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Tacloban - Philippines Typhoon Haiyan (Yolanda) 8 November 2013 Damage Assessment Report Shalini Jagnarine-Azan MSc, CEng, MIStructE, D.I.C. Date: 20 February, 2014
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Contents Introduction ....................................................................................................................................................... 3
The Philippines ................................................................................................................................................... 4
Socio-‐Economic Situation of the Philippines ...................................................................................................... 5
History of Natural Hazards ................................................................................................................................. 5
Philippines Building Codes ................................................................................................................................. 7
Typhoon Yolanda (Haiyan) ................................................................................................................................. 8
Tacloban City .................................................................................................................................................... 13
Impact of Typhoon Yolanda on Tacloban City .................................................................................................. 14
Wind Impact ................................................................................................................................................. 15
Storm Surge .................................................................................................................................................. 16
Rainfall .......................................................................................................................................................... 19
Hospitals in Tacloban ....................................................................................................................................... 20
Eastern Visayas Regional Medical Centre .................................................................................................... 21
Activities ................................................................................................................................................... 23
Mother of Mercy Hospital (Private) ............................................................................................................. 24
Activities ................................................................................................................................................... 26
Bethany Hospital .......................................................................................................................................... 26
Activities ................................................................................................................................................... 27
Damage Assessment ........................................................................................................................................ 28
Wind ............................................................................................................................................................. 28
Combination Storm Surge and Wind ............................................................................................................ 35
Debris Impact ............................................................................................................................................... 37
Non-‐Structural Damage ................................................................................................................................ 39
Impact on People ......................................................................................................................................... 42
Conclusions ...................................................................................................................................................... 44
Recommendations ........................................................................................................................................... 45
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Introduction Following the impact of Typhoon Haiyan (locally referred to as Yolanda) in the Philippines, I was deployed as a Structural Engineer to provide technical assistance in the emergency response on behalf of the World Health Organization, in secondment from the Pan American Health Organization. I arrived in the Philippines on November 13, 2013 and spent approximately 6 weeks in Tacloban City, which was the most severely affected city in the Philippines. This paper presents my findings and observations of the impact of Typhoon Yolanda on the Philippines and more specifically on Tacloban. The paper comprises two parts. Part one reviews the vulnerabilities of the country, in order to develop an understanding of what made it so susceptible to disaster with the impact of Yolanda. It also presents the three natural factors of super typhoon Yolanda, wind speeds, storm surge and rainfall that caused the most detrimental consequences on the lives, infrastructure and economy of Tacloban. Part 2 gives a pictoral overview of the structural and non-‐structural damage observed in Tacloban, as well as some of the observed immediate impact on the people of Tacloban. The damage are categorised into predominantly damage due to hydrodynamic forces from wind, hydrostatic forces from storm surge and rainfall, and a combination of the preceding two through debris damage.
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The Philippines The Philippines1 is an archipelago chain of 7,107 islands with more than 36,000 kilometres of coastline. It has a total land mass of approximately 300,000 square kilometres (115,831 square miles), located about 800km from the Asian mainland, between Taiwan and Borneo in East Asia and the Pacific. The 11 largest islands contain about 94% of the total population, whilst only 1000 of the islands are populated. Luzon is the largest, which is where the national capital region (NCR), Metropolitan or Metro Manila is located. Mindanao is the second largest island. The islands are divided into three groups: Luzon, Visayas and Mindanao. Visayas is the group of islands in the central Philippines containing Panay, Negros, Cebu, Bohol, Leyte and Samar. The path of the Typhoon traversed Visayas and made landfall seven times and the most severely affected area was Eastern Visayas also known as Region VIII.
Figure 2 -‐ Map of the World
1 http://en.wikipedia.org/wiki/Geography_of_the_Philippines
The Philippines
Figure 1 -‐ Map of the Philippines
Eastern Visayas
Figure 3 -‐ Eastern Visayas consists of Leyte, Samar and Biliran Islands
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Socio-‐Economic Situation of the Philippines The Philippines is defined as a 2lower middle income developing nation in East Asia and Pacific. In 2012 the estimated total population was 96.71 million with an annual Gross Domestic Product of US $250.2 billion. Approximately 26% of the overall population was found to be below the poverty line, according to the last estimates done in 2009. The Multidimensional Poverty Index (MPI) for Philippines in 2006 was recorded as 0.064 (the lower the index the lower the poverty level). In terms of corruption, the 3Corruption Perceptions Index for 2013 was calculated at 36, which gave it a rank of 94th most corrupt out of 177 countries in the world.
