Challenge
The creek valley featured a wide flood plain that required spanning in addition to the creek. Scour was a concern for foundations within the flood plain.
Solution
Our team designed a skewed three-span continuous (40m – 40m – 40m) two-lane bridge with sidewalks and bike lanes to span the valley. Limiting the spans to 40m allowed for the use of prestressed, precast concrete girders (CPCI 2300), which were cheaper and more readily available than competing steel I-girders. The total span precluded the ability to use integral abutments, so semi-integral abutments were chosen to eliminate abutment expansion joints. The cleat connections between the wingwalls and abutments were specially designed to transfer the bending moments from the wingwalls down into the abutment footings via torsion because the semi-integral deck ends limited the connection strength between the wingwalls and abutment stems. The abutments were piled and the piers were founded on deep spread footings to address scour concerns.