A hinge bridge, often specifically referring to a hinged arch bridge, is a type of bridge structure that incorporates hinges into its design to accommodate movement.
Understanding Hinge Bridges
In structural engineering, bridges are subjected to various forces and movements, including expansion and contraction due to temperature changes, settling of supports, and deflection under load. To manage these movements effectively and prevent excessive stress, engineers sometimes incorporate hinges.
According to the provided reference, a hinged arch bridge is one with hinges incorporated into its structure to allow movement. These hinges are not like door hinges; instead, they function as specific points within the bridge structure designed to permit rotation or slight changes in angle without transferring bending moments.
The Role of Hinges in Bridge Design
The inclusion of hinges serves several key purposes:
- Accommodating Thermal Expansion/Contraction: Materials expand in heat and contract in cold. Hinges allow the bridge structure to adjust subtly to these changes without building up internal stresses.
- Managing Settlement: If the bridge supports settle unevenly, hinges can help distribute forces and prevent cracking or damage.
- Simplifying Structural Analysis: Adding hinges can turn a statically indeterminate structure into a statically determinate one, which simplifies the calculation of forces and stresses during the design phase.
What is a Hinge in this Context?
The reference defines a structural hinge as essentially a "cut in the structure" that is designed to withstand compressive forces but allows rotational movement. It acts as a pivot point. Common types of hinged arch bridges include two-hinged and three-hinged arches, referring to the number of hinge locations.
| Feature | Description |
|---|---|
| Core Purpose | Allows structural movement (rotation) |
| Construction | A "cut in the structure" at specific points |
| Primary Force | Can withstand compressive forces |
| Benefit | Manages thermal changes, settlement, simplifies analysis |
| Type Example | Often found in hinged arch bridges (two-hinged, three-hinged) |
By allowing controlled movement at specific points, hinge bridges can be more resilient to environmental factors and foundational shifts, ensuring the long-term durability and safety of the structure.
