Over the years, a number of accidents have sent everything from cars to a milk tanker truck into sound walls along the Louise Avenue corridor.
Rarely did pieces of the masonry wall fly more than 10 or so feet.
Recently a car made a glancing blow on a sound wall that was put in place as part of the Del Webb at Woodbridge housing development north of Lathrop Road on Union Road.
The masonry wall virtually exploded as pieces of blocks was sent airborne for nearly 115 feet with debris heavily scattered.
The aftermath of the crash stunned city staff.
Had a house been a typical 20 feet away from the wall it would have sustained damage. There were only vacant building lots adjacent to the wall that was hit on Union Road. And given the fact bedrooms are typically located to the rear of homes, the result of the account could have been dramatically different as Community Development Director Frederic Clark noted in memo to the City Council.
The large debris field was because the wall was pre-stressed masonry wall that stores energy causing the wall to explode when it is ruptured.
Manteca sound walls historically have been construct-in-place, grout-filled, reinforced masonry walls.
That’s why the City Council during Tuesday’s 7 p.m. meeting at the Civic Center, 1001 W. Center, is being asked to adopt a policy that prohibits pre-stressed or post-tensioned masonry walls adjacent to roadways where they can be struck by vehicles. Instead masonry walls that are solid grout filled would be required instead.
The pre-stressed walls would be allowed along pedestrian or bicycle path in areas that aren’t adjacent to roadways.