Prediction of deflection considering cracking and temperature gradient effects in steel-concrete composite girders

Abstract

Steel-concrete composite (SCC) girders are gaining popularity in the construction industry due to their ease of rapid construction and higher span-to-depth ratios. Simply-supported SCC girders are widely used in flyover and railway over bridges to avoid traffic disturbance during construction. The present paper considers an SCC girder consisting of a concrete slab and steel girder integrated together to resist stresses through composite action. The cross-section of SCC girders is slender, hence they would be susceptible to serviceability criteria like deflection and cracking. From the comprehensive literature survey, it has been deduced that the thermal stresses due to the temperature gradient effect play an important role in inducing concrete cracking and a further increase in deflection. In the present study, the explicit equations are derived to predict the thermal stress distribution across the cross-section. Further, the equations are also derived for the mid-span deflection considering concrete cracking in addition to temperature gradient effects. In order to validate the results obtained from the proposed equations, the finite element (FE) models are developed. The results obtained from the equations and FE models are compared and found within an acceptable limit for everyday design purposes. The explicit equations significantly reduce computational time compared to the finite element analysis (FEA). Copyright © 2025 Techno-Press, Ltd.