Staggered truss system

The staggered truss system is a type of structural steel framing used in high-rise buildings. The system consists of a series of story-high trusses spanning the total width between two rows of exterior columns and arranged in a staggered pattern on adjacent column lines. William LeMessurier, the founder Cambridge, Massachusetts engineering firm LeMessurier Consultants has been credited in developing this award winning system as part of his research at the Massachusetts Institute of Technology.
History.
The staggered truss system came about due to sponsored research at Massachusetts Institute of Technology's Departments of Architecture and Civil Engineering in the 1960s by U.S. Steel. The research attempted to achieve the same floor-to-floor height with steel as you could with flat plate concrete. The system was presented at the 1966 AISC Conference (the predecessor to the current North American Steel Construction Conference). Additional benefits discovered were high resistance to wind loads and versatility of floor layout with large column-free areas.
It has been used with on a number of LeMessurier Consultants work in hotels including Lafayette Place Hotel in Boston and the Aladdin Hotel in Las Vegas. Other locations that use this system include the Resorts International
Hotel in Atlantic City, New Jersey, Embassy Suites hotel in New York City, Baruch College Academic Center in New York City, Trump Taj-Mahal in Atlantic City NJ, and the Renaissance Hotel in Nashville TN
Description.
The staggered truss system for steel framing is an efficient structural system for high-rise apartments, hotels, motels, dormitories, and hospitals. The arrangement of story-high
trusses in a staggered pattern at alternate column lines provide large column-free areas for room layouts. These column free areas can be utilized for ballrooms, concourses, and other large areas.
The staggered truss structural system consists of story-high steel trusses placed on alternating column lines on each floor so that the long axis of one truss is always between the trusses on the floor below. The system staggers trusses on a 12’ module, meaning that on any given floor the trusses were 24’ apart.
The interaction of the floors, trusses, and columns makes the structure perform as a single unit, thereby taking maximum advantage of the strength and rigidity of all the
components simultaneously. Each component performs its particular function, totally dependent upon the others for its performance.
The total frame behaves as a cantilever beam when subjected to lateral loads. All columns are placed on the exterior wall of the building and function as the flanges of the beam, while the trusses which span the total transverse width between columns function as the web of the cantilever beam.
While earlier staggered truss systems utilized channels for web diagonals and verticals, today most of the trusses are designed with hollow structural sections (HSS) for vertical and diagonal members because they are more structurally efficient and easier to fabricate. The trusses are fabricated with camber to compensate for dead load and are transported to the site, stored and then erected—generally in one piece.
Fabrication of this type of structure requires certified welders and overhead cranes capable of lifting 10 to 15-ton trusses and columns for projects up to 20 stories. Fabrication involves the following components: Columns, Spandrel Beams, Trusses, Secondary Columns & Beams and the Floor System.