Learning from Earthquakes: First person reports


Effects of the 2011 Tohoku Japan Earthquake on Steel Structures

August 3, 2011 by

US Team

James M. Ricles, Professor, Lehigh University, Bethlehem, PA, USA (Group Leader)

Dimitrios G. Lignos, Assistant Professor, McGill University, Montreal, Canada

Jay Love, Degenkolb Engineers, San Francisco, CA, USA

Japan Team

Mitsumasa Midorikawa, Professor, Hokkaido University, Japan

Taichiro Okazaki, Associate Professor, Hokkaido University, Japan

EERI Steel Structures Reconnaissance Group (from left to right: Prof. Taichiro Okazaki, Prof. Mitsumasa Midorikawa, Mr. Jay Love, Prof. Dimitrios Lignos, Prof. James Ricles)

Day 1 (June 2, 2011)

After arriving in Tokyo during the evening we had a briefing at the AIJ headquarters by Prof. Midorikawa and Prof. Okazaki. We were informed about the areas of reconnaissance as part of our trip and the major earthquake and tsunami damage on steel structures in the Sendai area. Our reconnaissance effort focused around the following areas: Tohoku University, Oroshimachi and two of the main fishing ports the Ishinomaki and Onagawa that were affected by the tsunami during the 2011 Tohoku earthquake in Japan.

Day 2 (June 3, 2011)

After taking the Shinkansen from Tokyo we arrived to Sendai around 11:00am. Our first stop was in Tohoku University. Dr. Mosato Motosaka, Professor of Earthquake Engineering and Structural Dynamics at Tohoku University was our host. We visited several buildings located on campus that were damaged during the earthquake. The main observations from steel, composite and reinforced concrete buildings retrofitted with steel braces are summarized as follows:

Architecture Building: This is a 9-story steel-reinforced concrete building with three podium levels (see Figure 1). This building was damaged during the 1978 Miyaki-ken Oki earthquake. After the 2003 earthquake in the same region the building was retrofitted with steel braces (see Figure 2). After the 2008 earthquake the university installed a long time monitoring system to measure changes in stiffness over time. Prior to the 2011 earthquake, this building had a predominant period of about 0.6sec. The earthquake damage was concentrated at the vertical boundary elements of the transverse concrete shear walls at the transition floor from the tower to the podium level.

Figure 1. Architecture building

Figure 2. Steel braces as part of the 2003 seismic retrofit of the architecture building in Tohoku University

Figure 3. Seismic retrofit of the exterior columns of the architecture building

The period elongation of the building during the 2011 earthquake was about 1.3sec. The building was recently retrofitted with longitudinal concrete walls at the corners (see Figure 3).

 

 

 

 

 

 

Applied Chemisty and Chemical Engineering Building: This is a reinforced concrete construction, which was retrofitted with steel braces in the past as shown in Figure 4. This building had no indication of damage after the 2011 earthquake.

Figure 4. Applied chemistry and chemical engineering building

New Civil Engineering Building: The 13-story building, which is shown in Figure 5 consists of steel MRFs. Its steel columns are encased with reinforced concrete (see Figure 6). This building performed very well during the March 2011 earthquake. It should be pointed out that the building is equipped with oil dampers. One of these dampers is shown in Figure 7. The maximum absolute acceleration at the roof of the building was about 1g during the 2011 earthquake. However, only non-structural damage was reported in the building.

Figure 5. New Civil Engineering (CEE) Building

Figure 6. Steel column encased with reinforced concrete

Figure 7. Oil damper installed in the CEE building

 

 

 

 

 

 

 

During our route to the coast we visited a 13-story steel encased reinforced concrete building (SRC) at Sunny Heights. This building was designed in 1976 with pile foundation due to bad soil conditions in this area. The primary structural system consisted of composite moment resisting frames. During the main event (Mw=9.0) the residual roof displacement was 70cm (~1.3% rad) and after the main aftershort of April 7th (Mw=7.4) the residual roof displacement of about 2% rad (see Figure 8). The bad performance of the foundation (soil liquefaction as shown in Figure 9) “helped” the building not to collapse. The building had several shear cracks in non-structural components as shown in Figure 10. Note that opposite to this structure there was a 7-story light-gauged pre-fabricated building with reinforced concrete footing (i.e. no piles) that performed very well during the earthquake.

Figure 8. 13-story SRC residential building (residual roof drift of about 2%)

Figure 9. Soil foundation problems due to liquefaction (13-story SRC condominium)

Figure 10. Shear cracks to non-structural components of the 13-story SRC building

 

 

 

 

 

 

 

 

Our next stop was in the coast. There were several steel buildings with their primary lateral system being a steel MRF that survived the earthquake followed by the Tsunami. The average height of the steel buildings in this area ranges from 2 to 4-stories. Typical failure modes in industrial buildings such as the one shown in Figure 11 included exposed column base failure and twisting of deeper steel columns due to ramming (Figure 12). Note that in this area there are several steel buildings with cover plate connections and W shape columns. This indicates old japanese steel construction since the modern ones are typically built with hollow square sections (HSS).

Figure 11. Steel industrial building partially collapsed due to ramming

Figure 12. Twisting of steel beams and columns due to ramming

Figure 13. Horizontal X-bracing to guarantee diaphragm action

Another characteristic of the steel buildings that survived the Tsunami is the fact that the floor diaphragm action is guaranteed with horizontal X-bracing (see Figure 13).

 

 

 

 

 

 

2-story industrial building: The building shown in Figure 14 had a residual drift of about 4% in the East-West (EW) loading direction. In the same direction, there was indication of earthquake damage due to flange local buckling of the steel beams near the beam-to-column connections at top and bottom location as shown in Figure 15. This building also experienced panel zone inelastic deformation as shown in Figure 16. In the other loading direction (North-South) the primary lateral system was a braced frame. Net section fractures were observed in this case (see Figure 17). The residual deformation of the steel building in the NS direction was about 1.25%.

