STONE MASONRY CONSTRUCTION

Stone masonry is a traditional form of construction practiced for centuries in the regions

where stone is locally available. It is still found in old historic centers, often in buildings

of cultural and historical significance, and in developing countries where it represents

affordable and cost-effective housing construction. This construction type is present in

earthquake-prone regions of the world, such as Mediterranean Europe and North Africa,

the Middle East, India, Nepal, and other parts of Asia.

Houses of this construction type are found both in urban and rural areas. There are broad variations in their shape and the number of stories. Houses in rural areas are generally smaller in size and have smaller openings since they are typically used by a single family.

Buildings in urban areas are often of mixed use, that is, with a commercial ground floor

and multifamily residential area above. Houses in the countryside are built as stand-alone structures, while the neighboring houses in old town centers often share a common wall.

Rural one-story stone masonry houses with timber frames and thick flat roofs for thermal insulation (“khan”) are widely spread throughout India. In the mountainous and hilly regions of Nepal there are two types of stone masonry houses: a traditional oval shaped house and a rectangular-shaped house, both typically two stories high. In hilly

Mediterranean countries the number of stories varies between two in rural areas and

five in towns. Typically, stone masonry houses are used by the lower and middle classes, however in historical urban centers they are often inhabited by the upper classes. Urban masonry buildings are characterized with several internal renovations and updates in the course of their useful life.

The houses are built by local builders or by owners themselves, without any formal

training. The quality of construction in urban areas is generally superior to that found in

rural areas.

The most important factors affecting the seismic performance of these buildings are:

 The strength of the stone and mortar

 The quality of construction

 The density and distribution of structural walls

 Wall intersections and floor/roof-wall connections

Stone masonry construction generally shows very poor seismic performance. Poor quality of mortar is the main reason for the low tensile strength of rubble stone masonry. Timber floor and roof structures are usually not heavy and therefore do not induce large seismic forces. However, typical timber floor structures are made of timber joists that are not properly connected to structural walls. These structures are rather flexible and are not able to act as rigid diaphragms. Due to their large thickness, stone masonry walls are rather heavy and induce significant seismic forces.