A DESIGN CONSTRUCTION OF THE SOCKET ANCHORING SYSTEM BETWEEN STEEL PIER AND THE FOUNDATION IN MORIGUCHI JCT
Moriguchi JCT which is under construction is the ramp connecting Hanshin Expressway Moriguchi Route with Kinki Expressway. Because the foundation of the ramp bridges are strictly limited in space due to the underground installation, the socket anchoring system was adopted instead of the conventional anchor frame system. This system is one of the methods to anchor the steel pier into the foundation and consists of steel pier with PBL and socket steel pipe. Main reinforcements of the foundation are arranged and in situ concrete is filled between the steel pier and socket steel pipe and inside the steel pier. This paper summarize a construction of the socket anchoring system adapted to the highway bridge for the first time. Although socket anchoring system is adopted by some railroad structures and few road structures. Introduction Moriguchi JCT connects Hanshin Expressway Moriguchi Route with Kinki Expressway (Figure 1) Moriguchi JCT will disperse the traffic concentrated in the center of Osaka city, prepare alternative route at the time of the accident or disaster, and mitigate congestion at local street by connecting Hanshin Expressway Moriguchi Route and Kinki Expressway. 1 Hanhin Expressway Company Limited, Osaka, Japan Figure 1 Moriguchi JCT construction site For Kyoto For Osaka city Kinki Expressway Osaka Monorail Moriguchi Route Osaka prefectural road No.2 National road No.1 Pier AP3 Moriguchi JCT is surrounded by Hanshin Expressway Moriguchi Route (about 40,000 cars/day) Kinki Expressway (about 90,000 cars/day) Osaka prefectural road No.2, National road No.1 (about 100,000 cars/day) and Osaka Monorail. These structures make construction space very narrow. Moreover, by widening the existing RC piers and RC slabs, construction of Moriguchi JCT is very difficult. This paper reports the socket anchoring system adopted in order to widen the existing piers and slab in the narrow construction space. 1. Structure summary The outline of the socket anchoring system is shown Figure 2. This system is one of the methods to anchor the steel pier into the foundation and consists of steel pier with PBL and socket steel pipe. Main reinforcements of the foundation are arranged and in situ concrete is filled between the steel pier and socket steel pipe and inside of steel pier. The socket anchoring system can expectedly reduce the cost and construction period by omitting anchor frame which is used for traditional anchor system. Figure 3 shows the general drawing of pier AP3 using socket anchoring system. As shown in the section of the superstructure in Figure 3, we adopt rigid connection of new and existing concrete slab, and remove longitudinal joint from the viewpoint of easy maintenance, running comfortability. Therefore new pier foundation has to be placed in the same section of the existing pier foundation, and also connected rigidly with it. However, if we place in the same section of the existing pier foundation, the AP3 pier is interfered underground installation, waterway and road, and AP3 pier foundation is limited in its structural size (Figure 4) Pier AP3 Existing pier Figure 3 General drawing of pier AP3 2415 2600 10 00 50 0