Numerical and experimental investigations of hot driven riveting process on old metal structures

The assessment of the structural resistance of historical metal structures involves a depth understanding of many factors, such as the properties of the constructions materials and the structural behaviour of the connection mode. Available information regarding the behaviour of historical riveted connections is quite limited and more information about the residual strain and stress state is still needed in order to allow the preservation of these existing structures. This paper deals with the assessment of stress and strain field which exist around the rivet hole due to the hot riveting process. Experimental specimens were manufactured with riveting technique used in aged metal bridges and different metallic materials for the joined plates were considered. Strain and thermal measurements were done during and after the overall riveting process. The results of the experimental investigation allowed the assessment of the residual strain state and the thermal response of the riveted joint. The experimental results were then used for validation of a 2D axisymmetric model. On the basis of the results obtained, the pre-stress state can be evaluated as well as the stress concentration areas where fatigue cracks may initiate. Thus, the provide findings constitute a supportive tool for further studies regarding the assessment and rehabilitation of historical riveted structures.