[BinasiDombrs]

Here is what I am talking about.

Earthquake Proof House - ARCHITECTURAL ENGINEERS DESIGN HOMES TO WITHSTAND EARTHQUAKES

[RicyReetred]

I have an earthquake field investigation report covering the China Sichuan Earthquake in 2008. Although most of the information covers commercial, industrial and public buildings there is a small section on residential buildings and a small appendix on retrofitting buildings. Some comments in the report include.

Most dangerous building are those with garages under the building, these are called weak first floor and many of these types of buildings pan caked.

Many buildings were built with reinforced piers, however, walls were not reinforced (unreinforced masonry) thus they collapsed and in some cases caused the entire building to collapse. Many school and hospital buildings were built in the 1990's with precast concrete slab/beam systems with unreinforced masonry walls. Most collapsed, although some survived believed to be mainly due to teh orientation of the building with respect to the shaking direction. It is believed that construction quality played a role as well.

Many buildings worldwide, US, Canada, South America, and Eastern Europe are built the same way as many of the buildings that collapsed in China. These building types tend to be in areas not recognised as highly seismic.

The document is a locked pdf (6.5MB) so I cannot paste here. If anyone is interested in a copy send me a pm and I will forward by email.

[Wheldcobchoto]

can you unlock the PDF and post it: PDFUnlock! - Unlock PDF files online for free.

or this one:

http://www.ensode.net/pdf-crack.jsf

[Svatudjw]

"Tsunami associated with the quake killed 1600-1800 people, for a total of about 2550 fatalities.
from wikipedia

Well I am sry, u seem to be right... I just have no clue where I got that info from. I am pretty sure I read it somewhere, but maybe it was gossip outside a colmado

[RicyReetred]

Thank you Adrian

The entire document is 48 pages so it certainly cannot be posted here. I am also a novice at posting pictures from my hard drive so pictures are not included. Below is the section (minus pictures) from the residential buildings.

Residential Buildings: Overview
Hundreds of thousands of houses collapsed as a result of the Sichuan Earthquake. Most of the collapses were in older, traditional unreinforced masonry (URM) construction or in modern buildings that had weak
first stories (soft-story buildings).Typical traditional houses are composed of URM walls and wood roof systems with clay tiles forwaterproofing. This type of system has very little lateral capacity. These roof tiles are lighter and thinner than the similar Japanese version, and are not interlocked. Therefore, seismic acceleration “popped” these tiles and saved the structure below by reducing the weight on the roof level. However, if acceleration is
high enough, walls will fail out-of-plane. The URM walls are composed of either red brick or mud brick, and without reinforcement, the walls will collapse in strong shaking. Some URM mid-rise structures performed adequately (did not collapse), unless there were seismic
configuration irregularities. Typical mid-rise apartment buildings are composed of URM walls and concrete floors. Often, concrete collector/chord elements are at the perimeter of each floor, and nonductile details are used. Each apartment is very small, and this configuration provided additional shear strength, which saved the building from collapse in many cases.

Residential Village North of Mianzhu
This small village of residential structures endured devastating damage. Over 80% of the buildings collapsed. The structures were built of brick walls and wood-frame roofs with lightweight black roofing tiles. These tiles are very light and actually helped reduce the seismic force to the building by falling off.
However, walls made of unreinforced brick have little stability against earthquake forces.

Apartment Building Complex
Several eight-story apartment buildings make up a complex in the middle of Hanwang township. These buildings are all made of unreinforced brick walls and concrete slabs. Many diagonal shear cracks occurred in the walls between windows, but the buildings did not collapse. These brick walls resisted the seismic force and protected the buildings from collapse. Each room is very small, which results in a lot of walls. The more walls that exist, the higher the seismic capacity of the structure is. Several older residential
buildings performed well enough to prevent collapse because of this design feature.

Residential Complex
In several adjacent buildings of the same construction, the first-floor (unreinforced brick) end walls failed and pancaked to the ground.
These structures dropped by as much as 10 feet and tilted, causing the buildings to split vertically near the middle. There were few walls to resist
seismic forces, and the structures had a lot of windows (which provide no seismic protection).

The following example is a retrofit example for a Unreinforced Masonary (URM) Walled Building. The scetch was 4 stories.

Retrofit Example (There are 4 goals and related solutions, cost increases with each)
Deficiencies (Note for all retrofit goals)
URM Lack of ductility and lateral capacity.

Retrofit Goal
Reduce lateral loading demand on URM walls.
Implementation
Add full-height ductile, reinforced concrete shear walls on the exterior of the building to carry the entire lateral load demand.

Retrofit Goal
Confine floor panels to work as a unit at each level.
Implementation
Check strength and ductility of existing concrete “ring”beams. Reinforce and confine them as needed. Add ring beams at each floor if they are not present.

Retrofit Goal
Enhance capacity of URM walls.

Implementation
Apply engineered cementitious concrete (ECC) to the exterior of the walls. ECC will add strength and ductility to the walls and allow them to resist seismic forces without collapse.

Retrofit Goal
Reduce seismic demand for immediate occupancy or critical facilities.
Implementation
Placing the structure atop of seismic isolator bearings to get a low-frequency and highly damped building that will protect nonductile components.

[bromgeksan]

A good engineer and architect should be able to design some quake resistant features into a home. Many buildings in places like SF and Tokyo are designed to move with the earth and not be totally stiff. Where's Chip when you need him to expound on this very topic.

I'm not a structural engineer, but I do know my house here in Santiago is built stronger than 90% of the homes in the US, what with the deep foundations, plentiful rebar and concrete. The rebar is the trick to, as it allows movement.

However, as some pointed out, if the ground starts to liquefy, you are more than likely in trouble regardless of construction type unless you building is built on "piers", structures that go into the ground relatively deeply. This is just a guess really because this isn't my area of expertise.

Also, I understand the PAP earthquake was shallow, which again means it's effects should be stronger. A very similar strength earthquake happened in 1995 in Japan, and there was major loss of life and infrastructure, even though they had in place strict construction codes and whatnot. In fact here is an excepted comment from the below link:

In the aftermath, both citizens and specialists lost faith in the technology of their early warning systems and earthquake construction techniques.

Great Hanshin earthquake - Wikipedia, the free encyclopedia

In other words, depending on the type of earthquake it may not matter how strong your house is. That being said it would seem to be prudent to build a one level house with a lightweight roof. Of course, then you have to worry about the hurricanes. Such is life.

[Erawise]

Here are some fotos from 2003 DR quake
More at Dominican Republic Earthquake Reports and Photos

[qd0vhq4f]

One thing to remember is that even if your house has sufficient rebar, and was properly built, what you should be hoping for is that your building doesn't collapse.

The whole idea of building correctly is for the structure NOT to collapse on top of you, but it'll be tough to get away from the walls cracking up.

[Wheldcobchoto]

A very similar strength earthquake happened in 1995 in Japan, and there was major loss of life and infrastructure, even though they had in place strict construction codes and whatnot. In fact here is an excepted comment from the below link:

In the aftermath, both citizens and specialists lost faith in the technology of their early warning systems and earthquake construction techniques.

Great Hanshin earthquake - Wikipedia, the free encyclopedia

According to your link, ~6000 people died in Japan only.