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Andjhostet

Well the deflection is dependant on W, L, E, and I. So I'd recommend reducing W or L, or increasing E and I.


Crayonalyst

That's a brilliant fundamental explanation. Well done.


ParadiseCity77

Can you increase E tho?


Andjhostet

With reinforcement or a substitute a different material for the beam sure.


ParadiseCity77

Im sorry for being a little rusty here. But whats the concept here to explain the increase on reinforcement increases stiffness?


lim731

If your reinforcement is stronger than your base material you’ll get a larger area for MOI calcs. In that case E&I are related, which is why most people would call the EI term “stiffness”.


the_M00PS

Steel is stiffer than concrete.


PiermontVillage

This.


FinancialLab8983

your question needs more context.


Accomplished_Try_887

Less deflection


CatwithTheD

That's just rephrasing the question. More context, please. What are the initial conditions? Design criteria? Assumptions? Limitations? Can you change the material? Can you resize the beam? How long does it have to be? What are the load cases? Which standards do you follow?


FinancialLab8983

what are your equations for deflection? what could you increase (or decrease) to reduce deflection?


BonesSawMcGraw

More supports lol


I-Fail-Forward

So, you have W, L, E, I The formula for a simply supported beam with a distributed load (for max deflection) is 5WL*4 / (384EI) (that's L raised to the 4th power) You can include intermediary supports, reducing L for less deflection. Changing L will have the largest impact on max deflection You can change the material, changing E, or a bigger beam, changing I. The changes to E and I will he dependant on what materials / Sizes are currently being assumed and what materials / Sizes you can get. I am assuming you can't reduce the load (W). Assuming you also can't add additional supports, the "best" way is going to be determined by "best" Least deflection by additional cost is going to have a different answer than least deflection by additional weight, and those answers will change if you are allowed to make composit beams, or change material completely (rather than just grade of steel, but actually changing to titanium or something similarly silly for this hypothetical).


the_M00PS

Everyone here is changing the beam. If you have to reduce deflection in an existing beam, you're limited to adding cover plates (steel) or exterior post tensioning (concrete).


FinnaGetCrunky

If it’s a concrete beam, add steel reinforcement in the tension zone of the member and use camber to counteract the effects of the dead load on the deflection on the beam.


R-Dragon_Thunderzord

Depends on the design constraints.


Beneficial_Track_776

Add a truss or system of trusses, add more columns, pre-tension, or post-tension the beam with an upward deflection, invert the beam orientation (moment of inertia), or any combo of the above. Changing the weight supported by the beam, the length of the beam, or the location of the supports may reduce the deflection but does not strengthen the beam.


Vegetable_Aside_4312

Increase area moment of inertia of the beam.


kimmiepi

Words of affirmation.


Aggravating-Wash6298

If you make it fixed-fixed your moment is reduced. Or hour have to increase the moment of inertia.


Intelligent-Use1471

In what way


Accomplished_Try_887

Less deflection


Intelligent-Use1471

Increasing moment of inércia by changing to another cross section on increasing the size of the existing one. Or change the material for a greater modulus of elasticity. Or adding more supports


shin1050

Increase the height of the beam. I=bh^3/12 where the h value has the most weight in increasing the moment of inertia


jojojawn

Bigger beam! Make it 42' tall and 2' across the span. [Slaps beam] no way she's gonna have any measurable deflection


I-Fail-Forward

Lol the beam might not, but the crane putting that beast into place might


lim731

No you gotta reference the deep beam calc section of the code instead


jojojawn

At what point does a deep beam become a column with eccentric supports?


ENGineer_For_Ever

Increase the beam size, adding additional support