Have you heard any loud, sharp noises in the Anderson Student Center recently and wondered what caused the loud “bangs”?

Elizabeth Fischer, a project engineer for Opus Architects & Engineers, one of the firms that designed the ASC, explains that this sound is caused by “bolt bang,” a common phenomenon in steel buildings with single-plate, bolted connections. Bolt bang happens when the bolts in a single connection slip into full bearing, involving movement of less than one-sixteenth of an inch. The energy released causes a loud “bang” noise.

Fischer recently conducted an inspection of the building and reassured that “the structure will safely support the intended design loads and is in conformance with good engineering practices.”

The phenomenon is common in steel buildings and typically occurs during the first one to two years after the building is fully occupied. Bolt bang typically happens when live load is applied (a.k.a. when people begin to occupy the building) and when temperature changes occur, which, in turn, cause thermal expansion or contraction. Once a connection experiences bolt bang, it will not happen with that connection again.

So the next time you are in the ASC and hear a loud bang, rest assured and think to yourself “Oh yeah, it’s only bolt bang!”