Concrete Pumping Archives | Page 24 of 29

To successfully complete the world’s largest continuous mat pour, one of the biggest challenges Conco faced was to find ways to unload 120 – 150 truckloads of concrete per hour. With the need to unload so many trucks in such a short period of time, Conco’s plan called for thirteen points of placement in the mat foundation. However, only two sides of the project were accessible from the street.

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Since the site only provided access for seven pumps to be positioned to pump directly into the building foundation, Conco’s plan needed to have pumps that were pumping into pumps. Pumps were dropped by crane into the excavation site and two placing booms were fed from pumps nearly 400 feet away. In all, fifteen boom pumps, two high-pressure stationary pumps, two placing booms, and more than 2,500 feet of pipe operated throughout the pour to get the concrete to the foundation. Four of the pumps on this project were new along with a brand-new placing boom. In addition to this equipment, three boom pumps were parked in close proximity to the project in case of a breakdown. None of the backup pumps were put into service as the pumps on the job performed near flawlessly.

To complete the rest of this signature project, the two high-pressure stationary pumps will remain on-site for the project’s duration. One of the pumps is a recently purchased electric pump. This pump is the most powerful electric pump operating west of the Mississippi and is capable of pushing concrete to the top of the structure. It provides our client, the Turner Construction Company, with a zero-emission pump that operates with less noise than a typical diesel pump.

By the end of Conco’s record breaking mat pour, the pumping work all went successfully according to plan. Special recognition goes to our ACPA trained pump operators, and our mechanics that spent countless hours preparing the equipment for the pour.

*Photos provided by Gary Leonard

Starting at 4:47 p.m. on Saturday, February 15, 2014, Conco broke the Guinness World Record for the largest continuous mat pour in 18 ½ hours (1 ½ hours under the projected time). To verify the event, there was an official Guinness World Records adjudicator on-site. The mat pour was for the new Wilshire Grand Center that is being constructed in downtown Los Angeles, and is slated to become the tallest building in the U.S. west of the Mississippi.

*Photos by Gary Leonard

After some 5 months of excavation and shoring, Conco was finally ready to begin the preliminary mat foundation work. Starter footings and elevator pits had to be constructed before the nearly 7 million pounds of mat reinforcement was installed. Then came 18 miles of cooling pipes for thermal control. We were ready to go with a couple of days to dot the i’s and cross the t’s. We began the set ups for pumping which involved strategically placing 19 pieces of concrete placing equipment in and around the construction site. It was now time to place this nearly 20 foot thick mat foundation.

The massive mat pour required a fleet of 208 trucks that each made 10 to 14 concrete drops for a total of 2,100 trips over the 18 ½ hour period. All of the concrete was provided by eight concrete batch plants operating at full capacity and located within a 20-mile radius of the job site. The success of the pour depended upon everything going exactly as planned and with contingencies in place to reroute trucks around any traffic jams. Trucks had to arrive on time since concrete needs to be poured 90 minutes after it is mixed. Several streets in the area were closed off to traffic.

Prior to this record breaking event, the largest continuous mat pour had been for the Venetian Hotel in Las Vegas in 1999. During that event, 21,000 cubic yards of concrete were poured. For the Wilshire Grand, 21,200 cubic yards of concrete were poured with an official finish time of 11:30 a.m. Sunday morning. The skyscraper is expected to be completed in 2016 and opened to the public in 2017. The Wilshire Grand will be 1,100 ft. tall, to include a 900-room hotel, office and convention space as well as five levels of subterranean parking.

After the highly publicized reports from this past summer regarding the failure of 32 anchor rods on the eastern span of the new Bay Bridge, the highly regarded concrete contractor, Conco was retained by the general contractor, American Bridge/Fluor Enterprises, Inc. JV, to assist with the repair work. Based on their earlier performance with other critical and technically challenging components of the new bridge structure, Conco was the logical choice. “Every aspect of this project had complex technical challenges.” said Brian Petersen, the contractor’s Project Director, and “Conco’s skill and expertise was a great asset to our team.”

The defective anchor rods were supposed to secure the bridge deck to the concrete crossbeam support. Since the failed rods were embedded and inaccessible, replacement was not feasible. After extensive collaboration and analysis, a fix was designed. It involved a complex series of steel saddles and post-tensioned (PT) jacket walls that would provide the required clamping force to secure the bridge deck framing to the E2 crossbeam. Temporary steel shims were inserted into the stabilizers while the repairs were being done, and in order for the Labor Day opening to go forward as planned. “The SAS bridge is part of a world-class megaproject which features a large amount of challenging concrete work associated with temporary support structures that are not part of the completed bridge,” noted Jim Klinger, Conco’s project manager.

For this very complicated problem, Conco’s first task was to close in a steel-framed trestle platform to give work crews access to the site and eliminate the potential for materials to fall into the San Francisco Bay. Once the platform was complete, crews roughened the crossbeam surface and epoxied over 3,000 drilled dowels into place. Reinforcing steel and PT cable ducts were then installed by Harris Salinas. Conco crews followed behind them, placing custom-made PT trumpet blockouts and setting forms for the jacket walls.

