Dynamic and seismic performance of old multi-tiered temples in Nepal

Old temples built in ancient time in Nepal are traditional and monumental structures with historic and archaeological importance. It is now an essential issue to evaluate their seismic safety for future earthquakes. Seismic evaluation method needs the fundamental dynamic properties of the temples. In this paper, dynamic properties of selected 10 typical multi-tiered temples are obtained by using the finite element method. Three of those temples are tested by ambient vibration methods under wind-induced excitation to obtain the real dynamic properties and validate the finite element models. Based on validated finite element model from the test, an empirical formula is proposed to estimate the natural period of vibration of Nepalese temples. Seismic capacity evaluation is then performed using the seismic coefficient method. To achieve a more realistic result, 3D dynamic analysis is carried out by the response spectrum method. Results show that the masonry temples in Nepal have fundamental time period less than 0.6 s. Damping ratio lies between 1% and 6%. The most crucial parts of Nepalese temples are the piers between the openings at the base level. Most of the failure modes are associated with tensile and compressive stresses.