Weigh-In Motion System Added To Damaged Twin Span

Staff | September 28, 2010

Slidell, La.— A new weigh-in-motion (WIM) system has been added to keep overweight vehicles off the hurricane-damaged Interstate 10 Twin Span Bridge. As a result, inspection crews will reduce the number of times per week westbound lanes close for maintenance.

Between Dec. 3 and Jan. 16, the system detected an average of 52 overweight trucks per day. Overweight trucks, which cause damage to the prefabricated deck panels that replaced portions of the westbound span, were rerouted away from the Twin Span Bridge. Because fewer overweight trucks are crossing the bridge since the WIM opened, inspectors report a 20-percent decrease in the number of broken bolts that hold the deck panels to the bridge supports and are reducing lane closures from four times a week to three.

The entire bridge is inspected daily, with the westbound span shut down four times per week for repairs. The westbound span has a 70,000-pound weight limit for tractor-trailer combinations. Weight-limit signs are posted at six miles and three miles before the WIM.