39-Meter Boom On Barge-Mounted Pedestal Hard at Work on Galveston Causeway 2005
General contractor Traylor Bros., Inc., Evansville, IN has been on the IH-45 - Galveston Causeway Project since October of 2003. The contractor invests in their own pumping equipment to meet the placing requirements for nearly every contract. On the Galveston site, Traylor utilizes two trailer-mounted concrete pumps to place an estimated 225,000 cubic yards of concrete into two new bridges over the Galveston Bay. In January 2004, the contractor also invested in a Schwing KVM 39 boom to place an estimated 133,000 cubic yards of the project’s total concrete. Currently two weeks ahead of schedule, Traylor is enjoying the scheduling and production advantages of owning the right pumping equipment.
Galveston, TX is a popular island located in the Gulf of Mexico 50 miles southeast of Houston. The island is connected to the mainland only by the 40-year-old existing causeway, a two-bridge structure housing three lanes of southbound traffic and three lanes of northbound traffic. The Galveston Causeway Project involves the construction of two new 74-foot wide bridges running a mile and a half over Galveston Bay. The new causeway will be five feet higher and offer one additional traffic lane and shoulder lane for both the northbound and southbound bridges. According to the Texas Department of Transportation, the new Causeway will reduce traffic congestion and improve evacuation in the event of a hurricane. Besides bringing state-of-the-art pumping equipment to the site, Traylor also equips their crews with 27 barges and 15 cranes, all of which exceed 100-ton capacity.
Traylor Bros. and ready-mix supplier Dorsett Bros. Concrete Supply, Inc., Pasadena, TX, began the project on the south end of the Bay by erecting two temporary steel trestles, or a temporary steel bridge, for crane, personnel and material access. The crane trestle was constructed with T-roads to allow cranes and other equipment to get close enough to pour the drilled shafts for the new northbound bridge. The material trestle is equipped with tracks to enable rail cars and a locomotive to transport materials to the site’s work areas. For the first 2000 feet of the northbound bridge substructure construction, crews were able to reach pumping equipment from the existing bridge and the trestle. Dorsett trucks received loads from a temporary batch plant erected two miles from the job site. To supply concrete for the drilled shafts of the northbound bridge, Traylor utilized the T-roads extending 90 degrees off of the main trestle for concrete pump set-up. The contractor coordinated lane closures on the existing northbound bridge for ready-mix trucks. Trucks dumped directly into a separate hopper attached to the existing bridge and connected by a chute to the concrete pumps on the trestle. Using this supply system and their Schwing BP 4000 and BP 8000 trailer pumps, Traylor crews were able to complete an estimated 250 cubic yards a day.
The drilled shafts for the northbound portion of the new bridge were completed in July 2004, and the T-roads were removed from the main trestle. The main portion of the crane trestle and the material trestle will remain in place until crews complete the northbound bridge decks. Crews will then concentrate on the demolition of the old Galveston Causeway. Once this is completed, the trestles will be reinstalled and work will commence on the southbound bridge.
Since the completion of the first few drilled shaft pours, the majority of the ready-mix supply, concrete pumping and placement for the northbound portion of the new Galveston Causeway has been performed from Traylor-owned barges.
To supply the concrete for numerous marine pours, Dorsett engineered and erected a complete central mix plant on a barge. Construction took two months to complete, and the batch plant includes all of the essentials to ensure quality concrete: a 10-yard horizontal mixer, a modified excavator with a 2.5-yard hydraulic clam bucket and a 550-volt 1000 amp generator. Admixture tanks and a water chiller for temperature-controlled concrete were also installed. Supplied directly from the batch plant, the concrete pumps provide a homogeneous mix to the KVM 39 separate placing boom through 25 feet of pipe from the pump to the base of the pedestal, then 60 feet up the pedestal to the boom. The 39-meter boom with counterweight can be adjusted to three separate heights. According to Darren Lueking, Traylor Project Engineer, the placing boom will operate from the maximum, 60-foot pedestal height throughout the length of the project. The barge batch plant produced its first yard on February 18, 2004.
Supplied directly from the batch plant, the a Schwing BP 4000 provides a homogeneous mix to the KVM 39 separate placing boom through 25 feet of pipe from the pump to the base of the pedestal, then 60 feet up the pedestal to the boom.
From its position on the batch plant barge, the KVM 39 ballasted boom is operated daily and will place a total 133,000 cubic yards into the Causeway. The boom is equipped with an electric motor to supply power to the boom’s hydraulic pump. An interference-free, wireless radio remote gives operators on the Galveston site fingertip control and clear view of the end hose for accurate, smooth boom movements.
The separate placing boom is also equipped with an autogreaser. “It’s a huge advantage,” said Lueking. “if we didn’t have it we would have to have a member of our crew on a lift or crane and a man basket for the crews to continuously grease all of the pivot points.” “We’ve had great success reaching every necessary angle. Our original plan was to keep the boom in one spot on the barge,” said Lueking. With a vertical and horizontal reach of 114 feet, it looks like the contractor can stick to the blueprint. “As long as we are able to get the batch plant barge into position, the range on the placing boom has been ideal.”
Utilizing their extensive experience and TxDOT guidelines, Dorsett designed and supplies twelve different concrete mixes to the Causeway project, varying between 1500 and 6000 psi. Most are high performance mixes that have high contents of fly ash and micron 3 to protect the structures from the highly corrosive environment. Thus far into the project, corrosive environment components have not had any effect on the pumping equipment.
When the marine-based batch plant is occupied, Dorsett’s land batch plant supplies concrete for construction from the trestle, larger seal and footing pours and aids in some marine work. A Dorsett employee coordinates concrete deliveries with Traylor’s pumps and placing boom each day.
In addition to the BP 4000 and BP 8000 line pumps, Traylor also keeps a Schwing WX 1250 on hand as a backup pump. “We’ve had great success with Schwing pumps, said Darren Lueking, Traylor Project Engineer. “We’re pumping around 30,000 cubic yards of seal concrete into the project. The mix contains 50 pounds per cubic yard of steel fibers. That’s a tall order for a concrete pump, but the Schwings have been able to handle it no problem. We haven’t had to use the back-up pump at all.”
Crews are pumping and placing approximately 1600 to 2000 cubic yards of concrete every week. “Our production numbers are meeting expectations and exceeding deadlines,” said Lueking. “We’re currently two weeks ahead of schedule, and we could have been another three weeks ahead. A rainy June prevented us from working a good portion of the month. But if we can maintain this type of equipment performance, we can look forward to regaining that lead.”
Traylor Bros. depends on Schwing America for reliable equipment and a dependable, nationwide support system. Equipment Coordinator Tom Besing says there are several factors that contribute Traylor’s extensive history and ongoing relationship with the manufacturer. “Schwing is most certainly better represented with their parts and service than other manufacturers. With other manufacturers, you can run into blank spots, where parts and service support is questionable or non-existent. Our work spans the nation, and we require the availability and dependability we get from Schwing America.”
Currently, Traylor Bros. crews are commencing on the main span segmental portion of the bridge. The pier tables, or “starter segments” at piers 37 and 38 are being completed, and with 320 drilled shafts completed on the northbound bridge, girder setting, deck work and segment casting began in October.
With an estimated project completion date of 2008, Traylor Bros. and Dorsett have three more years on the IH-45 Galveston Causeway site. Continue to read Concrete Pumping magazine for updates on this story.