MODESTO — The Carpenter Road bridge, which serves as a main link between Modesto and Patterson, will remain closed until late Friday after roughly 1.3 million gallons of water from a broken water line washed out the soil under one end of the span.
A security guard spotted the leak about 6 a.m. Tuesday on the northeast side of the bridge, which crosses the Tuolumne River in west Modesto. The guard was hired by the construction company that is upgrading the 53-year-old bridge.
The water from the 16-inch water line washed out the soil under several feet of Carpenter Road's northbound lane by the north side of the bridge. The water also washed out soil along a nearby abutment crews built as part of the upgrade.
City officials met with the contractor Wednesday to discuss how to fix the problem and reopen the busy bridge. Some 19,035 cars and trucks cross the bridge on a typical day. Modesto officials said the bridge should reopen by late Friday afternoon.
"We are doing everything we can to reasonably expedite the work," said Gregg Halladay, Modesto's deputy director of utility planning and projects. "We've given the contractors direction to work late if it helps."
The 628-foot-long bridge will remain open to walkers and bicyclists as long as it is safe to do so.
City officials suspect a joint that connects two sections of the water line on the bridge's north side failed, causing the sections of pipe to come apart. The water line runs the length of the bridge and eventually feeds into four storage tanks that supply water to homes and businesses south of the Tuolumne River.
Halladay said none of those customers went without water. At worst, he said, they experienced low water pressure.
City officials are investigating what caused the joint to fail. Halladay said it's been about six months since that section of the water line had been worked on. As part of the bridge upgrade, the contractor is replacing the 16-inch water line, which runs along the east side the bridge, with a 20-inch water line inside the bridge.
Halladay said the repairs include removing the muddy soil from the abutment and under the road. Workers then will fill the abutment with a loose concrete that will fill every crack and crevice and then with compacted dirt. Workers will fill the hole under Carpenter Road with compacted dirt.
"We are going to put more dirt in the hole than came out of it," Halladay said. "That makes it more stable to support the loads above it."
The bridge is just one of several spots where drivers can cross the Tuolumne River and is an important connector between Modesto and western Stanislaus County.
"We cross it a couple times a week," said Patterson resident Shellie Scott, 53, who had her mother, Barbara Scott, in her pickup as the two were stopped in front of the bridge's south side Wednesday.
They were on their way to Modesto's Vintage Faire Mall and planned to detour through Ceres to reach their destination.
"I want it to be safe," Scott said about the bridge. "If it's not safe, then you don't go."
Until the bridge reopens, drivers can take Highway 99 or Crows Landing Road and the Seventh Street bridge to the east, or Paradise, Shiloh and Grayson roads to the west.
Modesto is spending about $10.8 million in grant money to upgrade the Carpenter Road bridge, which opened in 1960. The contractor, Benicia-based Flatiron West, started work last year.
The project includes making the bridge better able to withstand an earthquake as well as widening it from 34 feet to 69 feet. The bridge will remain two lanes, but it will have 12-foot wide walkways on each side. Concrete barriers will separate walkers and bicyclists from traffic.
Halladay said Tuesday's incident may cause minor delays to the bridge work, which is expected to be done in June. He said the contractor will have to redo some work, such as removing the water, mud and sediment from pilings that will support the bridge's new section.
Bee staff writer Kevin Valine can be reached at firstname.lastname@example.org or (209) 578-2316.