Bridge Steel Support

Bridge steel support is a steel support system used for temporary load-bearing, stabilizing structures, or auxiliary forming during bridge construction. It is widely used in the construction process of bridge foundations, substructures (such as piers and abutments), and superstructures (such as beams and bridge decks). Through the high strength and stiffness of steel, the safety and stability of the structure during construction are ensured, providing reliable guarantees for concrete pouring, component assembly, and other operations.

Main types and application scenarios

According to the different construction sites and functions of bridges, bridge steel supports can be divided into various types, including:

1. Foundation and substructure steel support

Application scenario: Mainly used for the construction of bridge pile foundations, abutments, and piers, such as cofferdam support for deep water foundations and lateral support for pier templates.

Typical form:

Cofferdam support: In the construction of underwater bridge piers, the internal support of steel cofferdams (such as double walled steel cofferdams) often uses steel sections (such as H-beams, I-beams) or steel pipes to resist water pressure and soil pressure, ensure the stability of the cofferdam structure, and prevent deformation.

Pier formwork support: during pier pouring, steel slant support or circumferential steel support shall be set outside the steel formwork to control the perpendicularity and section size of the formwork and avoid formwork expansion and deviation due to lateral pressure during concrete pouring.

2. Steel support for upper structure

Application scenarios: Suitable for beam prefabrication, cast-in-place (such as continuous beams, cantilever beams), and bridge deck construction. Its core function is to bear the self weight of the beam, construction loads, and control structural deformation.

Typical form:

Support method for construction: In the construction of cast-in-place beams, full span steel supports (such as plate buckle steel pipe supports and portal steel supports) are commonly used vertical support systems. They form a grid structure through upright, horizontal, and diagonal bars to evenly transmit beam loads to the foundation, and are suitable for bridges with small spans.

Cantilever construction support: In the cantilever pouring construction of large-span continuous beams and rigid frame bridges, the load-bearing structure of the hanging basket (such as steel truss, steel sling) is essentially a type of steel support, used to suspend the formwork and pouring concrete, while bearing the bending moment and shear force during the construction process.

Temporary support for prefabricated beams: After the prefabricated beams are hoisted into place, temporary steel supports (such as adjustable steel piers) need to be set up to adjust the elevation of the beam body. After the installation of the supports or the pouring of wet joints is completed, they should be removed to ensure the stability of the beam body during the construction phase.

Core features and advantages

Strong bearing capacity: Steel has much higher tensile and compressive strength than materials such as wood and concrete, and can adapt to larger loads during bridge construction (such as the self weight of large-span beams and heavy construction machinery loads), ensuring structural safety.

High stiffness and small deformation: Steel supports have a high elastic modulus and small deformation under load, which can effectively control the construction accuracy of bridge structures (such as beam elevation and axis deviation) and reduce the workload of later leveling and repair.

Adjustable and flexible: Most bridge steel supports (such as adjustable piers and top supports) are designed with height adjustment functions, which can adapt to the needs of elevation adjustment during construction, especially suitable for scenarios with complex terrain or variable structural dimensions.

Convenient disassembly and assembly, good turnover: Steel components are mostly designed with standardization, and can be quickly assembled or removed through bolts, pins, and other connecting parts. They are wear-resistant and not easily damaged, and can be reused multiple times in different bridge projects, reducing long-term construction costs.

Wide adaptability: Whether in land, water or high-altitude work scenarios (such as construction platform support for suspension bridges and cable-stayed bridges), steel supports can meet the stress requirements of different environments through reasonable design, and their applicability is far superior to traditional support materials.

Design and construction precautions

Accurate force calculation: It is necessary to determine the cross-sectional dimensions, spacing, and connection methods of steel supports through structural mechanics calculations based on parameters such as bridge structure form, construction load, span, and geological conditions, to ensure that their strength, stiffness, and stability meet regulatory requirements and avoid collapse accidents caused by insufficient support.

Reliable foundation treatment: A solid foundation (such as concrete cushion or steel pad) should be set up at the bottom of the steel support to disperse load pressure and prevent foundation settlement from causing support instability. Especially in soft soil foundation or water construction, foundation reinforcement (such as pile foundation) needs to be strengthened.

Secure connection nodes: Steel supported nodes (such as the connection between uprights and crossbars, and the contact points between supports and structures) need to use high-strength connectors to ensure effective force transmission and avoid structural deformation caused by node loosening and sliding.

Dynamic monitoring in place: During construction, real-time monitoring of settlement, displacement, stress and other indicators of steel supports is required (such as using total stations and stress sensors). Once abnormalities are detected (such as deformation exceeding specifications), reinforcement measures should be taken immediately to prevent the accident from escalating.