Officials of the city of Butler were understandably troubled to learn the disturbing secret about the bridge — currently closed — at the corner of West Penn Street and North Sixth Avenue.

Based on a report John Evans, city zoning and code management officer, presented to the city council on April 23, the bridge’s concrete deck was found to contain about 80 percent fewer reinforcing steel bars than what should have been used in constructing the span.

That weak construction could have been a prescription for collapse at some point.

The bridge construction reflects a time when the small Bantam cars were popular. But the Bantam era is long past and the city’s infrastructure must reflect the changes that have occurred since — although many of the city’s streets seem Bantam-width.

Questions remain as to how and why the improper construction occurred. Did city officials of the time merely put their trust in those who built the span, without any supervision or engineering expertise to oversee the project?

Did city leaders of the time when the bridge was built opt for a cheap project?

The best explanation might be found in the fact that construction standards then were not as stringent as they are now.

The bridge, which had a 4-ton weight limit, was closed in February after an inspection by the state determined that it was structurally deficient and safe only for vehicles weighing less than 3 tons. The inspection found corrosion in one of about 15 steel beams, but the potentially more dangerous problem turned up after city crews removed the bridge’s blacktop and milled down its deck, revealing the improper construction.

The cost to repair the bridge is estimated at about $74,000, while full replacement of the bridge deck, sidewalk and rails will cost about $135,000. The city’s plan to do the latter makes sense.

According to Evans, the cheaper option would leave the city with a weight-restricted bridge rated at 8 tons. That wouldn’t make sense considering an added cost of just $61,000.

Putting the emphasis on the North Sixth Avenue work will require some shuffling of money between projects by city officials, but the reallocation of funds would be a good investment.

Having the North Sixth Avenue bridge closed until late fall is a long inconvenience for many who use the street. But having it repaired properly is the right course of action.