Four types of seismic design details were tested using 11 transfer column specimens and one comparison specimen of RC under low cyclic reversed loading. Test results show that diagonal cracks control the failure pattern and damage occurs mainly in the RC section with weak shear capacity in the transfer columns. There is a large difference in the bearing capacity and ductility of the transfer columns according to the test results, which indicates that the strengthening effect of diverse structural measures is quite different. The section ratio of I-section-encased steel and the axial compression ratio also have a great influence on the bearing capacity and ductility. Although the bearing capacity of transfer columns with additional longitudinal bars and additional X bars is relatively large, they have poor deformation capacity. Setting more stirrups along the columns is the best structural measure to enhance the seismic performance. The studs on the I-sectionencased steel by welding can help to complete the stress transfer between the steel and concrete, and avoid performance degradation of the two materials due to bonding failure. 相似文献
Evaluation of structural performance under seismic excitations from low intensity to high intensity is essential to verify the seismic resistant capacity of a structure, and usually carried out by the incremental dynamic analysis (IDA) method or pushover method. The recently developed endurance time (ET) method is another method that uses dynamic pushover excitations, i.e., endurance time acceleration function, to obtain results similar to those obtained by IDA or pushover methods with low computational cost and acceptable accuracy. This study proposes an improvement on the ET method by considering more restrictions for both the elastic and inelastic response spectra in the generation procedure, and by specifying a target duration. Four reinforced concrete frame structures with 4, 8, 12, and 16 stories are adopted to verify the accuracy of the improved method. Comparison of the results obtained by the proposed method, the ET method and the IDA method shows that the improved method has a higher accuracy than the ET method. For evaluation of structural responses under specific ground motion intensity, which is typically required in seismic design codes, the results obtained by the proposed method are compared with five commonly used ground motion selection methods, and shows the proposed method provides acceptable accuracy for engineering applications.
Science China Earth Sciences - The Xiamaling Formation of 1.4–1.35 Ga in Jixian Section and adjoining areas represents a unique Ectasian Period (Mesoproterozoic) sedimentary sequence in the... 相似文献
The development of a powerful numerical model to simulate the fracture behavior of concrete material has long been one of the dominant research areas in earthquake engineering.A reliable model should be able to adequately represent the discontinuous characteristics of cracks and simulate various failure behaviors under complicated loading conditions.In this paper,a numerical formulation,which incorporates a sophisticated rigid-plastic interface constitutive model coupling cohesion softening,contact,friction and shear dilatation into the XFEM,is proposed to describe various crack behaviors of concrete material.An effective numerical integration scheme for accurately assembling the contribution to the weak form on both sides of the discontinuity is introduced.The effectiveness of the proposed method has been assessed by simulating several well-known experimental tests.It is concluded that the numerical method can successfully capture the crack paths and accurately predict the fracture behavior of concrete structures.The influence of mode-Ⅱ parameters on the mixed-mode fracture behavior is further investigated to better determine these parameters. 相似文献
