Thermal Stress Analyses of Mississippi River Lock and Dam 26(R).

Abstract : This report describes an investigation to analyze selected monoliths of Mississippi River Lock and Dam 26 (Replacement) (L&D 26(R) for thermal and construction induced stresses using three-dimensional (3-D) finite element methods (FEM). The St. Louis District recommended that one of several commercially available general purpose FEM codes be used to perform the analysis. The guidelines to accomplish the goals of the study were developed into evolutionary four-phase plan. The first phase was to evaluate and select a code from the recommended candidates best capable of modeling the problem. Evaluation criteria included the capability to simulate incremental construction, materials aging, time-stepping, inclusion of a comprehensive element library with capability to easily implement user-defined material models, the ability to model large numbers of reinforcing bars, and have efficient numerical solutions with flexible means for selecting time steps. The program was also required to be user-oriented, be well supported by the developer, and have a high potential for remaining at the state-of-the-art level. After evaluation, a review committee selected the ABAQUS program as the code best suited to solution of the problem. Results indicated that concrete stresses and the distribution of pile loads beneath the monoliths are significantly affected by the assumptions made in the analysis such as single-stage gravity turn-on versus staged, incremental construction with temperature effects, and also aging, creep, and shrinkage.