The past 12 months have flown by! It is hard for me to believe that this is the last message that I will send to you as the SEAOSC President. It truly has been a privilege to serve this Association. I am proud of all that we have accomplished together even during a year like no other. To our Members, Sponsors, and partners, thank you for your support and all the amazing work that truly has a made a difference.

A few weeks ago, we celebrated our Safer Cities Awards and the EiSE Awards. Look for us on LinkedIn and join us in continuing to celebrate the awardees. On June 24^th, the celebration continues when we will celebrate individuals that have made a difference for our Association and our industry including announcing our Engineer of the Year and our Nominee to the SEAOC Fellows. The event is free and includes time to reconnect with your fellow SEAOSC Members (https://seaosc.org/event-3920037). Additional details about the June 24^th event have been included at the end of this message.

Craig has practiced structural engineering in the Southern California area for over 24 years. After merging the practice he founded in Los Angeles over a decade ago, he now leads IMEG’s structural team in Los Angeles. He is a registered professional Civil and Structural Engineer in California as well as several other states. Craig has a wide range of experience from hundreds of projects in residential, commercial, and industrial industries which also include expertise working with California DSA and OSHPD regulated projects. Craig has been a member of the Structural Engineers Association of Southern California his entire career and previously served on the Board of Directors from 2010-12. He was also a member of the steering committee of SEAOSC’s inaugural Building at Risk Summit as well as a member of the Existing Building Committee and multiple SEAOC Convention committees. Craig is currently the acting Golf Chair for SEAOSC and has served in that role since 2019.

Craig was born and raised in Southern California and currently lives in the South Bay with his wife and three sons (twins age 5 and older son age 10).

Dan graduated with an Architectural Engineering degree from California Polytechnic State University, San Luis Obispo in 2006 and has been working at MHP Structural Engineers ever since. Dan’s structural expertise and design experience includes the use of many different construction materials including wood, steel, masonry, cast-in-place concrete, and pre-stressed concrete. Dan has managed education, multi-family housing, and retail projects, including many Target stores. He has extensive experience with both new buildings and seismic evaluation/strengthening/renovation projects, including performance-based seismic evaluations and designs. Dan has also completed numerous Probable Maximum Loss (PML) seismic risk assessments. He is proficient in the three-dimensional computer modeling and analysis of complex and multi-story buildings, with expertise using intricate structural solutions such as carbon fiber reinforced polymer, buckling-restrained braced frames and fluid viscous dampers. He has also completed sustainable projects including net-zero energy and LEED-certified buildings.

As Project Manager, Dan serves as the day-to-day project contact with responsibility for overseeing MHP staff and communicating with project teams from predesign through construction completion. Dan collaborates with the team in the selection of structural systems to meet the project’s budgetary, design, and programming needs.

Dan has been involved with SEAOSC for over 15 years and is a past chairperson and current member of the Education Committee.

Maria Mohammed joined Structural Focus in 2013 after graduating from the University of Southern California with a B.S. in Civil Engineering in 2012 and an M.S. in Structural Engineering in 2013. Maria is a licensed Structural Engineer in California and has extensive experience working on the retrofit and renovation of historic structures and existing buildings, as well as the design of new buildings. She has worked on significant projects at Structural Focus, including Google LA HQ, the John Anson Ford Amphitheatre, CBRE Masonic Temple, and several projects on the Paramount Studios lot, among others. Maria has been involved with the Structural Engineers Association of Southern California for many years. She was the co-chair of the Young Members Committee from 2016-2018 and has been the chair of the Communications Committee since 2018.

Dr. Henry V. Burton is an Assistant Professor and the Englekirk Presidential Endowed Chair in Structural Engineering in the Department of Civil and Environmental Engineering at the University of California, Los Angeles (UCLA). His research aims to understand and model the relationship between the performance of infrastructure systems within the built environment, and the ability of communities to minimize the extent of socioeconomic disruption following extreme events such as major earthquakes. He teaches graduate courses on Advanced Structural Analysis and Structural Reliability and an undergraduate course on Structural Testing and Analysis. Dr. Burton is a registered structural engineer in the state of California. Prior to obtaining his Ph.D. in Civil and Environmental Engineering at Stanford University, he spent six years in practice at Degenkolb Engineers, where he worked on numerous projects involving the design of new buildings and seismic evaluation and retrofit of existing buildings. He is a recipient of the National Science Foundation Next Generation of Disaster Researchers Fellowship (2014) and the National Science Foundation CAREER Award (2016).

