Stay Cables of the Luling Bridge are to be Replaced

摘要

This paper summarizes an ongoing 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 Luling Bridge. Recent inspections have found a variety of critical damages to the protective sheathing and exposure of the main tension elements of the stay cables with an increasing rate of degradation. Prior to attempting repairs, a life-cycle-cost analysis was performed to assist the decision making for maintenance and management. The results indicated that when all costs are considered and both agency and users' costs are included, strategies involving repair or replacement competed closely while the cost of "doing nothing" was significantly higher. LADOTD decided to replace all cables. The cable replacement design, the first occasion of its kind in North America, will be heavily influenced by the geometric restrictions and cost. The replacement cables are designed for a 75-year design life incorporating improved corrosion protection and vibration control. The construction sequence will incorporate temporary cables and analysis of construction effects to limit stress variations on the bridge and cables. The bridge is a critical regional link and a hurricane evacuation route, and traffic interruptions shall be designed to be as unobtrusive to the public and commerce as practical.