Issue 47

Y. Mizuno et alii, Frattura ed Integrità Strutturale, 47 (2019) 209-220; DOI: 10.3221/IGF-ESIS.47.16 216 Horizontal Rotation Method (Fig. 11) Kingsgate Bridge is a pedestrian bridge over the River Wear that Ove Arup regarded as his life’s masterpiece. As explain earlier, V-shaped half parts, rigid frame pier and beam, were constructed on cylindrical foundations parallel to the river. The parts were then rotated by 90° and connected. During construction, the two V-shaped structures functioned as a cantilever truss system. Then, the final structural form took shape through rotation-z on the cylindrical foundation. The extremely slender V-shaped pier gives the bridge an elegant and delicate appearance. Figure 11: Horizontal rotation method (Kingsgate Bridge [1]) . Vertical Cable Erection Method (Fig. 12) In this method, two types of suspension cables are employed in the construction state. Carrier cables transport blocks of bridge members and main cables hang vertically. After the truss bridge (the final structure) is completed, hanger ropes are removed and the dead load is transferred from a suspension system to a diagonal system––the truss system. This method requires many temporary structures, such as pylons, carrier cables, and main cables; however, there are many variations of structural forms in the completed state because the main cables work as falsework, taking all loads. Figure 12: Vertical cable erection method [9] . Reinforcement by Retrofitting the Middle Hinge PC Bridge with String Beam Structure (Fig. 13) The rigid-frame middle hinge bridges, which were constructed frequently during the period of high economic growth in Japan, has a striking deflection at the hinge located in middle of the span. Therefore, this method was used for restoring it. The bending moment at the hinge point is zero and the floor construction beam overhangs both endpoints beyond the