Study and application of seismic energy dissipation bracing system in Expo Center

Buckling restrained brace frame(BRBF) is a system with prominent seismic energy dissipation.In this paper,analysis was conducted to study the main design principles for BRBF including structural seismic performance,layout of BRB,design of BRB and joints,criteria of BRB products.Low cycle loading tests of full scale BRB were performed to illustrate that the hysterics behavior for BRB used at the Shanghai Expo Center is good enough to satisfy the product criteria.Test results also show that BRB capacity increases because of the strain harden and compression.It is found that BRB produced by different companies may show different behaviors,and a uniform criterion is necessary in the application.Pushover analysis and elasto-plastic time history analysis are carried out to obtain the plastic deformation and structural forces under earthquake.Both analytical results indicate that with reasonable layout and design,BRB can dissipate energy and result in the whole structure with good seismic behavior.