A parametric study of the effect of geometric proportions on the permissible height of local masonry buildings fitted with anti-seismic sway-resisting frames at basement level

Abstract

Unreinforced masonry as a building material has been extensively used in the Maltese Islands, but unfortunately most of the local building stock is not designed to comply with the current seismic codes of practice. Of major concern is the behaviour of such structures during earthquakes, due to the limited resistance of masonry in sway and bending. The Maltese Islands have not recently experienced any significant seismic events, but damaging earthquakes have been recorded historically. The proliferation of the reinforced concrete and precast concrete industry, have allowed open plan basements to become increasingly popular, especially for car parking. As observed in previous research, the removal of all transverse walls within the basement results in a masonry structure that is prone to the soft storey effect. This dissertation continues to build upon the body of research work that deals with the replacement of the stiffness of walls with equivalent steel frames that allow the open plan basement layout. The parametric study in this research seeks to determine the safe height of buildings fitted with frames in the basement for six different residential building types. The masonry units used in this investigation are the Globigerina Limestone block and the hollow concrete block, while the mortars used range from M2 typically used in Malta to MS recommended by EC8. The effect of having the structures founded on a range of different types of geological formations, from rock to stiff clay is also investigated.