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Vibration of Steel Joists with Flush Frame End Connections

Steel joists with flush framed end connections enhance floor vibration properties.

Recent floor vibration measurements and research completed by Vulcraft have shown that flush frame joist end connections can have a significant positive impact on a floor’s vibrational response when subjected to walking excitation. This article shows how the frequency and effective mass of the floor bay can be changed dramatically when switching from traditional bearing seats to flush frame connections developed by Vulcraft. Manual calculation procedures found in the American Institute of Steel Construction (AISC) Design Guide 11, 2nd Edition, Vibrations of Steel-Framed Structural Systems Due to Human Activity and the Steel Joist Institute’s (SJI) Technical Digest 5, Vibration of Steel Joist – Concrete Slab Floors (hereafter referred to AISC DG11 and SJI TD5) currently do not address steel joists with flush end connections. This article demonstrates how the provisions in AISC DG11 and SJI TD5 can be used for flush frame connections.

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Nov, 2023 By David Samuelson, P. E., Brad Davis, Ph. D., S. E. and Thomas M Murray, Ph. D., P. E. In Structural Connections

Mentoring is for the Birds

Early in my college career I recall taking several required arts and science courses and certain required elective courses. A specific memory comes to mind regarding a book report the class was assigned midway through the semester in which I had to write an expository essay. I must have done an awesome job on the essay as I received an “A.”

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Nov, 2023 By Cervente Sudduth P. E., ENV SP In Editorial

2024 IBC Significant Structural Changes

Roof assemblies (Chapter 15)—Part 1.

This multi-part series discusses significant structural changes to the 2024 International Building Code (IBC) by the International Code Council (ICC). Part 1 includes an overview of changes to Chapter 15 on roof assemblies. Only a portion of the chapter’s total number of code changes are 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 (Figure 1).

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Nov, 2023 By John “Buddy” Showalter, P. E., M. ASCE and Sandra Hyde, P.E. In Code Updates

HSS Availability

Checking the availability of HSS sections is easy with the Steel Tube Institute’s Capability Tool.

If you have ever opened the steel manual to find section properties for a steel HSS (hollow structural section) member, you may have been surprised by how many sizes of HSS are listed. There are hundreds of options for round, rectangular, and square tubes. Some of these sections are readily available, others are produced on demand, and some may not be available in the current market. Realizing this, the Steel Tube Institute (STI), an industry organization supported by domestic steel tube producers, has created a free Capability Tool as a resource to search which HSS sections are currently domestically produced, by whom, and whether the sections are regularly produced or produced on demand. At steeltubeinstitute.org/capability-tool, there are search fields for shape, dimension range, and grade. Three ASTM (American Society for Testing and Materials) HSS material grades are included: A500, A1085, and A1065; and one for mechanical tubing, A513. Once these fields are filled, a list of producers who provide that shape, either regularly or on demand, is generated.

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Nov, 2023 By Beth Suminski and Cathleen Jacinto In InSights

Design of Stainless Steel Bolted Connections in Accordance With the Recently Published ANSI/AISC 370

Design rules for bearing-type and slip-critical bolted connections made of stainless steel are now available.

In the December 2022 edition of Structure Magazine, Benjamin Baer gave an overview of the new AISC design specification for structural stainless steel, ANSI/AISC 370, and introduced the provisions for designing members. This article focuses on the design of bolted connections in structural stainless steel.

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Nov, 2023 By Francisco Meza, Ph. D. and Nancy Baddoo In Structural Design

San Francisco–Oakland Bay Bridge

One of America’s greatest bridges, carrying the heaviest traffic in Northern California.

The San Francisco–Oakland Bay Bridge (henceforth, Bay Bridge), completed November 12, 1936, during the Great Depression, remains one of the world’s greatest bridges. Together with its neighbor, the Golden Gate Bridge, it represents the culmination of more than 100 years of bridge engineering development in the US. After its opening, the bridge, which connects San Francisco and Oakland, soon became known as the “workhorse of Northern California,” carrying the heaviest traffic in the region. As part of Interstate 80, it remains the busiest traffic link in Northern California carrying on its two decks up to 280,000–300,000 vehicles per day, or more than 13,000 per peak hour.

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Nov, 2023 By Roumen V. Mladjov, S.E., P.E. In Iconic Structures

19th Century Mississippi River Bridges #9

Winona bridge, Minnesota/Wisconsin 1871.

The Winona and St. Peter Railroad (originally the Transit Railroad Company) was founded in 1862 and planned to run westerly from Winona on the Mississippi River to St. Peter, about 125 miles away, reaching that point in 1871. From there, it reached Watertown, South Dakota, in 1873. In 1867, it was purchased by the Chicago and North Western Railway that was chartered on June 7, 1859, and from Chicago, it reached the Mississippi at a point in Wisconsin east of Winona, Minnesota, in 1873. It continued its route north to St. Paul, connecting with the Northern Pacific Railroad heading for the West Coast at Puget Sound. However, a bridge connecting the two lines, now under the control of the Chicago and North Western Railway, was needed. After a five-year battle, approval was given to build the bridge in accordance with the 1866 federal law prescribing the requirements for a low-level and a high-level bridge as described for the Quincy and other bridges. Section 8 of the July 25, 1866 Act stated,

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Nov, 2023 By Frank Griggs, Jr., Dist. M. ASCE, D. Eng., P.E., P.L.S. In historical Structures

Thoughts on Computer-Based Testing

A young engineer’s perspective on how computer-based testing can impact the engineering profession.

Change is scary, and so is the PE Structural Exam. Will changing the PE Structural Exam be a nightmare? Moving the exam from a paper and pencil format to a computer-based testing (CBT) approach has caused quite a stir in the profession; however, it might not be as bad as has been hyperbolized. These changes will have a direct impact on the engineering profession, especially on young engineers like me. While there are concerns and room for improvement, these modifications could serve as a way to improve the examination process and provide a more achievable path towards S. E. licensure.

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Oct, 2023 By Orion R. Paul, P. E. In Structural Perspective

19th Century Mississippi River Bridges #8

Keokuk & Hamilton bridge.

This bridge between Keokuk, Iowa, and Hamilton, Illinois, was one of the eight Mississippi River sites approved by Congress and signed by President Andrew Johnson on July 25, 1866. As such, it had to abide by the requirements for a low-level bridge with a swing span or a high-level bridge with specified horizontal and vertical clearances. The Hancock County Bridge Company received its approval from the Illinois legislature on February 13, 1865, and the Keokuk and Hamilton Mississippi River Bridge Company received its approval from the Iowa Legislature on January 15, 1866. Based upon a survey in 1867, the city of Keokuk in 1868 granted a right-of-way across the levee.

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Oct, 2023 By Frank Griggs, Jr., Dist. M. ASCE, D. Eng., P.E., P.L.S. In Historic Structures

FAQ on SEI Standards

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). In addition, questions from engineers, building officials, and other design professionals are often considered to develop future editions. Following are some questions received by SEI and responses to clarify the provisions.

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Oct, 2023 By Jennifer Goupil, P.E. In Codes and Standards

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