Stack Conical Transition Analysis

Cone Stresses

Analysis of a conical transition isn’t as simply as looking at just the section properties along the cone. Cone-cylinder junctions are areas of high discontinuity stresses. They have unbalanced radial loads from the axial and bending loads it sees, as well as localized bending stresses due to the angle change. The standards that most appropriately…

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Anchor Bolt Design

Photo of stack showing Stack Anchor Bolts

MecaStack performs anchor bolt designs for tensile and shear loads, using some common codes.  This hasn’t always been true, starting in v5534 some new standards were added and this article explains the technical details associated with these new options.  New design standards were added that the user can select and the stack was checked for the…

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Too Close for Comfort

Closely Spaced Steel Stacks

How close can you space stacks?  It’s a common question, and one that doesn’t have a simple answer.  There are several factors that should be considered, and I’m going to go over those factors in this article. The Theory: When two cylinders are closely spaced and the wind is approximately acting along a line between…

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Navigating the Output Like a Boss

navigation GPS

There are many useful features within the output window that can save the designer time and energy.  The more you create for your structure, the more information you will need to record. The output form will organize and display your measurements, allowing you to review and print it. Please check out our other videos to…

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Fastest-Mile Wind Speed

Usain Bolt

Many times we have the difficult task of analyzing a structure that was designed long ago.  In such cases, you may find that the wind speed  used may appear significantly lower than the wind speed you would expect for that location using today’s standards.  In these situations, it’s always important to understand the definition of…

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Climbing the Ladder

Caged Ladder

MecaStack allows the user to enter ladders and platforms on their stack. These are considered an appurtenance, and not adding any structural stiffness to the stack. MecaStack does consider the wind area and weight added by these ladders and platforms, which can be significant on a stack. Ladder Weight and Wind Area: MecaStack considers the…

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Piggy-Back Stacks

Space Shuttle Piggy Back on a 747 Jet.

We often get the question of how to model a Tandem or Piggy back stack in MecaStack. One can be handled by the software and the other cannot. Piggy-Back Stacks: A Piggy-Back stack is one where one or more stack is supported by another stack. Usually the biggest stack is the main support, and then you…

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Ultimate Guide to Material Properties

Stress Strain Curve

MecaStack has a built in database for stack material properties, which are intended to help the designer. There are some common questions and problems that we see when it comes to the use of the stack material properties. Material Properties are NOT Automatically Updated: The first step when adding a material to your MecaStack model is to go…

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Life is a Breach

Breach Tube

Life is a Breach Jan 10, 2020 Updated April 16, 2020: The method of breach analysis discussed in this article is referred to as the “Section Property” method in MecaStack.  As of v5506 there is now a method available called the “Troitsky” method, and an article discussing that method is in another article, click here to…

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Add Some Guy Wires

Guyed Flare

Add Some Guy Wires Dec 13, 2019 When and why should I use guy wires on a stack? When a stack has a vortex shedding problem there can be many factors that determine which solutions are the best.  Guy wires aren’t always the most conventional solution, but its always an option to consider. How do…

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Slow Down

Slow Down

Slow Down Nov 8, 2019 I’ll bet “Slow Down” isn’t an expression you hear much in your business.  I dream of a day when a customer tells me, “Slow down, we really don’t care when you finish your design.”  I can’t get you more time on your deadline, but I can tell you one instance…

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I Feel the Need, the Need for Speed

Top Gun F-14 Tomcat Jet

I Feel the Need, the Need for Speed Oct 18, 2019 In my humble opinion, the Movie Top Gun is one of the best movies of all time.   One of the best parts is when Tom Cruise says “I feel the need, the need for speed”.  It’s not just a great line, it also applies…

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Welcome to our Damping Pad

Damping Pad for Steel Stack

Welcome to our Damping Pad Sep 19, 2019 When a vortex shedding problem exists on a stack, sometimes the most economical option is a damping pad. What is a damping pad? A damping pad is a preformed laminated fabric pad of a manufactured material composed of layers of tightly twisted, closely woven lightweight material. Each…

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How to Determine Damping

Viscous Damper

How to Determine Damping Jul 26, 2019 We can all grasp the physical attributes of a stack such as the height, weight, diameters, etc.; however, what is the stack’s structural damping?  Does MecaStack estimate the damping of the stack?  Is there any harm in just arbitrarily changing the damping value? Damping Basics: To answer this question we…

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Getting Twisted about Helical Strakes

Wind Flow Graphic Comparison of Helical Strakes on Stack

Getting Twisted about Helical Strakes Jun 25, 2019 If you have a vortex shedding problem on a stack, then in some cases helical strakes are your best option; however, there are other cases where helical strakes are not the best option. When not to use Helical Strakes? If there is another stack (or tall structure) that is…

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Take Vortex Shedding Seriously

Transverse Periodic Forces at Frequency Fvortex

Take Vortex Shedding Seriously May 20, 2019 When I was a new Engineer working for an equipment manufacturer, I can say that I didn’t have a healthy appreciation for wind Induced vibration (vortex shedding).  I worked for an equipment manufacturer who won and lost jobs based upon our cost, and considering vortex shedding increased our…

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MecaStack Default File

Default of USA dollar currency concept photo

MecaStack Default File by Chris Rosencutter | May 14, 2019 | Stack There is a feature in MecaStack that is seldom used, but can be very helpful. It’s a feature under the File Menu called “Save Current File as Default”. What does it do? When this feature is is selected, it takes the current file and sets it up as the…

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Tune up your next Stack

Example of Tuned Mass Damper

Tune up your next Stack Apr 5, 2019 One of the most common problems encountered on a cylindrical stack is Wind Induced vibration due to Vortex Shedding. If you have never visually observed vortex shedding, watch this brief video and prepare to be amazed. There are a couple of options to address this problem, and this newsletter…

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