The second full day reconnaissance in Tainan began with a brief meeting in the Department of Civil Engineering at National Cheng-Kung University. This day, another reconnaissance team from US joined the meeting. We went to the region close to a river where soil liquefactions were observed, especially the low-rise residential buildings affected by soil liquefactions. One building we visited had settled more than 10 inches during the earthquake. However, the building structure itself is intact and doors are able to open. We also talked to peoples who were inside the settled building during the earthquake. They said the building began to settle after they heard a big sound. Then soils and water came out from the cracks on the floor slab. The sand boils lasted about 4 to 5 minutes after strong shaking.
In the late morning, we visited a private high school in Tainan with retrofitted and non-retrofitted school buildings. The structural engineer who designed the retrofitted buildings gave us a presentation on the retrofit schemes he used in these projects.
After lunch we headed to one collapsed traditional market building with retail stores in the first story and residential units above. A market building built in the same time period next to the collapsed building did not collapse and was yellow tagged, where we found the building was partially retrofitted by adding additional gravity columns after the 1999 Chi-Chi earthquake.
We revisited the collapsed 10-story hotel and this time we examined the building closer. The bottom four stories were crushed as shown in the picture.
On the way to our last site, we visited another retrofitted school building and the building looked great.
The last site we visited is a district office building, very similar to what we visited before. However, this building is retrofitted with four RC shear walls and no severe damage was reported except the stainless steel water tank toppled on the roof.
The second full day of reconnaissance activities ended with a dinner in NCKU with other teams.