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Seismic Design of Inclined beams(Rafters) steel portal frames

Seismic Design of Inclined beams(Rafters) steel portal frames

Seismic Design of Inclined beams(Rafters) steel portal frames

Hi Everyone,
I intend to design a large span roofing steel inclined beams portal frames. The structure is located in high seismic zone where codes (ASCE7 & AISC341) normally suggests special moment resisting frames. I have some queries regarding design of this structure listed below.

1. Does these inclined beams (rafters) steel portal frame system is acceptable in high seismic zones?, where highly ductile behaviour is expected from structure (as per AISC 341-16). Kindly give any code reference if any?

2. If this moment resisting frame is acceptable in high seismic zones then Is there any limit on angle of inclination for this type of frame to be accepted efficient enough to resist lateral seismic forces? Because as the angle of inclination of rafter increases (becomes steep) its resitance to lateral loads decreases. Any code reference in this regard?

3. If this moment resisting frame is acceptable in high seismic zones and can be detailed as SMF, kindly guide what value of Lh(Distance between plastic hinges) shall be taken to calculate Additional shear at column beam connection due to probable moment (as per AISC 358-16)? In other words what will be location of plastic hinges? i.e whether any plastic hinge be formed near the moment Apex joint of Rafters?

4. Is there any special requirement for seismic design for multibay inclined beams/rafters portal frames.?

Hope I elaborated my question well. All your responses shall highly be regarded. Further kindly elaborate your opinions with code references or any helping material which I can easily refer.

Thanks and Regards

RE: Seismic Design of Inclined beams(Rafters) steel portal frames

I preferred to suggest you to read the worked example 9.1 INDUSTRIAL HIGH-CLEARANCE BUILDING at the the following link .I hope you will find answers to your queries .


RE: Seismic Design of Inclined beams(Rafters) steel portal frames

Thank you so much @ HTURKAK that is really helpful. Further the referred document too contains much more helping material.

Thanks again for your kind response.

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