Operating and Maintaining Median High Tension Cable Barrier on Highway 2 in Alberta

Alberta Transportation has been a leader in the application of High Tension Cable Barrier (HTCB) as a median barrier. In 2010, construction of 133 km of HTCB in the median of Highway 2 was completed from North of Airdrie to Red Deer and near Leduc. The design of this HTCB was complex due to the variety of median conditions when considering variables such as median width, sideslopes, and existing hardware in the median. Recent inquiries with HTCB suppliers indicate that this project remains the largest single HTCB installation in North America to date. Previous papers in TAC proceedings by staff of EBA, A tetra Tech Company, have discussed the design, construction and safety performance of this HTCB project. This paper will present a comprehensive discussion of the various maintenance and operational issues and considerations for this HTCB installation. The maintenance and operations of the HTCB has included repairs following hits (replacement of posts and attachments, cable sections, turnbuckles, etc.), regular maintenance, and changes to mowing and snow clearing practices. Although repairs to the HTCB can be completed faster than steel beam barriers, traffic accommodation to ensure the safety of workers and the traveling public is of paramount concern on Highway 2. Another issue which has resulted in the need for repairs of the HTCB is the cutting of the cable by first responders to free vehicles caught in the HTCB. Cutting of the cable can be hazardous due to the high tension in the system and results in a need to splice the cable or replace a significant length of cable at a high cost relative to alternative methods of releasing tension in the system. To reduce the frequency of this occurrence and to minimize risk to first responders (firemen, police, and tow-truck operators), EBA provided training sessions in Leduc, Red Deer and Calgary. The content of, participation in and results of this training program will be discussed. Following the first year of operations a warranty inspection was completed and the observations and repair requirements are presented. Lessons learned from the review of these topics will be of use to road agencies that are proceeding with the use of this flexible barrier system that has proven to be effective in reducing the severity of cross median collisions in Alberta and elsewhere.