Development Of Interaction Diagrams For RC
Sections Confined With CFRP Composites
Author(s)
P. Christou, A. Michael & Z. Neofytou
Abstract
The interaction diagram is a surface which defines the maximum capacity of
compression members that are subjected to axial force and bending moments. As
a result, these diagrams provide the engineers with an additional tool for the
design of such members. When the compression members are confined with FRP
their capacity increases, however in many cases the increase in capacity is
normally neglected which sometimes can lead to very conservative designs. This
work includes the development of interaction diagrams for circular compression
members confined with CFRP using the fiber model. The longitudinal
reinforcement is considered to be symmetric whereas the confinement can vary.
The method presented herein defines the location of the neutral axis and based
on that calculates the axial force and bending moment. A comparison of the
unconfined to the confined section shows a considerable difference in the
interaction diagram plot in the compression controlled region.
Keywords: interaction diagrams, confinement, section equilibrium, RC section
strength.
1 Introduction
The analysis of concrete columns using an analytical solution is not trivial. As a
result the analysis of columns is basically reduced to the development of the
interaction diagram and the plot of the load condition in order to define failure or
not for the section. Normally the confinement for compression reinforced
concrete sections is provided either by ties or spirals. However, other methods
and materials are used in the later years which can provide increased
confinement and thus satisfy the requirement for increased ductility. The column
wrapping with CFRP composites is a popular alternative for improving the
Keywords
interaction diagrams, confinement, section equilibrium, RC section
strength
Related Book
Other papers in this volume
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