11,000 YARDS, 16 HOURS, LIMITED ACCESS – WESTERN MAKES THE IMPOSSIBLE, POSSIBLE 2006
From Concretepumping
In the spring of 2005, Western Concrete Pumping, Vista, CA was busy scheduling their Schwing pump fleet for the usual deck pours, slabs, high rise and high-volume pours they are known for on the west coast. As operators and crews proceeded with business as usual, the firm’s general managers were considering Mission Impossible – placing 11,000 yards in one day on a project that would be a logistics challenge and very high profile. Project owner and general contractor Bosa Development, San Diego, concrete contractor Newway Structures, Inc., San Diego, and representatives from Western spent six months discussing the most efficient and cost effective way to complete the foundation pour for Electra, San Diego’s tallest residential tower.
“It’s taken several site plan drafts, several meetings, a ton of phone calls and certainly a lot of cooperation on behalf of every contractor to establish even a semblance of a plan,” said Western Vice President Steve Delamarian.
This extensive, intense strategizing was merited – this was no simple mat pour. One major challenge involved the historical importance of the job site itself. In 1911, the San Diego Electrical Railway Company erected two buildings to house boilers and turbines. The San Diego Gas and Electric Company purchased the property in the late twenties, and were forced to expand the existing facility to accommodate the city’s increasing energy needs. After several years of renovation and expansion, the city of San Diego designated the building a preeminent example of new classical and Art Deco architecture, and therefore an historical landmark. Because of its designation and aesthetic qualities, the city and project owners were forced to build Electra within the old building’s façade. On August 1, 2004, crews installed supportive bracing to safeguard the architectural structure.
From the beginning, it was evident that this three-sided, 90-foot high façade walls would prevent Western from simply setting up pumps immediately adjacent to the 150 by 140-foot excavation. Railroad tracks running immediately to the west of the structure also prevented convenient boom pump set up.
In addition to access issues, Bosa, Newway, ready-mix supplier Hanson Aggregates, San Diego, and Western were faced with the city’s requirement that crews keep interference with downtown traffic and trolley and train schedules to a minimum. Contractors addressed this first challenge immediately, scheduling the monolithic pour to begin and end on a single Saturday.
“Once we agreed to work within that timeline, we needed to figure out a way to generate some pretty outstanding production,” said Delamarian. Crews determined they would need to place 11,000 cubic yards from 5:00 AM to 7:00 PM on October 8. To meet that number, the pour required the output of six mast-mounted placing booms within the walls of the structure and the long reach of four Western boom pumps. Six of the firm’s pumps were needed to supply the placing booms, while one pump was utilized to feed another truck-mounted boom inaccessible to truck mixers.
At 8:00 PM on Friday October 7, Western crews utilized the site crane to remove one 28-meter and two 39-meter detachable booms from their truck-mounted pumps. Utilizing the simple four-pin attach system, the booms were mounted atop masts within the façade in less than an hour.
Western also mounted a rented 31-meter separate placing boom from Concrete Pump Repair, North Branch, MN, to place concrete on the eastern side of the mat. Concrete contractor Newway Structures mounted their own 32-meter boom to place concrete in the center of the pour area. The masts were buried below the mud mat with 11-foot square, 60-inch deep concrete block footings. Once the pour was completed, crews returned to cut-off the masts, fill them with concrete and level the completed foundation. One of Western’s DVM 32 separate placing booms was also erected within the façade for the pour and will remain on site to climb with the forming system as construction continues upward.
Accommodating the pour requirements with the necessary reach was the easy part – Western was also faced with the challenge of supplying those six booms. “We walked right into a logistical nightmare,” said Delamarian. “As far as I know, this has never been done before – there was a lot at stake. But with the support of competent, reputable developers and contractors like Bosa and Newway, we walked into it with confidence. ”
But careful planning and an extensive pump roster supplied solutions for every corner of the mat. In order to supply three of the placing booms from the west side of the building, Western set up three KVM 39 X concrete pumps in a vacant parking lot across the railroad tracks from the job site. Because the city demanded trolley and train traffic go relatively uninterrupted during the pour, the pumper had to engineer and install an extensive underground line system. Crews drilled 10” diameter holes to accommodate an estimated 200 feet of 6” line system running from each of the three pumps. Bored holes in the existing foundation wall allowed pipeline to run directly to the masts of 31, 32 and 39-meter placing booms. One of the KVM 39 X trucks supplied concrete to its detachable placing boom mounted within the facade.
The same underground system was utilized to supply an S 47 SX set up near the south wall of the facade. Tight set up conditions left no room for ready mix access, so Western ran 6-inch line under the railroad tracks from a pump across the street directly to the truck-mounted boom. The pipeline was converted from a 6-inch diameter line to a 5-inch diameter line as it stretched to the 154-foot boom. The S 47 SX was able to access the mat through a low window in the existing façade.
Also positioned on the south wall of the façade, Hanson trucks were able to access Western’s S 58 SX. Its 187-foot boom was able to reach over a low section of the façade wall and into the pour.
Set up behind the S 47 SX on the south wall, a KVM 28 X pump truck took loads from Hanson Aggregate to feed its own detached separate placing boom installed within the facade.
Along the east wall, a S 47 SX required only 27 feet, 2 inches to deploy its Super X outriggers on the crowded downtown street. The boom’s 154’ vertical reach was able to supply concrete to the southeast corner of the mat. Equipped with Schwing-patented Overhead Roll & Foldâ boom design, the operator was able to angle the main section back and feed the boom through a narrow façade window. “We wouldn’t have been able to pull that off with any other boom,” said Western Vice PresidentSteve Delamarian.
Western’s S 61 SX was also set up on the busy east side of the site, offering over 197 feet of reach and affording Western the ability to boom over the 90-foot façade wall.
To feed the remaining 32-meter separate placing boom, Western set up their KVM 36 X on the downtown street along the site’s northern-facing wall. Hanson Aggregate also serviced the nearby KVM 39 X, which fed it’s own 39-meter detachable separate placing boom.
Ready mix supplier Hanson Aggregates said an estimated 200+ trucks serviced the site on October 8. Truck turnaround was expedited through the designation of nearby vacant lot as a washout site.
With nearly 20 years of experience, Western recognized from the start that this project would require a good plan. And in a matter of 14 hours, Western crews turned mission impossible to mission accomplished.
“We knew we’d be able to pull this off. We know better than anyone the capabilities of these machines,” says Delamarian. “It was just a matter of careful, diligent engineering.”
Delamaran credits Bosa Development and Newway Structures for the smooth execution of the mat pour. “Newway’s Ezio Bortolussi and Luigi Aere never cease to amaze this city with their professional performance on these monster highrises. It’s awesome to watch Newway slam-dunk these towers. Bosa’s Dave McCall Loui Rossi and Jim Wessel are priceless commodities.
“Western is lucky to have a pump organization so large,” Delamarian concluded. “We owe a lot to our operators, our operations manager Don Campbell, our highrise systems director Brent Hughes and equipment managers Dave Ripka and Tom Laverty. We couldn’t have pulled this off without the collaborative efforts of everyone involved.”
Upon its completion in December, the sold-out Electra will feature 248 units and measure in at 43 stories high.