Figure 14. 2-story steel industrial building with a complete 2 story collapse mechanism

Figure 15. Local buckling of the bottom flange of the first floor steel beam of the 2-story steel industrial building

Figure 16. Panel zone shear distortion (2-story steel industrial building)

Figure 17. Steel X-brace in the NS loading direction of the 2-story steel industrial building

 

 

 

 

 

 

 

 

At the end of the day we joined Prof. Kasai’s group and Prof. Motosaka gave us a briefing of the earthquake related damage in Tohoku University and Oroshimachi area during the 2011 Off Pacific Coast Tohoku earthquake.

Day 3 (June 4, 2011)

During the third day we visited the Onagawa fishing port , which is shown in Figure 18. This area was primarily damaged from the Tsunami that followed the earthquake. We visited several industrial steel buildings located in the area. The steel buildings in this area range from 2 to 5 stories.

Figure 18. Onagawa fishing port

2-story industrial steel building: The building shown in Figure 19 consists of a 1-bay steel moment frame in the NS loading direction with cover plate moment connections and a 4-bay braced frame in the EW loading direction. Due to wave pressure a second story sway mechanism was developed due to weak axis column bending as shown in Figure 20. This resulted to excessive local buckling at the bottom of these columns as shown in Figure 21. When the steel braces of the second story fractured the sway mechanism was developed.

Figure 19. 2-story steel building with 2nd story collapse mechanism due to lateral water pressure

Figure 20. 2nd story column weak axis bending due to lateral water pressure

Figure 21. Local buckling of the steel columns at the 2nd story of the steel structure

 

 

 

 

 

 

 

 

3-story restaurant building: The 1×3 bay steel building shown in Figure 22 has steel moment resisting frames as the primary lateral resisting system in both loading directions. Due to the Tsunami wave the building developed a 3-story sway mechanism shown in the same figure and had a residual deformation of about 6% in the first story. This building was designed before 1981 since its beam-to-column connections include fins that were welded in the field. All the connections of the 3-bay steel MRFs fractured (see Figures 23, 24). Base plate uplift was in the order of 4cm as shown in Figure 25.

Figure 22. 3-story steel moment resisting frame with a 3-story complete collapse mechanism

Figure 23. Weld fractures at the interior fin beam-to-column connection of the 3-story restaurant building

Figure 24. Weld fractures at the exterior fin beam-to-column connection of the 3-story restaurant building

Figure 25. Base plate uplift (3-story restaurant building)

 

 

 

 

 

 

 

 

3-story steel industrial building: The building shown in Figure 26 was a 4×4 bay 3-story steel building with steel MRFs in both loading directions. The building had 30x30cm tubular columns and modern japanese connections (see Figure 27) therefore the design is post 1981. The diaphragm action was guaranteed through horizontal x-bracing as shown in Figure 28. Excluding the exterior cladding the main structural system performed well during the earthquake and tsunami. In summary, steel buildings that were designed based on older japanese seismic provisions around the area and survived the tsunami had minor damage due to uplift of their base plates.

Figure 26. 3-story steel industrial building that survived the tsunami in the Onagawa area

Figure 27. Typical beam-to-column connection of a modern japanese steel construction

Figure 28. Horizontal x-bracing per floor (3-story steel industrial building)

 

 

 

 

 

 

 

 

Toppled Buildings: There were at least 5 buildings (both steel and RC buildings) with pile foundations that toppled over due to the water pressure from the tsunami. An example of those buildings is shown in Figure 29 that shows a 3-story steel building. The pile foundations of the same building were damaged due to overturning as shown in Figure 30. At least 4 more buildings toppled over due to the wave pressure (see Figures 31).

 

Figure 29. 3-story steel building with pile foundation that toppled over due to the water pressure

Figure 30. Foundation of 3-story steel building (piles failed in tension)

Figure 31. Toppled reinforced concrete building (Onagawa port)

 

 

 

 

 

 

 

 

After leaving the Onagawa port, on our way to the fishing market we visited a school gymnasium designed in 1970s (see Figure 32). This building consisted of steel braces (angles) in EW loading direction. Some of these braces buckled during the earthquake (see Figure 33). The roof of the building had sag rods. Almost 90% of these rods were damaged due to bold fracture in shear (see Figure 34).

Figure 32. School gymnasium with steel braces designed in 1970s

Figure 33. Buckled X-brace of the steel gymnasium

Figure 34. Damaged sag rods at the roof of the school gymnasium

 

 

 

 

 

 

 

 

In the fishing market several steel industrial buildings were damaged due to the tsunami. When we arrived to the fishing market there was a street construction going on since part of the fishing market was sunk about 70cm due to the earthquake.

The front entrance (facing the sea) of the 1-story steel industrial building shown in Figure 35 was not damaged at all compared to the back portion, which is shown in the same figure. The reason was that the water came inside the building from the bottom and the water pressure destroyed the concrete floor (see Figure 36). Several column base rods of the back entrance fractured and steel columns failed due to lateral torsional buckling as shown in Figure 37.

Figure 35. One story steel industrial building in the fishing market

 

Figure 36. Cracked concrete slab from the water pressure

Figure 37. Lateral torsional buckling of a steel column due to impact

 

 

 

 

 

 

 

 

Several steel buildings that did not collapse due to the tsunami had excessive damage at exposed base plates. Typical failure modes included rod fracture due to tension and uplift of the base plate. Figures 38, 39 and 40 are representative examples that illustrate these failure modes.

