Cast-offsite
bridge and roadway components.

Because of their size and weight, precast segmental bridges are usually cast on or near the job site. In 1997, Unistress decided to re-think that approach, starting with the nation’s largest-ever urban highway reconfiguration, the Central Artery / Tunnel Project in Boston.

We cast the segments in our plant at the other end of the state, far from heavily-congested downtown Boston. Using specialized match casting techniques and complex rebar cages to meet very exacting tolerances; we overcame production and transportation challenges, and still met an unyielding project schedule.

Pre-fabricated stair-box forms.

Garage stair and elevator towers are typically constructed using individual walls, braced and welded together in the field, with stair risers then inserted and welded to the walls. This process, although less time consuming than construction in steel or other materials, slows the otherwise rapid construction of a precast parking garage.

Unistress has developed an innovative stair box system, whereby a one floor lift of the stair tower is constructed in the plant. The stair risers are installed in the plant prior to shipping, and the entire assembly shipped to the job site. This process eliminates the need for bracing walls and the welding together of the individual parts. This innovative method produces a very high-quality, finished appearance of the stair or elevator exterior, and offers the additional advantage of rapid erection of the towers.

The Unistress Stairbox