Tensioning Supporting Girders for Prefabricated Deck Compression
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Solution Overview
Problem
Current full-depth precast concrete deck systems require costly and time-consuming post-tensioning systems to provide pre-compression force across deck joints, which increases construction time and material usage.
Innovation Solution
The system achieves pre-compression across deck joints by tensioning the supporting girders themselves, eliminating the need for post-tensioning tendons and bars, and utilizing jacking frames to apply axial compression to prefabricated deck units.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If standard post-tensioning systems are used to provide pre-compression force across deck joints, then deck durability is improved, but construction cost and time increase
Solution Approach 1:
The invention extracts the post-tensioning tendons and bars from the system, eliminating the need for separate compression members. Instead, the girder itself is tensioned to provide the pre-compression force, removing the additional components and associated construction steps while maintaining the durability benefit
Solution Approach 2:
The invention merges the function of providing pre-compression force with the girder structure itself. By tensioning the girder, the same structural element that supports the deck also provides the compressive force across deck joints, combining two functions into one component and reducing construction complexity
2Reliability
If standard post-tensioning systems are used to provide pre-compression force across deck joints, then deck durability is improved, but construction cost increases
Solution Approach 1:
The invention removes the post-tensioning tendons, bars, and associated ducts from the system. By using the girder tensioning alone to provide pre-compression, it eliminates the additional materials required for separate post-tensioning systems while maintaining the necessary compressive force for deck durability
Solution Approach 2:
The girder is designed to serve multiple functions: it provides structural support for the deck and simultaneously generates the pre-compression force across deck joints through tensioning. This multi-functionality eliminates the need for separate post-tensioning materials, reducing overall material usage
3Productivity
If girder tensioning is used to produce pre-compression force, then construction cost and time are reduced, but the mechanism for applying compression must be simplified
Solution Approach 1:
The invention combines the girder structure with the compression application mechanism. By tensioning the girder itself to provide pre-compression, it eliminates the need for separate jacking devices and compression application systems, simplifying the overall mechanism while improving construction efficiency
Solution Approach 2:
The girder serves itself by providing both the structural support function and the compression application function. When the girder is tensioned, it automatically generates the pre-compression force needed at the deck joints without requiring external compression devices, making the system self-sufficient and simpler
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 approach reduces construction time and cost, enhances deck durability, and increases load resistance by directly tensioning the girders, thereby minimizing material requirements and construction complexity.
Implementation Method 1
The pre-compression force across deck joint is produced not by post-tensioning tendons but by tensioning the supporting girders themselves
Data Source
AI summary
A structural system comprised of prefabricated deck units spaced along longitudinal load-carrying members, which produce longitudinal axial compression in deck units by tensioning the longitudinal load-carrying members without the use of standard post-tensioning details. During construction, prefabricated deck units are erected on top of and supported by the longitudinal load-carrying members via leveling devices, which also permit relative motion between the longitudinal load-carrying members and the prefabricated deck units. Jacking apparatuses are used to introduce deck compression by jacking against the longitudinal load-carrying members. This system can be used for new structures and for deck replacement of existing structures.