Martin Dawson, owner of Dawson Foundation Repair, has recently offered to consult with the government and people of New Zealand regarding their earthquake damaged homes and commercial buildings. On February 22, 2011 the Christchruch area of New Zealand was struck by a devastating earthquake that destroyed and damaged thousands of homes and buildings and killed 185 people.
Almost three years after the massive earthquake the country has issued a new technical report on the foundations supporting homes and commercial buildings. The country’s Housing Minister, Dr. Nick Smith, said there are tens of thousands of homes with damaged foundations and the question has been “What to do?” He stated that the answers will be both difficult and expensive for the thousands of homeowners. The Housing Minister, who has a PhD in Geotechnical Engineering, also said that the issue is difficult for the insurers, engineers, and contractors as well. In addition, he said “The scale of the damage to housing foundations from liquefaction in Christchurch is unprecedented internationally.”
Liquefaction is a phenomenon which can occur during an earthquake to saturated or partially saturated soil. The movement or “shaking” caused by the earthquake will result in this soil losing it strength or stiffness and behaving like a liquid – at least temporarily. This can result in soil movement of various types – lateral and vertical. Liquefaction is more likely to occur in soils that are granular, such as sandy or silty soils.
Mr. Dawson has worked with the clay and silty soils of Texas for more than 30 years and he has seen similar problems in soil movement. “The problem in Texas is that the clay soils act like a sponge – when there is water available the soil will absorb the water and expand in volume and when the weather is hot and dry the soil will lose water and shrink in volume. The net result is that the soil is moving up and down and sideways, which puts tremendous stresses on concrete slab foundations. So the challenge is how to support a concrete slab foundation from future soil movement. We have seen 6 and 7 inch vertical soil movement in Texas but I don’t know exactly what they experienced in New Zealand.”
Perhaps the most unique fact about Mr. Dawson and his company is that he is loyal to a single foundation repair method called the Bell Bottom Pier method. When asked why this method might help homes on the other side of the planet he stated, “The Bell Bottom Pier is the best method to resist soil movement in Texas and I think it could be beneficial to New Zealand. No other commonly used method in Texas offers the strength, proven track record, and permanency of the Bell Bottom Piers. You can use cheaper methods but if you have soil movement there is a high probability they will fail to support the foundation and home over the long-term.” He continued by saying “You want to save the homes if possible so the foundation repair method that is selected should have an excellent history of success. I really feel bad for those people who lost their entire home. It must be devastating.”
Martin Dawson can be contacted through his website, DawsonFoundationRepair.com.