Figure 38. Column base rod fracture due to overturning

Figure 39. Column base uplift

Figure 40. Column base uplift

 

 

 

 

 

 

 

Around the fishing market, several old steel industrial buildings with heavy equipment consisted of diagonal angle steel braces. Net section fracture occurred in most of these braces as shown in Figure 41.

Figure 41. Net section fracture of a steel brace (steel industrial buildings)

On our way back to the hotel we crossed a heavy industrial zone close to the fishing market. One of the steel buildings that was damaged consisted of 12 spans in the longitudinal loading direction but 2 of those were missing due to ramming (see Figure 42). The building had tie rods as vertical bracing that failed at the base due to bold shear failure (see Figure 43). The residual drift of this building in the longitudinal loading direction was about 0.23% rad. Uplift was also observed in several base plates of the building. Based on observations at the roof something pushed the roof girder in the longitudinal loading direction and caused the residual deformation discussed earlier. Other industrial buildings in the area designed with slender W24 steel columns were primarily damaged due to column twisting (see Figure 45) and base plate uplift.

Figure 42. Steel industrial building damaged by impact

Figure 43. Bolt fracture at tie rods

Figure 44. Bending of the steel girder at the roof of the steel industrial building due to impact

Figure 45. Lateral torsional buckling of a W24 column due to impact at about mid-height

Our last stop during day 3 included the building shown in Figure 46, which is a management and safeguard building. This building had a pile foundation because of bad soil conditions of the fishing market area. As shown from Figures 47 and 48, liquefaction caused scouring and everything flowed around the building.

Figure 46. Management and safeguard building

Figure 47. Pile foundation #1 after liquefaction

Figure 48. Pile foundation #2 after liquefaction

 

In the same street there was one more building that its pile foundation had similar problems with the ones shown in Figures 47 and 48.

 

 

 

 

Day 4 (June 5, 2011)

During the last day of our trip we mostly visited residential steel or composite buildings and steel parking garages located in the Oroshimachi area that were mostly damaged due to earthquake shaking. The main structures that we visited are summarized as follows:

11-story SRC building: The building shown in Figure 49 is located in the K-Q plaza and was designed on pile foundation in 1975. The steel columns of this building are encased with concrete all the way up to the last story since the building height is above 21m (design regulation in the Sendai area). The 11-story SRC building has a U-shape plan view and consists of 3 buildings (2 in the EW and one in the NS loading direction, respectively) with a 9cm gap. The bed rock is located about 20m from the ground surface. Due to the soil conditions the ground motion amplified about 2 times compared to the bed rock in this area. Several shear cracks were observed in stories 1 to 9 in the exterior walls that were cast in place reinforced concrete (see Figure 50). These walls are designed for temperature control and they are not supposed to be designed for strength.

Figure 49. 11-story SRC apartment building

Figure 50. Shear cracks at exterior walls of the 11-story SRC building

Figure 51. Indication of pounding (11-story SRC building)

There was indication of pounding at the interface of the two buildings in the EW direction with the one in the NS loading direction due to severe cracking at the upper 5-stories of the SRC building as shown in Figure 51.

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Non-structural damage: Most of the steel residential/industrial buildings in the area included ALC panels that were rigidly connected with the structural system (old japanese installation method). Note that ALC panels have a minimum specified compressive strength of 3MPa, a minimum thickness of 100mm and are typically used in 600mm wide modules. Figures 5253 and 54 show typical damage of the ALC panels.

Figure 52. Nonstructural damage due to earthquake (exterior walls)

Figure 53. Typical ALC panel

Figure 54. Complete loss of exterior wall made of ALC panels

Little to no damage to ALC panels was observed in newer residential steel buildings. For these buildings the sliding or rotating panel installation method is employed in which reinforcing barss are disconnected at the individual stories.

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3-story braced frame building: The 3-story building shown in Figure 55 consists of a 1-bay steel MRF in the EW loading direction and two 8-bay steel X-braced frames in the NS loading direction. This building was designed in the 1970s. The steel braces consist of double angles with thin gusset plates at the crossing of the double angle braces. Many net section fractures occurred at the gusset plate connections at the end of these braces (see Figure 56). Panel zone yielding occurred in the EW loading direction due to the cyclic loading (see Figure 57). All the braces at the first story buckled in a lateral torsional mode (see Figure 58) due to the thin gusset plates at the location of cross-bracing.

Figure 55. 3-story office building in the Oroshimachi area

Figure 56. Net section fracture at first story double angle X-brace (3-story office building)

Figure 57. Panel zone yielding of the steel MRF in the EW loading direction (3-story office building)

Figure 58. Lateral torsional buckling of the double angle steel braces due to thin gusset plates (3-story office building)

Parking Garage #1 with Steel Braces:  The 2-story parking garage shown in Figure 59 has eccentrically braced frames in both loading directions as its primary lateral resisting system. The steel braces are HSS sections with gusset plate connections. These braces were designed in a way that they were not allowed to buckle during an earthquake. However, plastic deformation was concentrated in the gusset plates in the short distance between the end of the brace and the overlap with the gusset plate from the columns (see Figure 60).

Figure 59. Parking garage #1 with steel braces

Figure 60. Gusset plate yielding (Parking garage #1)

Figure 61. Gusset plate buckling (Parking Garage #1)

At the interior brace foundations there was foundation uplift  due to the unbalanced load that was delivered to the foundation due to gusset plate local buckling (see Figure 61).

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Parking Garage #2 with Steel Braces: The parking garage shown in Figure 62 was designed in 1991. In the EW loading directions all the top gusset plates fractured due to low cycle fatigue as shown in Figures 63 and 64. Note that none of these gusset plate details included any stiffener to prevent the out-of-plane movement of the gusset. Fracture initiated at the tow of the weld in the heat affected zone and propagated along the length of the gusset plate as shown in Figure 65. Due to gusset plate fracture outside the separation between the concrete slab and the top of the beam indicated unbalanced loading that was successfully delivered to the columns. Note that in the NS loading direction the primary damage was local buckling of the top gusset plates. However, none of them fractured because the ground motion component in this loading direction was not as strong as the one in the EW direction.

