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Bracing for Steel Buildings
Dr. Ibrahim Fahdah
Damascus University
https://sites.google.com/site/ifahdah/home/lectures
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Bracing Systems
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Bracing Systems (cont.)
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Bracing System Location
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Connection Classification
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Moment Connection
A
A
Shear Connection
Concentrically Braced Frames
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Concentrically Braced Frames
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Eccentrically Braced Frames
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Bracing sections
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Bracing For Industrial Buildings
• Bracing resists horizontal forces such as wind, crane longitudinal surge, and earthquake. • Every fourth or fifth bay may be braced. But no less than two should be provided. • The bracing can be single diagonal members or cross members. • Single bracing members must be designed to carry loads in tension and compression. • With cross-bracing, only the members in tension are assumed to be effective and those in compression are ignored. • The internal frames resist the transverse wind load by bending in the cantilever columns.
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Roof Bracing Design for Industrial Buildings
PA PA PC PE PC
R R
Ai : Area related to each node Nnode : Number of Nodes nB : Number of bracings WL:Wind on the building face Fr: Fractional drag load on the roof Fw: Fractional drag load on the walls
Nnode =4, nB =2
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AA
Ac AE
Side/Wall Bracing
R WH2 Under tension
Under compression
Load Combinations: For Roof : LC =1.4 WL For Walls : • LC1 =1.4 WL • LC2 =1.2 (WL + WH2)
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Rafter horizontal bracing
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Purlins
Bracing