Numerical Modelling of Reinforced Concrete Walls Encased in Polyvinyl Chloride Stay-In-Place Formwork
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Date
2015-09-25
Authors
Azam, Adnan
Advisor
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Publisher
University of Waterloo
Abstract
In structurally participating formworks, a new forming technique for reinforced concrete, referred to as stay-in-place formwork has recently emerged as a viable technique. This permanent new formwork system simplifies the construction process and reduces construction time. Two materials that are well-suited for this technique are fiber reinforced polymer and polyvinyl chloride.
This research presents a non-linear and three-dimensional finite element model for reinforced concrete walls with and without polyvinyl chloride stay-in-place formwork. There is a variety of commercial programs for three-dimensional finite element modelling, but they lack the ability to model a complex composite material such as reinforced concrete encased in a polyvinyl chloride stay-in-place forming system. For its high performance and extensive range of material modelling capabilities, the ABAQUS finite element package was used in the current study. Concrete was modelled using a concrete damage plasticity model, and steel bars were modelled using an elastic and perfectly plastic material. Perfect bond was assumed between concrete and steel. The polyvinyl chloride stay-in-place formwork was modelled using an elasto-plastic material. As with the concrete and steel, perfect bond was assumed between the polyvinyl chloride panels and the concrete.
Finite element results were validated using experimental results reported by Scott (2014). It was observed from the comparison that the proposed non-linear fine element model is capable of predicting the load capacity for the reinforced concrete walls with and without the polyvinyl chloride stay-in-place formwork. Predicted yield loads were in good agreement with the experimental data, with an average error of 6% for control walls, 7% for the polyvinyl chloride encased reinforced concrete walls with flat panels, and 3% for the walls encased with hollow panels. In addition, finite element ultimate (peak) loads showed good correlation with the experimental data. The average error for the control, flat panel and hollow panel encased walls were 3%, 3% and 13%, respectively.
A parametric study was conducted to investigate the effect of concrete compressive strength, thickness of polyvinyl chloride stay-in-place formwork, and the strength of polyvinyl chloride used in stay-in-place formworks. It was observed that the concrete compressive strength has a significant effect on the flexural strength of polyvinyl chloride encased reinforced concrete walls. As expected, the thickness and strength of the polyvinyl chloride used have a proportional effect on the behaviour of the encased reinforced concrete walls.