RESPONS PILAR JEMBATAN YANG DIDUKUNG OLEH FONDASI TIANG AKIBAT BEBAN GEMPA DENGAN MEMPERTIMBANGKAN INTERAKSI TANAH-STRUKTUR

• Main Author: M PURBA (NIM : 250 03 029); Pembimbing : I Wayan Sengara Ph.D, ALEKSANDER
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/19854
• Institution: Institut Teknologi Bandung

Recent earthqakes have resulted in critical damages to structures due to failure on both foundation and structural element that were not consistent with what expected using purely elastic techniques of analyses. When the seismic waves from earthquake reach the building, they will first shake structures then their foundation elements. For many years, researchers <br /> <br /> accomplished the problem by performing fix-based analysis for dynamic of structure and geotechnical earthquake engineering in separate way. However, this kind of calculation methods were not effectively proved especially when the rigid structure is sited on soft or <br /> <br /> stiff soil subjected to strong earthquake shaking. It is identified and considered that there is a interaction between the structure and soil which is known as soil-structure interaction (SSI) phenomena. The essence of this research is to study SSI comprehensively by investigating response of pile-supported bridge pier during earthquake excitation by using finite element method. The earthquake motion is derived from hazard spectra using Youngs and Sadigh attenuation fuctions according to appropriate earthquake mechanism. Synthetic earthquake motions are generated using proposed Norm Abrahamson spectral matching method that built in the EZFRISK software for in-depth seismic hazard analysis. The seismic SSI analysis is conducted by computer program PLAXIS Version 7.2 using equivalent 2-dimensional plain strain modeling. The analysis are performed in various peak base accelerations (PBA), site class, depths of base rock and heights of pier. The PBAs are varied to represent different earthquake zones, that are started from 0.1g up to 0.4g. The site classes are soft (SE), medium/stiff (SD) and hard soil (SC) in accordance with the UBC 1997 codes which is consistent with the Indonesian SNI 2002 codes. Depths of base rock are taken to be 30m and 80m while the height of pier are 10m and 20m. The free-field analysis results show that amplification factor are relatively consistent compared to both SNI and UBC codes. The response of pile-supported bridge pier are investigated in terms of maximum horizontal acceleration on the top of pier, differential horizontal displacement between top and bottom of pier and mobilized moment. Those SSI analysis results were compared to that of fix-based model.The analysis shows that fix-based system will give the conservative results compared to SSI model for structure is sited on hard soil. For the structure is sited on soft or stiff soil, the SSI effects must be considered <br /> <br /> especially for strong earthquake shaking. The result shows that the difference for maximum horizontal acceleration between fixed base system and SSI model is up to 30%.