Joists and joist girders can efficiently transfer diaphragm chord forces to shear walls and lateral frames, but the specifying professional must give due consideration to the connection details. Transferring forces through the joists can induce eccentricities at the bearing seat which can lead to unintended moments on the bearing seat.  Have you considered the most efficient way to detail the bearing seat connection when transferring chord forces?

In the November 2023 SEU session, Darrell Marchell, PE, from Vulcraft, and Tim Holtermann, PE, SE, from Canam Steel, on behalf of the Steel Joist Institute, presented Lateral Load Resisting Frames for Steel Joist and Joist Girders.  Darrell and Tim identified how open web steel joists and joist girders can be used in different lateral load resisting systems.  They explained how to effectively specify loads on the contract documents, shared commonly used connection details, and advised ways to reduce manufacturing and construction costs for different systems.

Tim offered several tips for efficient connections that transfer the diaphragm chord forces without compromising the joist bearing seat.  One option, shown in the slide below, is a joist tie plate running across the top of the joists at the location of bearing.  SJI recommends the plate width be limited to 4 inches so as to leave room for a downhand weld to the joist top chord and to limit the weld size to 3/16 inch to prevent having to increase the top chord thickness to accommodate a larger weld.

 

An alternative option could be to use joist tie angles which run on the underside of the top chord.  This detail eliminates any interruption or bumps in the steel decking, however an increased seat depth may be required to accommodate the tie angles, as shown in the connection detail below.  SJI recommends using 3/16 inch welds for joists and ¼ inch welds for joist girders with longer welds, as needed.

For an exterior location, where the chord forces may create an end moment due to the eccentricity at the bearing seat, an axial transfer rod, as shown below, can be used to transfer the chord force directly from the top chord to the bearing seat.  Also, two axial transfer rods can be added to each side of the joist or joist girder if needed to transfer this axial force.

 

Darrell and Tim noted the joist top chord contributes the most to the expense of the truss, so the specifying professional should heed these recommendations to avoid any unnecessary cost increases in the truss due to inefficient connection details.  Diaphragm chord forces can induce significant moments, so specifying professionals need to indicate how they intend to transfer these forces appropriately.

 

In October 2023, Carol Drucker, SE, PE, from Drucker Zajdel Structural Engineers, Inc., presented Vertical Bracing.  She selected Purdue University’s Robert L. and Terry L. Bowen Laboratory for Large-Scale Civil Engineering Research (Robert L. and Terry L. Bowen Laboratory for Large-Scale Civil Engineering Research (purdue.edu)) for the SEU Speaker Inspires donation of the month.

This 66,000 square-foot facility provides the space and technical capability needed to investigate the behavior of large structural models and elements subjected to loads representing extreme events, such as earthquakes, blasts, and impact, so that future structures will be designed to better withstand these extreme events. The lab’s “strong floor,” clear ceiling height of 54 feet, loading apparatus, and advanced instrumentation set a new standard for materials and structures testing.

Thank you, Carol, for helping structural engineers with your SE University session, and for your designation of the Purdue University’s Robert L. and Terry L. Bowen Laboratory for Large-Scale Civil Engineering Research as our SEU Speaker Inspires Organization of the Month!

 

 

SE University began the SEU Speaker Inspires program in 2015 as a way to “pay it forward”, enabling our speakers to designate a charity/organization of their choice for SE University to make a donation to help improve our world.

In September 2023, John Kennedy, SE, PE, from Structural Affiliates International, Inc., presented Rules of Thumb for Steel Design.  He selected St. Jude Children’s Research Hospital (St. Jude Children’s Research Hospital (stjude.org)) for the SEU Speaker Inspires donation of the month.

John shared, “I chose this organization because I support and believe in their mission to advance research, treatment, and prevention of pediatric catastrophic diseases. It’s headquartered in my home state of Tennessee, and I admire the help the organization brings to both children and families who may be in dire need of support.”

Thank you, John, for helping structural engineers with your SE University session, and for your designation of the St. Jude Children’s Research Hospital as our SEU Speaker Inspires Organization of the Month!

 

 

SE University began the SEU Speaker Inspires program in 2015 as a way to “pay it forward”, enabling our speakers to designate a charity/organization of their choice for SE University to make a donation to help improve our world.

