Wind & Tornado Part 1

Introduction

• Introduction of esteemed colleagues to the session.

Cherilyn Henry

• Role: Structures Group Lead and Project Manager at Zapata.

• Credentials:

  • Licensed Professional Engineer.

  • 17 years of design experience in buildings and bridges.

• Committee Involvement:

  • Member of ASC 7 wind load subcommittee since 2012.

  • Served as Secretary for the 716 cycle.

  • Served as Vice Chair for the 722 cycle.

  • Member of the ASC 7 main committee.

  • Served on multiple SEI board level committees.

  • Currently a member of the ASCE codes and standards committee.

• Education:

  • BSAS in MR Architecture from the Structural Engineering Program at the University of Illinois Urbana-Champaign.

  • BSCE from Arizona State University.

• Role in Session: Moderator.

Dawn Scott

• Role: Senior Consultant with PCS Structural Solutions.

• Credentials:

  • Licensed Professional Instructional Engineer.

  • Over 40 years of experience in design, evaluation, rehabilitation, and building structures.

• Committee Involvement:

  • Principal Investigator for the SEI prestandard for performance-based wind design.

  • Chair of the SEI codes and standards executive committee.

  • Chair of the ASCE 7 wind load subcommittee.

  • Member of the ASCE 7 main committee.

  • Currently President-elect of the SEI board of governors.

• Awards:

  • James Delehay Memorial Award from NCSEA.

  • Walter P. Moore Jr. Award from SEI for contributions to codes and standards development.

Mark Levitan

• Role: Lead Research Engineer for the National Windstorm Impact Reduction Program at NIST.

• Notable Work:

  • Lead investigator for the NIST investigation of the 2011 Joplin, Missouri tornado.

  • Worked on the NIST study of the 2013 Moore, Oklahoma tornado.

• Current Initiatives:

  • Chairing the task committee for tornado provisions in ASCE 722.

  • Developing the ICC 500 storm shelter standard for the 2023 edition and earlier.

  • Co-chairing the ASCE SEI and AMS committee on new standards for wind speed estimations and tornadoes.

Poll Results

• Attendee Experience Levels:

  • Most attendees have significant experience:

  • 6-15 years

  • 16-25 years

  • Majority: More than 26 years.

• Type of Organizations Represented:

  • Predominantly consulting firms.

  • Some academia and government representation.

  • Few producers and students.

• Familiarity with ASCE 7:

  • Majority very familiar and frequently use the standard.

• Encouragement to Utilize Q&A Box:

  • Attendees encouraged to ask questions during the session.

ASCE 7 Adoption Process

Introduction by Cherilyn Henry

• Discussion on the adoption of ASCE 7 through the International Building Code (IBC).

• Importance of understanding how ASCE 7 is used in practice.

Explanation by Dawn Scott

• Process Overview:

  • ASCE 7 is referenced in the IBC rather than directly included.

  • Significant parts of the U.S. adhere to the IBC, necessitating the adoption process.

• Importance of the adoption process:

  • Annual hearings where proposals are submitted for new ASCE editions.

  • Presentations made to the committee, which recommends changes.

  • Comments from the public must be addressed before final approval.

• Current Status for ASCE 7-2022:

  • Committee action hearings have occurred.

  • Recommendations made for adoption into the 2024 IBC.

  • Upcoming public comment stage and final action hearings in September.

Usage of ASCE 7 Before Official Adoption

• Discussion on whether jurisdictions can use ASCE 7-2022 before IBC official adoption.

  • Conclusion:

  • Building officials often allow the use of updated provisions ahead of formal adoption, emphasizing that all provisions used must come from the same chapter of the code.

  • Communication with local authorities is key to utilizing new provisions early.

Reasons for Growth of ASCE 7

Question by Cherilyn Henry

• Inquiry regarding the increasing length of the ASCE 7 standard.

Explanation by Dawn Scott

• The growth of the standard is influenced by various industry needs:

  • While aimed to simplify, practitioners often request additional provisions for clarity and competence, contributing to expansion.

  • The shift towards more prescriptive guidelines versus performance-based approaches has led to increased page counts.

• Historical Context:

  • About 180 members applied for the Wind Load Subcommittee with high attendance at meetings.

  • A desire for more detailed provisions arises, adding complexity rather than reducing it.

• Recent Innovations:

  • Rapid industry changes necessitate regular updates to include new technologies such as wind provisions for solar panels.

• Future Direction:

  • Ongoing research and development, including wind tunnel studies, could simplify and reduce future iterations of the standard, potentially merging chapters to streamline calculations.

Introduction of Tornado Provisions

Introduction by Cherilyn Henry

• Transition into tornado provisions discussion led by Mark Levitan.

Tornado Design Methodology

Explanation by Mark Levitan

• Background: Work initiated post-2011 Joplin tornado, leading to recommendations for enhanced tornado preparedness.

  • Notable event statistics:

    • 161 fatalities.

    • $3 billion in insured losses.

    • Nearly 8,000 structures damaged or destroyed.

• Objective of Recommendations:

  • Development of new probabilistic tornado hazard maps.

  • Creation of a performance-based tornado design methodology.

• Implementation Timeline:

  • Nearly a decade of research and development with collaboration from experts in the field.

• Technical Adjustments:

  • Basic wind load formulation retained but many parameters adjusted.

  • Overall design approach aimed to remain familiar yet include necessary innovations.

• Community Engagement:

  • Initial resistance to including tornado loads in ASCE 7 identified; the consensus shifted towards necessity based on new research.

  • Arguments focused on prevalence of tornadoes and their impact on building safety.