuclear fuel. The following points are specially discussed in this paper: the choice of the prestressed concrete pressure vessel, the horizontal arrangement of the channels, the interest of neutron flux flattening, the advantages of the charging and discharging device working during pile operation. (author)Fren. [French] Les caracteres originaux des reacteurs fran is G2 et G3 sont decrits dans ce rapport. Ce sont des reacteurs a double fin, plutonigenes et aussi producteurs d'energie (30 MW electriques); ils constituent a ce titre le point de depart de la production fran ise d'electricite d'origine nucleaire. Sont discutes, en particulier, dans ce rapport: le choix du caisson en beton precontraint pour tenir la pression, la disposition horizontale des canaux, l'interet de l'aplatissement du flux neutronique, les avantages de l'appareil permettant le chargement et le dechargement du combustible sans arreter la pile. (auteur)

  16. 重力式码头抛石基床掏空的诊断、处理和预警

    Institute of Scientific and Technical Information of China (English)

    万涛; 邵成

    2015-01-01

    Based on the actual example in the project, we discuss the diagnosis methods and reinforcement measures when rubble bed of gravity is damaged by water flow from tugboat's starting.The position and extent of damage of rubble bed can be diag-nosed through diving inspection and underwater topograghic survey and analysis the socuring trend of the wharf foundation.Combined with the engineering characteristics,wo putforward the scheme of building underwater unscattered concrete to fill cavity of caisson toe and integral pouring underwater concrete in the range of 3M.%结合工程实际,论述了重力式码头抛石基床在现阶段大马力拖轮螺旋桨高速水流作用下破损掏空后的检测方法和加固治理方法。通过水下潜水检查能得到基础破损空洞的部位和大小,并通过测量水底标高分析码头前沿基础存在的冲刷趋势,结合工程特点,提出浇筑水下不离析混凝土填充沉箱前趾下空洞,前沿3m范围内整体浇筑水下混凝土的加固方案。

  17. A study on the flow characteristics of a direct drive turbine for energy conversion generation by experiment and CFD

    Science.gov (United States)

    Cho, Y. J.; Zullah, M. A.; Faizal, M.; Choi, Y. D.; Lee, Y. H.

    2012-11-01

    A variety of technologies has been proposed to capture the energy from waves. Some of the more promising designs are undergoing demonstration testing at commercial scales. Due to the complexity of most offshore wave energy devices and their motion response in different sea states, physical tank tests are common practice for WEC design. Full scale tests are also necessary, but are expensive and only considered once the design has been optimized. Computational Fluid Dynamics (CFD) is now recognized as an important complement to traditional physical testing techniques in offshore engineering. Once properly calibrated and validated to the problem, CFD offers a high density of test data and results in a reasonable timescale to assist with design changes and improvements to the device. The purpose of this study is to investigate the performance of a newly developed direct drive hydro turbine (DDT), which will be built in a caisson for extraction of wave energy. Experiments and CFD analysis are conducted to clarify the turbine performance and internal flow characteristics. The results show that commercial CFD code can be applied successfully to the simulation of the wave motion in the water tank. The performance of the turbine for wave energy converter is studied continuously for a ongoing project.

  18. Study on Information Management for the Conservation of Traditional Chinese Architectural Heritage - 3d Modelling and Metadata Representation

    Science.gov (United States)

    Yen, Y. N.; Weng, K. H.; Huang, H. Y.

    2013-07-01

    After over 30 years of practise and development, Taiwan's architectural conservation field is moving rapidly into digitalization and its applications. Compared to modern buildings, traditional Chinese architecture has considerably more complex elements and forms. To document and digitize these unique heritages in their conservation lifecycle is a new and important issue. This article takes the caisson ceiling of the Taipei Confucius Temple, octagonal with 333 elements in 8 types, as a case study for digitization practise. The application of metadata representation and 3D modelling are the two key issues to discuss. Both Revit and SketchUp were appliedin this research to compare its effectiveness to metadata representation. Due to limitation of the Revit database, the final 3D models wasbuilt with SketchUp. The research found that, firstly, cultural heritage databasesmustconvey that while many elements are similar in appearance, they are unique in value; although 3D simulations help the general understanding of architectural heritage, software such as Revit and SketchUp, at this stage, could onlybe used tomodel basic visual representations, and is ineffective indocumenting additional critical data ofindividually unique elements. Secondly, when establishing conservation lifecycle information for application in management systems, a full and detailed presentation of the metadata must also be implemented; the existing applications of BIM in managing conservation lifecycles are still insufficient. Results of the research recommends SketchUp as a tool for present modelling needs, and BIM for sharing data between users, but the implementation of metadata representation is of the utmost importance.

  19. On the Architectural Decoration of Fujian and Taiwan Ma Zu Temple%闽台妈祖宫庙建筑装饰探究

    Institute of Scientific and Technical Information of China (English)

    柯立红

    2012-01-01

    闽台妈祖宫庙装饰包括宫庙建筑内外的装饰和宫庙整体环境的装饰。闽台妈祖宫庙建筑装饰主要有木雕、石雕、砖雕、泥塑、剪瓷雕、交趾陶、水车垛、绘画、书法匾额等工艺技法。妈祖宫庙建筑还有牌楼、戏台、影壁、碑铭、须弥座、藻井等装饰,其中也包括了色彩的装饰,妈祖宫庙建筑装饰具有一定的精神内涵。%Fujian and Taiwan Ma Zu Temple's architectural decoration includes the interior and exterior and extends to the buildings surroundings. There are mainly carvings of woods & stones & bricks, clay sculpture, porce- lain carving, infrequent pottery, art of architecture, excellent painting, calligraphy etc. Ma Zu Temple is also built with its ancient ceremonial arches, stages, screens, inscriptions, Xu Mizuo, caisson and color decoration. Ma Zu Temple's decoration has certain spiritual intension.

  20. Radio-active pollution near natural uranium-graphite-gas reactors; La pollution radioactive aupres des piles uranium naturel - graphite - gaz

    Energy Technology Data Exchange (ETDEWEB)

    Chassany, J.; Pouthier, J.; Delmar, J. [Commissariat a l' Energie Atomique, Chusclan (France). Centre de Production de Plutonium de Marcoule

    1967-07-01

    The results of numerous evaluations of the contamination are given: - Reactors in operation during maintenance operations. - Reactors shut-down during typical repair operations (coolants, exchangers, interior of the vessel, etc. ) - Following incidents on the cooling circuit and can-rupture. They show that, except in particular cases, it is the activation products which dominate. Furthermore, after ten years operation, the points at which contamination liable to emit strong doses accumulates are very localized and the individual protective equipment has not had to be reinforced. (authors) [French] Les resultats de nombreuses evaluations de la contamination sont donnes: - Piles en marche pendant les operations d'entretien - Piles a l'arret au cours des chantiers caracteristiques (refrigerants, echangeurs, interieur du caisson, etc.) - A la suite d'incidents sur le circuit de refroidissement et de rupture de gaine. Ils montrent que, sauf cas particulier, ce sont essentiellement les produits d'activation qui dominent. Par ailleurs apres 10 ans de fonctionnement, les points d'accumulation de la contamination susceptibles de delivrer des debits de dose importants restent tres localises et les moyens de protection individuels utilises n'ont pas du etre renforces. (auteurs)

  1. Status of outdoor radioactive contamination at the Hanford Site

    Energy Technology Data Exchange (ETDEWEB)

    McKinney, S.M.; Markes, B.M.

    1994-12-01

    This document summarizes the status of outdoor radioactive contamination near Hanford Site facilities and disposal sites. It defines the nature and areal extend of the radioactively contaminated areas and describes the historical, ongoing, and planned radiological monitoring and control activities. Radioactive waste has been disposed of to the soil column since shortly after the reactors and production facilities began operating. Radioactive liquid wastes were placed directly into the ground via liquid discharges to cribs, ponds, ditches, and reverse wells. Solid wastes were placed in trenches, burial vaults, and caissons. Although the Hanford Site covers 1,450 km{sup 2}, the radioactively contaminated area is only about 36 km{sup 2} or 2.5% of the original site. Over time, contamination has migrated from some of the waste management sites through various vectors (e.g., burrowing animals, deep-rooted vegetation, erosion, containment system failure) or has been deposited to the surface soil via spills and unplanned releases (e.g., line leaks/breaks, tank leaks, and stack discharges) and created areas of outdoor radioactivity both on and below the surface. Currently 26 km{sup 2} are posted as surface contamination and 10 km{sup 2} are posted as underground contamination.

