Three‐dimensional beam‐truss model for reinforced concrete walls and slabs – part 1: modeling approach, validation, and parametric study for individual reinforced concrete walls

Abstract

SUMMARYA three-dimensional beam-truss model for reinforced concrete (RC) walls developed by the first two authors in a previous study is modified to better represent the flexure-shear interaction and more accurately capture diagonal shear failures under static cyclic or dynamic loading. The modifications pertain to the element formulations and the determination of the inclination angle of the diagonal elements. The modified beam-truss model is validated using the experimental test data of eight RC walls subjected to static cyclic loading, including two non-planar RC walls under multiaxial cyclic loading. Five of the walls considered experienced diagonal shear failure after reaching their flexural strength, while the other three walls had a flexuredominated response. The numerically computed lateral force-lateral displacement and strain contours are compared with the experimentally recorded response and damage patterns for the walls. The effects of different model parameters on the computed results are examined by means of parametric analyses. Extension of the model to simulate RC slabs and coupled RC walls is presented in a companion paper.

High Performance Damage‐Resistant Seismic Resistant Structural Systems for Sustainable and Resilient City: A Review

“…The experimental results indicated that the shear capacities of shear wall systems with replaceable fuses were close to that of the conventional shear wall system. Moreover, the inelastic deformation and damage of specimens were concentrated in the fuse section as expected [44,45]. In order to reduce the damage at the bottom of the shear wall, new replaceable foot parts for the shear wall were proposed [46]; it was experimentally revealed that the proposed foot parts wall could greatly minimize the damage at the bottom of the shear wall.…”

Three‐dimensional beam–truss model for reinforced concrete walls and slabs – part 2: modeling approach and validation for slabs and coupled walls

“…The effect of aggregate interlock is not modeled. Confined edge beams in the slab, such as that shown in Figure (a), are modeled with beam elements that have flexural rigidity in and out of plane, similar to the boundary elements of RC walls as discussed in the companion paper . For the slab BTM, the torsional rigidity of each beam is modeled as bilinear perfectly plastic, with the gross elastic torsional rigidity up to the torsional cracking strength, which is calculated based on the space truss model for torsion .…”

“…The strut running from the bottommost coupling beam to the base corner is used to determine the diagonal angle. The nominal moment capacity of the wall is the moment for which the peak tension strain of longitudinal steel reaches 1% or the peak compressive strain of concrete reaches 0.3%. If V b , cp is smaller than that required for case , the coupled walls are treated as individual walls uniform over their height when determining the diagonal angle (i.e., using the diagonal angle determination for walls uniform over their height; see the companion paper ). The effect of the coupling forces M A , M B , and V cpl is taken into account when calculating M n for the first estimate of diagonal angle.…”

“…2. If V b,cp is smaller than that required for case (1), the coupled walls are treated as individual walls uniform over their height when determining the diagonal angle (i.e., using the diagonal angle determination for walls uniform over their height; see the companion paper [1]). The effect of the coupling forces M A , M B , and V cpl is taken into account when calculating M n for the first estimate of diagonal angle.…”

“…As described in Lu and Panagiotou [9], the main modeling approaches for RC walls are as follows: (1) fiber-section beam-column element models; (2) wide column models known also as equivalent frame models; (3) two-dimensional (2D) truss models; (4) three-dimensional (3D) truss models; (5) beam-truss models (BTMs); and (6) finite element (FE) models, using either plane stress or solid elements. Approaches (1) and (2) are often used to model RC wall buildings. For example, Calugaru and Panagiotou [10] modeled 20-story RC core wall buildings including slabs and columns with modeling approach (1), and Coelho et al [11] modeled the five-story RC coupled wall specimen discussed in this paper with modeling approach (2).…”