scholarly journals Rapid Repair of Seismically Vulnerable Bridge Columns Following Earthquake Induced Damage

2020 ◽  
Author(s):  
◽  
Gregory Norton
Keyword(s):  
Pacific Northwest ◽  
Cascadia Subduction Zone ◽  
Cyclic Performance ◽  
Rapid Repair ◽  
Steel Jacket ◽  
Simultaneous Impact ◽  
The Pacific ◽  
Damage States ◽  
Bridge Damage ◽  
Inelastic Strains

The Cascadia Subduction Zone (CSZ) earthquake has a high probability of occurrence within our lifetime, threatening bridges across the Pacific Northwest. Damage is expected to be geographically spread throughout the region and will have a nearly simultaneous impact on transportation through several important corridors. While bridge repair and replacement will ultimately be needed, priority will be placed on resuming mobility such that repairs will need to be implemented quickly. In an effort to anticipate this need, a repair method is being developed for rapid repair with the goal of achieving semi-permanent installation that also considers the different bridge damage states for future earthquakes. The proposed repair involves encasing the damaged column in a steel jacket which is then anchored to the foundation through easily replaceable ductile fuse hold-downs. The design objective is to isolate all inelastic strains to the hold-downs thus creating a low-damage solution. Full-scale cyclic tests were conducted to investigate the cyclic performance on substandard column-to-foundation specimens. The proposed repair was applied to the damaged column and the specimen was then re-tested using the cyclic loading that is representative of CSZ demands. The experiments validated the design goal of achieving restored or controlled strength, while also exhibiting no additional damage and self-centering behavior. The experiments have shown the potential of this methodology to rapidly repair earthquake damaged columns with a relatively generic approach.

2014 Update of the Pacific Northwest Portion of the U.S. National Seismic Hazard Maps

2015 ◽  
Vol 31 (1_suppl) ◽  
pp. S131-S148 ◽  
Author(s):  
Arthur Frankel ◽  
Rui Chen ◽  
Mark Petersen ◽  
Morgan Moschetti ◽  
Brian Sherrod
Keyword(s):  
Seismic Hazard ◽  
Pacific Northwest ◽  
Source Zone ◽  
Cascadia Subduction Zone ◽  
Maximum Magnitude ◽  
Hazard Maps ◽  
Seismic Hazard Maps ◽  
The Pacific ◽  
Eastern Edge ◽  
Western Portion

Several aspects of the earthquake characterization were changed for the Pacific Northwest portion of the 2014 update of the national seismic hazard maps, reflecting recent scientific findings. New logic trees were developed for the recurrence parameters of M8-9 earthquakes on the Cascadia subduction zone (CSZ) and for the eastern edge of their rupture zones. These logic trees reflect recent findings of additional M8 CSZ earthquakes using offshore deposits of turbidity flows and onshore tsunami deposits and subsidence. These M8 earthquakes each rupture a portion of the CSZ and occur in the time periods between M9 earthquakes that have an average recurrence interval of about 500 years. The maximum magnitude was increased for deep intraslab earthquakes. An areal source zone to account for the possibility of deep earthquakes under western Oregon was expanded. The western portion of the Tacoma fault was added to the hazard maps.

Post-earthquake Prioritization of Bridge Inspections

2007 ◽  
Vol 23 (1) ◽  
pp. 131-146 ◽  
Author(s):  
R. T. Ranf ◽  
M. O. Eberhard ◽  
S. Malone
Keyword(s):  
Ground Motion ◽  
Pacific Northwest ◽  
Epicentral Distance ◽  
Fragility Curves ◽  
Washington State ◽  
Motion Processing ◽  
The Pacific ◽  
Bridge Damage ◽  
Washington State Department ◽  
Prioritization Strategy

Bridge damage reports from the 2001 Nisqually earthquake were correlated with estimates of ground-motion intensity at each bridge site (obtained from ShakeMaps) and with bridge properties listed in the Washington State Bridge Inventory. Of the ground-motion parameters considered, the percentage of bridges damaged correlated best with the spectral acceleration at a period of 0.3 s. Bridges constructed before the 1940s, movable bridges, and older trusses were particularly vulnerable. These bridge types were underestimated by the HAZUS procedure, which categorizes movable bridges and older trusses as “other” bridges. An inspection prioritization strategy was developed that combines ShakeMaps, the bridge inventory and newly developed fragility curves. For the Nisqually earthquake, this prioritization strategy would have made it possible to identify 80% of the moderately damaged bridges by inspecting only 481 (14%) of the 3,407 bridges within the boundaries of the ShakeMap. To identify these bridges using a prioritization strategy based solely on epicentral distance, it would have been necessary to inspect 1,447 (42%) bridges. To help the Washington State Department of Transportation (WSDOT) rapidly identify damaged bridges, the prioritization procedure has been incorporated within the Pacific Northwest Seismic Network (PNSN) ground-motion processing and notification software.

scholarly journals Towards a Comparative Framework of Adaptive Planning and Anticipatory Action Regimes in Chile, Japan, and the US: An Exploration of Multiple Contexts Informing Tsunami Risk-Based Planning and Relocation

2020 ◽  
Vol 15 (7) ◽  
pp. 878-889
Author(s):  
Naoko Kuriyama ◽  
Elizabeth Maly ◽  
Jorge León ◽  
Daniel Abramson ◽  
Lan T. Nguyen ◽  
...  
Keyword(s):  
Pacific Northwest ◽  
Case Study Research ◽  
Coastal Areas ◽  
Washington State ◽  
Political Support ◽  
Cascadia Subduction Zone ◽  
Adaptive Planning ◽  
The Pacific ◽  
Tsunami Risk ◽  
Anticipatory Action

