Tension forces of hanger ropes have been recognized and utilized as an important parameter for health monitoring of suspension bridges.Conventional vibration methods developed based on string theory have been utilized to estimate tension forces of relatively long hanger ropes without problem; however it is convince that the vibration methods are not applicable for short hanger ropes since the influence of flexural stiffness is significant.Therefore,as an alternative of vibration methods,a number of feasibility studies of system identification (SI) technique considering flexural stiffness of the hanger ropes are recently performed.However,most of the previous studies using SI technique considered the support condition as ideal hinge support.In this study,the influence of support stiffness to the tension estimation result obtained from SI technique is investigated with a numerical example and experimental test results of Kwang-ahn Suspension Bridge which is located in Busan,Korea.