Views: 221 Author: Site Editor Publish Time: 2024-11-18 Origin: Site
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● Steel Truss Bridge Advantages and Characteristics
A steel truss bridge, especially the Bailey truss bridge, is a significant form of bridge structure. Its main truss is connected by pins. The structure includes top chords, bottom chords, and web members. The web members can further comprise various components. For instance, in a patent for prefabricated steel bridges obtained by Xingtu, the web members include first and second members. The first member is rotatably connected at both ends to the top and bottom chords, while the second member is connected at one end to the bottom chord and at the other end to the top chord or the first member, with a detachable connection. The first member, second member, and top or bottom chord can form triangular or rhombic structures, or a trapezoidal structure with the addition of the fourth member. When the second member is removed, the top and bottom chords move closer together.
Bridge Design Review: Evaluate the bridge design to ensure structural safety and construction feasibility.
Land Preparation: Ensure the construction site is level and properly drained to avoid water-related issues during construction.
Equipment and Material Preparation: Prepare necessary construction equipment (e.g., cranes, lifting gear, welding machines) and materials (e.g., bridge decks, support materials).
Personnel Allocation: Reasonably arrange working hours and task assignments for construction personnel to ensure smooth progress.
Foundation Construction: Excavate foundation pits on both sides of the bridge and pour and cure the foundations to ensure load-bearing capacity and stability.
Pier Construction: Construct piers on the foundations according to design requirements, including steel installation, concrete pouring, and curing.
Deck Installation: Install the deck of the steel truss bridge on the piers according to design drawings, using cranes to ensure accurate installation.
Support Structure Installation: Install support structures at both ends of the bridge and between piers to enhance stability and load-bearing capacity.
Steel Truss Lifting: Use cranes to lift and install the steel truss onto the piers and support structures, ensuring accurate installation and fixation.
Deck Paving: Lay the deck on the steel truss, typically using asphalt concrete or reinforced concrete paving.
Final Adjustment and Inspection: Adjust and inspect the completed steel truss bridge to ensure it meets design requirements for levelness and verticality.
Structural Inspection: Conduct a structural inspection of the completed steel truss bridge, including inspections of piers, steel trusses, and decks.
Structural and Mechanical Characteristics
Thin-walled Structure: To improve sectional efficiency, steel truss bridges are generally designed as thin-walled structures. Stress calculations should consider shear lag, torsion (free and restrained), and warping effects.
Stability Issues: Steel truss bridges have low structural stiffness and prominent stability issues. As thin-walled structures, stiffeners and limitations on plate width-to-thickness ratios are required to prevent local buckling of plate elements.
Stiffness Requirements: Due to their low stiffness, designs must ensure bridge stiffness by limiting the slenderness ratio of members, deflection, and the width-to-span ratio of the steel bridge.
Fatigue Factors: The fatigue strength of components and connections is influenced by material quality, connection methods and types, load nature, stress state, stress amplitude, and stress ratio.
Connection Methods: Steel truss bridge components are generally welded from steel plates and steel sections and assembled using bolts (high-strength bolts) or field welding.
