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Blast Protection of Buildings

Revisions to ASCE/SEI 59

The events of 9/11 changed many owners’ perceptions of the risk to their facilities. Their fear of malicious threats thrust practicing structural engineers into an unfamiliar role. As a result, structural engineers needed to learn how to quantify and analyze for blast effects as they assisted their private clients with the evaluation of threats to their facilities and the means to provide prudent, reasonable, and effective resistance. In response, the Structural Engineering Institute (SEI) of the American Society of Civil Engineers (ASCE) developed a new standard, ASCE/SEI 59 Blast Protection of Buildings (ASCE 2011), describing how engineers could design blast resistance into structures.

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Oct, 2022 By Donald O. Dusenberry, P.E., SECB, F.SEI, F. ASCE In Structural Performance Comments 0

ASCE 7-22 Changes to Component and Cladding Wind Provisions

Revised Component and Cladding (C&C) wind load provisions in ASCE 7-22, Minimum Design Loads and Associated Criteria for Buildings and Other Structures, produce in most cases either the same or slightly lower pressures than would occur under the prior edition while also preserving the extensive wind tunnel testing basis of the ASCE 7-16 C&C wind provisions.

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Oct, 2022 By William L. Coulbourne, P.E., M. ASCE and Philip Line, P.E. In Code Updates Comments 3

Fall Protection Anchorage Design Insights

The design of structures utilized to support fall protection systems (FPS) for workers at height is a topic that is often researched and questioned but is not a straightforward process. Unlike other common structures with design requirements such as loads, factors of safety, and minimum requirements defined in their respective codes and design guides, the design requirements for fall protection loads can be somewhat ambiguous. This article aims to provide a basic overview of FPS, define what regulations and standards exist in this space, and recommend a best practice approach for engineers to define strength requirements for fall protection anchorages.

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Oct, 2022 By Heidi Lopez-Hidalgo, P.E. In Structural Connections Comments 2

Numerical Simulations of Bored Piles

Bored piles primarily carry static vertical loads when supporting a building. In designing such piles, the shaft resistance and end bearing are often estimated when determining the pile’s load-carrying capacity. To ensure satisfactory performance, the pile also needs to meet specific settlement criteria at working loads. One helpful aid in pile design is using numerical simulations. With advances in computing, access to numerical simulations has become widely available and often quite economical. This article highlights some practical aspects of numerical simulations which can be helpful in pile design.

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Oct, 2022 By Hee Yang Ng, MIStructE, C.Eng, P.E. In Structural Modeling Comments 0

Horizontal Diaphragm Seismic Design

Using ASCE/SEI 7-22

Designers using the 2022 Edition of the ASCE/SEI standard Minimum Design Loads and Associated Criteria for Buildings and Other Structures (ASCE/SEI 7-22, ASCE, 2022) will find significant changes to the seismic design of diaphragms and their chords and collectors: a new diaphragm design methodology added, an existing methodology expanded, significant changes affecting bare steel deck diaphragms, and more. This leaves the user needing to choose between three methods of diaphragm seismic design and needing to incorporate other updates into their designs. The changes were generated from research and code development efforts that go back years, with contributions from many, including research and guideline development teams and the NEHRP and ASCE 7 update participants. This article provides an overview of these changes to diaphragm seismic design from the designer’s perspective.

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Oct, 2022 By Kelly Cobeen, S.E. In Structural Design Comments 0

FAQs on ASCE Standards

What You Always Wanted to Ask

This quarterly article addresses some of the questions received about structural standards developed by the Structural Engineering Institute (SEI) of the American Society of Civil Engineers (ASCE). Following are some questions received by SEI and responses to clarify the provisions. Questions from engineers, building officials, and other design professionals are often considered to develop future standard editions.

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Oct, 2022 By Laura Champion, P.E., F.SEI, F.ASCE and Jennifer Goupil, P.E. In Just the FAQs Comments 0

Dennis Nottingham

Alaska’s Bridge Builder

Dennis Nottingham, P.E., was a bridge builder. “I designed a lot of bridges, the big ones. The Yukon. The Gulkana. I worked on every single bridge – construction bridges, access bridges – on the Trans-Alaska Pipeline in some form or another,” Nottingham said during his company’s 40^th-anniversary celebration in 2019 in Anchorage. His Hall of Fame biography credits Nottingham with more than 300 bridge designs in Alaska.

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Oct, 2022 By Aaron Unterreiner In Pioneers in Engineering Comments 0

Rock Island Bridge 1856

19th Century Mississippi River Bridges Series

As early as 1842, some early promoters of the Transcontinental Railroad selected a route that would cross the Mississippi between Rock City, Illinois, and Davenport, Iowa. They chose this site based on a survey in 1837 by Lt. Robert E. Lee, as the river was narrow and separated by Rock Island, the home of a former army fort. This would require a bridge over each branch and an embankment across the island. In 1850, Congress passed an act granting public lands to railroad companies to encourage the country’s development. Congress also passed an act, in August 1852, granting a right-of-way for rail and plank roads on public lands.

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Oct, 2022 By Frank Griggs, Jr., Dist. M. ASCE, D. Eng., P.E., P.L.S. In Historic Structures Comments 0

The Little Island Pier

Collaborative 3-D Modeling Critical to Success

Little Island is an artificial island built on the Hudson River, providing a unique park experience for New Yorkers and tourists, including open space, nature, art, entertainment, and education. Its signature design distinguishes it from other piers with complex curved geometry, undulating and landscaped grade elevation, and irregular-looking pile grids. However, the design also imposed the most significant challenges for the structure and construction. Arup, the design team, quickly realized that the only solution to ensure that the geometry of construction would align on site would be a common design and construction model. Therefore, the team adopted an open approach to 3-D modeling and digital information transfer and incorporated direct-to-manufacturing digital fabrication techniques.

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Oct, 2022 By STRUCTURE magazine In Spotlight Comments 0

The Electric Power Grid: The Times They Are A-Changin’

“Come gather ’round people wherever you roam and admit that the waters around you have grown and accept it that soon you’ll be drenched to the bone. If your time to you is worth savin’, then you better start swimmin’, or you’ll sink like a stone for the times they are a-changin’.” – Bob Dylan

Times in the electric utility world seem to be more rapidly a-changin’ than ever before. Why you may ask, do I mention the electrical utility industry in STRUCTURE magazine? While it is obvious that Electrical Engineers are the beating heart (at 60 Hz) of the electric power grid, Civil and Structural Engineers add the bones and create the muscle that helps give the grid its strength, durability, and, dare I add, resiliency? The challenges facing the electric power grid are unique and unprecedented. As the Bob Dylan refrain elaborates, the waters of change are growing and we… better start swimmin,’ or you’ll sink like a stone!

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Sep, 2022 By Wesley J. Oliphant, P.E., F.SEI, F.ASCE In Editorial Comments 1

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