Steel Beam Camber from Dead-Load Deflection
Camber = a fraction (75-80%) of the dead-load deflection 5 w L^4 / (384 E I), rounded to 1/4 in. 1.0 kip/ft, 40 ft.
Example
You enter
- Uniform dead load (kip/ft) 1
- Simple span (ft) 40
- Moment of inertia I (in⁴) 2100
- Modulus E (ksi) 29000
- Camber fraction of DL deflection 0.8
You get
- Dead-load deflection 0.95 in
- Specified camber 0.75 in
Details, formula, and sources
I 2100 -> 0.95 in deflection, 3/4 in camber; a stiff 20 ft beam deflecting 0.05 in is left flat (below the ~3/4 in practical minimum). The structural drawings govern.
delta = 5 w L^4 / (384 E I); camber = round(fraction x delta to nearest 1/4 in).
Steel beam camber from the dead-load deflection, standard AISC / fabrication practice, by name.
The simple-span deflection and the fractional-camber rounding are standard published structural results.
Estimate. AHJ and licensed professional govern.
Field names used by the API: w_kip_ft, span_ft, moi_in4, e_ksi, fraction, defl_in, camber_in
- Deflection delta = 5 w L^4 / (384 E I) simple spanbeam theory
- Camber fraction (75-80%) of delta, rounded to nearest 1/4 inAISC / fabrication practice
- Practical minimum not cambered below about 3/4 infabrication practice