UHPC Composite Beam Mounting Method for Cable-Stayed Bridge
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The construction of double-sided steel box UHPC composite beam cable-stayed bridges faces challenges due to significant deformation and stress issues during the assembly of main beams, leading to difficulties in matching and welding, and potential damage to the bridge deck.
Innovation Solution
A mounting method that includes prestressed tensioning in the transverse direction of the bridge for all beam segments, initial tensioning of stay cables, and precise matching and welding techniques to reduce deformation and stress, ensuring accurate alignment and assembly of the main beams.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional supporting bases are used for matching connection, then the connection can be made when deformation is small, but when the matching height difference exceeds 5 cm, the connection becomes impossible and local stress becomes too large
Solution Approach 1:
The patent applies preliminary action by tensioning the stay cable of the beam segment to be connected before the hoisting process begins. This pre-tensioning creates a preliminary counteracting force that reduces the deformation of the transverse beam web during hoisting, thereby controlling the matching height difference to remain within 3 cm and enabling successful connection without excessive local stress
Solution Approach 2:
The patent changes the parameter of cable tension force dynamically during the construction process. By adjusting the tension force of the stay cable from initial tensioning during hoisting to final tensioning after connection, the system controls the deformation of the beam segment and maintains the matching height difference within acceptable limits throughout different construction stages
2Ease of operation
If the bridge deck crane hoists the beam segment to be mounted, then the beam segment can be positioned, but the self-weight of the beam segment and crane cause downward deflection and reverse upward deflection resulting in large matching height difference
Solution Approach 1:
The patent applies preliminary anti-action by tensioning the stay cable before hoisting to create a counteracting force against the downward deflection caused by the beam segment's self-weight and crane load. This pre-established counterforce prevents excessive deformation during the positioning process, ensuring the matching height difference remains controllable
Solution Approach 2:
The patent performs preliminary action by establishing the stay cable tension system before the hoisting operation begins. This preliminary setup ensures that the counteracting force is already in place to mitigate the deformation effects during beam segment positioning, rather than attempting to correct large deviations after positioning
3Manufacturing precision
If stay cable is tensioned for the first time in advance as in wide PK composite box beam, then transverse deformation can be reduced, but the stiffness of transverse beam web in double-sided steel box is too small and deformation remains too large
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the tension force of the stay cable throughout the construction process. The tension force is increased from initial tensioning during hoisting to final tensioning after connection, adapting to the changing structural conditions and the inherently low stiffness of the transverse beam web in double-sided steel box structures
Solution Approach 2:
The patent uses preliminary action by tensioning the stay cable before hoisting to establish a counteracting force that compensates for the low stiffness of the transverse beam web. This pre-tensioning prevents excessive transverse deformation during the critical hoisting and connection phases
4Ease of operation
If bridge deck crane presses on connected beam segment during hoisting, then beam segment to be mounted can be lifted, but connected beam segment experiences large deformation and potential damage
Solution Approach 1:
The patent applies preliminary anti-action by tensioning the stay cable of the connected beam segment before hoisting begins. This creates a preliminary counteracting force that supports the connected beam segment against the downward pressure from the crane, preventing excessive deformation and potential damage while still allowing the lifting operation to proceed
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 method effectively reduces the faulting of slab ends, improves assembly quality, minimizes the need for surcharge loading measures, and prevents damage to the bridge deck by controlling deformation and stress within acceptable limits.
Implementation Method 1
initially tensioning a stay cable after the resting is completed
Implementation Method 2
the self-weight of the beam segment and the weight of the bridge deck crane will be transferred to front and rear anchor points
Implementation Method 3
lifting a beam segment to be mounted
Implementation Method 4
although the bridge deck is made of the ultra-high-performance concrete (UHPC) material, the bridge deck has a relatively large tensile stress in this hoisting condition
Data Source
AI summary
Provided is a mounting method of a main beam of a double-sided steel box UHPC composite beam cable-stayed bridge and a composite beam thereof. The method includes the following steps: carrying out prestressed tensioning in a transverse direction of the bridge for all beam segments; pouring UHPC when a wet joint between a second beam segment and a third beam segment located in front of an end beam segment is in a pre-bending state; initially matching and positioning the end beam segment and a beam segment to be mounted; tensioning a n-th stay cable corresponding to the end beam segment for the first time; tensioning the n-th stay cable for the second time to a designed cable force.