DIS-TRAN Steel Blog

DIS-TRAN's Top Utility Posts of 2012

Posted by Brooke Barone on Jan 4, 2013 9:50:00 AM

As the new calendar year begins, it’s a good time to look back at all the accomplishments, as well as all the areas of improvement, to ensure that the next 365 days are just as good, if not better, than the previous.

One accomplishment from 2012 would have to be the continuous success of the DIS-TRAN Blog.

For me, the best part about writing each blog is that, as I’m sharing valuable information with others, I’m also learning too. And I couldn’t have done it without the participation and help from all of the employees here who have taught me so much.

So with that said, here’s a recap of some of the 2012 blog articles that seemed to make the biggest impact among our readers.

Top Posts by Page Views:

1. 10 Things You Ought to Know about TimberSIL Distribution Crossarms- Coming in at number one for 2012, this article generated the most interest and moved the conversation about this new “green” product.

2. The Secret to Building Morale by Maintaining Your Plant- This post shows a few simple steps that could change the entire perception of your fabricating facility!.

3. A Cheat Sheet for Electrical Substations- An inside look at how electricity is generated from substations into your home, and the main structures found inside a substation and their functions.

Top Human Interest Posts:

1. Road to Recovery After Hurricane Sandy- Super Storm Sandy left thousands of homes flooded and millions in the dark. Although DIS-TRAN wasn’t physically there, we worked around the clock to assist utilities to get power restored as quickly as possible. Our hearts go out to everyone who encountered Sandy’s devastation.

2. DIS-TRAN Goes Pink- This was an awesome experience and I’m really glad I got to do it with some great people!

3. DIS-TRAN’s Quick Response for Storm Restoration- Real time efforts made by DIS-TRAN and the dedicated employees who make this happen.

Top Informational Posts:

1. Design Practice for Flange Plates versus Slip Joint Connections- Great advice with a little help from our engineering department.

2. How to Use Lean Manufacturing to Increase Production- Lean Manufacturing might be an easy concept to understand, but implementing it takes hard work, persistence and teamwork.

3. Back to Basics in Transmission Structures- For anyone just starting off in this industry, substations and transmissions can get confusing. This article walks through transmission structures and their different configurations at an easy-to-learn pace.

Since September, just within a matter of a few months, our blog has taken off and I’d like to thank all of our subscribers and followers for reading and sharing our posts. If there’s anything you’d like us to write about, share or answer, please leave a comment below and we will do our best to help!

Happy New Year!

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Tags: substations, utilities, transmission, transmission structures, DIS-TRAN, TimberSIL, utility, distribution corssarms, storm restoration, flange plates, electrical substations, joint connections

Design Practice for Flange Plates versus Slip Joint Connections

Posted by Brooke Barone on Oct 11, 2012 10:38:00 AM

Having a good relationship with your vendor will ensure a smooth and confident outcome.

Also, by having seasoned engineers and people who have been in the industry for some time and have experienced things that textbooks cannot prepare one for, more knowledge and expertise will be contributed towards the final product.Dead end tran resized 600

Here are some design practices for using flange plates versus slip joint connections for H-frames, single pole guyed and single pole dead-end structures. There is the concern of the uplift/compression on H-frame poles and the excessive amount of vertical load that can be created for guyed structures, especially guyed dead-end structures, as well as how to apply this for self-supporting dead-end structures.

So, what’s the design practice in this regard?

Most customers leave it up to the fabricator to decide when and where to use slip verses flange joints.  This is typically decided in the quote stage, as this can make or break a job.  If you leave it up to the fabricators, just make sure you know or trust the fabricators that are bidding the project.  There are always new players in the game, so you just need to make sure they’re experienced enough with these type structures to know what they are watching for with these connections. 

In other words, if four out of the five bidders quote structures with flange plates and the low bidder quotes slip joints, then understand why they quoted it that way. 

slip joint resized 600The following are a few suggestions when it comes to these type connections. These are not necessarily found in a design guide book or a required industry standard, just a rule of thumb.

  • Dead-End H-frames/ A-frames: Always use flange plates if the joint is located below the beam connection.  (There have been a few times where the conductor beam was located at 45 ft elevation and the structure was 65 ft tall, so in this case, a slip joint was put above the beam connection.)
  • Transmission H-frames w/ X-Bracing:  Depends on loadings and location of joint.  Most of the time, structures are designed with flange joints because the overlap of the slip joint can vary.  Due to the slip tolerances, it could cause a headache in the field to slip both columns the exact amount for everything to line up.  If slip joints are used, the designer still needs to watch the axial loads.  If they get too high, then they will need to switch over to flange plates. 
  • Guyed Structures:  Always use flange plates if the joint is located below the guy attachment points.  The axial loads tend to get high on these type structures.  Of course, there is always an exception to the rule.  There could be some cases where the axial load remains low for a guyed pole.  In these cases, the loads tend to be small, have some uplift or may have a minimal number of guy wires.  If the customer is requesting slip joints on their guyed poles we watch the axial loads closely. 
  • Switch Poles/Riser Poles/Specialty Poles:  Always use flange plates. (Depending on the arrangement, slip joints on low kV Riser poles can be used.)
  • Single Pole Dead-Ends/Tangents:  Always start out with slip-fit joints.  It’s not often flange plates are used for these type structures, unless the customer requires them.  Normally, the axial load does not get excessive for these type structures.   However, never locate a slip between phases.  If the top shaft gets too long due to phase spacing, switch to flange plates in certain spots.  Sometimes a flange plate is used if there is not enough room to fit a slip on the pole due to lots of brackets/equipment/etc.

In the end, always try to use slip-joints where you can because it’s typically more economical.  As you may have noticed, there is an exception to just about every rule above.  This just means there should always be some flexibility in the project so the design engineer has the ability to make judgment calls as needed.  If the customer works closely with the fabricator on each project then it will run smooth.

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Tags: flange plates, slip joint connections, dead-end h-frame, transmission h-frame, guyed structures, switch pole, riser pole, specialty pole, tangent

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