  2. 向海洋工程要经济效益

    Institute of Scientific and Technical Information of China (English)

    陈浩波; 赵彤

    2000-01-01

    Up to now, Dalian New Shipyard has completed more than 25 offshore projects for new constructions, repairing and convertion of jack-ups, semi-submersible low hulls, living quarters, drilling caisson and FPSO etc. both from the domestic and world market. By taking advantage of its dry dock in 355m(L)×80m(W)×12.7m(D)equipped with a 900t gantry crane and other advanced equipment available, Dalian New Shipyard becomes very competitive and competent for all typed offshore projects in the world market. Besides, Xingang Shipyard,Beihai Shipyard and Shanhaiguan Shipyard in north China are also active in offshore projects for the construction and repairing of accommodation, self-walking drilling platform, man-made island for shallow water oil field, jack-ups as well as the VLCC tanker convertion. All these projects have helped the shipyards to upgrade their technical levels for further offshore projects and establish good records to participate in bidding competition in offshore market.

  3. Health and efficiency in trimix versus air breathing in compressed air workers.

    Science.gov (United States)

    Van Rees Vellinga, T P; Verhoeven, A C; Van Dijk, F J H; Sterk, W

    2006-01-01

    The Western Scheldt Tunneling Project in the Netherlands provided a unique opportunity to evaluate the effects of trimix usage on the health of compressed air workers and the efficiency of the project. Data analysis addressed 318 exposures to compressed air at 3.9-4.4 bar gauge and 52 exposures to trimix (25% oxygen, 25% helium, and 50% nitrogen) at 4.6-4.8 bar gauge. Results revealed three incidents of decompression sickness all of which involved the use of compressed air. During exposure to compressed air, the effects of nitrogen narcosis were manifested in operational errors and increased fatigue among the workers. When using trimix, less effort was required for breathing, and mandatory decompression times for stays of a specific duration and maximum depth were considerably shorter. We conclude that it might be rational--for both medical and operational reasons--to use breathing gases with lower nitrogen fractions (e.g., trimix) for deep-caisson work at pressures exceeding 3 bar gauge, although definitive studies are needed.

  4. Experimental analysis of 7.62 mm hydrodynamic ram in containers

    Science.gov (United States)

    Deletombe, E.; Fabis, J.; Dupas, J.; Mortier, J. M.

    2013-02-01

    The design of fuel tanks with a reduced vulnerability with respect to hydrodynamic ram pressure (HRAM) effects is of an increasing need in the Civil (e.g. the Concorde accident), and Defence (military aircraft, unmanned vehicle systems) aircraft industries. The presented work concerns experimental research which aims at observing two hydraulic ram events - both induced by a 7.62 mm bullet shot in very different containers - throughout their various steps until the final collapse of the generated cavity, in order to study the nature of HRAM, the influence of the containers geometry, and to measure original dynamic data for numerical modelling developments and validation. For that purpose, test configurations and experimental results are described, documented and discussed. They concern two types of firing tests that were performed at ONERA using the NATO 7.62 mm projectile, respectively in the frame of ONERA (pool) and EUCLID (caisson) funded research projects. The authors concentrate on two topics: on the one hand, digital image analysis to measure the cavity geometry during its growth and collapse phases and, on the other hand, pressure measurements that catch the transient shock wave. The originality of the work consists in the fact that - compared with other published works - the phenomenon is studied up to tens of milliseconds in a very large pool for theoretical analysis of the bullet/liquid interactions only, and in a realistic fuel tank specimen to consider influence of boundary conditions onto the cavity characteristics (geometry, dynamics).

  5. Pedestal-type understructure and an electric heat recovery system make Boston office building high achiever in land use and energy conservation

    Energy Technology Data Exchange (ETDEWEB)

    1976-01-01

    Land use and energy conservation goals are responsible for the unusual pedestal base of Boston's new Fiduciary Trust Building, located in one of the city's oldest sections. The area surrounding South Station and designated for renewal is plagued with a complex traffic situation on the surface and an underground maze of utility lines and conduits and subway tunnels, all of which combined to make innovative construction necessary. Caissons that by-pass underground obstructions support vertical steelwork through a flaring three-story pedestal. Cantilevered trusses provide a platform for the tower floors and allow versatile use of space with esthetically pleasing lines. An original glass-face plan was replaced with 35 percent tinted glass, 20 percent insulation-backed glass, and 45 percent precast concrete in order to conserve energy. Individualized lighting control was accomplished by installing 1000 wall switches to control the 3000 fixtures. Standardized 35-watt four-foot fluorescent tubes and a High Voltage Alternating Current (HVAC) air system allow further energy savings. A stringent new building code is credited with inspiring many of the conservation features. Details of the construction and heat recovery systems include a design summary of the building's construction specifications. (DCK)

  6. Exercises in Heavy Lowering

    CERN Multimedia

    2006-01-01

    Driving up to Point 5, one can't help but notice the impressively enormous red structure climbing up and over Building 3585. This unusual bridge-like construction is CMS'new crane, otherwise known as 'the gantry'. CMS'impressive "gantry" was recently installed at Building 3585. The 'gantry'was constructed by VSL, a Swiss company that is used to building such uniquely designed cranes used for major construction jobs, including lifting the roofs of various stadiums and the huge Airbus A380 assembly hall in Toulouse or bridge foundation caissons. CMS's crane was custom-built to sustain up to 2000 tonnes of machinery and detectors and slowly lower them down into the experimental cavern. The feature of two towers, one on either side of the building, each 24 m high, is the reason behind the nickname of this amazing crane. Two large beams, 28 m long and 3.4 m high, run along the width of the roof and four openings, each 5 m long, in the ceiling will allow the cables to pass through into the gallery. Unlike typic...

  7. Analytical study on aseismic base isolation in new offshore location. For practical location for thermal power plants by soft-landing artificial ground construction method; Atarashii kaijo ricchi ni okeru menshinsei ni kansuru kaisekiteki kento. Nanchaku jinko jiban koho ni yoru karyoku hatsuden setsubi ricchi jitsuyoka ni mukete

    Energy Technology Data Exchange (ETDEWEB)

    Kawamura, T.; Sakakibara, T. [Tokyo Electric Power Co. Inc., Tokyo (Japan); Ishikawa, M. [Nikken Sekkei Ltd., Osaka (Japan)

    1996-09-05

    Assuming offshore location of thermal power plants by soft-landing artificial ground construction method, its effect on uneven settlement of facility unit group and its seismic behavior were studied. In soft-landing artificial ground, the total weight and buoyancy of a caisson body with interior space are balanced by controlling water level in a tank to reduce landing pressure. Artificial ground resists lateral seismic external force by friction with submarine bedrock. Settlement analysis and seismic behavior analysis were conducted by 2-D FEM. As a result, bottom RC honeycomb structure was sufficient to resist uneven settlement during construction even under fixed junction condition between units. In soft-landing artificial ground, the maximum acceleration was reduced to nearly 70% by aseismic base isolation as compared with conventional methods. In addition, its sliding manner in earthquake was different from that of rigid bodies, and the maximum stress acceleration transmitted to the bottom of artificial ground changed even under the same waveform. 4 refs., 13 figs., 4 tabs.

  8. Circulatory bubble dynamics: from physical to biological aspects.

    Science.gov (United States)

    Papadopoulou, Virginie; Tang, Meng-Xing; Balestra, Costantino; Eckersley, Robert J; Karapantsios, Thodoris D

    2014-04-01

    Bubbles can form in the body during or after decompression from pressure exposures such as those undergone by scuba divers, astronauts, caisson and tunnel workers. Bubble growth and detachment physics then becomes significant in predicting and controlling the probability of these bubbles causing mechanical problems by blocking vessels, displacing tissues, or inducing an inflammatory cascade if they persist for too long in the body before being dissolved. By contrast to decompression induced bubbles whose site of initial formation and exact composition are debated, there are other instances of bubbles in the bloodstream which are well-defined. Gas emboli unwillingly introduced during surgical procedures and ultrasound microbubbles injected for use as contrast or drug delivery agents are therefore also discussed. After presenting the different ways that bubbles can end up in the human bloodstream, the general mathematical formalism related to the physics of bubble growth and detachment from decompression is reviewed. Bubble behavior in the bloodstream is then discussed, including bubble dissolution in blood, bubble rheology and biological interactions for the different cases of bubble and blood composition considered.

