ASCE 41-06: Seismic Rehabilitation of Existing Buildings
A New Tool for Achieving Seismic Safety
by Chris D. Poland, S.E., F. SEAOC
September 2008–Earthquakes wreak havoc on our lives, our businesses and our communities. For the last 140 plus years, scientists and engineers have been working to understand where they can occur and how to best mitigate their effects. What started as a concern centered along the West Coast has become known as a real threat that affects the vast majority of states in the United States. Thanks to the work of the United States Geological Survey, we now have a science-based understanding of earthquake hazards nationwide, which has become the source for national earthquake hazard maps.
For over 50 years, engineers have focused on protecting lives and the vitality of our communities by writing building codes and seismic provisions. Engineers are identifying and rehabilitating “dangerous” buildings nationwide, and the need for conversations about community resilience are refining how we approach design. Unfortunately this progress achieved full stride just 20 years ago and has left us with an inventory of buildings nationwide where more than 80 percent are unable to meet the recognized seismic standards where they are located. The seismic rehabilitation of the existing building stock is a key element in the process of achieving seismic safety and turning our cities into resilient communities.
Unsurprisingly, when owners understand and accept the risk of an earthquake, they want it brought under control and mitigated to an appropriate level. Often it takes a personal, life-changing earthquake experience to bring home the reality of an earthquake’s consequences. For those owners who lack such personal experiences, the consequences of earthquakes must be described in intuitive terms in order to appreciate the importance of seismic mitigation. Another barrier to mitigation is cost; many interested owners have done nothing because they think that the investment required to bring older buildings “up to code” is ridiculously high. Finally, we structural engineers are too often reluctant to speak up and declare what is going to happen because we sense that somehow we will be held responsible when it does. Our personal liability fears often stop us from speaking up, even though our silence leaves the impression that there is not a problem.
To read the complete story published in Structure Magazine, click here http://www.structuremag.org/article.aspx?articleID=752
