Nonlinear finite element reliability analysis of Concrete-Faced Rockfill (CFR) dams under static effects

The response of concrete slab on Concrete-Faced Rockfill (CFR) dams is very important. This study investigates the reliability of the concrete slab on a CFR dam by the improved Rackwitz–Fiessler method under static loads. For this purpose, ANSYS finite element analysis software and FERUM reliability analysis program are combined with direct coupled method and response surface method. Reliability index and probability of failure of the concrete are computed in the all critical points of the concrete slab by dam height. This study is also expanded for the reliability of CFR dams including different concrete slab thickness. In addition to the linear behavior, geometrically and materially non-linear responses of the dam are considered in the finite element analysis which is performed with reliability analysis. The Drucker–Prager method and the multi linear kinematic hardening method are, respectively, used for concrete slab and for rockfill and foundation rock. Finite element model used in the analyses includes dam–reservoir–foundation interaction. Reservoir water is modeled by the Lagrangian approach. Welded and friction contact based on the Coulomb’s friction law are considered in the joints of the dam. One-dimensional two noded contact elements are used to define friction. The self-weight of the dam and the hydrostatic pressure of the reservoir water are considered in the numerical solutions. According to this study, hydrostatic pressure, nonlinear response of the rockfill and the decrease in the concrete slab thickness reduce the reliability of the concrete slab of the CFR dam. Besides, the CFR dam models including friction are safer than the models including welded contact in the joints.

[1]  P. Alart,et al.  A mixed formulation for frictional contact problems prone to Newton like solution methods , 1991 .

[2]  Robert E. Melchers,et al.  Structural Reliability: Analysis and Prediction , 1987 .

[3]  Maurice Bryson,et al.  Probability, Statistics, and Reliability for Engineers , 1997, Technometrics.

[4]  Temel Türker,et al.  Near-fault ground motion effects on the nonlinear response of dam-reservoir-foundation systems , 2008 .

[5]  K. G. Sharma,et al.  Constitutive Model for Rockfill Materials and Determination of Material Constants , 2006 .

[6]  R. Rackwitz,et al.  Structural reliability under combined random load sequences , 1978 .

[7]  D. Q. Li,et al.  Reliability analysis of embankment dams using Bayesian network , 2009 .

[8]  Michel Massiéra,et al.  RELATION BETWEEN MONITORING AND DESIGN ASPECTS OF LARGE EARTH DAMS , 2006 .

[9]  Peter Wriggers,et al.  Computational Contact Mechanics , 2002 .

[10]  J. C. Simo,et al.  Algorithmic symmetrization of coulomb frictional problems using augmented lagrangians , 1993 .

[11]  Temel Türker,et al.  Comparison of near- and far-fault ground motion effect on the nonlinear response of dam–reservoir–foundation systems , 2009 .

[12]  Murat Emre Kartal,et al.  Reservoir water effects on earthquake performance evaluation of Torul Concrete-Faced Rockfill Dam , 2009 .

[13]  J. Christian,et al.  Reliability Applied to Slope Stability Analysis , 1994 .

[14]  R. H. Myers,et al.  Response Surface Methodology: Process and Product Optimization Using Designed Experiments , 1995 .

[15]  Azm S. Al-Homoud,et al.  Modeling uncertainty in stability analysis for design of embankment dams on difficult foundations , 2004 .

[16]  J. Oden,et al.  Contact Problems in Elasticity: A Study of Variational Inequalities and Finite Element Methods , 1987 .

[17]  Alemdar Bayraktar,et al.  Asynchronous seismic analysis of concrete-faced rockfill dams including dam–reservoir interaction , 2005 .

[18]  Nasim Uddin.  A dynamic analysis procedure for concrete-faced rockfill dams subjected to strong seismic excitation , 1999 .

[19]  Luan Mao-tian.  Reliability analysis of concrete-faced rockfill dam′s slope stability and its application , 2002 .

[20]  P. B. Schnabel.  SHAKE-A Computer Program for Earthquake Response Analysis of Horizontally Layered Sites , 1970 .

[21]  C. Bucher,et al.  A fast and efficient response surface approach for structural reliability problems , 1990 .

[22]  K. Sassa,et al.  Reliability Analysis for Effects of Reservoir Water Level Change on Embankment Dam , 2007 .

[23]  Christian Bernstone,et al.  Structural Assessment of a Concrete Dam Based on Uplift Pressure Monitoring , 2009 .

[24]  Edward L. Wilson,et al.  Finite elements for the dynamic analysis of fluid‐solid systems , 1983 .

[25]  M. Evans,et al.  SHEAR MODULUS AND DAMPING RELATIONSHIPS FOR GRAVELS , 1998 .

[26]  Palle Thoft-Christensen,et al.  Structural Reliability Theory and Its Applications , 1982 .

[27]  Murat Emre Kartal,et al.  The effect of concrete slab–rockfill interface behavior on the earthquake performance of a CFR dam , 2011 .

[28]  Robert Y. Liang,et al.  A reliability based approach for evaluating the slope stability of embankment dams , 1999 .

[29]  Gautam Bhattacharya,et al.  Direct search for minimum reliability index of earth slopes , 2003 .

[30]  Murat Emre Kartal,et al.  Linear and nonlinear response of concrete slab on CFR dam during earthquake , 2010 .

[31]  Murat Emre Kartal,et al.  Seismic failure probability of concrete slab on CFR dams with welded and friction contacts by response surface method , 2010 .