Isostatic and frictional energy dissipating connecting systems for UHPC curtain walls: Design and experimental validation

Abstract

Ultra-high performance concrete (UHPC) curtain wall is a new type of non-structural building envelope component. Given its large size and high cost, rational connecting systems should be employed to prevent potential seismic damage and economic losses. In this study, two novel connecting systems, including an isostatic connecting system and a frictional energy dissipating connecting system, were proposed for reinforced concrete (RC) frame with UHPC curtain walls. The design methods for these two connecting system were provided first. Then, to evaluate the feasibility of the proposed connecting systems and the corresponding design methods, three 1/2-scale RC frame structures (i.e., one bare frame without curtain walls, one with isostatic curtain wall connecting system, and one with frictional energy dissipating curtain wall connecting system) were designed and fabricated for pseudo-static tests. The damage evolution, failure mode, strength, stiffness, and energy dissipation capacity of the three test substructures were assessed. The test results demonstrated that through reasonable design, independent rocking deformation of the curtain walls was achieved in both the isostatic and frictional energy dissipating connecting systems, allowing the curtain walls to remain free from damage even under an inter-story drift of 1/36, thus validating the reliability of the proposed connecting systems and design methods. Further, compared to the bare frame, curtain walls employing the isostatic connecting system exhibited a negligible effect on the seismic performance of the frame. On the contrary, curtain walls employing frictional energy dissipating connecting system effectively enhanced the strength and energy dissipation capacity of the frame, allowing dual damage control for both walls and frame. Consequently, the frictional energy dissipating connecting system is considered to be a more rational method for enhancing the seismic performance of buildings.