A building construction method that has been used extensively in Europe for years is now rapidly changing construction thinking in America. Developers of hotels, motels, apartment buildings and other multistory structures have chosen the process to produce high-quality buildings rapidly and at low costs. The method uses tunnel forms in combination with electric heat curing to allow the casting, curing and stripping of walls and floors in a 24-hour cycle. Work is programmed so that each day represents the completion of one section or phase of a monolithic structure built with loadbearing walls. The method is concerned with all phases of construction from the basic structure to the finished building, offering savings in cost and labor which are significantly lower than in similar conventionally built structures. The method also reduces erection time.
The construction method utilizes precision-made, rectangular and tunnel-shaped steel forms called porticos that are used to form walls simultaneously with the slab above. When placed end to end they form clean, smooth ceilings and walls that are ready to be painted or finished with other materials. The porticos are rapidly hoisted using a tower crane and placed into position on rolling tracks that have been set on the concrete slab. All reinforcing steel, door forms, wall bulkheads and end-wall forms can be incorporated in the track-aligned multiple forms prior to placing concrete.
The forms used have a distinctive feature: they are electrothermally heated by a patented system controlled by a series of thermostatic monitors. The electric heating system ensures rapid and uniform curing of the concrete and makes the method virtually independent of weather conditions. The system, incorporated into the forms, produces required stripping strengths overnight and permits the removal of forms the very next morning. These forms are again set up and concrete poured the following afternoon to maintain the daily cycle.