A new engineering study has revived hope for the Murray Morgan Bridge, suggesting that the Tacoma landmark can be fixed for less than the cost of replacing it.

That’s a welcome surprise for the bridge’s many fans. When the state Department of Transportation closed the badly corroded span in October, its condition sounded terminal. DOT engineers were worried some key component might fail and cause the entire structure to collapse.

At the time, at least some of those engineers believed the Murray Morgan was beyond repair.

But the City Council asked for a second opinion from David Evans & Associates, an engineering consultant firm with special expertise on bridges. Its full report won’t be out for a couple weeks yet, but a newly released cost summary prices a major rehabilitation at $80 million.

That compares to a 2004 estimate of $135 million for a complete replacement. If $80 million can actually deliver an overhaul that meets the city’s needs, it could save money and preserve a big piece of Tacoma’s heritage in the bargain.

That hope is prefaced with an “if.” Because the full Evans report isn’t out, we don’t know how completely the Murray Morgan might be restored with the $80 million.

Undoubtedly, the bridge would again be safe and reliable – but for how long? When the Murray Morgan was constructed, in 1911, bridges were generally engineered to last 50 years. So it did very well to make it 96 years.

But an overhaul doesn’t start the clock all over again. In some cases, rehabilitation will give an old bridge only another 15 or 20 years of life. It’s safe to assume Evans has something far more enduring in mind, but another 50 years might be a push.

By comparison, today’s bridges are designed to last upwards of 75 years – and can easily go well over a century. The $80 million vs. $135 million comparison could take on a different light when the projected lifespans are factored in.

Another unanswered question has to do with maintenance expenses. The City of Tacoma would be fully responsible for maintaining the bridge after the overhaul is complete. The money to do that may well have to come out of the same Public Works Department fund that already struggles to cover ordinary street repairs. Some painful sacrifice would have to be made.

If the upkeep on a restored bridge doesn’t run much more than on a new bridge, there’s no issue. If it’s substantially more, it could drain funds that are already inadequate. This question, too, might be answered by the full report.

But if all things were more or less equal, it would be much preferable to preserve this immense symbol of Tacoma’s history. That tantalizing $80 million figure suggests such a rescue might just be possible.