The concrete jacket wall structures were placed in three pours totaling 380 cubic yards. Due to restricted access and rebar congestion, much of the concrete had to be pumped 250 feet and then injected into the forms through ports at strategic locations. Conco worked closely with concrete supplier, Central Concrete, to develop an injectable SCC mix with silica fume that would meet the project’s specifications. A full-scale mockup was constructed and successfully tested to ensure the long-distance pumping and injection of the highly-flowable SCC mix would work.

“Almost all of the concrete work items Conco was asked to perform by ABFJV were custom, one-of-a-kind scopes that we will probably never see again,” said Klinger. In late November, the third and final injection was finished and the repairs were completed successfully.

Conco is a leading supplier of concrete services for the Western United States. As one of the leading commercial concrete contractors in the Bay Area, we have been involved with large-scale projects in the area including the new 49ers Stadium. Our concrete services include commercial, educational, parking and other construction development as well as public works projects and highways.

Conco is once again an essential part of a team that is constructing the new Kaiser San Leandro Medical Center by providing concrete services. The facility is scheduled to open this year. The overall project consists of 740,000 sq. ft. of new construction, which includes a six-story, 436,000 sq. ft. hospital with 264 licensed, acute-care beds. The Medical Center will also have a new central 30,000 sq. ft. utility plant to house the mechanical and electrical equipment.

The plan calls for an abundance of surface parking for up to 2,100 vehicles, and a 275,000 sq. ft. Hospital Support Building that is connected to the main hospital. The 63 acre lot is located just off the freeway, which makes it highly accessible, and the new Center will be a replacement for the old Kaiser Hayward Hospital. Since the new construction covers only 30 acres, there is plenty of opportunity to showcase the scenic rolling hills on the property.

This is Kaiser’s eighth template hospital, and while it is still constructed to be site-specific, it reduces building costs by approximately $89 less per sq. ft. The project is designed by Hawley Peterson & Snyder in association with AECOM partner, Ellerbe Becket. The general contractor for the Medical Center is Rudolph & Sletton, Inc. and the engineer is Rutherford & Chekene. This is Rudolph & Sletton’s third hospital project they have worked on with Kaiser over the last few years. According to their website, “This ‘second generation’ template hospital, which reflects Kaiser Permanente’s program to establish standardized, yet customizable, state-of-the-art models for design and construction of its hospitals, includes the latest technology for patient care and support.”

Conco performed all of the structural concrete work for the project and belted and placed more than 18,000 tons of aggregate underslab material. In addition, the project incorporated sustainable design features based on the Green Guide for Healthcare as well as environmentally responsible purchasing. A prime example is during the demolition of the old building on the property; close to 97% of all waste was recycled on-site including grinding up old concrete. It was used in the soil mixture process and for fill and pavement base. It is estimated that 98,000 tons of construction waste material was diverted from landfills.

Conco is a leading supplier of concrete services for the Western United States. We got our start in the Bay Area in 1959 by offering clients the best value on a wide range of concrete services and products. Since that time, we have steadily taken a leading role as one of the Bay Area’s top concrete contractors. Our concrete services include commercial, educational, parking and other construction development as well as public works projects and highways.

Conco is seeing an increase in building projects coming out of the ground and being planned for the near future. To help us meet the demand, we have made significant capital investments to increase capacity at our rebar fabrication facilities and purchased new equipment. We have also expanded our geographic footprint which now includes having a large presence in Washington State.

One of the projects we are involved with there is 815 Pine, a luxury, 40-story apartment building adjacent to the historic Paramount Theatre in downtown Seattle. The Pines is the tallest residential tower to be built in the downtown area in the last several years. It is expected to open for early occupancy in November 2014 and should be completely finished by April of 2015.

The building is being constructed by the Holland Partner Group, and as part of the team, Conco will perform the concrete services. The job involves doing all of the cast-in-place concrete, rebar, formwork, shotcrete and concrete pumping for this signature property.

Since the location of the building is right in the heart of downtown Seattle, the small footprint with a minimal lay-down area and a five-day form cycle presents some challenges. To ensure jobsite safety and to meet the aggressive schedule, Conco will use a perimeter protection system as well as a perimeter netting system.

Once completed, 815 Pine will have 386 apartments with 265 parking stalls on 9 levels. Apartments will vary from 450-square-foot studios to 1,250-square-foot three-bedroom units, and in the New York tradition, will have a 24-hour doorman. The total size of the building is 488,193 gross square feet, and is designed and constructed to achieve LEED Silver status.

For over 50 years, Conco has been providing premium concrete services and is one of the most trusted concrete contractors in Seattle. We partner with clients on every project from the pre-construction stage right through to final completion to maximize efficiency and ensure goals and budgets are met. Our concrete services include commercial, educational, parking and other construction development as well as public works projects.