In aquariums were often used building elements of acryl glass (pmma). To this count flat glands, two-wheel bent building elements (e.g. for tunnels) or biaxial bent building elements (e.g. hemispheres). More and more common bonded constructions make new demands on dimensioning. Also in this field static calculations are just a column in verifications of stability, which in the ISP are ideally amended by other departments. So stress compatible determinations of material characteristics and later inspections of construction works with a displacement measurement by initial fills are coupled close to static calculations.