Research Of Earthquake Resistant Capability For Irregular RC Frames With Buckling Restrained Braces

Because the concentrically braced frame can offer older resisting stiffness to structure, widely used in high seismic region. But the commonly used steel brace buckling when pressure, especially in the back and forth under the earthquake supporting components after repeated compression buckling stiffness and bearing capacity of a sharp decreased. In order to address this traditional problem, after many years of research, related to academics develop a brace which could avoid buckling.called unbonded braces, also known as buckling restrained brace. The Buckling-Restrained Brace(BRB)is a new kind of brace focusing on the solution to the problems associated with buckling. The concept of the BRB is the buckling prevention of the central steel core by encasing it over its length in a steel tube filled with concrete. The compression and tension loads are designed to be carded only by the core by means of unbonded layer to allow the free slip between the core and the surrounding concrete. The BRB can reach and retain fully sectional yielding of the core under compression. In stronger earthquake, it exhibits stable and predictable hysteretic behavior, provides significant energy dissipation capacity and is an attractive alternative to protecting frames. After strong shock, the inelastic distortion of main structure is small, it is easily to replace the broken braces.The several analyses have done:1. This paper is studied for irregular RC frame which is stiffness-insufficient and torsional rigidity-insufficient in high seismic region and provides a design process of the buckling-restrained braces. Proposed formation a new support system of reinforced concrete frame by add buckling restrained braces,in order to meet Story drift and torsional period ratio;2. According to the formulae for Story displacement of irregular RC frame in torsional effect, and based on the my study achievements, proposed a design cycle which is used to reinforce irregular RC frame by add buckling restrained braces.3. The results of proposed method are analyses, and three different seismic waves is used to simulate in time-history analysis method by software ANSYS.4. The layout of buckling restrained braces will affect the damping effect and torsional period ratio of structure. There are no uniform method to determine the optimal layout, the text proposed two principles to be followed, and the low-level earthquake waves is used to simulate in time-history analysis to analyses the result of layout.The results show that:with the addition of buckling restrained braces significantly improved the torsional properties of the irregular RC frame. There is decreased substantially in the torsional period ratio and torsional displacement ratio of frame. In strong earthquake, buckling restrained braces exhibits stable and predictable hysteretic behavior, energy damping effect significantly. By comparative study of different models, summed up the buckling restrained braces'layout principles, the influence of different layout are gained in this paper and according design suggestions are given. The result of this paper will redound to generalize the Buckling-Restrained Braced Frames.