Upgrading and maintenance programs were proposed at a power generating plant in Indiana. To perform construction activities associated with the proposed upgrading and maintenance, a LR11350 crawler crane with a dead load of 1, 500 ton was required in the vicinity of existing plant structures. The contact pressure from the crane tracks for the heaviest lift, maximum reach and angle (worst loading condition) were estimated by the rigging engineer to be on the order of 84 psi. Several concerns were raised regarding the total and differential settlements while the crane is in operation and the induced stresses on existing underground utilities due to crane loads. Three-dimensional finite element simulations were conducted using hardening soil model for the subsurface soils and elastic model for the other structural elements (underground utilities and crane mats) to optimize the configuration of the proposed crane foundation. It was found 1-foot thick engineered steel mats underlain by a 1.5-foot thick crushed stone pad will provide enough support to the crane. It will also control the settlement to the allowable limit and maintain the stresses in the underground utilities within tolerance.
Subjects: Crane Pad, Underground Utilities, Finite Element Analysis, Local Buckling, Ovality
Author: Yao Zhang, Ph.D., P.E. and Yazen Khasawneh, Ph.D., P.E.