Ken D. O’Dell joined MHP, Inc. in 1989 after graduating from Cal Poly, San Luis Obispo with a Bachelor of Science Degree in Architectural Engineering. At MHP, as one of five principals, he manages design and seismic renovation projects and leads forensic investigation work for the firm while providing staff guidance in design, coordination, project management, and construction support. Since joining MHP, Ken has undertaken numerous significant projects as Engineer-of-Record including high and mid-rise hotel and multi-family projects along with significant community college and K-12 work. Additionally, he provides onsite assessments for numerous seismic risk and due-diligence projects.

Kim Caravalho is Vice President of Brandow & Johnston. She has developed long-standing relationships with a number of clients throughout her 25+ years of structural design experience. Working on a wide array of building types and materials, she has experience in the design of new structures, seismic retrofit, modernization, and tenant improvements, as well as DSA plan review. Kim’s portfolio includes K-12 schools, higher education, public facilities, student housing, laboratories, and tenant improvement projects, among others. She is comfortable taking on challenging projects and providing safe, high-quality, and award-winning design solutions for her clients. In addition to being a leader in the office, Kim has also been working with the Board of Professional Engineers, Land Surveyors, and Geologists on various aspects of the exam development for more than 10 years. She earned a Master of Science from the University of Southern California and is licensed in over 15 states.

Tom is president and founder of California Code Check, providing building department services to the government. Prior to California Code Check, Tom’s firm, Harris Engineering, was deeply involved in the inspection, assessment, and recovery from the disaster of the 1994 Northridge earthquake. Tom has a deep commitment to serving and strengthening the cities and counties that he works with and where he is needed. He previously served on the SEAOSC board of directors in 1998-99. He was the SEAOC convention chair in 2006 and 2014 and continues to serve on the convention committee. Tom was named SEAOSC “structural engineer of the year“ in 2015. He was also named Industry Member of the Year by CBOAC in 2014 and by CALBO in 2015. Tom graduated from California State University, Northridge with a Bachelor of Science in Engineering.

Mr. Cuevas has worked for the City of Los Angeles, Department of Building and Safety (LADBS) for 19 years and is currently in charge of Plan Check operations. Prior to this assignment, he managed the department’s Counter Plan Check Operations. He served as the Department’s Code Engineer for 10 years, where he was responsible for amending and adopting the latest California codes and publishing the City’s Building, Residential, Green Code, Electrical, Mechanical, and Plumbing Codes. He has worked and managed Engineering Researched and also worked in plan check, supervised and managed all LADBS plan check offices. Prior to joining LADBS, Mr. Cuevas was an Estimator and Project Manager in general engineering construction and seismic retrofit of buildings for several years where he specialized in structural concrete construction. He holds a B.S. in Civil Engineering from California State Polytechnic University, Pomona, and is a licensed Civil Engineer in the State of California. He is the Past Board President of the Los Angeles Basin Chapter of ICC and a current CALBO Board member. He also served as Planning Commissioner for the City of Montebello for six years.

Ahmed Nasr, S.E., Ph.D. - Simpson Strong-Tie

Deep Shah, S.E. - Tomarco Contractor Specialties dba ISAT

Albina Aouzon - LPA

The SEAOSC Education Committee works towards helping structural engineers improve both their technical and soft skills through webinars, dinner meetings, and full day education events. This year with the challenge of the COVID-19 pandemic, the Education Committee moved all of its events to the online platform and converted the monthly in-person seminars to webinars and virtual panel discussions.

In the upcoming SEAOSC year, our goal is to pursue a hybrid approach with continuation of webinars and organize some in-person seminars and education events when things open up to safely gather for such meet-ups. We are planning for educational topics of interest to our membership and potential presenters for the coming year. We are also looking to collaborate more with the Technical committees of SEAOSC to bring out and present the content that they have been working on and help share with the SEAOSC membership.

The Education Committee provides a unique opportunity to its members to interface with technical experts and industry leaders within structural engineering as well as other industries, such as marketing or finance, all while providing a highly desired benefit to fellow engineers. For anyone interested in joining, the committee welcomes all ideas and supports individual leadership in developing educational programs.

The SEAOSC Education Committee is always open to new members, as well as feedback on past events and suggestions for the future. Please email at education@seaosc.org if you have an interest in helping to organize educational opportunities for our membership or provide feedback.

