A single entered point load is placed along an ideal simply supported span. Static moment balance gives the two vertical reactions.
Wooden Road Bridge Truss Interactive Calculator
Enter one point load, its span position and panel count. Outputs are support statics only—not truss member forces, timber capacity or bridge safety.
Ideal left support reaction
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Ideal right support reaction
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Larger ideal reaction
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Fractional panel coordinate
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Equation Used
RL=P(1-x); RR=Px; maximum=max(RL,RR); panel=xn.
Load position is a fraction of span. Self-weight, distributed loads, dynamics and member geometry are omitted.
- Span is simply supported.
- One vertical point load acts at entered position.
- Reactions are vertical and static.
- Panel location may be fractional.
- Member forces, self-weight, impact, timber strength, connections and safety are omitted.
Point Load on a Simply Supported Span
The visual places one load on an ideal span and closes vertical-force balance.
What This Represents
Two-support statics, not a truss analysis.
Support-reaction Equations
RL=P(1-x)
RR=Px
RL+RR=P
RR=Px
RL+RR=P
Worked Scenario
A centered 10-ton point load gives 5 tons at each ideal support.
Assumptions and Limits
No member forces, distributed loads, impact, timber strength or safety is calculated.
Frequently Asked Questions
Is the truck a point load?
Yes.
Is bridge weight included?
No.
Are truss forces solved?
No.
Can panel location be fractional?
Yes.
Are dynamic effects included?
No.
Can this rate a bridge?
No.
References
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