Rebar Splice Joint for Thermal Movement Across Concrete Slabs
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Solution Overview
Problem
Existing concrete floor constructions with expansion joints between adjacent slabs are inefficient and prone to damage from thermal expansion and contraction, requiring additional structural support and time-consuming construction processes.
Innovation Solution
A splice device with bores and a cavity that accommodates rebar movement due to thermal expansion and contraction, using a fill material to securely connect rebar from adjacent slabs, eliminating the need for expansion joints.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If expansion joints are used to separate adjacent concrete slabs, then thermal expansion and contraction can be accommodated, but structural stability is reduced and additional structural support is required
Solution Approach 1:
The splice device acts as an intermediary component between adjacent concrete slabs, providing a mechanism to accommodate thermal expansion and contraction while maintaining structural continuity. The device includes a cavity that allows rebar to move freely in response to thermal changes, while the fill material provides bonding to maintain structural integrity, thus mediating between the need for movement and structural stability.
Solution Approach 2:
The splice device incorporates dynamic characteristics by allowing the rebar to move freely within the cavity in response to thermal expansion and contraction. This dynamic capability enables the structure to adapt to temperature changes without compromising overall structural stability, as the rebar can expand and contract within the confined space of the cavity.
2Adaptability or versatility
If expansion joints with gaps are used between slabs, then thermal movement can be accommodated, but construction time increases due to additional support requirements
Solution Approach 1:
The splice device merges multiple functions into a single component: it provides thermal expansion accommodation, structural connection, and grout filling all in one element. By integrating these functions, the device eliminates the need for separate expansion joint components and additional structural supports, thereby reducing construction time while maintaining thermal movement capability.
Solution Approach 2:
The splice device is a multi-functional component that simultaneously accommodates thermal expansion, provides structural connection between slabs, and serves as a conduit for grout filling. This universality allows it to replace traditional expansion joints that required multiple separate components and steps, streamlining the construction process.
3Stability of the object's composition
If rebar is rigidly connected between slabs, then structural stability is improved, but thermal expansion causes damage
Solution Approach 1:
The splice device introduces dynamic characteristics into the rebar connection by allowing free movement within the cavity. This enables the rebar to expand and contract with temperature changes without generating damaging stresses, while the fill material maintains structural bonding. The dynamic design prevents thermal expansion damage while preserving structural stability.
Solution Approach 2:
The splice device changes the physical state of the rebar connection from rigid to semi-rigid by allowing movement within the cavity. The rebar transitions between fixed and movable states depending on thermal conditions, enabling it to accommodate temperature changes while maintaining structural integrity through the bonding effect of the fill material.
4Adaptability or versatility
If a cavity is provided for rebar movement, then thermal expansion is accommodated, but device complexity increases
Solution Approach 1:
The splice device segments the rebar connection into two functional zones: a cavity region that allows free movement for thermal expansion, and a bonded region where the fill material provides structural connection. This segmentation enables the device to accommodate thermal movement while maintaining structural integrity, and the modular design simplifies installation.
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
Enhances structural stability and reduces construction time by allowing rebar from adjacent slabs to be connected without expansion joints, accommodating thermal movements until the building's thermal envelope is stable.
Implementation Method 1
in response to the fill material curing in the cavity, the fill material and the portion of the second rebar are secured in the cavity and connect the device to the second rebar
Implementation Method 2
This movement has two components, both related to thermal expansion caused by ambient air temperature increasing in the environment
Data Source
AI summary
A splice device and method for connecting reinforcing bars across adjacent concrete slabs in floor construction. The device includes a cylindrical body extending along a longitudinal axis with a threaded bore at a first end for fixedly attaching to a first rebar and a slot-shaped opening at a second end for receiving a second rebar. The slot opening permits both axial and lateral movement of the second rebar during construction. The device accommodates thermal expansion and contraction of the concrete slabs and structural frame during construction by allowing the second rebar to move within the cavity while maintaining a gap distance from the threaded end. After the building thermal envelope is completed and interior temperatures stabilize, the cavity is filled with a curable fill material through the inlet, which upon curing securely fixes the second rebar and structurally couples the adjacent concrete slabs.