Field Trials for Cost-Effective Strengthening of SC Load Posted Bridges

South Carolina’s transportation infrastructure includes many bridges that are load posted due to structural considerations (e.g., outdated design loads, members whose capacity is difficult to assess, etc.), resulting in substantial costs to the public. As a result of the statewide load rating efforts, the number of load posted structures is expected to rise significantly. The rising number of posted bridges will have an adverse effect on both travel and commerce in South Carolina. Bridge strengthening techniques need to be explored to mitigate these effects. The goal of this research is to reduce the number and severity of bridge postings in South Carolina. The objectives are to: a) identify, customize, and implement strengthening strategies in the field that are potentially effective for South Carolina; b) evaluate the short and longer term effectiveness of these strategies, including refinements to analysis methods which may be sufficient to remove some postings; and c) potentially test and monitor SCDOT provided materials and/or specimens. Anticipated results include a review of best practices from other states, surveys conducted with SCDOT engineers, and a summary of strengthening methods, effectiveness, and cost. Payoff potential will be assessed through cost-benefit analysis of field implemented strategies. Load-posted bridges are an impediment to system efficiency and development and implementation of cost-effective strengthening strategies to remove postings has very high payoff potential. Successful implementation of this research will be achieved by the development of: a) standard design drawings that can be used to develop bridge strengthening projects; b) standard specifications to accompany each project; c) guidelines for determining the applicability of each technique; and d) guidelines for means and methods to be used for each set of standard drawings.