Abstract : This research provides theoretical and experimental results on strengthening glulam wood beams with fibre reinforced polymers. The projected applications deal with composite bridge deck structures. The selected design is composed of glulam beams reinforced in tension by muli layers carbone fiber reinforced polymer (CFRP) plates inserted between wood lamellas. We show that this type of reinforcement, for a given ratio of CFRP, has a much better performance than that of the current method consisting in strengthening the lower surface of the beam by a single layer of composite. It is shown that the statistical distribution of tensile strength is narrowed by the presence of the composite. Thus, a reinforcement of thin CFRP plates, properly distributed between the lamellas, has a dual effect, the first, as expected, is the fact that CFRP reduces the stresses in wood, the second positive effect is a reduction of the statistical extent of tensile strength, which results in a increase of the characteristic tensile strength of wood. Taking into account reinforcements in the calculations can be simply carried out by redefining a characteristic strength of wood with the equivalent homogeneous properties of reinforced material. Furthermore, we show that there are features such as transverse cracks in the wooden lamellas caused by the tensional stresses are stopped by the reinforcement so much so that it is possible to obtain a pattern of multi-cracked fracture. A failure criterion for delamination of wood - composite interface is proposed and experimentally determined for this purpose. Finally, experiments on hybrid beams prototypes consisting in glulam - very high performance concrete - CFRP, is presented. The results validated the proposed method of distribution of the composite reinforcement.