Research On Slab's Influence To "Strong Column Weak Beam" Yield Mechanism Of RC Framework

In the design of building structure, the frameworks in the earthquake show the yielding failure mechanism of "strong column weak beam" is expected to achieve the form of structure destruction, but this kind of damage form is not realized in the actual earthquake damage.Through research and analysis of the collapsed buildings after the earthquake, and find that considering the influence of the cast-in-place floor on the reinforced concrete frame beam is not sufficient and accurate enough that is the important reason which cause the structure unable to achieve the goal of "strong column and weak beam". Based on six floors reinforced concrete frame as an example in this paper, the seismic performance of reinforced concrete frame structure is studied,mainly explore the effect and influence of cast-in-place floor on the failure mechanism of reinforced concrete frame structure "strong column and weak beam". In this paper mainly do the following aspects of research:(1) First of all, understand the background which the framework is not able to achieve the damage form of "strong column and weak beam", and on the relevant theoretical research carry on the data collection and inspection. Through the analysis of domestic and foreign research present situation, preliminary explore the influence of cast-in-place floor slab on the yield failure mechanism of frame structure.(2) Establish a pure frame structure model 1 without floor and a frame structure model 2 with full floor respectively, through the modal analysis and Pushover analysis, and it is concluded that the floor will have a great influence on the mechanism of "strong column and weak beam" when the frame is destroyed.(3 ) In order to determine the scope of the cast-in-place floor slab's influence on the frame structure, and namely determine the value of the effective flange. Based on the principle of energy variation, carry out theoretical calculation, and obtain the value of the effective flange. In addition, estabilish three kinds of frame structures with different flange width, and the flanges width are taken respectively of 3 times, 6 times and 9 times at the end of each side of the beam. carry on the modal analysis which obtains the stiffness change of the new three kinds of frame structure, and compare with the results obtained by the frame structure model 1 and 2.(4) Pushover analysis is carried out on the new three frame models which consider different effective flange. According to the trend of changes of the base shear-top displacement curve, floor displacement curve and storey drift curve, and the development and change process of plastic hinge at the end of the columns and beams of three kinds of frame models so as to obtain the influence range of floor. Combine and compare with the result of theoretical analysis so as to get the value of the effective flange width in the background of this project.(5) Other influencing factors are considered and compared with the finite element analysis according to the existing test results. Based on the previous results,and put forward the formula of the flange of the floor slab under the influence of different factors.