Using an innovative method combining earth anchors and shotcrete, foundation contractor Schnabel Foundation Co., Cary, Ill., temporarily shored a deep roadside excavation. Earth on one side of a quarter-mile stretch of the roadbed was about 25 feet above the proposed grade. Normally, excavating such a hill down to grade would require the use of sheet piling or soldier piles and lagging to shore the embankment until a permanent retaining wall could be built. But Schnabel determined that it could do the job more cost effectively by using earth anchors and shotcrete -- a method the contractor had used successfully on other projects.
By definition, a custom wood form is one that is designed and built for a specific concrete structure. Many contractors find it more economical and efficient to use the prefabricated, modular forming systems now available.
A job at Illinois State University presented this contractor with several challenges. Watterson Towers in Normal, Illinois, is a 27-story student dormitory, consisting of twin towers for student rooms with a free-standing elevator shaft between them.
Total forming costs may easily be 48 percent of the cost of a concrete wall. This makes it very worthwhile to evaluate a number of form systems to determine which will be most efficient and economical. This article will provide some help in choosing wall forms, but it covers only gang form systems. However, the methods of analysis may be adapted to other forming conditions.