Double U-Shaped Steel Composite Bridge Girder Design
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Solution Overview
Problem
Existing bridge construction methods are not suitable for multilane road/rail bridges due to obstructed traffic, high steel usage, and deep construction depths, which increase costs and construction time, and are not adaptable for longer spans.
Innovation Solution
A double U-shaped reinforced girder bridge and U-shaped composite reinforced girder approach made of I-section steel beams and slabs, where top and bottom U beams are connected with splices or HSFC bolts to form a full frame vierendeel type composite, reducing deflection and moments, and allowing for pre-fabrication and fast-track construction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If traditional in-situ construction methods are used for bridge girders, then the structure can be built for longer spans, but construction time increases and traffic obstruction occurs
Solution Approach 1:
The bridge structure is divided into modular components: precast concrete slabs, steel girders (I-section or box section), and standardized connection details. These segments can be manufactured separately and assembled quickly on-site, enabling long span bridges to be constructed without prolonged traffic obstruction.
Solution Approach 2:
Concrete slabs and steel girders are pre-manufactured in controlled environments before bridge construction. This preliminary fabrication allows quality control and parallel production, so that when components arrive at the site, assembly can proceed rapidly with minimal traffic disruption.
2Strength
If deeper girder construction is used to reduce steel usage, then structural efficiency improves, but construction depth increases and approach cost increases
Solution Approach 1:
The invention employs composite construction combining concrete slabs with steel girders (I-section or box section). The concrete slab acts as a compression element while the steel girder provides tensile strength and structural support. This composite system achieves high structural efficiency with reduced girder depth compared to pure steel or pure concrete constructions.
3Strength
If more steel is used to reduce construction depth, then structural strength improves, but weight increases and cost increases
Solution Approach 1:
By combining concrete and steel in a composite girder system, the structure utilizes the complementary properties of both materials: concrete provides compressive strength and durability, while steel provides tensile strength and structural rigidity. This optimized material combination reduces total steel weight compared to all-steel constructions while maintaining required structural strength.
Solution Approach 2:
The steel girder cross-section is optimized with varying thickness and reinforcement distribution based on local stress requirements. Web plates, flange plates, and stiffeners are dimensioned according to specific structural demands at different locations, minimizing steel weight while ensuring adequate strength throughout the structure.
4Stability of the object's composition
If elaborate formworks and bracing are used for in-situ construction, then structural stability during construction is ensured, but device complexity increases and construction time increases
Solution Approach 1:
The bridge is constructed by assembling pre-fabricated segments (concrete slabs and steel girders) with standardized connection details. This segmentation eliminates the need for complex temporary formworks and bracing systems required in traditional in-situ construction, as each component is self-supporting and designed for rapid assembly.
5Productivity
If precast construction is used to reduce construction time, then assembly speed improves, but transportation constraints limit box dimensions
Solution Approach 1:
The bridge superstructure is divided into manageable precast concrete slabs and steel girder components that can be transported using standard road and rail infrastructure. This segmentation allows rapid assembly of long span bridges without requiring oversized transportation capabilities, as individual components fit within standard transport dimensions.
Solution Approach 2:
The invention offers flexible cross-sectional configurations including I-section and box section steel girders. The box section provides enhanced structural efficiency for longer spans while maintaining transportable component dimensions, as the hollow section reduces self-weight without increasing external dimensions excessively.
Data Source
AI summary
A system for construction of double U and single U steel composite structure for bridges and methods thereof are disclosed. The system comprising: a base slab (1), a plurality of top and bottom U shaped beams (2, 8) made of I section, exterior top and bottom slabs (3, 9), a bottom deck slab (4), foot path (5) and kerb (6). In precast scheme U shaped bottom beams (2) are placed at about 2 m interval and exterior slab and bottom deck slab are casted. Top U beams are casted in inverted position. Base slab is provided and bottom U system is placed and top U system is provided over bottom U system forming a full frame vierendeel type composite as a self-straining unit. Earth filling compaction to be done. The approaches are made of single U section and being extended with I beam and RCC slab. Cast in situ scheme is done similar.