Forces in a Howe truss (SE130)

Forces in a Howe truss (SE130)

measurement of bar forces on a single plane truss, Howe type



  • As light-weight structures offering a high degree of rigidity, trusses are employed in the construction of halls, bridges, cranes, pylons and masts.
  • Trusses are bar structures in which the bars are subjected to compression or tension loading, but not to bending.
  • The SE 130setup provides experiments on single plane trusses with a high degree of measuring accuracy and computerised result readout based on software.
  • The ready assembled truss is mounted horizontally on a frame.
  • The influence of the dead weight is minimized by horizontal experimental setup.
  • The bars are joined by a “hinged” connection, using node disks.
  • Consequently, our truss can be considered as an ideal truss.
  • The external force is generated with the aid of a threaded spindle.
  • The force can be applied in various directions and at various points.
  • The forces occurring on the truss bars are recorded by strain gauge measurement.
  • All measuring points are housed together in a connection box.
  • From there, they are connected to the measuring amplifier FL 152.
  • The software is used to manage the measuring data and provide graphical representation of the bar forces.
  • The software features a comprehensive help function.
  • An additional truss is available to extend the scope of the experiment: SE 130.01, Warren type.

Technical details:


  1. investigation of bar forces in a single plane, statically determinate truss
  2. ready assembled Howe truss
  3. frame for horizontal experimental setup
  4. influence of dead weight minimized by horizontal experimental setup
  5. any straight and inclined load cases possible
  6. fine adjustment of load force
  7. low-friction knife-edge bearing
  8. 2 supports for vertical forces, 1 support for horizontal forces
  9. pre-balanced strain gauge connection box with connection to measuring amplifier FL 152
  10. measuring amplifier FL 152 required
  11. GUNT-software in FL 152 to evaluate measured values graphically

Technical Data:

Truss: Howe type

  • bar cross-section: 10x3mm, stainless steel
  • bar lengths: 115,5, 200, 231mm
  • external loading: max. 500N
  • bars: 13, of which 7 with measuring points

Load application device with force gauge

  • tensile force: max. 600N
  • stroke: 30mm

Node disks: 8

Angle between bars: 30°, 45°

Dimensions & Weight:

  • L x W x H: 1220x620x250mm (frame)
  • L x W x H: 850x265x15mm (Howe truss)
  • Weight: approx. 43kg

Learning Objectives/Experiments:

  • measurement of the bar forces in a single plane truss, Howe type
  • dependency of bar forces on the external force
  • magnitude, direction, point of application
  • comparison of measuring results with mathematical and graphical methods
  • method of joints
  • Ritter’s method of sections
  • Cremona diagram
  • basic principle: measurement of forces using strain gauge measurement

Scope of delivery:

  • 1 frame
  • 1 Howe truss
  • 1 load application device
  • 1 strain gauge connection box
  • 1 ribbon cable
  • 1 set of instructional material


  • measurement of bar forces by strain gauge measurement
  • external load may be applied at different angles


·         Required: FL 152 multi-channel measuring amplifier

·         Optional:

–      WP 300.09 Laboratory trolley

–      SE 130.01 Truss beam: Warren girder


Due to the continuous development of our products, the goods supplied may vary in detail to that illustrated on this Website.