1. Project Overview
The Bayou Bridge, also known as the Wantou Bridge, is a key urban road in Ningbo City, located on the eastern side of Sanjiangkou in Yaojiang Bay (see Figure 1). This bridge serves as a vital transportation link, connecting different parts of the city with its impressive design. The main bridge is a three-span continuous steel truss arch bridge with a total span of 48m + 180m + 48m = 276m. It has a width of 43.6 meters, making it a prominent structure in the area. The arch rib of the main bridge consists of two trusses and six wind braces, with a lateral center spacing of 33.6 meters between the two arch ribs. At the arch's apex, the vertical distance between the upper and lower chords is 4.5 meters. The lower chord follows a quadratic parabola with a rise of 36 meters and a span ratio of 1:5, while the upper chord combines a quadratic parabola with a circular curve for enhanced structural performance. The primary materials used in the bridge’s construction are Q370qE and Q345qD steel, with a total steel volume of approximately 7,700 tons. This combination of materials ensures high strength and durability, suitable for the demanding conditions of a large-scale bridge project.
Figure 1: Wantou Bridge Real Scene
2. Construction Challenges
One of the main challenges in this project was the welding of thick plates, particularly the box-type edge fittings of the steel arch ribs and the angular welds of the main beams. All these joints required full penetration welding to meet the structural requirements. Due to the varying positions and loads along the bridge, each section of the arch ribs and rib cages had to be carefully designed and welded to ensure integrity and safety. With a large number of penetration welds involved, maintaining consistent and high-quality welding became a critical aspect of the project. The complexity of the joint configurations and the thickness of the materials made this task even more challenging. Ensuring that every weld met the required standards was essential to the success of the entire structure.3. Welding Joint Qualification Standards
To guarantee the quality and reliability of the welded joints, strict standards were set. The yield strength, tensile strength, elongation after fracture, and low-temperature impact absorption energy of the welded joints must not be lower than those of the base metal (as shown in Table 1). Additionally, the maximum hardness (HV10) in the three zones of the welded joint should not exceed 350HV. Another important requirement is that the butt joints must be able to withstand a cold bend of 180° without cracking. These criteria ensure that the welded joints are not only strong but also ductile and resistant to brittle failure under various environmental conditions. For more detailed information, please refer to the attached documents or read the 18th issue of Metalworking (Hot Processing).Solar Street Light,Led Street Light,Led Street Garden Lamp,High Power Led Street Light
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