For California steel contractor CW Services, boom lifts were the only solution to a difficult jobsite. ALH reports
By Lindsey Anderson14 August 2012
There's little denying the value boom lifts bring to the jobsite: improvements in efficiency safety and productivity are inherent benefits the technology affords its users. Occasionally, however, a situation arises when even the traditional straight boom simply won't do and companies have to seek out a specialty tool to keep things happening onsite.
For steel contractor CW Services, that situation was an extremely challenging tilt-wall construction project in Torrance, south of Los Angeles. Faced with daunting access issues, the company turned to American Rentals to find an alternative approach and got it in a series of Genie articulating boom lifts from Terex Aerial Work Platforms. CW officials report that, with as many as five different Genie booms on site at once - four of them articulating models - they were able to tackle some critical facets of the construction while keeping the project moving along and their reputation for quality, on-time work, intact.
Torrance of Activity
The Torrance Memorial Specialty Center (TMSC) is a three-story, 66,000-square-foot structure that, as the name implies, will house medical specialists affiliated with the Torrance Memorial Medical Center located nearby (itself undergoing a massive expansion). Started in January 2011, the TMSC features a tilt-wall construction design which, while somewhat traditional in scope, has a number of features that presented challenges to crews involved in the project.
"For one thing, a three-story structure is not typical for this type of construction," says Reuben Salcedo, CW Services' project manager. "Tilt-wall is usually limited to two-story designs. However, what made this job challenging from our perspective was the fact that it involved placing and bolting or welding more than 1,200 separate I-beams. With those in place, the tilt wall sections were raised and held in place with shoring. Then, we had to begin bolting and doing a series of critical full-pin welds which involved coming in from the back through all that shoring. So, during the early phases of construction, most of our work was done on the inside of the structure rather than the outside."
During each facet of the project, Salcedo says the Genie Z-booms (both Z-45 and Z-60 models), were a key component, largely because of the accessibility they provided.
"The design of the boom with the jib on the end of it, made the process of reaching in and getting around things much easier than we'd imagined," he says. "There were also a number of bent plate areas which we had to access from the bottom and it was also a breeze. On this job, these booms did things that a straight boom simply wouldn't have been able to do."
The tilt-wall design at TMSC was interesting from a number of other perspectives as well. Craig Blanch, Superintendent and Safety Manager for general contractor, 2H Construction, says that certain segments of the design itself added an element of challenge to the project.
"Unlike most structures in which the windows are placed directly above one another, on this one they are staggered, so there is no continuous run of rebar going up from the ground. That complicated our lift procedures. Then, it was decided that the concrete mix should be changed to a Type 3 Cement to achieve a whiter color. Unfortunately, while that mix strengthens early, it is also brittle, so that had to be taken into consideration."
To address any issues that might have arisen, Blanch says they created a half-size mockup of each panel complete with all the rebar, imbeds, and so on. Each 10-foot by 22-foot panel featured not only two windows as on its full size counterpart, it also included the third floor lights that pop up to illuminate the canopy overhead.
"Taking that approach actually identified a small design flaw. We offered an alternative approach using different lights, proved it out on the mockup, showed it to the architect and made the change. It really worked out well for everyone."
Dealing With It
As the general contractor, Blanch says he recognized the difficulties facing CW Services during the early part of the construction process, but also appreciated the manner in which they addressed those challenges.
"That's really one of the things I like about dealing with their company," he says. "In construction, issues and problems are part of the business. But they never come to us with a problem alone, they always have a solution, a proposed way to fix it. Their approach to dealing with the panel brace issue is a good example of that."
By way of illustration, Blanch says that, once each panel was lifted and braced, the roof and decking were installed and, at that point, two major beams had to be locked in at the third floor level of each panel, basically right where the braces were attached. The braces had to remain in place until each panel was locked and squared off in two different directions.
"It was really congested in there," he says. "It was just wall-to-wall braces, and in areas in which you didn't see braces, you saw booms. But that's where those special booms paid off. "Using any other type of reach would have just been a nightmare. Also, the schedule on this job was so aggressive that, for a short time, CW fell behind. But they got things back on track by increasing manpower, putting in extra hours and, with the help of those articulating boom lifts, making it happen. Their guys got really well-versed in the value of those articulating booms. It was awesome."
Tilt-wall projects are far different from traditional type of construction in that most of the prep work is done on the ground, essentially unseen to outside observers. Such was definitely the case at TMSC. Adjacent to the structure, H2 created a pair of massive "waste slabs" on which the panels were formed and poured out. Only a 50-foot buffer area off the face of the building was left clear to allow access for the crawler crane which would lift the panels into place.
"Driving by this site when all the prep was being done, it would appear there was nothing being done for two months," says Blanch. "Then, in two days, there was a building. We pumped cubic yards of concrete to create all the panels at once -starting at 1 a.m. in the morning and finishing eight hours later, a pace that was driven by the fast set-up time of the Type 3 cement."
The nighttime pour also made sense from a quality standpoint, given that the heat of a California afternoon can result in thermal expansion and bubbling problems on the panels' surface. "At night, when it was cool, there were no plywood joints showing up in the panels at all; it was smooth as glass," says Blanch.
The American Way
The relationship between the contractor and his equipment supplier is an important one and CW's Salcedo says he appreciates the efforts put out by American Rentals and Tim Pfeiffer, their salesman.
"Tim and I actually go back quite a few years to when both of us were with different companies," he says. "But that familiarity paid off in him knowing how I like to work, anticipating our needs and bringing it all together for us. American also has a great reputation for maintaining its equipment well, and that can make all the difference."
Even after CW Services wrapped up the demanding inside fabrication, they continued to rely upon the boom lifts for much of the exterior work, including everything from a screen wall at the top of the structure, to an overhang above the main entrance. In fact, Salcedo says some of the lower work benefited from the booms' ease of access as much as the upper projects.
"While some areas could have easily been reached using a tall ladder, welders have tanks and other equipment to which they need access," says Salcedo. "Being able to have all that in the basket of the machine and then simply slip underneath an area to make welds is both safer and a real time saver. We couldn't have been happier with the Genie equipment and with the support we got from Tim and American. They made a tough job very do-able."