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Building. Prof Sarosh Lodi. TOPICS COVERED. Intro. FLEXURAL MEMBERS OF SMRF. General Clear span not less than 4 times effective depth Width/depth ratio not less than 0.3 Width not less than 10 in
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Building Prof Sarosh Lodi
TOPICS COVERED • Intro
FLEXURAL MEMBERS OF SMRF • General • Clear span not less than 4 times effective depth • Width/depth ratio not less than 0.3 • Width not less than 10 in • Width not more than width of supporting member plus distance on each side of supporting member equal to ¾ of the depth of flexural member Cont.
FLEXURAL MEMBERS OF SMRF • Longitudinal Reinforcement • Reinforcement ratio not less than 200/fy • Reinforcement ratio not more than 0.025 • Two bars should be continuous in top and bottom • +ve moment strength at joint face should not be less than ½ of –ve moment strength • +ve or –ve moment strength at any section should not be less than ¼ of strength at joint face • Lap allowed only with hoop or spiral reinforcement • Lap splices are not allowed • within joints • a distance of 2d from joint face
FLEXURAL MEMBERS OF SMRF Longitudinal Reinforcement
FLEXURAL MEMBERS OF SMRF • Transverse Reinforcement • Maximum hoop spacing shall not exceed • d/4 • 8 times dia of smallest longitudinal bar • 24 times dia of hoop bar • 12 in • Examples of hoops are Cont.
COLUMNS FOR SMRF • General • Shortest cross-sectional dimension is 12 in. • Ratio of shortest dimension to perpendicular dimension shall not be less than 0.4
COLUMNS FOR SMRF • Reinforcement • Longitudinal reinforcement ratio not less than 0.01 and not more than 0.06 • Concrete cover for transverse reinforcement shall not exceed 4 in. • Spacing of rings (s) shall not exceed • s=¼ of minimum column dimension • s=6 times dia of longitudinal bar • s=4+[(14-hx)/3] 4”< s <6” • Length of column (L) for above ring spacing shall not be less than • depth of column • 1/6 of clear span • 18 in.
COLUMNS FOR SMRF • Reinforcement • Spacing (S1) for the rest of column length is smaller of • 6 times longitudinal bar dia • 6 in. • Example of rings is
COLUMNS FOR SMRF • Joints • Beam longitudinal reinforcement must be extended to the far face of column and anchored • Column dimension parallel to the beam reinforcement not be less than 20 times bar dia • Transverse reinforcement shall be provided in joint
INTERMEDIATE MOMENT RESISTING FRAME • Beams • +ve moment strength at joint face should not be less than 1/3 of –ve moment strength • +ve or –ve moment strength at any section should not be less than 1/5 of strength at joint face • First hoop provided at 2 in. from face of support • Maximum hoop spacing shall not exceed • d/4 • 8 times dia of smallest longitudinal bar • 24 times dia of hoop bar • 12 in
INTERMEDIATE MOMENT RESISTING FRAME • Columns • Hoops provided at spacing (s) over length (L) from both ends • s should be smallest of • 8 times dia of smallest longitudinal bar • 24 times dia of hoop bar • ½ of smallest dimension of frame member • 12 in • L should be largest of • 1/6 of clear span of column • Minimum dimension of column • 18 in
INTERMEDIATE MOMENT RESISTING FRAME • Columns • Hoops provided at spacing (s) over length (L) from both ends • s should be smallest of • 8 times dia of smallest longitudinal bar • 24 times dia of hoop bar • ½ of smallest dimension of frame member • 12 in • L should be largest of • 1/6 of clear span of column • Minimum dimension of column • 18 in