Progressive Collapse Design
Progressive Collapse Design
(OP)
Hello leds,
I am designing Precast Stairs connected at landing with Bolted Angle, now i need to do Progressive Collapse Design, does it means i need to apply 34kN/m2 pressure as describe in BS8110 : Part 2 :1985 2.6 Robustness?? and then strengthen my connection for the reaction i get from this pressure? and my stairs suppose to be design for this much Pressure?
Best Regards.
I am designing Precast Stairs connected at landing with Bolted Angle, now i need to do Progressive Collapse Design, does it means i need to apply 34kN/m2 pressure as describe in BS8110 : Part 2 :1985 2.6 Robustness?? and then strengthen my connection for the reaction i get from this pressure? and my stairs suppose to be design for this much Pressure?
Best Regards.






RE: Progressive Collapse Design
RE: Progressive Collapse Design
BA
RE: Progressive Collapse Design
RE: Progressive Collapse Design
If it is an emergency escape stair then it is probably required to be checked for robustness.
RE: Progressive Collapse Design
Now tell me by reading above Robustness requirement from BS what does it means?
how and where to apply this 34 load and to check what?
Regards
RE: Progressive Collapse Design
RE: Progressive Collapse Design
RE: Progressive Collapse Design
I don't have, nor are familiar with, BS standards, but page 4 of the above paper has three methods of ensuring that the building has a minimum level of strength for accidental loadings, including: tying and bridging, NOT just designing for a minimum of 34 kPa.
RE: Progressive Collapse Design
Would the failure of your stair lead to the collapse of the rest of the building? I would assume the answer is NO. So it is not Key Element. So the rule does not apply to it.
If it was a Transfer beam supporting the whole building, you answer would probably be YES. Then you would have to apply it!
RE: Progressive Collapse Design
RE: Progressive Collapse Design
RE: Progressive Collapse Design
That is an entirely different concept. Progressive collapse has been described above by MotorCity and others.
What you are talking about is robustness, but of an isolated flexural element, which if removed would have much less effect on the entire structure than, for instance, a column.
RE: Progressive Collapse Design
https://en.wikipedia.org/wiki/Ronan_Point
Structural engineers engaged in the design of buildings should all be aware of the principle involved with the Ronan Point failure.
BA
RE: Progressive Collapse Design
An emergency stair would be covered under the Robustness rules which are covered in part 1 clause 3.1.4. How you provide Robustness for a stair by providing alternate load paths I am not sure. It would depend on the layout. Maybe you should read
Practical Guide to Structural Robustness and Disproportionate Collapse in Buildings - Institution of Structural Engineers - 2010
Manual for the Systemic Risk Assessment of High-Risk Structures Against Disproportionate Collapse - Institution of Structural Engineers - 2013
And No, I do not have copies.
RE: Progressive Collapse Design
“Key Element” is to be considered in building Class 2B and above in case where the requirements of the tying method or the notional removal method have not been satisfied.
RE: Progressive Collapse Design
Regards