Engineering Challenges in Hazard Reduction.

Cairo Briceño ¹, Gabriel Acero ², Martin Hudson ³

1)      Chair of SEAOSC Seismology and Hazard Committee, Parsons, Cairo.Briceno@parsons.com

2)      Co-Chair of SEAOSC Seismology and Hazard Committee, AECOM, Gabriel.Acero@aecom.com

3)      Member of SEAOSC Seismology and Hazard Committee, Turner, mbhudson@tcco.com

Seismology and Hazard have been busy in the last years to determine areas that need further development for the practicing engineer and for code development issues. For the practicing engineer, the code is a technical cookbook that needs to be followed literally. Many engineers fulfilling the code requirements as the ultimate goal. For other engineers, code requirements are only the minimum requirements. The Seismology and Hazard committee's goal is to influence the latest code development by interacting with the BSSC, ASCE, IBC, and other national stakeholders. Over the last years, we have placed our interest in several Topics.

Our committee coauthored the 2019 SEAOC Blue Book. The state of the art of design was implemented into the blue book articles as a knowledge resource for code interpretation and best engineer practices. We reflected the standard of care for defining “R” factors for new structural systems within the framework of FEMA 695. We collaborate with other California State Associations in the technical update of several articles of the bluebook. It was during this task, that we took attention to the effect of vertical accelerations on building structures. We looked into earthquake damages observed during past earthquakes: Loma Prieta (1989), Northridge (1994), Kobe (1995), Chi Chi (1999), and Christchurch (2011), can only be attributed to the effects of high seismically induced vertical forces.

We started to revisit ASCE 7-16 regarding accounting for vertical accelerations. Section 11.4.1 defines the near-fault shaking area around the fault surface rupture projection, as a function of the expected earthquake magnitude. For magnitude 7 or larger earthquakes, the near-fault area is defined as 9.5 miles around the fault surface projection area. Although not explicitly described in ASCE 7-16, the near-fault area would be expected to have a potentially larger vertical component due to greater directionality and impulsive characteristics (especially for reverse, normal, or blind thrust fault mechanisms). However, Bozorgia et al research hint that the near-fault distance surrounding the fault should be considered larger than the ASCE 7-16 prescriptive 9.5 miles. The 1994 Northridge earthquake showed that the zone experiencing higher vertical accelerations was more than 9.5 miles from the vertical projection of the fault rupture. The ASCE 7-16 commentary describes the complexity of defining the near-fault influence area where meaningful vertical acceleration will impact the building behavior. From the research data, vertical acceleration has the following characteristics:

The vertical spectral acceleration has been traditionally expressed as 2/3 of the horizontal spectral acceleration. When we apply the combination rule of orthogonal directions using the 100% of horizontal and the 30% of vertical, we came to 0.2 Sds in the ASCE 7-16. A series of case studies were performed using section 11.9 for vertical acceleration. The case studies show that section 11.9 may underestimate the seismic demand. Also, we investigate of vertical acceleration effects on nonstructural MEP, architectural, and fire lines. Currently, we have a subcommittee working on the assessment of those effects versus the prescriptive methods of Chapter 13.

Fig 1. Complex Concrete Core Shear Wall Building

We want to incorporate past earthquake damages due to rebar buckling and rebar fracture during the seismic event within the unified concrete theory from Collins. We are looking into the areas which need to be confined as compression legs at areas of kinematic interaction. The modified compression field theory (MCFT) redefines the shear resistance of wall elements based on strain-stress compatibility to define the concrete areas of the webs and core flanges that collapse in case of the seismic event over the height of the building. It will be defined how many core stories shall need special confinement.

Over the past two years, we also have been investigating the effects of foundation settlement (both static and seismic) on building structures. The effects of foundation settlements require an interdisciplinary view to avoid structural distress over the life span of the structure. It is decoupled into two areas: geotechnical and structural design. In the geotechnical area we have the following components:

To evaluate the effects of settlement the code requires the use of Table 12.13-3 from ASCE 7-16. To evaluate differential settlement ASCE 7-16 provides commentary in Section 12.13.9.2. The key parameter is angular structural distortion due to differential settlement. Once acceptance criteria have been defined, we need to evaluate the appropriate load combination for the computation of long-term deflection. The ASCE appendix CC for serviceability recommends Dead Load+0.50 Live Load as the governing load combination.