Digital notifications, chatty co-workers, and news alerts… Text messages, internet searches, and phone calls… With attention spans declining and distractions on the rise, what can we do to reclaim our focus in 2024?

There are many ways we can improve our focus, but all methods aim to reduce distractions.  Set small goals initially, and then work toward implementing some changes to your daily routine.  These changes may include forming a detailed schedule and assigning time limits for various tasks and breaks, using alarms to stay on schedule, setting digital notifications to “Do not disturb” while engaged in a task, or creating time for exercise breaks to boost your energy throughout the day.  One trick to eliminate falling into the digital rabbit hole of endless news alerts or social media stories might be to include a small reward, such as a coffee refill or quick check in with a coworker, when you successfully end your scheduled time set aside for scrolling on your devices.  Creating a list of daily priorities might be necessary, and then any less important or distracting tasks that pop up throughout the day can be added to the bottom of the list, to be addressed at a later time.  Focus has also been shown to improve when we make healthy choices such as minimizing sugary foods, getting enough sleep at night, and reading or meditating outside of work.

Interruptions are unavoidable, but establishing a plan to maximize productivity and minimize distractions can improve our ability to focus, especially while at work.  Keep it simple and adopt a few changes to your daily routine, and see how your focus returns in 2024!

How many times have you been in a kick-off meeting, and the architect is already pressing you to offer up beam and column sizes for the building in question?  Or how do you usually answer when prompted to estimate the total steel tonnage on a project for preliminary cost estimates?

In the September 2023 SEU session, John A, Kennedy, SE, PE, from Structural Affiliates International, Inc.presented Rules of Thumb for Steel Design.  John shared some quick reference approximations for mechanical properties of steel sections.  He also identified some rules of thumb for the design of beams, columns, and trusses, and shared some design examples using these rules. 

John offered an excellent resource which includes many of these quick reference rules in the form of a printable pocket card.  Using this card, engineers can make on-the-spot determinations during meetings or preliminary design to get a reference for the size of beam or columns needed.  Click here to print your own copy.

The reference card uses units of measurement that engineers typically use, such as weight in pounds, area in square inches, and axial capacities in kips.  The card offers all of the economy steel sections as well as the column widths for common sizes.  The equations that are shaded can be used for 50 ksi steel.  

John noted that rules of thumb are approximations and are not always conservative.  Using these approximations should in no way take the place of a rigorous structural analysis; however, these rules of thumb are quick, easy to use, and really simplify some basic calculations to make useful approximations when time is of the essence.

As 2023 comes to a close, we would like to wish the entire structural engineering community a wonderful holiday season. We have enjoyed another year of providing excellent services and educational content while supporting many charitable organizations to pay it forward to a better 2024. Stay safe and healthy, and we look forward to the opportunity to meet your structural engineering needs in the New Year!

In August 2023, Kimberley Robinson, SE, from EVER Seismic, presented It’s Better to Bend than Break: Retrofit with Buckling Restrained Braces.  She selected the YWCA Utah Women in Jeopardy Crisis Shelter (YWCA Utah) for the SEU Speaker Inspires donation of the month.

Kim shared, “The YWCA Women’s Shelter provides safety and sanctuary to those fleeing domestic violence. They offer women and children safety and support to empower them and give them a chance to thrive. I walked those halls for a time as a child and will never forget what they did for my mother and us. They make a profound difference in lives every day.”

Thank you, Kim, for helping structural engineers with your SE University session, and for your designation of the YWCA Women in Jeopardy Crisis Shelter as our SEU Speaker Inspires Organization of the Month!

 

 

SE University began the SEU Speaker Inspires program in 2015 as a way to “pay it forward”, enabling our speakers to designate a charity/organization of their choice for SE University to make a donation to help improve our world.

Emily Guglielmo, PE, SE, Martin/Martin

In June 2023, Emily Guglielmo, PE, SE, from Martin/Martin, presented ASCE 7 Frequently Asked Questions (Seismic). She nominated LeaderFlow (LeaderFlow – Leadership for AEC professionals) for the SEU Speaker Inspires donation of the month.

