General Flashcards
What is the hierarchy of stiffnesses in stability calculations?
Axial
Bending
Torsional
Why are end fixings important for long beams?
Bolt slippage can cause large deflection in longer beams
How are wind loads applied to a structural model?
As points on beam-column connections which represent the area around that point
What size of bolts are required for moment connections?
8.8
Why is there no k in PC1 & PC2 for prestressed concrete?
There are no losses at transfer
Which inequalities bound the profile of bowed reinforcement bars?
PC1 & PC4
What is the stiffness at the upper end of a column which is attached to two beams either side (bl & br) and a column above (cu)?
Ku = (Kc + Kcu)/(Kc + Kcu + Kbl + Kbr)
How does a plate girder bear loads?
Top flange takes compression moment
Web takes shear
Bottom flange takes tension moment
What are the limits of depth to web thickness ratio for plate girders?
100-250
How is a prestressed concrete beam analysed and what does this mean?
Serviceability limit state so no factors are used
What is the minimum limit for steel stress at the bottom of a composite beam?
165N/mm2
What must you remember when finding the stress in the top of the concrete?
Convert values back from steel to concrete
What must you do for a composite beam question?
Draw a diagram of all forces and lever arms
What is the limit for c in a plate girder?
Epsilon x flange thickness where epsilon is in the Eurocodes
What is depth d of a plate girder?
Height y - flange thickness
What must always be done for point loads on a plate girder?
Stiffeners are positioned under them
What is a in plate girder stiffener calculations?
Spacing between stiffeners
What is the approximation for the moment at the end and centre of a rigid portal beam?
M= wL2/16
What diagrams must be drawn in a rigid steel portal frame question?
A full dimensioned frame and a section of the bays with half of the columns above and below
If there is a wind load of 28kN per floor on a 6 storey building (including ground floor and roof), what is the total?
0 x 14 + 4 x 28 + 1 x 14 = 126kN
What is the short term concrete conversion factor for a composite section?
E of steel / E of concrete
What is the long-term concrete conversion factor of a composite section?
2 * E of steel / E of concrete
What must be found to compute the elastic stresses for short term and long term in a composite section?
The second moment of Area (I) for both short and long term
What moment is used to calculate the short-term elastic stresses?
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