Question

NOTE: This question refers to STEEL DESIGN (LRFD). You may use the AISC Steel Construction Manual if you need to (you can look in google for the manual). Please answer all parts.

A) Notional loads are applied as 0.002 times the gravity load at each floor. What is the basis for this value? Please try to be as detailed as possible.

B) For a beam braced against lateral-torsional buckling, a brace point must be restrained for both twist and lateral movement of the compression flange. (True or False)

Answer 1

フ Ni a.002 Yi. 002 500
B.) It's TRUE that for a beam braced against lateral-torsional buckling, a brace point must be restrained for both twist and lateral movement of the compression flange.

Because, When the compression flange is not continuously braced, lateral-torsional buckling can reduce the available bending moment below the value of Mp/Ω assumed earlier for laterally braced beams. How much this stress is reduced depends on whether the beam buckles before or after the cross section begins to yield and how bending stressesvary over the beam’s unbraced length.