  9. Autopista Bilbao-Behobia España

    Directory of Open Access Journals (Sweden)

    Editorial, Equipo

    1978-11-01

    Full Text Available The construction of the Oyarzun-Behovia stretch of the Bilbao-Behovia motorway has meant the completion of this important means of communication in the Basque Country. Earth moving work has been of the order of 25 million cubic meters. The project includes 7 overpasses, 16 underpasses and three bridges. The structures have been built using poststresser light-weight slabs, reinforced caissons and poststressed girders with «reinforced earth work» abutments.

    La construcción del tramo Oyarzun-Behobia ha permitido finalizar la Autopista Bilbao-Behobia, importante realización para las comunicaciones en el País Vasco. Se ha hecho movimiento de tierras, del orden de los 25 millones de metros cúbicos. La obra consta de: - 7 pasos superiores, - 16 pasos inferiores, y - 3 puentes. Las estructuras han sido realizadas con losas aligeradas postensadas, cajones armados y vigas postensadas con estribos de «tierra armada».

  10. Results of the reactant sand-fracking pilot test and implications for the in situ remediation of chlorinated VOCs and metals in deep and fractured bedrock aquifers.

    Science.gov (United States)

    Marcus, D L; Bonds, C

    1999-08-12

    Permeable reactive barriers (PRBs), such as the Waterloo Funnel and Gate System, first implemented at Canadian Forces Borden facility in 1992, are a passive remediation technology capable of controlling the migration of, and treating contaminated groundwater in situ. Most of the PRBs installed to date have been shallow installations created by backfilling sheet-pile shored excavations with iron filing reactive media. More recently continuous trenchers [R. Puls, Installation of permeable reactive barriers using continuous trenching equipment, Proceedings of the RTDF Permeable Barriers Work Group, Virginia Beach, VA, September 1997] and Caissons [J. Vogan, Caisson installation of a pilot scale, permeable reactive barrier in situ treatment zone at the Sommersworth Landfill, NH, Presented to the RTDF Permeable Barriers Work Group, Alexandria, VA, April 1996], and vertical fracturing emplacements [G. Hocking, Vertical hydraulic fracture emplacement of permeable reactive barriers, Progress Report delivered to the Permeable Reactive Barriers Workgroup of the Remedial Technology Development Forum, Beaverton, OR, April 1998] have been used to create reactive barriers in soil. None of the prior methods are capable of adequately addressing groundwater contamination in deep and fractured bedrock aquifers. The purpose of the RSF pilot study was to install reactive media into an impacted bedrock aquifer, and to evaluate the effectiveness of in situ treatment of chlorinated volatile organic compounds (CVOCs) and metals in that type of aquifer. Three discrete fractures were identified and treated and were subjected to testing before and after treatment. Between 300 and 1700 lb. of 1 mm diameter reactive proppants were injected into each zone to facilitate treatment. Monitoring data obtained from adjacent observation wells verified that fracking fluids reached at least 42 ft from the treatment well following hydrofracturing. The concentrations of many of the CVOCs decreased up to

  11. Research on and Application of Undrained Strength Softening Model of Tianjin Soft Clay Under Cyclic Loading%循环荷载下天津软黏土不排水强度弱化模型研究及应用

    Institute of Scientific and Technical Information of China (English)

    王元战; 焉振

    2015-01-01

    strength softening model is applied to caisson structures lying on partly sand-backfilled soft foundations to analyze the settlement of the caisson. By comparison with static and pseudo-static models which ignore strength softening,the impact of strength softening of soft clay on struc-tural settlement is illustrated.

  12. 南京长江四桥北锚碇工程锚体及锚固系统施工技术%Construction Technology of Anchor and Anchor System for North Anchorage Engineering of the Fourth Nanjing Yangtze River Bridge

    Institute of Scientific and Technical Information of China (English)

    葛文璇; 徐贵娥; 陈静

    2012-01-01

    悬索桥的锚碇是一个十分重要的部位,以南京长江四桥北锚碇工程为背景,介绍了锚体及锚固系统的施工工艺.南京长江四桥锚碇锚固系统采用钢筋混凝土榫锚固系统,以提高结构的可靠性和耐久性.从锚体的分层分块、模板施工和混凝土浇筑工艺方面介绍了锚体施工工艺,并从锚固钢板的加工、起吊、安装、精确定位等方面介绍了锚固系统的施工工艺.%The anchorage caisson is a very important part of suspension bridge. The authors introduce the construction technology of anchor and anchor system of north anchorage of the Fourth Nanjing Yangtze River Bridge. The mortise-tenon anchor system of reinforced concrete is adopted in the anchor system of north anchorage of the Fourth Nanjing Yangtze River Bridge in order to improve its reliability and durability. The authors introduce the construction technology of anchor from anchor of hierarchical blocks, formwork and concrete pouring technique. From the anchor plate processing, hoisting, installation and precise positioning, the author introduce the construction technology of anchor system.

  13. Centro administrativo y de investigación de una compañía de seguros Viena – Austria

    Directory of Open Access Journals (Sweden)

    Hlaweniczka, Kurt

    1978-09-01

    Full Text Available This building is shaped in the form of a cross, with ten towers, six of which are 70 m high and the other four 45 m high. The most outstanding feature is their slender Steel, water-filled columns supporting the floor construction. The columns, in their turn rest on cross beams placed on box trusses (caisson connecting the towers. The towers were built using sliding forms, while the box trusses were built using scaffold forms. Infra-red rays were used in different construction stages to achieve the fast curing of the concrete. The building contains, among other areas, an electronic data processing facility, a teaching hall, mess hall, lounge, etc.

    Este edificio tiene forma de una cruz, con diez torres, cuatro de ellas con una altura de 70 m y las otras seis con una altura de 45 m. Su rasgo más característico son unas columnas delgadas de acero llenas de agua, sobre las que se apoyan los forjados de las plantas. Estas columnas, a su vez, se apoyan sobre vigas transversales colocadas sobre las vigas-cajón que unen las torres. Las torres fueron realizadas mediante encofrados deslizantes, mientras las vigas-cajón lo fueron con cimbras. En diversas fases de la construcción se utilizaron rayos ¡infrarrojos para conseguir un endurecimiento rápido del hormigón. El edificio consta de una instalación de elaboración electrónica de datos, una sala de enseñanza, comedor, sala de estar, etc.

  14. DESIGN, PERFORMANCE, AND SUSTAINABILITY OF ENGINEERED COVERS FOR URANIUM MILL TAILINGS

    Energy Technology Data Exchange (ETDEWEB)

    Waugh, W. Jody

    2004-04-21

    Final remedies at most uranium mill tailings sites include engineered covers designed to contain metals and radionuclides in the subsurface for hundreds of years. Early cover designs rely on compacted soil layers to limit water infiltration and release of radon, but some of these covers inadvertently created habitats for deep-rooted plants. Root intrusion and soil development increased the saturated hydraulic conductivity several orders of magnitude above design targets. These covers may require high levels of maintenance to sustain long-term performance. Relatively low precipitation, high potential evapotranspiration, and thick unsaturated soils favor long-term hydrologic isolation of buried waste at arid and semiarid sites. Later covers were designed to mimic this natural soil-water balance with the goal of sustaining performance with little or no maintenance. For example, the cover for the Monticello, Utah, Superfund site relies on a thick soil-sponge layer overlying a sand-and-gravel capillary barrier to store precipitation while plants are dormant and on native vegetation to dry the soil sponge during the growing season. Measurements of both off-site caisson lysimeters and a large 3-ha lysimeter built into the final cover show that drainage has been well below a U.S. Environmental Protection Agency target of less than 3.0 mm/yr. Our stewardship strategy combines monitoring precursors to failure, probabilistic riskbased modeling, and characterization of natural analogs to project performance of covers for a range of possible future environmental scenarios. Natural analogs are needed to understand how ecological processes will influence cover performance, processes that cannot be predicted with short-term monitoring and existing numerical models.

