Model Verification of Thai Historic Masonry Monuments

Abstract

This paper presents the result of research efforts to better understand engineering behavior of historic masonry monuments at the Ayutthaya UNESCO World Heritage site in Thailand. Two dominant styles of Thai historic masonry monuments, bell-shaped and corn-shaped, were investigated. In the first stage of modeling, both styles of monuments were analyzed under their own weight using homogenized material properties. In the second stage, frequency analyses were performed to identify their vibration properties and dynamic response ranges. Finally, in situ ambient frequencies of two monuments were measured and compared to analytical frequencies. It was found that although the principal compressive stresses for both styles of monument were within safe limits, the safety factor against crushing around the entrances of the corn-shaped monument was found to be low. Moreover, there exist unexpected tensile stress fields around the upper middle part of both styles that might have been the cause of cracks commonly found. More consistent dynamic characteristics, such as frequency, were found when the underlying clayey layers were incorporated in the model. With critical stress zones identified, future strengthening programs for these monuments could be more precisely designed. Tension cracks and subsequent damages could be prevented. The soil-structure interaction model proposed will ensure that no threatening modes of failure such as torsion will be overlooked.