Modification of Moment Equations in the CHBDC (2000) for Soil-Metal Box Structures

Abstract

This paper evaluates the moment equations in the 2000 Canadian Highway Bridge Design Code (CHBDC) for soil-metal box structures, which are applicable to spans less than 8 m. Finite element analyses are carried out for soil-metal box structures having spans of 4-15 m using the deep corrugated metal plates under three construction stages: backfill up to the crown, backfill up to the cover depth, and live loading. The coefficients of moment equations are newly proposed based on the results of numerous finite element analyses considering various design variables, such as span length, soil depth, and backfill conditions. The validity of the proposed coefficients in the moment equations of the CHBDC (2000) is investigated and compared with the existing coefficients and numerical results of finite element analyses. The comparisons show that the moments of the CHBDC (2000) give good predictions for spans less than 8 m, but underestimate them for spans greater than 8m. In contrast, the proposed moments give good estimates of numerical results for the spans of 4-15 m.