  15. Applications of the observational method in deep foundations

    Directory of Open Access Journals (Sweden)

    Fathi M. Abdrabbo

    2012-12-01

    Full Text Available The observational method was introduced into geotechnical engineering to improve both theories and construction techniques. This method was developed to avoid highly conservative assumptions about soil properties in geotechnical design when faced with unavoidable uncertainties of natural ground conditions. The assumptions involved in soil mechanics theories usually differ to a certain extent from reality. These assumptions can be improved by employing an observational database. Thus, theories of geotechnical engineering can be developed by observations during the construction stage. Moreover, precise management of construction work by close observations is essential to avoid risk and to alter the design if needed to match the real conditions. This paper sheds some light on the importance of the observational concept in deep foundations through three case studies. The first one demonstrates the effect of working hypotheses on design outputs of an open caisson of 22 m internal diameter. The other two case studies present the difference between theory and reality during construction stage of auger cast-in-place piles (ACIP in difficult subsoil conditions. Importance of merging the documented theories with the available observations is discussed. The study shows that working hypotheses and engineering models affect the cost and the time required for construction of deep foundations. Field observations are essential during installation of ACIP at a site. Some precautions should be considered when drilling ACIP through sandstone of inclined top surface. These precautions are mainly dependent upon field observations during construction. ACIP can be used effectively in soil formations that have galleries and caves using a cement–bentonite mixture to fill the holes of the unsuccessful piles. Finally, the paper shares a series of practical guidelines with engineering community all over the world that may assist in design and construction of deep

  16. Puente de hormigón pretensado sobre el rio Ulúa, Honduras

    Directory of Open Access Journals (Sweden)

    Editorial, Equipo

    1967-07-01

    Full Text Available In the course of an international competition, the Compagnie Française d'Entreprises has submitted two designs, and the one adopted is a cantilever box section type bridge, prestressed transversally and longitudinally and built by successive overhangs. The present article describes in considerable detail the above road bridge, of three spans, the two end ones being 60 m long, and the centre one is 120 m long. The two middle piles rest on caissons. The overhanging sections of the main span are each 42 m long, and the middle part of the span, which is simply supported on overhanging sections, is 36 m long. The bridge is now open to traffic and is a great aid to the communications network of Honduras.En concurso internacional, la Compagnie Française d'Entreprises presentó dos soluciones, adoptándose la de un puente, tipo cantilever, de sección en cajón, pretensado transversal y longitudinalmente y construido en voladizo. La obra que en este trabajo se describe con bastante detalle es un puente para carretera, de tres tramos, dos laterales de 60 m de luz y uno central de 120 m. Las dos pilas centrales se apoyan sobre cajones. Los brazos en voladizo tienen 42 m de longitud y la pieza central de cierre, simplemente apoyada sobre las extremidades de los citados brazos, una longitud de 36 metros. El puente se halla actualmente en servicio y constituye una gran mejora en la red vial hondureña.

  17. Landfill stabilization focus area: Technology summary

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-06-01

    Landfills within the DOE Complex as of 1990 are estimated to contain 3 million cubic meters of buried waste. The DOE facilities where the waste is predominantly located are at Hanford, the Savannah River Site (SRS), the Idaho National Engineering Laboratory (INEL), the Los Alamos National Laboratory (LANL), the Oak Ridge Reservation (ORR), the Nevada Test Site (NTS), and the Rocky Flats Plant (RFP). Landfills include buried waste, whether on pads or in trenches, sumps, ponds, pits, cribs, heaps and piles, auger holes, caissons, and sanitary landfills. Approximately half of all DOE buried waste was disposed of before 1970. Disposal regulations at that time permitted the commingling of various types of waste (i.e., transuranic, low-level radioactive, hazardous). As a result, much of the buried waste throughout the DOE Complex is presently believed to be contaminated with both hazardous and radioactive materials. DOE buried waste typically includes transuranic-contaminated radioactive waste (TRU), low-level radioactive waste (LLW), hazardous waste per 40 CFR 26 1, greater-than-class-C waste per CFR 61 55 (GTCC), mixed TRU waste, and mixed LLW. The mission of the Landfill Stabilization Focus Area is to develop, demonstrate, and deliver safer,more cost-effective and efficient technologies which satisfy DOE site needs for the remediation and management of landfills. The LSFA is structured into five technology areas to meet the landfill remediation and management needs across the DOE complex. These technology areas are: assessment, retrieval, treatment, containment, and stabilization. Technical tasks in each of these areas are reviewed.

  18. Nuclear reactor (1960); Reacteurs nucleaires (1960)

    Energy Technology Data Exchange (ETDEWEB)

    Maillard, M.L. [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires; Leo, M.B. [Electricite de France (EDF), 75 - Paris (France)

    1960-07-01

    The first French plutonium-making reactors G1, G2 and G3 built at Marcoule research center are linked to a power plant. The G1 electrical output does not offset the energy needed for operating this reactor. On the contrary, reactors G2 and G3 will each generate a net power of 25 to 30 MW, which will go into the EDF grid. This power is relatively small, but the information obtained from operation is great and will be helpful for starting up the power reactor EDF1, EDF2 and EDF3. The paper describes how, previous to any starting-up operation, the tests performed, especially those concerned with the power plant and the pressure vessel, have helped to bring the commissioning date closer. (author) [French] Les premiers reacteurs industriels plutonigenes francais G1 - G2 - G3 du Centre de Marcoule comportent une installation de recuperation d'energie. La production d'electricite de G1 ne compense pas l'energie depensee par ailleurs pour le fonctionnement de l'ensemble, par contre, G2 et G3 doivent fournir chacun une puissance de 25 a 30 MW au reseau national d'Electricite de France. Cette puissance est modeste, mais l'experience acquise grace a ces reacteurs est tres grande et c'est grace a elle qu'il nous sera possible de mettre en exploitation les reacteurs energetiques EDF1 - EDF2 - EDF3. Le memoire decrit comment, avant tout demarrage du reacteur, les essais effectues, en particulier ceux concernant l'installation de recuperation d'energie et le caisson, ont permis d'abreger la phase de montee en puissance. (auteur)

  19. Process of constructing a lightweight x-ray flight mirror assembly

    Science.gov (United States)

    McClelland, Ryan S.; Biskach, Michael P.; Chan, Kai-Wing; Espina, Rebecca A.; Hohl, Bruce R.; Saha, Timo T.; Zhang, William W.

    2014-07-01

    Lightweight and high resolution optics are needed for future space-based x-ray telescopes to achieve advances in highenergy astrophysics. NASA's Next Generation X-ray Optics (NGXO) project has made significant progress towards building such optics, both in terms of maturing the technology for spaceflight readiness and improving the angular resolution. Technology Development Modules (TDMs) holding three pairs of mirrors have been regularly and repeatedly integrated and tested both for optical performance and mechanical strength. X-ray test results have been improved over the past year from 10.3 arc-seconds Half Power Diameter (HPD) to 8.3 arc-seconds HPD. A vibration test has been completed to NASA standard verification levels showing the optics can survive launch and pointing towards improvements in strengthening the modules through redundant bonds. A Finite Element Analysis (FEA) study was completed which shows the mirror distortion caused by bonding is insensitive to the number of bonds. Next generation TDMs, which will demonstrate a lightweight structure and mount additional pairs of mirrors, have been designed and fabricated. The light weight of the module structure is achieved through the use of E-60 Beryllium Oxide metal matrix composite material. As the angular resolution of the development modules has improved, gravity distortion during horizontal x-ray testing has become a limiting factor. To address this issue, a facility capable of testing in the vertical orientation has been designed and planned. Test boring at the construction site suggest standard caisson construction methods can be utilized to install a subterranean vertical vacuum pipe. This facility will also allow for the testing of kinematically mounted mirror segments, which greatly reduces the effect of bonding displacements. A development platform demonstrating the feasibility of kinematically mounting mirror segments has been designed, fabricated, and successfully tested.

  20. Batch and column studies of adsorption of Li, Ni and Br by a reference sand for contaminant transport experiments

    Energy Technology Data Exchange (ETDEWEB)

    Seigel, M.D. [Sandia National Labs., Albuquerque, NM (United States); Ward, D.B.; Bryan, C.R. [Univ. of New Mexico, Albuquerque, NM (United States)] [and others

    1995-09-01

    A processed quartz sand (Wedron 510), mined from the St. Peter sandstone, has been characterized by a variety of chemical and physical methods for use as a reference porous media in transport model validation experiments. Wedron 510 sand was used in an intermediate-scale experiment involving migration of Ni, Li and Br through a 6-m high x 3-m diameter caisson. Ni and Li adsorption/desorption, and Li/Ni site-competition experiments yielded information on the importance of the trace mineral phases to adsorption of Li and Ni by the sand. The presence of an iron hydroxide coating similar to goethite on the sand grains is suggested by visual observation and leaching experiments. Kaolinite was identified by SEM and XRD as a significant trace mineral phase in the sand and occurs as small particles coating the sand grains. Quartz, the predominant constituent of the sand by weight, does not appear to contribute significantly to the adsorption properties of the sand. Qualitatively, the adsorption properties of the sand can be adequately modeled as a two-mineral system (goethite and kaolinite). The studies described in this report should provide a basis for understanding transport of Ni, Li and Br through porous media similar to the reference sand. Techniques were developed for obtaining parameter values for surface complexation and kinetic adsorption models for the sand and its mineral components. These constants can be used directly in coupled hydrogeochemical transport codes. The techniques should be useful for characterization of other natural materials and elements in high-level nuclear waste in support of coupled hydrogeochemical transport calculations for Yucca Mountain.

