By: Contech Engineered Solutions
This 30′ 8″ span x 9′ 8″ rise Deep Corrugated Box Culvert was chosen to replace an undersized 50 year old galvanized steel structural plate pipe arch. The existing pipe arch was still structurally sound after 50 years but needed to be replaced for fish passage purposes. Salmon species such as chinook, coho, pink, chum and sockeye salmon are all native to Mason County. The new deep corrugated box culvert has a wide enough span to carry the full bank width streambed inside of it. The deep corrugated box culvert was supplied with 6″ x 2″ corrugated steel structural plate headwalls and wingwalls that were reinforced with galvanized steel welded wire grid strips. In addition, the structure sits upon galvanized Steel Express Foundations that were infilled with concrete after the structure was in place.
From foundations to the top of the headwalls, this structure is galvanized steel and utilizes both 15″ x 5.5″ corrugations and 6″ x 2″ corrugations. The structure was both purchased by Mason County and installed with Mason County’s own road crew. The County was impressed with the speed of construction and the low number of days for the detour. The ability for counties to be able to purchase and install the structure themselves provides a cost savings to the Mason County residents.
The Steel Express Foundations were placed and secured in one day and since the crew had pre-assembled all the rings of the box culvert on the side of the road, the structure was completely assembled the following day by picking individual rings and setting them. The 6″ x 2″ corrugated headwalls and wingwalls were then installed in typical MSE installation sequence with reinforcing strips placed at regular lift heights, then well graded gravel was placed and each lift compacted accordingly. The ability to quickly construct a project on-site helps to protect the environment and allow safe passage for native fish.