Conco Now: News & Updates | The Conco Companies

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.

At The Conco Companies we continue to be a forerunner in the industry with the recently acquired Stud Rail Fabrication certification for our state-of-the-art rebar fabrication facility located in Benicia, CA. We are among only a handful of manufacturers throughout the industry that have obtained this certification. Our Rochester, WA plant is in the process of pursuing the same approval and hopes to have certification by June 2014.

The Stud Rail certification provides a cost-effective solution that simplifies the method of reinforcement for flat concrete slabs against punching shear at the column connection. The prefabricated stud rail assemblies provide the potential for less congestion and increased design flexibility.

Stud Rails Assemblies are an effective way of reinforcing flat concrete slabs against punching shear at column locations. The loads on a concrete slab supported by concrete columns generate shear stresses in the slab. The Punching Shear Studs are a predetermined length and diameter according to design specifications and are in compliance with IBC and UBC Structural Steel Welding Standards. They are used to extend the column perimeter into the floor or foundation slab and have low requirements in terms of formwork and reinforcement. To simplify system design, manufacturers provide free calculation software and other technical support to generate design placing sheets.

With the recent uptake in construction projects getting off the ground, Conco is pleased to acquire another innovative technique to aid in delivering efficiency and cost savings to our clients. We are an approved equal for any project not referencing our ESR-3317 report. A simple substitution request and a copy of the ESR-3317 is all that is required for us to get formal approval to provide those services.

Conco is one of the leading concrete contractors in the Bay Area offering a range of innovative, quality services. We have been honored to work on many high-profile projects and were recently awarded the concrete package for the San Francisco 49ers Stadium. Our concrete services include commercial, educational, parking and other construction development as well as public works projects.

Conco is pleased to announce that we have taken a step toward helping to improve California’s crucial transportation infrastructure. Our $50,000 donation will go toward the significant work being done by Transportation California. This non-partisan, non-profit public interest organization’s mission statement contains “the belief that an excellent highway system is vital to the economic well-being of our state and the quality of life of our people.” Its membership is comprised of business and community leaders as well as individuals.

At Conco we recognize the benefits we receive from the strong growth and development going on throughout California, but at the same time, we understand our responsibility to give back to the community. Our sincere hope is that the contribution to Transportation California will encourage other business leaders to make similar donations toward the good work they are doing. By supporting a well-maintained, modern transportation system, we can all help to facilitate business growth and create more jobs.

The Transportation California’s leadership first became active in 1990 with their effort to successfully pass Propositions 108 and 111, which created the Transportation Blueprint used over the next 10 years. The group came back together after the Northridge Earthquake to formally create the non-profit organization. Their first task was to support Proposition 192 that created separate funding for earthquake retrofitting. This noteworthy bill helped to guarantee that the monies set aside for highway and bridge maintenance and repairs would stay intact. Today, one of Transportation California’s goals is to see that the State continues to address transportation programs that face “massive shortfalls resulting from decades of under-investment.”

While there remains the ongoing discussions of how to pay for new roads, and the repair and maintenance of existing ones, there is a general agreement that the infrastructure has been neglected for over 20 years. Conco’s first-hand experience in the industry gives us a unique perspective to the long-term benefits a strong transportation system provides to the State. We understand that together we can work to improve the roads and bridges that our families travel on every day.

Conco is a leading supplier of concrete services for the Western United States. We got our start in the San Francisco 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.

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.