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On site: Which buildings are safe?

Johann Zimmermann
January 24, 2010

Structural engineer Johann Zimmermann writes about his first days of evaluating structures in Haiti. Zimmermann is from Harrisonburg, Va., and attends Community Mennonite Church.

This is by far the worst earthquake I've ever seen. Most of the city is not flattened, like the news says it is. There are many remaining houses which are still livable, but in between and in certain areas, the damage is extensive. Most houses are two- and three- stories high. Everything is built with concrete and concrete block construction. Roofs are also all made out of concrete. There are many houses where the first floor is totally crushed under the weight of the upper floors. Half of the city is very hilly. On some slopes all of the houses have avalanched down.
We hit the ground running. We first thoroughly checked out the MCC office building, which also serves for housing for about eight of us at the moment. It is safe, but needs some repair. We spend the rest of the first day checking out a medical clinic/classroom building. The staff has not entered the three-story reinforced concrete building since the earthquake. People are just scared to enter buildings for fear of them falling down.
Our work is very detailed. We look for all the cracks and try to assess the importance of them to the structural integrity of the building. Many cracks are just cosmetic. Others are in non-bearing walls and not important to the building collapsing. These walls may be dangerous though because they can detach and fall over. One needs to look at the building from far, from near and into all the details and then put it all together to come up with a good judgment call.
We use the FEMA (Federal Emergency Management Agency) guidelines and marking system to classify the damage and come up with how much remaining strength the building has: if damage is only cosmetic, if it is safe for occupancy, if some critical repairs are needed before occupancy, or if it should be torn down. In the case of the clinic, we showed them two columns on the first floor that needed strengthening before they could move back in.
This morning we went to a church (Assemblée de la Grace, a Mennonite congregation just outside of Port-au-Prince) with some MCCers. It was held outside under a big mango tree (not in season) and sheets strung over wires. Beautiful singing. One really felt they were there to strengthen each other after all they have gone through. My problems felt pretty small compared to the challenges they are experiencing.
The church was too damaged for them to hold a service there. They have already decided to tear it down since they were already working on the construction of a new church adjacent to it. We went over the construction and showed them changes they should make to make it more earthquake resistant. Next we looked at a large concrete water tower, set on 20-foot-high concrete columns which had cracks. We determined that the columns could be repaired and gave them instructions how to do it. We spend the rest of the afternoon going through six houses in the adjacent neighborhood. Everyone wants their house checked out. Everyone is scared of entering them, even if they are still in good shape. They want the assurance of someone they think knows something about it, and advice on what to do to repair them. It’s good to work together in a team, so that with all the uncertainty and probability involved with earthquake damage prediction, we don't feel alone in making a decision which could well mean life or death for someone.
So, there is no lack of work ahead of us. We immediately got a request to examine the main hospital. We turned that one down because we think that larger organizations like the military, United Nations or the Red Cross will eventually fly in engineers to check large institutional buildings. We want to concentrate on smaller schools, clinics and public meeting places from smaller organizations. At each such visit we will request that the agency have us meet with a builder who will actually do the work so that we can immediately explain it to them. That builder also can get some knowledge on structural assessment so he can assess damage to private houses so that we don't get bogged down with that.
We are being taken well care of: water, food, water, good company and a great place to put our mattresses on the roof for sleeping under the stars. A light blanket is all that's needed.