콘크리트 충전 강관(CFST) 아치교 적용사례

21. 4. 19 오후 8:02

Arch Bridges are one of the oldest types of bridges and have great natural strength due to its geometry. Since the weight of arch bridges is carried outward along the curve, from the arch to the supports, they can be the perfect choice for long-span erections. Many new developments and improvisations on the design and construction of arch bridges have taken place in recent years, one such is the utilization of Concrete-Filled Steel Tubular (CFST) structures to arch bridges. This article will mainly focus on the use of CFST structures in arch bridges and some examples of CFST arch bridges in China.

 

 


 

Most Common Types of CFST Arch Bridges:

 

1. Deck arch bridges

2. Half through arch bridges

3. Through deck-stiffened arch bridges

4. Through rigid-frame tied-arch bridges

5. 'Fly-bird-type' arch bridges

 

 
Long Span arch bridges fig 1
 
Figure 1: Types of Arch Bridges
 

 

 

Benefits of CFST Arch Bridges:

 

1. The in-filled concrete helps delay the local buckling of steel tubes.

2. The steel tube reinforces the concrete in order to resist tensile stresses.

3. The steel tube improves the compressive strength of in-filled concrete.

4. The steel tube improves the ductility of in-filled concrete.

 

 


 

Erection Method:

 

Most CFST arch bridges are erected using the Cantilever method, Swing method, and Scaffolding method from which the Cantilever method and the Swing method are widely used as shown in the figures below. Firstly, Steel Tubular arches are erected and then concrete is pumped into the steel tubes to form the CFST arch ribs. Furthermore, both the main and auxiliary cables are used to maintain stability during the erection of arch ribs.

 
Long Span arch bridges fig 2Figure 2: Cantilever Erection Method
 
 
Long Span arch bridges fig 3
Figure 3: Swing Erection Method

 


 

CFST Deck Arch Bridges

 

In deck arch bridges, CFST ribs can be used either in vertical dumbbell ribs or as two vertical truss ribs connected by lateral bracing of steel tubes. The true arch CFST bridge has a great crossing capacity of almost 400m. An example of a CFST deck arch bridge is shown in the figure below.

 
Long Span arch bridges fig 4Figure 4: Baipanjiang Railway Bridge in China
  

 

CFST Half-Through True Arch Bridges

 

Half-through arch bridges are preferred when the rise of the arch bridge is much higher than the road elevation for the long span bridges. The world’s longest CFST arch bridge is the Wushan Yangtze River Bridge in China, with a main span of 460m as shown in Figure 5.

 
shutterstock_715184134Figure 5: Wushan Yangtze River Bridge in China
 
 

CFST Through Deck-Stiffened Arch Bridges

 

CFST through deck-stiffened arch bridges consist of CFST arch ribs and steel tied or prestressed concrete girders. The hangers are generally made of high-strength steel strands while the deck structure is made out of steel-composites or concrete, with cross beams and deck slabs. As the length of the span increases, construction challenges can increase since the horizontal reactions are not present until the tied girder is fully constructed.

 
Long Span arch bridges fig 6Figure 6: Hang-zhou Qian-jiang Bridge in China
 

 

CFST Through Rigid-Frame Tied-Arch Bridge

 

In CFST rigid-frame tied-arch bridges, rigid frame action is obtained by fixing the arch ribs to the piers; thereby, the arch rib can be erected similar to true arches using the cantilever cable-stayed method. For a large span bridge, temporary tied bars can be utilized whereas for a small span bridge the piers can withstand the thrust forces which arise due to the light self-weight of steel tubular arch rib. The construction of this type of bridge is less challenging than that of the tied arch with deck girder stiffened bridges.

 
shutterstock_1471322456
Figure 6: Hang-zhou Qian-jiang Bridge in China
 
 
 

CFST 'Fly-Bird-Type' Arch Bridges

 

These type of bridges generally consist of three spans wherein the two side spans are cantilevered half-arches and the central span is a half-through CFST arch. The main arch ribs and side arch ribs are fixed to the piers. Furthermore, prestressed-steel bars are anchored at the ends of the side spans to balance the arch thrust.

 
Long Span arch bridges fig 8Figure 8: Maochaojie Bridge in China
 
 

Overall, CFST arch bridges are an excellent choice for long-span erection bridges, and are recently being widely constructed due to their numerous advantages.

 

Here’s how an arch bridge could be designed through a bridge engineering software like Midas Civil.

 

 

 

References:

  • "New development of long-span CFST arch bridges in China." (2008). Chen, Baochun.

  • “Bridge Engineering Handbook.” Ed. Wai-Fah Chen and Lian Duan.

 

CIM 뉴스레터 구독

자세히 보기
Suman Dhara | Senior Bridge Engineer | MIDAS IT India

Suman pursued his Master's Degree in Structural Engineering from IIT Hyderabad, and has 6+ years of extensive experience in Technical Reviewing and Consulting for Bridge & Building projects. He enjoys providing solutions to engineers around the world on sophisticated projects ranging from bridge engineering, building engineering, and mechanics problems. 

Comments
자료다운로드 midas CIM
적용사례 및 제품소개

midas CIM을 활용한 토목분야 BIM Application 및
분야별 주요 기능을 확인할 수 있습니다.

자세히 보기