Inelastic Seismic Analysis Estimate Of Reinforced Concrete Frame-shear Structures

As population density of our cities is larger and larger, frame -wall structures become one kind of RC structures used widely in earthquake regions in China. According to the code for seismic design of building in China, structructures are built by the results of frequent earthquake in elastic state, assure structures'necessary ductility and hysteretic energy-dissipated capacity, make them dissipate stably earthquake energy through inelastic deformation and keep their carrying capacities to vertical loads and the stabilities as a whole under higher earthquke action levels. Six RC frame-wall structures under 60m and located in four different Intensity Regions were selected in this article, and designed exactly according to The Code for Design of Concrete Stuctures,The Code for Seismic Design of Buildings and The Technial Specification forConcrete Stuctures of Tall Building, after the design working to be completed, these nonlinear dynamic response analyses of corresponding structures imposed on rare earthquke are carried out in SAP2000. According to the analyticl results, improvement suggestions are proposed though the submitted status and the sequence of yielding members of the structures, make the expensive structures reach expecting functions in probable earthquake in future, so as to ensure people's life property safety. To attain these objectives, analyses in this article are conducted as following:(1)Six sixteen-story frame-wall stuctures were choosed and designed in term of the provisions prescribed by Chinese codes, one located in Intensity Region 7(0.1g), one located in Intensity Region 7(0.15g), two located in Intensity Region 8(0.2g), two located in Intensity Region 8(0.3g).(2)The acceleration-histories at rare earthquakes level were imposed separately to the six structures and the nonlinear dynamic response analyses conducted, and mainly focus on displacement response,distribution of plastic and the shearwall's seismic shear performance, so as to study every model's response behavior.From the evaluations and discussions of the results presented in this report, the main specific conclusions are given below:(1)Six structures'total seismic performance seems to be fine, the two located in Intensisty Region 7 are not yield, some members of the four located in Intensisty Region 8 are yield.(2)According to the analytical results, it is found that the hinges in coupling beams were appeared at first, but the external columns of sheal-wall were yield at first,these phenomenna don't acord with seismic conceptual. So this article proposed to impove the bending resistance of the the external columns of sheal-wall by enhace the reinforce ratio.(3)Beacause the stiffness of shear-wall is larger, the frames are favorable. The top columns of frames are the easiest menbers to be yield at rare earthquakes level , it is propsed to strengthen the aseismic measures of the top columns.(4)The analysis of two groups with the stiffness of cupling beams reduced and not reduced show that, the displacement response of the structures with cupling beams whose stiffness is reduced is relatively large,but the characteristics of the dynamic response of these structures do not change essentially, the internal force of the structures with cupling beams whose stiffness is reduced is significantly reduced, but the internal force of the structures with coupled-beams whose stiffness is reduced does not change significantly. So this article proposed to increase coefficient of the cupling beams'stiffness in engineering design so as to decrease the internal force of the cupling beams.(5)The response shear forces of the first story walls and those of the walls in the story above the bottom strengthening regions in some strctures located in Intensisty Region 8, exceed the shear forces enhanced. This article proposed to enhaced magnification coefficient of shear force in the first story wall.