Applied Mechanics and Materials Vols. 580-583

Abstract: This paper focuses on the mechanical properties of galvanized iron wire under various conditions of earthquake-type strain rate. The dynamic tensile test of galvanized iron wire was conducted on MTS New 810 electro-hydraulic servo-controlled testing system. The dynamic tensile constitutive relationship of galvanized iron wire was proposed under seismic strain rate. The accuracy of the proposed constitutive relationship of galvanized iron wire was verified by comparing with reinforcing steel.

Abstract: Many studies have demonstrated that the story drift is the critical parameter that is best correlated with damage in buildings. In this study, an approximate solution for mean value and standard deviation of peak story drift at each story of a building structure under earthquake motions was derived, based on random vibration theory. The accuracy was demonstrated by the Monte Carlo simulation solutions. Comparison of the computed results with the available simulation results indicates that the proposed solution is satisfactory. The results of numerical examples show that the period of a building structure plays a major role that affects the peak drift at each story. The peak drift at each story increases as the period of the structure increases.

Abstract: In order to meet the requirements for using function of structure, openings are often needed to be laid out in shear wall, and the mechanical behaviors of the wall will be significantly influenced. The experimental analysis, establishment of simplified mechanical model and numerical simulation researches on shear wall with opening were reviewed, the research findings on shear wall with opening at home and abroad were summarized, and the seismic behaviors were induced and analyzed. The problems about seismic behaviors of shear wall with opening which need to be solved urgently were pointed out.

Abstract: In current seismic design procedure, structure base shear is calculated according to the linear elastic response spectra divided by the response modification factor, which accounts for ductility and overstrength of a structural system. In this paper, the response modification factors of Y-eccentric braced steel frames (YECBF) designed based on Chinese Code were evaluated by an improved pushover analysis on 12 examples with various stories and spans lengths. According to the analysis results, the effects of fundamental periods, storey numbers, and spans of frames on the behavior factor were studied. In the end, an appropriate response modification factor was proposed for YECBF designed base on Chinese Code.

Abstract: Using the three-strut model, five types of frame structures, i.e., without infilled walls, with full infilled walls, without bottom-storey infilled walls, without middle-storey infilled walls and without top-storey infilled walls, were studied. The mode analysis and nonlinear time-history analysis were carried out on each model. In order to investigate the effects of infilled walls with different configurations on the seismic behavior of reinforced concrete frame structures, the structural periods, the ratio of T_t to T₁ and the maximum interstorey drifts were analyzed. The results indicate that the infilled walls enhance the lateral stiffness of frames, and the configuration of infilled walls has little influence on the calculation of structural periods. It also shows that the weaker storey is formed due to the unreasonable layout of infilled walls, thus leading to the collapse of the whole structures under the seismic action.

Abstract: Bottom-business multi-story masonry structure is widely used in small and middle towns in the southward in China. In the downtown of Beichuan county which affected by Wenchuan earthquake, more than 80% of this kind of building collapsed. But the Apartment of Beichuan Telecommunication Bureau behaved well earthquake resistant capacity with a moderate damage in the earthquake. The obvious difference between this building and others is the setting of winged columns in the front longitudinal wall of the first floor. For proving the influence of these members in the structure seismic capacity, the earthquake simulation shaking table test of 2 1/5 reduced scale models were designed and carried out. The models dynamic response, acceleration, displacement and strain were measured and collected, that model with winged columns behave well was testified. And the reinforcement method of balancing stiffness and increasing ductility is put forward. The results provide a foundation for the retrofitting design of the existing houses.

Abstract: A 1/5 scaled three-story RC (reinforced concrete) frame-wall model was modeled in microconcrete and fine wire and carried out on the shaking table. The main objective of this paper aimed to investigate the dynamic characteristics, the seismic responses, and the failure mechanisms of the model, also concentrated on the strain rate of concrete on structural members under seismic action. Based on the test results, some significant conclusions are obtained for engineering practice.

Abstract: In order to research the self-centering capacity of prefabricated frame joints, this paper designed analysis models of prefabricated frame joint with the finite element software ABAQUS, contrastively analyzed seismic behavior of joint applied pretention and joint without pretention. Joint applied pretention is found to have better self-centering capacity. Then the paper calculated and analyzed the factors of stretching control stress, number of post-tensioned steel. The results show that number of post-tensioned steel has a greater influence on the seismic behavior of the structure, and the stretching control stress has influence in a certain range. The results have some degree of guiding significance for the popularization of prefabricated frame.

Abstract: To study the effect of damping on seismic performance of steel frame, using the pseudo dynamic test by inputting damping and no damping to analyze the seismic performance of semi-rigid steel frame. Analysis was focused on the effect of damping on the panel zone strain, story drift and interlayer force.The conclusion was that under the more severe earthquake, the structural damping had effects on the seismic performance of semi-rigid steel frame.

Abstract: Dynamic structural model of saturated soil was introduced, and combining with the finite element program, the finite-infinite element models of end bearing pile foundations was established. Four models of interface between pile and soil including absolutely jointed, slippage, crack, both slippage and crack were considered to study the interface’s effect on pile foundation’s dynamic characteristics. The results were as follows: the interface’s mechanical behavior has a little influence on the distributions of pile section’s shearing stress and horizontal displacement. Pile section’s shearing stress reaches the maximum near the ground surface when interface is slippage or crack, and reaches the minimum ones when interface is absolutely jointed. Horizontal displacement could be divided into two phases and the ground surface is the dividing line. The interface’s behavior greatly changes the distribution of acceleration time-history curve. To different models, the maximum acceleration all appears at the ground surface. On the whole, the interface’s behavior has significant influence on end bearing pile, which should be pay attention in the design from now on.