After more than four incredibly successful years in Indonesia – first in Aceh, and then in Western Sumatra, where it still has operations – Build Change opened an office in China in August 2008, to provide technical assistance to homeowners rebuilding after the deadly Sichuan earthquake in May 2008.
Since the topographical landscapes in the tropical islands of Indonesia and the bamboo-forested, mountain-encircled basin of Sichuan are radically different, I assumed that there’d be corresponding differences in the earthquake-resistant design features of the houses built in the two areas. Recently, I sat down with Build Change founder and CEO, Dr. Elizabeth Hausler, who explained why I was wrong:
MA: What are some of the differences between earthquake-resistant houses in Indonesia and China?
EH: Actually, there are more similarities than differences. Building an earthquake-resistant house starts with a homeowner who’s empowered to manage the rebuilding process. One “lesson learned” from donor-driven rebuilding efforts is that homeowners don’t trust the safety of rebuilt houses if they’ve been kept out of the rebuilding process. So, at Build Change, we start with the homeowners, and homeowners in Indonesia and China have a lot of characteristics in common.
MA: What are some of those similarities?
EH: Three main examples: people have limited funds, they don’t necessarily prioritize those funds well, and they don’t understand good construction. Both the Chinese and Indonesian government gave homeowners some money to rebuild, but it’s still not enough. So Build Change has to come up with designs that are affordable, as well as being earthquake-resistant. Also, people often spend too much on their foundation, and they’re out of funds by the time they reach the top of the house. But connecting the ring beam, at the top of the house, with the tie columns is more important for earthquake-resistance than a super-strong foundation. So Build Change has developed cost-estimates for its designs, which enable homeowners to select a layout that’s suitable to their space needs and their budget. And, of course, few people know about good construction if they haven’t done it themselves. So Build Change provides trainings for homeowners, to educate them about proper construction techniques.
MA: Other than the homeowners, what similarities (or differences) are you finding between Indonesia and China?
EH: Well, contractors are the same around the planet. Their motivation is to make money, and they’re likely to skimp on concrete or not use enough steel. In both Indonesia and China, we’ve found that contractors need supervision, and at Build Change we believe that the best person to do that supervision is the money holder – namely, the homeowner. So our approach is to empower the homeowner.
MA: What about the houses themselves? Are the earthquake-resistant design features for the houses in Indonesia and China different?
EH: Again, the similarities are greater than the differences. In both Indonesia and China, people like to build confined masonry houses. At Build Change, we accept whatever building system people want, and we figure out how to make it earthquake-resistant. For confined masonry houses, wherever they’re located, the earthquake resistant features are the same. Confined masonry houses have tie columns made of steel bars and concrete. The steel reinforces the concrete and connects the walls to the columns, as well as connecting the walls to each other through the columns. The tie columns also connect to the plinth beam at the foundation and to the ring beam at the top of the house. When all the structures are interlocked in this way, the house performs well in earthquakes. Without that interlocking, during an earthquake the top part of a house tends to move in advance of the lower part, and that flexibility is what leads to the house collapsing. Interlocking the walls and the beams via the tie columns makes the house rigid, so the whole house moves as a unified component in an earthquake, and it won’t collapse.
MA: What about the way the houses look? Can you use the same building system in Indonesia and China and still have houses that are aesthetically appealing to the locals?EH: Absolutely. At Build Change, we’re committed to building houses that are culturally appropriate to the area. So, for example, in Indonesia, the houses have very thin walls – 11 centimeters – as contrasted with 240 centimeters in China. People in Indonesia also like to use different roofing material, timber or corrugated iron sheeting. Those materials aren’t available in China, where people had been using pre-cast concrete planks, which performed very badly in the earthquake. Another example: in Indonesia, people like a vent over their windows. At Build Change, we listen when people say they want their house to have a particular feature, and then we design around it, so that the end result will be culturally appropriate and safe. Except for the pre-cast concrete plank – we’ve been telling people in China, there’s no way to make that safe!