An Analysis Of The Seismic Destruction In The Frame Structures With Strong Beam And Weak Column In Wenchuan Earthquake In Sichuan

The deformability of frame structures is closely related to the destruction mechanism of the frame. In Wenchuan Earthquake in Sichuan Province on May 12th, 2008, the destruction of the columns of numerous frame structures is in the form of a serious plastic hinge, instead, that of the beams is lesser, which is typical of“strong Beam and Weak Column”and therefore fail to meet the requirements of aseismatic design with“strong column and weak beam”. Causes behind it can be multiple, which mainly includes: the inconsiderateness of the strengthening effect of the cast-in-situ floor slabs towards the frame beams, the unfavorable layout of the in-filled walls and the over-reinforcement of the structure design. This paper, built on the above-mentioned situation, is intended to further uncover the causes behind these three main ones. And to achieve this goal, a lot of researches has been done, they are:(1) the seismic destruction in the frame structures in Wenchuan Earthquake has been generalized and the significance of promulgating relevant national regulations for standardizing‘strong column and weak beam’inelastic development mechanism;(2) the relevant theoretical basis for the elastic-plastic analysis of the frame structures has been generalized;(3) with the aid of the non-linear finite element program MSC.MARC, a simulation analysis of typically seismic damaged houses in Wenchuan Earthquake (to simulate the reinforcement of the cast-in-situ floors slabs towards frame beams in their bearing capacity and rigidness) has been done for analyzing what degree is the cast-in-situ floors slabs related to the seismic damage caused by“strong beams and weak columns”;(4) an in-filled walls model has been set up and the influence of the in-filled walls upon the seismic damage caused by“strong column and weak beam”has been analyzed; the influencing way of in-filled walls has been analyzed by observing the ruined conditions of destruction mechanism and plastic hinge;(5) the relations between the phenomenon of“strong beams and weak columns”and the over-reinforcement of rebar materials in the structure design through specific engineering projects have been analyzed;Some useful suggestions have been opposed for the amendments of standardized aseismatic design. A firm understructure for the following quantitative analysis of the causes of“strong column and weak beam”have been provided.