  1. Adaptaciones metodológicas en la aplicación del análisis estratigráfico constructivo: el Santuario de San Juan de la Penyagolosa (Castellón y la iglesia de San Juan de los Reyes en Granada

    Directory of Open Access Journals (Sweden)

    Mileto, Camilla

    2003-12-01

    Full Text Available This text presents two cases of the application of stratigraphic wall study in which two specific adaptations, stemming from the original case of the building analysed, were developed. In the first case, the study of the Santuario de San Juan de la Peñagolosa, the notable size of the shrine meant that data collection and management were highly complex. For this reason, a methodology was tested whereby information was hierarchized, allowing it to be managed faster and more efficiently. In the second case, the study of the church of San Juan de los Reyes, a complementary study was carried out in addition to the stratigraphic wall study. The same construction technique used in the building (wall stonework with brick buttresses and limestone boulder caissons brought about the possibility of carrying out a study of the distribution of the weep holes.En este texto se presentan dos casos de aplicación del estudio estratigráfico constructivo en los cuales se desarrollaron dos adaptaciones específicas ocasionadas por el caso concreto del edificio analizado. En el primer caso, el estudio del Santuario de San Juan de la Peñagolosa, la notable dimensión del conjunto conllevaba una complejidad de recogida y gestión de la información. Por esta razón, se ensayó una metodología de jerarquización de la información que permitiera una gestión de la misma más rápida y eficaz. En el segundo caso, el estudio de la iglesia de San Juan de los Reyes, además del estudio estratigráfico se realizó un estudio complementario. La misma técnica utilizada en el edificio (fábricas de machones de ladrillo y cajones de cantos rodados y cal sugirió la posibilidad de realizar el estudio del ritmo de la distribución de los mechinales.

  2. Puentes Santa María y Pantano, en la Autopista del Sol (Italia

    Directory of Open Access Journals (Sweden)

    Frizzi, Dorian

    1966-03-01

    Full Text Available Of all the constructional features along the 750 km of the Milan-Napoles motor road, only the two above mentioned bridges will be described. Both have have a large radius curvature in the horizontal plane, two independent pavements, and in both cases the deck is supported by a palisade of cylindrical columns, some of them very tall and of considerable diameter. The main spans are 40 m long, and the piles can reach a height of up to 40 m above their base. The foundations of these have necessitated the adoption of pneumatic caissons. The longest beams of the Santa Maria bridge are prestressed, concreted in the workshop and placed with the aid of auxiliary girders and travelling cranes, which lift them to their final emplacement. At the Fosso Pantano viaduct the girders were concreted at one end of the deck, and were then transported to their final position with the help of a provisional tubular framework. The beams rest either on led or neoprene plates, in order to provide suitable flexible joints.Entre todas las obras de fábrica, construidas a lo largo de los 750 km de esta autopista Milán-Nápoles, se describen aquí sólo los dos puentes enunciados. Ambos tienen su eje en curva circular de gran radio, dos calzadas independientes y soportes formando palizadas de montantes de fuste cilíndrico, algunas de gran diámetro y altura. Los tramos de mayor importancia son de 40 m de luz, y sus soportes ganan la mayor cota a unos 40 m de la base. Para los cimientos de estos últimos ha sido necesario el empleo de cajones neumáticos. Las vigas de mayor longitud en el puente de Santa María son de hormigón pretensado, hormigonadas en taller y lanzadas con vigas auxiliares, provistas de un puente-grúa para llevarlas a su posición definitiva. En el viaducto de Fosso Pantano, las vigas se hormigonaron en una extremidad del tablero y se riparon después hasta llevarlas a su posición definitiva, para lo cual se preparó previamente un entramado tubular

  3. Puente sobre el río Jarama, España

    Directory of Open Access Journals (Sweden)

    Rodríguez-Borlado, Ramiro

    1965-12-01

    Full Text Available As the previous bridge connecting Barajas with Paracuellos, on the 5th km of the road joining these villages, had been destroyed, a new one has been built. It is made of steel, has five spans, with a total length of 178.85 ms, has a 7 m wide pavement, and two 1.10 m wide sidewalks. The main feature of this bridge is a continuous girder, running over the three central spans, one 36.9 m long, and the other two 24.2 m each. This girder has a continuous web, of double T section. It has two halves, 6.2 ms apart, suitably linked together. The depth varies, and increases slightly over the central supports. The central piles rest on new foundations, consisting of caissons. The rest of the old foundations have been preserved. At the central pile the attachment is fixed, and on the two adjacent piles roller bearings have been fitted. At the end supports the deck structure rests on neoprene plates, 12 mm thick. To ensure the stability of the deck slab, a number of adequately spaced dilation joints have been provided.Por haber sido socavado y destruido el puente primitivo, situado en el punto kilométrico 4,800, y con objeto de restablecer el tráfico en la carretera de Barajas a Paracuellos, se ha construido uno nuevo, de estructura metálica, de cinco tramos, con una longitud total de 178,85 m, calzada de 7 m y dos andenes de 1,10 m de anchura cada uno. La parte principal de esta obra consiste en una viga continua que salva los tres tramos centrales, uno de 36,90 m de luz y los dos adyacentes a él de 24,20 m. Esta viga está constituida por dos de alma llena, de sección en forma de doble T, espaciadas a 6,20 m y convenientemente arriostradas entre ellas. Su canto es variable, aumentando linealmente en las proximidades de los dos apoyos centrales, hasta estos mismos. Las pilas de los tres tramos centrales se apoyan sobre nuevos cimientos, realizados con cajones, conservando los demás cimientos existentes. El apoyo sobre la pila central es fijo, y de

  4. FEM Analysis of Bearing Capacity of Bucket Foundation in the Cross-anisotropic Soft Soil%非均质软基上桶形基础承载性能有限元分析

    Institute of Scientific and Technical Information of China (English)

    武科; 马明月; 陈榕

    2011-01-01

    作为海洋平台的基础部分,桶形基础不仅承受海洋平台结构及自身重量等竖向荷载的长期作用,而且往往还遭受波浪等所产生的水平荷载及力矩等其它荷载分量的作用.因此,确定软基上桶形基础在竖向荷载(V)、水平荷载(H)和力矩(M)等共同作用下的承载特性,建立其在复合加载模式下的破坏包络面,并进而依此评价海洋平台基础及地基的稳定性,是桶形基础设计与施工中的关键问题.在大型通用有限元分析软件ABAQUS平台上,采用基于Mises屈服准则的完全弹塑性本构模型,对横现各向异性软基上桶形基础的承载性能进行了三维弹塑性数值分析,探讨了软黏土不排水抗剪强度的各向异性对单个荷载和复合加载作用下桶形基础承载性能的影响.%Bucket foundation is a new-type offshore foundation applicable especially for marginal field oil extraction, which is usually subjected to the simultaneous actions of both gravity and other environmental loads. Gravity loads act vertically while environmental loads induced by wave, wind and current are imposed laterally with both horizontal load and moment on the foundation. The responses of suction caisson foundation subjected to such a type of combined loads are therefore of great importance for the design and construction of offshore foundation. Three dimensional finite element numerical analyses are performed by using the general-purpose FEM package ABAQUS/Standard, in which the soil is assumed to obey the Mises's yield criterion. Both the stability or failure envelopes and collapse and working mechanism of suction bucket foundation founded in the crosy-anisotropic soil strata under undrained conditions subjected to monotonic loading or combined loading are discussed.

  5. Diseño y construcción de las bóvedas por cruceros en España durante el siglo XVI

    Directory of Open Access Journals (Sweden)

    Palacios, J. C.

