Modelling Approaches for Inelastic Behaviour of RC Walls: Multi-level Assessment and Dependability of Results

Abstract

The severe damage and collapse of many reinforced concrete (RC) wall buildings in the recent earthquakes of Chile (2010) and New Zealand (2011) have shown that RC walls did not perform as well as required by the modern codes of both countries. It seems therefore appropriate to intensify research efforts towards more accurate simulations of damage indicators, in particular local engineering demand parameters such as material strains, which are central to the application of performance-based earthquake engineering. Potential modelling improvements will necessarily build on a thorough assessment of the limitations of current state-ofthe-practice simulation approaches for RC wall buildings. This work compares different response parameters obtained from monotonic analyses of RC walls using numerical tools that are commonly employed by researchers and specialized practitioners, namely: plastic hinge analyses, distributed plasticity models, and shell element models. It is shown that a multi-level assessment-wherein both the global and local levels of the response are jointly addressed during pre-and post-peak response-is fundamental to define the dependability of the results. The displacement demand up to which the wall response can be predicted is defined as the first occurrence between the attainment of material strain limits and numerical issues such as localization. The present work also presents evidence to discourage the application of performance-based assessment of RC walls relying on nonregularized strain EDPs.

Influence of Lap Splices on the Deformation Capacity of RC Walls. I: Database Assembly, Recent Experimental Data, and Findings for Model Development

“…Residual strength and strain: Upon the onset of lap splice degradation, the strength of most test units with lap splices dropped sharply whereas for two test units the loss of strength was more gradual (TW3 and VK2). Postpeak response modelling is a delicate task as it requires challenging procedures to match numerical and physical localization issues (Almeida et al 2012(Almeida et al , 2016Calabrese et al 2010). This applies in particular to brittle deformation mechanisms such as lap splices, which are often characterized by steep softening slopes.…”

Recommended modeling parameters and acceptance criteria for nonlinear analysis in support of seismic evaluation, retrofit, and design

“…Research by Coleman andSpacone (2011), Pugh et al (2015) and Almeida et al (2016) shows that if wall response is simulated using common concrete material models (e.g. Mander et al 1988, Saatcioglu andRazvi 1992) to define the softening portion of the compressive stress-strain envelope, simulated drift at onset of lateral strength loss is inaccurate and a function of the number of elements and/or fiber cross sections used per element.…”

Force-based higher-order beam element with flexural-shear-torsional interaction in 3D frames. Part II: Applications

“…2 depicts the comparison between the tip displacements given by the proposed HOBT and that of Heyliger and Reddy [2]. The results are normalised with respect to those provided by the EBBT, which for the assumed geometric and loading conditions (prismatic element, linear elastic behaviour and nodal loads), always provide the same solution; this holds independently of the number of elements (N) and type of formulation (displacement-based or force-based) [14].…”