Features
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. 
 
Tesca Forces in a Howe Truss setup 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: Warren type.  

Specifications
Investigation of bar forces in a single plane, statically determinate truss  
Ready assembled Howe truss  
Frame for horizontal experimental setup  
Influence of dead weight minimized by horizontal experimental setup  
Any straight and inclined load cases possible  
Fine adjustment of load force  
Low-friction knife-edge bearing  
2 supports for vertical forces, 1 support for horizontal forces  
Pre-balanced strain gauge connection box with connection to measuring amplifier FL 152 
Measuring amplifier FL 152 required  
Tesca-software optional to evaluate measured values graphically  

Technical Specifications
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°  

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