Source: https://www.constructionexec.com/, October 7, 2020
By: Mitch Cohen, RT ECP

A temporary retaining wall was being constructed for on a new bridge in downtown Atlanta to retain excavated soil as a footing for the bridge pier. The plans specified the placement of retaining wall support beams one-third and two-thirds below the excavation. Everything was going well and ahead of schedule, so the young, inexperienced construction manager agreed to the contractor’s request for placing the two layers of support at the two-thirds point the following morning.

Unfortunately, a torrential storm the night before caused the water behind the unsupported retaining wall to shift its top 18-inches forward. Even worse, the telltale signs of soil failure upslope from the top of the wall (a C-shaped curved crack in the retained soil) dictated the need for an immediate remediation to save the retaining wall. The construction manager’s error in judgment contributed to the project’s shutdown by the job superintendent, causing a one-and-one-half-day delay and frantic scramble to place two layers of supports and a second row of sheet piles behind the bowed wall. Read more.