Structural engineering practice to mitigate differential settlements:

Structural engineers are typically well educated and informed about the detrimental effects of differential settlements and the devastating effect of the escalation of this phenomena over time which may lead to costly foundation and structural rehabilitations disrupting the normal operations of the structures.

When differential settlements affect a project most of the cases end in legal actions which imply confidentiality requirements that cause extreme difficulties to obtain technical information that could be used for the awareness of the engineering community and to develop design standards.

Plan check reviewers, peer reviewers, and designers are in front of the challenge to account for differential settlements. In the past, the standard practice for the design of the structural systems would have no consideration of differential settlements and still requires the best from the engineers who exercise the profession to address all the requirements in the standards, in addition to the natural interdisciplinary coordination, to name a few: proper material selection for environmental and exposure conditions, serviceability aspects, minimum strength, structural vibration mitigation, gravity and lateral force resisting systems and the corresponding load paths, short term and long term loading, structural detailing, completeness, quality assurance - quality control (QA/QC), etc. The inclusion of differential settlements seems to add a significant extra task for the structural design teams that have not been performed in detail in the past in the average projects and, with rare exceptions, has not been required by authorities having jurisdiction (AHJ). It is obvious that, if not properly planned, accounting for differential settlements may cause budget offsets in structural engineering teams.

The foundation types and total settlements have been traditionally established by Geotechnical engineers at the early stages of the project based on vague concept-level foundation layouts. Traditionally the geotechnical engineer communicates the requirements for analysis and design by estimating the expected differential settlements based on a pre-assigned percentage (in the order of 50%) of the total settlement. Although the structural engineer of record, owner representatives, and authorities of the projects may object to the limits proposed by the geotechnical engineer, it seems a general consensus that the total projected settlement limit is between ½ ” to 1 ½” for shallow foundations and within ¾ ” for pile foundations when subjected to gravity loading under service loading scenarios, depending on the project specifics. The geotechnical engineering team is expected to review the final foundation at the interim stages of the project.

In the current and past practice, with few exceptions, differential settlements are rarely verified except when soil stability issues are clearly identified in the geotechnical report such as liquefaction, subsidence, landslide areas, unstable or collapsible fill layers, etc. The standards have developed to include the evident need to regulate differential settlements in a prescriptive manner (ASCE 7 has included a prescriptive maximum distortion due to differential settlement). The extend of the analysis to satisfy this requirement is still opened to engineering judgment.

The Seismology & Hazards Committee of the Structural Engineers Association of Southern California (SEAOSC-S&HC) is leading an initiative to ease the analysis and identify design strategies intended to mitigate effects of differential settlement at early stages of the project with a reasonable still simplified approach to account for differential settlements (See Figures 4 and 5).

The design guidelines for the identification of potential differential settlements are intended to help architects, planners, structural engineers, plan checkers, peer reviewers, owner representatives, and other construction professionals to identify areas that need a more detailed study to demonstrate the adequacy of the design.

Other topics that we are discussing in the SEAOSC S&H-C in the coming year are: Develop a technical framework to achieve resilience targets. Investigate deformation compatibility requirements for CLT and Steel gravity members under imposed nonlinear seismic drift. Fire Hazard. Tsunami Hazard in Coastal areas. We met at the end of the month. You can contact us at seismology@seaosc.org

Communications Committee

Chair: Maria Mohammed communications@seaosc.org

Diversity & Inclusion Committee

Chair: Lorena Arce

Education Committee

Chair: Siddharth Awasthi

Membership Committee

Chairs: Kerry Regan / Christian Cody

Younger Members Committee

Chair/s: Jessica Chen / Sikandar Porter-Gill

Women in SE Committee

Chairs: Michelle Kam-Biron

Codes & Standards Committee

Chairs: Colin Kumabe / Michael Ciortea

Concrete Committee

Chair: Dragos Ursu / Nils Fox

CMU Committee

Forming - Contact President if Interested

New Buildings Committee

Forming - Contact President if Interested president@seaosc.org

Specialty Materials Committee

Forming - Contact President if Interested

Steel Committee

Chair: Ashwani Dhalwala

Wood Committee

Chair: Zizhao (Zee) He

Disaster Emergency Services Committee

Chairs: Laura Basualdo / Doug Litchfield

Legislative and Professional Practices Committee

Chair: Daniel Wang

Safer Cities Initiative Committee

Organized through Codes & Standards

Sustainability / Resilience Committee

Chair: Timothy Saenz