Q&A | Top engineer: Maintain existing bridges
PITTSFIELD — The following is a Q&A with Alexander K. Bardow, the state’s top bridge engineer.
QUESTION: Has a structurally deficient bridge in the state of Massachusetts ever been the cause of a death or injury?
ANSWER: No. That’s one of the things we pride ourselves [on].
Q: If a bridge is structurally deficient, why is it still safe to drive on?
A: If the condition is serious, we will inspect it every six months. If [inspectors] see something unsafe, then they would recommend immediate closure.
Q: What are examples of things that would trigger an immediate shutdown?
A: If an inspector saw that the deck was basically crumbling ... if there’s so much corrosion that a beam no longer has capacity to carry any weight.
Q: Are you up to date with the two-year bridge inspection schedule?
A: We’re up to date. The Federal Highway Administration oversees our inspection program and they have 23 metrics they judge by and there’s not that much leeway as to how much an inspection can slip.
Q: How are “scour critical” bridges monitored?
A: We put these placards on the structures, red over yellow. When the water level rises to the interface between the red and yellow, that’s an indication that the water has risen to a depth that scour may start to occur. Local and town officials, with very simple monitoring, can look at water elevation, and they can close the bridge as a precaution until an evaluation. We don’t have that many “scour critical” bridges in the Commonwealth.
Q: Do “scour critical” bridges get priority attention?
A: They get an extra factor applied to their health index, so it bumps them up to a higher prioritization.
Q: What about culverts? Does the state inspect those?
A: Yes. We don’t inspect structures below 10 feet.
Q: To save money, can towns install pre-engineered bridges?
A: Pre-engineered structures are an acceptable [solution] for the smaller structures. We have done them and installed them ourselves. They are very good, low-cost options. One of those prefabricating companies delivers the bridge that you basically install in components.
Q: Why do cities and towns struggle to maintain their bridges?
A: It’s money.
Q: So what should communities do?
A: Preventative maintenance. Make sure the bridge is clean ... to keep the beams from corroding. Do some concrete repair. These little things don’t cost that much but they will extend the life of the bridge.
Q: Are you aware of any new federal money for bridges, since President Donald Trump spoke of his infrastructure plan?
A: We’re operating under the current funding program.
Q: So without enough money to replace all the deficient bridges in the state, how will MassDOT keep up with aging spans?
A: We have to balance the needs of all our districts, and we try to do a little bit in each district. District bridge engineers communicate to me what their priorities are in terms of safety and condition.