Fragility analysis of pile-supported wharves in the Cascadia Subduction Zone
| dc.contributor.author | Sepehri Sefidab, Ahmad | |
| dc.contributor.supervisor | Zhou, Lina | |
| dc.contributor.supervisor | Lin, Cheng | |
| dc.date.accessioned | 2021-05-27T22:19:58Z | |
| dc.date.copyright | 2021 | en_US |
| dc.date.issued | 2021-05-27 | |
| dc.degree.department | Department of Civil Engineering | |
| dc.degree.level | Master of Applied Science M.A.Sc. | en_US |
| dc.description.abstract | In this study, incremental dynamic analyses were carried out to investigate the damage risk of a typical pile-supported wharf under three types of ground motions that may happen in the Cascadia Subduction Zone, i.e., the shallow crustal, in-slab, and interface earthquakes. Firstly, a prestressed concrete pile-supported wharf located in Vancouver, site class C, was designed according to the displacement-based design approach recommended by ASCE 61 (2014). Next, a two-dimensional nonlinear numerical model of the wharf was created in OpenSees software. The fiber section method was used in this research to simulate the plastic performance of piles. Soil-structure interaction was implemented using three types of nonlinear springs available in the OpenSees library. The nonlinear modeling method of pile-deck connections was validated with experimental results from past research. For nonlinear dynamic analyses, eleven ground motions (two horizontal components per motion) were selected for each type of earthquake following a series of selection criteria. After that, incremental dynamic analyses (IDA) were performed that include thousands of nonlinear calculations in total. Three damage states represented by the strain limit of materials were defined based on criteria proposed in PIANC (2001). Finally, three sets of fragility curves were developed for each type of ground motion as a cumulative distribution function of spectral accelerations, representing the probability of occurrence of three different damage states: serviceable damage, repairable damage, and severe damage. Results show the importance of considering in-slab and shallow crustal events for wharf structures located in the Cascadia Subduction Zone. For the hazard level with an exceedance of 2% in 50 years, the risk of serviceable damage on pile-supported wharves located in Vancouver under all three types of earthquakes is fairly high, while the risk of repairable and severe damage is acceptable. In general, interface earthquakes are not the significant earthquakes for wharves located in Vancouver (or lower mainland). This is due to the large distance of Vancouver to the rupture area which damps high-frequency motions (shorter periods), and makes short-period structures, such as wharves analyzed in this project, less vulnerable to these earthquakes. Based on deaggregated hazards, for the first two damage states, in-slab earthquakes can be considered as the dominant risk for wharves in the lower mainland, while shallow crustal earthquakes are more significant in terms of severe damage. Also, it was found that pulse-like shallow crustal earthquakes should be considered for port structures located in the Cascadia Subduction Zone, as they can have a severe effect on the seismic performance of port structures and may cause considerable damage to them. This is in response to the uncertainty of the existence of any crustal faults underneath or close to Metro Vancouver | en_US |
| dc.description.scholarlevel | Graduate | en_US |
| dc.identifier.uri | http://hdl.handle.net/1828/13000 | |
| dc.language | English | eng |
| dc.language.iso | en | en_US |
| dc.rights | Available to the World Wide Web | en_US |
| dc.subject | Cascadia Subduction zone | en_US |
| dc.subject | Earthquake | en_US |
| dc.subject | fragility analysis | en_US |
| dc.subject | Incremental dynamic analysis | en_US |
| dc.subject | Wharf | en_US |
| dc.title | Fragility analysis of pile-supported wharves in the Cascadia Subduction Zone | en_US |
| dc.type | Thesis | en_US |