Review Category : Articles

By John “Buddy” Showalter, P. E., M. ASCE, M. NCSEA, and Sandra Hyde P. E., M. ASCE, M. NCSEA

This multi-part series discusses significant structural changes to the 2024 International Building Code (IBC) by the International Code Council (ICC). Part 5 includes an overview of changes to IBC Chapter 16 regarding risk categories. Only a portion of the chapter’s total number of code changes is discussed in this article. More information on the code changes can be found in the 2024 Significant Changes to the International Building Code available from ICC.

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By Brian MacRae, P.E., S.E., Kerem Gulec, Ph.D., P.E., S.E.

The ambitious goal of transforming the existing Key Arena in Seattle, Washington, into a world-class sports and concert venue was undertaken by its owners at Oak View Group, who challenged the project team to develop numerous innovative and collaborative solutions. Opened in October 2021, Climate Pledge Arena is home to the NHL’s newest franchise Seattle Kraken and WNBA’s Seattle Storm. The total transformation of the venue serves as a structural engineering benchmark for existing building renovations in high seismic zones and demonstrates what can be accomplished with modern design and analysis techniques.

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By John McDonald, S.E., Stefanie Chamorro, P.E., and Geoff Bomba, S.E.

Driven by the importance of the Oregon State Capitol and disproportionate seismic damage from the 1993 Scotts Mills seismic event, the Oregon Legislature moved forward with measures to protect and preserve the historic building. The project includes a seismically base-isolated retrofit of the 1938 Capitol building, which is a non-ductile brick infilled concrete frame structure with marble cladding. The Capitol is flanked by a pair of five-story 1977 reinforced concrete buildings retrofitted using a fiber-reinforced polymer (FRP) strengthening system, which remain fixed base structures. The seismic isolation system of the Capitol utilizes a triple friction pendulum system tuned to reduce the acceleration of the building during a Cascadia Subduction Zone (CSZ) seismic event. Once complete, a new occupied level will be constructed below the existing building footprint to increase program space and meet the changing needs of the Oregon State Capitol.

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By Seth Thomas

Special Wind Regions (SWR) are defined in ASCE 7-22 Section 26.5.2. as “Mountainous terrain, gorges, and special wind regions shown in Figure 26.5-1.” These regions are identified in ASCE 7 to highlight the lack of data or the high variability of wind speeds in localized areas where the wind data from the surrounding areas may not be adequate to properly capture the hazard.

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By Duane K. Miller

Many welds are evenly loaded: the applied loads are uniformly transferred through the throat and length of the welds. Such welds are easily designed and routinely perform as expected. Other welds, however, are unevenly loaded. One end of the length of the weld may be more severely loaded than the other, or the loading along the weld throat may be non-uniform. The design of these welded connections is more complicated.

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By Kyle A. Karschner P.E., S.E., Jacob Sun, P.E., and Michael F. Hughes, P.E., S.E.

Building owners are turning to adaptive reuse of existing buildings to meet the market demand for alternative uses, such as life science, data, robotics, and other tech-related industries. These uses typically require upgrading the building’s mechanical, electrical, plumbing, and fire protection (MEP-FP) systems that use larger and heavier equipment than the building’s original structural design. As a result, this work can trigger costly structural upgrades for strength, serviceability, or both to comply with building code requirements.

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By Timothy R. Donahue, P.E.

Generally speaking, for a given structure, the higher the seismic response factor (R) value is, the more ductile the structure is and the lower the total seismic load acting on the building. With this concept in mind, one might conclude that reducing the seismic load acting on a building by selecting a more ductile seismic force restraint system (SFRS) with a higher R value would ultimately lower the material cost; however, when evaluating the overall cost implications for what it takes to achieve the increased ductility, the cost savings may not always be realized. This is primarily due to the requirements of overstrength factors in the design and detailing of the straps and other protected components of the SFRS with an R greater than 3.

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By John Worley, S.E. and Pierre Quenneville, Ph.D

“Residual drift” is the permanent lateral deformation of a building following an earthquake (Figure 1). In high seismic regions, buildings designed per code utilizing ductile seismic force resisting systems defined in ASCE 7 could experience excessive residual drifts in a major earthquake that may result in a damage level deemed to be uneconomical to retrofit and therefore be demolished.

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By Jerome F. Hajjar, Ph.D., P.E., NAE, F.SEI, F.ASCE

The construction and operation of the built environment accounts for a large portion of global greenhouse gas emissions. Governments, owners, occupants, architects, and engineers increasingly recognize the centrality of the structural engineering profession in our collective efforts to mitigate climate change. The United Nations (UN), through the Conference of Parties (COP) yearly intergovernmental summit aimed at creating global cooperation on issues of mitigating climate change, met in December 2023 in Dubai for COP28, at which they continued development of a Breakthrough Agenda.

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