On 20.09.2023, we had the opportunity to load the half-swing staircase optimized with our STABILS steel fibres in spring 2023. The half-swing staircase was professionally assembled for the load test at the Vetra precast plant in Neermoor. In order to obtain usable measured values from the test, 15 measuring points were installed along the half-swing staircase. The measurement method was based on laser optical measurement.
The strategy was to start with half the live load of 1.5 kN/m² and then increase to 3.0 kN/m² and finally to 6.0 kN/m² The load levels were systematically increased, and after each load level the measuring points were compared by laser to determine whether any deformation of the prefabricated staircase had occurred.
It was astonishing that no deformation or cracking could be detected with the load of double the live load. It was quickly agreed that another attempt should be made to destroy the prefabricated staircase. A concrete block weighing 2300 kg was provided by Vetra Fertigteilwerk.
The concrete block was carefully set down in the area of the spiral using a crane and then the measurement was started. To the astonishment of everyone involved, only a deformation in the hundredths range was measurable, no cracking was recognizable.
The measurement results were evaluated and fed back to the structural design department for comparison with the calculations.
Conclusion of the successful and informative test:
Looking back on the test results, it is felt that there is still a great deal of potential for optimization in terms of conventional steel, component strength and the use of CO2-optimized cements in the area of prefabricated stairs.