Frame column stiffness

Frame column stiffness in direction j (j=x, y):

Frames could comprise either columns only, called “frame systems” or columns and walls called “dual systems”. These two types of frame systems will be considered in the following paragraphs.

The structural frame model without rigid bodies but fully stiffened

In project <B_5151a> of the related software, the cross-section of all columns is 400/400 and their height 3.0 m. The cross-section of the flanged beams is 300/500/1300/150 and their span 6.0 m. The seismic horizontal force is equal to 50 kN.

Elastic line, δ=0.695 mm

Shear force diagrams

Bending moment diagrams

The structural frame model fully stiffened, project <B_5151b>

Project <B_5151b> derives from project <B_5151a> by adding foundation beams with cross-section 300/800/1500/400 at level -0.80 m

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Elastic line, δ=1.480 mm

Shear force diagrams

Bending moment diagrams

One-storey dual type structure comprising two columns and a wall (project <B_5152a>)

In project <B_5152a> of the related software, the structure comprises two end columns and a wall in the middle with cross-sections 400/400 and 2000/300 respectively. Their height is 3.0 m. The cross-section of the flanged beams is 300/500/1300/150 and their span is 6.0 m. The horizontal seismic force is50 kN.

Elastic line, δ=0.059 mm

Shear force diagrams

Bending moment diagram

The structural frame with the actual stiffness in project <B_5152b>

Project <B_5152b> derives from project <B_5152a> by adding at level -0.80 m flanged foundation beams with cross-section 300/800/1500/400.

Elastic line, δ=0.382 mm

Shear force diagram

Bending moment diagram