A Primary Review Of Code Designed Irregular Reinforced Concrete Frame About The Anti-torsion Security

The torsion effect is an important factor to cause the seismic damage of structures, so it has always being an important problem in seismic research area all through. But the translation-and-torsion coupling vibration of structure is a three-dimensional problem, and the experimentation is limited to the size and quantity, so the computer simulation becomes the main means to study the torsion effect. As to the irregular structure, only the first step of design is really performed according to the Chinese code for seismic, and the structures' response under the fortification and rare seismic action need to be reviewed through some three-dimensional nonlinear analysis quantificationally. This paper firstly compares the provisions about torsion effect and anti-torsion design in several codes (the old and new Chinese code for seismic, and some other countries' codes). Then, according to the code for seismic design of buildings (GB50011-2001) and the code for concrete structure design (GB50010-2002), the paper designs two multi-storied irregular concrete spatial frames, which respectively situated at the area of fortification intensity 8 and 9. Subsequently, using the program based on the column-beam element of fiber model, input several ground motion records, which are selected according to the demand of code, to carry the structures' three-dimensional nonlinear analysis in two perpendicular directions at the same time. In the end, the paper sums up the calculation results, and reviews the whole performance of this type of structures under earthquake actions. Except that, it reviews the structures' security about the translation-and-torsion coupling response under the fortification and rare seismic actions, and gives a primary evaluation; it also discusses some characters of the structures' three-dimensional nonlinear response of torsion under earthquakes.