Building on Solid GroundPeople are flocking to the sunny southwest in droves. But sunny, arid climates come with dry soils, which pose problems for the construction industry. Sandra Houston is working on a solution.solidground.html<A HREF="../2006/engineering_4.html">Engineering and Technology</A>: <A HREF="../2006/engineering_4.html#civil">Civil Engineering</A></P>


<P CLASS="lefttext"><STRONG>Related ASU Web Sites</STRONG><BR>
<A HREF="http://www.fulton.asu.edu/~civil/">Department of Civil and Environmental Engineering</A></P>
<P CLASS="lefttext"><STRONG>Publication Date: Fall 2004</STRONG></P>
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Life in the sunny, arid Southwest is a siren call to thousands of people depressed by gloomy Midwestern skies and wet, freezing Eastern winters. The result is rapid population growth and a booming demand for new home construction in Arizona and other western states. But sunny, arid climates come with dry soils. Building on those soils poses a unique problem for the construction industry.
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Sandra Houston is working on a solution. She and colleague William Houston are professors of civil and environmental engineering at Arizona State University. They study the mechanics of soil low in moisture content, the soil most often found in arid or semi-arid climate regions.
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&#147;Arizona&#146;s climate goes from very dry to very wet because urbanization and landscape irrigation results in the addition of lots of water,&#148; Sandra Houston explains. &#147;The problem is the change in moisture and the amount of that change in the soil.&#148;
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In Arizona, homes are often built atop concrete slabs. Soil beneath those slabs can move due to the change in soil moisture content. Such movement can lead to structural cracks and other major headaches for builders and homeowners.
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The research team also includes Delwyn Fredlund, a leading expert on the study of unsaturated soils, and professor emeritus at the University of Saskatchewan, as well as ASU faculty research associate Claudia Zapata.
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&#147;Clay soil is like a sponge. It expands when it takes in water,&#148; Fredlund says. &#147;When the sun comes out and the water evaporates, the soil contracts.&#148;
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The group is developing computer models to evaluate different types of soil systems for arid climatic conditions. They also want to create methods for educating builders, homeowners, and engineers on the &#147;do&#148;s and &#147;don&#146;t&#148;s of building on unsaturated soils.
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&#147;We have the equipment. The theory is in place. We have great tools,&#148; Zapata adds. &#147;Now we need to combine everything to solve these important problems.&#148;Research on saturated soils is supported by the National Science Foundation and the Homebuilder&#146;s Association of Central Arizona. For more information, contact Sandra Houston, Ph.D. Send e-mail to <A HREF="mailto:sandra.houston@asu.edu">sandra.houston@asu.edu</A><A HREF="../2006/engineering_4.html">Engineering and Technology</A>:&nbsp;<A HREF="../2006/engineering_4.html#civil">Civil Engineering</A>