Temporary Support Removal for Box Girder Bridges
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Solution Overview
Problem
The existing temporary support systems for road bridges with pre-fabricated small box girders have limited load-bearing capacity and restricted space, making it difficult to efficiently remove the support structures after construction, which hampers construction efficiency and transportation capacity.
Innovation Solution
A method involving the sequential removal of cantilever beams, lateral pier support systems, main beam sections, main truss systems, and main pier vertical support systems using specialized hoisting equipment and horizontal-displacement apparatuses, allowing for vertical and horizontal movement of components onto flatbed trucks, thereby overcoming the limitations of traditional cranes and improving space utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a traditional temporary support system with dense rod members is used to reduce main support pillar length ratio, then the overall stability of the bracket system is improved, but vehicles cannot pass through the support area during construction and removal
Solution Approach 1:
The support system is divided into modular components: main support pillars, lateral support pillars, and removable rod members. This segmentation allows selective removal of rod members to create vehicle passage paths while maintaining structural stability through the remaining pillar framework
Solution Approach 2:
The support system transitions from a static dense configuration to a dynamic reconfigurable structure. Rod members can be removed or repositioned during different construction phases, allowing vehicle passage when needed while providing full stability during load-bearing phases
2Productivity
If heavy-duty cranes are used to remove large-scale temporary support systems, then the removal capability is sufficient, but the equipment cannot operate in limited headway spaces
Solution Approach 1:
The support system is designed with segmented components that can be removed in smaller sections using lighter equipment. Main beam sections, lateral support pillars, and rod members can be detached and removed separately, enabling operation in limited spaces without requiring heavy-duty cranes
Solution Approach 2:
The removal process utilizes horizontal displacement along the bridge deck axis rather than vertical lifting only. Components are moved horizontally to extraction points where they can be loaded onto vehicles, allowing lighter equipment to handle larger components in constrained spaces
3Strength
If the support system is designed for PC hollow slab girder construction, then the load-bearing capacity is sufficient for that application, but it has limited load-bearing capacity for pre-fabricated small box girders which are more than three times heavier
Solution Approach 1:
The support system is designed as a universal framework that can accommodate different girder types and weights. The main support pillars, lateral support pillars, and rod members form a configurable structure that can be adjusted for PC hollow slab girders, pre-fabricated small box girders, and other bridge types through modular reconfiguration
Solution Approach 2:
The support system parameters (pillar spacing, rod member configuration, connection details) can be modified to match different load requirements. The same basic framework design can be adapted for lighter PC hollow slab girders or heavier pre-fabricated small box girders by adjusting the density and arrangement of support elements
Data Source
AI summary
A method for removal of a temporary support system for a road bridge pre-fabricated small box girder-type concealed bent cap, and equipment therefor. The removal method comprises the following steps: removing cantilever beams; removing lateral pier support systems and loading same onto a truck; removing outer-side main beam sections connected to lateral pier support systems and loading same onto a truck; removing, horizontally displacing, and lowering a main beam middle section connected to the main pier support system; hoisting, lowering, and laying flat a main truss system, and loading same onto a truck; and removing a main pier vertical support system and a pad beam.