2008 Issue

www.utahengineerscouncil.org 42 Engineering For the Public Good A NOTHER YEAR HAS PASSED AND THE STRUCTURAL ENGINEERS ASSOCIA- TION OF UTAH (SEAU) CONTINUES TO GROW IN MEMBERSHIP AS WELL AS promote safe engineering practices amongst its membership. Each year our committees contribute new ideas and methods to help improve the practice of structural engineering for the public good. Our seismic committee is assisting in publishing a public-use handbook describ- ing the threat posed by earthquakes along the Wasatch Front. Putting Down Roots in Earthquake Country (ROOTS) has been published in other seismically active regions and is now being modified and updated for our region. The Wasatch Front ROOTS hand- book, slated for publication in spring of 2008, explains how the general public can prepare for, survive, and recover from a significant seismic event. Another hot-button topic is environmen- tal sustainability. With raised environmental awareness, Utah structural engineers have actively pursued design methods aimed at reducing our carbon footprint and provid- ing green building design. Multiple rating systems help structural engineers determine the effectiveness of their green design. The most commonly used rating systems in com- mercial structures for green and sustainable design are the Leadership in Energy and Environmental Design (LEED) and Green Globes Environmental Assessment and Rat- ing System (Green Globes). While the LEED rating system is more commonly used across the Wasatch Front, Green Globes is growing in popularity. Each rating system takes into consideration such aspects as: life cycle of the materials used in construction; renewability of these materials; locality of the materials; the materials’ overall carbon footprint, and many other aspects of Green construction. These guides can help structural engineers to provide good green design by calling for use of recycled and renewable material in construction. Structural lumber not only comes from a renewable resource, but is now mostly har- vested from dedicated tree farms. Not much, if any, is wasted after the harvesting process. What doesn’t get cut into dimensional and laminated lumber is used to produce com- posite lumber with even better structural characteristics as well as many other consumer products. Another advantage in using struc- tural lumber is that the carbon, in the form of carbon dioxide, is consumed during the tree’s growth. This helps offset the carbon waste produced at the lumber mills and during the transportation of the product. Structural steel is also a green product. Almost all of the structural steel produced in the United States is fabricated from recycled steel. It is more expensive to mine and process raw iron ore than it is to recycle old steel. This is beneficial since, recycling and reclamation not only saves money and energy but also reduces waste products. The steel used today is much stronger than the steel produced fifty years ago. This allows the structural engineers to reduce the amount of steel in their design. The steel industry continues to update its methods of processing steel by making their furnaces more efficient, thus also reducing its carbon dioxide emissions. The production of concrete can use a material that may otherwise go to waste. Fly ash is typically added to the concrete mix design as a cementatious material. Fly ash is the fine mineral residue resulting from the combustion of coal, mostly a byproduct of electric generating plants that use coal fur- naces. Fly ash can be used in place of other, less green products such as Portland cement. The other advantage of concrete is that it uses mostly locally obtainable materials as components. In most cases there is no need to transport the water, sand and rock used in concrete over long distances. Green rating systems are not codified, so a material may be listed as beneficial in one system and not in another. However, using materials with overall green benefits help produce a structural design with a reduced impact on our environment. Utah structural engineers are dedicated to the public good through the inherent nature of our work. Strong, safe design combined with green design continues our legacy of providing long-lasting benefits for the public at large.