Design of Steel Splice Repair for Decaying Timber Piles on Oklahoma County Bridges

Abstract

The purpose of this project was to identify recurring structural issues on off-system bridges and design an inexpensive, simple repair to resolve the problem. After communicating with multiple sources, it was disclosed that an existing repair had been installed in the past to solve issues regarding decaying timber piles on older timber bridges. This repair had not been tested in the field, nor did it have a standard design. The repair can be described as a steel splice because it involves removing a length of decayed timber pile (from the pile cap to the ground) from under a bridge, and replacing that section with a steel member, either an H-Pile or a pipe. The steel section is then connected to the existing timber pile below grade by way of a fabricated sleeve, made up of a section of pipe that slides over the timber pile and a steel plate that is welded on top of the pipe. Field testing of this repair was conducted to determine the performance of the repair. Based on the field testing results, this repair is an effective way to provide a load path from a pile cap to a foundation. The installation is simple, inexpensive, and can be completed in less than eight hours. To standardize the design of the repair and ensure a conservative capacity, design tables were created to help choose the dimensions of steel that need to be used. These sizes correspond with pipes and H-Piles that county governments typically have inexpensive access to. Included with the design tables are all design details and installation procedures.