Pakistan Earthquake: Introduction to Disaster Risk and Seismic Mitigation for Non Engineered Structures

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Introduction

On the 8^th of October 2005 tragedy struck the Kashmir region of Pakistan as a massive earthquake claimed more than 80,000 lives and left 3.5 million injured or homeless. But could such a humanitarian disaster have been averted? In developed countries in earthquake zones the impact would not be so extreme. However in the developing world, especially in Kashmir, vulnerability to hazards is much greater and can lead to greater loss of life.  The quake strung on a school day. 17000 children were killed in total from the collapse of 7000 schools. The earthquake served as a tragic indictment of poor building standards. Could this be prevented with seismic mitigation in non engineered structures? Robin Cross, director of projects at Article 25 believes so.

Above: Childrens play equipment amongst ruins.

He led the A25 response to the Kashmir earthquake. Like any normal Architecture project this was conducted with same professionalism and structure as you may be working on now. It began with a feasibility study and investigation of the context. The study revealed why loss of life was so high and how in future this could be prevented

Feasibility Study

Above:  Collapsed structures

Concrete buildings meant prestige to the people of poverty stricken area. Therefore when given the opportunity to move from outmoded vernacular homes into a concrete structure there was no hesitation. Yet it was these very same concrete structures that collapsed with little resistance. In fact studies showed that vernacular style homes stood up well by comparison.

Population growth was also a factor and led to more homes built in an unsustainable manner on marginal plots. Homes were perched precariously on hillsides or in the shadow of unstable deforested hillsides. If they didn’t fall down the hillside many homes were wiped out by massive landslides. In one such case the side of mountain gave way resulting in a landslide that killed 575 member of one community in a matter of minutes.

Above: The assesment of collapsed structures

The feasibility highlighted the tremendous flaws in land use and planning that resulted in an increased loss of life. It also highlighted the lack of education and knowledge there is amongst these communities regarding earthquakes. It was clear that there was action for A25 to take.

Approach

Action focussed on a bottom up approach that engaged with the afflicted communities. This approach would allow for better understanding of the requirements of the community rather than a quick deployment of an imposed and unsustainable solution. It has been the case with some disaster relief efforts that not enough consideration has been given to finding what is the right solution. Now, if this was a business or investment issue, the right solution could be found in investools. But it was a different matter so finding the right solution could be a bit challenging.

As I wrote in my introductory article “Article 25 aims to work themselves out of a job”. Therefore A25 took the approach of designing a simple vernacular building system that could then be replicated by the community. So the approach was two fold. Establish a design solution and then empower the community to continue the progress. They also were able to provide education about earthquakes.

Initial Design

The study of design options considered the following:

• Bhatar type construction
• Reinforced masonry type construction
• Confined masonry type construction
• Dhaji Daweri (timber frame) type construction.

Based on local conditions the Dhaji Daweri was seen to be the best and following community consultation became widely accepted as the best method. You will recall that concrete was the prestige material and that a return to the Dahji Daweri was considered a step back. However the construction of prototype homes proved a success.

Above: A prototype dwelling

This construction also benefited from:

• Lighweight timber frame which was good for the transportation of materials
• Timber could be salvaged from collapsed structures
• Transport of materials was easier than heavyweight materials especially in very remote mountainous areas of Kashmir.
• Local stone could be used as infill panels
• Communities could easily engage with methods and be trained in construction techniques.
• It suited the local vernacular
• The structures were designed to with seismic protection in mind.

Above: The timber construction

Construction

An architect volunteering with A25 oversaw site operations on site. They had a team of engineers from the aid partner MuslimAid. The engineers were given training which could then be passed on for use in Kashmir and in other areas of the world; an extension of the empowerment that A25 are so keen on.

The homes were built on a concrete foundation that met government standards. The foundation was also made deliberately larger to allow for future expansion of the homes. Future proofing was seen as a good way to maintain standards in the future.

The structure was built from timber. It consisted of small members and bracing that could dissipate the effects of a quake. The effect of a quake would result in cracking but not to the extent that collapse would occur unlike concrete structures. Again models were used to demonstrate the construction of joints to community builders and the engineers.

See more images

Evaluation

A25 delivered the new homes to the community in the first instance and provided skills and empowerment to enable them to build on. As a response to disaster relief they have extended the remit of the disaster relief agency and by virtue of the methodical architecture driven approach have left lasting and seismically strong buildings.

Robin Cross wasn’t shy in admitting areas of improvement for these projects. He stated that thermal performance needed to be looked at and would be considered in revised designs. Scale of delivery was god and now there is a basis to offer improvements such as an insulated roof.