Kuarters staf S.M.K. Ranau dan kuarters pengawai Hospital Ranau telah mengalami kerosakan selepas gempa bumi Sabah berskala 6.0 pada 5 Jun 2015 dan telah dibaiki pada 2016. Akan tetapi, satu gempa bumi berskala 5.2 telah melanda Ranau, Sabah pada 8 Mac 2018 dan keadaan semasa kedua-dua bangunan ini masih tidak diketahui. Disertasi ini membentangkan hasil mengenai ciri dinamik kedua-dua bangunan ini yang mengalami peristiwa gempa bumi Sabah pada 2015 dan 2018 berdasarkan pemerhatian mikrogegaran pada Januari 2016, April 2017 and November 2018. Frekuensi modal dan bentuk ragam gegaran masing-masing ditentukan dengan kaedah Nakamura dan Penguraian Domain Masa (TDD). Disebabkan tiada kajian dilakukan ke atas ciri dinamik dua bangunan berkenaan sebelum gempa bumi pada 2015, analisis berkomputer telah dilakukan menggunakan ETABS berpandukan pelan arkitek dan pengukuran di tapak untuk mensimulasikan ciri dinamik dua bangunan berkenaan sebelum gempa bumi Sabah pada 2015. Hasil kajian menunjukkan bahawa frekuensi asas model bagi kuarters staf S.M.K. Ranau dan kuarters pegawai Hospital Ranau telah berkurang sebanyak 20 % selepas gempa bumi Sabah pada 2015. Pengurangan ini adalah ketara dan ia konsisten dengan kerosakan sederhana yang dialami oleh kedua-dua bangunan. Untuk kes selepas gempa bumi pada 2018, frekuensi asas kedua-dua bangunan telah menurun kurang daripada 2.5 %. Ini menunjukkan bahawa kedua-dua bangunan mungkin mengalami kerosakan yang sangat minor semasa gempa bumi. Prestasi seismik kuda-dua bangunan di bawah beban reka bentuk yang dinyatakan dalam Malaysia National Annex to MS EN 1998-1:2015 telah diperolehi melalui simulasi berangka dengan menggunakan analisis spectrum sambutan modal. Di bawah pecutan reka bentuk sebanyak 0.16 g, hanyutan antara tingkat maksimum berlaku di tingkat satu disebabkan kesan tingkat lembut. Hanyutan antara tingkat maksimum untuk kuarters staf S.M.K. Ranau telah melebihi had kerosakan yang dinyatakan dalam Eurocode 8. Keputusan juga menunjukkan jaket tiang yang digunakan terhadap kuarters staf S.M.K. Ranau semasa pembaikan pada 2016 telah meningkatkan frekuensi asas dan telah menggurangkan anjakan bangunan maksimum dan hanyutan antara tingkat maksimum, tetapi jaket tiang juga telah meningkatkan daya ricih tingkat dan momen terbalikkan maksimum di tingkat bawah.
_______________________________________________________________________________________________________
Staff quarters of S.M.K. Ranau and officer quarters of Hospital Ranau that were damaged during a Sabah earthquake with a magnitude of 6.0 on 5 June 2015 were repaired in 2016. However, an earthquake with a magnitude of 5.2 struck Ranau, Sabah again on 8 March 2018, thus it is unknown for the present condition of both buildings. This dissertation presents the results on dynamic characteristics of these buildings experiencing both Sabah earthquake events based on microtremor observations in January 2016, April 2017 and November 2018. The modal frequencies and vibration mode shapes of the buildings were determined by using the Nakamura method and Time Domain Decomposition method, respectively. Due to the absence of the study on dynamic characteristics of both buildings before 2015 Sabah earthquake, computational analyses were performed using ETABS based on the architectural plan and on-site measurement in order to simulate the building condition before the earthquake. The results show that the fundamental frequencies for staff quarters of S.M.K. Ranau and officer quarters of Hospital Ranau reduced up to 20 % after 2015 Sabah earthquake. This reduction is significant and consistent with moderate damages suffered by both buildings. For the case after 2018 Sabah earthquake, the fundamental frequencies of both buildings reduced less than 2.5 %. This implies that both buildings may suffered very minor damages during the earthquake. Seismic performances of both buildings under the design load stipulated in Malaysia National Annex to MS EN 1998-1:2015 were obtained through numerical simulation by using modal response spectrum analysis. Under the design acceleration of 0.16 g, the maximum interstorey drift occurs at the first floor due to soft storey effect. The maximum interstorey drift for the staff quarters of S.M.K. Ranau exceeded the damage limitation as specified in Eurocode 8. The results also showed that the column jacketing applied to staff quarters of S.M.K. Ranau during repair in 2016 increased the fundamental frequency and reduced the maximum storey displacement and interstorey drift, but this also increased the maximum storey shear force and overturning moment at the ground floor.
Dynamic characteristics and seismic performance of reinforced concrete buildings experiencing 5 june 2015 and 8 march 2018 sabah earthquakes / Ho Kar Meng