Seite - 1225 - in Book of Full Papers - Symposium Hydro Engineering

(a) (b) Fig. 2. (a) Non-over-flow monolith of Pine Flat dam used in this study (all dimensions are in meters). (b) finite element mesh of the dam and part of the reservoir. The nonlinear behavior of dam concrete is modeled using plastic-damage method. In this method, the stiffness of the concrete is degraded beyond its strength using a reduction coefficient of (1-dt), where dt is the tensile damage parameter which is assumed to be function of the plastic strains. The damage parameter can take values from zero, representing the undamaged material, to one, which represents total loss of strength. Previous research on this dam showed that only the tensile damage is important in its seismic performance. It is related to concrete tensile cracking which is one of the most important failure modes of gravity dams. The constitutive behavior of the dam concrete is shown in Fig. 3. The finite element mesh of the dam body has been sufficiently refined such that it properly captures its nonlinear response. The concrete properties are: mass density of 2400 kg/m3, initial elastic modulus of 30 GPa, Poisson’s ratio of 0.2, and tensile strength of 2.9 MPa. The water has density of 1000 kg/m3 and Bulk modulus of 2.07 GPa. Fig. 3. Constitutive behavior of mass concrete in uniaxial tension 0 0.5 1 1.5 2 2.5 3 3.5 0.0000 0.0001 0.0002 0.0003 0.0004 0.0005 Tensile Strain f t d t = 0.00 0.38 0.62 0.76 0.85 0.91 0.96 0.99 E0 (1-d t)E0 1225