Study On Influence Factors Of "Strong Column And Weak Beam" Of Rreiforced Concrete Frame Stuctures

In order to ensure the seismic performance of reinforced concrete frame structure, it requires that the structure can realize "strong column and weak beam" under seismic action. The "strong column and weak beam" mechanism is that the plastic hinges in the beam should appear before the column. It’s not allowed to appear plastic hinge at both of top and bottom-side of the same column. However, the destruction of the columns of numerous frame structures is in the form of a serious plastic hinge, and that of the beams is lesser. There are many factors which cause frame failed to achieve "strong column and weak beam" yield mechanism. The inconsiderateness of the strengthening effect of the cast-in-situ floor slabs towards the frame beams is the main reason. Meanwhile, Limit values of axial compression ratio and beam section height affected the "weak beam strong column" mechanism. This thesis focuses on these factors and does the following aspects of work:(1) It has analyzed the main seismic destruction of the frame structures in earthquake, and summarized the main factors of "strong column and weak beam". It introduces the current situation of research on "strong column and weak beam" influence factors both at home and abroad.(2) With the aid of the structural analysis program SAP2000, two typical frame models of frame model without floor slabs and frame model with floor slabs are established for pushover comparative analysis. By considering the effect of floor slab and comparison of Pushover analysis of frame structures, this thesis investigates the effect of in-situ floor slabs on the seismic performance of structures. It indicates that the structure of three-bay frame considering the effect of floor can be achieved "weak beam strong column" mechanism of yield when the end-column moment magnification factor increases to1.5. Meanwhile, some suggestions of structure seismic design are put forward.(3) Studying on limit values of axial compression ratio and considering the effect of beam section height, the influence of "strong column and weak beam" yielding mechanism has been determined. The seismic performance of the flat beam frame has been analyzed. This thesis also studies the distinguish formulas with "weak beam strong column".(4) Contacting earthquake instances, this thesis analyzes the reasons that the structure did not realize "strong column and weak beam" yielding mechanism.