Day 2 Report on Chile Earthquake by Degenkolb Team 2
Day 2 Report on Chile Earthquake 2010 by Degenkolb Team 2
We have been in Chile now for almost two days, in that time we have felt at least 5 earthquakes. Since the magnitude 8.8 there has been over 200 M5.0 or higher and at least 20 over M6.0. So the people of this region have been constantly reminded of the moving plates below them. Despite the difficult time, we have met many very friendly locals willing to allow us access to sites and to share some of their story. Our plan for the day was to look at more buildings in Concepcion and then look as some of the industrial areas near Concepcion.
The first site we visited in day 2 was very close to our hotel. It was a typical big box warehouse with tilt up wall. There was little to no out of plane anchorage and tall narrow walls, so the damage was not surprising. The roof girders appeared to be supported by the walls, so once they lost those panels a section of the roof collapsed. So far this is the only tilt-up construction we have seen, so it doesn’t seem to be normal for the region. The walls were approximately 7 inches thick and the taller panels were around 40 feet tall with a large sign cantilevered. The store was similar to the US’s Home Depots or Lowes. We usually don’t consider these stores to be essential after an earthquake (like a hospital or firehouse), but many locals are trying to rebuild their homes and businesses and not being able to go to a store like this can impact the recovery efforts.
The second site we visited was a set of condos. There were 4 sets of tower’s; each tower was about 14 stories. Only one of the four really seemed to sustain a lot of damaged, but all were still evacuated and some units were even abandoned by the owners. These were midrise concrete buildings similar to some of the ones were observed yesterday. All were only a few years old, so most likely built to the current codes. From our sidewalk perspective it appears structurally that these building performed how we would expect a code building to behave in a large earthquake. Most of the damage occurred where unique window bays tried to couple the shearwalls together in the first tower that we observed. We were able to walk through the second tower and see some of the damage inside thanks to one of the tenets. From the outside this unit appeared to have little to no damage with mostly architectural damage (stucco and glass). We walked the parking garage under the building and only minor damage.There was some damage at the seismic joint between the two towers below grade where a detail tied across the joint. We would usually not expect much movement at a join below grade, so this tells you how much this area was shaking. Then we started hearings the tenets story (thanks to Daniel) and we started to discuss if the codes’ intend is enough. After the earthquake many of the tenets were trapped in their units and had to bust through their jammed doors. The area lost all of their utilities, so all of the tenets had to exit through the stairwells. As this occurred in the middle of the night and the power was lost, people were blindly trying to navigate crowded stairwell. Now many owners have abandoned the units as there are still no utilities and many are afraid to return. In one of the units we visited, people literally took everything including the kitchen sink. We have heard of earthquake insurance being fairly common, but we were told some policies have fine print that voids the insurance if the earthquake is larger than a M7.5. So to most of the owners, they are willing to take the loss and move on.
Touching back to the resilience issue, in this once site alone there were around 800 units now abandoned. All of these people are now leaving the area or staying in temporary housing. How does this affect the community and economy around them? Since the earthquake, we were told rent has doubled since there is a lack of housing. There was a similar 16 story tower across the street in a differently development that appeared to have no damage. Despite this, we were told around 90% of the tenets have evacuated because of fear. From the buildings we observed yesterday including the collapsed apartment building, there appears to be a focus of the damage in mid-rise concrete buildings. So we could understand why many of the local no longer want to live in such buildings.
The third site we visited was closer to downtown Concepcion to see a building listed on the cities website (www.concepcion.cl). The third site was a quick stop to see 1535 Los Carrera, which was a 17 story concrete building with brick façade. The main issue appeared to be pounding from the parking garage and damage at discontinues. On the one site of the building one of the piers was completely blown out with the larger diameter bars with some fractured from tension and the rest buckled.
The fourth site was another mid-rise concrete building located at 1165 Freire. We first walked around the community and saw many unreinforced masonry buildings heavily damaged. It was hard to determine how old these buildings were. They did appear to be at least older then 1960, so it surprised us that they would have survived the M9.5 event. The focus of this site was to see yet another mid-rise concrete building. This building from far away seemed undamaged. It wasn’t until we got up close and saw sections of the wall heavily damaged. The entire block was closed off by police, in concern that the building could collapse from an aftershock. At this point there seems to be a theme, modern mid-rise concrete building with some irregularities.
The rest of the day we spent observing some of the industrial areas. (pictured below) We observed 3 different plants. Most of the areas that we observed did well with little damage. We are planning to spend one of the next day’s getting in a few of the other plants in the area. Seeing how these non-building structures performed was an interest to us as they serve as a lifeline to the community during the recovery. Although most of the ones we observed seemed to have minor damage, the plants are expected to still being limited to nonfunctional for a considerable amount of time to repair those minor damages.
It was a very busy day and too many stories to share in this blog. Overall, the experience has been amazing and Chilean people have been very gracious to our interests.
