Comparative Analysis Of Stiffness Control Schemes For Building Structures Supported By Foundations At Different Ground Levels

As with mountainous building structure increasingly rapid development, it’s more and more widely applied in a lot of mountainous cities, the most common form being cliff-structure. Because of the vertical irregularity leading to stiffness mutation, the stress and deformation characteristics of the cliff-structures are quite different from that of ordinary structures. And now the study on how to control the vertical uneven stiffness of the cliff-structure is still shortage. Therefore, this article embarks from the stiffness controlling in order to find an optimal scheme of the stress of the structure performance showing in good condition. Mainly two kinds of stiffness controlling scheme was carried out on elastic and elastic-plastic analysis of cliff-structure to evaluate the structure’s seismic performance and discuss the effectiveness of stiffness controlling scheme.This paper takes the cliff-structure as the research object. Using the finite element analysis software SAP2000 goes on elastic stage analysis of the cliff-structure by controlling different stiffness distribution equivalent stiffness ratio and corresponding parts stiffness ratio. With the software PERFORM-3D dynamic elastic-plastic of the cliff-structure is analyzed under severe earthquake in different stiffness controlling scheme,Through the analysis of the cliff-structure in this paper, the main conclusions are achieved as follows:①When different stiffness distribution control cliff-structure, the computing stiffness at the bottom of the structure cannot be simply to use D value method. D value method is amended using series-parallel column, then the column’s lateral stiffness of single range across the underlying framework is amended.②Using equivalent stiffness ratio in the technical specification for concrete structures of high-rise building control the stiffness of the cliff-structure. Due to the drop at the bottom of the layer structure existing two different embedded fixed end, calculated height of the ground plane in the following sections depends on the stress of the earthing rod and the ground pole on the ground plane. At last, calculated height of the bottom structure starts from on the ground plane.③ As elastic phase analysis, equivalent stiffness ratio shows good control effectiveness in story drifts and shear-weight ratio under two kinds of stiffness controlling scheme. Elastic-plastic analysis of the structures was carried out through the two stiffness control scheme. It can be find controlling different stiffness distribution can show good control effectiveness under the rare earthquake or devastating earthquake by comparing to story drifts, plastic hinge, hysteresis curve, etc.④Though the contrast of the elastic and elastic-plastic analysis, it is suggested that controlling different stiffness distribution controls seismic performance of the cliff-structure design. Equivalent stiffness ratio may still be shortcomings on structural rigidity control and need to be researched.⑤ The corresponding parts stiffness ratio is put forward for the first time, which may be shortcomings on seismic performance and need to be further studied.