Trip to Green to aid in bridge work

Progress in the bridge project so far has largely been, quite literally, laying the groundwork — building roads up the steep canyon to provide access to the worksite and cutting notches into the canyon walls for where bridge footings and columns will later be seated. With the notch-carving complete, Deputy Director of Engineering for DOT John Kahling explained to councilmembers that work had begun on the pilings that will serve as a base for the supporting columns of the bridge. 

The aid requested from the city comes into play once the pilings have been completed — estimated to be in February, though weather conditions may lead to a delay. In order to aid with the execution of the time-sensitive and critical phase of construction — the pouring of the footings that the bridge's support columns will be seated on — county transit officials have asked the city enact a special one-night Trip to Green program. 

"When work on the pilings is done, we'll have to pour footings on which the columns will rest," Kahling explained. "On the south side of the river, the Placerville side, we will pour a footing 59 feet by 62 feet by 9 feet deep. It'll take 120 concrete trucks to fill in."

With the horde of concrete trucks set to traverse Highway 50 over the course of one evening, even minor delays such as red lights at one of the city's three highway intersections could add up to trouble for the herculean construction effort.

"The pour has to go continuously," Kahling said to the council. "We considered a two-day pour, but a joint in the concrete would be a deal-breaker from a stress concentration perspective. We do not want a cold joint. With 120 trucks coming through Highway 50, even just a two-minute delay for each adds up to over a two-and-a-half-hour cumulative delay. That kind of delay multiplies real quickly with these three traffic signals in town. Enough of a delay, we could risk a cold joint."

The council unanimously approved the proposal, meaning the next step for organizers is receiving approval from Caltrans. Vice Mayor Jackie Neau expressed her appreciation that the planned time was shifted to later in the evening than the original plan, minimizing potential impacts to businesses.

"Now let's go get Caltrans on board," Mayor Michael Saragosa said after the vote had closed.

The Trip to Green proposed to aid the project would differ from prior ones in three key ways: it would run overnight, from 9 p.m. to 9 a.m.; right turns onto and out of Canal Street would be allowed; and the turnoff to Mosquito Road would be closed to traffic other than construction vehicles. Though prior runs of the Trip to Green project came at a cost to the city, the contractor on the Mosquito Bridge project is set to absorb all costs for setup and operation for this special occasion.