ویژگیهای لرزه ای مدل جدید ساختار فضایی دیوار برشی
Abstract
1- Introduction
2- Test background
3- Experimental test results
4- Conclusions
References
Abstract
Effective seismic properties are a basic requirement in precast shear wall applications. Therefore, this study focuses on the evaluation and improvement of precast shear wall seismic properties using the new pore-forming grouted connector with welded closure confinement steels (NPGCS) developed in previous research. The NPGCS connector reliability was verified and the seismic properties of the NPGCS spatial structure model were evaluated by carrying out a low cyclic reversed lateral loads experimental test on the NPGCS precast shear wall spatial structure model containing superposed connecting beams and precast shear walls, which were selected from a practical high-rise precast residential building. According to the testing results of the crack distribution and component failure modes, the superposed connecting beam properties were weak, and damaged early in the shear failure mode, while the precast shear walls cracked after the steel bars in the superposed connecting beams yielded. Furthermore, the failure mode indicated that the NPGCS connection applied in this spatial model is reliable, while two new weak sections were proven to exist at the connector ends. Together with the precast joint interface slip, the dowel shear action is demonstrated to be harmful to the joint interface properties. Additional seismic parameters, namely capacity, ductility, stiffness and energy consumption, were used to complete the evaluation of the seismic properties of the NPGCS spatial structure model. Overall, although the NPGCS spatial model ductility is low, the strengths are high, leading to continued effective energy consumption properties, which indicates favourable seismic properties of the NPGCS spatial structural model.
Introduction
Precast technologies have made substantial advances in industrial production, environmental protection and high mechanical reliability, among others. However, precast technologies are still limited in terms of extensive application in China, for the two following reasons: (1) as most Chinese territories are in seismic areas, stricter seismic design requirements exist; and (2) owing to the high population density in south-eastern China, most Chinese residential buildings are high-rise shear wall structures with 20 to 33 floors, which drastically enlarge the seismic loads [1]. In recent years, numerous new types of steel bar connectors [4–12] and testing technologies [13–16] have been developed based on grouted connectors [2] and inherited from the Precast Seismic Structural System (PRESSS) programme connectors [3]. Figs. 1 and 2 depict two typical grouted connectors that are widely used in China. Although these new grouted precast connectors are capable of providing very high connector performance, special manufacturing technologies are required, such as stressing in unbounded pre-stressed connectors [17] and steel sleeves in grouted connectors. All of these special manufacturing technologies will increase the cost and dramatically limit the application of precast technologies.