Reinforced metal box culvert

In a reinforced metal box culvert having a length and being characterized by having a crown, opposing sides and opposite curved haunches, each said haunch being intermediate said crown and a corresponding said side, and spaced apart reinforcing members applied to exterior portions of said box culvert sides, haunches and crown, said box culvert crown, opposing sides and opposite haunches being of corrugated metal sheet sections which are of the same or different thickness in metal and having similar corrugated profiles, said metal sheet corrugations extending parallel to culvert span and said metal sheets being secured in nested overlapping relation, the improvement comprising:

• i) corrugated metal sheet reinforcement secured to at least said crown and extending continuously along said crown in the direction of the culvert length where such extension of sheet reinforcement is for a culvert length which is effectively supporting load,
• ii) said corrugated metal sheet reinforcement having a corrugation profile which abuts at least said corrugated crown with troughs of said reinforcement sheet secured to crests of said corrugated crown along said culvert length,
• iii) said corrugated metal sheet reinforcement having a curvature complementary to said corrugated crown to facilitate thereby securement of said troughs abutting said crests,
• iv) said corrugated metal sheet reinforcement extending continuously along said culvert length in an uninterrupted manner to provide an optimum load carrying capacity for a selected extent of reinforcement provided by said corrugated metal sheet reinforcement secured to at least said corrugated crown.