Timber engineering has advanced over recent decades to offer an alternative to traditional materials and methods. The bonding of fibre reinforced plastics (FRP) with adhesives to timber structures for repair and strengthening has many advantages. However, the lack of established design rules has strongly restrained the use of FRP strengthening in many situations, where these could be a preferable option to most traditional techniques. A significant body of research has been carried out in recent years on the performance of FRP reinforced timber and engineered wood products. This paper gives a State of the Art summary of material formulations, application areas, design approaches and quality control issues for practical engineers to introduce on-site bonding of FRP to timber as a new way in design for structural repair and rehabilitation.

Connections with metal dowel-type fasteners are important details in timber construction, connecting single members and elements to larger structures. The load-carrying capacity can be described by different failure modes of the fasteners and in the surrounding timber. These failure modes show a dependency on different dimensions and material properties.The failure can be classified into brittle and ductile failure modes based on the deformation capacity. The limited deformation capacity of the brittle failure modes has an impact on the load-carrying capacity of the entire connection with multiple fasteners. The present study takes a critical appraisal of load-carrying capacity and deformation capacity of timber connections and the implementation of their design in the Eurocode 5. By aiming for the ductile failure modes with plastic deformation of the fasteners in the design of the connection, high load-carrying capacities and high reliability can be achieved. For brittle failure modes the reduced resistance and the reduced reliability should be accounted for, especially for connections with multiple fasteners.

change in different ways: elastic -decreases, and plastic -remains at the same marks with slight deviations in one direction or another. The initial modulus of elasticity of the studied samples is greater by 23-55%.It was found that the strength of deeply modified materials by the polymer composition "Silor" increases in the range of 17-21%, deformability (critical relative deformation) is reduced by 7-20%, and the initial modulus of elasticity increases significantly by 26-35% compared with wood of the same breeds modified superficially.The sixth section describes the scope of valid (complete) and optimized (with a limit at the point of boundary deformation) diagrams of "stress -strain". Using such diagrams, the mathematical apparatus of calculation of various elements and constructions on the basis of continuous, glued and modified wood is improved.

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