By David Ojala, Chair, SEAOC Existing Buildings Committee
Fun fact: Every building is, or will soon be, an existing building. This makes the breadth and reach of the SEAOC Existing Building Committee’s (EBC) influence very significant, when you get to thinking about it. This article will provide an overview of what the SEAOC EBC has been up to lately, and the schemes we’ve been masterminding for the year to come.
EBC members are practicing structural engineers who deftly brandish non-linear analysis and develop innovative technical solutions with the best of them, but much of our committee’s work is inherently “softer” and less technical than you might expect. While code changes allow us to apply new research or lessons learned from earthquakes to make new buildings safe, what are we to do about existing buildings that are now known or suspected to perform poorly? Are these “deficiencies” so severe that they warrant retrofitting? Should these retrofits be mandatory or just voluntary? How quickly should these conditions be remediated? How much will each fix cost, and who will pay? Should these buildings be made to meet new code performance levels, or is a reduced level of performance acceptable? How do we communicate these issues to the public, to building officials, to engineers, and to lawmakers? Will this author write an eighth rhetorical question in a row, just for the heck of it? Yes, yes he will. Managing the nation’s ever-expanding building stock is no small feat, and our committee’s work involves as much legislation as calculation, working alongside our local jurisdictions to help develop ordinances for retrofitting hazardous buildings as well as tools and guidelines for practitioners to meet the intent of those retrofits as quickly and efficiently as possible.
With what is arguably California’s greatest seismic hazard, unreinforced masonry buildings, largely mitigated or reduced by statewide mandatory retrofit programs, attention has turned to two other building types that house large numbers of California residents: soft-story/weak-story/open-front (SWOF) wood-framed buildings, and non-ductile concrete (NDC) buildings. SWOF ordinances in San Francisco and Berkeley (developed with the assistance of SEAONC members) are already in effect, but several Southern California jurisdictions have recently been fast-tracking similar legislation, and SEAOSC is working to make sure that the engineering requirements behind these are sound. The SEAOC EBC has been an excellent forum for sharing new developments and advice to make sure that unforeseen challenges confronting SEAONC members can be avoided by the other MOs. However, Southern California jurisdictions are upping the ante by moving forward with mandatory NDC ordinances, something that other jurisdictions, statewide, have on their radar. By working together to contribute as much Association input into these seminal programs as possible, we hope to make it easier for other jurisdictions to follow suit, and for our membership to effectively and efficiently reduce the hazard posed by these building types and improve California’s seismic resilience.
In a similar vein, SEAOSD has been spearheading an effort to develop a hazard-reduction report card to grade jurisdictions on their efforts to mitigate key seismic hazards, such as URM, tilt-up, SWOF, and NDC buildings. With several jurisdictions enacting robust retrofit programs for all of these hazard types that can set examples for programs statewide, our goal is to encourage jurisdictions to start taking steps to protect their residents, as well as to provide guidance regarding key components of successful programs. The only thing more powerful than the SEAOC EBC is peer pressure, and we’re harnessing that too. Look out.
Although the EBC has been doing enough policy work lately to make a Capitol Hill wonk giddy, we have not let our technical tasks fall by the wayside. Helping to provide tools and guidance for engineers who are tasked with actually satisfying the requirements of these retrofits is an ongoing mission. Educating engineers on the benefits, limitations, and proper application of ASCE 41 is a priority, and our committee’s involvement in developing and reviewing example problems for the ATC-124 project is a big part of that. Maintaining Existing Building Code commentary, developing new commentary for new ordinances, and providing written examples for meeting retrofits are also hot topics at the state and local EBC levels. Finally, the EBC hopes to provide some clear guidance to engineers on a common challenge: installing steel moment-resisting frames in wood-framed buildings. A white paper is in the works, and we plan to have an update for you in Maui in October, if you can be bothered to put down your Mai Tai for just a few minutes, please.
I could keep going about these topics and more, but it’s time to put my proverbial pencil down. If anything I’ve written here struck a chord with you and you want to get involved, ask a question, or express serious doubt about our qualifications to lead this committee, shoot an email to your local EBC chairs: Wayne Brown (SEAOSD), Daniel Zepeda (SEAOSC), Darron Huntingdale (SEAOCC), and David Ojala (SEAONC).