Numerical investigation of the behavior of demountable composite steel‐CLT‐concrete floors

Abstract

This study examines the mechanical behavior of demountable composite floor systems that combine steel profiles, cross‐laminated timber (CLT) panels, and precast concrete elements. These hybrid systems exploit the complementary properties of their materials, combining the compressive strength of concrete, the stiffness and ductility of steel, and the advantages of timber lightness, prefabrication, and environmental performance within a circular, reversible construction approach. The work is based on a finite element numerical modeling framework, the main assumptions of which were previously established and validated through experimental and numerical investigations of demountable steel‐concrete composite systems, including push‐out and bending tests. The framework was then extended to steel‐CLT‐concrete configurations to investigate the shear behavior of various demountable connection solutions using simulated push‐out tests and the global flexural response of composite beams under three‐point bending. Numerical analyses enable a comparative assessment of different connection configurations in terms of stiffness, load‐bearing capacity, and load transfer mechanisms. These analyses also allow for an evaluation of the configurations' ability to develop a high degree of composite action while preserving demountability. The results underscore the significant impact of connection design on the overall performance of demountable steel‐CLT‐concrete composite floors. These findings are used to identify promising connection solutions that perform well mechanically and are reversible, in support of an ongoing experimental campaign involving push‐out and bending tests on steel‐CLT‐concrete systems.