This paper presents a vibration-based structural health monitoring (SHM) technique using a high sensitive wireless
sensor node for caisson-type breakwater. To achieve the objective, the following approaches are implemented. Firstly,
vibration-based SHM method is selected for caisson-type breakwater. The feasibility of the vibration-based SHM
method is examined for the caisson structure by FE analysis. Foundation loss damage is considered as the damage of
caisson-type breakwater. Secondly, a wireless SHM system with a high sensitive wireless sensor node is designed. The
sensor node is built on an imote2 platform. The vibration-based SHM method is embedded on the sensor node. Finally,
the performance of the wireless SHM technique is estimated from experimental tests on a lab-scaled caisson. The
vibration responses and damage monitoring results are compared with the proposed wireless system and conventional
In this study, wireless structural health monitoring (SHM) system of cable-stayed bridge is developed using Imote2-
platformed smart sensors. In order to achieve the objective, the following approaches are proposed. Firstly, vibrationand
impedance-based SHM methods suitable for the pylon-cable-deck system in cable-stayed bridge are briefly
described. Secondly, the multi-scale vibration-impedance sensor node on Imote2-platform is presented on the design of
hardware components and embedded software for vibration- and impedance-based SHM. In this approach, a solarpowered
energy harvesting is implemented for autonomous operation of the smart sensor node. Finally, the feasibility
and practicality of the multi-scale sensor system is experimentally evaluated on a real cable-stayed bridge, Hwamyung
Bridge in Korea. Successful level of wireless communication and solar-power supply for smart sensor nodes are verified.
Also, vibration and impedance responses measured from the target bridge which experiences various weather conditions
are examined for the robust long-term monitoring capability of the smart sensor system.
This study presents vibration-based structural health monitoring method in foundation-structure interface of harbor
caisson structure. In order to achieve the objective, the following approaches are implemented. Firstly, vibration-based
response analysis method is selected and structural health monitoring (SHM) technique is designed for harbor caisson
structure. Secondly, the performance of designed SHM technique for harbor structure is examined by FE analysis. Finally, the applicability of designed SHM technique for harbor structure is evaluated by dynamic tests on a lab-scaled caisson structure.
In this study, a technique using wireless impedance sensor node and interface washer is proposed to monitor prestressforce
in PSC girder bridges. In order to achieve the goal, the following approaches are implemented. Firstly, a wireless
impedance sensor node is designed for automated and cost-efficient prestress-force monitoring. Secondly, an
impedance-based algorithm is embedded in the wireless impedance sensor node for autonomous prestress-force
monitoring. Thirdly, a prestress-force monitoring technique using an interface washer is proposed to overcome
limitations of the wireless impedance sensor node such as measureable frequency ranges with narrow band. Finally, the
feasibility and applicability of the proposed technique are evaluated in a lab-scaled PSC girder model for which several
prestress-loss scenarios are experimentally monitored by the wireless impedance sensor node.
Among many damage types, prestress-loss in tendon is the major one that should be monitored in its early stage in order
to secure the safety of PSC girder bridges. This damage-type obviously change vibration characteristics, but with
apparent difference depending on sensing mechanism as well as information analysis. Recently, there have been research
efforts to develop wireless smart sensor nodes embedded damage monitoring algorithms for various sensing
mechanisms. In this study, vibration-based damage monitoring algorithms which are appropriate for the smart sensor
nodes to alarm the occurrence of prestress-loss in PSC girder bridges are presented. Firstly, two sensing mechanisms are
considered for vibration characteristics: one is acceleration and the other is electro-mechanical impedance. Also, four
acceleration-based algorithms and three impedance-based algorithms are selected to extract features from those signals.
Secondly, the performances of those selected methods are evaluated using a large-scaled PSC girder for which a set of
acceleration-impedance tests were measured for several prestress-loss scenarios by using both commercial instruments
and a wireless smart sensor node.