A series of winter storms last January and February flooded low-lying areas along a section of Highway 37 between Highway 101 and Atherton, prompting state highway officials to commission emergency repairs using a fast design and reconstruction process to stabilize and raise the roadbed as quickly as possible so traffic could resume. Meanwhile, pumps were used in an effort to drain the water. Detours caused motorists to endure longer drive times.
In total, this highway segment was closed 12 days from January 11 to the 23, and again for 16 days starting on February 8. The second closure involved 1,500 feet in both highway directions. The road remained closed for seven days while road crews worked around the clock to raise it. Traffic was restricted to a single direction for an additional five days.
Caltrans hired Santa Rosa-based Ghilotti Construction Company (GCC) on February 10 to raise the roadbed and to provide coordination of other related repairs. The emergency contract allowed GCC to work 24 hours a day while coordinating its efforts with subcontractors, vendors and the Caltrans team.
Ghilotti served as prime contractor responsible for managing grading, drainage, and the installation of three drainage culverts among other tasks. Some 2,516 cubic feet of lightweight fill dirt and 8,238 tons of paving were required as well as the implementation of erosion controls at the site.
The project consisted of raising the pavement elevations both east and west bound above flood levels. Some 1,400 linear feet of sheet piles formed a wall and concrete barrier installed on the eastbound side, median and cross-drainage systems was built along with headwalls with slide “tide” gates. Existing levees were reinforced, the median was graded and triple metal beam guardrails were reinstalled. When repairs were finished, the highway was restriped.
“Ghilotti Construction Company has a long track record when it comes to being able to work at a fast pace and successfully deliver emergency contracts,” said Robert Haus, Caltrans public information bureau chief for District 4. “This was a short-term remedy as discussions continue with our local partners on a more permanent solution.”