The Cyclic Behavior of I-Shaped Steel Deep Beams Reinforced with CFRP

Abstract

This paper presents the flexural cyclic behavior of I-shaped hot rolled steel deep sections used as beams in moment-resisting frames (MRF) featuring a carbon fiber reinforced polymer (CFRP) patch on the web through advanced finite element analysis. The main goal of the CFRP reinforcement is to increase the rotation capacity of the member without increasing the overstrength to avoid compromising the strong column-weak beam condition in MRF. A reduced finite element model of a steel beam is developed and validated with experimental data. The CFRP patch is modeled considering fracture in the adhesive layer using the cohesive zone modeling (CZM) technique that can capture the crack initiation and propagation. Different adhesive types are investigated where the CZM parameters are calibrated from high fidelity fracture mechanics tests that are thoroughly validated in the literature. This includes a rigid adhesive commonly found in the construction industry and two tough adhesives used in the automotive industry. The results revealed that the CFRP patch can increase the rotation capacity of a steel member considerably when using tough adhesives. (c) Tongji University Press 2024.