Monday, August 07, 2006

Building Autopsy

Banda Aceh, Aceh, Indonesia

Today we did some autopsy on already built homes by the other NGO we're evaluating for. Since many of the home have already been plastered, we had to hammer away to see the connections and brick work.


Anonymous said...

I do not know much about masonry but my lack of knowledge has not ever prevented me from weighing in on a topic. I do know that every time there is an earthquake in the States, the best footage they have is toppled, unreinforced masonry. So IMHO:

First thought: Ductility dude – a good thing. Brittle failure is sudden and catastrophic.

That wall is going to move out-of-plane in an earthquake. Maybe not much at first but as the tension side starts to crack and the compression side starts to crush, the deflections will get larger with each oscillation until the secondary moments increase to a point that the bricks fall and crush all of the young children of Bande Ache. Nice work Forrest.

Similarly, in-plane, the frame is going to deflect, cause rotations at the joints and move away from the masonry wall and leave it totally unsupported. Again to topple and crush the young children of Bande Ache.

Why the infill wall anyway? Seems to add a bunch of weight and maybe a little stiffness in smaller events? Why not wood siding and spend money on the reinforced concrete frame, detailing for ductility? I see rebar in the photos. Given the high seismicity of the region, seems you will never be able to design the structure “strong enough” to remain elastic so make it as light and ductile as you can.

Or just find your local FRP contractor and retrofit with a nice fiber reinforced overlay and call it a day.

You’re really doing it Forrest, good job. But as soon as you get back we have a bunch of equipment anchorages you need to work on.

And most importantly, how’s the surf?


Anonymous said...

We can't use wood, we have to infill with brick, it'll cost too much otherwise. I know, there are so many easlier ways to build this house. This is the way they build here, we have to work with what they have. If we tell them to build a different type of house (ie wood) they just won't build it and go back to the old bad habits.

I took a peek at the Indian Ocean coast, it's wild, I don't think you can handle the waves, Owen. it also has a real nice blue/teal color.