History of Natural Hazards The Philippines is one of the most hazard-‐prone countries in the World. It is normally impacted by at least 20 typhoons annually and is also prone to earthquakes and volcanic activity. The Philippines straddles the Typhoon belt and is susceptible to the impact of tropical storms and typhoons typically between July to October. Storms and Typhoons are especially hazardous for northern and eastern Luzon, and the Bicol and Eastern Visayas region. The country’s origins are also volcanic in nature and it is situated on the Pacific Ring of Fire, which is an area in the Pacific Ocean basin where a large number of earthquakes and volcanic eruptions occur. In a study conducted by the World Bank in 2008, approximately 50.3% of the total land mass area and 81.3% of its population are vulnerable to the impact of natural hazards. Table 1 -‐ Summary of recent major events disasters in the Philippines
Event Damage Estimate Effect on GDP
Affected Deaths
9 Nov 2013 – Super Typhoon Yolanda P35 billion (US $788 mil.) 14.1 million 6,200
15 Oct 2013 – 7.2M Bohol Earthquake P2.5 billion (US $58 mil.) 0.5% 3.2 million 218
*2009 – Storms Ondoy and Pepeng P38 billion (US $853 mil.) 2.7% 9.41 million 929
*42009 was the most disastrous year based on natural disaster statistics between 2000-‐2012, by OFDA/CRED
2 The World Bank Data for 2012 3 The Corruption Index ranks countries on a score of 0 (highly corrupt) to 100 (very clean) from Transparency International, 2013. 4 http://www.senate.gov.ph/publications/AAG%202013-‐04%20-‐%20Natural%20Disasters_final.pdf
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Figure 4
From a recent article by the 5National Geographic, five reasons were listed why the Philippines are especially at risk from natural hazards:
1. Warm ocean waters – temperatures over 28 degrees Celsius are need for typhoons to form and the waters surrounding Indonesia and the Philippines are usually above 28 degrees.
2. Coastal homes – around 60% of the population live along the low-‐lying coastal zone of the Philippines.
3. Deforestation – uncontrolled deforestation in watershed areas. Past typhoons and earthquakes have resulted in mudslides and landslides, which have been exacerbated by the lack of tree roots to stabilize hillsides.
5 http://news.nationalgeographic.com/news/2013/11/131111-‐philippines-‐dangers-‐haiyan-‐yolanda-‐death-‐toll-‐rises/
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4. Ring of Fire – The Philippine archipelago rests on the Pacific Ocean’s Ring of Fire which is where the Pacific Ocean’s crust is being driven under the Continents, resulting in the regularity of earthquakes, volcanic activity and tsunamis.
5. Poverty and Underdevelopment – the young, poor population has increasingly shifted to the vulnerable coastal zones, rapidly constructing inadequate homes with poor urban planning susceptible to strong winds, torrential rains, storm surges and tsunamis; among other hazards.
Philippines 6Building Codes The Ministry of Public Works in the Philippines adopted ‘Implementing Rules and Regulations’ for the newly formed National Building Code in 1978. The regulations stated that to obtain a “certificate of occupancy for buildings constructed after the promulgation of the national building code” under clause 2.1.2.4, ‘Structural and Civil Engineering’ that structural design must comply with the National Structural Code for Buildings.
The 7National Structural Building Code of the Philippines, which was last updated in 2001, referred to as NSCP2001. It had been approved and endorsed by the Professional Regulation Commission in November 2002 and approved as a referral code to the National Building Code in June 2003. It was noted that the NSCP2001 is widely adopted and in use by the structural engineering community.
The NSCP2001 defines the Philippine chain into high, mid-‐ and low wind speed zones. Zone I, the high wind zone, encompasses mainly the eastern Luzon and Visayas and has a 3-‐sec gust wind speed of 250 km/h with a probability of exceedance of 0.02 (or 50-‐year return period).
Using wind conversion factors for Durst (1960), a 3-‐sec gust of 250km/h is equivalent to category 3 hurricane peak wind speeds identified in Table 2 using the Saffir-‐Simpson Scale.
6 Ref: Building Code of the Philippines 7 W.T. Tanzo and B.M. Pacheco, “New Wind Load Provisions in Philippine Structural Code”, website http://ebookily.org/pdf/national-‐structural-‐building-‐code-‐of-‐the-‐philippines, accessed 27 March 2014
Figure 5
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Typhoon Yolanda (Haiyan) Super Typhoon Haiyan, locally called Yolanda, was a category five typhoon, based on the Saffir-‐Simpson Hurricane Wind Scale8. It made landfall in the Philippines islands on November 8, 2013 with maximum recorded one-‐minute sustained wind speeds of 315km/h (196mph) near the eye, recorded by the Joint Typhoon Warning Centre (JTWC) and based on satellite measurements. The JTWC utilises the Dvorak technique to estimate the intensities of tropical storms, cyclones, typhoons, etc. based on visible and infrared satellite images.