Emily shared “I chose LeaderFlow because Structural Engineering has been significantly underrepresented by diverse leadership, and there are still challenges with retaining diverse talent. One large gap in this career pipeline is the opportunity for mid-career professionals, especially those of color to access vital leadership development training and LeaderFlow is working to close that gap.”

Thank you, Emily, for helping structural engineers with your SE University session, and for your designation of LeaderFlow as our SEU Speaker Inspires Organization of the Month!

 

 

SE University began the SEU Speaker Inspires program in 2015 as a way to “pay it forward”, enabling our speakers to designate a charity/organization of their choice for SE University to make a donation to help improve our world.

Have you ever been in a project meeting and needed to make a quick estimation of beam sizes without any reference books?  Experience alone can sometime suffice, but a quick rule of thumb can be helpful to determine the beam weight needed for a given loading condition.

In the September 2023 SEU session, John A, Kennedy, SE, PE, from Structural Affiliates International, Inc.presented Rules of Thumb for Steel Design.  John shared some quick reference approximations for mechanical properties of steel sections.  He also identified some rules of thumb for the design of beams, columns, and trusses, and shared some design examples using these rules. 

John offered a quick, simple equation for determining the beam weight based on the moment and selected beam depth. For 50 ksi steel, the slide below shows this quick, useful equation which results in the beam weight per foot based on the moment in kip-feet and the beam depth in inches.

John walked through an example using this rule of thumb to determine the beam weight needed for a 16 inch beam which is 32 feet long with a dead load of 1 kip per foot.

As you can see, the rule of thumb was quite accurate to make a quick determination for the beam size needed for this given loading condition.  John noted that all rules of thumb are approximations and are not always conservative; however, they can be very useful when an on-the-spot intelligent decision is needed.  A rigorous structural analysis should always follow when more time allows.

Using web based tools can save time and increase efficiency during structural analysis, and often these tools are the most up-to-date resources which include changes and updates to the code.  Are you aware of the many online resources available to assist with calculating the shear strength and stiffness of steel deck diaphragms?

In the July 2023 SEU session, Mike Antici, PE, from Vulcraft, and Thomas Sputo, SE, PE, from Sputo and Lammert, LLC, presented, on behalf of the Steel Deck Institute, Diaphragms Are More Than Just Deck and Fasteners.  Tom and Mike explained how traditional shear mechanics are applicable to diaphragms and how the shear stiffness analysis can be used in lieu of designing a diaphragm as rigid or flexible.  They also reviewed capacities and limitations of  joists, deck, and fasteners.  

During the presentation, Tom and Mike mentioned several online tools and analysis resources for diaphragm and fastener checks.  For example, SDI has a Diaphragm Interaction Calculator which produces deck capacities based on the user’s input of various deck profiles, thickness, and spans, as well as different fastener sizes and spacings.  Tom noted the importance of using the correct number of spans in this online tool since the stiffness of the deck is proportional to the number of spans, while the deck strength is inversely proportional to the number of spans.  This free online tool calculates the shear strength and stiffness of the diaphragm as well as the interactive allowable shear strength under combined loads with uplift.

Mike noted that SDI is not the only tool available; many deck and fastener manufacturers have also developed online tools.  Hilti offers its users PROFIS DM Diaphragm which is offered as a free software download.  Nucor offers its customers a Bare Deck Diaphragm tool as well as a Deck-Slab Diaphragm tool which is available free for registered users.  Also, New Millennium Building Systems offers a web based calculator, Deck Tools,  for deck diaphragm capacities.  This online tool allows for roof deck, composite deck and form deck calculations with various fastener patterns.  Simpson Strong-Tie has developed a Steel Deck Diaphragm Calculator as well, which can be used to produce the necessary diaphragm capacity tables for your deck configuration.

Tom and Mike highlighted a number of recent changes within the code which affect the capacity of deck diaphragms, and Mike strongly recommended using these online tools in favor of published manufacturers tables which may be outdated or not include these new code provisions.  Deck diaphragms are a critical component of the lateral force resisting system, and using these free, available resources can validate that all aspects of the diaphragm are capable of providing a continuous load path for your structure.


1 2 3 4 26
SE Job Alert Notifications

SE Job Alert allows us to notify you quickly when new exciting positions become available. Your information will not be sold or shared with other companies.

Sign Me Up