DESIGN METHOD OF TRIPLE CROSS-ARM PRE-TENSIONED CABLE STAYED BUCKLING-RESTRAINED BRACES
Peng Zhou 1* and Yan-Lin Guo 1
1 Department of Civil Engineering, Tsinghua University, Beijing, China
This paper proposes triple cross-arm pre-tensioned cable stayed buckling-restrained braces (TPCS-BRBs), where the stays are pinned to the external tube. Explicit expression for calculating the elastic buckling load of the TPCS-BRB is obtained in closed form through curve fitting, by adopting the finite element analysis (FEA) result on a generalized design parameter that can be deduced from a single cross-arm PCS-BRB (SPCS-BRB). It is found that two distinctive types of buckling modes might occur in the TPCS-BRB, namely single-wave symmetric and double-wave antisymmetric buckling modes. In addition, the load resistance of the TPCS-BRB subjected to monotonic axial load under antisymmetric buckling mode is explored through an elastic-plastic FEA. Corresponding lower limit of restraining ratio is obtained so that overall instability failures of the TPCS-BRBs would not occur by ensuring the cables not to become slack before the TPCS-BRBs reaching their ultimate states. At last, the effect of initial pre-tensioning force of the cables and initial geometric imperfection considering interactive imperfection on the ultimate load-carrying capacities of the TPCS-BRBs are investigated.
Triple cross-arm pre-tensioned cable stayed buckling-restrained braces (TPCS-BRB); Elastic buckling load; Initial pre-tensioning force; Interactive imperfection; Load resistance