A team from the Indian Institute for Human Settlements visited Kathmandu and a few neighboring villages in the week between the two earthquakes of April and May 2015. This note is based on the quick assessment that was made right after and presented at a few conferences and public foras in the last few months, in the hope that better planning in Kathmandu, and many other places around the world that are exposed to external hazards, can save them from disasters.
The key research questions we started the mission with included:
1. What are the key causes of damages, and what can be done to abate them in the future?
2. How can we build people’s capacities and knowledge about earthquake-resistant building technologies? And yet, how can we ensure proper shelter for the displaced people before the upcoming monsoon season?
3. How can we strike a balance between building new houses and toilets in the immediate future and long-term building stock resilience in Nepal?
4. What are the gaps in planning instruments and their implementation?
While walking around the city, we could notice that while many structures had fallen off, many remained intact. It was only curiosity that led to connecting the dots between the damaged structures, to know why they failed and others didn’t. This piece outlines the resulting Rapid Visual Damage Assessment done leading into a needs assessment.
TYPES OF DAMAGES
There was a typology or pattern of damages that was observed, described with some illustration below:
D1 – Differential sinking
Many buildings were seen to have collapsed due to partial or complete sinking of the land below. When mapped together, it is easy to see that many of them were located on what used to be the flood plains, wetlands, and soft sub-soil conditions and technically development should not have been allowed in those areas. When searching for a soil quality map of the city, to overlay on this map, one could not be located. In the absence of such information, how does the city plan its future construction? In such soil conditions, additional structural measures must be taken (if at all buildings are allowed to be built) with tie beams and floor beams, but unless such areas are demarcated differently, it is difficult for people to know and adhere to any requirements. The cities need to have a detailed soil map with zones clearly demarcated (at least 5mx5m resolution) and building codes should be made per zone.
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D2 – ‘Soft storey’ failures
Many buildings were seen collapsed with a sole cause being ‘soft storey’ construction. For the uninitiated, when a building is constructed with no walls and only columns, it lends less rigidity to the structure and is deemed to be inappropriate for seismic locations. Kathmandu being one of those, should not have approved such constructions. But then Kathamndu is not unique in that. Cities like Delhi, also located in seismic Zone 4, required by law (a.k.a. building bye-laws) to build most new residential and commercial structures to be built on such soft storeys to provide for adequate parking. This is a regulation completely devoid of any understanding of risk, and only attempts at addressing a problem that is caused by other reasons (ease of buying and owning cars, etc.) This is a systemic problem and can take an entire city down in case of an event, which could have been easily avoided with better integration of risk mitigation measures in the building bye-laws.
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D3 – Poor quality concrete framed structures
Concrete construction is only a few decades old and comparatively a recent phenomenon in Nepal. This might explain why many masons and contractors are probably unaware of the right techniques for the use of steel and concrete. Right after the earthquake, when the debris was still present on sites, many buildings were seen with poor quality construction practices. This included large stirrup distances, insufficient overlaps in steel and insufficient torred steel sizes. Poor concrete mixes leading to honeycombing effects were also seen in many instances. Poor structural designs were determined with heavyweights on cantilevers and in many cases cantilevers resting on no beams. Most of these can lead to partial or complete building collapses. Poor quality brickwork and mortar were also noticed, although these mostly only lead to cracks, but can still be fatal to people living in or around such structures. Many multi-story structures were also seen with serious cracks and damages, although none had collapsed entirely. This is not necessarily an outcome of bad building codes, but poor implementation and monitoring. This needs to improve substantially, and rather quickly as many people have started rebuilding already, recreating the same mistakes again.
