Deterioration of submerged parts of the piers of concrete bridges was a trigger of studying of concrete samples extracted from the structures in operation. Extracted concrete cores were never exposed to air: drilling, preparation and testing of the cores were executed so that cores were permanently immersed into water. Compression test of completely water-saturated cores revealed that squeezing out of water contained in the pore space of loaded concrete caused increase of modulus of elasticity, change of the stress state and, in the long run, inevitably resulted in the progressive deterioration of concrete exposed to varying load (even under small magnitudes).rnThe two-level mathematical model of viscoelasticity with unilateral constraint on tension condition is described.rnThe specific peculiarities of deformations of completely water-saturated concrete have a direct influence on the stress state of structures, including their seismic resistance. Therefore, it has to be taken into consideration in design and evaluation of condition of such structures like bridge piers, offshore drilling and producing platforms, etc.
展开▼
