Frame Spacing Calculator

Calculator Choose a method, enter inputs, then calculate.

Method

Switching method keeps your shared inputs.

Total length (m)

Distance along which frames are repeated.

Edge offset each end (m)

Clearance from ends to first/last frame.

Minimum spacing (m)

Practical tightest spacing allowed.

Maximum spacing (m)

Practical widest spacing allowed.

Round results to (m)

Controls displayed spacing precision.

Frame count (including ends)

At least 2 frames are required.

Reset

Example data table Sample inputs and outputs.

Method	Total length (m)	Edge offset (m)	Key input	Frames	Spacing (m)
Length + frame count	12.0	0.3	Count = 6	6	2.28
Length + target spacing	18.0	0.5	Target = 2.4 m	8	2.43
Capacity-based	20.0	0.5	q=0.9, L=4, M=4.5	10	2.11

Example values are illustrative and may not match your code requirements.

Formula used

Usable length: L_use = L_total − 2a
Spacing from count: s = L_use / (N − 1)
Count from spacing: N = floor(L_use/s) + 1
Capacity-based (simply supported member):

M_max = wL^2/8 → w_M = 8M_allow/L^2

δ = 5wL^4/(384EI) → w_δ = 384EIδ_allow/(5L^4)

w_allow = min(w_M, w_δ) / SF

s_cap = w_allow/q where w = q·s

Use design-code capacities for M_allow and appropriate deflection limits for your project.

How to use this calculator

Select a method: count-based, target-based, or capacity-based.
Enter total length and edge offsets to define usable length.
Set minimum and maximum practical spacing limits.
Provide the method-specific input fields shown below.
Press Calculate to display spacing, bays, and frame count.
Download CSV or PDF to share the computed layout.

FAQs

1) What does edge offset mean?

Edge offset is the clearance from each end to the first and last frame. It accounts for end details, tolerances, or boundary conditions before repeating equal bays.

2) Why can the spacing change from my target?

The calculator fits an integer number of bays across usable length. It also enforces your minimum and maximum spacing limits, so the final spacing can shift slightly.

3) Which method should I use first?

Use count-based when frame quantity is fixed. Use target-based when you have a preferred module. Use capacity-based when spacing depends on member strength and stiffness.

4) What is the capacity-based method assuming?

It assumes a simply supported member under uniform line load derived from an area load and spacing. It checks bending moment and deflection using classic beam relations.

5) How do I choose the area load value?

Use the combined dead and live loads for the supported surface, including finishes and imposed loads. Match the units to kN/m^2 and apply project-specific load factors separately.

6) Why use a safety factor here?

The safety factor reduces the allowable line load before converting to spacing. This provides conservative spacing, especially when input capacities represent idealized or nominal values.

7) Can this replace structural design checks?

No. It provides fast layout estimates and sanity checks. Always confirm with applicable design standards, connection design, stability checks, and detailed member sizing.

8) What if my frames are not equally spaced?

Use this tool to establish a baseline module, then adjust locally for openings, equipment, or irregular boundaries. Re-check critical members where spacing differs from the baseline.