Decarbonizing construction requires structural concepts that reduce material use while maintaining safety and performance. Carbon-reinforced concrete (CRC)—with high tensile capacity, low self-weight, and corrosion resistance—enables a shift from massive members to thin-walled elements with complex, performance-driven geometries. Origami-inspired folded shells are a promising example, but robust nonlinear modeling approaches for CRC folded elements are still under development and remain insufficiently validated and systematized for design-oriented studies. This contribution advances a nonlinear FE modeling approach for folded CRC modules based on a resolved representation of the shell's cross-section with reinforcement grids. The concrete is discretized as a 3D continuum and described by a coupled fracture–plastic constitutive formulation: Rankine-type cracking with crack-band regularization and exponential tension softening, combined with compressive plasticity governed by a Menétrey–Willam failure surface. The carbon reinforcement is modeled explicitly by embedded beam elements with perfect bond to the concrete. This modeling framework is designed to capture the characteristic behavior of thin-walled strain-hardening composites exhibiting multiple finely distributed crack patterns. The macroscale model parameters are identified from composite tensile tests and from in-plane compression-shear tests using the TorAx test setup. Building on this modeling approach, we conduct a compact parametric study varying reinforcement ratio while keeping geometry, boundary conditions, and loading fixed. The simulations quantify trends in peak load, crack patterns, and governing failure mode, providing first-order guidance for reinforcement-efficient design of thin-walled folded CRC structures.