Analytical investigation of timber beams strengthened with composite materials.

Graphical abstract Highlights • Analytical model for designing flexural strengthening of timber beams with FRPs. • Definition of an amplification factor (β) for the plastic compressive stress area. • Use of natural FRPs as greener and suitable alternative to classic FRPs. • Calibration and validation of the model on the flexural behavior of timber beams. Abstract Wood has always been considered as a valuable material for construction works. Nonetheless, over time timber structural components may need to be strengthened with other materials such as steel or, more recently, Fiber Reinforced Polymer (FRP) composites. This research paper concerns an analytical investigation based on the results of an experimental campaign carried out at the University of Padova (Italy) on full-scale timber beams flexure-strengthened by carbon and natural flax fibers. The theoretical work was carried out by means of a MATLAB code to develop an analytical model based on beam theories. This was then followed by calibration of the model with pilot tests and comparison of the results with those from other tests. During calibration, an equation for amplification coefficient of the plastic compressive stress block was developed. The analytical model and its related equations, including the amplification coefficient, can be used to model other timber beams by changing the significant mechanical parameters, boundary and loading patterns, providing a general procedure for designing flexure intervention on existing timber beams. [ABSTRACT FROM AUTHOR]