Structural Evaluation of Box Culverts

Abstract

Corrugated‐metal box culverts are employed as replacements for short‐span bridges. As a result of increasing use, there is a great demand for establishing a rational design procedure for these culverts. The available design procedures are based on experience or mathematical modeling. Only a limited number of attempts have been made to verify these design techniques with full‐scale field tests. Three corrugated‐metal box culverts were fully instrumented and field‐tested under similar backfill conditions and live loads. The first culvert was bulb‐angle‐rib‐reinforced corrugated aluminum; the second was rib‐reinforced corrugated steel; and the third was corrugated‐rib‐reinforced corrugated steel. The collected data were evaluated using a finite element analysis, and the applicability of standard design parameters was determined. Maximum bending moments obtained from field tests were compared to plastic moments calculated according to American Association of State Highway and Transportation Officials (AASHTO) specifications. It was concluded that the design for these types of structures can be improved if (1) Composite action is assumed; (2) thrust forces are included in design; and (3) construction procedures are controlled. The AASHTO specifications were conservative for rib‐reinforced, corrugated‐metal culverts.