Bundled tube

structural system

ByUmer

Farooq

Presentation on

One of the most efficient structural systems against heavy wind loads is the bundled tube structural system

The first person to implement the bundled tube structural system was Fazlur Rahman Khan from Dhaka, Bangladesh with the design of the DeWitt-Chestnut Apartments in Chicago, Illinois.

Bundled tube structural system

The landmark and iconic building that uses the bundled tube structural system is the Willis Tower (formerly known as the Sears Tower)

Fazlur Rahman Khan

A bundled tube typically consists of a number of individual tubes interconnected to form a multicell tube, in which the frames in the lateral load direction resist the shears, while the flange frames carry most of the overturning moments.

A Bundled Tube Structure

No interior columns 110 stories 1,469′-0″ in height Tallest building until 1996 Each structural tube = 75′-0″ x 75′-0″ Completed in 1974

The Willis Tower in Chicago used this design, employing nine tubes of varying height to achieve its distinct appearance. It consists of exterior framed tube stiffened by interior frames to reduce the effect of shear lag in the exterior columns.

Details on the Sears Tower:

Bundled Tube Structural System and how it effects the floor plan

Advantages of Bundled tube system

Sufficient lateral stiffness Building acts as a unified system of stiffened tubes Aesthetically appealing The interaction between the individual tubes and the

belt trusses at mechanical levels allows the building to attain its extreme height

These trusses take the gravity loads from above and redistribute them evenly onto the tubes below

The bundle tube design was not only highly efficient in economic terms, but it was also "innovative in its potential for versatile formulation of architectural space.

Efficient towers no longer had to be box-like; the tube-units could take on various shapes and could be bundled together in different sorts of groupings.

The bundled tube structure meant that "buildings no longer need be boxlike in appearance: they could become sculpture

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