ABSTRACT
Nonlinear analysis is recently well-established methodology for safety assessment of bridge structures. Efficient techniques of both nonlinear numerical analysis of concrete structures and advanced stochastic simulation methods have been combined in order to offer an advanced tool for assessment of realistic behavior of concrete structures and reliability assessment. The combination of structural analysis and reliability assessment is presented together as the SARA software – a software shell which controls the communication between following individual programs: ATENA – FEM nonlinear analysis of concrete structures and FReET – the probabilistic engine based on stratified Monte Carlo type Latin Hypercube Sampling. As an application example the nonlinear reliability analysis of a reinforced concrete bridge (2-2043-15 E4 Kristineberg) in Stockholm has been performed. Simulated results are compared with the results from deterministic nonlinear analysis and from experiments. The utilized approach is based on randomization of the nonlinear fracture mechanics finite element analysis of concrete structures. Theoretical as well as practical application issues will be presented emphasizing key points of the solution.
Note that the studied reinforced concrete bridge has a two-span frame structure. Total bridge length is 26 m; bridge deck has a width of 7 m. The computation model has been created using software ATENA 3D. For concrete has been used the constitutive model CC3DNonLin Cementitious, values of the material model parameters are based on laboratory experiments of concrete cubic strength in individual parts of the bridge taken during casting. The class B500B of reinforcement steel was used. Values of parameters for material model CCReinforcement were exctracted from quality certificate of steel producer. The basic variables material parameters of concrete and reinforcement were randomized. Statistical correlation among some variables have been considered and imposed in Monte Carlo type simulation by simulated annealing approach. The values of perpendicular displacements obtained from experiments for two load cases were compared with both deterministic and stochastic simulation results (Fig. 1). Also deterministic and probabilistic results of maximal crack widths in particular critical part of the bridge are presented. The obtained variability is large for both load cases, 40% app. Experiment (empty green symbol), deterministic simulation (full red symbol) and PDF of perpendicular displacement for selected monitoring point. https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781315207681/cd556cd4-4dcf-4efe-8e29-56fc67b8bfbd/content/fig348_1.tif"/>
