Increased Roughness in Reinforced Concrete Box Culverts

The purpose of this research was to determine the extent to which trapezoidal-shaped corrugations increased roughness and decreased water velocity within the barrel of a reinforced concrete box culvert. Steel bridge decking would be used as forms for pouring the concrete for the bottom and walls of the culvert during construction. Flow measurements were conducted in flumes using half- and quarter-scale simulations of the expected field corrugation size. Discharges ranged from 13.9-144 L/s and slopes ranged from 0-10.1 percent. Depths were measured using a point gage at seven different locations in both flumes. Sixty-eight tests were used to determine the Manning ‘n’ value. Manning’s ‘n’ was found to be inversely proportional to the submergence ratio and to the aspect ratio. Values ranged from 0.024 to above 0.060. Experimental errors ranged from 4.3-10 percent. Manning’s ‘n’ values for replication tests were within 3.2 percent of the original test. Velocities within the corrugations decreased 44-66 percent compared to upstream supercritical velocity. Hydraulic jumps formed in some experiments upon reaching the corrugations. The jumps are caused by the change in critical slope due to the increase in roughness. Simulation results from the Broken-back Culvert Analysis Program compared reasonably well with experimental results. The program suggests hydraulic jumps will often form within the corrugated outlet section of a broken-back culvert. It is recommended that several of these types of outlet sections be constructed in the field. This will reveal issues of constructability, which were outside the scope of this project.

Language

  • English

Media Info

  • Media Type: CD-ROM
  • Features: Figures; Photos; References; Tables;
  • Pagination: 13p
  • Monograph Title: TRB 86th Annual Meeting Compendium of Papers CD-ROM

Subject/Index Terms

Filing Info

  • Accession Number: 01046113
  • Record Type: Publication
  • Report/Paper Numbers: 07-0764
  • Files: TRIS, TRB
  • Created Date: Feb 8 2007 5:21PM