Finger Joint Bridging Cover Plate for Bridge Expansion
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Solution Overview
Problem
Conventional finger joint devices face challenges in structural stability, economic efficiency, and handling difficulties due to thick iron plates required for large expansion and contraction gaps in bridges, especially in medium-length, long, or super-long bridges, and are prone to damage during earthquakes.
Innovation Solution
A finger joint system comprising a bridging cover plate supported by both structures, with a first finger unit and a second finger unit allowing relative movement, and an elastic pressing mechanism to reduce plate thickness and enhance stability, enabling transverse displacement and movement in various directions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the thickness of iron plate is increased to handle large expansion and contraction gaps, then structural stability is improved, but handling difficulty and manufacturing complexity increase significantly
Solution Approach 1:
The expansion joint device is divided into multiple finger units (first finger unit and second finger unit) with multiple fingers each, allowing the structure to accommodate large gaps through the collective action of multiple thinner elements rather than requiring a single thick plate
Solution Approach 2:
The invention transitions from a single thick plate solution to a multi-finger arrangement that distributes the structural requirement across multiple dimensions and elements, enabling the use of thinner, more manageable steel plates while maintaining overall structural stability
2Strength
If the thickness of iron plate is increased to support large expansion and contraction gaps, then load-bearing capacity is improved, but manufacturing complexity increases
Solution Approach 1:
The load-bearing function is distributed across multiple fingers in the first finger unit and second finger unit, each made from thinner, more easily manufactured steel plates, eliminating the need to cut and smooth extremely thick plates
Solution Approach 2:
The finger units are designed to move relative to each other dynamically, allowing thinner plates to achieve the required load-bearing capacity through mechanical advantage and distributed stress rather than relying solely on plate thickness
3Adaptability or versatility
If the interval between abutment points is increased to accommodate large expansion and contraction, then the finger joint can handle larger gaps, but the required finger thickness becomes excessively large
Solution Approach 1:
The expansion joint is segmented into multiple fingers within each finger unit, allowing the system to accommodate large gaps through the combined effect of multiple elements rather than requiring a single excessively thick finger
Solution Approach 2:
The bridging cover plate acts as an intermediary element that spans across the gap between structures, working in conjunction with the finger units to distribute loads and enable the use of thinner fingers while maintaining gap accommodation capability
Data Source
AI summary
A finger joint having a bridging cover plate, which enables a steel plate having a thickness much smaller than that of a conventional finger to be used and allows the vertical rotation of an upper bridge structure. The finger joint includes: a bridging cover plate installed on a first structure and supported to a second structure across a gap so as to support a load of a vehicle passing over the gap, and configured to allow relative movement between the first structure and the second structure in a direction in which the distance of the gap changes; a first finger unit connected to the bridging cover plate; and a second finger unit installed on the second structure so as to allow relative movement relative to the first finger unit in a direction in which the distance of the gap changes.