## 1 Introduction  
An open-deck steel plate girder bridge has been used as a railway bridge in several countries for many years. In such a bridge, since a girder and the track are connected without a deck and ballast (Figure 1), the impact and vibration at the track, generated by train passage, is directly transmitted to the bridge. As a result, frequent damage to bridge members and a high level of noise can occur. The impact and vibration level can be amplified dramatically in the presence of rail joints and cause rapid deterioration of the stiffness and strength of the track, which leads to track irregularities and damage to bridge members and bearings [1, 2]. In most open-deck steel plate girder bridges, standard-length rails (about 20 m-50 m) are interconnected using rail joints and are installed on sleepers that are connected to a girder using a fastener. This girder-sleeper fastener is usually shaped like a reverse T, as shown in Figure 1, and has low and inconsistent longitudinal and lateral resistance properties. Before the ballast bridge became common, the impact and vibration problem of the open-deck steel plate girder bridge was not such a big issue. As urbanization progressed and the demand for a calm environment increased, these shortcomings have become more prominent, and open-deck steel plate girder bridges are being replaced by bridges with ballasts and decks. However, a large number of open-deck steel plate girder bridges are still being used in many countries, and, as a large cost is required to replace them with new bridges, a more economical way to solve these problems is needed. Installing CWR (Continuous Welded Rail) can provide much cheaper alternative by eliminating rail joints. [PERSON] et al. [3] reported that CWR can provide enhanced fatigue life of a track and better ride comfort, as well as a reduction in track maintenance costs. However, when installing CWR on a bridge, it is necessary to secure stability due to the additional axial stress of the rail caused by the track-bridge interaction (TBI). A solution for preventing the buckling of CWR, which is being practiced, is to reduce the additional axial stress due to TBI. [PERSON] et al. [4] reported that the additional rail stress of CWR induced by TBI can be reduced by using a special rail fastener, such as a ZLR (zero longitudinal restraint) rail fastener. [PERSON] et al. [5] proposed the sliding track system to reduce additional rail stress. By applying the sliding track system to a bridge, 80-90% of the additional axial stress can be reduced without the use of special rail fasteners, such as ZLR or RLR (reduced longitudinal restraint) rail fasteners. [PERSON] et al. [6] studied the buckling and rail break behavior of CWR on an open-deck steel truss bridge, depending on the longitudinal fastening profiles between the bridge and the track, and they proposed an optimal track-bridge fastening strategy. In the case of an open-deck steel bridge, the lateral resistance of the track is suddenly changed in the transition zones between the bridge and the embankment region if ordinary girder-sleeper fasteners (shown in Figure 1) are used. In this case, the buckling of the CWR track in the transition zone should be carefully examined in the installation of CWR [7]. Another method to secure the stability of the CWR on an open-deck steel bridge is to develop a new girder-sleeper fastener, because it is difficult to expect adequate resistance with girder-sleeper fasteners that are currently in use. By replacing current girder-sleeper fasteners with those can provide an appropriate lateral track resistance for a CWR track, the buckling problems can be prevented. Based on this concept, a new girder-sleeper fastener has been developed recently in Korea and it has been installed on an open-deck steel bridge that is in service, as shown in Figure 2. However, the design method of such devices has not been well established. Figure 1: Example of open-deck steel plate girder bridge.