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In Their Own Words: General Construction Company Engineer Veronica Moczygemba talks about the foundation work.
This is the third in an occasional series of guest articles written by people engaged in the construction of the new East Span. This installment was written by Veronica Moczygemba, an engineer with General Construction Company.
When the opportunity to move to the San Francisco Bay Area from the beautiful Emerald City in Washington State arose, I jumped at the chance. As much as I love Seattle and the Great Northwest, I felt this was a once in a lifetime project and well worth the move. So far, the relocation to sunny California has been a good experience and everyday presents a new challenge on the job.
I am an employee of General Construction Company (www.generalconstructionco.com), a wholly owned subsidiary of Peter Kiewit Sons. I am one of the concrete engineers for the substructures of the bridge. General Construction, based out of Poulsbo, Washington, specializes in marine construction and is part of the Kiewit portion of the joint venture for this project. Like our joint venture partner, Manson, we have a large fleet of floating equipment and are working together with our sister company, Kiewit Pacific Co., and FCI to build the substructures of the new bridge. In addition to construction of bridges, dams, and piers, General Construction also has a flourishing industrial group that includes large precision machinery installation and facilities maintenance for companies like Kimberly-Clark/Georgia Pacific and Boeing.
The bridge has 28 footings. Each footing consists of a large steel box which houses the piles that penetrate deep into the bay. The box footings arrive on site via barge from Corpus Christi, Texas, and are lifted and set into place by a catamaran capable of lifting 2000 tons. Before the boxes are set, they are partially filled with concrete to a depth of 1.5 meters. Once inside the cofferdam, the pilings are driven and welded into place and the boxes will be filled to another 4 meters in depth of concrete, poured in two separate lifts. Each footing box will be filled with an average of 1350 cubic yards of concrete. After it's all said and done, over 37,000 cubic yards of concrete will be poured into the foundation box footings; that's enough concrete to fill 11.5 Olympic sized swimming pools, but less than 1% of the 4.5 million cubic yards of concrete used to build the Hoover Dam. Unlike the Hoover Dam that used enough concrete to build a 4' wide sidewalk all the way around the equator, our sidewalk would only stretch 145 miles.
With the help of the substructures team and the direction of the concrete superintendent we will pour all of the concrete in the foundation boxes of the bridge. What I have found to be the most challenging to this point is all the planning required to bring all the different facets of the job together. This project began in February of 2002 although crews didn't start working until the summer of 2002. I arrived at the jobsite last year in June and after months and months of planning and waiting we have finally begun to pour concrete. On December 23, 2002, the first foundation footing box arrived on site and a few days later we poured the first 1.5 meter lift of concrete.
The process of actually pouring the concrete was really very simple in comparison to the amount of planning and scheduling that went into making pour day happen. Concrete is placed by means of a pump truck and a 4" metal pipe placed in the top of the box through 4 ½" diameter holes. Issues such as fall hazards and general safety, access to the top and inside of the boxes, the type of concrete to be used, and how to keep the concrete from cracking were only a few of the problems encountered. Additionally, we needed to work with the rest of the substructure crews and Caltrans so that the overall schedule was met. After a strenuous review process, all issues were resolved and a final plan put into action. Ironically, over 8 months of planning went into an operation that was complete in less than 8 hours. Keep in mind, this was the first of 28 pours, so if the time is divvied up, each 1.5 meter lift pour takes approximately 9 hours to plan which is still longer than it takes to pour the concrete. Such is the nature of the beast!
Although such planning and scheduling may seem excessive, it's important to remember that the foundation box concrete is only one small portion of the job. Other operations include coffercell, rock, and rebar installation, pile welding, access trestles, post tensioning, segment erection, and more. KFM will employ over 400 staff and craft personnel at the busiest times during the project, and with that many players involved, communication is of the essence. Construction of this hallmark project will be a total team effort and as time consuming and sometimes painful as the planning process seems, the end result will be well worth the sweat and effort and I'm glad to be a part.
KFM's Brawn Lausen on the Skyway section's Italian connection. December, 2002.