Concrete Pumping Archives | Page 23 of 29

Pumping concrete safely requires a comprehensive commitment throughout the entire organization. Having pumped millions of yards of concrete over the past 50 years, The Conco Companies have developed and implemented some of the most rigorous pumping safety procedures in the entire concrete industry.

Safety starts by insisting that all Conco pump operators attain American Concrete Pumping Association (ACPA) certification. ACPA training teaches our operators all aspects of the safe operation of a concrete pump. This training must be completed every two years and covers all operational and safety issues that might be encountered by crews. Our operators are taught how to operate their equipment safely and also how to protect all those that work around the pump from harm.

In addition to ACPA certification and company specific safety training, Conco obtains inspections of all of its boom pumps and Telebelts every year by certified boom pump inspectors. This inspection ensures the structural integrity of the equipment we operate.

Boom pipe cumulative yardage pumped is also tracked so Conco can be certain that pipes are changed on regular intervals in order to avoid pipe failures in the field. Our boom pumps are also equipped with a transition cover designed to protect people working behind a concrete pump (namely ready mix drivers) from injury caused by an unforeseen pipe elbow blowout.

Finally, Conco Pumping has purchased more than $10 million in new boom pumps and Telebelts in the last 18 months. This new equipment helps us provide our customers one of safest, most up-to-date and CARB compliant fleets on the west coast.

Conco’s commitment to safety isn’t just talk. Our pumping division completed 2013 without a single lost time accident, and our goal is to repeat this performance, year after year.

The first quarter of 2014 saw some significant projects being completed for The Conco Companies. Concrete work for the new Levi’s Stadium (home to the San Francisco 49ers) is virtually complete as only minor concrete remains. The goal posts have been installed and the seats are in as the stadium gets ready for an on time opening this summer. Conco has placed more than 67,000 cubic yards of concrete without a single injury or accident of any kind.

In Seattle at 815 Pine, we poured the final deck (Level R2) on March 20, 2014. This was the exact day shown on our original contract schedule from August of 2012! Regardless of the weather impacts from two Seattle winters and any unforeseen challenges which presented themselves throughout the construction, Conco deployed the resources and equipment needed to keep the project on track, as committed.

In addition to these two signature properties, Conco has completed 15 other sizable projects in the first quarter including high-rise office buildings, mid-rise office buildings, multi-story apartment buildings, parking garages, hospitals and a casino.

Looking forward, Conco’s backlog continues to grow but our continual reinvestment in the construction industry with new equipment and added personnel along with our ability to complete projects on time and on budget will help us satisfy our customers’ needs on new jobs in the future.

Raising the Environmental Bar on Concrete Pumping

The Conco Companies have been busy working on the new Wilshire Grand Center in Los Angeles, which is slated to become one of the tallest buildings west of the Mississippi. Before the start of the project, we were asked how we will pump concrete 650 feet horizontally and then 1,125 feet vertically to reach the upper levels of the skyscraper? Additionally, since we would be pumping concrete higher than was ever pumped in Los Angeles, could this be done without generating air pollution or creating too much noise for the adjacent office buildings?

Conco’s unique solution was to purchase and use a new state-of-the art electric pump. This high pressure, high powered pump is the only electric pump of this size being used on the West Coast by the concrete pumping industry. Since it is electric, this pump allows both the project owner and the contractor to meet the guidelines imposed by the Southern California Air Quality Management District (SCAQMD) for reduced emissions.

Another benefit of the electric pump is that it generates much less noise than a traditional diesel powered pump. This is important as the pump must sit less than 30 feet from an occupied office building, which makes it less disruptive to the neighboring businesses.

The new pump will be the primary workhorse in pumping concrete throughout the course of the project and it will be used to pump concrete all the way to the top of the skyscraper. We are anticipating that we will pump more than 100,000 yards of concrete through our electric pump to complete the Wilshire Grand project.

Conco is a leading supplier of concrete services for the Western United States. We have built our reputation with superior concrete formwork, reinforcing, place and finish, shotcrete and other ancillary services that benefit from our vast experience. Our concrete projects include commercial, educational, parking and other construction development as well as public works projects and highways.

While Conco is justifiably proud of breaking the World record for the largest continuous mat pour, we are even more proud of doing it safely. Our commitment to safety began with the vision from Conco’s Southern California General Manager, Rick Parker. Five months prior to the pour, he invited John Messing, Conco’s Safety Director, to participate in the planning meetings for the Grand Pour. Rick has learned from his years of experience that projects go more smoothly when the safety department is involved early-on to ensure that safety is built into the overall work plan.

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*Photos provided by Gary Leonard

Rick also made the prudent decision to devote the first-quarterly company safety meeting in January entirely to the safety of the pour. During the meeting, Rick Parker and Pumping Manager, Doug Marquis, provided an overview of the Wilshire Grand jobsite along with the challenges, unique project features, and logistical considerations of the job. John Messing spent the balance of the time devoted to discussing the importance of pre-task plans. He assigned three sub-groups to develop such plans regarding the work that they would perform. At the conclusion of the safety meeting, the pumping crew, place and finish crew, and street-level supervisors all had a unique, customized pre-task plan that was used as the basis to ensure their workers understood the hazards of the work and how to mitigate them.

The end result of the successful well-thought out plan was a highly professional team effort from all Conco employees. The entire team—at all levels—executed the plan to perfection, which resulted in zero injuries for this world record continuous concrete pour.

Among the many unique features of the Wilshire Grand mat foundation pour was the thermal control plan. Occasionally we need to make provisions for the heat that is generated in mat foundations. In mass concrete structures there are two thermal properties that must be considered: the maximum temperature and the temperature difference between the center of the structure and surface.

There are multiple ways to control the overall thermal properties of mass concrete. For the Wilshire Grand pour, one of the first things Conco addressed was the concrete mix design. There are a few common adjustments that can be made to the actual mix, but they all have some impact on the production rate when the concrete is being batched. In this case, working with our supplier Catalina Pacific, we increased the proportion of fly-ash which normally results in reduced maximum temperatures.

The next step was to mechanically control the temperatures. Pre-chilling the concrete was not an option due to the rate that we needed to batch and place the concrete. Nor was there a way to feasibly pre-chill 21,200 cubic yards of material ahead of time so we had to consider post-chilling by means of cooling pipes to mechanically remove heat.

For this, we turned to John Gajda of the CTL Group. CTL developed a thermal control plan specific to the mix design, the geometry of the foundation, and the configuration of the rebar. With help from Couts Heating and Cooling, we implemented CTL’s thermal control plan. Ultimately the system we installed to post-chill the concrete was composed of 18 miles of cooling pipes, over 660 tons of chiller capacity, 40,000 gallons of chilled water, multiple pumps, 3 x 500kva generators, and over 2,200 valves. This includes a large amount of contingency and redundancy for reacting to unanticipated thermal phenomena and providing backup during the critical early stages of the thermal control plan.

Subsequently we installed 24 thermal couplers to digitally monitor the thermal properties of the concrete. For assistance, we teamed up with Twining Laboratories who were able to provide hourly readings of the foundation utilizing Intelirock equipment. By monitoring temperatures closely, we could respond by increasing chiller capacity and/or adding insulation if required. Furthermore, monitoring allowed us to determine when the thermal control system could be removed and the concrete core started.

In the end the thermal control system was a success. The maximum temperature was kept below ACI limits and the temperature difference was well within the ranges required to avoid thermal cracking.

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