Nonlinear dynamic response of cracked reinforced concrete nuclear containment vessels

In the design of reinforced concrete nuclear vessels horizontal cracks are assumed to exist as a result of pressurization. Seismic shear forces must be transmitted across these cracks. The nonlinear dynamic response of cracked vessels is studied. The force-displacement relationship across the cracks are taken from the experimental investigation that included the shear transferred by the concrete but not by dowel action of the vertical steel. The stiffness is highly nonlinear, hysteretic, and degrading. A modal analysis technique, based on an eigenvalue reanalysis procedure, is developed and it is compared with a direct numerical integration solution. Only typical response values are given for particular values of the variables and for one particular earthquake input.