Advanced Materials Research Vols. 163-167

Abstract: Wave-passage effect of the seismic is the main reason of multi-support excitations, and there are always two analysis methods which are large mass method and acceleration method to study on the multi-support excitations, this paper take one kind of trussed structure as an example, use the two methods to consider the wave-passage effect of seismic, compare the difference between the results from using the two methods, and also compare the difference between single-support and multi-support excitations. This paper draw a conclusion that it is a precise way to using ABAQUS to analysis the wave-passage effect of the seismic; wave-passage effect of the seismic has an great influence on the reaction of long-span spatial structures, it must be considered in the similar projects; and the large method and acceleration method both have their advantages and disadvantages, so we should give concrete analysis to concrete problems.

Abstract: Cable-stayed bridge with single cable plane has advantages in wide field of view. However, the problem of stability becomes especially important, because it can’t provide torsional stiffness. Based on LanQi SongHua River Bridge, a concrete cable-stayed bridge with single cable plane, the dynamic character, wind-resistant stability and flutter instability are analyzed, especially the analysis of the flutter stability at maximum double cantilever stage during construction phase. The paper analyzes the dynamic characters of the finite element model of the whole bridge through response spectrum method to reap the natural frequency, the vibration modes and other parameters, then checking the flutter stability. The results show that the bridge is very safe either at maximum double cantilever stage or finished stage. The analysis method provides a basis and references for the wind-resistant of cable-stayed bridge with single cable plane.

Abstract: Park-Ang seismic damage model is increasingly concerned due to it considers not only maximum elasto-plastic deformation, but also low cycle fatigue accumulated hysteretic energy, while research on the method of seismic performance evaluation based on the model is still rare. Therefore, a new evaluation method on the basis of damage spectra is proposed in this paper. Damage spectra of site I considering three kinds of ultimate deformation ductility factor are built firstly, and then transformation relationship between damage of MDOF and SDOF of frame structures is researched. Lastly, procedure of seismic damage evaluation on the structure is proposed. An example is used to confirm the validity of the spectra-based seismic performance evaluation method. The example analysis shows that: the method proposed here is reasonable to consider the impact of the cumulative hysteretic energy on the structural damage. The results from the method have good consistency with the time history analysis results. It can assess the extent of structural damage from the statistical viewpoint.

Abstract: Incremental dynamic analysis (IDA) is an effective method for evaluation of seismic performance of building structures. Based on the principle and characteristics of IDA method, evaluation steps of investigating deformation and ductility of steel reinforced concrete (SRC) structures under increasing earthquake loading are put forward. Limit states of different performance levels for structures are connected with IDA curve slope whose decrease amplitude is determined according to current test data. Based on the proposed constitutive model of steel and concrete, a regular steel reinforced concrete frame structure is analyzed with IDA method, and distribution of story drift angle and ductility for four performance levels are investigated. The calculation results show that the SRC frame has better seismic performance when subjected to random earthquake waves.

Abstract: In this paper, to verify the effectiveness and reliability of nonlinear numerical simulation based fiber model, two computer programs (CANNY 99 and IDARC-2D), in which shear wall elements were respectively simplified by fiber model and equivalent beam model, were adopted to perform the numerical simulations of 10 times shaking table tests of a nine story 1:6 scale frame-shear wall building model in this paper. Analysis model including beam, column and wall element in CANNY 99 is elaborated in detail. Test results are compared with simulation results in some aspects such as natural frequency, time history responses, and peak value responses. Results demonstrate that fiber model and Equivalent beam model can simulate the elastic-plastic earthquake response of R.C. wall structures very well.

Abstract: A theoretical analyzing approach about a novel seismic isolation system, DFPS (Double Slipping-Surfaced Friction Plate System), is presented in this paper. Its governing equation is similar to that of the FPS friction pendulum system with single slipping surface. It is shown that the inter-storey drift resulted from seismic action could be drastically decreased on buildings equipped with DFPS system. If an optimum combination of slide radius and slipping friction coefficient is adopted, the seismic isolation effectiveness could be as high as 90%.

Abstract: An overall numerical model for a reinforced concrete frame was established and in parallel, a group of simplified models were established for the same structure according to the particular characteristics of the subjected load such as impact load, dynamic load and quasi-static load, to investigate their dynamic behaviors. Results show that it is reasonable to introduce the simplified models for reinforced concrete frame in analysis work.

Abstract: The correlation between intensity measures (IM) for pulse-like ground motions and nonlinear deformation demand of single-degree-freedom-systems (SDOF) is researched, and the efficiency of IM is described. Based on dynamic time analysis of SDOF systems subjected to 72 pulse-like ground motions, the present study investigates the variation of the correlation coefficient between IM for pulse-like ground motions and maximum nonlinear deformation demand of SDOF with the constant-ductility or constant strength system setting. Linear regression analyses are performed on these results to identify the efficiency of peak ground velocity (PGV) and spectral acceleration Sa(T1), which is used as IM for pulse-like ground motion. The study shows that IM of pulse-like ground motions depend distinctly on the system period, ductility levels and strength reduction factors have important influence on the correlation and dispersion, and Sa(T1) and PGV are relatively the good IM for pulse-like ground motion.

Abstract: Based on the theory of maximum likelihood estimation, a set of nonlinear equations is first derived for determination of parameters of Weibull distribution. To speed up convergence, an efficient algorithm is proposed for solving the parameters. Further, a large-span roof structure is taken to demonstrate the proposed method. It is proved that the responses of a nonlinear structure have non-Gaussian properties under the excitation of non-Gaussian stochastic wind pressure field. By Weibull distribution fitting, the maximum and minimum values of structural response with a certain assurance rate are computed, and the results are compared with those obtained from normal distribution.

Abstract: To reveal the stress-strain properties of Gangou high rockfill embankment with 71m high under seismic loads and provide the reference for its security evaluation and the seismic reinforcement design. By simplifying the high rockfill embankment as the plane problem, establishing two-dimensional finite element model, inputting EL Centro and applying seismic response spectrum method, the dynamic response of high rockfill embankment under seismic loads were simulated. The results show that: With the increase of embankment height, the dynamic response presents increasing tendency; The maximum displacement occurs on the right side of the embankment top, t1474he maximum acceleration appears at the middle of embankment slope. From the view of seismic design, the right side of the embankment top and the middle of embankment slope are the focus of seismic design.