This 1.4-million-bushel grain elevator distribution and storage facility experienced structural failure and collapse during a 60+mph wind storm. Originally built with five grain bins and a single grain elevator tower, more grain bins, grain elevator towers, and an elevated horizontal conveyor system with support towers were added to increase capacity and move the grain to and from trucks and trains and between grain bins and the dryer. The collapse resulted in complete loss of the elevator and conveyor systems and damage to the grain bins and dryer.
RRJ was retained by legal counsel years later to evaluate the credibility of the opinion of other expert consultants that the collapse had been caused by weld defects in the newest grain elevator tower. RRJ reviewed project documents, examined the condition of tower members and connections retained by the owner’s consultant, and analyzed the as-designed and as-built load cases for the elevator tower in question, the conveyor system, and two adjacent towers.
RRJ found that the towers’ existing conditions differed substantially from the original design. The newest, freestanding grain elevator tower had been erected with unplanned connections to an existing horizontal conveyor. RRJ’s analysis of the relative stiffness of the new tower, adjacent conveyor support towers, and elevated conveyor structure concluded that the newer tower’s load resistance was more than twice the adjacent towers. The new tower’s connection to the conveyor and its relatively high stiffness increased the loads the structure would need to resist during a wind storm. These loads had not been considered by the other consultants. The project document review and examination of the retained tower base connection components demonstrated that some of the older towers exhibited severe pre-collapse member and connection distress. Corrosion failed the welded connections at one tower’s base, and ground settlement had caused rotation of the concrete base of another. These conditions, which affected the stability of the older towers, had not been considered. RRJ’s findings resulted in a favorable outcome for the client.
