Category Archives: Our Friends & Associates

SpaceGass Training Videos and Tutorials

I found this series of SpaceGass training videos on YouTube and thought they were worth sharing.

The videos are getting a bit old now (2010) but that’s the version we use at Cornell Engineers – and I suspect this version is still in use in quite a few small structural engineering consultancies.

SpaceGass is an awesome 3d structural engineering analysis program. Buy it at the SpaceGass website. Continue reading SpaceGass Training Videos and Tutorials

Follow the Load Path Luke

Good morning to all the structural engineers in the world. Here’s a message for you:

Don’t forget to Follow the Load Path!

What is a Load Path?

A load path is the chain of structural elements that a load follows to get to the foundations which is normally where the assessment of load path stops.

A Sample Load Path

For example the load path of a person standing onthe upstairs floor of a double storey house is something like this:

  • Person stands on the floor
  • The flooring spans between joists
  • The flooring bears onto the joists at each joist. The load is the sum of the weight of the  person and the weight of the flooring. If the person stands mid-span between the joists a structural engineering can determine the bending moments in the flooring and the load into each joist.
  • The loaded joists span between bearers.
  • The loaded joists are connected to the bearers in a way that transfer their own self weight and the weight of the person.
  • The bearers span between posts.
  • The bearers are connected to the posts to transfer the loads and their own weight.
  • The posts act as columns and are streng enough to resist buckling under the combined axial load and induced moment by the eccentricity of the load.
  • The posts sit onto the foundation  slab or pad footing and the load  is transferred through the base plate.
  • The pad footing spreads the load into the foundation material. The depth and dimensions of the pad footing are sized appropriately to not overload the soil.
  • The pad footing reinforcement is designed to transfer the load into the coreect size of pad footing.

Each item of load takes load and transfers it to the next structural element.

Why Follow the Load Path

This is the work of a structural engineer.

When the load path is determined for each structural element being loaded and each of the structural elements is designed to take the load and pass it on through the chain – that’swhen the structure has been appropriately designed.

Why do Buildings Crack?

The structural enegineer does not have to get it right – well they do but let me explain.

When a structural engineer gets the design of the load path wrong, to a certain extent the structure will still work – it just won’t work the way the structural engineer intended.

So the load will travel through a stryuctural element, the element will deflect and move until the laod is transferred and then the new load path will be established.

That movement. That deflection. That’s the unintended consequence of the load path not being designed appropriately.

Of course, if the structural engineer gets it really wrong, that movement works towards collapse.

Advice to Structural Engineers

Follow the load path Luke. Design the structure properly and check that it will act the way you intend. Design each element in the load path for the load in, the span and the load out.

Structures do not get designed by computers. They get designed by smart structural engineers who follow the load path.

Douglas the Stair Master

I met Douglas Campbell on site at Annerley, Brisbane today. Douglas was building a set of hardwood timber stairs for a mutual client of ours.

The timber Douglas is using is Kwila, also known as Merbau. Check out Timber.net’s database for Kwila.

Anyway, Douglas is available to build hardwood timber stairs in Brisbane. Phone 0448 427 167 or email douglascampbell48@yahoo.com.au.

Nice to meet you Douglas.