8 http://en.wikipedia.org/wiki/Saffir-‐Simpson_hurricane_wind_scale, Debi Iacovelli (July 2001). "The Saffir/Simpson Hurricane Scale: An Interview with Dr. Robert Simpson". Sun-‐Sentinel
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The initial scale was developed by Herbert Saffir, a structural engineer, who in 1969 went on commission for the United Nations to study low-‐cost housing in hurricane-‐prone areas.[4] While performing the study, Saffir realized there was no simple scale for describing the likely effects of a hurricane. Mirroring the utility of the Richter magnitude scale in describing earthquakes, he devised a 1–5 scale based on wind speed that showed expected damage to structures. Herbert Saffir gave the scale to the US National Hurricane Center, NHC, and Robert (Bob) Simpson added the effects of storm surge and flooding. In 2009, the US National Hurricane Center, NHC made moves to eliminate pressure and storm surge ranges from the categories, transforming it into a pure wind scale, called the Saffir-‐Simpson Hurricane Wind Scale (SSHWS).[5] The new scale became operational on May 15, 2010 According to Robert Simpson, there are no reasons for a Category 6 on the Saffir-‐Simpson Scale because it is designed to measure the potential damage of a hurricane to manmade structures. Stating that "...when you get up into winds in excess of 155 mph (249 km/h) you have enough damage if that extreme wind sustains itself for as much as six seconds on a building it's going to cause rupturing damages that are serious no matter how well it's engineered". Table 2 -‐ Saffir-‐Simpson Hurricane Wind Scale (SSHWS)
CATEGORY SUSTAINED WIND SPEEDS
(peak 1-‐min at 10m unobstructed exposure)
DAMAGE
Tropical Storm
63-‐118 km/h, 39-‐73 mph, 18-‐32 m/s
One 119-‐153 km/h, 74-‐95 mph, 33-‐42 m/s
Very dangerous winds will produce some damage Minor damage to exterior of homes Toppled tree branches, uprooting of smaller trees Extensive damage to power lines, power outages
Two 154-‐177 km/h, 96-‐110 mph, 43-‐49 m/s
Extremely dangerous winds will cause extensive damage Major damage to exterior of homes Uprooting of small trees and many roads blocked Guaranteed power outages for long periods of time – days to weeks
Three 178-‐208 km/h, 111-‐129 mph, 50-‐58 m/s
Devastating damage will occur Extensive damage to exterior of homes Many trees uprooted and many roads blocked Extremely limited availability of water and electricity
Four 209-‐251 km/h, 130-‐156 mph, 59-‐70 m/s
Catastrophic damage will occur Loss of roof structure and/or some exterior walls Most trees uprooted and most power lines down Isolated residential due to debris pile up Power outages lasting for weeks to months
Five ≥ 252 km/h, ≥ 157 mph, ≥ 70 m/s
Catastrophic damage will occur A high percentage of homes will be destroyed Fallen trees and power lines isolate residential areas Power outages lasting for weeks to months Most areas will be uninhabitable
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It is important to note that the use of the 9Richter scale to identify magnitudes of earthquakes has been superseded by the development of various types of measuring scales. The common types include the duration magnitude, surface-‐wave magnitude and moment magnitude. This is because the Richter scale magnitude, ML was only found to be applicable to moderate-‐size seismic events, that is, 3 < ML < 7. Most earthquakes are now commonly stated as ‘Magnitude’ without specifying the measurement scale used. 10Additionally, differing to the statement made by Bob Simpson above (in an interview with the Sun Sentinel, Florida in 2006), structures can be designed to withstand 250mph (402 km/h) wind speeds, however this would be very costly and tend to exceed the average income range of most people in the Philippines. In the United States for example, the most stringent design code, the Miami-‐Dade County Code, assumes a design wind speed of only 146 mph (235 km/h) and the Federal Emergency Management Agency, FEMA’s approach to the tornadoes exceeding 110 mph (177 km/h) wind speeds advocates the use of storm shelters / safe rooms. It is possible to design buildings to withstand these extreme wind speeds, however the cost of such an undertaking together with the lack of frequency of such powerful typhoons like Yolanda, are major deterrents in investing in such rigorous designs. Figure 6 – Enlarged scale of the path of Typhoon Yolanda (Haiyan) in the Region
9 http://earthquake.usgs.gov/aboutus/docs/020204mag_policy.php 10 http://www.fastcodesign.com/3021580/innovation-‐by-‐design/is-‐it-‐even-‐possible-‐to-‐design-‐buildings-‐that-‐can-‐withstand-‐250-‐mph-‐typh
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Figure 7 -‐ Landfall path of Yolanda across the Philippines
Typhoon Yolanda made its first landfall in Guiuan, Eastern Samar at 4:40am on Friday, 8 November, 2013. Prior to impacting the Philippines, the Japan Meteorological Agency (JMA), which uses their own techniques for estimating typhoon strength based on satellite imagery, recorded the maximum 10-‐minute sustained winds at 230 km/h (145 mph) and the Hong Kong Observatory registered it at 275 km/h (170 mph). Provided the intensity continued without change, this would make Typhoon Haiyan the strongest Typhoon at landfall based on wind speeds, surpassing the record of Atlantic Hurricane Camille in 1969 of 305 km/h (190 mph).
