The Effect Of Cast-in-place Slab On Seismic Yield Mechanism Of RC Frame Structure

In order to achieve the seismic fortification target of No Collapsing in the Strong Earthquake, a philosophy of Strong Column Weak Beam is recommended in the current codes. However, actual earthquake disaster shows, this philosophy has not been realized, as the destruction of frame structure with’Strong Column Weak Beam’ occurred frequently in real earthquake. The research on the reinforced concrete frame structure shows that, in the process of design and analysis of the structure, the monolithical slabs are assumed to be rigid, and the effect of monolithical slabs are only considered by increasing the section stiffness of the beams, but while the effect of enhancing the flexural capacity of the frame is not counted in, which lead to the column-hinging damage in the real earthquake, following serious consequence.With regard to the phenomenon that the flexural capacity of the frame enhanced by the monolithical slabs makes the yielding mechanism of’strong column and weak beam’difficult to realize, this thesis conducted a thorough research on’effective flange width’and’column-to-beam strength ratios’through the following works:Firstly, the Pushover analysis is carried out on the basis of building the modes of different effective flange width to identify the effect of monolithical slabs on the yielding mechanism of the frame structures, and get the reasonable value of the effective flange width.Secondly, carrying on Pushover analysis on the basis of building the modes of different column-to-beam strength ratios,utilizing the effective flange width to approximate floor effect which is proposed in this paper. The reasonable value of column-to-beam strength ratios is obtained by analyzing distribution of the shear-top displacement curve, lateral displacement and the plastic hinges.Thirdly, time history method is used to analyze the effect of the column-to-beam strength ratios to the yielding mechanism of the column-to-beam. This thesis suggests the column-to-beam strength ratios must be further amplified while considering the affection of oblique direction earthquake.The results of this paper shows,in the process of the design and analysis of frame structure, the steels in the range of the effective flange width are suggested to take account to bear the bending which endured by the beam, and the corresponding column-to-beam strength ratios should be adopted to realize the philosophy of’Strong Column Weak Beam’.