By Michael Raffety
Syblon Reid Construction is two-thirds complete with the concrete structure for the Camp 2 Bridge project. After pouring 50 yards of concrete June 4 SRC will have one section of retaining wall to complete.
The replacement contractor has even completed some of the forms for the cantilevered part of the bridge.
Project manager from the El Dorado Irrigation Districts js Jake Eymann, who said the bridge project is on schedule for completion in September.
This has been a long project for Eymann. Not only has he developed the design of this project over eight years, but now he is working on follow-up documentation regarding the legal case involved in firing the first contractor.
Excavating Engineers out of San Diego began work on the Camp 2 Bridge, Aug. 1, 2014. That original contractor completed most of the rock scaling, boulder removal and created some ledges for the retaining wall and abutments.
“In the interest of successfully completing the project,” EID ended the San Diego firm’s work on the site Dec. 31, 2014, and they were paid $400,000 on what was originally supposed to be a $1.498 million contract.
Syblon Reid, which has done a number of flume construction contracts for EID, began work in March after the site had been secured in January. The contracted amount is $2.1 million.
Syblon Reid also had to cut off the rebar installed by the prior contractor since it was out of alignment. SRC also had to shave off more rock, this time using a hydraulic rock splitter. Syblon Reid also recut portions of the buttresses and retaining wall footings.
To accomplish the work the new contractor built scaffolding anchored into the rock. The scaffolding provides a safe work platform and location for tools and lumber. It also provides a place for Eymann and on-site EID inspector Martin Bross to get a close-up look at the work. Bross is there every day the contractor is working and senior engineer Eymann checks the progress weekly.
Unfortunately, the first contractor had damaged the north abutment of stacked rock when they dropped a number of big boulders on it. “Just crushed it,” is how Eymann described it. Now that abutment has been cleaned down to the bedrock as it originally appeared after the Chinese had blasted the rock when the canal and flumes were built between 1874 and 1876 at a cost of $650,000 ($25,000 per mile). It took 1,500 men — mostly Chinese and Italians — two and a half years to complete the canal.
Camp 2 Bridge and the road it connects to the Camp 2 House and Plum Creek Siphon, together make up the original the canal route. The overall photo of the Bridge was taken from the remains of the canal base across the Plum Creek canyon. PG&E bypassed this section of the canal by building a reverse siphon 1,444 feet from Camp 2, across Plum Creek to the other side of the canyon. The siphon has a diameter that varies from 60 to 72 inches, with the narrow section at the bottom to increase water velocity so that debris won’t collect at the bottom, according to Eymann.
The crewman at the Camp 2 House is in charge of keeping the trash rack clean to ensure that the siphon doesn’t get plugged up and to keep ice out of the siphon.
The Camp 2 crewman tends just under a mile of flume and canal and two spillways as far back as the Mill Creek to Bull Creek tunnel. In the winter sometimes snow conditions mean food supplies have to be brought in on a snow cat.
Along with installing the siphon, PG&E built the Camp 2 Bridge as a wood trestle-like structure in place of what had been a flume. This wood bridge eventually became rotten and rickety. In this decade EID stopped allowing anything heavier than an all-terrain vehicle to use it. Helicopters brought in propane tanks that run some of the remote spillways. That is a $13,000 delivery expense.
PG&E had bought the canal and its hydroelectric system from Western States Electric Co. in 1928. Expanding the canal capacity is part of the reason PG&E built two siphons and Esmeralda Tunnel in 1930.
EID acquired the 22 miles of canal, flumes and tunnels, four alpine reservoirs, Forebay Reservoir and a 21-megawatt powerhouse in 1999. In this second year of drought the system has added more than 7,000 acre-feet of water to Jenkinson Lake at Sly Park, which is the district’s principle water supply.
Completing the bridge project will also mean EID can use a truck instead of a helicopter deliver lumber to rebuild Flume 30.
The bridge structure is 175 long and 27 feet high and is more accurately termed a viaduct. Once the retaining wall is completed PVC pipes left in the anchor abutments will be uncapped and used to drill down 10 feet into bedrock and then anchor bolts will be cemented into place. That will totally anchor the retaining wall back into bedrock. Then gravel and road base will fill in behind he retaining wall and guardrails installed on the cantilever.
After the whole structure is completed then the rocks above it will be tied back with 23 anchor bolts. Two huge boulders below and above south bridge abutment have already been tied back with anchor bolts.
The structure is built to last 100 years.