SEAOC - SESOC Collaboration Updates

by: Libby Lindsay, SESOC Travel Scholarship Winner

The 2025 Structural Engineers Association of California (SEAOC) Convention was held in San Diego, California in September. We had a 10-strong New Zealand contingent attend the Convention, with five of us presenting. It was a rewarding experience to present internationally, and from the start the strong relationship and ongoing collaboration between SESOC and SEAOC were evident.

The Convention followed a format similar to the SESOC Conference, with a keynote speaker, awards, and plenty of networking opportunities. It also featured four parallel presentation tracks delivered in 45 minute slots. The closing session was a very American experience, it turned out to be an American-style game show, think The Chase, but for structural engineers with young members competing against SEAOC Fellows. A notable similarity between SEAOC and SESOC is their shared commitment to developing and providing opportunities for emerging structural engineers.

I really enjoyed the presentation by SEAOC Director Garrett Mills on the Practical Application of the SEAOC Fire-Exposed Foundation Guidelines. In January, Los Angeles experienced extremely destructive Southern California wildfires that burned for several days. Consequently, there was extensive structural damage, much of it irreparable. It was interesting to learn that the standard post-wildfire procedure is for the destroyed structure to be completely removed and disposed of, with the option for the foundations to remain. If the foundations are retained, prior approval is required before any reuse, and a structural engineer must evaluate their suitability. The talk focused on the ability to identify if concrete foundations and basements were able to be salvaged and reused. SEAOC developed investigation guidelines to evaluate existing foundations for reuse within one week of the wildfires starting. I found this pretty extraordinary, and it demonstrates the influence that SEAOC and structural engineers have within the community.

I am very grateful for this opportunity. This ongoing collaboration between SESOC and SEAOC is a valuable way to grow and gain insights into structural engineering across the Pacific. A big thanks to SESOC, SEAOC and Beca for making this happen.

by: Stuart Oliver S.E., President, Structural Engineering Society New Zealand (SESOC)

The New Zealand Government announced on 29^th September 2025 an intention to make significant changes to how the seismic risk of existing buildings is managed.  New Zealand’s current Earthquake-Prone Building (EPB) system was introduced in 2017 following the 2011 Christchurch earthquake. The current system is a national risk-based framework and includes all non-residential buildings and multi-storey residential buildings with three or more units. The seismic capacity of these buildings is assessed using the New Zealand Sesimic Assessment guidelines (which are broadly similar to ASCE 41), with seismic capacity expressed in terms of a percentage of that which would be required under the New Building Standard i.e. %NBS.  Buildings with a seismic capacity of less than 34% NBS are deemed to be Earthquake-Prone and building owners are typically given between 15 to 35 years to strengthen or demolish these buildings.

Proposed changes to the EPB system announced in September are intended to reduce the scope of the system, to focus mandatory mitigation requirements on building typologies with higher risk characteristics (e.g. heavy buildings of three or more storeys and unreinforced masonry (URM) buildings) in high and medium seismic hazard areas.  Specific structural features that would result in heavy buildings being classified as high risk have yet to be confirmed, but are expected to include buildings with features such as non-ductile concrete columns or non-ductile slab-column connections etc.

Seismic mitigation requirements for UMR buildings in small towns (i.e. defined as having a population less than 10,000) would be significantly reduced with one or two storey buildings no longer requiring any strengthening.  Whereas for URM buildings in small towns with three or more stories, the seismic mitigation would be limited to façade securing only.  Lower seismic hazard areas such as Auckland and Northland would be removed from the EPB system entirely. 

Reasons for the proposed changes include that the current system is capturing significantly more buildings than original intended.  In addition, too much emphasis has been placed on seismic assessments, in contrast to other countries with seismic regulations for existing buildings where there is more focus on the retrofit program itself i.e. the non-ductile concrete building ordinance in Los Angeles.  Furthermore, many owners of earthquake-prone buildings have been unable to access funding to undertake strengthening due to finance sector lending policies.

Recognising that this was a government policy announcement, we are expecting more information on the proposed changes to the EPB system in the coming months.  Parliamentary Select Committee hearings are planned for the first half of 2026.  SESOC will be participating in these hearings and will provide submissions on behalf of our members on the proposed changes.

by: Jessica Chen S.E.

I attended the SESOC 2025 Conference in Wellington, New Zealand, as the winner of this year's travel scholarship, funded by SEAOC member contributions through the SEAOC Foundation. The conference was held in the country’s capital city of Wellington and was my first conference experience outside of the United States.

Laura Whitehurst, project director at Holmes Wellington and a member of the SESOC-SEAOC Collaboration Committee, whom I knew when we both worked at Walter P. Moore in California, kindly gave me a tour of her project for the new Parliament buildings. The 2 new buildings and associated infrastructure are developed to house Members of Parliament and staff, ensuring a secure parliamentary precinct which reflects the country’s heritage and culture. Besides the project's significant cultural and political influence, the buildings employ a series of innovative structural strategies that are not commonly seen in the US. The buildings use lateral systems of timber braced frames and timber moment frames and are base-isolated with supplementary damping. It was impressive seeing such a unicorn of structural design as part of my conference experience. 

Among the conference program, I was fascinated to learn about the technical standards updates in New Zealand in one of the keynotes. Different from ASCE 7, New Zealand’s TS1170.5 is more focused on ductility and capacity design, especially after the 2011 Christchurch earthquake. ASCE 7, on the other hand, integrates a broader range of seismicity and relies on tabulated R-factors with less direct emphasis on ductility. There were also project showcases from Kiwi engineers that addressed unique challenges that projects in the US may not encounter, like the country’s highly liquefiable soil condition, and designing precast foundations for an energy project on a remote island in the Pacific Ocean.

I received a warm welcome from the entire SESOC community, including SESOC Executive Officer John Snook, SESOC President Stuart Oliver, SESOC Vice President Tessa Beetham, and other members of the SESOC Conference Committee. I also connected with Henry Rowden, the SESOC Emerging Structural Engineer (ESE) Committee chair, and Libby Lindsay, the SESOC ESE Traveling Scholarship Winner, who attended the SEAOC Conference in San Diego in September. Emerging Structural Engineer Committee is the New Zealand equivalent of Young Member Group. Having served as the NCSEA Young Member Support Committee chair myself, it was great to meet other young member leaders outside of the US. In the Emerging Structural Engineers sessions, I presented How to Engage Young Members at a Local and National Level Successfully, sharing experiences from Young Member Group leaders in the US. 

The conference location was across the street from the Museum of New Zealand Te Papa Tongarewa, one of the major museums in the country, showcasing New Zealand’s culture and history. I visited it in between the conference sessions. It was cool when I found out that there was a dedicated exhibition about earthquakes, and even a shake table for the children to build structures with sticks to understand the basic principles of seismic structural design. It’s great to see how the country pays attention to building an earthquake-resilient community on a societal level.