Effectiveness of buckling restrained braces for upgrading earthquake resistant capacity of single layer grid dome

This study investigates the effectiveness of buckling restrained braces (BRBs) adopted for reducing dynamic responses of a grid dome to severe earthquakes. The diameter of the dome is 120 m of a circular plan. The dome is supported by a ductile substructure composed of BRBs, and the substructure is proportioned so as to initially yield under a base shear coefficient of approximately 0.30 and to bear a base shear coefficient of 0.40 against earthquake motions of the ultimate limit state. Artificial seismic accelerations based on a design spectrum specified in a Japanese code are applied in the present analysis. The intensity of the applied accelerations ranges from the serviceability limit level to the ultimate limit level. The results of responses have provided us with valuable information indicating that the ductile substructure of the dome absorbs seismic energy with a stable hysteresis loop, significantly decreasing the responses of the dome. The responses also show that the dynamic amplification within the dome is greatly suppressed in comparison with those in domes supported by elastic substructures. A formulation for the response reduction rate is proposed. The present paper clearly indicates the feasibility of constructing large reticulated domes of this type in regions prone to severe seismicity using such BRBs.