 

Figure 62. Parking garage #2 with steel braces

Figure 63. Fracture of both top gusset plates in EW loading direction (Parking Garage #2)

Figure 64. Fracture of top gusset plate (Parking Garage #2)

 

 

 

 

 

 

 

 

Figure 65. Fracture initiation at the tow of the weld (Parking Garage #2)

At the end of the day we returned back to Tokyo with Shinkansen where we all departed to our way back. Many thanks to EERI and members of US and Japan steel reconnaissance team.


Presentation of March 11th 2011 Tohoku earthquake and tsunami observations

July 21, 2011 by

ITIC Tsunami Bulletin Board

The UK-based Earthquake Engineering Field Investigation Team (EEFIT) last week presented their findings in London, from their field investigation of earthquake and tsunami impacts in Iwate, Miyagi and Fukushima prefectures. The team was in the field at the end of May / beginning of June.

The recorded presentation is available at:

http://www.istructe.org/knowledge/webinars/Pages/default.aspx

Observations presented include ground motion observations, geotechnical aspects, structural damage from both ground shaking and  tsunami, performance of coastal defences, impact of the event on the nuclear sector, and aspects of the disaster response and recovery.

The corresponding field report will be published in due course on the reports page of the same website, where previous field reports can also be viewed: http://www.istructe.org/knowledge/EEFIT/Pages/reports.aspx


TCLEE presentation of findings now available

July 1, 2011 by

The ASCE – Technical Council on Lifeline Earthquake Engineering (TCLEE) recently returned from a field trip (June 2011) to investigate lifeline performance in the Tohoku Japan March 2011 earthquake. The team was led by Curt Edwards, supported by Alex Tang, Leon Kempner, Yumei Wang, Alison Pyrch, Mark Yashinsky, John Eidinger and Alexis Kwasinski.

Damage was extensive… coal, oil and gas-power plants, wastewater treatment plants, substations, water transmission and distribution pipelines, highways, penstocks, telecom, all had various forms of tsunami and shaking damage. Some mitigation measures worked well; others not so much. Rapid response was much improved as compared to Kobe 1995.

A 60-page presentation is available for download (free), covering: power, water, wastewater, highways, railways, telecommunications, liquid fuels, fire following earthquake / tsunami, as well as geology and geotechnical issues that affect all; as well as examples of tsunami vertical evacuation structures. It can be downloaded from:

www.geEngineeringSystems.com.  ASCE TCLEE short reports covering this and other recent earthquakes are available for download from www.asce.org/Content.aspx?id=2147488653.


EERI/ISSS Team: Government and Community Response

June 28, 2011 by

Our US EERI Social Science and Government Inspection Team is multidisciplinary with collaboration between researchers and practitioners. It is interesting to note the majority of this EERI team are women compared to other professional reconnaissance teams in the field.

US EERI Social Science Team in Rikuzen Takada, June 21, 2011. Photo H. Chen

  • Prof. Stephanie Chang, University of British Columbia, UBC Centre for Human Settlements (Team Lead)
  • Prof. Daniel Aldrich, Purdue University
  • Ms. Rochelle Brittingham, Graduate Research Assistant, University of Delaware, Disaster Research Center
  • Mr. Richard Eisner, EERI Member and California Office of Emergency Services (Retired)
  • Dr. Kanako Iuchi, The World Bank, Finance, Economics and Urban Department
  • Dr. Laurie Johnson, Laurie Johnson Consulting and Research
  • Prof. Terri Norton, University of Nebraska, Durham School of Architecture Engineering and Construction
  • Ms. Sahar Safaie, The World Bank, Global Facility for Disaster Reduction and Recovery
  • Prof. Kathleen Tierney, University of Colorado, Natural Hazards Research and Applications Center
  • Prof. Tricia Wachtendorf, University of Delaware, Disaster Research Center
  • Mr. Jay Wilson, Hazard Mitigation Coordinator, Dept. of Emergency Management, Clackamas County, Oregon

Our US EERI team was joined by counterparts from Taiwan and Korea as an international social science and government inspection team hosted through the Institute for Social Safety Science (ISSS). The field reconnaissance planning, situational context, translation and logistics were provided by a diverse group of professors and graduate students from a number of Japanese social science and disaster research institutions. We especially wish to thank the following people for their generous time, gracious hospitality and professional collaboration:

  • Prof. Shigeo Tatsuki, Doshisa University, Kyoto (Team Management)
  • Prof. Norio Maki, Kyoto University (Team Management)
  • Prof. Haruo Hayashi, Kyoto University
  • Emeritus Prof. Kunihiko Hirai, Nagaoka Institute of Design
  • Mr. Yoshinobu Fukasawa, Fire and Disaster Management Agency
  • Prof. Eiko Ishikawa, Disaster Reduction and Human Innovation Institute
  • Prof. Ikuo Kobayashi, Kobe Yamate University
  • Prof. Shunichi Koshimura, Tohoku University
  • Prof. Osamu Murao,  University of Tsukuba
  • Prof. Kazuyoshi Ohnishi, Kobe University
  • Mr. Kazuo Sato, Iwate Prefecture
  • Prof. Kishie Shigekawa, Fuji Tohoka University
  • Prof. Satoshi Tanaka, Fuji Tohoka University
  • Prof. Yasushi Takeuchi, Miyagi University

Translators and Logistic:

  • Prof. Haili Chen, Research Assistant Professor, Kyoto University
  • Ms. Nicolle Comafay, PhD Candidate, Doshisha University
  • And most importantly, logistics by Ms. Yoshimi Amakawa, Co-operative PLANners Associates

Our team also appreciates the above and beyond efforts from all of the local governments and related institutions/organizations for their time in preparing documents, providing lectures and participating in question and answer sessions, despite all of the demands from their busy schedules.