    2013-10-01

    Full Text Available The aim of this text is to present the historical guidelines, design and construction of the grid crossing vaults built in Spain during the 16th century to show how the Gothic tradition of building ribbed vaults could be adapted to classical aesthetic principles. In the Andalusia of the 16th century, both a Renaissance classical architecture and another extraordinarily evolved Gothic one reached, at the same time, their full development, taking place between them interesting knowledge, stylistic and technical transfers. In this respect, the grid crossing vaults are a remarkable example of the formal autonomy of Gothic ribs which, without losing their medieval construction principles, are capable of adapting themselves to Renaissance models. We will see how in the grid crossing vaults, the Gothic crossings adapted themselves to the shape of a classical grid structure, drawing on the surface of the vault a design of caissons according to the stricter Roman Canon.El objetivo de este texto es dar a conocer las pautas históricas, de diseño y construcción de las bóvedas por cruceros erigidas en España durante el siglo XVI, como muestra de cómo la tradición gótica de construir bóvedas con nervaduras pudo adaptarse a los principios estéticos clásicos. En la Andalucía del siglo XVI, una arquitectura clásica renacentista y otra gótica extraordinariamente evolucionada alcanzaron, al mismo tiempo, su pleno desarrollo; entre ambas se produjeron interesantes transferencias de conocimiento, estilísticas y técnicas. En este sentido, las bóvedas por cruceros constituyen un notable ejemplo de autonomía formal de la nervadura gótica que, sin perder sus principios constructivos medievales, es capaz de adaptarse a modelos renacentistas. Veremos como en las bóvedas por cruceros, las crucerías góticas se adaptan a la forma de una trama reticular clásica, dibujando sobre la superficie de la bóveda un diseño de casetones conforme al canon

  6. Varios puentes de Berlín

    Directory of Open Access Journals (Sweden)

    Heusel, Hanns

    1963-03-01

    Full Text Available The last war destroyed a large number of civil works, among which were the Berlin bridges. As the number of these was considerable, it was decided to improve on the original designs and methods of construction, taking advantage of new materials and prestressing techniques. Of the 84 reconstructed bridges, 24 of them have been made in prestressed concrete. This emphasizes what considerable importance was attached to this constructional method at a time when this technology had not yet reached its present day mature development. The rebuilt bridges have spans varying between 25 and 100 ms. Their foundations differ considerably in each particular case. Some consist of pile structures, others are of sheet piling, and others again are caissons. At present the most important prestressed bridge in Berlin is the Disching bridge, which runs over the Havel, and carries the road to Spandau. Its single span is 94 ms long, and the ratio of rise to span is 1/63.1.La última guerra mundial destruyó una serie de obras públicas, entre las cuales se hallaban muchos puentes de Berlín. Como el número de puentes destruidos es considerable, se pensó en mejorar las obras originales y los métodos de construcción, para lo cual se contaban con nuevos materiales y la técnica del pretensado, actualmente en estado de madurez. De las 84 obras que se han reconstruido, 24 son de hormigón pretensado. Esto pone de relieve la importancia que se le dio a este sistema en aquellos momentos en que la técnica de este tipo de construcciones no había alcanzado todavía el actual desarrollo. Los puentes reconstruidos tienen luces que varían de 25 a 100 metros. Los cimientos de estas obras son muy distintos y variados: unos están formados por tablestacas, otros se apoyan sobre pilotes y, finalmente, otros, constituidos por cajones. El puente pretensado más importante actualmente en Berlín es el de Disching, que salva el río Havel y cuyo objeto es el de dar paso a la

  7. Nuevo puente de La Barca sobre el río Ter

    Directory of Open Access Journals (Sweden)

    Rodríguez-Borlado, Ramiro

    1967-12-01

    Full Text Available The new La Barca bridge, over the river Ter, is on the northern approach to Gerona, and carries the CN II road from Madrid to France, passing through Barcelona. It substitutes another bridge of the same name, which was inadequate for the heavy increase in traffic, during recent years. The bridge is 128 m long, consisting of two lateral spans, each 37 m long, and a central span of 54 m. The superstructure consists of ten hollow metal girders, of variable depth, arranged as three-part cantilevered structures. The lateral sections are cantilevered towards the centre, and the middle part of the span rests on their extremities. The girders support a reinforced concrete slab of 16 cm thickness and 14 m width: 8 m for the roadway, and 3 m for each of the sidewalks. The structure rests on two piles and two abutments of reinforced concrete, based on caisson foundations, except for one of the abutments, which is a reinforced concrete block. The project is completed by the approach roads and stonemasonry.El nuevo puente de La Barca, sobre el río Ter, está situado en el acceso norte a Gerona de la C. N. II de Madrid a Francia por Barcelona. Sustituye a otro del mismo nombre que resultaba insuficiente para la elevada intensidad de tráfico de esta vía. La luz del puente es de 128 m, dividida en dos tramos laterales, de 37 m de luz, y un tramo central, de 54 m. La superestructura está constituida por cinco vigas metálicas, huecas, de canto variable, dispuestas como vigas cantilever de tres elementos. Los elementos laterales se prolongan hacia el centro en voladizo, apoyándose sobre ellos el elemento central. Las vigas soportan una losa de hormigón armado de 16 cm de espesor, y 14 m de anchura: 8 m para la calzada y 3 m para cada uno de los andenes laterales. El conjunto se apoya sobre dos pilas y dos estribos, de hormigón armado, cimentados sobre cajones indios, excepto uno de los estribos, que está cimentado sobre macizo de hormigón armado

  8. A Long-Term Seismic Array on the Endeavour Segment of the Juan de Fuca Ridge

    Science.gov (United States)

    McGill, P. R.; Wilcock, W. S.; Stakes, D. S.; Barclay, A. H.; Ramirez, T. M.; Toomey, D. R.

    2003-12-01

    The Keck Foundation with additional support from the Monterey Bay Aquarium Research Institute and the University of Washington has funded a five-year, five-million dollar program for archetypic experiments on the northern Juan de Fuca Plate. The goal of this program is to constrain the linkages between deformation (earthquakes), fluid flow and chemistry, and microbial response across the northern Juan de Fuca Plate in the northeastern Pacific Ocean. A key component of these studies is an array of ocean-bottom seismometers to record the temporal and spatial distribution of seismic activity in the region. The current network, deployed in August of 2003, is comprised of eight autonomous instruments: one broadband seismometer and seven short-period seismometers. The instruments are distributed within and around the axial valley at the center of the Endeavour segment and spaced about 4 km apart, composing an array about 7 km wide and 9 km long. The short-period instruments, sensitive over a frequency range of 1 to 32 Hz, utilize an MBARI/GEOSense BH1 three-axis corehole geophone connected to an MBARI/GEOSense LP1 data logger. For five of these instruments the corehole sensor is inserted into a 7 cm diameter hole drilled into the basaltic basement rock, thus providing excellent coupling. For the other two instruments where suitable drilling sites were not available, the sensors are inserted into 55 kg concrete blocks placed on the sediment. The broadband instrument is a Guralp CMG-1T three-axis seismometer, sensitive over a frequency range of 2.8 mHz (360 sec) to 50 Hz. The sensor is completely buried in sediment inside a 60 cm deep by 60 cm diameter caisson, thus reducing the effects of water currents on the recorded data. A 20 m cable connects the sensor to an LP1 data logger and a 30 kW-hr battery sitting on the sediment. A complete data set will be recovered from the array when the instruments are revisited during the summer of 2004. However, data from two events, an

  9. 海洋油气开发用水下紧凑型多相分离技术%Underwater Compact Multiphase Separation Technology for Offshore Petroleum Development

    Institute of Scientific and Technical Information of China (English)

    李锐锋; 陈家庆; 姬宜朋; 李汉勇; 王春升

    2012-01-01

    The seafloor multistage separation technology is the key to the subsea oil and gas processing technology in offshore pe-troleum development as well as an important part of underwater production system. Distinguished international petroleum companies have attached great importance to the underwater compact multistage separation technology in recent years, developing some new underwater compact multistage separation technologies and equipments. The paper introduces the structure and operating principle of seabed vertical caisson separator, vertical vessel separator, horizontal single coil pipe separator and vertical multi-pipe separator. The history of devel-opment and the corresponding progress of engineering cases are also introduced. Part of the paper tocuses on the technological scheme for gas-liquid separation of produced fluid of oil well, which breaks the traditional thinking pattern in umltiphase separator design and provides the referenee for domestic researchers in independent development of the compact muhiphase separation technology.%海底多相分离技术是海洋油气开发中海底处理技术的核心,也是水下生产系统的重要组成部分。世界知名石油公司近年来非常重视水下紧凑型多相分离技术,研制开发了多种新型水下紧凑型多相分离技术和设备。介绍了海底立式沉箱类分离器、立式容器类分离器、卧式单根盘管式分离器、立式多管分离器等的结构和工作原理,并介绍了研发历程和相应的工程案例进展。部分侧重于进行油井产出液气一液分离用的技术方案打破了多相分离器设计的传统思维模式,为国内相关人员自主研发紧凑型多相分离技术提供了参考指导。