Tacloban City
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Figure 8 -‐ Sattellite image from http://climatex.ph which showed Tacloban City lying directly in the eyewall of Typhoon Yolanda(Haiyan) when it made landfall at Tolosa-‐Dulag
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Tacloban City Eastern Visayas or Region VIII with an overall population11 of about 4,101,000 (taken from the 2010 population census), was the most severely impacted region in the Philippines. Tacloban City, which is the capital and government seat of Region VIII, contained the largest population of Eastern Visayas, with approximately 221,174 persons. It was ranked as one of the fastest developing cities in the Philippines and it was the first city in Region VIII to become a “Highly Urbanised City”. Tacloban was also briefly the capital of the Philippines, from 20 October 1944 to 27 February 1945. Figure 9 Figure 10
11 http://www.citypopulation.de/Philippines-‐UA50.html
Tacloban City
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Impact of Typhoon Yolanda on Tacloban City The second point of landfall for Yolanda after its initial impact at Guiuan, was Tolosa and Dulag in Leyte. This puts the eye of the cyclone about 24-‐29km from Tacloban City. The most severe impact of Typhoon Yolanda (Haiyan) was estimated to be within 50km, either side of the eye, as illustrated by the red strip in Figure 5 below. Tacloban City contained the highest population of places that were impacted within the Typhoon’s path through the Philippines. Figure 11 -‐ Distance from Typhoon Path and Population
Tacloban City
Tolosa and Dulag
Guiuan
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Wind Impact There are no definite readings for the wind speeds of Typhoon Yolanda (Haiyan) during its onslaught on Tacloban City. However using the following data, the assumed maximum sustained 10-‐minute wind speeds experienced in Tacloban would be within the maximum wind speed zone of the Typhoon, which was about 265-‐275 km/h from the readings just prior to first landfall in Guiuan. This estimate is based on the following data and assumptions:
Correlations using the wind and pressure fallout graphs for typical cyclones, shown in Figure 6 Tacloban City was about 29 km from the eye The cyclone experienced consistent intensity following its initial landfall at Guiuan
Figure 12 -‐ Pressure and wind speeds fallout from the eye of a hurricane/typhoon
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Storm Surge The storm surge resulted from the typhoon traveling from East to West through the Philippines with winds revolving in a counter clockwise direction, forcing a wall of water into San Pedro Bay, shown in Figure 7. This culminated in Concabato Bay which bottle necks between Tacloban City and the island of Samar, resulting in the complete devastation of thousands of homes in Tacloban. Figure 13 -‐ Wind direction of Typhoon Yolanda traveling through Samar and Leyte Islands in Philippines
The storm surge heights recorded across Tacloban varied from as low as 3m to as high as almost 9m in some areas. The Daniel Z. Romualdez Airport was devastated by a 4-‐6m high storm surge and observations of water level marks on buildings inside Tacloban City estimated storm surge levels exceeding 8.5m.
Concabato Bay
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Figure 14 -‐ Storm surge height estimates based on observations by Hal Needham12
Based on the extent of damage observed, the surge extended as much as 500-‐700m inland in some areas, particularly in the low lying area of San Jose, and resulted in these areas being inundated for up to 4-‐6 hours after the event. The following figure highlights the areas where structures were totally, highly and moderately damaged. Some of the areas highlighted in red were areas that were directly impacted by the storm surge.
12 http://stormsurge2010.blogspot.com/ accessed 21/02/14
Daniel Z. Romualdez Airport
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Figure 15 -‐ Extent of damage of structures in Tacloban following Typhoon Yolanda
Deltares, a coastal engineering group in the Netherlands, developed an animated simulation of the typhoon winds funneling water up to San Pedro Bay, which resulted in the catastrophic storm surge in Tacloban. http://www.youtube.com/watch?feature=player_embedded&v=8SH5fhGYCm0 This video below was taken by a humanitarian aid worker from Plan International which taped the storm surge from a rooftop of a building in Samar. http://www.youtube.com/watch?feature=player_embedded&v=rS0gv4Xbw7w
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Rainfall In addition to being assailed by forceful winds and a cataclysmic storm surge, there was also significant rainfall. Tacloban experienced about 400-‐440mm of rainfall, recorded during the period of midday 6 November to 9am on 9 November. This exacerbated the flood water levels, contributed to structural damage due to hydrostatic pressures and nonstructural damage due to water ingress. Figure 16 -‐ Accummulated rainfall during the period of impact of Typhoon Yolanda
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Hospitals in Tacloban There are seven hospitals located in the city, all of which sustained from moderate to significant degrees of damage in the typhoon. Only two of the seven are public hospitals and these are:
The main referral hospital, Eastern Visayas Regional Medical Centre (EVRMC) Tacloban City Hospital.
The other five facilities are private hospitals offering varying medical care services. These are:
Divine Word Hospital Bethany Hospital Tacloban Doctors Medical Centre Mother of Mercy Hospital Remedios Trinidad Romualdez Hospital
Figure 17 – Google Map of Tacloban City highlighting seven main hospitals
Only three of these facilities will be described in more detail in this Section. These are the facilities where most of the WHO emergency repair activities were focused, during the period of November to December 2013.
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Eastern Visayas Regional Medical Centre The main hospital complex consists of six two-‐storey and one single storey reinforced concrete buildings housing wards, emergency rooms (ER), operating theatres (OT), Labs, intensive care units (ICU) and other medical facilitites. There are also numerous single-‐ and two-‐storey service buildings spread across the compound housing the laundry, morgue, kitchen, accommodations, maintenance department, desalination plant, stores and waste water treatment plant. The roofs consisted primarily of structural steel hip roof frames and steel cee purlins with galvanised sheeting. The hospital capacity prior to Yolanda was 500 beds operating as a Level 3 facility. Figure 18 -‐ Drawing plan of EVRMC highlighting degree of damage post-‐Yolanda
Figure 19 -‐ Legend
The hospital is sited on the corner of the peninsula and is bordered by Concabato Bay. There is a rubble masonry sea wall, approximately 2m high constructed along the coast. The difference between mean sea level and ground level of the nearest hospital building is about 3m. Additionally there was a reinforced masonry boundary wall constructed along the rear of the hospital about 4m away from the coastline.
