Control of Steel Pipe Arch

Tube concrete arch bridge, focuses on the processing and control requirements of the steel tubular arch rib, and is intended to provide a reference for the construction of similar bridges.

Keywords: steel pipe Concrete Arch Bridge Construction Control

 

1 Introduction

 

Steel concrete structure is concrete filled steel pipe within the formation of a composite structure, both steel and concrete structure is characterized by the play of the mechanical properties of concrete and steel, and steel pipe hoop, greatly improving the structure of the anti- The pressure capacity and resistance to deformation. Pipe Concrete Tied Arch Bridge beautiful shape, structured by the power of science, economic rationality, in recent years has been widely used in highways, urban bridge construction. However, due to its high technical content, rigorous process, many processes, and construction is very difficult, therefore, conscientiously sum up such a bridge construction and management experience, and practical guidance on the future design, construction, management. South of the river bridge in this article, for example, to refer briefly to the manufacture of steel tubular arch rib and construction control.

 

2, Project Overview

 

South River Bridge is located in Liyang City, Jiangsu Province, the west side, cross Nanhe a large bridge on the highway for the newly-created state trunk road from Nanjing to Hangzhou, a total length of 659.44m technical standards: design load steam - over 20 hanging -120; deck net width of a net -2 x 15.25m; fairway grade five planning; clearance standard of 50.0 × 5.0m; seismic intensity is a basic intensity 7 °.

 

South River Bridge main span arch structure under the deck prestressed concrete tie bar, the use of rigid tie beam rigid arch, calculation span 126.28m, arch axis parabola, Sag 25.256m span ratio is 1:5. Rib dumbbell-shaped steel concrete, up and down the pipe diameter 110cm, steel pipe with the web wall thickness of 1.4cm, filled No. 40 micro-expansion of the concrete. The wind bracing using K-type, composed by the outside diameter of 110cm and 80cm steel pipe welding. The full-bridge a total of four arch ribs, six pairs of wind bracing, 38-film beams and 76 boom.

 

3, Steel Pipe Arch processing

 

3.1, the main process

 

Testing of raw materials → loft → material → segment assembly and the web of the assembly and welding of processing → → Pyrotechnics microbending → welding → boom relevant ministries (with) parts assembly → Exhaust → welding process detection, the row of the pulp holes to set up security → Rib pre-assembled → coating rust-proof.

 

3.2, the processing of program elements

 

Segment division: the ease of lifting the arch rib steel pipe segments produced. The bridge lifting capacity combined with field, every piece of Rib is divided into two arch foot embedded segment and 7 middle lifting segment K wind brace each for a period.

 

Production methods: rolling machine made of steel tube; assembly welding Rib tubes and the design of the basic length of about 6m and 17m wind bracing tube; the upper and lower arch rib pipe using the Pyrotechnics Microbend formed the design axis, subsequently set a special tire rack to complete the assembly of the positioning, welding and segments; the wind bracing pipe segments in another flat tire rack to complete assembly.

 

The joint margin and put: to meet the design requirements to ensure that each step of the construction program and process can achieve the required deviation of accuracy, the upper and lower arch rib pipe large joints and put a 80mm margin, the margin segment assembly when retained only in calculated in subparagraph length at make is for the line. Welding compensation plus put: considering the assembly of the segments, the web welding will make the distance of the arch rib section down tube affected, along the radial direction and put the 5mm as the welding compensation, to ensure that the design of geometric dimensions.

 

The tag line: marked Rib pipe 0 ℃ and 180 ℃ radial line segment assembly, inspection, fire workers, tag line.

 

Installation label: take certain protective measures to facilitate site installation, Rib pre-assembled before determination of the radial line with the station line indicate the control points of each connector at the installation site, make a mark, painting.

 

3.3, the construction control points

 

(1) provided in accordance with the design documents acceptance, process requirements, the preparation of the specific test items and standards of the various processes.

 

(2) loft should ensure that all supporting tables, nesting cards, the accuracy and completeness of the material sketch, indicating the model for follow-up process, the kind of rod angle, size, name, data.

 

(3) cutting of all the parts required to inspection, the ultra-poor parts shall not be into the next process; flame cutting parts have to slag, grinding, resulting in heat distortion must be corrected before.

 

(4) the degree and angle of bevel edge of a straight line should be consistent with the tolerance requirements.

 

(5) tooling tire rack should have sufficient stiffness to make the necessary tags to control the structural deformation, the response to the tire frame centerline, locating datum line, auxiliary lines.

 

(6) all the assembly shall not mandatory to avoid the damage of the parent material, strictly on the line to install and control the gap should be corrected in a timely manner after the completion of the weld.

 

(7) strictly control the Rib pipe Pyrotechnics temperature, Never use water to cool.

 

(8) Develop a thorough professional measurement technology, detection instrument shall be subject to measurement department inspection, consider the environmental impact of operations.

 

(9) and improve the safety and security measures.