| Stress of joint core under seismic action is very complex and is usually the weak part inthe concrete structure seismic system; it is a necessary condition to ensure the structurefunctions properly that the node works safety and reliability. Domestic and foreign scholarshave carried out extensive research for the seismic performance and design methods ofreinforced concrete frame joint, and have achieved fruitful research results. In recent years,with the numerical simulation technology of structure in the gradual maturity of engineeringapplications and development, the preparation of computer-based finite element program,through the establishment of the node model to simulate the joint core by the impact of theearthquake to be an effective means.Previous earthquake damages at home and abroad show that the destruction of most ofthe reinforced concrete frame structure begins with the end-column plastic hinge, the expected"strong column-weak beam" and failed to achieve objectively. The reason is that the currentspecification does not fully consider the contribution of slab to resist the negative momentcapacity of frame beam in the seismic design of reinforced concrete frame joint. For practicalframework bending capacity of longitudinal beam is "over strength", the current specificationof "strong column-weak beam" design provisions of the code, only to a certain extent slowdown the yield of the column ends and can not really achieve the criteria. Therefore, exist ofcast-in-place slab to the failure mechanism of reinforced concrete frame structure can not beignored.In the calculation and analysis of the frame structure, especially under the strongearthquake and "strong column-weak beam" mechanism, traditional assumption of rigid jointis no longer applicable. Consider the impact of the slab to mechanical behavior of thereinforced concrete frame beam-column joints, and further proposed a seismic designmethods of frame joint which considers the impact of slab is one of the important issues needto be lucubrated. In order to analyze this problem, this paper mainly to do the following work:①Use of the open-source finite element software OpenSees numerical simulationanalysis of reinforced concrete frame joints, contrast experimental results and simulation results to verify the accuracy of the program to simulate；②Slab can improve the stiffness of beam and bearing capacity of beam end. It isunfavorable to achieve the design principles of "strong joint-weak member" if cast-in-placeslab is not to be considered in the design. Take the exterior joint as a model, consider theimpact of cast-in-place slab, modeling analysis of the joints of different effective flangewidth；③Contrast to the numerical analysis results of every model to study seismic behavior ofreinforced concrete frame joints considering the impact of slab under low repeated reciprocalloading and take suggested value method of frame beam effective flange width. We suggestthat the T-shaped section joint effective flange width considering cast-in-place slab to be14／45floor calculation span, and table a proposal to design procedures of frame jointsconsidering cast-in-place slab. |
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