Nonlinear Finite-Element Modeling of Concrete Bridge Girders Prestressed with Carbon Fiber–Reinforced Polymers

Abstract

Concrete beams (girders) prestressed with steel cables are widely used in highway bridges. The prestressed steel cables are prone to area loss due to corrosion. The high stress level and deteriorated bond due to corrosion further risks the structural integrity of these beams. Therefore, corrosion-resistant fiber-reinforced polymer (FRP) reinforcement has been investigated as a substitute for prestressed steel in pretensioned concrete beams. While generating data on such members, especially at a large scale, is a slow and costly affair, validated finite-element models (FEMs) can be leveraged to accelerate the process. This paper presents an FEM strategy for carbon fiber–reinforced polymer (CFRP) prestressed beams that is convenient yet sufficiently accurate. A series of AASHTO Type-I beams with a composite deck were previously tested by the authors and the data from those tests were used to validate the developed FEM approach. Thereafter, a parametric study was conducted using the developed FEM, and the results were used to investigate the behavior of such pretensioned concrete beams beyond the scope of the experimental work. The investigated parameters included prestress ratio, modulus, and reinforcement ratio of the prestressing CFRP reinforcement, and the properties of the concrete and the composite deck. The influence of these parameters on the cracking load, precracking and postcracking stiffnesses, flexural capacity, and maximum deflection of the beam was examined. The results indicate that the prestress ratio influences the cracking load and deflection in CFRP-prestressed beams, with FRP properties affecting postcracking behavior and failure modes. The tensile strength and rupture strain of FRP, respectively, affect the bending capacity and deflection, while the concrete properties have a minor impact on the beam behavior.