10 Flashcards
What is lateral torsion buckling
Where a linear structural member displaces laterally. The member must be a compression
Which changes from an axial load to A bending moment which stresses the member more
And in beams is called lateral
Preventing L. T.b
,ensuring members are straight, plumb and aligned using knee bracing when it occurs at the bottom (buckling) of the beam OR purlins in plane of the Or steel studs in concrete
Flange buckling summary
They occur when the flange is in compression. Often when compression is at its highest at midspan for the top and never supports for the bottom web stiffeners can be used to prevent buckling
What are holding down bolts
A structural system which ties A steel structure to A foundation. Can ALS be used in machinery to tie it down
How do hd bolts work
They work in tension and become chemically bonded to concrete if a base plate is attached it forms a 60° cone which increases the strength of the bolt. The came is dependent on the area of concrete around it
When is come resistance reduced
They are reduced in stub columns which increases their risk of failure
Thus to prevent their tension force should be minimized
Strongest type of anchor and mechanical methods of increasing effective length
Hd bolt with base plate and hook and bend hd bolt
Guidelines to design of base plates
1 the thickness of the base plate is 20 mm to 30 mm ditto hd bolts and 6 m m to 8mm for column welds
2. Foundation should be considered pinned
3. Failure are due to hd bolts
Location of base plates
Usually on stub concrete columns 300mm high to prevent the column standing in water
What do haunches do
Used in moment connections to increase the moment capacity of locations at highest stress
