Seismic performance of critical infrastructures in port development
Seaports are vital to local and international transport networks and play a key role in a nation’s economic activity. In most countries, sea is the most common mode of international trade. In Indonesia, about 90 per cent of internationally traded goods are distributed by sea. Infrastructure damage to seaports can cause significant economic loss.
This project aimed to assess the response of critical port structures to earthquake forces. It focused on bridges connecting berths to the mainland. Issues associated with port development, including deep soil sediments and effects of natural environment on the structural conditions, were addressed. Field measurements using non-destructive testing equipment were proposed to determine the existing condition of structures. The method was used to assess two bridges in two ports (Terminal Peti Kemas and Pelabuhan Teluk Lamong) in Surabaya. The results were used as inputs to assess structural performance in an earthquake. The assessment showed that both structures were in good condition and existing maintenance and mitigation measures were effective.
The research has the potential to contribute to developing design guidelines and maintenance and mitigation strategies for ports in the region.
Poor foundation and backfill soil, common to waterfront environments, and liquefaction phenomena in loose saturated sand beneath port structures have been reported as common reasons for poor seismic performance in ports. Poor foundation soil was found to have caused damage to piles supporting the wharf structures in the Kobe earthquake and Haiti earthquake. Beside poor soil conditions, damage to port structures due to inadequate design and poor maintenance are equally common. When subjected to earthquakes, these structures can be more at risk of collapse. Inadequate shear reinforcement, improper detailing and corrosion of transverse ties contributed to the damage of piles supporting the port structures in Andaman Islands during the 2004 Sumatra earthquake.
Indonesia is one of the world’s most seismically active regions, with a tectonic boundary stretching from Sumatra to West Papua. Within the past decade, close to 20 earthquakes above magnitude 7 have occurred in the country, resulting in the seismic hazard map of Indonesia being updated to reflect an increase in seismic hazard values. However, there are currently no guidelines for seismic design of port structures in Indonesia.
In view of Indonesia’s high seismic activity and the importance of seaports, there is a clear need to assess the seismic performance of port structures. This project was able to predict seismic demands based on the seismic hazard and local site conditions, assessing the structural health of port structures using non-destructive techniques and conducting seismic vulnerability assessments based on structural health. Two ports in Surabaya, Indonesia, Terminal Peti Kemas and Pelabuhan Teluk Lamong, were used as case studies. Researchers assessed bridges connecting berths with the mainland.
The results of the assessment were used as inputs for seismic assessment of the structures. Probabilistic seismic hazard assessments have been conducted to establish seismic hazard values for regions in Indonesia. The assessment found an increase in seismic hazard for Surabaya and an increase in the uniform hazard spectra. The results indicate that structures could be subjected to much higher seismic forces than they were designed for.
A database of ground motions was developed based on established seismic hazard values, consisting of a combination of recorded and generated ground motion accelerograms. The ground motions were generated taking into account the effects of soil layers. Seismic vulnerability assessments were conducted based on non-linear time history analyses using the ground motion inputs. Fragility curves were constructed for different levels of structural degradation due to corrosion. It was found that taller piles are more vulnerable than shorter piles. It was also shown that corrosion can significantly increase structures’ vulnerability in an earthquake. The fragility curves indicate that the damage limit set for the bridges can be exceeded by 2500-year return period events for the most onerous case.
This research is potentially valuable in developing an innovative design guideline that will enhance the resilience of seaports to seismic hazards, as well as contributing to the development of innovative retrofitting and strengthening strategies for port structures.
People
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Professor Abbas Rajabifard
Director of the Centre for Disaster Management and Public Safety
The University of Melbourne -
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Dr Massoud Sofi
Research Fellow, Department of Infrastructure Engineering
The University of Melbourne -
Outputs
Journal articles
Sofi, M., Lumantarna, E., Mendis, P. A,, Duffield, C. & Rajabifard, A. (2017). Assessment of a pedestrian bridge dynamics using interferometric radar system IBIS-FS. Procedia Engineering, 188, 33-40. doi.org/10.1016/j.proeng.2017.04.454
Maizuar, M., Sofi, M., Lumantarna, E., Oktavianus, Y., Zhang, L., Duffield, C., Mendis, P., & Widyastuti, H. (2018). Dynamic behavior of indonesian bridges using interferometric radar technology, structural health assessment using non-destructive methods: Case studies of marine port and bridges in Surabaya. Special Issue: Structural Performance Assessment of Civil Infrastructure, Electronic Journal of Structural Engineering, 18(1), 23-29.
http://www.ejse.org/Archives/Fulltext/2018-1%20Sp/2018-1-3.pdf
Oktavianus, Y., Sofi, M., Lumantarna, E., Maizuar, M., Mendis, P. A., Duffield, C., & Widyastuti, H. (2018). Structural health assessment using non-destructive methods: Case studies of marine port and bridges in surabaya, Special Issue: Structural Performance Assessment of Civil Infrastructure, Electronic Journal of Structural Engineering, 18(1), 13-22.
Sofi, M., Lumantarna, E., Mendis, P., Duffield, C., Rajabifard, A. Assessment of a pedestrian bridge dynamics using interferometric radar system IBIS-FS. 6th Asia-Pacific Workshop on Structural Health Monitoring (APWSHM). Elsevier BV. 2017, 188. Editors: Chiu W.K., Galea S., Mita A., Takeda, N. DOI: 10.1016/j.proeng.2017.04.454
Hui, F. K. P., Duffield, C., Wilson, S. (2018). Proceedings of the Port Competitiveness and Financing Research Workshop, Proceedings of the Port Competitiveness and Financing Research Workshop, 164
http://hdl.handle.net/11343/210542
Presentations
6th Asia-Pacific Workshop on Structural Health Monitoring, 7-9 December 2016
Competitiveness and Financing Research Workshop 4-6 April 2018
AIC Infrastructure Cluster Conference 8-9 May 2018