Earthquake Resistant Housing for Pakistan
AIT Dr. Pennung (left) Joins a Technical Team for Survey Trip of Earthquake Affected Areas in Pakistan
Habitat for Humanity® International (HFHI), in response to the October 2005 earthquake that killed over 80,000 people and leveled towns and villages across northern Pakistan, assembled a technical team of engineers and earthquake experts including Dr. Pennung Warnitchai, Associate Professor in AIT’s School of Engineering and Technology, to survey the earthquake ravaged areas of Pakistan and to come up with a plan for reconstruction of rural dwellings. ‘I was one of the technical experts to assist HFHI in planning how to rebuild long-term permanent shelters for the earthquake victims. Our team investigated two mountainous areas in Northern Pakistan which were hit hard by the earthquake-Bagh and Balakot, where 70% of the buildings were destroyed. In total, more than 3 million people have been made homeless by this earthquake. During our survey, the team assessed the damage conditions and tried to figure out how we could contribute our technical assistance as much as possible,’ said Dr. Pennung. Other members of the team, who carried out their survey from 1-5 November were Mr. Dan Bavington, Managing Director of ZOR Engineers (PVT) Ltd., Mr. N.M.S.I. Arambepola, Director of Urban Disaster Risk Management at the Asian Disaster Preparedness Center , and Mr. Samantha Rex, Project Advisor, HFHI. Based on the team’s investigation, HFHI is planning a 2-phase program – Phase 1 involves providing winter shelters urgently needed by the villagers in the target area before the arrival of winter, and Phase 2 is to set up and run a technical resource and training center near the target area for post-winter reconstruction of houses.
The team found that most low-rise reinforced concrete frame buildings in addition to the villagers’ traditional houses with walls made of stones and mud were totally destroyed in strongly shaken areas such as Balakot. ‘The villagers use mud and straw to build their roofs and make them thick for protection from rain. The walls that support the heavy roofs normally consist of layers of stones, one on top of the other, randomly laid with no binding material between them. If mortar is used, it consists of mud rather than cement. So, when the earthquake took place, a large lateral force was developed by the inertia of the massive roof, and it easily destroyed the fragile stone walls, leading to collapse of the houses and a lot of deaths and injuries,’ Dr. Pennung explained. Dr. Pennung has proposed an initial concept for rebuilding of houses; his design is for earthquake resistant octagonal houses. ‘I had to first think about what caused the damage and then to incorporate use of local building materials. I feel that the villagers do not want to change their way of life, so I only considered the original building materials and adjusted them as little as possible,’ he said.
Dr. Pennung’s concept allows the villagers to continue building their houses from stone, but all the voids between stones are to be filled with cement mortar (cement mixed with sand) to make the walls stronger. The stone walls have to be arranged in a configuration that offers good seismic resistance. For the same floor area, an octagonal-shaped house will be much stronger than a typical rectangular house. (See Pennung’s drawing and notes.) A shallow foundation strip may be used, but the strip must be made in a closed loop configuration. For the roof, he suggested that villagers can continue to build it from mud and straw, but to make it lighter and thinner and for protection from rain to coat the top with a layer of asphalt (such as FlintCoat). ‘The task of making these changes seems to be easy, but because we need to change the building methods, it will be necessary to hold a training with a model demonstration house at the site. And, we also need to know whether the villagers can accept this idea. There will be some more adjustments in the design to be made until it suits them. They can start rebuilding their shelters by this coming spring,’ Dr. Pennung added. ‘The focus of my teaching and research work has been on engineering structures such as reinforced concrete. So, this my first time that I have dealt with traditional structures and I had to look for easy methods for building shelters; this experience can be adapted and added to my teaching curriculum at AIT. I hope that in the long-term, AIT will continue to contribute technical assistance through this team and other technical teams. This is one of several solutions that can improve lives and serve the most people,’ concluded Dr. Pennung.
