Structural Behavior of Concrete Box Culverts under Deep Burial

Culverts have been used to transmit surface drainage under roadways in place of typical short-span bridges because they provide an economical construction system. In this paper, a numerical study using a finite-element method is presented to study the behavior of reinforced concrete box culverts (CBC) with different dimensions and thicknesses under different soil fill heights. Four box-culvert sections were selected with width-to-height ratios of $2:1$, $1:1$, $2:3$, and $1:2$. Each section has a constant clear hydraulic area of $6.7\times {10}^6{\mathrm{mm}}^2$. Different thicknesses of CBC were investigated for each section. Hyperbolic stress-strain parameters for nonlinear finite-element analysis in soil masses were used. The required area of steel and deflection of culvert were calculated from each finite-element run. It is concluded that the CBC with a width-to-height ratio of $2:1$ is suitable for all soil fill heights examined (4.6, 9.1, 13.7, and 18.3 m). Finally, the paper presents a simple linear regression formula to predict section thickness for any soil fill height when using CBC-1.