Galloping Gertie, Part 1
The collapse of the Tacoma Narrows Bridge is one of the most well-known of all bridge failures as its collapse was caught on film. The film was and still is viewed in many introductory physics classes.
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As we move into 2022, we all understand that things have changed for everyone, everywhere. And just as our personal and professional lives have changed, so must our approach to hiring and retention.
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While previous articles in STRUCTURE have looked at specific contract provisions – for example, the Waiver of Consequential Damages in the November 2021 issue – this article discusses contracts in general.
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Over the last few years, Virtual Reality (VR) has moved from a gimmick to a valuable tool in the construction industry.
Studies show that a large and unnecessary part of a construction budget is typically allocated towards fixing mistakes made during planning and execution or correcting bad solutions after work is completed. The root cause of this is a lack of clear communication among stakeholders. The cost of fixing completed work becomes more expensive late in the project. Too often, it results in either high costs or sub-optimal solutions for the end-user. A large percentage of these issues can be prevented with clear and understandable communication early in the project.
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Creative Solutions for a National Historic Landmark
Nestled between university housing and hospitals in Madison, WI, is a building that, even among equals, distinguishes itself as a monument to architecture. A National Historic Landmark, the First Unitarian Society Meeting House was designed by Frank Lloyd Wright and completed in 1951. The building’s auditorium is supported by center-hinged wood trusses spanning up to 76 feet near the entrance, down to 12 feet at the building’s iconic prow. Trusses bear on stone piers and walls. Wright restricted himself to using 2×4s and occasionally 2×6s. The contractor later commented that Wright wanted to “build that church with toothpicks,” a statement that would become apparent over the next 60 years.
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Structural engineers neglect a key tenet of their professional obligation to society – designing for sustainability. While the concept of sustainability spans the social, economic, and environmental domains (the so-called triple bottom line), immediate action in the environmental domain is required in the face of the climate crisis, specifically around greenhouse gas emissions. Anthropogenic greenhouse gas emissions (e.g., carbon dioxide and methane) are causing global temperatures to increase, resulting in increased frequency and severity of weather events, impacting infrastructure in the United States and worldwide. According to the Intergovernmental Panel on Climate Change (IPCC), all sectors, including buildings, must decarbonize (have net-zero carbon emissions) by 2050 to avoid a 1.5 degree C (2.7 degrees F) temperature rise. However, today, the manufacturing of construction materials for buildings contributes to 11% of global greenhouse gas emissions. Thus, to achieve a decarbonized built environment, structural engineers must consider strength and serviceability when designing structural systems and commit to mitigating their greenhouse gas emissions.
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By the time you are reading this, the 2021 election season is behind us. Although the recent elections did not have national office implications, offices for elected officials were likely held where the reader lives. Did you participate in any way? Did you take the opportunity to vote? Have you ever considered running for elected office?
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Part 1
Concrete buildings with vulnerable columns are some of the most dangerous structures when earthquakes occur. Since the 1970s, building codes have addressed the detailing of columns that are part of moment frames in high-seismic regions. Research for the Portland Cement Association [Blume et al., 1961] and subsequent studies in New Zealand established the need for close spacing of ties and a capacity design of frame members for shear strength sufficient to cause flexural yielding rather than undesirable shear failure.
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Part 3: Special Inspections (Chapter 17)
This five-part series (Part 1, STRUCTURE, November 2021, Part 2, December 2021) includes discussion of significant structural changes to the 2021 International Building Code (IBC) by the International Code Council (ICC). This installment includes an overview of changes to Chapter 17 on special inspections and testing. Only a portion of the total number of code changes to this chapter are discussed in this article. More information on the code changes discussed here can be found in the 2021 Significant Changes to the International Building Code, available from ICC (Figure 1).
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What You Always Wanted to Ask
Welcome to this new quarterly column for STRUCTURE magazine. These articles will address some of the questions received (along with responses) about structural standards developed by the Structural Engineering Institute (SEI) of the American Society of Civil Engineers (ASCE), such as ASCE 7 and ASCE 41. Questions received from engineers, building officials, and other design professionals are often considered for the development of future editions. Following are some questions received by SEI as well as responses to clarify the provisions.
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