What is Tilt-up Construction? (Part I)
In a tilt-up construction project, the building's walls are poured directly at the jobsite in large slabs of concrete called "tilt-up panels" or "tiltwall panels". These panels are then raised into position around the building's perimeter forming the exterior walls. The tilt-up panels are poured into forms that provide the exact size, shape and door openings to meet the design specifications. The largest panel used for a tilt-up construction project weighed just over 150 tons. In some regions the term tiltwall is used interchangeably with the term tilt-up. Tilt wall is a compound word using the terms "tilt-up" and concrete "wall" panels.
A tilt-up construction project begins with job site preparation and pouring the slab. During this phase of the project, workers install footings around the slab in preparation for the panels. The crew then assembles the panel forms on the slab. Normally, the form is created with wooden pieces that are joined together. The forms act like a mold for the panels. Next, workers tie in the steel grid of reinforcing bars into the form. They install inserts and embeds for lifting the panels and attaching them to the footing, the roof system, and to each other. The slab beneath the forms is then cleaned of any debris or standing water, and workers pour concrete into the forms to create the panels. Now comes the point where tilt-up construction, or tiltwall construction, gets its name.
Once the panels have solidified and the forms have been removed, the crew connects the first panel to a large crane with cables that hook into the inserts. The size of the crane depends on the height and weight of the panels, but it is typically two to three times the size of the largest panel. The crew also attaches braces to the panel. The crane lifts, or "tilts up," the panel from the slab into a vertical position above the footings. Workers help to guide the panel into position and the crane sets it into place. They connect the braces from the tiltwall panel to the slab, attach the panel's embeds to the footing, and disconnect the cables from the crane. The crew then moves to the next panel and repeats this process.
It's easy to be amazed as you watch the mobile crane tilt up a panel from the ground and set it into its place. Massive panels weighing 50,000 to 125,000 pounds or more dangle from the crane's long lines. The crew works as a team, setting the braces and guiding the panel with remarkable precision. The speed of the process is also remarkable; an experienced tiltwall crew can erect as many as 30 panels in a single day. Once all the panels are erected, the crew applies finishes to the walls with sandblasting or painting. They also caulk joints and patch any imperfections in the walls. From this point the crew moves to the installation of the roof system and the trades begin their work inside the building.
Precast construction is similar to tilt-up construction, except that the concrete wall panels are formed at a manufacturing facility and transported to the job site by trailer, rather than fabricated directly at the site. This prefabricated panel process provides a more controlled environment for consistent quality, insulated panels and weather protected scheduling.
Precast Concrete, Tilt-up Construction and Tiltwall:
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