Out with the old.
In with the new.
That was the project theme in Wethersfield, CT, recently when Empire Pavement teamed up with United Concrete to build a new sewer pump station. The $2.9-million project began in early spring 2007 and is now complete.
According to Empire Pavement Vice President Earl Tucker III, the project included the "excavating and shoring of a 40-foot-deep hole in order to install this mammoth concrete pump station, wet well and valve chamber as well as a building on top.
"The hole was 40-foot by 40-foot in diameter and 40-feet deep," Tucker said. "We used beams and wood lagging shoring that would stay in place. The shoring was 40 feet by 40 feet. On the bottom of the hole was a large concrete slab 2 feet thick that created an anti-flotation slab. We had a large 300-ton truck crane that lifted 15 to 16 pieces of pre-cast concrete that we lowered onto the slab, then bolted them down. They were all different weights, but the largest was 55 tons."
Tucker said the hole was dug with a long reach Volvo 220 excavator.
"We also had a Volvo 55 mini-excavator in the hole for the last 10 feet to loosen up the dirt for the bigger excavator to grab," Tucker said. "We encountered a little bit of water but we ran three 3-inch prosser pumps."
Tucker said the crew showed up with trailer trucks and set the structure in one day.
"We spent a week backfilling the outside of the station while United Concrete tied the plumbing and electrical together," Tucker said. "Then we put a brick veneer on the outside of the pre-cast building that sits on top of the wet well and valve chamber. It looks like a simple square brick building."
Tucker pointed out that the new pump station took the place of the older pump station that was outdated.
"This one line takes all of the sewerage out of most of the Wethersfield area and moves it through a 24-inch pipe. The old pump station could not handle the job, so the new station bypassed the old with 12-inch sewer bypass pumps. There was no way to stop the flow of sewerage. We had to keep it flowing as we were working."
The sewerage from the new station flows into a sewage treatment facility located next door.
The scope of the project included construction of a new pre-cast wet pit/dry wastewater pumping station to replace an existing pumping station.
The wastewater pump station work included the demolition of the existing pump station including structures, mechanical equipment, HVAC equipment, plumbing equipment, instrumentation and control equipment, electrical equipment and yard features. Station work also included construction of a new pre-cast wet pit/dry pit wastewater pump station including civil, architectural, structural, mechanical, HVAC, instrumentation and electrical improvements; construction of a new force main; sewer pipe and stormwater pipe of various sizes; manholes; pipe connections to existing sewer and stormwater systems; paving; removal and disposal of hazardous material; construction of a yard hydrant; miscellaneous site and yard piping work; and maintenance of operations during construction.
The work also included coordination with electric company for relocation of power pole guide wire, site restoration, and miscellaneous work and cleanup to complete the work as detailed on the drawings.
Tucker said during the project there were approximately 12 laborers per day doing the work.
"The project went well," Tucker said. "The interesting part was that United Concrete first assembled the station in their yard and then ran it to test it. Then they had to disassemble it and haul it to the site and put it back together again. They didn't want to get out there and find out that there was a problem. When bypassing, it could be a big deal and they wanted to make sure it worked."
Dave Topa from United Concrete said the company is able to test the station at the United Concrete facility prior to shipping.
"We manufacture all of our precast pump stations and buildings in our facility and in a controlled environment," Topa said. "This allows us to build the stations with no weather issues and allows us for tighter quality control. United can pre-test the stations at our facility if requested by the engineer or the owner. That includes checking all the electrical and mechanical connections prior to shipment. This allows us to have better control over the fabrication of the stations at our plant. This one took seven months from start to finish. Once the station was complete and tested, we disassembled it and shipped it to the site on 40-foot trailers."
After the excavation was complete, United Concrete worked closely with Empire Paving to deliver and assist in the installation on the station.
Topa said the estimated value of the package pump station is about $1.5 million.
"There was a team of seven that worked on the manufacturing of this station," Topa said. "There were 16 separate sections which were used to build this station. The heaviest section weighed 55 tons."