 

Starting Off –We departed from Tokyo on Sunday, June 19th and traveled to Morioka, in north central Tohoku.  There we received an evening briefing from Iwate Prefecture government officials on the emergency response and reconstruction proposals. We were told many of the coastal communities have little or no capacity to deal with the overwhelming nature of this disaster and must rely on the assistance from the Prefecture government. Key issues that we are examining are sheltering, temporary housing, support for vulnerable populations,  emergency warning and response, economic impacts, debris management and the process of recovery.

Our field reconnaissance began on Monday, June 20th as we traveled along the Sanriku Coastline starting in Northern Iwate Prefecture.  Over several days traveled south into Miyagi Prefecture and finished in Natori City on Friday, June 24th . We had scheduled observations or visits in a dozen communities, some large and metropolitan, but many were small and dependent on their fishing ports.

The timing of this reconnaissance was at the 100 day post-event timeline and provided a unique opportunity to see the transition from response into the early stages of recovery planning. Many communities will be working for years on repairs and cleanup operations, but visioning for the reconstruction is already taking place. One of the best aspects of the visit was our ability to interact at the local, prefecture and national government levels and better understand the nature of Japanese disaster management.

The Japanese employ three types of countermeasures for tsunami: 1) defense structures such as coastal dikes, sea walls, and break-waters; 2) tsunami-resistant town structures such as forest buffers, relocating structures to higher elevations or inland, evacuation routes; and 3) soft-wares such as warning and evacuation. We observed and discussed the performance of all of these types of protective activities with public officials and our Japanese colleagues. We were able to note the different approaches to response and recovery between prefectures and saw a large range of capacities between communities at the local level.

Probably the most significant aspect of this event is the fact that a M 9.0 earthquake was not considered possible by a consensus of the scientific community. By not understanding the extreme possibility that this size of event could occur, every other component of disaster management at the local, regional and national level was overwhelmed by the scale of the tsunami. This was the epitome of a low probability and high consequence event.

On an positive note, for the magnitude of this great earthquake, we saw minimal seismic damage on our travels along the coast. Compared to what we might expect to see for a similar event in the Pacific Northwest, Japan faired well from the earthquake itself.

Iwate Prefecture
Day One: Kuji, Noda, Taro, Miyako, Yamada and Ootsuchi
Taro is notable for its massive 10-meter high sea wall built following the 1933 tsunami. It was referred to as the “Great Wall” like in China as it stood between the harbor and most of the city. There was concern that more recent developments that had been permitted outside the main sea wall area would be vulnerable to a larger probable tsunami, and they even installed a lesser sea wall for that area too – but all were overwhelmed from the severity of this great tsunami. We attended a presentation in the city hall with a vivid retelling of one man’s retreat to the third floor and his capturing the overtopping of the main wall with photographs.

EERI Team examining Taro from atop their 10 meter sea wall. Photo J. Wilson

In Miyako we received a briefing from a Prefecture official and I investigated the remains of a fire station which housed the area’s warning sirens. In hindsight I wondered what capacity exists now to respond to fires for the remaining non-damaged homes on higher ground.  Our last stop that day was in Ootsuchi where we received a briefing from a Prefectural representative on their recovery proposal and then a separate briefing on debris management. We saw a shelter from the outside with a traveling van that provided eye examinations and fitted glasses for tsunami refugees.

Fire Station In Miyako with warning sirens on tower. Photo J. Wilson

 

Briefing from Iwate Prefecture official in Ootsuchi. Photo J. Wilson

Day Two: Kamaishi, Oofunato, Rikuzen Takada and Iwate workshop
Our second day provided our team with views of increasing scales of destruction as we headed south. All along the way we saw clusters of homes, businesses and infrastructure in the rural areas, but it seemed like each city presented more widespread damage.

In Kamaishi we visited with a representative from the port authority on their impacts and business resumption. Our hosts pointed out the damage to the vast tsunami breakwater near the mouth of their harbor. We also stopped by a fish hatchery where we saw evidence of damage to their facilities. Following the earthquake, their two research vessels took immediate action and managed to escape Kamaishi harbor before the tsunami’s arrival. In Oofunato we were given a presentation at their fire station headquarters on preparedness measures. We heard their 12noon testing of the tsunami alert system, which also plays at 7am and 5pm every day.

Construction of temporary housing near Kamaishi. Photo J. Wilson

Rikuzen Takada was impressive for the wide area affected and the mountains of debris being sorted. We attended a briefing outdoors near the shore by a wedge shaped building with bleacher-type seats facing the ocean. We were told it was the office of their Chamber of Commerce and was a designated tsunami evacuation building. According to a recent tsunami survey report from Dr. Shingo Suzuki and others, the inundation level at this building was 12.8 meters. Near by was the City’s debris sorting area with mountains of various materials. There was strong evidence of subsidence along their harbor and inland behind the main highway.

Debris sorting at Rikuzen Takada. Photo J.Wilson

The evening of Day two our team and the Korean and Taiwanese members participated in a workshop hosted by Iwate Prefecture officials asking for listing our findings and recommendations. While we all provided examples, the EERI team will need time to digest all we have seen and provide our thoughts in our upcoming EERI newsletter.

