Lateral Propping for Precast Slender Beams

[amaidj]

HI,
guys i have Precast beams of 1.8 meter deep and 400mm width so basically very slender beams, now do i need to prop them Laterally? like we do precast walls?

Regards,

 

[WARose]

ACI 318 requires lateral support for flexural members if the span (or spacing of lateral bracing) exceeds 50 times the width of the "the least width of compression flange or face". So I don't know what your span is......but you may not need it.

If it comes right down to it: you can calculate the LTB/Buckling value raw...... and (with a healthy safety factor) check it yourself.

 

[Lomarandil]

Additionally, if the beams will be subject to any lateral load (wind, seismic) prior to the deck being cast (or other permanent lateral diaphragm installation), you may need props to handle that global stability.

PCI recently published a guide for precast concrete stability -- formalizing the research by Mast years ago that has been used successfully for the past decades. I recommend it as a good introduction.

 

[amaidj]

@Warose, my span is 6 meters but depth is around 1.88 meters and width is 300mm now my concern is considering depth of beam do i need lateral propping?

Regards

 

[Lomarandil]

amaidj -- those proportions are reasonable, but don't just take our word for it -- either dig into the references noted or perform a rational analysis (or hire someone to do one for you) and prove it to yourself.

In some circumstances, you can get away without lateral propping. In some circumstances, you might need it, even with that relatively short span.

 

[WARose]

[blue](amaidj)[/blue]

@Warose, my span is 6 meters but depth is around 1.88 meters and width is 300mm now my concern is considering depth of beam do i need lateral propping?

I wouldn't think that would be an issue at all.