Analytical Considerations for Reinforced Concrete Walls in the Design Practice in Chile

Abstract eng:
Slender rectangular walls with discontinuities at their bases, such as flag walls (setback) or walls with door openings or access, are common in Chilean practice because of the architectural requirements at facades, first floors and underground. Also, the architectural requirements and Chilean idiosyncrasy have forced to the designers to use several wall sections located in a vast area of the floor plan, resulting in many cases in T-shaped walls, with long webs or flanges, which produced large amount of reinforcement in the boundary elements. Many of these types of walls were imposed with large displacement demands in the 2010 Maule earthquake in Chile, and presented flexo-compression failures in the boundary elements, often close to their discontinuities. These observations have shown the need to establish good predictors of compressive or tensile strains in concrete or steel in reinforced concrete shear rectangular with discontinuities and T-shaped walls that leads to limit states or confinement requirements. However, there is limited information about the behavior of such elements, and no designs or guidelines in the current codes consider the effects of discontinuities at the base and the effect of T-shaped walls, especially with long flanges or web. In this work, a series of analysis that help to incorporate the effect of discontinuities and cross-section, along with different aspect ratios and other considerations in the yield and ultimate curvature, compressive amplification or tensile reduction strains in concrete or steel, and effective flange width for the designs of slender walls are presented, and design recommendations are proposed. First, the elastic and inelastic components of flexural deformations by means of a fiber model for slender rectangular walls is calibrated and it was found that the elastic component is dependent on the axial load and the boundary steel reinforcement ratio. Additionally, two analytical models are presented that estimate the yield displacement, yield curvature and ultimate curvature of walls with openings, such as flag walls (setback), mainly based on the dimensions of the opening calibrated from a parametric analysis of a non-linear finite element model. The results indicate that these discontinuities can reduce the elastic displacement, due to the presence of a more rigid section above the opening, and in the inelastic component, increasing the strain demands at the base because the opening tends to constrain the plastic hinge within that area. Lastly, in addition of predictors of maximum tensile and compressive strains for T-shaped walls, the effective flange width for different aspect ratios, length of the flange and the web, is studied and compared with actual code recommendation.

• Export as: BibTeX | MARC | MARCXML | DC | EndNote | NLM | RefWorks
• Add to your basket