Jeen de Vries is Marketing Communications and Graphic Design at Prolyte Group.Other blogs by Jeen de Vries
Prolyte Campus blog: Centre Point Load test with 20m Verto span
Prolyte products are extensively tested to get better insights on the behavior of the product under (extreme) loading. It is also done to test the theoretical outcomes of the calculations in practice. In Europe the German TÜV is recognized as a certification authority. This certificate can be acquired by checking calculations against the Eurocode standards and by a live test being carried out to measure whether the values are achieved.
For the video below we rebuilt the setup for the TÜV certification, as the Prolyte Verto truss is TÜV certified.
A 21m (68.9ft) span of Prolyte Verto truss was tested, with a distance between the support points of 20m (65.6ft). As can be found in the loading table for the Verto truss, the maximum allowable Center Point Load (CPL) for this span is 237,3kg (523.6lbs). The loading data provided in the loading tables indicates the maximum loading, which can be supported from the truss, used as a single span.
Although a free span of 20m is not commonly used in daily practice, the test shows the maximum allowable span with the maximum allowable center point load (CPL) of the Verto truss. The deflection stays within the calculated range and proves that the methods of design and manufacture are correct and safe. Please keep in mind that the test shows a predominantly statically loading situation, as all trusses are calculated for.
The deflection of a truss shows the bending forces at work. Deflection is defined as “deformation under load” (more can be found in the Prolyte BlackBook). All parts of the Verto trusses were checked after the test for permanent plastic deformation – of which there was no sign. This is all within the theoretical tolerances as calculated. So hence we proved our theoretical calculations to match with practice.
Never exceed the maximum allowable deflection of a single span, the safety factors are there for a reason. For instance, power driven hoists will impose alternating forces (dynamic loads) that will cause the truss to swing up when starting and stopping a lifting operation, and will result in different behavior under loading. So stick to the allowable loading and always be safe!
Gear used for this test:
- Load Cell: ME-Sensors, 50KN, Sampling frequency f=10Hz (10 measurements per second).
- ProLyft Manual Chain Hoists 1000kg, rotating hand chain guide (PHC-1000RHG-0315).
- Test weight: concrete block of 1 tonne.