HST38 Deflections of Trusses

A set of eighteen truss members with lengths based on the 3:4:5 triangle enables at least three different three bay cantilever trusses to be built by creating true pin joints. Two 3:4:5 triangles and a 20.5° top member inclination truss can be created.

Two springings are supplied at one end of the truss and the fix to one of the vertical sides of the HST1 Universal Frame and Stand (sold separately). The truss joint deflections are measured using a movable dial gauge mounted on a sub-frame attached to each springing. Having common mounts for the truss and dial gauge sub-frame ensures the deflections are truly relative to the truss springings.

Each joint deflection is measured in turn and using Castiglianos theorem and the unit load method the actual truss deflections can be compared against theoretical values.

A set of calibrated weights and hanger is supplied for loading the truss. A comprehensive instruction manual and 2 year warranty are also supplied.

To compliment the HST38 hardware, the HST38S experimental software is available giving the student an opportunity to simulate the experiment before undertaking it, compare actual experimental data along side theoretical data and to capture, review, store and print actual and theoretical results. The HST38S has a graphical front end with actual experiment hardware images to create continuity and has all key experiment parameters being recorded.

  • To compare the deflections of a pin jointed truss with theory and to show structural efficiency
  • To implement the use of Castigliano's first theorem
  • The apparatus consists of 18 members, designed for construction of 3:4:5 triangle cantilever trusses, in one plane and 20.5° truss
  • Member linkages create true pin joints
  • Springing, for mounting the trusses, includes a sub-frame carrying a deflection measuring dial gauge
  • Joint deflections measured using dial gauge on movable mount
  • Comprehensive technical manual for student and lecturer and text book provided
  • Must be used in conjunction with HST1 Universal Frame and Stand (sold separately)
  • 2 year warranty
  • Comparison of experimental deflections with theoretical values derived from Castigliano's first theorem
  • Study of efficiency of different trusses
  • Construction of pin jointed trusses
  • Compare actual truss joint deflections with theoretical