Luling Bridge Stay Cable Replacement

This paper summarizes an evaluation and cable replacement design program initiated by the Louisiana Department of Transportation and Development (LADOTD) to address deficiencies reported for the stay cables of the Hale Boggs Bridge, also known as the Luling Bridge, in Luling, Louisiana. Recent inspections of this bridge have found a variety of critical damages to the protective sheathing and exposure of the main tension elements of the stay cables. The rate of degradation is increasing and a timely action is necessary. A life-cycle-cost analysis was performed to assist the decision making for bridge maintenance and management. The results indicated that when all costs are added and both agency and users’ costs are included, strategies involving repair or replacement competed closely while the cost for the Base Case was significantly higher. Based on the results of this investigation, LADOTD decided to replace all cables. The design of the complete 72-cable array replacement is believed to be the first occasion on which this process was attempted in North America. It is heavily influenced by the geometric restrictions of the existing anchorage locations, including erection restrictions and estimated costs. The replacement cables are designed for a 75-year design life incorporating the latest advancements in corrosion protection and vibration control. The new parallel-strand cable system allows individual strand installation, tensioning, inspection and replacement. Due to the suspected poor condition of the existing cables, the construction sequence incorporates temporary cables and detailed analysis of construction.