Generally, the active structural control system belongs to the discrete time control system, and the sampling period is one of the most important factors that would directly affect the performance of tbe control system. In this paper, active control approaches by using the discrete-time variable structure control theory are studied for reducing the dynamic responses of seismically excited building structures. Based on the discrete reaching law method, a feedback controller which includes the sampling period is presented The controller is extended by introducing the saturated control method to avoid the adverse effect when the actuators are saturated due to unexpected extreme earthquakes. The simulation results are obtained for a single-degree-of-freedom (SDOF) system and a MDOF shear building equipped with active brace system (ABS) under seismic excitations. It is found that the discrete variable structure control approach and its saturated control method presented in this paper arc qu0e effective.

A new seismic energy dissipation shear wall structure is proposed in Ibis paper. Tile new shear wall is one with purposely built-in vertical slits within the wall panel, and rubber belts as seismic energy dissipation devices are installed in the vertical slits. In order to verify this concept, shaking table tests of a 1O-storey shear wall modcl with rubber belts filled in the vertical sifts were carried out, and comparison of seisndc behaviour was made between the new shear wa]l system and a shear wall with reinforced concrete connecting beams as energy dissipation, Furthermore, the seismic behaviour of this new shear wall is analysed by a finite element time history analysis method The test and analysis show thai the new shear wall system has a very good ability to dissipate seismic energy and is easy to use in engineering practice.

A three-dimensional finite element analysis of the soil-pile-structure interation system is presented in this paper. The analysis is based on data from shaking table model tests made in the StaTE Key Laboratory for Disaster Re-duction in Civil Engineering. Tongji Universtiyt. China. The general finite element program ANSYS is used in the anal-ysis. The surface-to-surface contact element is taken into consideration for the nonlinearity state of the soil-pile interface. and an equivalent linear model is used for soil behavior. Acomparison of the results of the finite element analysis with the data from the shaking table tests is used to validate the computational model. Furthermore, the reli-analysis with the data from the shaking table tests is used to validate the computational model. Furthermore, the reli-ability of the test result is also verified by the simulation analysis. It shows that speration, closing, and sliding exist between the pile foundation and the soil. The distribution of the amplitude of strains in the pile, the amplitude of con-tact pressure, and the ampliude of sliding at the soil-pile interface are also discussed in detail in this paper.

A combined energy dissipation system is developed in this paper. In this system lead robber dampers and their parallel connection with oil dampers are used in the braces of a structural frame. A dynanric analysis method of the system, including the modelling of the lead robber damper and the oil damper, is proposed. In the analysis method, the restoring force characteresfics of the lead rubber damper is simulated by the Boue-Wcn hysteretic model, and the behaviour of the oil damper is simulated by a velocity and displacement-related model in which the contributions of the oil damper to the damping force and stiffness of the system are considered. A series of shaking table tests of a three storey steel frame with the combined energy dissipation system are carried out Io evaluate the performance of the system and Io verify the analysis method. The test and analysis show that the performance of the combined energy dissipation system is quite satisfactory and there is a good agreement between the analysis and test results, which indicates that the analysis method proposed in this paper is valid and suoable for the dynamic analysis of the combined energy dissipation system.

Coupled shear wall is one of the main structural elements in high-rise buildings. In this paper, a nonlinear macromodel is proposed to simulate the behavior of coupled shear walls. This model is composed of a multivertical-element model for wall piers and a combined model for coupling beams. In the model for wall piers, some key characters, such as shifting of neutral axis within the wall section, interaction among flexure, shear, and axial forces, can be taken into account. In the model for coupling beams, the deformation of flexure and shear, and the interface bond–slip action are considered by using different elements. Experiments of coupled shear wall specimens with different sizes of coupling beams are carried out to verify the proposed model. A comparison of the analysis with the test results shows that the model is an efficient one in nonlinear analysis of coupled shear walls.