Numerical Simulation Research On Mechanical Properties Of Reinforced Concrete Shaft Tower With Transfer Structure

Shaft Tower is a kind of important industrial buildings,plays an important role in the construction and production of mine process, it is an important guarantee of the whole mine personnel and material transportation. Now,a lot of vertical shaft construction using a freeze method, frozen pipe make the pile foundation of frame column difficult to meet the design depth, increasing the construction cost and the difficulty, so produced the shaft with conversion structure. At present,the research and application for such new type shaft tower is very few,so it is necessary to take well study on this new type shaft tower.In this paper, based on a real shaft tower project as the background, using finite element software SAP2000 build 3D model of the shaft tower, by modal analysis, response spectrum analysis, time history analysis and Push-over analysis, the paper analyzed seismic performance of the shaft tower under the action of the rare earthquake and often encountered earthquake, determine the weak parts of structure. Then, by changing transfer beam stiffness and the stiffness between the transfer layer up and down and floor calculation assumption, analyzed the influence of the change of these parameters effect on the seismic performance.Through the analysis found,the weak parts of Shaft Tower with transfer structure in the fifth floor of the tower, under the rare earthquake action, the edge of fifth floor beam breakage occurs first, then, the bottom of second inside frame column has plastic hinges, so the bottom of second inside frame column should be properly strengthened in the design of shaft tower. With the increase of the transfer beam stiffness, the seismic performance of shaft tower upgraded, but the effect is not large, the shear forces and bending moments of the buttress walls also increased, which means an adverse influence. In short, through the increase the transfer beam stiffness in practical engineering to improve the overall seismic performance is not economic, so meet the requirements at the same time reduce the transfer beam stiffness is reasonable. With the stiffness between the transfer layer up and down decreases, lateral stiffness of shaft towers were increased in the whole two horizontal directions, the floor displacement and interlayer displacement angle is also reduced, the internal force of the transfer beam and the buttress walls are reduced a lot, but the ratio of this decreased is diminishing. So when meeting the economic situation, increasing the thickness of the bottom shear wall are beneficial for seismic performance of the shaft tower and can make internal force of transfer beam decreases under the action of earthquake. Different floor calculation assumption have obvious affection to seismic action effect of structure, the floor assumption of transfer beam is the main factors influencing the seismic effect of transfer beam, the other layers floor assumption has little influence. When use rigid board assumes, the shear of inside frame column and interlayer displacement angle of shaft tower were small, if shaft tower using rigid board assumes to calculate structures seismic deformation and internal forces and the results meet the specification requirements, but using elastic board assumes may be not. Therefore, for complex and special structure, structure seismic check should use elastic board assumption.Through the research in this article,can provide a reference for the design and Seismic Performance analysis of similar shaft structure.