Shear resistance evaluation of prestressed concrete bridge beams: fib Model Code 2010 guidelines for level IV approximations

Abstract

The design shear resistance of an existing structure can be evaluated with analytical design procedures and numerical procedures provided by non‐linear finite element analyses. The new fib Model Code 2010 proposes different calculation methods that fall into four different levels of approximation. As the level of approximation rises, so the complexity and the accuracy of the calculated shear resistance increases. Non‐linear finite element analyses belong to the highest level of approximation, but although they are more and more becoming a customary tool in the daily design process, building codes do not provide guidance on how to perform these analyses. This paper describes non‐linear finite element analyses performed on prestressed beams, which underwent shear failure during experimental loading, in order to assess and criticize the finite element approaches. The aim of this work is to propose guidelines for numerical simulations in order to reduce model and user factors. The results obtained from the non‐linear finite element analyses have been compared with the analytical results using different levels of approximation. The design shear resistance obtained with the highest level of approximation, level IV, derived from non‐linear finite element analyses, turned out to be higher than the design shear resistance obtained with analytical procedures (levels I/II/III).

Model uncertainties and bias in SHEAR strength predictions of slender stirrup reinforced concrete beams

“…8,9 The statistical assessment is performed for six shear prediction models namely the mean value prediction of (a) EN 1992-1-1 (EC2) variable strut inclination method (VSIM), 24 (b) Model Code 2010 shear level of approximation III (MC10 III) 25 as a general formulation of sectional shear equations based on simplified modified compression field theory (SMCFT) (c) ACI 318, 26 (d) the compression chord capacity model (CCC), 18 and (e) modified compression field theory (MCFT) as implemented by the analysis program response 2000 (R2k). 19 MCFT is a representative of the most advanced level of approximation IV in the fib Model Code 27 and R2k offers best estimate predictions. Section 3 describes the database of compiled experimental observations, 23…”

Solution strategy for non‐linear finite element analyses of large reinforced concrete structures

“…A review of results from blind prediction competitions shows that predictions of beams in bending and shear can result in coefficients of variation (COV) of 5–30 % and 10–40 % respectively [3]. Such scatter can be attributed to the solution strategy selected and has been found to increase as the skills of the analyst decrease [4–7]. In order to use NLFEA in practical design, a general, robust and stable solution strategy should thus be selected.…”

Postdiction of the Flexural Shear Capacity of a Deep Beam Without Stirrups Using NLFEM

“…Nowadays, general design provisions for structural concrete members such as Eurocode 1 and Model Code 2010 2 specify that the resistance of structural concrete members can be evaluated using NLFEM when a simplified analytical approach may not provide an estimation with sufficient accuracy. However, modelling with NLFEM has been shown to be sensitive to the choices of the modelling techniques and parameters, 3 and it becomes time consuming if one needs many trials to obtain a reliable simulation. With the intention of simplifying the modelling process for engineering application, the Dutch Ministry of Infrastructure and Water Management (Rijkswaterstaat) provided a Guideline for Nonlinear Finite Element Analysis of Concrete Structures RTD 1016-1:2017, 4 which deals with the modelling of concrete structures using smeared cracking based NLFEM.…”