Size of the site and access may also influence the size of prefabricated members. The most important technical decision which must be taken when a high rise structure is designed, is its resistance to lateral loads. There are several alternative methods of structural steelwork framing, their suitability depends largely on the magnitude of the lateral loads, which are in turn related to the height and location of the building. Rigid frame construction - the connections between columns and beams are capable of sustaining bending moment. Thus the structure is stiff enough to resist excessive lateral deflection.
Columns are stronger and larger than in other systems, beams are lighter and have a reduced depth.
The frame carries the loads and therefore the services core containing lifts and staircases can be loaded anywhere within the building. Wind loads are transferred from walls to this core by floors. The structural frame thus carries gravity loadings only with simple sections and less expensive connections between members. Shear wall system - this system relies on an arrangement of rigid, vertical walls to resist the lateral loading. The floors act as continuous diaphragms in transmitting the lateral loads from the facade to the shear walls.