Pull-out Strength of Bar Glued-in Joints

Glued-in joints have several advantages with respect to the traditional mechanical connections generally used in beam design, such as higher stiffness, more uniform stress distribution, less bar corrosion problems and better appearance. Systematic studies have been performed to predict the pull-out capacity of the bars in the last years. The experimental tests presented in the paper were focused on the role of the steel strength and of the bar diameter to determine a ductile collapse instead of a fragile splitting failure. The data showed the importance of the bond level requested to yield the bars, which can remain under limit values, performed by timber elements, only for mild yield steel and correlated bar diameters, especially in case of reduced edge distances, as it is necessary to respect in glulam beams joints. Extensive experimental investigations with different strength steels, different bar diameters and different edge distances were carried out on specimens with one, two or three threaded rods.