QUICK ESTIMATE FOR SWAY DEFLECTION IN A MULTISTOREY STEEL MOMENT FRAME
QUICK ESTIMATE FOR SWAY DEFLECTION IN A MULTISTOREY STEEL MOMENT FRAME
(OP)
I'm preparing for the IStructE Chartered member examination in January. I'm looking for a very "quick and dirty" way of estimating the sway deflection under wind load in a steel building moment frame. Typical building bay width is 6 to 8 m and storey height 3 to 4 m. Could be any number of bays or storeys.
Been googling this all day but no success. Needs to be a 2 minute back of envelope calculation.
Thanks.
Been googling this all day but no success. Needs to be a 2 minute back of envelope calculation.
Thanks.
RE: QUICK ESTIMATE FOR SWAY DEFLECTION IN A MULTISTOREY STEEL MOMENT FRAME
RE: QUICK ESTIMATE FOR SWAY DEFLECTION IN A MULTISTOREY STEEL MOMENT FRAME
Assume joints do not rotate. Assume point of inflection is always at mid-height of story. Then, the deflection of each half story height is equal to the deflection of a fixed end cantilever: VL^3/3EI, where V is the story shear and I is the summation of I for the story.
DaveAtkins
RE: QUICK ESTIMATE FOR SWAY DEFLECTION IN A MULTISTOREY STEEL MOMENT FRAME
RE: QUICK ESTIMATE FOR SWAY DEFLECTION IN A MULTISTOREY STEEL MOMENT FRAME
Assuming beams and columns of equal stiffness rotation at beam-column joints will magnify Column displacements By a factor of 2.25 approx. using this I will develop a table of factors to amplify column sway displacement for various ratios of beam and column stiffness.