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Image 1 -‐ Elevated reinforced concrete tank There are 2 water storage tanks, an elevated reinforced concrete (RC) tank, storing 45,000 litres of water and two underground reserve tanks storing 65,000 litres each. For approximately 2 years prior to the typhoon, the hospital did not receive pipe borne water. 60% of the potable water supply was generated through a 100,000 litre/day desalination plant and 40% was from the treated grey water recycled back into the hospital. The average daily water usage of the hospital pre-‐typhoon was approximately 130,000 litres. The hospital had a complete tertiary level treatment of black and grey wastewater, with a capacity of 60,000 litres. The system was supplied by Varmet Engineering, Germany. As mentioned previously, 40% was re-‐cycled back into the hospital and the remainder was discharged directly into Concabato Bay.
Image 2 -‐ Rear of EVRMC showing the desalination and WWTP plants
The original 500kVA generator for the hospital was housed in a single storey, RC building at the rear of the hospital, adjacent to the elevated RC water tank shown in Image 2. This generator was destroyed in the storm surge. A new 375kVA generator was donated and installed by AECID, which consumed approximately 360 litres of fuel daily. The morgue located to the east of the compound, was a single storey reinforced masonry building housing refrigerator/ freezer room for 1-‐2 bodies, office, small change room, store room and autopsy room. The
Concabato Bay
Desalination Plant Waste Water Treatment Plant Plant
Approx. 4m
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damage from the typhoon which left this building, together with the rest of the hospital compound, submerged in about 1.2-‐1.5m of water for several hours, broke window panes and uplifted some of the roof sheeting, rendered the facility unusable. During the assessment there were up to eight bodies stored in bags outside of the morgue. The summary of damage observed at the facility included the following:
Approximately 40% -‐ 50% of the roof sheeting was lost together with some damage to purlins, particularly at the rear of the facility, close to the coast.
The storm surge, which almost topped the single storey buildings, left the entire facility with approximately 1.2 -‐ 1.5m of water which absolutely devastated electrical and mechanical equipment equipment, medical supplies, medical records, furniture, etc.
External glass windows and doors were almost totally shattered. The single storey peripheral buildings suffered significant damage which housed essential services
for the operations of the hospital. Approximately 30% of the rear boundary wall was toppled by the storm surge.
Illustrations of this damage, particularly structural impact, are highlighted in Damage Assessment section of this document.
Activities WHO provided the following support:
o coordination of materials (plastic sheeting from UNHCR) for emergency roof repairs and individual and family tents for the hospital staff who had also lost their homes in the typhoon
o installed a ‘rubhall’ (supplied by WFP) for the storage of donated medical supplies o trained pharmacy staff and implemented Supplies Management (SUMA) software to
monitor and control the medical supplies being donated during the emergency response o provided support in the coordination of the numerous activities at the hospital to ensure no
overlap occurred
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Figure 20 -‐ Drawing identifying the current and proposed activities at the hospital from various agencies
Mother of Mercy Hospital (Private) This is a 4-‐story reinforced concrete frame building, located approximately 700m off the coastline, at the base of the hills. It had a capacity of 100 beds before the typhoon and operated as a level 2 facility providing all general healthcare services. The hospital sustained damage to about 40% of the roof structure and framing. Steel trusses were lost together with the galvanised sheeting. Also about 10% of external windows and doors sustained damage either through shattered glazing or complete pull out of the wind frames.
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Image 3 -‐ Part of roof showing structural framing but loss of sheeting
The hospital was not affected by the storm surge, nor flood waters as the drainage channel at the rear of the hospital did not overflow. The generator room remained intact so the 500kVA generator was functional post-‐typhoon; however fuel was in limited supply. The morgue, located adjacent to the generator room, was also undamaged. As well as the medical supplies and records stored inside the main hospital building. Image 4 -‐ Drainage channel between the main hospital building and the morgue
There were 4 aluminium water storage tanks on the roof of the hospital and 2 of these were blown off with the typhoon winds.
Roofing screws still connected to purlins
Concabato Bay approximately 700m away
Large surface runoff drain, did not overflow during typhoon
Morgue sustained little non-‐structural damage, but non-‐functional due to loss of utilities
Housing for the generator
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Rain water ingress through to 2nd floor level hampered the functionality of the hospital and prevented use of the operating rooms, maternity rooms, etc. due to the constant dripping of water through the permeable floor slabs.
Activities In week 4 post-‐typhoon, 27-‐29 November, 2013 WHO with the assistance of the Philippine army
executed emergency repairs to the roof. Plastic sheeting, supplied by UNHCR, was used to cover the exposed roof trusses, the exposed floor slab where no trusses were available at roof level and the exposed window and door openings on the lower levels to make the hospital watertight and re-‐establish in-‐patient capability.
Image 5 Image 6
The german NGO Humedica was based at the hospital from 10 November, 2013, 2 days after the
typhoon struck. They assisted in making the hospital partially functional. They supplied on average 200 litres of diesel fuel daily to run the generator for 8 hours. Water was being accessed from a deep well and treated with filters and chlorine supplied by Humedica. The filter capacity was 50 litres per hour.
Bethany Hospital The hospital consists of five 2-‐storey and 3-‐storey buildings and several single storey structures at the rear of the hospital. The hospital originated in 1918 as an old wooden structure and expanded over the years to occupy four hectares of space. It had 150 beds before typhoon Yolanda and operated as a level 2 hospital. This facility is located within 150m off the coast and was severely impacted by the storm surge. The surge experienced by the hospital devastated the medical equipment, supplies and records all stored on the ground floor level. The hospital director noted that during the typhoon, there were several in-‐patients in the ground floor at the time and they had to be evacuated to the upper floor. No hospital staff or patients died. The storm surge brought with it, significant debris, including trees, vehicles and bodies that were deposited against the rear of the hospital and left approximately 1.5m of water on the ground floor of the entire compound, which took about 4 hours to recede. The reinforced concrete structure was undamaged.
