SPACE FRAME

REASONS WHY THE SYSTEM OF SPACE FRAME ARE CONNECTED WITH BOLT AND NOT WELDED

Frames are the assembly of members joined together, space frame  can be defined as a frame work of element, which forms a rigid or stable structure made upon a triangles that are three dimensional in geometry, making it geometrically stiff and rigid. the primary objectives of a space frame emanate from the need for flexibility in design, for a space frame to fully serve it objectives of flexibility it must exhibit the ability to be assembled and disassembled, this ability can only be achieve through the use of bolt connections, in situation where the design assemblage cannot be professionally done a bolted connection can be suggested, a joint restrain or take away from two members of a frame some degree of freedom which one member would have relative to the other if they were not connected.

Space frame are needed basically for their ability to span a longer distance, while a long span member used to cover a large area experience flexural moment that is excessive, so a bolt connection is used for long span members to allow flexure between member and tolerance.

A space frame has an inherent rigidity of triangular links, with members under the influence of flexing load, which need to be transmitted as tension and compression along the length of each strut to the joint, these tensional loads effect can be reduce by tightening the but/nut to develop a preload, thereby reducing the fatigue due to cyclic loading, this cannot be done by welding instead welding will pull through a hole when loaded in tension.

 Bolt connections does not change or influence the condition of the parent material, bolt can be installed without piercing through the whole of the member that is  a blind hole or does not go all the way through the material, bolt connection does not take much time  and do not need special skills to assemble,

Bolt connections are of a good quality thus makes a better joint connection, they makes use of threads which can be controlled, although the strength of a bolt connection is lower to that of a welded connection but it  strength can be increased through tightening and through the choice of member sections

Space frame are transported over a long distance since it is prefabricated, therefore connectors such as bolt is easier to transport and installed than machines meant for welding requiring professionals that can operate them

Space frame are lighter making them useful in earth-quake areas, to maximise their functions during earth movement, it requires some degree of freedom that can only be achieved by using a bolt connection which will eventually allow flexure. space frame can be used as a transformable structure that is can be redesigned for another use there by for the fulfilment of that objective it has to make use of bolt connections

Weld connections are very tedious such that it is impossible to tell if the weld has a procure examination or not, it requires a sonic or X-ray equipment in other to detect accuracy. Weld connections needs a dry and clean metal, this will be difficult in areas with wet climate, while site bolting eliminate fire risk ,and less noise to neighbouring environment. Bolt connector can be designed in such a way that it would with stand double shear failure from two members. Forces within the connection depends on of the both the capacity of the welds, bolts etc and on the relative ductility of the connected parts. When proportioning connections the engineer should always consider the basic requirements such as the stiffness/flexibility of the connection, strength and the required rotational capacity. The movements of a structure are not in themselves detrimental; the problems arise where movements are restrained, either by the way in which the structure is connected to the ground, or by surrounding elements such as claddings, adjacent buildings, or other fixed or more rigid items. If provision is not made for such movements and associated forces it is possible that they will lead to, or contribute towards, deterioration in one or more elements.