March 1991 Table of Contents

Features Introducing Tilt-Up into a New Market

The author of this article, an Australian, formed a tilt-up construction company called Advanced Building Systems Party Ltd. after seeing many tilt-up innovations in the United States. His next step was to gain the acceptance of the Australian market for the tilt-up system. He decided to design and build a 50,000-square-foot tilt-up factory and hold a demonstration on the day of panel lifting. While most of the attendees were amazed at what they saw, the developers were still skeptical. To get the attention of the developers, he had to prove that tilt-up can save money. Research showed that they could build a tilt-up building 15 percent cheaper and 25 percent faster than a conventional building. This meant initial savings for the developer of $150,000 per $1 million. Read more

Features Under Fire

Fire fighters have wondered if the roof support system in tilt-up buildings burned down, would the walls collapse? They didn't in March 1986 when a severe fire in a Phoenix tilt-up building consumed the entire wood roof system. The building, a U.S. postal annex built around 1970 was constructed of 5.5-inch-thick tilt-up concrete walls with a wood roof system. The plywood roof deck was connected to a ledger consisting of a 6 by 8.2 steel channel with a wood nailer attached. After the fire, all that remained of the roof system was the middle one-third cross section of the laminated girders. The walls deflected out 6 to 8 inches on the north, west, and south sides of the building. Aggregate popouts and large panel deflections suggested a very hot fire. Read more

Features Tilt-Up Under the Big-Top

Frustrated too often by Lansing, Michigan's winter weather, Larry Clark of L. D. Clark Building Co. decided to do something about it. After a year of planning and preparation, his solution is anair-inflated dome enclosing and supporting its own working environment. Regardless of theweather, inside conditions can be maintained to keep workers efficient and product quality high.The dome, a 213-foot-long by 150-foot-wide and 45-foot-high bubble of 28-ounce vinyl-coated polyester, is supported by 1 psi of air pressure. Air for support, heat, and ventilation is supplied by a 1-hp electric blower unit enclosed in a 45-foot semitrailer and routed to the dome through 30-inch ducts. The dome transmits light well so little extra lighting is needed during the day. Read more

Features Construction of Elevated Concrete Slabs

Most contractors and engineers agree that elevated concrete slabs don't always deflect as intended. Measurements are necessary to identify the areas in which practice departs from theory and to determine what adjustments are needed to improve the quality of the next concrete slab placement. A continuous cycle of placement, measurement, evaluation, and adjustment produces high-quality elevated concrete slabs and satisfied owners. Read more

Features The Mechanics of a Trench Collapse

Several hundred people die each year in trench collapses. Unfortunately, production and safety goals seem to be at odds when dealing with trench work. The soil that snuffs out life in a trench collapse is not only suffocating, it is crushing, weighing easily 120 pounds per cubic foot. To put that in perspective, keep in mind that a cubic yard is as heavy as an automobile. Read more

Features Tilt-Up and Trompe l'Oeil: a Perfect Match

Trompe l'oeil, or fool the eye, is a style of painting in which architectural details or scenes are depicted with photographic clarity. This style, used centuries ago by Roman nobility, is now enjoying a resurgence in the United States. A leader of this revival is Richard Haas, an internationally recognized artist from Chicago. In 1985 he used trompe l'oeil to turn the Thunderbird Fire and Safety Equipment Corp., Phoenix, Ariz., into a masterpiece of illusion. Two sides of the tilt-up building are trompe l'oeil. Read more

Problem Clinic Removing Footprints on a Floor

We have footprints on a floor that has a hard-troweled finish with a black day shake hardener. The floor was sealed with a high solids acrylic cure and seal product. We've used a steel wool buffer to try to remove the footprints which are in an approximat Read more

Problem Clinic Clumps of Dry Material in Ready-Mix Discharge

When our ready mix trucks discharge concrete, drivers sometimes report seeing balls of nearly dry material coming down the chute. When broken open, the balls appear to be mainly cement and sand with some coarse aggregate particles in them. What causes thi Read more

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