Many people have asked about the use of bridge jacks on the Interstate 10 Twin Span Bridge between New Orleans and Slidell. The public obviously is apprehensive about bridge safety in light of the Minnesota bridge collapse, and DOTD wants to make sure everyone knows the status of the bridge.
The jacks are in locations where the existing bearings sustained between 25% and 40% damage. These specially designed jacks provide additional support to the damaged bearings. Although the existing bearings still carry most of the load, the jacks can support as much as 25 tons each, providing a redundant measure of support.
Also, the materials beneath the jacks are not pieces of lumber, as one internet publication speculated. They are bearing pads, a neoprene pad that is commonly used as an extra measure of support between a girder and cap.
The Federal Highway Administration has approved of this jack technique and has paid 100 percent of the cost of the repairs. This technique also has been used on other bridges with great success. The Twin Span Bridge jack locations are monitored very closely, and the system is working well. Structural engineers report no degradation of the beam seats since the bridge was re-opened, which proves the jacks are performing as intended.
The Twin Span Bridge is safe, but keeping it safe requires daily inspections and frequent maintenance. DOTD appreciates the public’s patience as we continue to maintain our aggressive inspection schedule. We understand the periodic lane closures are inconvenient to drivers, but the closures are necessary to ensure the safety of our citizens.