Modeling of a concrete floor incorporating GFRP Stay-in-Place structural form

Abstract

A novel concrete floor design, featuring embedded glass fiber-reinforced polymer (GFRP) stay-in-place (SIP) forms adhesively bonded to the bottom flanges of GFRP I-beams has been developed. The paper presents a comprehensive finite element analysis (FEA) of this system with emphasis on the two orthogonal directions, namely perpendicular and parallel to the I-beam. The former incorporates the critical adhesively bonded connection which governs failure. The model incorporates material and geometric nonlinearities, appropriate interfacial and contact relations, robust failure criteria of the constituents, and was successfully verified using experimental results. The study showed that increasing the I-beam size by 33 % resulted in increasing the ultimate load (Pmax) by 25 %, mainly due to increasing the area of the adhesively bonded joint between the I-beam and SIP form. When mechanical fasteners were added to the connection, failure shifted to transverse rupture of the I-beam along its web-to-flange junction at a Pmax 1.8 to 2.8 times higher than that of adhesively bonded joint. A noticeable increase in cracking load occurred when the concrete strength varied 20 to 40 MPa, although led to slight change in Pmax due to failure still remaining by debonding. Increasing the slab thickness by 11 and 22 %, increased Pmax by 10 and 14 %, respectively, where debonding also governed. The floor behavior parallel to the I-beam was studied under different loadings and boundary conditions.