Monday, September 1, 2014

Napa EarthQuake Structural

Here's some pictures of the buildings I visited on August 31 2014. 7 days after the 6.0 Earthquake in Napa California. The structural damage I viewed suggested that it was a unreinforced masonry - brick tension tie failure, or lack of tension ties. Unreinforced masonry was banned in California in 1930, due to its vulnerability during earthquakes. Downtown Napa is open for business and the earthquake damage is a new tourist attraction. Walking around Napa, it looks like there's only about 1% of the buildings in Napa there were damaged by the earthquake. The Historic Napa Mill and RiverFront Inn looked like it had no exterior damage to the 3 story building.

Extreme Danger
Stay Back 100 Feet

This National Disaster Team didn't read the Extreme Danger sign. 
So, what is in those two trucks? Or are they there just for advertising?

I was in this building 6 years ago. I remember seeing the tension ties running thru the building. The main damage to this building was the front of the building where there are no tension ties.

Here's the famous dangling roof that was part of a recent retrofit. Apparently the tubular steel with rods 16" O.C. should had the rods protrude thru the exterior wall with plate washers. It probably needed an steel uplift post at the corner as well.

This church with the exterior parapet wall detached from the roof framing needed some type of wall to roof connection. This is a lot of weight leaning towards the street. It needs some raker bracing.

Wood frame structure

Wood is one of the best materials for earthquake-resistant construction since it is lightweight and more flexible than masonry.  This Victorian house and 100's more are right across the street from the church with the leaning rake wall. These Victorian homes didn't appear to have any exterior wall framing damage from the earthquake. I had forgotten how many Victorian houses are in downtown Napa. 

The GoodMan Library, historical society, needed bigger tension ties to hold the exterior brick-stone walls together in an earthquake.Again it should of had tension ties with plate washers on the outside of the building.

This church had stain glass windows blown out in the earthquake. However, the exterior framing looked pretty good.

I stayed in the Church Hill Manor bed & breakfast Inn 6 years ago and it didn't appear to have any damage from the earthquake.

The United States Post Office in Napa definitely needs some repair. Again it could've used some tension ties with plate washers to prevent this crack in the exterior wall of the building. Right across the street from the post office is a newer building with all glass exterior walls and some brick veneer. This building looked completely unaffected by the earthquake.

The castle, Napa State Hospital -- Asylum for the Insane, was torn down after world war II. However, it represents the love affair with building with bricks in the 19th century. I researched to see why it was torn down, but never found an answer. This brick building was doomed from the time the first brick was laid.

Link to all of my pictures of the Napa Earthquake.

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