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Image 7 -‐ Debris deposited with the storm surge behind hospital Image 8 -‐ Damage to wooden roof structure on older building
One of the older buildings had 80% damage to its wooden roof structure and sheeting. The other buildings lost approximately 40% of its sheeting. It was observed that the older wooden structures exhibited more extensive damage than the newer structures with steel rafters. The water tank was a reinforced concrete underground structure which was totally infiltrated and made unusable after the storm surge. Image 9 -‐ Bethany hospital after significant debris clearing
Activities WHO provided coordination for clean-‐up operations from ILO and UNDP, collection and proper
disposal of medical waste from UNDP and materials for emergency roof repairs from UNHCR. Medecins Sans Frontiers (MSF) France set up a field hospital in the parking lot of the hospital with
surgical capacity, cold chain for 150litres and in-‐patient capability. They provided support to get the operating rooms in the hospitals operational, provided generators and fuel and repaired the hospital autoclave, among other restoration activities.
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Damage Assessment The damage observed post-‐typhoon was as a result of one of-‐ or a combination of the following:
Wind forces Storm Surge Heavy rainfall
The powerful typhoon winds produced damage due to the following actions: Hydrodynamic forces
o Suction and pressure forces o Uplift
The storm surge produced damage to structures and homes due to the following actions: Hydrostatic forces
o Lateral fluid pressure o Vertical buoyancy effects
Debris o Impact of large water-‐borne objects (cars, trucks, building fragments, trees, ships, etc.) o Damming (filling of openings with debris, increasing the effective area experiencing lateral
load) o Increase in flow viscosity/density due to collected smaller debris/sediment
The high intensity rains also contributed and produced similar effects to the storm surge, but to a much lesser extent. Much of the damage observed was as a result of a combination of these actions, and not necessarily associated with one individual effect.
Wind Image 10 -‐ One of the 2-‐storey buildings of Bethany Hospital
Main timber rafters intact, however timber purlins and roof sheeting lost due to wind uplift forces – which may have magnified due to increased internal air pressure from damaged windows Non-‐structural damage – window panes shattered and blown off
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Image 11 -‐ Structural steel and galvanised sheet roof of the Astrodome
Image 12 -‐ 4th floor and roof of Divine Word hospital (private facility)
Image 13 -‐ Damage to roof sheeting at Bethany Hospital
Structural frame remained intact, however glazing in the roof shattered and some of the galvanized sheets torn off. It appears that some of the failure may be due to shearing of the roof sheets since partial sections of the sheets are missing.
Line of glazing under elevated centre roof.
Window frame and connections completely removed from structural walls
Non-‐structural damage wind and rain rendered this floor non-‐functional.
Lost over 60% of the roof sheeting, however structural frame and purlins undamaged.
Stainless steel gutter straps
Partial uplift of roof sheets, either due to bolt failure or shearing of the galvanised Sheets around the bolt connections
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Image 14 -‐ Damage to roof structure on the end bay of the gable roof – Bethany Hospital
Image 15 -‐ Buckling of structural members
Wind direction
Given the wind direction, this portion of the gable roof would be subject to the highest uplift suction forces. Timber truss frames, rafters and roof sheeting taken off.
Note direction of branches on coconut trees
Out-‐of-‐plane failure of apex of gable wall, unable to observe reinforcement in the wall from this distance
Entire roof frame buckled
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The images below are of two of the buildings at the main referral hospital in Region VIII, the Eastern Visayas Regional Medical Center (EVRMC). These buildings located along Concabato Bay all exhibited similar degrees of wind damage: with approximately 40-‐50% of the roof sheeting being uplifted, purlins buckling close to the eaves on the windward end of the building and glazed windows and doors shattering. Image 16 -‐ Rear of one of the buildings at EVRMC Image 17-‐ Wind damage to the roof of another building at EVRMC
The next few images are of various buildings in Palo, which is the neighbouring province to Tacloban. There was no storm surge this far inland, where these buildings are located; however the damage due to the wind was extensive. Image 18 -‐ Leyte Provincial Hospital, Palo
Structural damage to the steel framing and almost complete loss of roof sheeting.
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Image 19 -‐ Close up of Building shown in previous image
Image 20 -‐ Factory located on the border between Tacloban and Palo
Image 21 -‐ Storage warehouse in Palo
The following three images are of a Call Centre building in Palo that was said to have been used as a temporary shelter during the Typhoon. The connections of the long-‐span trusses failed on one of the two
Complete pullout of glazing frame. Note vacant bolt holes in the RC structure.
Buckling of roof trusses and purlins and frame of enclosure cladding
Almost complete loss of roof sheeting. Structural frame remained intact.
