Portal frames quiz

Please answer the following 10 multiple choice questions, then click 'submit' to check the result. The pass mark for a CPD certificate is 8 out of 10, and you may retake the quiz as many times as you wish, but the questions will vary! Please note that one, two, three or all of the possible answers presented for each question may be right, and to gain a mark for that question all correct answers must be identified.

Good luck

Portal frames

When should the junction of the inside face of the column and the underside of the haunch be restrained?

Only in the gravity combination of actions
Always
If there is not a side rail and compression stiffener at that level
If a side rail can be provided at that level

How is a moment-resisting base commonly detailed for the fire condition, if necessary?

With a thicker base plate
With more holding down bolts
Set into a pocket cast in the base
Provided with stiffeners

What best describes a portal frame structure?

Frames of simple construction
3-d continuous structures
Continuous frames in-plane, braced in the longitudinal direction
Continuous frames, braced in-plane

How can second-order effects in portal frames be allowed for?

By using a second-order analysis
By amplifying the lateral loads
By using S355 steel
By down-rating member resistance by 10%

Which of the following combinations of actions should be verified for portal frames?

Permanent + Wind
Permanent + Snow
Permanent + Snow + Wind
Permanent + Wind + Imposed

When should a portal frame be used for the gable frame?

When future extension is anticipated
For aesthetic reasons
To save weight
So that gable columns are not required

Which of the following situations should be verified as an accidental combination of actions?

Snow removed from one roof slope
Snow accumulating behind a parapet
Snow on the roof if the altitude is above 150 m
Snow accumulating in a valley

What value of base stiffness is recommended when modelling nominally pinned bases?

Zero - it's a pinned base
Zero - at ULS
10% of the column stiffness when calculating frame stability
20% of the column stiffness when considering SLS

What steps are effective in reducing the calculated deflections at SLS?

Modelling the stiffness of nominally pinned bases
Using higher strength steels
Using members with a higher inertia
Adding restraints

When might a Morris stiffener be required in a haunch connection?

When the vertical shear exceeds the resistance of the rafter web
When the panel shear exceeds the resistance of the column web
Whenever a compression stiffener is provided
To provide a fixing point for the vertical bracing and the eaves member