Replacement or restoration are the options for dealing with Greenville’s closed Ohl Street bridge, according to an engineer who’s examined the 100-year-old span over the Shenango River.

Shawn Tunstall, project manager with HDR, Inc., Pittsburgh, presented design ideas to reopen the bridge, which was closed to all traffic on June 1, to Greenville residents Thursday night.

The ultimate decision on what to do with the bridge lies with Mercer County Commissioners, who took their regular business meeting on the road Thursday with a special session in Greenville. Depending on which way they go, it could be 2011 before the bridge is open again.

Tunstall, speaking at an informational meeting on the bridge held after the commissioners meeting, said the bridge can be torn down and replaced with an updated span, or the historic bridge can have its rusted supports replaced and the overall structure reinforced and renovated.

Laying down a new bridge is the cheaper option, Tunstall said, costing $2.3 million. Keeping the historic truss-bridge look on Ohl Street, meanwhile, would cost an estimated $3.8 million.

With a $1.5 million difference, Mayor Richard H. Miller and Greenville Council President Pete Longiotti both seemed to favor the cheaper option.

Nate Clark, Hempfield Township, took issue with the price difference. He said whenever other states examine whether to renovate historic bridges or replace them, the renovated bridges are usually cheaper. He asked why that was not the case on Ohl Street.

Tunstall said renovation can get expensive, since the replacement beams have to be carefully fitted and old ones reinforced. Building a new bridge can sometimes be much simpler and less expensive.

Replacing the Ohl Street bridge would let them go with a new style that doesn’t have the 16-foot clearance limitation, Tunstall said. A new bridge would probably last longer than the renovated version, he said.

Clark pointed out that with the bridge on Main Street, clearance isn’t an issue and tall trucks could take that bridge. He also suggested that better upkeep of the bridge, including painting it properly and more often, could make it last longer.

Proposed replacements would also feature the pedestrian walkway that is also closed on the Ohl Street Bridge. If it were re-built, a blind spot from the eastbound approach that prevents seeing past the end of the bridge could also be eliminated, Tunstall said.

Miller said a decision should be made soon. The town could be in deep trouble if there’s an accident or event that shuts down the bridge on Main Street, said Miller. The Ohl Street bridge is the only other east-west crossing of the Shenango in the borough.

The next-nearest river crossings are on Porter Road in West Salem Township or Wasser Bridge Road in Hempfield Township.