New Support for Pin-Hanger Bridges

by Scott Christie, Proj. Engr.; Pennsylvania DOT, Bureau of Design, Bridge Design Quality Control Division, Harrisburg, PA,
John M. Kulicki, (F.ASCE), Consultant; Modjeski and Masters, Harrisburg, PA,

Serial Information: Civil Engineering—ASCE, 1991, Vol. 61, Issue 2, Pg. 62-64

Document Type: Feature article


To promote safety of their bridges, many state highway departments are considering ways to add auxiliary support to existing pin-hanger bridges. The Pennsylvania DOT and its open-end consultant have produced detailed plans for such retrofits on 21 state-owned spans. They coordinated new construction with planned maintenance and avoided major changes in the bridge profiles. Eliminating the pin-hanger connection, the best solution, was done on two bridges. On the rest, catcher type systems are installed under the girders or under the floor beams. It was not feasible to produce one design for all locations, so each is a unique design. But because the space between the catcher beam and existing structure would amplify the dynamic load during even a very small drop, a shock absorbing neoprene pad was added in this space. The specifications call for A633 grade E and A537 (60 ksi yield) steels for welded members, with stainless steel hanger rods. Most contractors bidding on these projects seem to agree that anything less would compromise the level of safety.

Subject Headings: Highway bridges | Dynamic loads | Bridges | Safety | Existing buildings | Infrastructure construction | Beams | Bridge design | Pennsylvania | United States

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