  10. Investigation and discussion of marine structures integrated with ocean energy devices%海工构筑物海洋能集成利用技术探讨

    Institute of Scientific and Technical Information of China (English)

    王树杰; 王举田; 刘锦昆; 袁鹏; 刘臻; 徐志刚; 季文峰

    2015-01-01

    将海工构筑物作为海洋能获能装置的安装载体可大幅降低海洋能发电的成本,同时,海工构筑物等海上设施客观上存在利用海洋能实现能量供应的需求,因此海洋能发电装置与海工构筑物相互结合具有良好的综合效益,将是未来海洋能利用的一个发展方向。针对波浪能和潮流能两种海洋能发电方式,分别对柔性叶片潮流能水轮机与进海路集成利用技术;垂直轴和水平轴潮流能水轮机以及振荡浮子式波能装置与导管架石油平台集成利用技术;OWC波能装置与沉箱防波堤集成利用技术进行了探讨,并提出海工构筑物海洋能集成利用技术中需要解决的几点问题。%Ocean energy devices installed on marine structures can greatly reduce the cost of ocean energy power generation. On the other hand, marine structures such as offshore installations need to gain power generated by ocean energy nearby. Therefore, marine structures equipped with ocean energy devices have comprehensive benefits, which will be developed in the future. According to the classification of ocean energy power generation utilizing wave and tidal current, some types of integrated utilization are investigated and discussed, such as flexible tidal current turbines integrated with perforated sea roads, vertical and horizontal tidal current turbines integrated with jacket platforms, oscillating buoys integrated with jacket platforms and OWC wave energy devices integrated with caisson breakwaters. At the same time, some questions and suggestions are put forward in order to make the utilization mature.

  11. Joint pain and Doppler-detectable bubbles in altitude (Hypobaric) decompression

    Science.gov (United States)

    Powell, Michael R.

    1993-01-01

    The observation that altitude decompression sickness (DCS) is associated with pain in the lower extremities is not new, although it is not a consistent finding. DCS in divers is generally in the upper body, an effect often attributed to non-loading of the body while immersed. In caisson workers, DCS is reported more in the lower extremities. Surprisingly, many researchers do not mention the location of DCS joint pain, apparently considering it to be random. This is not the case for the tissue ratios encountered in studying decompression associated with simulated EVA. In NASA/JSC tests, altitude DCS generally presented first in either the ankle, knee, or hip (83 percent = 73/88). There was a definite statistical relation between the maximum Spencer precordial Doppler Grade and the incidence of DCS in the extremity, although this is not meant to imply a casual relation between circulating gas bubbles and joint pain. The risk of DCS with Grade 4 was considerably higher than that of Grades 0 to 3. The DCS risk was independent of the 'tissue ratio.' There was a predominance of lower extremity DCS even when exercise was performed with the upper body. The reason for these locations we hypothesize to be attributed to the formation of tissue gas micronuclei from kinetic and tensile forces (stress-assisted nucleation) and are the result of the individuals ambulating in a 1g environment. Additionally, since these showers of Doppler bubbles can persist for hours, it is difficult to imagine that they are emanating solely from tendons and ligaments, the supposed site of joint pain. This follows from Henry's law linking the volume of joint tissue (the solvent) and the solubility coefficient of inert gas; there is volumetrically insufficient connective tissue to produce the prolonged release of gas bubbles. If gas bubbles are spawned and released from connective tissue, their volume is increased by those from muscle tissue. Therefore, the nexus between Doppler-detectable gas

  12. Deployment of a Long-Term Broadband Seafloor Observatory in Monterey Bay

    Science.gov (United States)

    McGill, P.; Neuhauser, D.; Stakes, D.; Romanowicz, B.; Ramirez, T.; Uhrhammer, R.

    2002-12-01

    MOBB (Monterey bay Ocean floor Broad Band project) is a collaborative project between the Monterey Bay Aquarium Research Institute (MBARI) and the Berkeley Seismological Laboratory (BSL). Its goal is to install and operate a permanent seafloor broadband seismic station as a first step towards extending the on-shore broadband seismic network in northern California to the seaside of the North-America/Pacific plate boundary, providing better azimuthal coverage for regional earthquake and structure studies. The successful MOBB deployment took place 40km off shore at a water depth of 1000m during three dives on April 9-11, 2002. The seismometer was buried in a 60-cm deep caisson, which was later back filled with glass beads to stabilize the instrument. New tools, including a high-pressure water-jet excavator, were developed for the ROV Ventana to accomplish these tasks. The ocean-bottom MOBB station currently comprises a three-component seismometer package, a current-meter, and a recording and battery package. Data recovery dives, during which the recording and battery package will be exchanged, are planned every three months for the next three years. A differential pressure gauge (DPG) (Cox et al., 1984) will be deployed as part of the recording package during the next data recovery dive in September 2002. The station is currently recording data autonomously. Eventually, it will be linked to the planned (and recently funded) MARS (Monterey Accelerated Research System; rl {http://www.mbari.org/mars/}) cable and provide real-time, continuous seismic data to be merged with the rest of the northern California real-time seismic system. The data are archived at the NCEDC for on-line availability, as part of the Berkeley Digital Seismic Network (BDSN). This project follows the 1997 MOISE experiment, in which a three-component broadband system was deployed for a period of three months, 40km off shore in Monterey Bay. MOISE was a cooperative program sponsored by MBARI, UC

  13. Ship operation and failure mode analysis using a maneuver simulator

    Science.gov (United States)

    Cabrerizo-Morales, Miguel Angel; Molina, Rafael; de los Santos, Francisco; Camarero, Alberto

    2013-04-01

    In a ship or floating structure operation the agents that contribute to the systems behaviour are not only those derived from fluid-structure interaction, but also the ones linked to mooring-control line set-up evolution and human interaction. Therefore, the analysis of such systems is affected by boundary conditions that change during a complete operation. Frequently, monitoring techniques in laboratory (model) and field (prototype) are based in different instrumental techniques adding difficulty to data comparison and, in some cases, inducing precision and repeatability errors. For this reason, the main aim of this study is to develop the methods and tools to achieve a deep knowledge of those floating systems and obtain capabilities to optimize their operationally thresholds. This abstract presents a methodology and an instrumental system applicable both in field and laboratory: SRECMOCOS Project (Small scale REal-time Caisson MOnitoring and COntrol System). SRECMOCOS compiles three modules. For the monitoring and control of the structure it has been developed a synchronized open and modular microcontroller-based electronic system that comprises sensors, to monitor agents and reactions, and actuators to perform pertinent actions after processing the sensors' data. A secondary objective has been to design and implement a global scaled simulator (1:22), at the 3D basin of The Harbour Research Lab at Technical University of Madrid, in which climatic agents and those derived from the rig/maneuvering setup and the structural design were included. The particular case of Campamento's drydock, in Algeciras Bay (Spain), has been used to apply and validate the methodology. SRECMOCOS Project conjugates control, monitoring and wireless communication systems in a real time basis, offering the possibility to register and simulate all the parameters involved in port operations. This approach offers a step forward into a monitoring strategy to be included in monitoring

  14. 莫桑比克马普托大桥锚碇基础方案比选%Scheme Comparison and Selection for Anchor Foundation of Maputo Bridge in Mozambique

    Institute of Scientific and Technical Information of China (English)

    周健; 邹恩杰; 李元博; 孟令亮

    2014-01-01

    The main bridge of Maputo Bridge in Mozambique is a suspension bridge with a sin‐gle span of 680 m .In order to make a rational anchor foundation scheme ,the types of caisson foundation and underground diaphragm wall were studied in accordance with the geological and hydrological condition at the bridge site and the load bearing characteristics of gravity anchor .I‐tems such as the selection of the base bearing stratum for the anchor foundation ,feasibility of the construction techniques and the applicability ,economic performance and rationality of the tech‐niques were also taken into account in the study .The results of the study indicate that the adapta‐tion of the underground diaphragm wall foundation is able to avoid the risks induced by variation of geological condition ,such as quicksand and heavy‐piping ,and is possible to strictly control the surrounding soil settlement during the construction process of anchor foundation and reduce the in‐fluence of the construction on the normal service of the surrounding railways to the maximum . When the form of the underground diaphragm wall foundation is determined ,in light of the prob‐lem of heavy‐piping ,the schemes of deep diaphragm wall and shallow diaphragm wall + curtain grouting+ waterhead lowering by deep well pumping and draining were studied .The results of the study demonstrate that by selecting the deep diaphragm wall ,the equipments required will be fe‐wer ,construction workmanship and procedure will be simplified ,the construction efficiency will be relatively higher ,and the construction duration will be shorter and controllable .As a result ,it is regarded as a rational anchor foundation scheme for Maputo Bridge .%莫桑比克马普托(M aputo )大桥主桥为单跨680 m悬索桥,为确定马普托大桥锚碇基础方案,依据大桥桥位处的地质和水文情况,以及重力式锚碇的结构受力特点,针对锚碇基础基底持力层选择、施工工艺的适