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D4 – Poor quality mud mortar structures
All construction was using mud, timber and clay bricks for the longest, until a few decades ago when many aspired to have concrete structures. While most mud-mortar structures have collapsed anyway, the ones that have led to greater life and material loss are the ones that were a combination of mud walls and concrete slabs. Heavy concrete slabs were seen to have fallen flat, taking down anything below with them. The walls were unable to support the weight on top of them, more so as they lacked sufficient intermediate columns. While in the villages where most construction is still in mud-mortar, concrete structures are not much of an option (at least in the short term) because access to material is very difficult. Many villagers were seen to be collecting bamboo from the neighboring sites and rebuilding what they could. But with better knowledge and training, and use of cross beams in walls amongst other practices, bamboo and mud could be used as much more resilient construction materials as being tested and promoted by many scientific NGOs.
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D5 – Differential bulging of soil/liquefaction
Liquefaction is a phenomenon in which the strength and stiffness of soil are reduced by earthquake shaking or other rapid movements. In many cases, the soil below the buildings looked like it experienced liquefaction, and bulges on the ground could be seen in many parts of the building. Undermining the foundations and base courses of the buildings can lead to liquefaction causing serious damage. Areas which are water-saturated, or with unconsolidated sediments can lead to such outcomes and must be treated with additional care at the time of design and construction.
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D6 – Bulging of walls
In many instances, walls on the lower floors were seen to bulge with the load on top. Predominantly in mud wall structures, but was also observed in many brick and mortar structures as well. This is potentially due to insufficient column sizes and distances, and overloading of the structure. In many locations, people had used props to support such bulging structures temporarily, but the hope is that many were brought down before the second massive quake in the following week.
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D7 – Dangerous design elements
Many buildings were also seen to have poor design features such as overhead water tanks on single columns, column-free corners (3-4 story cantilevers), false walls as add-on false walls on facades with insufficient cross tying. Such elements should not be approved at the design level, as well as monitored closely at the time of construction completion.
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D8 – Other types of damages
Boundary collapses were common as most of them used unburnt clay bricks, insufficient spacing columns or reinforcement, and bad joinery details. These may not have led to any serious direct losses but can cause serious disruption for access roads and emergency service delivery.
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Many instances of open wires and electric pole failures were observed across the city. This is primarily as electric poles are non-structural in nature, with an overload of wires on them.
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There were also cases where fire had broken following the quake. Usual causes were electric shortcuts, gas cylinder bursts, or combustible substances coming in contact with potential fuel (wood, fabric, etc.).
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These instances can be reduced with proper public awareness and precautionary measures taken by all individuals, families and commercial enterprises.
SPECIAL MENTIONS
“The Curious Case of 100 houses”
There’s a case of a housing development, next to a dried water channel. The development is less than 5 years old, but almost all structures have suffered severe damages. Why? What went wrong? There could be many reasons, but some that seemed to have evidence included multi-level construction with potentially insufficient ground leveling measures, uneven foundation levels leading to partial settling, questionable quality of construction and ground ramming. This is a case where almost all the above types of damages were observed, all in one location. The question arises as to why was the development located where it was, what was the process undertaken for design approvals, why was the quality of construction poor despite people having paid matching market rates, and what access did most people have to insurance as a means to recovery? This also leads to further questions with regards, what is safe failure, and how can that be incorporated in physical infrastructure?
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Schools and other social infrastructure
Many primary, secondary and higher secondary schools were damaged to a large extent – most of them being fully or partially constructed in mud mortar. Many vocational institutes were also damaged. Many students had lost their books and certificates. This is worse, as this was also the time for Indian graduate level competitive exams, and many potential applicants from Nepal are likely to have lost the chances to apply, while their families might be busy recollecting the missing pieces. There needs to be a special support or offering for the students hailing from Nepal such that they don’t lose a precious year if their lives.
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Heritage Structures
Heritage sites like Bhaktapur and Patan, which formed the back bone of the cultural and social space for the locals, were severely damaged. Palace precincts had also suffered sever losses. Many other temples, shrines, old libraries, etc. have also suffered irreparable damages. There’s extensive work being done by UNESCO and other agencies in recovering pieces from the rubble, that need special care and protection in the time of crisis and protected from vandalism and theft. Bringing these areas back will be critical for bringing back normalcy to the people of Nepal.
