Experimental study on the performance of notched round timber sections

Abstract Round timber beams are generally notched at the ends for seating purposes. This notching creates a weakness in the section due to the concentrations of stress at the sharp corner. Very little research has been undertaken with regard to the behaviour of, and design procedures for, notched round timber sections. This experimental program studied the performance of various profiles of notches in round timber beams under three-point loading and compared them to nominal capacities for round sections determined using Australian and international design standards. Test results showed an increase in load capacity of round timber beams by 13% and 26% for a tapered notch of 1:2 and 1:4, respectively, compared to a stepped notch with a 1:0 slope. Round sections with all the timber below the notch removed were also tested. Ultimate flexural failure in the notch removed sections occurred on average at loads 29% higher than for the stepped notch, although there was a loss of stiffness in the section of 30%.