What's the Difference in These Terms? (Part II)
Several terms - tilt-up panel construction, tiltwall construction, precast concrete building construction - are used to reference new or nontraditional cement building processes. What are the differences? Tilt-up and tiltwall are two terms used to describe the same process. For a tilt-up concrete building, the walls are created by assembling forms and pouring large slabs of concrete called panels directly at the job site. The panels are then tilted up into position around the building's slab. Because the concrete tiltwall forms are assembled and poured at the job site, no transportation of panels is required. One major benefit of this is that the size of the panels is limited only by the needs of the building and the strength of the concrete panels themselves.
Tiltwall panels can sometimes be extremely wide and/or tall. Tilt-up panel have been measured at just over 69 feet across and almost 93 feet from top to bottom. Thus, architects and tilt-up concrete contractors have a great deal of flexibility in planning and creating their buildings. Because concrete tilt-up walls are poured outdoors, contractors are at the mercy of climatic conditions. When temperatures drop below freezing, curing the concrete panels becomes more difficult and expensive. Certainly, tilt-up concrete buildings are built in northern areas, but the window of time for temperate weather is much smaller and less predictable, which can make construction schedules more difficult to meet.
The precast concrete building process is similar to tilt-up construction, but it addresses the challenges presented by weather. For precast concrete buildings, work crews do not set up forms at the job site to create the panels. Instead, workers precast concrete panels at a large manufacturing facility. Because the precast concrete forms are poured indoors, this activity can take place regardless the weather conditions. After curing, the precast concrete panels are trucked to the job site. From this point, precast concrete buildings are assembled in much the same manner as tiltwall buildings. The fact that precast concrete walls are formed at a manufacturing facility resolves the weather issue, but presents a different limitation not found in tilt-up construction. Because the panels must be transported - sometimes over long distances –it places a substantial limitation on how wide or tall each panel can be. It would be impossible to load precast panels that were 60 feet wide or 90 feet long onto trucks and transport them any distance.
For a precast construction project, the panels must be smaller and more manageable to allow trucks to haul them over the road to their final destination. This places greater design restrictions on architects and limits the applications where precast construction can be used. Clearly, tilt-up or tiltwall construction and precast concrete are similar processes. Because tilt-up affords more flexibility, it is the method of choice in locations where the weather allows it. Precast concrete is a suitable choice in circumstances where environmental factors and the construction schedule preclude tiltwall as a viable option.
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