By Mark A. Diaz
The Avila Beach Drive Bridge that crosses over Avila Beach and the San Luis Obispo Creek inlet requires repair work to bring the structure up to modern standards that include a seismic retrofit to guard against earthquakes. The bridge, constructed in 1967, provides the only public access to Port San Luis and the Diablo Canyon Nuclear Power Plant.
A 2010 PG&E study that focused on evacuation routes for Diablo raised concerns that the bridge could collapse if struck by an earthquake.
“If we had a sizeable earthquake, there is always a danger of collapsing,” said Matt Reinhart, SLO Public Works project manager,” and that’s why we’re doing a retrofit.”
The San Luis Obispo Public Works Department contracted Souza Construction, Inc. for $1,757,317 to perform the work that is set to begin in mid-July with a January 2019 goal for completion.
The retrofit includes cable restrainers and strengthening of bridge connections, a new approach slab, stabilization at the east end of the bridge and removal and replacement of existing asphalt on the bridge surface with a new polyester concrete deck overlay. Reinhart said that the polyester concrete resurfacing is accomplished quicker than other forms of overlays and also hosts additional benefits such as higher tensile strength and flexibility.
“It cures faster than regular asphalt and tougher than regular asphalt,” said Reinhart. “For instance, when they remove the old asphalt and put polyester in, they can put traffic on it almost right away.”
The project also entails the removal and replacement of unsound concrete on the bridge supports. Some of the pier walls that support the structure rest in the creek and are subject to erosion and scouring from the flowing water. Therefore, the retrofit involves replacing the pier wall jacket, a rebar and concrete sleeve that surrounds the supports.
Public Works said that work on the above roadway portion of the bridge would not commence until after Labor Day (Monday, Sept. 3) and that no action will be done on weekends or holidays. Work in the roadway will occur only during off-peak hours with single-lane closures. Bicycle and pedestrian traffic will be maintained at all times during construction, though automobile drives may experience a maximum delay of 10-minutes.
The bridge experiences a high rate of vehicles for a non-through road with more than 200,000 crossings in the eastbound lane alone in July 2017, which equates to over 6,600 a day for a single lane with peak volumes reaching over 870 vehicle crossing in a single hour.
Additional work is being done with bridge by the Chevron Environmental Management Company. The project involves the removal of five abandoned petroleum pipelines that rest under the bridge. The removal project is estimated to be concluded by the middle of August 2018.