Pier Spacing and Load Calculator

Calculate pier spacing and the load each pier must support based on beam span, tributary width, dead load, and live load inputs.

Total Beam Span (ft)

Number of Piers (including end supports)

Tributary Width (ft)

Dead Load (psf)

Live Load (psf)

Beam Self-Weight (plf) (optional, per linear foot)

Pier Spacing:

s = L / (n − 1)

Where L = total beam span (ft), n = number of piers.

Total Uniform Load per Linear Foot:

w = (DL + LL) × b + w_beam

Where DL = dead load (psf), LL = live load (psf), b = tributary width (ft), w_beam = beam self-weight (plf).

Interior Pier Load (ASD):

P_interior = w × s

End Pier Load (ASD):

P_end = w × (s / 2)

LRFD Factored Load Combination (ASCE 7-22 §2.3.1):

w_u = 1.2 × DL × b + 1.6 × LL × b + 1.2 × w_beam

Tributary Area per Interior Pier:

A_trib = s × b

Piers are assumed to be uniformly spaced along the beam span.
Loads are assumed uniformly distributed over the tributary area.
End piers carry half the tributary load of interior piers (simple beam assumption).
No lateral or seismic loads are considered in this calculator.
LRFD load combination used: 1.2D + 1.6L per ASCE 7-22 §2.3.1.
Beam self-weight is applied as a uniform line load (plf) along the full span.
This calculator does not account for beam continuity effects; for continuous beams, reactions at interior supports may differ.
References: ASCE 7-22 Minimum Design Loads for Buildings and Other Structures; NDS 2018 National Design Specification for Wood Construction; IBC 2021.

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