A methodology for assessing the load capacity of cantilevered stone stairs

Abstract

Cantilevered stone stairs were widely constructed from the 17th to the 20th century. Thousands of these stairs were built in Ireland and across Europe during this period and they have proven to be very robust. However, the recent collapse of a flight of cantilevered stone stairs in the Natural History Museum in Dublin shows that they can fail. The majority of cantilevered stone stairs do not cantilever; each tread in a cantilevered stone stairs transfers the load applied to it to the wall support and to the tread below. The predominant resulting force developed within the tread is a torque. Cantilevered stone stairs are highly statically indeterminate which complicates their analysis. In addition, the stone used in their construction is a natural and often highly variable material.