Projects for a haulage company
First project
Siemelink was asked to check whether a 68-tonne load could be moved on eight crossed timber cribs (supports made of azobé hardwood). His calculation showed that the move could even be done with six cribs. He of course took into account the reduced compressive strength perpendicular to the grain and the material factor for timber. For the short-term ground pressure, a value of 0.1 N/mm² was used. The ground pressure exerts an upward load on the beams under the cribs, putting them in bending. For this move, he calculated the eccentricity of the load at which the structure would only just be adequate. This eccentricity did not occur, so the structure is adequate.
Second project
Calculation of prop spacings for moving a 25-tonne engine across the thick ground floor slab above a basement at a water board. For a given prop height, the maximum prop force can be determined. Under a centric, uniform load, this gives the bearing area per prop. However, allow for an uneven distribution of the engine load. Because of the high bending stiffness of the ground floor slab, this uneven load on the floor is passed on to the props more evenly. In addition, the slab carries a portion of the engine load, to be calculated, to the basement walls. The prop spacing can therefore be larger close to the foundation walls. For stability, cross-bracing is installed in every fifth bay in both the longitudinal and transverse directions. Install the props tight so that they do not deform too much under load. A propping plan was also drawn.