Tubular Structural System Steel Frame Buildings Fabricated Steel Structure Construction For Office Building

The tube is a system where, to resist lateral loads (wind, seismic, impact), a building is designed to act like a hollow cylinder, cantilevered perpendicular to the ground. The tube system can be constructed using concrete, steel or a composite of both. In its simplest form, closely-spaced columns are tied together with deep spandrel beams through moment connections as part of the external perimeter of the building. The rigid frame that this assembly of columns and beams forms results in a dense and strong structural ‘tube’ around the exterior. Since lateral loads can be resisted by this stiff exterior framing, interior columns can be located at the core and are fewer in number. The interior can be simply framed for gravity loads and floor space is left free from columns. This type of structural system consists of a Framed tube, a Trussed tube, Tube-in-tube, Bundled tube and a Hybrid system.

Features of the tubular structural system:

The tubular structural system evolved from the concept of a rigid frame system which is a three-dimensional frame capable of resisting all lateral loads of the facade structure.

The system consists of an inner basic arrangement surrounded by outer columns,

with the outer perimeter columns close together and connected to each other,

using deep beams that form a rigid frame.

Thus this arrangement creates a dense and strong structural wall along the exterior of the building.

The outer frame is designed to be strong enough to withstand lateral loads on the building,

thus allowing the interior of the building to withstand gravitational loads.

The inner columns are few in number and are located around the main structure.

The base frame and surrounding frames are spanned by beams or struts,

so that these members help transfer gravitational loads into the structure.

This mechanism increases the effectiveness of the circumferential tube to resist overturning moments formed due to lateral loads.

The main types of tubular structural systems are:

Framed tube system

Trussed tube system

Tube in tube system

Bundled pipe system

Hybrid tube system