December 30, 2013


How Do I Model a Tapered Pipe?


Tapered members are common for metal buildings and pole-type structures. For tapered wide flange members RISA provides a quick way to generate a tapered section that can then be checked per the provisions of AISC Design Guide 25 on tapered wide flanges.

There is no automated procedure for tapered pipes. However, there is still a straightforward procedure. Let’s create a 20’ tall tapered pipe pole that tapers from 20” at the base to 11” at the top and assume a uniform ½” thickness. I will use 2’ uniform sections of pipe and splice them together to create the tapered section.

Taperedpipe1

Shown above is the first 2’ section. From here each individual 2' section is input using a diameter 1" smaller than the previous section. Continue drawing these 2’ segments until the top of my pole (20') is reached. The number and length of segments is up to you, but tighter spaced segments will produce a smoother taper and generally better results. Be sure to draw each segment as fully fixed to the previous.

Taperedpipe2

Also, make sure that the unbraced length of each segment is set to the proper value. Generally this value would be the full length of the member.

Taperedpipe3

Tags: RISA-3D Modeling

You may also be interested in

Nov 8, 2018 | Tips & Tricks
Mat Slab Overturning and Sliding Safety Factors

RISAFoundation v11.0 includes two new tabs in the Safety Factors resul...
Read More

Aug 21, 2019 | Tips & Tricks
RISA-3D v18 Sneak Peek Videos

The new release of RISA-3D is right around the corner! Check out our t...
Read More

Jul 12, 2019 | Tips & Tricks
Implementing Realistic Behavior for T/C Members in RISA-3D

Tension or Compression (T/C) Only members are commonly used in steel b...
Read More

Jun 20, 2019 | Tips & Tricks
Understanding Wall Panel Forces with Rigid Diaphragms

Rigid diaphragms represent a plane of very high rigidity and distribut...
Read More