Experimental Verification of Long-term Behaviour of Concrete Structures

Abstract

The first part is focused on description and evaluation of 4-point long-term bending test of untraditionally prestressed concrete slab. The system of prestressing has been developed to make construction of buildings faster and cheaper. It is based on prestressing of concrete bars with a small cross-sectional area. The bars are embedded into a thin concrete slab in the precasting plant. The slab is transported to the site; it forms a lost formwork for the final part which is cast in situ. The second part deals with long-term deformations of columns in a real building. Vibrating wire strain gauges were installed in two columns in the second underground floor of eight-storey office building. Four vibrating wire strain gauges in vertical direction were placed into the each of the columns. Other four vibrating wire strain gauges were installed into four laboratory cylinders and measured shrinkage strains. Measured values from the initial period (approx. 12 months) were compared with results of the first calculations and with values measured on laboratory specimens placed at the construction site.