Thermal Stress Analysis of Lock Wall Dashields Locks, Ohio River

摘要

A recently developed thermal stress analysis procedure was used to study the effects of a variety of parameters on cracking in concrete overlays for the Dashields Locks, Ohio River, Pennsylvania. The objective of the research was to develop improved designs and construction procedures to substantially reduce or inhibit cracking n the concrete overlay sections. Thermal stress analyses included the effects of placement temperature, ambient temperature, thermal properties of overlay, shrinkage, creep, reinforcing steel, and restraint at the interface between the overlay and existing concrete. These analyses indicated that shrinkage was the predominant factor in overlay cracking for the particular mixture to be used on the project. It was recommended that shrinkage be reduced by adopting one or more of the following modifications: decreasing teh cement content of the mixture, decreasing the water-cement ratio of the mixture, using a larger maximum size aggregate, or limiting drying shrinkage by using wet-curing. It was also demonstrated that an effective bond breaker at the interface would eliminate cracking. Keywords: Locks waterways; Aging materials; Creep; Finite element method; Lock walls; Navigation locks; Overlays repair; Shrinkage. (edc)