Modular design for high-rise buildings

Modular construction is widely used for residential buildings of four to eight storeys and there is pressure to extend this relatively new form of construction to 12 storeys or more. This paper reviews recent modular technologies, and also presents load tests and the analysis of light steel modular walls in compression. A design method for high-rise modular applications is presented taking account of second-order effects and installation tolerances. For the modular walls tested, it was found that the plasterboard and external sheathing boards effectively prevent minor axis buckling of the C sections, so that failure occurred either by major axis buckling or local crushing of the section. In all cases, the results of the tests on 75 mm and 100 mm deep × 1·6 mm thick C sections exceeded the design resistance to BS 5950-5 by 10 to 40%. However, an eccentricity of 20 mm in load application reduced the failure load by 18 to 36% owing to local crushing of the C section. Tension tests on typical connections between the modules and corridors gave a failure load of 40 kN, which is adequate to transfer wind forces to a braced core and also to provide tying action in the event of loss of support to one corner of a module. Corner posts provide enhanced compression resistance but their buckling resistance is dependent on the sway stiffness of the wall panel. It is also shown that the notional horizontal force approach for steel structures presented in BS 5950-1 should be increased for modular construction.