Generalized Nonlinear Moment-Curvature Model for Serviceability-Based Design of Hybrid Reinforced Concrete

Abstract

A generalized formulation for the flexural response of FRC and hybrid sections using multi-linear tension and compression models with any number of segments and rebar layers. Closed-form expressions for neutral axis depth and moment remove the need for iterative sectional analysis.

Summary

Sectional analysis of fiber reinforced and hybrid reinforced concrete is usually numerical. This work generalizes the closed-form approach so that the tension response, the compression response, and the reinforcement layout may each take an arbitrary number of linear segments and layers.

The formulation produces the complete moment-curvature response in closed form, with strain compatibility and force equilibrium satisfied exactly in each regime. It contains the earlier bilinear and trilinear models of the group as special cases and extends them to layered and sandwich sections.

The solutions are implemented in the group's analysis engines and drive the batch back-calculation pipeline used to build validation databases across hundreds of test records.