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Roads and infrastructure
While some of the major roadways have suffered severe damages due to partial sinking of the ground, many bridges across the city have remained intact.
Rebuilding in a week
People had begun rebuilding in the first week itself, using recovered material from the debris and similar construction techniques as before. Many had started filling visible cracks with plaster in an attempt to hide what could be more severe structural damages. Special attention needs to be taken immediately so the same mistakes are not repeated, and risks are not recreated.
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SUMMARY OF INTERVENTIONS
There is an observable pattern in the kind of damages that were noticed which can be mitigated in the future if better planning approaches are taken in time. Leading from the above analysis of the types of damages, following potential actions must be taken for reconstruction:
Planning Interventions
- Collect systematic information about soil types in the city, and identify zones for silt and black cotton soil. These zones must require special building codes.
- Zones close to river beds must be prevented from building construction, or must require special building codes and FAR regulations
- Underground aquifers must be mapped, and dried aquifers must be treated. Load bearing capacities of such areas must be tested and incorporated in soil zonation plan.
Building code and monitoring
- New building codes to be in place incorporating earthquake resistant techniques and use of local materials. Building sample structures in different zones maybe a possibility to build awareness.
- Besides building plan and structural drawing approvals, regular monitoring of construction site along with progress and completion reports
- Pre-mix concrete could be made available to standardize quality of concrete mixes
Capacity building and awareness
- People using old material to rebuild, with same old technology and knowledge. Dangers of rebuilding risky structures : Training for constructing earthquake resistant housing using local materials available, especially in villages. Contractor, mason and labor training programmes for construction techniques could be very useful.
- People need to made more aware of what to do in case of such an event, and what are the fire safety measures to be taken at all times
Early action
- Labor rates and material prices are likely to increase substantially, especially as many laborers come from neighboring villages and material from other countries like India and Bangladesh and could took advantage of the surge in demand. There’s an immediate need to manage and regulate labor and material prices, along with rebuilding damaged brick kilns.
- Rebuild villages to help the city – most people who work in the city, live in the villages, and unless their homes are brought back to safety, it would be difficult for them to get back to work – without pushing their families to help sustain themselves in the villages without their support.
- Interim shelters could become shanties in the long run. Need to replace the temporary shelters with permanent ones soon, particularly before the monsoons.
Although not in the ambit of this research, but here are additional mentions of socio-economic aspects for long-term recovery which we came across over various discussions and reflections from previous experiences. These need just as much attention in the short to mid-term for complete and sustainable recovery:
- As noted above, schools have fallen apart. They need to be rebuilt soon, to not just save students time but also expedite psychosocial normalcy
- Provision of clean water and toilets is absolutely necessary as the slow gains of building toilets in the last decade have now been set back. If not done in advance of the monsoons, could lead to other health hazards.
- Sex-trafficking has long been a battle in many parts of Nepal and now that many more women and children are being pushed into temporary shelters with ever high vulnerabilities, it may become easier to lure them with work and other resources to across the borders. Particular attention is required to protect them from such inhuman actions.
- It is learnt from other experiences such as in Haiti, that too much relief can lead to growing dependence, which in turn could be a hazard for long term recovery. There needs to be a solid exit strategy by all he donors and funding agencies currently working for aid.
- While the National Government is doing all that it could, other international agencies also need to recognise their leadership and work in coordination with them for a more holistic recovery and long-term resilient outcomes.
The team that went to Nepal consisted of the author along with colleagues Teja Malladi and Kunal Deshpande. The thoughts shared above are solely the authors and not representative of the organisation or other individuals. The author is particularly grateful to Sraddha and Namrata and their families for being immensely helpful hosts and Pranita for making the connection. The author would also like to thank Kumar Dhamala and all the other experts we met during the course of our stay for all the insights that they shared with us.
This article was written and published on 22 May 2015. Any new information hence may not be updated.
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