Abstract: Rockfall is a frequent engineering disaster confronted in the capital construction engineering. The key for preventing rock fall is the evaluation of the rockfall trajectory. After extensive analysis, an innovative calculation method of rockfall trajectory, called segmented cycling algorithm, has been proposed in the paper. According to the contact relationship between the rolling stones and the slope surface, the movement divided into three sections which include the jumping phase, the rolling (sliding) phase and collision phase, the formulae to calculate the velocity of different phases of motion are proposed respectively by segmented cycling algorithm. A similar model, based on a rock slope in Chongqing-Wanzhou highway, is established to verify the capability and validity of the presented algorithm. Compared with existing algorithm, the new algorithm is simple and clear, easy to use and so on. The algorithm meets the law of the movement of rockfall and can be used to forecast the kinetic feature of rockfall. It is also used as the basis for rockfall disaster prevention.
Abstract: This paper investigates modeling approaches of circular concrete-filled steel tube (CFT) column under cyclic load based on flexibility and fiber model. The effects of model parameters on modeling results is discussed, including constitutive relationship of materials, division of the fiber section, and the number of integration points. The results show that the material constitutive relationships of concrete and steel are prime important to the accuracy of the computational results. Three to five integration points for one CFT column in the flexibility-based analysis can achieve the desired accuracy and computational efficiency. The computational result is not sensitive to the number of sectional fibers. However, the desired accuracy can not be obtained if the number of the sectional fiber is not enough.
Abstract: The research of structural vulnerability analysis is mostly based on the Cornell theory. Using other methods to do seismic fragility analysis is relatively rare. In this paper, beta probability density function is used to continuously fit the probability distribution of damage levels for a frame structure under given seismic intensities. It gets the probability density distribution of the structure under different intensities. The results show that, based on beta probability density function, it can get comparatively accurate solution for structural seismic vulnerability analysis. This method is not only simple and fast, but also the damage state is expressed by continuous damage parameter. The research provides the reference for future earthquake damage prediction and the elaborate calculation about economic loss of earthquake insurance.
Abstract: Based on analysis of five different conditions’ full scale model tests of the fastener tubular steel scaffolding, the paper introduces that notional lateral loads can imitate the effect which generalized imperfections of the falsework(initial imperfections, node semi-rigid and so on) give the bracket’s stability capacity. According to the finite element software ANSYS, the falseworks’ stability capacities of different conditions have been imitated and analysed, Analysis results compare with test results. The final result indicates that it is reasonable that notional lateral loads in certain scope can imitate generalized initial imperfection. Research results can be used for on-site t technical personnels’ design and safety control.
Abstract: This paper is concerned with the study on internal forces of structure by building model in ANSYS under unidirectional seismic wave, bi-directional seismic waves and two-way and reverse seismic wave. The results revealed that the moment effect of frame structure under bi-directional seismic waves and two-way and reverse seismic wave is bigger around 30% than it under unidirectional seismic wave. And the torque accretion multiple of irregular structure is bigger around 1 than the corresponding regular structure. Therefore, we should take into account the effect of multi-dimensional seismic and the torsional effect of the irregular structure in structure design.
Abstract: In the process of evaluating the stability of some rock slopes, the discontinuities which mainly destroy the stability of future slope can not be understood and the locations of the slope can not be determined because of lacking of the exploration data. This paper determines the combination molds and the location of potential sliding surfaces using the method of crack network simulation to do statistics about all the discontinuities, which aims to resolving the problems of determining the locations and idiographic conformations of potential sliding surfaces in the rock slope.
Abstract: Following with the Wenchuan Earthquake of 2008 in China, the Haiti Earthquake of 2010 and so forth, a series of geologic hazards occur all around the world, and they are becoming more disastrous. Measures should be taken to prevent and reduce the disasters; however, providing accommodation for the refugees is an emergent issue after earthquake as well. Compared with the traditional temporary dwellings, the newly designed ones, whose properties, as contingent, portable, functional, humanized and periodical, can meet all needs in the new environment. The authors conduct a careful research on the design of this temporary dwelling, and later strengthen and develop its portable advantage in order to provide new choice for the accommodation for the refugees and other applications in future.
Abstract: As a part of the collaborative studies between China, Australia and the UK, examing sulfate attack on concrete, this paper reports the experimental results obtained from the Chinese laboratory. Specimens were immersed in sodium and magnesium sulfate solutions with concentrations of 500mg/L, 5000mg/L and 50000mg/L. Investigations were conducted over approximately a one year period. Susceptibility to sulfate attack was assessed in terms of changes in the mass and length of specimens, the compressive strength of the concrete, as well as the diffusion depth of sulfate-ions into the concrete at fixed intervals. Several differences were observed between these results and those reported in studies from the UK laboratory.
Abstract: In this paper, a formulation for calculating ultimate bending capacity was created. A nonlinear finite element model was established using ANSYS with right material parameters for prestressed concrete box girder with steel plate and concrete composite strengthening (SPCCS).A comparison was made between analysis results and function formula data, and results show that the numerical result s of nonlinear static analysis are in good agreement with the formula results. Effect of SPCCS and steel plate strengthening was compared, and the results show that SPCCS does more effective.
Abstract: In the present of paper, four experimental steel tubular columns with partial filled-concrete under reversed cyclic lateral load and constant axial load were numerically analyzed by finite element package ABAQUS. Under certain conditions of the radius-to-thickness ratio Rt and the slenderness ratio λ parameters, effect of filled-concrete height on ultimate strength and ductility of this type bridge pier was investigated. These numerical results of tubular columns with partial filled-concrete were compared with the previous experimental results. It was found that these numerical results agree with the experimental ones very well. And these load-displacement hysteretic curves, which were obtained from numerical model, indicated that filled-concrete height had greatly affected the ultimate strength and ductility of steel tubular bridge pier with partial filled-concrete.