LA-1 over I-49 bridge was built in 1989. The as-built bridge consists of four continuous, steel plate girder spans with a total bridge length of 403 ft. and 45 degrees skew.
SDR performed thorough document review, hands-on inspection, surveying, and detailed analysis. A topographic survey revealed that both abutments are experiencing excessive settlement and lateral movement, resulting in transverse shear and uplift forces on the bearings at both abutments; increased reactions at intermediate bents causing over-stress and excessive deformation of bearing pads; redistribution of loads to internal supports, exerting more force on the foundations of internal bents; and additional negative moment, causing high tensile stresses and significant cracking of the deck.
SDR presented three alternatives to rehabilitate the bridge. The selected alternative consisted of adding two end spans of 100 ft. each to reduce embankment height and utilizing wraparound Mechanically Stabilized Earth (MSE) walls. In addition, SDR provided construction support.