A deficient bridge in OKC might cost $10.5 million to replace. Engineers say it's worth it.

Oklahoma City engineers presented preliminary design reports for a $10.5 million project to replace a deficient bridge carrying N May Avenue over Northwest Expressway to city council members Tuesday.

The two roads connect one of the city’s busiest shopping destinations, including Penn Square Mall, and large employers, including Integris Baptist Medical Center.

The bridge's height limit is lower than modern standards, and it has partially collapsed at least twice when trucks hit crossing beams.

The spending limit for city funds on the new bridge's construction is capped at just under $4.35 million, but planners have worked to secure additional grant funding of $6.36 million through the Association of Central Oklahoma Governments.

The project would replace the current bridge with a 260-foot long and 75-foot wide steel I-beam span bridge, implementing what is known as a "diverging diamond interchange" engineering design. Other proposed improvements include reconstruction of the on- and off-ramps; new traffic signals for a new intersection at the crossover traffic point; building a 10-foot trail along the center of the bridge; and adding ADA-compliant sidewalks, bridge rails and traffic parapet barriers.

Public Works Director Debbie Miller said city staff and engineering consultants researched less expensive options, but the $10.5 million proposal was the option city planners recommended because it would offer the biggest improvement to traffic safety and because it was the only one the association grant would support.

Miller said plans should be finalized in late 2024 and construction should begin in 2025.

More: Oklahoma City to replace May Avenue bridge over Northwest Expressway citing safety concerns

Councilperson James Cooper, who represents Ward 2 where the replacement project will occur, said he is also supportive of the proposal because of its potential to further improve sidewalk connectivity plans already underway for pedestrians around Northwest Expressway. Final specifications for those sidewalk plans are expected this summer, Miller said.

"Imagine being able to walk from Target at Expressway and May and be able to safely go down on the sidewalk infrastructure we would create onto Northwest Expressway, to get to the BRT station, for example, in front of the OAK," Cooper said.

The preliminary design reports list additional advantages. The diverging diamond interchange plan has fewer "conflict points" between vehicles, pedestrians and bicycles, shorter traffic signal phases, and the wider bridge also would allow for more support columns between footings already existing at the site.

Existing May Avenue bridge has history of collapsing

Built in 1952, the current May Avenue bridge has a height limit of 14 feet and 4 inches and is lower than modern standards. Voters approved a bond election in 2017 allocating funds for the bridge replacement, with sidewalks and lighting listed for inclusion in the project, as well.

The existing bridge has a history of serious issues. Its northbound lanes collapsed on May 19, 2016, when a truck hauling construction equipment hit the bridge and destroyed three beams. The accident caused one 52-foot span to collapse onto the road underneath it.

Police said the truck was carrying two boom lifts after the driver had delivered one to Penn Square Mall. A witness said the boom on the remaining lift had been raised and was not lowered before the driver left the mall and drove west on the Northwest Expressway toward the bridge.

More: May Avenue bridge needed repairs before 2016 collapse, reports reveal

At the time of the accident, around 22,000 vehicles crossed the bridge daily and 39,000 vehicles traveled underneath on Northwest Expressway. But no one was injured because of the collapse, and Sunbelt Rentals, the company that owned the truck, reimbursed the city for more than $575,000 of repairs.

An investigation by The Oklahoman after the 2016 bridge collapse revealed concerns about the structure going as far back as 1982, when inspectors first noted "considerable" damage to support beams hit by vehicles too tall to pass under the bridge. The Oklahoman also reported a bridge section previously collapsed when it was hit by a truck hauling a backhoe in 1993.

The bridge was rated as deficient by inspectors for a decade before the 2016 incident. The designation means a bridge is safe for traffic, but a component, or the bridge in its entirety, requires repair or replacement.

Approval of the preliminary reports for the bridge replacement was passed unanimously by city council Tuesday. CEC Corp., who was selected by the city's Public Works Department to design the project, hopes construction will be completed by summer 2026.

Related: Are Oklahoma's structurally deficient bridges safe for motorized traffic?

This article originally appeared on Oklahoman: OKC to replace deficient May Ave.-NW Expressway bridge in $10.5M plan