STATICPH
Structural
- Sep 15, 2010
- 16
A client of mine have totally messed up a design of mine.
Description of designed structure:
8 x 6 metre corrugated iron roof fitted in a LAM beam frame
LAM beams are 365x102 Grade 8 CAPE LAM
Rafters in frame are 288x70 Grade 5 SAP and span in the 6m length with 75x50 G5 SAP purlins transverse
What they installed:
Frame as per design above with an additional central beam member of size 365x65 GRADE 8 CAPE LAM (Span 7.4 metre supported on brick work), with rafters 150x52 G5 SAP. The 150 rafters brace the beam well and design is O’k’.
I have checked the design and the “new” LAM beam and it deflect by +56mm and -42mm. I am going to fix it by adding a “timber flange” on the bottom cord of the beam. (the Limit is 41 mm,)
Bending strength are only fine if I assume that the beam is fully braced on its length. But I find that the truss hanger they installed are weak and it could compromise the bracing stiffness.
Any comments
Description of designed structure:
8 x 6 metre corrugated iron roof fitted in a LAM beam frame
LAM beams are 365x102 Grade 8 CAPE LAM
Rafters in frame are 288x70 Grade 5 SAP and span in the 6m length with 75x50 G5 SAP purlins transverse
What they installed:
Frame as per design above with an additional central beam member of size 365x65 GRADE 8 CAPE LAM (Span 7.4 metre supported on brick work), with rafters 150x52 G5 SAP. The 150 rafters brace the beam well and design is O’k’.
I have checked the design and the “new” LAM beam and it deflect by +56mm and -42mm. I am going to fix it by adding a “timber flange” on the bottom cord of the beam. (the Limit is 41 mm,)
Bending strength are only fine if I assume that the beam is fully braced on its length. But I find that the truss hanger they installed are weak and it could compromise the bracing stiffness.
Any comments
