Continuous Slab Track on Bridge Girders
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Solution Overview
Problem
The existing slab track systems on bridge structures require custom-made concrete slabs to match the length of bridge girders, leading to complex rail constructions and high costs, as well as the need for expansion joints that complicate the system.
Innovation Solution
A continuous concrete slab with a profiled concrete layer that slides on the bridge girder, independent of the girder's length, using a sliding layer and flexible materials to manage thermal expansions and avoid tension, allowing for a cost-effective and uninterrupted slab track system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the concrete slab length is adapted to match the bridge girder length, then the slab track can be firmly connected to the bridge structure, but special lengths of precast concrete slabs must be manufactured increasing cost and complexity
Solution Approach 1:
The system separates the concrete slab from the bridge girder connection through an intermediate profiled concrete layer. The concrete slab no longer needs to be directly connected to the bridge girder, allowing standardization of slab lengths independent of bridge girder variations.
Solution Approach 2:
A profiled concrete layer is introduced as an intermediary element between the concrete slab and the bridge girder. This intermediate layer absorbs the connection functions while allowing the concrete slab to maintain standard dimensions regardless of bridge girder length variations.
2Stability of the object's composition
If expansion joints are provided in the slab track to match bridge girder joints, then thermal expansion can be accommodated, but complex rail construction is required
Solution Approach 1:
The expansion joint requirements are extracted from the slab track system and relocated to the bridge girder level. The continuous profiled concrete layer and sliding mechanism allow the slab track to remain uninterrupted while the bridge structure handles its own expansion independently.
Solution Approach 2:
A sliding layer is introduced between the profiled concrete layer and the bridge girder, allowing dynamic movement to accommodate thermal expansion. This dynamic interface enables the slab track to remain continuous while adapting to bridge girder expansion and contraction.
3Strength
If the concrete slab is firmly connected to the bridge girder, then structural stability is improved, but thermal expansion differences cause impermissible tensions
Solution Approach 1:
The connection between the profiled concrete layer and the bridge girder is made dynamic through a sliding mechanism. This allows the system to maintain stability while accommodating differential thermal expansion between the concrete slab and the bridge girder structure.
Solution Approach 2:
The connection characteristics are changed from fixed to sliding, allowing the system to adapt to thermal parameter changes. The sliding layer enables relative movement that accommodates the different thermal expansion coefficients of concrete and steel bridge girders.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution enables the production of slab tracks that are independent of bridge girder lengths, reducing manufacturing costs and improving driving comfort by allowing continuous construction over bridges without interruptions and minimizing stress on the system.
Implementation Method 1
the concrete slab is exposed to much higher thermal expansion than the bridge girder itself due to the high mass of the bridge girder compared to the concrete slab and due to the direction of the heat radiation
Implementation Method 2
A sliding layer is arranged between the profiled concrete layer and the bridge girder, while the profiled concrete layer is firmly connected to the concrete slab of the slab track. In this way, the concrete slab and profiled concrete layer are allowed to slide on the bridge girder.
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The invention relates to a fixed running track (1) on a bridge structure, in which a concrete slab (3) is positioned on a bridge girder (2) to support a rail (6) for a rail vehicle. The concrete slab (3) forms a continuous strip that extends over at least two bridge girders (2). A continuous profiled concrete layer (7) is situated between the concrete slab (3) and the bridge girder (2). A running layer (10) is situated between the profiled concrete layer (7) and the bridge girder (2) and the profiled concrete layer (7) is permanently fixed to the concrete slab (3) of the fixed running track (1).