Seismic Response of Three-Dimensional Pultruded GFRP Frames

Abstract

This paper presents the first seismic tests on a full-scale all-composite frame structure, constituted by pultruded glass fiber–reinforced polymer (GFRP) profiles, to the best of the authors’ knowledge. These tests were performed in the scope of the FRP-Quake project, which aimed to provide an in-depth understanding of the dynamic and seismic behavior of all-GFRP structures, and to develop structural systems with adequate seismic resistance. Therefore, an extensive research program was conducted, from the material and component scales to the structural full-scale, which encompassed the development of appropriate beam-to-column bolted connection systems. The experimental campaign presented in this paper was composed of shaking table tests on a full-scale, two-story, three-dimensional (3D) frame of I section pultruded GFRP profiles connected with bolted stainless steel parts. First, modal identification tests were performed, which show the influence of adding floor masses, bracings, or both on the dynamic characteristics of the structure, which were accurately predicted with relatively simple linear finite-element (FE) models. Then, the frame structure was subjected to 18 base displacement histories with increasing intensity, which was based on the design earthquake for mainland Portugal. The results showed that the structure maintained its integrity for intensities up to 37% higher than the normative requirements. This showed the feasibility of using this type of all-GFRP structures in seismic areas.