Influence of the size and depth of a circumferential notch on the impact behavior of streetlights. A passive-safety concept

Impact tests on weakened streetlights were carried out using a high energy pendulum. The weakening mechanism consists of a circumferential notch at the base of the streetlight. The objective is twofold: firstly to reduce the maximum acceleration values during an impact which will lessen the potential injuries of the occupants of the vehicle and secondly to help avoid the installation of protective barriers, necessary when the supporting structure has no mechanical fuse, thus helping the failure with low energy absorption values. The machining of the notch is possible in streetlights already installed in the road, due to the fact that the actual values of the structural stiffness and strength of these structures are much higher than those values typically required by the external loadings (mainly wind actions). These preliminary tests have shown a significant decrease in the two parameters under analysis, maximum acceleration and absorbed energy, when using the circumferential notch. These results suggest it would be beneficial to perform a crash test following EN12767 in order to certify the streetlight.