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supporting ends, and the lack of redundancy resulted in catastrophic failure of the roof structure. The slender reinforced concrete columns on both longitudinal side elevations of the building, which framed large glazed openings, also failed. Image 22 -‐ Call Centre building in Palo Image 23 -‐ Buckled long-‐span roof trusses
Image 24 -‐ Failed support of the roof structure
The following three images illustrate the failure of an open air, trussed portal frame structure that was located in the courtyard of the Department of Health (DOH) facility in Palo. The trussed stanchions utilised welded connections to angle cleats that were also welded to the base plate on elevated reinforced concrete pedestals. The integral welded connections at the base of the stanchions failed. In some instances the entire angle cleat to base plate welds failed and in some cases the base stanchion to angle cleat welds failed. The bolted connections remained intact. The failure at the base of the columns resulted in collapse of the frames and subsequent buckling of the connecting members between frames.
Note the height of the backhoe (estimated at about 4m or 12 feet) to the overall height of the structure.
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Image 25 -‐ Failure of welded connection between stanchion and angle cleats
Image 26 -‐ Stanchion completed absent from base plate
Image 27 -‐ Collapsed, buckled frames of the trussed portal structure
Welds connected to either side of the angle flanges of the stanchions.
One flange connection failed and the other remained together, resulting in distortion of the angle cleats
Angle flange
Bolted baseplate connection undamaged
Entire welded connection around the angle cleats failed. Note the amount of corrosion on the baseplate; this implies that the entire perimeter around the angle cleats were not sealed by welds, or that the welds may have also been significantly impaired by corrosion.
Welded connections between stanchions and rafters stayed together. The only observed failed connections were the welded connections at the stanchion bases.
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Combination Storm Surge and Wind Image 28 -‐ Daniel Z. Romualdez Airport post-‐typhoon
Image 29 – Aerial photo of D. Romualdez prior to establishing partial functionality
The air traffic control tower bird’s eye structure lost most of its external glazing due to wind forces and the runway lights and towers were all destroyed, rendering the airport non-‐functional for a number of days following the impact of Typhoon Yolanda. The following two images are taken of part of the boundary wall damage at the Divine Word Hospital. This area where this hospital is located in Tacloban City, only experienced about 0.3 to 0.6m (1-‐2 feet) of storm surge. This compounded with hydrostatic pressures from rainfall, may have caused the overturning of part of the reinforced masonry boundary wall. The foundation level of this wall was only about 0.45m (1’-‐6”) below ground.
Damage to roof sheeting and façade elements due to wind forces. Entire non-‐structural glazing destroyed Storm surge heights estimated between 4-‐6m – a combination of hydrostatic pressure and the impact of water-‐borne debris destroyed the glazed external envelope to the terminal building and caused extensive damage to all internal functional elements.
Uplift of roof sheeting
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Image 30 – Bird’s-‐eye view of the boundary wall Image 31 -‐ Close up of the failed section of the wall
The following images highlight the ruinous damage to the temporary style homes erected along the coast. This low-‐lying area was directly impacted by the storm surge which flattened houses and trees and transported large debris including trucks and chunks of concrete walls. Image 32 Image 33
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Debris Impact The images below are of one of the 10 commercial ships that washed inland with the storm surge in Tacloban. This ship resulted in complete obliteration of the temporary style, timber homes in which it came into contact with, in the coastal village of Anibong District, Tacloban City. Image 34 Image 35
Image 36
At the time of writing this report, the ship still had not been moved, only propped on the unstable rubble below and residents had started re-‐building their homes in this village – in a similar manner, prior to the typhoon.
3000-‐ton cargo ship ‘MV Eva Jocelyn’ deposited inland with the storm surge
Timber homes being re-‐built with timber recycled materials found in the rubble
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The following images further highlight damage resulting from debris impact. Image 22 illustrates water-‐borne debris deposited at the rear of Bethany Hospital from the storm surge. This resulted in damage to windows and doors and the ingress of water and debris into hospital and likely the increase in water pressure due to damming; however the robust reinforced concrete structural frame remained undamaged. Image 23 shows a car sitting over the rubble left of temporary style homes highlighting the structural damage due to the impact of large water-‐borne debris. Image 37 – Rear of Bethany Hospital Image 3813 -‐ San Jose
The images below show the potentially catastrophic damage to adjacent structures from fallen electrical poles. Note, due to the failure of these poles, Tacloban City and much of the region lost electricity for almost 2 months following the impact of the Typhoon. Image 39 -‐ Fallen electrical poles Image 40
13 Image: http://www.salon.com/2013/11/11/10_major_challenges_facing_the_philippines_post_haiyan/
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Non-‐Structural Damage This section highlights some of the non-‐structural damage observed, such as the damage of external façade and the ingress of flood waters from storm surge and driving rain that would have severely impacted the outfitting of the buildings and rendered them non-‐functional. Image 41 -‐ Interior of Bethany Hospital at ground floor level
Image 42 -‐ Third floor front curtain wall of Tacloban City Doctors Hospital
The next two images show the damage resulting from the impact of storm surge waters on the desalination plant for the Eastern Visayas Regional Medical Center (EVRMC). The height of the storm surge topped this single-‐storey building, which was located about 10m away from Concabato Bay. The desalination plant, prior to the Typhoon, produced approximately 100,000 litres of potable water. This amounted to about 60% of the total daily water consumption of the hospital.
Water level mark from the storm surge, at least four feet high. This completely destroyed medical supplies and equipment, together with utilities such as electrical wiring and sockets that would have been submerged in the flood waters.
Over 70% of the glazing on the front elevation of hospital was damaged. The glazing was not laminated; note the jagged edged of the shattered panes.
