桥梁工程 英文文献1

桥梁工程 英文文献

A new way to design suspenders for through and half-through arch bridges

R.J. Jiang, Y.Y. Chen, Q.M. Wu, W.M. Gai and D.M. Peng

Shenzhen Municipal Design & Research Institute, Shenzhen, China

ABSTRACT: It is well-known that, in through and half-through arch bridges, the suspenders are important components since they connect the bridge deck to the arch ribs. The collapse of bridge deck or arch ribs may be induced once one or more suspenders are broken. In this paper, the traditional design way of the suspenders in through and half-through arch bridges is discussed first. Based on the discussion, a new way to design suspenders for arch bridges is then put forward. The reasonability of this new way is proved by numerical analysis examples. The impact effect of the remaining components of the arch bridge due to the breakage of one or more suspenders is obtained by appropriate simulation using the comprehensive commercial software ANSYS. It can be concluded from the analysis in this paper that the new way to design the suspenders for the through and half-through arch bridges can assure the safety of the bridge effectively even though one or more suspenders happen to break.1 INTRODUCTION

With the rapid development of new materials and construction technologies, the modern arch bridges are now entering a new era. The span length of the modern arch bridges is increasing, and the first two longest modern arch bridges are the Chaotianmen Yangtse River Bridge and the Lupu bridge, respectively. The Chaotianmen Yangtse River Bridge built in 2008 is a tied steel truss arch bridge with a span length of 552m; and the Lupu Bridge built in 2003 is a steel box arch bridge with a central span length of 550m. They are both half-through arch bridges and respectively located in Chongqing and Shanghai, China.

Arch bridges can be classified into three categories according to the relative positions between the deck and the arch: deck-arch bridge, half-through arch bridge and through arch bridge (Cheng J. et al. 2003). For both half-through arch bridge and through arch bridge, the suspenders are the important components since they connect the bridge deck with arch ribs and transfer kinds of loads from bridge deck to arches, and finally to foundation. However, at the same time they are the vulnerable members to be damaged or ruined, because they usually work both in formidable natural environment and under fatigue-induced cycling loads (Li D.S. et al. 2007). It is a fact that the service life of the suspender is much shorter than that of the arch bridge, and the suspenders must be replaced timely (Tang H.C. 2005).

The damage to the bridge deck or arches may be induced when one or more suspenders break, sometimes, even the collapse of the arch bridge may happen. In recent years, the accidents of arch bridges’ collapse caused severe casualties and huge economic loss (Li D.S. and Ou J.P. 2005 ). In order to know well about the health condition of suspenders, kinds of real time monitoring and diagnoses were conducted (Li D.S. et al. 2007). However, both the technologies and the materials for structural health monitoring and diagnose are not fully developed up to now (Li H.N. et al. 2008).

In this paper, the traditional design way of suspenders in through and half-through arch bridges is discussed first. Based on the discussion, a new way to design the suspenders in through and half-through modern arch bridges is then put forward. With the application of this new way, the arch bridge will remain safe even though one or more suspenders happen to break. This new design way is a different method from the health monitoring to control the safety of the modern arch bridges under the condition that the break of the suspender is uncontrollable. The reasonability and reliability of this new way is studied and proved by a numerical analysis example based on a real through arch bridge. The impact effect of the remaining components of the arch bridge due to the breakage of one or more suspenders is obtained by

桥梁工程 英文文献

R.J. Jiang, Y.Y. Chen, Q.M. Wu, etc. 263 appropriate simulation using the comprehensive commercial software ANSYS. It can be concluded from the analysis in this paper that the new way to design the suspenders in modern arch bridges can assure the safety of the bridge effectively even though one or more suspenders happen to break.

2 DISCCUSION ON TRADITONAL DESIGN OF ARCH BRIDGE SUSPENDERS

For through-type and half-through-type arch bridges, the suspenders are anchored to arch ribs at one end and transverse beams at the other. Generally speaking, in the traditional arch bridge design the double-suspender anchorage (Fig.1) instead of the single-suspender anchorage is widely adopted in order to keep the arch bridge still safe and make the replacement of the suspenders more convenient when one suspender happens to break.

S1

S2

A1=A2

θ1=θ2

S1=S2

However, the two suspenders at the same anchorage are usually designed as the same both in material and cross sections; i.e.,, E1=E2 , A1=A2 and θ1=θ2, where E, A and θ are the elastic modulus, cross section area and inclined angles of the suspender, respectively. That means they have the same or similar stress and variation of stress in service. They are also under the same or similar corrosion environment since they are located at the same anchorage. Hereby, it can be concluded that the two suspenders at the same anchorage will fail at the same or similar time because of the almost equal level of both fatigue load and corrosion environment.

Based on the discussion above, it can be seen that the double-suspender system designed in the traditional way will not improve both the safety of the arch bridge and the convenience of s …… 此处隐藏：21732字，全部文档内容请下载后查看。喜欢就下载吧 ……