Truss Point Load and Span Capacity
UDL capacity from manufacturer curves; reactions, equivalent-UDL safety factor, pass/fail.
Example
You enter
- Truss model 16in_box
- Span (ft) 40
- Point loads position (ft) 10, weight (lb) 200; position (ft) 20, weight (lb) 400; position (ft) 30, weight (lb) 200
You get
- UDL capacity at this span 77
- Total uniform capacity (lb) 3080
- Total point load (lb) 800
- Safety factor 1.925
- Pass / fail PASS
Checked against published worked examples from: Tomcat USA.
Details, formula, and sources
Formula or tableEquivalent UDL (lb/ft) interpolated from manufacturer span-vs-load curves; equivalent-UDL safety factor; reactions A / B from simple-beam math; 2× point-load rule of thumb.
Source and editionManufacturer truss span-vs-load tables (Tomcat, Total Structures, Tyler GT, Global Truss) by name; ANSI E1.21 (Entertainment Technology - Temporary Ground-Supported Structures) by name.
Free accessManufacturer charts free at each manufacturer site. ANSI E1 standards licensed; some E1 documents (E1.21, E1.4-2014) free at tsp.esta.org.
What governsEstimate. Head rigger and manufacturer working-load-limit charts govern. Inspect every piece of hardware before the show.
API field namestruss_model, span_ft, point_loads, udl_max_lb_per_ft, total_uniform_capacity_lb, total_point_load_lb, safety_factor, pass
- Curve table manufacturer-attributed per row; quarterly recheckmanufacturer technical bulletins
- Point-load to equivalent-UDL factor 2× rule of thumb for centered point loadsmanufacturer typical