Use of digital image correlation to connect fracture curves and sectional analysis for structural design of polyolefin fibre reinforced concrete elements

•The σ-ε relation of PFRC elements could be obtained using σ-w and lref.•lref links test results with the sectional analysis used in structural design.•A proportional factor between lref and CMOD is determined (λ)•Constant values of lref might not be reliable in PFRC structural uses.•An exponential relation is found between fibre volume fraction and λ. The boosting of the polyolefin fibre reinforced concrete (PFRC) usage for structural design requires that a connection between the laboratory standards and the structural codes be made. This study aims to fill this gap by combining laboratory mechanical test results, digital image correlation and numerical simulations. The σ-ε and σ-w relations in PFRC elements have been connected by means of a parameter that affects the strain of concrete (lref). lref depends linearly on the crack width and exponentially on the fibre dosage. A procedure that enables an accurate multilayer sectional structural analysis for PFRC structural elements has been obtained.