Coastal regions around the Pacific Ring of Fire share the risk of massive earthquakes and tsunamis. Along with their own political-economic, cultural and biophysical contexts, each region has their own history and experiences of tsunami disasters. Coastal areas of Washington State in the U.S. are currently at risk of experiencing a tsunami following a massive Magnitude 9 (M9) earthquake anticipated in the Cascadia Subduction Zone (CSZ). Looking ahead to consider adaptive planning in advance of a tsunami following this M9 event, this paper explores how lessons from recent megaquake- and tsunami-related experiences of risk-based planning and relocation in coastal areas of Japan and Chile could inform anticipatory action in coastal Washington State. Based on a comparison of earthquake and tsunami hazards, social factors, and the roles of government, this paper outlines a framework to compare policy contexts of tsunami risk-based planning and relocation in three Ring of Fire countries, including factors shaping the possible transfer of approaches between them. Findings suggest some aspects of comparative significance and commonalities shared across coastal communities in the three countries and at the same time highlight numerous differences in governance and policies related to planning and relocation. Although there are limitations to the transferability of lessons in disaster adaptive planning and anticipatory action from one national/regional context to another, we believe there is much more that Washington and the Pacific Northwest can learn from Japanese and Chilean experiences. In any context, risk reduction policies and actions need to garner political support in order to be implemented. Additional case study research and detailed analysis is still needed to understand specific lessons that may be applied to detailed risk-based planning and relocation programs across these different national contexts.

scholarly journals Tsunami Hydrodynamics in the Columbia River

2012 ◽  
Vol 7 (5) ◽  
pp. 604-608 ◽  
Author(s):  
Harry Yeh ◽  
◽  
Elena Tolkova ◽  
David Jay ◽  
Stefan Talke ◽  
...  
Keyword(s):  
Pacific Northwest ◽  
River Estuary ◽  
River Mouth ◽  
Columbia River ◽  
The United States ◽  
Large River ◽  
Cascadia Subduction Zone ◽  
The Pacific ◽  
The 2010 Chile Tsunami ◽  
Tohoku Tsunami

On 11 March 2011, the Tohoku Tsunami overtopped a weir and penetrated 49 km up the Kitakami River, the fourth largest river in Japan [1]. Similarly, the 2010 Chile tsunami propagated at least 15 km up the Maule River [2]. In the Pacific Northwest of the United States, large tsunamis have occurred along the Cascadia subduction zone, most recently the ‘orphan tsunami’ of 1700 (Atwater et al. [3]). The expected future occurrence of a Cascadia tsunami and its penetration into the Lower Columbia River became the subject of “the Workshop on Tsunami Hydrodynamics in a Large River” held in Corvallis, Oregon, 2011. We found that tsunami penetration into the Columbia River is quite different from a typical river. The tsunami enters the vast river estuary through the relatively narrow river mouth of the Columbia, which damps and diffuses its energy. The tsunami transforms into a long period, small amplitude wave that advances to Portland, 173 km from the ocean. Understanding this unique tsunami behavior is important for preparing a forthcoming Cascadia tsunami event.

Ground-Motion Attenuation Equations for Earthquakes on the Cascadia Subduction Zone

1991 ◽  
Vol 7 (2) ◽  
pp. 201-236 ◽  
Author(s):  
C. B. Crouse
Keyword(s):  
Data Base ◽  
Subduction Zone ◽  
Ground Motion ◽  
Pacific Northwest ◽  
Puget Sound ◽  
Response Spectra ◽  
Cascadia Subduction Zone ◽  
Regression Equations ◽  
Median Response ◽  
The Pacific

An extensive ground-motion data base was compiled for earthquakes occurring in subduction zones considered representative of the Cascadia subduction zone in the Pacific Northwest. The attenuation characteristics of horizontal peak ground accelerations (PGA) and 5 percent damped pseudovelocity (PSV) were studied for various subsets of the total data base. These data suggested that the PGA tend to saturate at small source-to-site distances and large magnitudes. When unprocessed data were added to the data base, the attenuation of PGA with distance was found to be greater than the attenuation observed for the processed data only, a result which was attributed to the selection of only the stronger motion records for processing. The results of the data analysis were used to establish the proper form of regression equations for estimating PGA and PSV at firm-soil sites in the Pacific Northwest. A total of 697 PGA components and 235 PSV components were selected for the regressions. The resulting equation for estimating PGA in gals was ln (PGA) = 6.36 + 1.76M − 2.73 ln (R + 1.58 exp (0.608M) + 0.00916h, σ=0.773 where M is moment magnitude, R is center-of-energy-release distance in km, h is focal depth in km, and σ is the standard error of ln (PGA). Although σ was relatively large, the residuals from the regressions appeared to decrease with increasing M and R. The results of the PSV regressions showed that the M coefficient and the coefficient of the f(R, M) attenuation term generally increased with period, which is consistent with regression results reported by others. The regression equations were reasonably accurate in predicting the response spectra of accelerograms recorded at Olympia and Seattle, Washington during the 1949 and 1965 Puget Sound earthquakes, but overestimated the spectra of the weaker motions recorded at Tacoma and Portland during the latter event. The median response spectra predicted by these equations for a Washington Coastal Ranges site were similar to the spectra computed by Heaton and Hartzell based on their simulations of ground motions from hypothetical giant earthquakes (M = 9.0 and 9.5) in the Pacific Northwest.

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