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Image 43 -‐ Damage to the desalination plant at EVRMC Image 44 -‐ Damage to piping and electrical
The other 40% of the potable water daily usage at EVRMC was generated from the tertiary sewage treatment plant. This facility was located adjacent to the desalination plant (illustrated above) and the damage resulted from the storm surge. The ground floor level of this building was about 3m above mean sea level, while the height of the observed damage on the elevation of the sewage treatment facility is about 3.5m. This puts the estimated storm surge height in this area at about 6.5m, not accounting for actual tidal levels or wave action on the top of the storm surge. Image 45 -‐ Rear of the waste water treatment plant structure
The steel structure was undamaged; however the insulated cladding panels were ripped open with the hydrostatic pressures.
Desalination plant building adjacent
Reinforced concrete boundary wall at the rear of the hospital overturned and failed out-‐of-‐plane with the storm surge impact.
≈3.5m
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Image 46 -‐ Reactor drums and piping damaged inside the facility Image 47 -‐ Further damage of sewage treatment apparatus
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Impact on People The impact of such events are disastrous, not only to infrastructure, but to the lives of the country’s inhabitants in the immediate and long-‐term development and recovery. Image 4814 -‐ Views of Tacloban City on November 10
14 Image http://minnesota.publicradio.org/display/web/2013/11/09/photos-‐typhoon-‐slams-‐philipines
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Residents of Tacloban were required to queue for hours at the various food and water distribution points. Image 49 -‐ Young Filipinos with supplies from food collection Image 50
Image 51 -‐ More bodies being discovered as debris is cleared from streets in Tacloban. Photo taken 4 weeks after Typhoon
Water and Sanitation, food supplies and medical care were of paramount importance at the various shelters where thousands of families sought refuge. The difficulty to mobilise resources, failure of the pipe-‐borne water system and other utilities after Yolanda’s impact meant the conditions at many shelters quickly decayed into poor sanitation.
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Image 52 -‐ Astrodome shelter, housed up to 1000 families Image 53 -‐ San Jose shelter, housed up to 500 families
Conclusions The predominant damage observed to structures was to the roofs, with loss of sheeting and damage
to structural framing, and blown out windows and doors, which is consistent with the expected observations post-‐typhoon. More catastrophic destruction was observed in areas subjected to the storm surge.
o In terms of some of the construction practises observed, the reinforced concrete structures adhering to the national building code, performed better under the imposed typhoon wind and storm surge action, as compared with lighter framed timber structures.
o The temporary style homes, likely illegal housing, constructed along the vulnerable coastal zones were not designed to any recognized safety standards or codes and the construction using nailed timber and unreinforced concrete or masonry materials were not adequate to withstand the impact of the storm surge or wind actions. Also, the high-‐density occupancy posed a serious threat to the people living in these areas, who were not evacuated prior to the typhoon.
Many facilities selected as shelters, typically schools and the Astrodome, which was the largest shelter in Tacloban, sustained significant damage to roofs and fenestrations. This would have resulted in unsafe conditions with the evacuee families being exposed to the elements.
The main referral hospital, Eastern Visayas Regional Medical Centre, sits astride Concabato Bay in a location that was highly vulnerable to the storm surge impact. A section of the reinforced masonry boundary wall collapsed under the hydrostatic pressure, which exposed the hospital facility to even further damage.
In several cases where roof sheeting was lost it was observed, particularly at EVRMC and Mother of Mercy Hospital, that the galvanized sheets sheared around the screws and that the screws remained connected to the steel roof purlins.
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Recommendations Proper urban planning to reduce the vulnerability of communities residing in high risk coastal zones.
Review the current relevant public regulations taking into account the history of natural disasters to diminish the impact and loss of lives in future such event by prohibiting the construction of homes and restricting the types of buildings allowed to be constructed along the vulnerable coast. It should be noted that, almost 101 years prior to Haiyan (Yolanda), on 26 November 1912 a severe typhoon and accompanying storm surge swept across Visayas, Philippines and almost flattened Tacloban and Leyte, killing an estimated 15,000 persons.
The minimum design wind speed specification in the NSCP2001 should be deliberated on, given the frequency of impact of typhoons with wind speeds exceeding 3-‐second gusts of 250 km/h, especially to critical infrastructure that need to remain functional during and following the impact of typhoons, such as airports, hospitals, shelters and ministerial buildings. This increased requirement would have cost implications that would also need to be carefully measured and prioritised.
During deployment in Tacloban, Government officials cursorily discussed the possibility of siting a location on higher grounds, away from the coast, to move the Eastern Visayas Regional Medical Centre. In the interim, strengthening the facility to better withstand typhoons should be considered, including the following:
o Install laminated glass, able to sustain the impact of flying debris on all external glazed fenestrations of the buildings.
o Construct of a storm surge barrier along the boundary of the hospital compound. o Strengthen the roof structure, inclusive of all materials and connections. o Medical supplies and records should be stored in secure buildings and possibly relocated to
higher ground to mitigate potential losses in such events. Review the current design and construction of roofs. Emphasis should be placed on:
o roofing materials – strength of sheeting materials and purlins o pitch and geometry of the roof o Connect sheeting securely from the crest of the corrugated galvanised sheets through
timber inserts with stainless steel screws and washers.
