The Port de Port-au-Prince suffered extensive damage during the 12 January 2010, Mw 7.0 Haiti earthquake. The North Wharf, which collapsed completely, was a pile-supported marginal wharf constructed on un-engineered fill. The South Pier is a pile-supported structure that was built in about 1975. During the earthquake, the western-most section of the pier collapsed and the remaining portion was heavily damaged; approximately 40% of the piles were broken, 45% were moderately damaged, and 15% were slightly damaged.
The extensive damage to these facilities provides an important opportunity to validate numerical models of pile-supported port structures, particularly for severe damage states including collapse. However this opportunity requires that detailed data about the structural and geotechnical conditions that existed prior to the earthquake are quickly gathered. Because the existing data is very limited, additional data is needed to accurately characterize the conditions. Because of ongoing work to repair and replace the damaged facilities, relevant data are perishable.
The team will obtain structural and geotechnical data via several means, including (1) meeting with representatives from the Government of Haiti, Autorite Portuaire Nationale, and the U.S. Naval Facilities Engineering Command to discern the as-built structural and geotechnical conditions of the port facilities in as much detail as possible based on available documents and other types of information they may have available and (2) performing additional soil borings and cone penetration tests to evaluate the soil conditions at the port and obtaining concrete cores for strength testing.
The objective is to acquire sufficient data to allow these heavily damaged structures to be accurately modeled and used to advance our understanding of the seismic response of port structures. The intellectual merits of the study are: (1) validating numerical models of pile-supported structures, especially for the severe damage states (e.g., collapse) that occurred at the port and (2) collecting data on soils that liquefied during the earthquake and developed lateral spreads that will be useful in its own right as a liquefaction case history.
A broader impact of the study is that it will contribute to knowledge of the seismic design of port structures and the geotechnical and structural data acquired will assist with the effort to rebuild the heavily damaged Port de Port-au-Prince. Data from the study will be archived in the Network for Earthquake Engineering Simulation (NEES) Data Repository.
This award is co-funded by the NSF Office of International Science and Engineering (OISE).
The Port de Port-au-Prince suffered extensive damage during the 12 January 2010, Mw 7.0 Haiti earthquake. The North Wharf, which collapsed completely, was a pile-supported wharf constructed on un-engineered fill. The South Pier is a pile-supported structure that was built in about 1975. During the earthquake, the western-most section of the pier collapsed and the remaining portion was heavily damaged; approximately 40% of the piles were broken, 45% were moderately damaged, and 15% were slightly damaged. The extensive damage to these facilities provides an opportunity to investigate the underlying causes of the failures. This is important because many port structures in the U.S., particularly older ones, were constructed using similar methods. We performed six soil borings at the Port de Port-au-Prince to gather data on the soils supporting the wharf. Using the in situ testing results, we developed 12 new liquefaction case records involving relatively clean, calcareous sands, which are not well documented in the literature. In addition, we compared measured/estimated lateral spreading displacements to the displacements predicted by often-employed empirical and laboratory-based procedures. Although the field-observed liquefaction and lateral spread responses of these calcareous sands were compared with semi-empirical procedures that were developed primarily using field data of silica sands, the overall response of the artificial fills are reasonably consistent with predictions. The results of the soil borings and the analyses we performed clearly indicated that liquefaction of the soils contributed significantly to the failure of the structures and are particularly valuable because similar seismic behavior may be expected at many sea and river ports and other areas of reclaimed land in the U.S. and around the world that have hydraulically-placed calcareous sands.
