HYBRID WALL- AND CEILING-SLABS MADE OF TIMBER AND ANHYDRITE FLOOR LAYER FOR MULTI-STOREY TIMBER HOUSES - DEVELOPMENT AND INVESTIGATION WITH LARGE-SCALE SPECIMENS, NUMERICAL SIMULATION AND CLOSE-RANGE PHOTOGRAMMETRY

摘要

A sustainable stewardship of available resources requires a comprehensive ecological concept for the construction of multi-storied timber buildings. Therefore the developed hybrid composite system combines the excellent properties of the used natural building materials wood and anhydrite floor with embedded natural fibers. Timber-anhydrite-slabs as well as anhydrite layered walls of timber stacks are made with this system. To estimate the load-bearing and deformation behaviour as a bracing structure in multi-storey buildings, experimental investigations on large-sized wall panels have been done and compared with plywood board walls and practice-related wood panel constructions for a first assessment of the load-carrying capacity of the new composite wall elements. The wall panels consisted of timber elements with hardwood dowels and an anhydrite floor layer. In addition to the direct interconnection of anhydrite with an unplanned wood surface supplementary elements have been applied. These are trapeze bars or galvanized edges profiles to allow an extra securing of the screed layer. The direct comparison of the series investigated experimentally showed a significant influence of the mineral surface in the experimental as well as in the numerical tests. The assessment of the developed solutions considering load applications, eccentricities and safety requirements, serviceable life and building physics was determined by the verification of the developed structural models with experimental investigations and measurement done by Close-Range Photogrammetry. Additionally large-scale ceiling slabs with full surface composite action have been tested under static and low-cycle bending loads to investigate the structural behaviour in a serviceable life period of nearly eighty years. For serviceability, the natural interconnection can be described as a stiff connection like clued mounting. The tests proved that the hybrid elements are useful lightweight slabs with high load-bearing capacity even in long time use.