Dynamic Character And Damage Analysis To RC Frames Based On New Seismic Code In Earthquake Intensity Category Regions 8,9

"Code for seismic design of building"(GB 50011-2001) was put into execution on Jan. 1st 2002. And "Code for seismic design of building"(GBJ11-89) was abolished on Dec.1st 2002.A series of seismic fortification measures, such as limit of inner-story drift angle, minimum reinforced rate, column-beam moment magnification coefficient and moment magnification factor at the column base, etc. are improved in new seismic code. It is also necessary to verify by nonlinear dynamic analysis whether the seismic measures are effective and whether the predetermined earthquake- resistance aims can be achievable for frames in 8 and 9 regions. Different seismic response can be intuitively understood on inner-story drift angle, maximal topmost displacement, story displacement and plastic hinge distribution through time-history analysis. Seismic damage analysis may be a shortcut and prompt method and judge the comparative weak element and floor.Two representative reinforced concrete public frames were designed according to new codes in this paper, and nonlinear dynamic and seismic damage analysis were made by inputting ground motions at the intensity of fortification and rare earthquake actions. The slab-bars effect on yield strength of beams was involved in analysis. The conclusions are as following:①The element dimensions of frames in 8, 9 regions are mainly determined by inner-story drift angle. The minimum reinforcement rate has little effect on reinforcement in most columns of frames in 8, 9 regions.②No matter whether the slab-bars effect on yield strength of beams was taken into account or not, the frame in 8 regions responses on the small side by fortification earthquake actions, only a few plastic hinges appear in beam ends, and few plastic hinges in column ends. Seismic capacity behaves in rare earthquake action on the whole, but plastic hinges concentrate on column ends. Considering the bars in slab participate in beams against negative flexure, the frame demonstrates in a relatively unfavorable response.③ No matter whether the slab-bars effect on yield strength of beams is taken into account or not, the frame in 9 regions responses on the small side by fortification earthquake actions except El centro and Taft(Some plastic hinges appear in beam ends ). The structure in 9 regions demonstrates a favorable response under earthquake action and forms a well energy-consuming mechanism. It indicates that the seismic measures to 9 regions is effective and can achieve predetermined seismic aims. ④From dynamic analysis results of frames in 8,9 regions, frame responds equally by fortification earthquake actions No matter whether the slab-bars effect on yield strength of beams is taken into account or not. By rare earthquake actions, frame responds with slab-bars less, plastic hinges of beam is smaller, and hinges of column is bigger than those without slab-bars. ⑤Frames dimensions become bigger than those in literature[13].The frames based on new seismic code in 8,9 regions respond more favorably than those of literature[13]. ⑥The results demonstrate a relatively unfavorable response at column base in 8 regions under several inputs at the intensity of rare earthquake. It indicates that amplification factor of column moment at column base is relatively small. it is necessary to strengthen some involved seismic measures to better the unfavorable response. The structure in 9 regions demonstrates a favorable response under rare earthquake action and amplification factor of column moment at column base is accepTable . ⑦Story hysteretic energy dissipation varies in a wide range by time history analysis. It is concluded that the energy distribution becomes small from bottom to top. ⑧With regard to the contribution of the energy term to the value of the Park-Ang damage index, the damage indices are calculated for the elements of the frame structure under rare input motions while hysteretic energy dissipation factor is 0.05,0.10 and 0.25.It was found that for the typical value of (for detailed member...