Tahap kerosakan bangunan yang disebabkan oleh Gempa Bumi Sabah 2015 masih tidak diketahui walaupun terdapat pelbagai bangunan telah dirosakkan. Disertasi ini membincangkan keputusan yang berkaitan dengan sifat dinamik bangunan konkrit bertetulang yang dirosakkan semasa Gempa Bumi Sabah 2015. Mikrogegaran telah diperhatikan di kuarter guru S.M.K. Ranau dan kuarter pegawai Hospital Ranau selepas kejadian gempa bumi. Bangunan yang telah dipilih mempunyai dua blok dengan ciri-ciri yang sama iaitu bangunan lembut tingkat. Frekuensi tabii akan ditentukan dengan menggunakan kaedah H/V manakala bentuk gegaran ragam akan ditentukan oleh kaedah Penguraian Domain Masa (TDD). Frekuensi tabii di paksi kritikal blok A kuarter guru menurun sebanyak 16.4 % berbanding dengan blok B. Frekuensi tabii di paksi kritikal blok B kuarter pegawai berkurang sebanyak 8.4 % berbanding dengan blok A. Selepas itu, model bangunan berpandukan pelan arkitek dan pengukuran semasa lawatan tapak telah dianalisa menggunakan ETABS untuk mendapat ciri dinamik bangunan dalam keadaan sebelum kejadian gempa bumi. Frekuensi tabii di paksi kritikal blok A kuarter guru menurun sebanyak 19.7 % manakala frekuensi tabii di paksi kritikal blok B kuarter pegawai menurun sebanyak 14 % selepas kejadian gempa bumi. Pekali kekukuhan kepada blok A kuarter guru berkurang sebanyak 37.8 % di paksi kritikal. Tambahan pula, pekali kekukuhan berkurang sebanyak 25.2 % di paksi kritikal blok B kuarter pegawai. Blok A kuarter guru dan blok B kuarter pegawai mempunyai frekuensi tabii dan pekali kekukuhan yang lebih rendah dan keputusan kajian adalah konsisten dengan tahap kerosakan yang diperhatikan semasa lawatan tapak.
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Various buildings were damaged in the 2015 Sabah Earthquake. However, the degree of structural damage in the 2015 Sabah Earthquake is unknown. This dissertation presents the results of field survey on dynamic characteristics of reinforced concrete (RC) buildings damaged by the 2015 Sabah Earthquake. Microtremor was observed at teacher quarters of S.M.K. Ranau and officer quarters of Hospital Ranau after the earthquake event. Each selected building consists of two identical blocks with similar soft-storey structural form. The predominant frequencies of the damaged buildings were determined by using the H/V method while the vibration mode shapes were estimated by using the Time Domain Decomposition (TDD) method. The predominant frequency in critical axis of block A of teacher quarters reduces up to 16.4 % compared to block B. Besides, the predominant frequency in critical axis of block B of officer quarters reduces up to 8.4 % compared to block A. Furthermore, numerical simulation were performed by using ETABS on the damaged buildings based on the architectural plan and field measurement data to obtain the dynamic characteristics of the building before the earthquake event. The results show that the predominant frequency in critical axis of block A of teacher quarters reduces up to 19.7 % compared to the undamaged state. On the other hand, the predominant frequency in critical axis of block B of officer quarters reduces up to 14 %. Moreover, the stiffness reduces up to 37.8 % in critical axis for block A of teacher quarters and the stiffness reduces up to 25.2 % in critical axis for block B of officer quarters. The results are consistent with the observed building performance in which the building suffered in severe damage (block A of teacher quarters and block B of officer quarters) have lower predominant frequency and higher stiffness reduction percentage.
Determination of dynamic characteristics of damaged buildings in the 2015 Sabah earthquake using microtremor observation / Lim Yang Soh