An innovative approach to determine deck pavement modulus and interfacial slip stiffness based on a composite beam model

Pavement modulus and shear slip stiffness are two important parameters in determining the mechanical behavior of steel deck pavement. This paper proposed a new method to estimate these two parameters based upon elasticity and composite theory. A composite beam model with incomplete shear interaction was first established, from which equations for calculating beam deflection and pavement strain were deduced in terms of pavement modulus and shear slip stiffness. The equations were solved by a numerical approach to analyze the effect of parameters on deflection and strain distribution. Analytic results indicate that the influence of pavement modulus on strain distribution along beam depth at the mid-span section is more significant than that of the interfacial shear stiffness, but within the same order of magnitude. Moreover, the slip strain increases with the reduction of pavement modulus or shear stiffness. To verify the proposed model, a bending test was conducted on a steel deck–pavement composite beam at normal temperature. Based on the proposed method, a numerical back-calculation approach—discrete search iteration approach was established with detailed flow chart. Pavement modulus and shear slip stiffness were back-calculated from the test results of displacement and strain. It shows that pavement modulus is higher when shear slip along the deck–pavement interface is considered than that when shear slip is not considered. It was further concluded that pavement strain distribution could be predicted more realistically using the slip stiffness together with the exact pavement modulus. This study improves current simulation method of the behavior of a steel deck–pavement composite structure. The exact shear stiffness calculated based on the proposed method can also provide an index for bonding evaluation.