Solid timber beams strengthened with steel plates – Experimental studies

• The application of steel plates is an effective way of strengthening timber beams susceptible to bending.
• The increase in the load-bearing capacity of the tested beams strengthened with steel plates amounted to as much as 100%.
• The increase in the stiffness of the tested beams strengthened with steel plates by as much as 60%.

This paper presents the results of tests carried out on solid timber beams made of new wood (NW) and old wood (OW), which were subjected to bending after they were strengthened with steel plates and an epoxy adhesive. The beam specimens tested varied in their strengthening configurations (including configurations applicable to heritage structures, which are acceptable from the conservation point of view). The results obtained when steel plates were used for strengthening were found to be comparable to those strengthened with FRP (fibre reinforced polymer) materials. The load-bearing capacity of the strengthened specimens increased by as much as 100% relative to that of unstrengthened reference specimens. The values of the load-bearing capacity of the wood–steel plate joint determined under tension and compression are also reported. The research shows convincingly the impact of moisture content of the wood on the load-bearing capacity of all glued joints. In all tested cases, the failure ran right through the wood. It should be noted also that sand blasting was used to ensure proper adhesion of steel plates to the wood.