PROPOSALS FOR CALCULATING THE BEARING CAPACITY OF KEY JOINTS OF PRECAST-CAST-IN-PLACE REINFORCED CONCRETE STRUCTURES OF CIVIL PROTECTION BUILDINGS

Abstract

Precast-cast-in-place structure of floors (coverings), walls (columns) are widely used in protective structures of civil protection, provided that the members are reliably connected both in their plane and in the perpendicular direction. The joint work of precast and cast-in-place concrete during design is ensured by calculation, constructive and technological measures. The need to calculate the specified joint is assumed A dependence for calculating the bearing capacity of key joints of precast-cast-in-place reinforced concrete structures, obtained on the basis of solving key and seam resistance problems by the variational method in the theory of concrete plasticity was proposed, taking into account the features of the stress-strain state of the failure zone and determining factors of influence. These include the key and seam parameters found in experimental studies. The parameters of a key include geometric ones (dimensions and their ratio, the angle of inclination of the supporting surfaces, the shape of the working section); strength characteristics (type and class) of concrete; reinforcement (strength, its quantity and location along the shear plane); the presence or absence of compression.  The proposed dependence has a regulatory structure, is more accurate compared to it and opens up prospects for improving constructive solutions of joints with increased shear resistance of load-bearing systems made of reinforced concrete.