Miyagi Prefecture
Day Three: Ishinomaki
My first impression of Ishinomaki was of all  the dead ornamental pine trees in yards and roadsides as we drove through the city. At first i wonderd if salt water had infiltrated the ground water, but I later learned  it was from the broad inundation across much of the area. When we arrived at their City Hall, we saw widespread evidence of liquefaction along the sidewalks and there was the pervasive musty smell of flood damage. Inside we learned that City Hall was inundated up to 1.5 meters and the area had standing water for 4-5 days. Employees had to use a makeshift platform to gain access to the building and it took one month to reopen for business. As of June 13th, Ishinomaki had the highest number of people killed (3,025) or still missing (2,770) from the tsunami. They told us 6,000 people were still in shelters. When Dr. Terri Norton inquired about their debris management plan, we were told they estimate it may take 100 years to process based on their annual capacity. Debris had been collected into 19 sites and most was already separated. We surveyed a heavily damaged bayside industrial facility, their fish market area, and then toured a shelter at Minami Elementary School. We finished our day at Ishinomaki Senshu University and learned how the campus hosts the area’s volunteer center with volunteers camping in tents and cars along the roadside.

Nicolle Comafay translates disaster assistance process at Ishinomaki City Hall. Photo J. Wilson

 

Uplifting poster in Ishinomaki shelter. Photo J. Wilson

Day Four: Minami Sanriku and Kesennuma
For me, Minami Sanriku was the city where I felt the most personal connection to this disaster and the sense of loss was so strong. Maybe it was having seen several online videos of the tsunami tearing through the City, but it was also learning about heroic efforts from the City’s emergency management staff as their operation center was being overwhelmed and the tragic situation at their City hospital, which was flooded up the 4th floor.

Minami Sanriku Emergency Operation Center. Photo J. Wilson

After a tour around the harbor by members of the fishing fleet, we were treated to a homemade Hotate (scallop) soup, the last batch from their annual harvest. I was struck by the warm reception we received from this group who were so impacted themselves. At our departure the fishermen all lined up to wave goodbye. As we drove off, the dismal surroundings of the empty city made me think what strong hearts these people must have to endure so much and remain there to carry on.  It was almost too much for me just being there for a few hours. At a  presentation later that day from a Prefecture-level recovery team, we learned Minami Sanriku estimates 700,000 tons of debris to be cleared, sorted and reused, recycled or disposed of.

Hotate soup with bento box lunch in Minami Sanriku. Photo J. Wilson

 

Minami Sanriku fishermen waving goodbye. Photo J. Wilson

In Kesennuma, we met with the manager of the City’s business district. He gave us an evening tour of the devastated fishing market and we saw evidence of subsidence  with many blocks having standing water during the high tide. Before saying goodbye, he led our bus on a tour around the dark and empty business district as he described a range of plans for the area’s recovery. He expressed optimism that because his business and home were both destroyed, he now had more time to dedicate to his hobby of painting and shared a beautiful post card he made of Kesennuma harbor.

Day Five: Sendai and Natori City
Our last day in the field was in Sendai, the Prefectural center. In the morning we met with Welfare Association for the Disabled and the Japan  Disability Forum. The representatives painted a desperate picture of tens of thousands of disabled residents along the Miyagi coast, but only 2,000 have been located and receiving assistance. The institutions and support networks are broken and due to privacy laws, they are unable to access records to  better locate and  track displaced people with disabilities.

During our lunch stop several team members surveyed an earthquake damaged condominium that had one tower leaning out of plumb. We were told there would be efforts to repair the work, but it would likely take years for completion.

At prefecture headquarters we met with Mr. Takehiro Mori from the National Disaster Management office. He explained they are working from the Local Disaster Response Headquarters, which is similar to a FEMA Joint Field Office. Typically their office works from Tokyo, but he expected this co-located office in the Prefecture would become more of the standard. Because the scale of this disaster is so vast over multiple prefectures, they could only operate from one prefecture headquarters and he admitted that other affected prefectures like Iwate to the north was not receiving the same level of support due to limited resources.

National Emergency Operations Center co-located in Miyagi Prefecture Headquaters. Photo J. Wilson

We concluded our last day in Natori City and got a briefing on their damages and initial steps to develop and adopt a recovery plan. It was impressive to see the level of detail and the emphasis on visioning a new future. We toured an area called Yuriage, that many people around the world saw on television as the helicopter camera tracked the initial tsunami surge engulfing green-houses, slamming into elevated roadways carrying vehicles and quickly penetrating up into adjacent canals. Dr. Shunichi Koshimura was very gracious to accompany us on our tour and answer many complex questions about tsunami hazard modeling and evacuation planning.

Flowers in memory of tsunami victims at a shrine on Hiyori Yama in Yuriage. Photo J. Wilson

On Saturday, June 25th, we returned to Tokyo for a concluding workshop to develop research proposal ideas and international research partnerships. We learned this event is responsible for the loss of 270,000 housing units. Because sea walls and breakwaters are vital for harbor protection, many communities remain vulnerable now as typhoon season ramps up. It will be a challenge to find ways to take urgent protective measures that tie into and build on the emerging long-term recovery plans.

Speaking for myself, I return to Oregon with a new-found sense of purpose to bring these observations and lessons home and to try to elevate risk reduction measures and pre-disaster recovery planning in the Pacific Northwest. Many of the lessons on vulnerable populations, response capacity, and the transitioning of sheltering into temporary housing and then community reconstruction can apply to any number of disaster situations as well.

Stay tuned for the upcoming EERI newsletter and future publications from our team members.


