Kanan Road T1, T2, and T3 Tunnels and Malibu Canyon Road Tunnel Lining Project

Narrative Description Of Your Entry The Kanan Road T1, T2, and T3 Tunnels and Malibu Canyon Road Tunnel Lining Project consists of seven tunnels located in the unincorporated County area near Malibu. The seven tunnels are identified as follows: • Malibu Canyon Road Tunnel, tunnel length = 560 feet • Kanan Road Tunnels •Tunnel ‐T1 Northbound, tunnel length = 515 feet •Tunnel ‐T1 Southbound, tunnel length = 515 feet •Tunnel ‐T2 Northbound, tunnel length = 880 feet •Tunnel ‐T2 Southbound, tunnel length = 880 feet •Tunnel ‐T3 Northbound, tunnel length = 320 feet • Tunnel -T3 Southbound, tunnel length = 390 feet The tunnels were constructed between 1952 and 1983 with a combination of steel and gunited linings and provide a vital link between the City of Malibu and the City of Agoura Hills. The Average Daily Traffic (ADT) for the Malibu Tunnel, Kanan Road T1, T2 & T3 are 20,000, 11,000, 3,000 and 3,000 respectively. This project which represents a collaborative effort between multiple agencies, included safety and preservation enhancements, collaboration and partnerships, and sustainable design features. Vehicular Safety and Preservation Enhancements Based on inspection and maintenance records, the existing gunited tunnel lining showed signs of deterioration such as spalling, delamination, and water seepage with patches of efflorescence. In the past, spalled concrete had periodically been removed from the road surface in the tunnels. Visible cracks, seepage through the gunite, and paint flaking and section loss of the existing steel lining warranted rehabilitation of these tunnels. Although no injury or fatality due to falling of the spalled concrete had been documented on the tunnel, loose and debonded material posed a potential safety hazard that needed to be addressed. To mitigate the safety risk, the major scope of work for the project was to cover the existing gunited lining with a new steel lining, and apply new paint to preserve the existing steel linings. Furthermore, a combination of an impermeable membrane and PVC drain pipes were also installed behind the new steel lining to direct seepage water from the crown of the tunnel to the sides where it can be intercepted. This project will improve public safety and preserve the performance of the tunnels. Collaboration and Partnerships The project required full and partial closure of the tunnels during construction and a tremendous amount of coordination with the County Fire Department took place during the design phase to ensure that emergency response times and fire truck access were not compromised. Public outreach with local residents in the unincorporated County Area, City of Malibu, and City of Agoura Hills were also carried out before the project was advertised. Advanced notification and detour signage were posted to divert traffic to other adjacent routes, such as Latigo Canyon Road, Las Flores Canyon Road, and Topanga Canyon Boulevard. Sustainable Design Features At the Kanan Road T1 Tunnel and Malibu Canyon Road Tunnel which are both located within the Coastal Zone Area, a bioswale system was incorporated into the project and is designed to remove pollutant from pavement runoff before discharging it into the existing storm drain system. The bioswale system consists of a sloped area filled with vegetation and gravel rocks on base materials which will trap pollutants from roadway runoff before releasing it to the watershed. Construction of the Kanan Road T2 and T3 Tunnels were completed in 2014 and construction of the Kanan Road T1 and Malibu Canyon Road Tunnel is scheduled to be completed in summer of 2015. This project has improved the quality of the local roadway system within Los Angeles County. It has enhanced safety, promoted collaboration among local agencies, and provided sustainable design features. Supporting Documentation 1) Location Map and Pre- and post-construction photos (see attached)