Simple wind load example (diaphragms)

Tekla Structural Designer
Tekla Structural Designer

Simple wind load example (diaphragms)

Each simple wind load is defined as an area load over a defined width and height.

In the two story example shown below, a 1kN/m2 load is applied over the full 22.5m width and 6m height of the building.

  • The load defaults to being uniform over the full height (as shown above), but levels can be inserted to cater for a stepped loading profile if required. The inserted levels do not have to coincide with actual building levels.

  • The top of the load should align with a rigid diaphragm - if not a validation warning is generated - this is to ensure the loading is distributed as correctly as possible.

  • During decomposition an imaginary 'bounding box' is formed around the building - only the load width within the building profile is considered for decomposition.
  • Load within the bounding box that hits the structure (the blue shaded area above) is decomposed to point loads on rigid diaphragms only - it does not get decomposed to semi-rigid diaphragms.

  • All rigid diaphragms on the top or bottom level or anywhere in-between are considered, with the area load being divided between the levels before it is decomposed. In the example the area load is split between 1st and 2nd floor levels so that a total of 22kN is to be decomposed above and 90kN below.
  • The load is then decomposed to the diaphragms at each level in proportion to the width of each diaphragm. Each load being applied as a nodal load in the direction of the simple wind load at the mid point of the projected load.
  • If there are no suitable diaphragms on the top level, the load is applied at the next level down.

  • Similarly if the 'Ignore diaphragms on lowest level' box is checked on the Simple Wind Loading dialog or there are no suitable diaphragms on the bottom level, the load is applied at the next level up.

Note: If for some reason there are diaphragms at the ground level, then you may decide to check the 'Ignore diaphragms on lowest level' box in order to ensure no load is lost directly to the foundations.
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