Moment Frames as Stability Systems

Last month, we continued our series of posts on stability systems by taking a look at framed bracing. Today, we’re building on that and bringing the series to a close by taking a look at moment frames and their role in the stability of buildings.

The vast majority of people are already very familiar with this type of bracing, even if they don’t necessarily realise it. They’re used in the vast majority of shed and wardrobe straictures, as shown in the picture at the top of this post.

Moment connections are designed to transfer bendy moments, shear forces and sometimes normal forces. They’re often used in combination with a braced system to form a hybrid stability system.

The connection details are critical when it comes to keeping a building stable if this type of system is adopted. In the UK, it’s usually the structural engineers who specify the element size and subcontractors who design the joint connections. It’s critical that the design information provided by the structural engineer is communicated correctly if this is the case.

Another factor to consider when it comes to moment frames is that they’re almost always less stiff than core walls or framed bracing. This means that if moment frames are going to be adopted then lateral deflection needs to be considered as a key design issue right from the initial design concepts.


We hope our series of posts on stability have been useful and that you’ve learned some insights into some of the systems that our engineers use and the technical considerations they have to bear in mind.

There are many other times when stability needs to be considered such as:

  • During construction
  • Deterioration
  • Structural alterations
  • Changes to how a building is used

We’ll be talking about these topics some more in the future, so be sure to stay tuned for further updates. In the meantime, if you’d like to discuss any project requirements of your own then please feel free to get in touch. We’ll be more than happy to help!

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