The purpose for the boom pump being lifted and turned for each side's pours was because the pipeline leading from the trailer pump to the hopper of the 52Z-Meter would be in the way of placing the concrete if the boom pump was not lifted and turned each time.
The trailer pump was also moved back and forth for each side's pours and connected to pipeline.
Although Obayashi/PSM JV had used a concrete ready mix supplier earlier in the project, in late 2007 they began operating their own concrete batch plant. For the deck pours, they used a harsh 4,500-psi mix with fibers in it to help control cracking on the deck. Because this was such a tough dry mix, using the right trailer pump was crucial.
Another challenge was how far horizontally the concrete would need to be pumped. The crew decided to use Quinn's BSA 14000 to pump a distance that started at 700 feet and reached a maximum of 950 feet through pipeline, plus another 170 feet through the 52Z-Meter.
With the highest pressures and outputs available, the high-performance trailer pump easily maintained a continuous flow of the harsh mix and facilitated the long-distance concrete pumping.
"First we pumped through the pipeline and into the hopper of the 52Z-Meter, which then pumped the rest of the way," explains Wes Pollnow, construction manager for Obayashi/PSM JV. "The trailer pump really provided the power we needed to push the concrete up and out to its final destination. It averaged 75 cubic yards per hour and at one point reached 100 cubic yards per hour. The trailer pump provided a smooth, controllable output of concrete because of its free flow hydraulic technology. Its fully adjustable volume control allows for very slow pumping while retaining full concrete pressure."
The trailer pump pumped the concrete at 4,060 psi and the 52Z at 2,175 psi.