Extradosed and cable-stayed bridges, exploring the boundaries

Abstract

The extradosed bridge can be thought of as intermediate between the girder and cable-stayed bridge forms. This paper explores the boundaries of this form of bridge to attempt to define them more clearly. The paper summarises previous work on extradosed bridges and outlines the authors' own findings from their parametric study of a bridge near the boundary between cable-stayed and extradosed. The key parameters of extradosed bridges are outlined and compared with those for girder and cable-stayed bridges. The study indicates that although there is a clear division between girder and extradosed bridges the boundary, if any, between extradosed and cable-stayed forms is less clear.

Extradosed Bridges in Poland—Design and Construction

“…A similar diagram is presented in Figure 10 illustrating the relationship between the height of pylon H and the span L for extradosed and cable-stayed bridges (Collings and Gonzalez, 2013), including data collected on Polish structures. This diagram shows another feature distinguishing extradosed bridges-low pylons.…”

“…Figure 9 shows relationship between the deck depth D (at the tower support) and the span length L for those types of bridges built worldwide (Collings and Gonzalez, 2013). The extradosed bridges built in Poland, summarized in Table 1, have been additionally placed on the diagram.…”

“…Figure 11 presents span to tower height ratio (L/H) versus tower height to girder depth ratio (H/D) for cable-stayed and extradosed bridges built worldwide (Collings and Gonzalez, 2013) and in Poland. It is evident that the extradosed bridges have similar H/D ratio and similar L/H ratio.…”

“…The first such structure was the Odawara Blueway bridge, which was designed and constructed in Japan (Shirono et al, 1993). The extradosed bridge can be defined as the structure being between the girder bridge and the cable-stayed bridge (Mermigas, 2008;Collings and Gonzalez, 2013). The key feature visually distinguishing the extradosed bridge from the cable-stayed bridge is the low tower height above the deck and hence shallow stay angles.…”

Editorial

“…It is also again a truly international issue with papers coming from four different countries. In the first article Collings and Gonzalez (2013) look at the similarities and differences between extradosed and girder as well as cable-stayed bridges. They attempt to define the concept of extradosed bridges more clearly and to that end show parametric studies on the basis of numerous project data.…”