Key welding technology of Harbin Matsuura Bridge
I. Project Overview
The Harbin Trans-Songhuajiang Songpu Bridge is a single-tower double cable-stayed cable-stayed steel bridge in the northeastern high-altitude region of China (see Figure 1). The main span of the steel beam is 268m, the side span is 208m, the total length is 476m, and the full width of the bridge deck is 39.3m. The total weight is about 7000t. The steel beam of the bridge is composed of a main longitudinal beam, a beam, a small longitudinal beam and two side beams, wherein the main longitudinal beam is a box-shaped section, and the outer belly plate is welded with a anchor box. Except for the box-shaped section of the beam at the auxiliary pier, the other beams are of the working section. The small longitudinal beams and the pick-up beams are welded with an I-shaped cross section. Shear nails are welded to the main stringers, beams, and small stringers. The connection between steel beams is mainly in the form of bolting, in which LZ0～LB0, LB14～LB19 main longitudinal beam is full-section welding, some beams (HL3, HL10), and the connecting beam and main longitudinal beam are welded.
36 pairs of steel anchor beams are arranged in the bridge tower, and the steel anchor beam is constructed as shown in Fig. 2. Each pair of steel anchor beams is 4.5m long, weighs 6.98~8.86t, and the total weight is about 270t. The main structure of the bridge adopts Q345qE and Q370qE steel plates with a thickness of 10~50mm.
Second, the difficulty of welding
In the steel structure manufacturing process of Songpu Bridge, the following welding difficulties exist:
(1) The Songpu Bridge has a novel structure. The main longitudinal beam adopts a large-section box structure and a cable-stayed anchor box. All of the factory is made of welding. The welding space of the anchor box and steel anchor beam is small, and most of them are I. Grade penetration welds are difficult to weld.
(2) The main materials are Q345qE and Q370qE steel plates, which require a welded joint of -40 °C low-temperature impact absorption energy ≥ 34J, and the joint toughness standard is high.
(3) Due to the large section size of the steel box girder of the main bridge, the large longitudinal steel plate, anchor box, steel anchor beam and other components with large force are large (50 mm maximum), so the welding deformation is large.
(4) The main longitudinal beam, beam and cable tower are mainly bolted at the site, the installation accuracy is high, and the control requirements for box welding deformation are strict. LZ0～LB0, LB14～LB19 main longitudinal beam is welded to the whole section of the construction site, and the welding technology is difficult.
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