  15. Dique seco de carena. Génova

    Directory of Open Access Journals (Sweden)

    Gai, Luigi

    1965-02-01

    Full Text Available After elaborate planning, the building, towing and sinking of the ship repairing dry dock at Genoa has now been completed. The dock is 260x52x21.5 m in size. Its structure is cellular and it is made of reinforced and prestressed concrete. A special feature of this dock is that it rests on a flexible bed of sand, dredged from the sea bed. To prepare this, the following operations were carried out: mud was first dredged away, the stony outcrops were levelled off, the spaces in between the rocks were filled with concrete, then the layer of sand was placed, and finally a surface of larger aggregate was prepared on top. The method of attaching the dock to the sea bed to ensure its stability is also noteworthy. After much thought, it was decided that once the dock was sunk at its final emplacement, if its cellular compartments were filled with sand ballast, its own weight would ensure its permanent stability in the face of rough seas. The maneuvers for floating the dock, and sinking it, were also complex, since it was essential to take carefully into account the state of the weather. Any storm might have severely damaged the dock's cellular structure. The prefabrication of the caissons, the jointing of them into a large structure, the construction of enclosing walls, the provision of galleries, companionways, and housing facilities inside the dock, and the towing, sinking and ballasting of this large and heavy structure, constitute a series of building and navigational operations of great complexity, which have tested the ability of the firm Fincosit, who specialise in hydraulic projects.Después de profundos estudios se ha terminado recientemente la construcción, remolque y hundimiento del dique seco de carena del puerto de Génova, cuyas dimensiones son: 260x52x21,5 metros. Es de estructura celular, y de hormigón armado y pretensado. La particularidad de la obra estriba en el apoyo de la plataforma sobre un lecho flexible de arena dragada del mar

  16. 海上风机复合筒型基础负压沉放调平%Suction Installation and Leveling of Composite Bucket Foundation for Offshore Wind Turbines

    Institute of Scientific and Technical Information of China (English)

    练继建; 陈飞; 杨旭; 王海军

    2014-01-01

    复合筒型基础是一种巨型宽浅式负压沉箱基础,其筒内设置分舱以对托航、沉放、调平等进行控制。渗流与负压是筒型基础重要的研究内容,而目前尚未发现对复合筒型基础的相关研究。针对复合筒型基础,通过数值模型研究了其沉放调平渗流特性,以出口水力梯度为控制条件,建立了均质砂土中临界负压计算公式,并与无分舱板情况进行比较;最后分析了土质分层和渗流“反作用”对渗流场的影响。结果表明:分舱板使筒型基础沉放临界负压降低约10%,调平临界负压随倾角迅速下降;分层土体中相对渗径变长,临界负压增大,不容易发生渗透破坏;渗流使筒内土体疏松,渗透系数变大,造成内侧土体中水力梯度减小,对土体渗透稳定起到保护作用。%Composite bucket foundation is a kind of large-scale shallow suction caisson,which contains inside bulk-heads to control towing,installation and leveling. The researches on seepage and suction are important for installation,but currently there is no correlative study on composite bucket foundation. This paper presents a numeri-cal analysis of the seepage characteristics of large-scale bucket foundation in both homogeneous and layered soil pro-file. The formula for critical suction is proposed,with the exit hydraulic gradient as control condition. Then a com-parison is presented between the critical suction of bucket foundation with and without bulkheads. The results show that the critical suction is reduced by 10% by the bulkheads. Additionally,the analysis of seepage in the suction level-ing shows that the critical suction drops rapidly with the increase of dip angle. In the layered soil,the normalized seepage path increases and the critical suction value grows. The seepage flow loosens the inner sand and increases the permeability coefficient,which is favorable to the seepage stability of soil.

  17. Engineering for Operation of a Future Belgian Deep Geological Repository for ILW and HLW - 12379

    Energy Technology Data Exchange (ETDEWEB)

    Haverkamp, B.; Biurrun, E.; Nieder-Westermann, G.H. [DBE TECHNOLOGY GmbH, Peine (Germany); Van Humbeeck, H. [ONDRAF/NIRAS, Brussels (Belgium); Van Cotthem, Alain [Tractebel Engineering SA, Brussels (Belgium)

    2012-07-01

    In Belgium, an advanced conceptual design is being elaborated for deep geologic disposal of high level waste (HLW) and for low and intermediate level waste (LILW) not amenable for surface disposal. The concept is based on a shielded steel and concrete container for disposal of HLW, i.e., the Super-container. LILW will be disposed of in separately designed concrete caissons. The reference host rock is the Boom Clay, a poorly indurated clay formation in northeastern Belgium. Investigations into the potential host rock are conducted at the HADES underground research laboratory in Mol, Belgium. In 2009 the Belgian Agency for Management of Radioactive Waste and Enriched Fissile Materials (ONDRAF/NIRAS) initiated a four year research project aimed at confirming the fundamental feasibility of building and operating a repository. The goal of the program is to demonstrate at a detailed conceptual level that the proposed geologic disposal system can be safely constructed, operated, and progressively closed. Part of the broader research efforts being conducted includes evaluations optimization of the waste transportation shaft, subsurface transportation system, ventilation system, and evaluation of backfilling and sealing concepts for the repository design. The potential for implementation of a waste retrieval strategy encompassing the first 100 years after emplacement is also considered. In the framework of a four year research program aimed at confirming the fundamental feasibility of building and operating a repository in poorly indurated clay design studies have been underway to optimize the waste transportation shaft, subsurface transportation system, and ventilation system. Additionally backfilling and sealing concepts proposed for the potential repository have been reviewed in conjunction with impacts related to the potential future inclusion of a retrievability requirement in governing regulations. The main engineering challenges in the Belgian repository concept are

  18. The use and evolution of the CEA research reactors; Utilisation et evolution des reacteurs de recherche du C.E.A

    Energy Technology Data Exchange (ETDEWEB)

    Rossillon, F.; Chauvez, C. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1964-07-01

    combustibles refractaires et de graphites speciaux, et l'etude du comportement des liquides organiques sous radiations. Les installations de MELUSINE sont actuellement en cours de modernisation. La Pile SILOE, egalement du type piscine, est en fonctionnement a 15 MW depuis la fin de l'annee 1963. Les performances realisees constituent un progres considerable dans le domaine des piles piscines, les flux obtenus etant d'un ordre de grandeur qui exigeait jusqu'a present l'adoption d'une structure 'a caisson' dont on connait les nombreux inconvenients pour la realisation des experiences. La pile SILOE sera surtout utilisee pour l'etude des materiaux de structure, du graphite, des combustibles refractaires, et pour la physique du solide. La Pile PEGASE, en service au Centre de Cadarache depuis 1963, est destinee uniquement au test, en vraie grandeur, des elements combustibles des filieres EDF et EL4. Le programme actuel pour les 8 boucles de la Pile concerne les elements des Piles EDF 2, EDF 3 et EL 4. De nouvelles boucles sont en cours d'etude pour les elements combustibles des piles EDF 4 et EDF 5. L'orientation des programmes du CEA a mis en evidence d'importants besoins d'irradiations en neutrons rapides. La Pile OSIRIS, actuellement en cours de realisation, permettra de completer les moyens du CEA dans ce domaine, tout en venant compenser, pour le Centre de Saclay, l'arret prochain de EL 2. OSIRIS est une pile a eau legere, mais dont la structure assez particuliere permettra un fonctionnement a 50 MW sans les inconvenients habituels lies a l'existence d'un caisson lourd et etanche. Cette pile, dont la mise en service est prevue pour 1966, sera surtout utilisee pour l'etude des materiaux de structure, du graphite et des combustibles refractaires; elle permettra egalement d'accroitre la production des radioisotopes a haute activite specifique, et de developper les techniques d