FHWA/UJNR/EERI Reconnaissance Team for Bridge Damage Investigation

June 8, 2011 by

US Team
W. Philip Yen, US side Chair of T/C G, Federal Highway Administration
Ian Buckle, Professor, University of Nevada, Reno
David Frost, Professor, Georgia Institute of Technology, Atlanta
Lee Marsh, Senior Project Manager, Berger/ABAM Engineers, Seattle
Shideh Dashti, Assistant Professor, University of Colorado, Boulder
Eric Monzon, Research Assistant, University of Nevada, Reno

Japan Team
Tetsuro Kuwabara, Japan side Chair of T/C G, Director of Bridge Structure Research Group, CAESAR, PWRI
Keiichi Tamura, Japan side Secretary General of UJNR Panel on Wind and Seismic Effect, Research Coordinator for Earthquake Engineering, PWRI
Jun-ichi Hoshikuma, Chief Researcher, CAESAR, PWRI
Taku Hanai, Senior Researcher, CAESAR, PWRI
Hideaki Nishida, Senior Researcher, CAESAR, PWRI
Shigeki Unjoh, Research Coordinator for Earthquake Disaster Prevention, Research Center for Disaster Risk Management, NILIM, MLITT
Kazuhiko Kawashima, Professor, Tokyo Institute of Technology

Disclaimer: All comments/opinions/observations are preliminary and my own (Eric Monzon) and do not necessarily represent the views of all the reconnaisance members.

Day 1 (June 3, 2011)

After a brief breakfast meeting with the US Team, we checked out of Hilton Narita and met up with the Japanese Team. We headed to Tokyo via the Narita Express and then to Sendai on Shinkansen. Arrived Sendai at noon then checked in at the Koyo Grand Hotel.

Our first stop was at the office of Tohoku Regional Bureau of the Ministry of Land, Infrastructure, Transport and Tourism (MLITT) where the director gave a brief presentation on the critical role of the MLITT on rescue, structure inspection, rehabilitation, and supporting local governments and victims.

Next stop was the Sendai-Tohbu viaduct, our first bridge. Nexco engineers working on the bridge repair were kind enough to give us an overview of the structure damage and provided plans of the bridge. Damage to the elastomeric bearings were mainly concentrated at Piers 52 and 56 where the superstructure changes from steel I-girders to steel box girders. The substructure also changes from single-column piers to two-column piers. The damage to Pier 56 includes buckling of girder web and cross-frame.

Day 2 (June 4, 2011)

We left the hotel at 8:30AM and headed to the coastal areas to see the bridges that were damaged by tsunami. At 11:10AM, we arrived at Koizumi O-hashi – a 6-span steel I-girder bridge. The piers are still standing (except the one that collapsed possibly due to scouring) but the superstructure was washed away about ¼ mile upstream of the river. Several spans of the railway bridge that runs perpendicular to the bridge were also washed away by the tsunami. Houses were lifted onto the deck of the railway bridge.

Next stop was the Sodeo-gawa hashi – a 4-span curved bridge. The main deck survived the tsunami but the deck of the adjacent pedestrian bridge was washed away. Since the deck of the pedestrian bridge was not tied to the substructure, the deck was lifted by the tsunami waves and was swept away about 300 ft upstream of the river.

Next bridge was the Nijyu-ichihama hashi. This is a single span bridge with pedestrian bridges added on both sides of the main deck. The bridge is still standing but all the abutment backfill were washed away. The same is true for the nearby railway bridge.

Volunteers are on the area helping on the cleanup.

About 12 minutes drive south of Nijyu-ichihama is Utatsu O-hashi. Several spans of the bridge deck were swept away but the columns are still standing. Inclined cracks were observed on the concrete I-girders of the spans that are still standing. This could be due to the torsion in the girders as the tsunami waves pushed the superstructure.

Last stop was the Shida hashi – a multispan steel girder bridge built in 1957. The approach slab settled by about 6 in. and cracks were found on the abutment backwall. At Piers 1 and 6 (two-column bents), there are cracks at the bottom and at the top (about 3 ft measured from haunch) of the columns. Pier 6 is close to the river and liquefaction most likely happened while Pier 1 is next to the abutment where the approach slab settled. In addition, the anchor bolts of the steel bearings on Piers 1 and 6 have yielded.

Day 3 (June 5, 2011)

Prof. Kawashima joined the recon team then we headed to Sendai O-hashi. On the bus, Hoshikuma-san briefed us about the bridge – built in 1965, was damaged by the 1978 Miyagi Earthquake, was retrofitted with fiber wrap, and the bridge performed well during the earthquake. There are sink holes (about 2 ft by 3 ft) near the base of the pier that is close to the river.

Next stop was the Yuriage O-hashi that spans the Natorigawa River. The main span is reinforced concrete box while the end spans are concrete I-girders. The bearings at the joint between the exterior spans and main spans were severely damaged. The longitudinal movement is about 15 in.

Dr. Frost was leaving to US on that day. We dropped him off at the Shinkansen station in Sendai before heading to Ezaki O-hashi which is about 2.5 hours drive north. This is 9-span steel girder bridge that was designed based on the pre-1980 code but was constructed in 1982. The shorter piers, Piers 5, 6, 7, and 8, were damaged by main shock but have been repaired.

Last stop was at Fuji hashi, about 25 minutes drive south of Ezaki O-hashi. The bridge was not damaged by the main shock but was damaged by the aftershocks because the epicenters are closer to the bridge. Pier 6 is being retrofitted with reinforced concrete jacket while Pier 7 has been retrofitted with fiber wrap to increase their shear capacity.

Day 4 (June 6, 2011)

At 8:30AM we checked out of Koyo Grand Hotel then took the Shinkansen to Tokyo. Dr. Buckle and Dr. Yen transferred to Narita Express because they were leaving to US that day. After lunch at a Mexican restaurant, we headed to Arakawa Wangan bridge. This is a long span steel truss bridge where the joint connections were damaged during the earthquake. Actually, before the earthquake, the bridge was being retrofitted by adding dampers, increasing the member strength, and replacing the bearings. Some of the gusset plates buckled and some were fractured. The bridge was closed for about 11 days while the damaged gusset plates were being repaired or replaced. We were told by the Metropolitan Expressway engineers that the average daily traffic on the bridge is about 80,000 vehicles.

