Study on the cracks developed in Dematamal Viharaya, Uva Province Sri Lanka

Abstract

Stupas of Sri Lanka stand as proud examples for the engineering Excellence of ancient Sri Lanka. Dematamal Viharaya at Butthala is one of the oldest Stupas in Sri Lanka built in the 2nd Century BC. It is a, 19m tall non-plastered brick structure. This Stupa has developed since 1998. Cracks have initiated from the Pesawalalu and propagate to the top of the Dome. The width of these cracks varies from 0.2mm to 0.5mm. The research covered in this report is aimed at the identification of the causes for the cracks and to propose corrective actions. A comprehensive study was carried out to identify the possible causes for the cracks which may be due to self weight and shape of the stupa, expansive nature of soil, arch action induced due to separation of old and modern masonry. Experiments were done to assess the expansive nature of the soil and A Finite element analysis was carried out using the Finite element software SAP2000. The results revealed that the possible cause can be the arch action induced due to separation of old and modern masonry. Increasing the bearing of the new brick work at the base and the installation of a tie beam around the pesawalalu are the two corrective actions suggested in this report.