tussensteun

Tussensteun is a structural element that provides support at intermediate points along a spanning element, such as a beam, arch, girder, or floor slab, between its end supports. It shares the load between supports and helps to reduce the effective span, which lowers bending moments and deflection and increases stiffness of the structure.

In bridges and buildings, tussensteunen are typically vertical columns or piers placed between the end supports (e.g., abutments or end piers). They bear loads from the span and transmit them to the foundation. They can be made of concrete, steel, or timber, and may include bearings to allow for movement due to temperature, shrinkage, or settlement.

Design considerations include the spacing of the intermediate supports, the anticipated loads (dead, live, wind, seismic), soil bearing capacity, and the interaction with the end supports. Proper detailing at the connection points is essential to accommodate movements and to prevent cracking or excessive stresses. In timber floors, intermediate posts can carry joists; in bridges they form piers that support the deck or beam.

Common related terms are eindsteun (end support) and draagvlak (load-bearing support). The concept also appears in scaffolding and formwork, where tussensteunen provide temporary support during construction.