Last stop of the recon team was at Urayasu-shi of Chiba Prefecture, a residential area, where extensive liquefaction occurred. In the area that we visited, the ground settlement is up to 20 in.

Day 5 (June 7, 2011)

Back to Reno via San Francisco. Many thanks to FHWA, EERI, and members of US and Japan Team.


Shideh Dashti’s Geotechnical Observations from Trip to Sendai, Japan

June 7, 2011 by

June 3, 2011:

After meeting our Japanese colleagues on Friday, June 3rd at the hotel, we took the train from Narita Hilton Hotel to Tokyo and then Sendai. In Sendai, we first visited the Tohoku Regional Development Bureau (MLIT). They described the existing emergency response protocols for earthquake and tsunami. We then headed to the Sendai-Tohbu Viaduct (East Nippon Expressway Co. Ltd), a bridge with failed elastomeric bearings during the March 11th earthquake. There was very little evidence of liquefaction near the bridge, but the softening of the foundation soil in general seemed to be a minor and local effect that did not influence the performance of the bridge.

June 4, 2011:

We headed for the coastal areas that were damaged the most due to the tsunami (about 2-hour ride with the bus from Sendai). The scale of the damage was significant, miles and miles of complete destruction. We saw groups of volunteers from around the country working to help clean up the debris.

We first visited the Mizushiri hashi bridge. The piers seemed to have performed well, but the deck washed away. A smaller adjacent bridge had evidence of scouring and rotated columns. Although it was difficult to verify closely, their foundation seemed to be in place with no damage. But the columns and their connecting steel reinforcement to the lower pile cap seemed to have failed due to flow.

Later in the day, we visited a bridge that was slightly affected by soil liquefaction near the abutments. More importantly, we observed the failure of a section of a levee adjacent to the bridge. This failure was due to liquefaction and countermeasures were already in place before the rainy season in Japan begins (around June). They had completed a temporary river dike with sheet pile walls, which will be removed after the dike is permanently repaired.

June 5, 2011:

We visited a few bridges that had been retrofitted following the 1978 earthquake in Japan. Some performed well under the experienced ground motions, some didn’t. There was one bridge that suffered damage only during a strong aftershock.

There was considerable evidence of liquefaction near these bridges. Sink holes were observed near the piers. In some cases, the entire area was covered with sand ejecta. However, the bridge columns were founded on piles and did not seem to have been affected by soil softening and the settlement of the surrounding soil.

June 6, 2011:

We took the train back to Tokyo from Sendai in the morning. After visiting one bridge, we visited a site located south-east of Tokyo with buildings that were affected by liquefaction (Urayasu-Shi). Soil softening had caused significant damage to pipelines and manholes as well as sidewalks.  In many cases, the ground had settled in a non-uniform manner around the buildings (up to 14-15 inches), but structures that were on pile foundations had not moved and were intact. One structure that appeared to have shallow foundations had settled more than the surrounding soil, as expected. There was evidence of lateral spreading near a bridge as well, causing very minor damage (movement in the order of 1 to 2 inches).  Liquefaction is “Ekijyoka” in Japanese.


Blog Entries by Professor Lori Dengler on tsunami damage

May 24, 2011 by

Click here to view

Blog written by Lori Dengler, Humboldt State University.


Japan Reconnaissance Photos by Lori Dengler

May 10, 2011 by

Credits: Lori Dengler

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https://picasaweb.google.com/105862892016189181305/TohokuOkiEarthquakeAndTsunami?authkey=Gv1sRgCLvZ4fr9otPZJw&feat=email#

Tohoku Pacific Ocean Earthquake and Tsunami: Quick observations from the PEER/EERI/GEER/Tsunami Field Investigation Team.

April 26, 2011 by

The PEER/EERI/GEER/Tsunami Field Investigation Team has returned from Japan and complied a short interim report of their observations related to the Tohoku Pacific Ocean Earthquake and Tsunami. It is hoped that the contents of this very short interim report may be especially useful to researchers developing and submitting NSF RAPID Proposals.

http://peer.berkeley.edu/news/wp-content/uploads/2011/04/Tohoku-short-interim-report.pdf

The 2011 Tohoku Pacific Ocean Earthquake and Tsunami provides unique and important opportunities advance fundamental knowledge and mitigate future earthquake disasters due to the:

  • Scope and scale of the damage to engineered facilities and lifeline systems in general, and widespread consequences of this damage,
  • Likely long term effects on society of very low probability, but high consequence phenomena such as the tsunami and damage to the Fukushima Daiichi Nuclear Power Plants,
  • Substantial amount of instrumentation installed throughout Japan to measure the movement of the ground, water and structures,
  • Highly detailed documentation being compiled of the direct damage and of the economic, social, political, medical and other impacts, and
  • Longstanding and strong collaborative ties between US and Japanese scientists and engineers.

Based on the discussions with Japanese engineers and officials, and quick inspections of damages in the Tohoku and Kanto regions, the PEER/EERI/GEER/Tsunami field investigation team, has identified the following key areas related to engineering as being of high priority that would benefit from further intensive immediate study by US, Japanese and other investigators.

1.     The tsunami and its effects
2.     Liquefaction or settlement-related damage to structures
3.     The nuclear power plant and related issues
4.     Disruption of Business and Social Systems
5.     The effect of the earthquake shaking on engineered facilities

For more details, read the complete short interim report that can be downloaded from the link above.  A more detailed report will be released soon, and a web-cast seminar is being planned.