Effect of Counterforts and Buttresses on Retaining Wall using Finite Element Analysis

Abstract

Retaining walls are used with tying with more than one wall at perpendicular joints to retain liquids, water storage and materials storages such as dyke walls and tanks. Retaining walls excessively used in culverts and as well as in the bridges i.e., construction of abutments, wing walls supposed to resist soil pressures, applied perpendicular to the axis of the walls. Due to in-sufficient land and based on the present construction scenario followed in the construction of retaining structures, the wall height is often increased, thereby increasing the cost of construction of sub structure. The values of the bending moment at the base increases due to the increase in the height of the wall resulting in higher sections which is uneconomical. The need of having safe and economical section shall be achieved by transforming the structural system of retaining wall i.e., by introducing supports to the vertical wall thus decreasing the thickness of stem. The design of rigid retaining wall either Cantilever or Counterfort or Buttress retaining wall is based on pressure exerted by the retaining material, wall slope, height, ease of construction and stability. When the retaining wall height is more than 8 m, the selection of extra supports i.e., either counterforts or buttresses is based upon the designer’s experience. By conducting comparative study on resisting forces for varying heights, the behaviour of these supports on retaining wall can be depicted. The depiction of forces can be achieved by running an analysis in STAAD.pro with preliminary dimensions and soil parameters respectively. Resisting forces from counterfort and buttress supports on retaining wall are equal when the height is in between 9 m to 24 m but buttress support has shown less resisting forces when the height is less than 9 m.