Self Adjusting Steel Bars for Concrete Expansion
Concrete structures face significant challenges from thermal expansion and shrinkage, with typical expansion coefficients of 10 × 10^-6/°C leading to dimensional changes that can compromise structural integrity. In large structures, these forces can generate internal stresses exceeding 5 MPa, resulting in cracking and potential failure points at rigid connections.
The fundamental challenge lies in developing reinforcement systems that can actively respond to dimensional changes while maintaining structural load capacity and bond strength between concrete and steel.
This page brings together solutions from recent research—including shape memory alloy integration for self-resetting capabilities, gradient expansion agents with internal curing mechanisms, and dynamic positioning systems for thermal stress distribution. These and other approaches focus on practical implementation strategies that can be integrated into existing construction methods while meeting building code requirements.
1. Reinforcement Belt Structure with Integrated Filling Expansion Concrete Section and Continuous Closing Mesh
CENTRAL AND SOUTHERN CHINA MUNICIPAL ENGINEERING DESIGN & RESEARCH INSTITUTE CO LTD, China Municipal Engineering Central-South Design and Research Institute Co., Ltd., 2024
Expansion reinforcement belt structure for super-long structures that eliminates the need for post-casting strips by integrating a filling expansion concrete section into the main reinforcement. The structure comprises a structural main reinforcement with a filling expansion concrete section cast in the middle, followed by shrinkage compensating concrete sections on both sides. A closing mesh connects the filling and shrinkage sections, providing a continuous reinforcement system that eliminates the need for post-casting strips while maintaining structural integrity.
2. Micro-Expansion Steel Tube Concrete with Gradient Expansion and Internal Curing Agents
CHINA RAILWAY MAJOR BRIDGE ENGINEERING GROUP CO LTD, 2024
Micro-expansion steel tube concrete with continuous expansion in steel tubes, featuring a gradient expansion agent and internal curing agent. The concrete achieves uniform expansion throughout the hydration process by incorporating a gradient expansion agent that continuously compensates for concrete shrinkage, while the internal curing agent provides continuous water supply for the expansion agent. This approach eliminates the conventional debonding issues associated with traditional expansion agents, resulting in a single-stage expansion process that maintains continuous contact between the concrete and steel tube walls.
3. Steel Structure Concrete Composite with Nickel-Titanium Copper Shape Memory Alloy Fiber Reinforcement
SHANGHAI CONSTRUCTION NO 1 GROUP CO LTD, 2023
A steel structure concrete composite that eliminates common construction challenges associated with pouring concrete into steel cavities. The composite comprises a hollow steel structure with a cavity, and concrete mixed with nickel-titanium copper shape memory alloy fibers that are uniformly distributed throughout the concrete. The concrete is poured into the cavity, forming a composite structure where the shape memory alloy fibers provide enhanced thermal and mechanical properties, enabling precise control over concrete curing and minimizing defects.
4. Steel Truss with Symmetrically Positioned Concrete Columns and Dynamic Positioning System for Thermal Stress Distribution
ZHAO ZHIANG, 2023
Concrete column steel truss design for high-temperature applications mitigates thermal stress-induced stress concentrations on steel columns. The truss comprises two identical concrete columns positioned symmetrically at the bottom of the steel truss. A specially designed positioning system between the columns and steel truss enables dynamic adjustment of the column's position during temperature fluctuations. This positioning system incorporates a self-adjusting mechanism that dynamically relocates the column's mounting points in response to thermal expansion and contraction, thereby distributing stress concentrations across the column.
5. Concrete Structure with Composite Wire Incorporating Activable Shape Memory Alloy for Localized Prestressing
THE BOARD OF TRUSTEES OF THE UNIVERSITY OF ILLLINOIS, 2023
Concrete products with localized prestressing capabilities achieved through an adaptive prestressing system. The system incorporates a composite wire with bonded wire segments that are constrained within the concrete body, with an activable central portion comprising a shape memory alloy wire segment that contracts upon heating to exert tensile force on the bonded segments. This localized prestressing is achieved through controlled deformation of the shape memory alloy wire segment during heating, allowing precise control over the prestressing force distribution within the concrete structure.
6. Reinforced Concrete Cast Body Structure with Fiber-Enhanced Expansion Section and Continuous Pouring Configuration
China Construction Second Engineering Bureau Ltd., THE SECOND CONSTRUCTION ENGINEERING COMPANY LTD, 2022
Raft expansion reinforced concrete cast body structure for buildings, particularly for symmetrical structures with temperature and dry shrinkage deformation. The structure comprises a pouring section, expansion reinforcement section, and a second pouring section. The expansion reinforcement section features a unique fiber arrangement with different hydration speeds, enabling controlled expansion forces during concrete formation. The pouring sections are designed with continuous pouring capabilities, utilizing a combination of pump grouping and oblique advancing to optimize expansion reinforcement placement. The structure incorporates a fiber swelling anti-cracking agent to prevent cracking during expansion.
7. Formwork System with Integrated Tensioning Element for Controlled Expansion Joints
FWR SOLUTIONS GMBH, 2022
A formwork system for expansion joints that enables controlled expansion of concrete sections without compromising structural integrity. The system incorporates a tensioning element that is integrated into the formwork panel itself, rather than being attached to the reinforcement. This tensioning element is designed to absorb the hydrostatic pressure of the concrete flow while maintaining precise control over the expansion movement. The tensioning element is strategically positioned to allow controlled expansion of the concrete sections while preventing rigid components from interfering with the joint's movement.
8. Reinforced Concrete Frame Joint with Integrated Shape Memory Alloy Elements
Dalian University, DALIAN UNIVERSITY, 2022
A self-resetting reinforced concrete frame joint that integrates shape memory alloy (SMA) elements into traditional reinforcement bars, enabling seismic performance enhancement while maintaining structural integrity. The SMA elements, comprising a shape memory alloy bar and a corresponding steel plate and nut, are integrated into the joint design to achieve self-resetting capabilities without compromising traditional reinforcement. This innovative approach enables the restoration of structural function after seismic events, while maintaining the performance characteristics of conventional reinforced concrete joints.
9. Continuous Expansion Reinforcement Belt with V-Shaped Groove Junction and Concrete Expansion Integration
CHINA FIRST METALLURGICAL GROUP CO LTD, 2022
A continuous expansion reinforcement belt for super-long structures that enhances waterproof performance and construction efficiency. The belt features a unique design where the expansion reinforcement part is bonded to the structural main reinforcement, with a V-shaped groove at the junction providing additional mechanical retention. The belt is constructed by pouring concrete with higher expansion rates on both sides of the reinforcement, creating a continuous joint that ensures reliable waterproofing. The belt's compact dimensions and precise reinforcement configuration enable efficient construction while maintaining superior performance.
10. Concrete Expansion Zone Structure with Integrated Reinforcement and Compensating Shrinkage Concrete
SINOHYDRO BUREAU 11 CO LTD, POWERCHINA 11TH BUREAU ENGINEERING CO LTD, PowerChina No. 11 Bureau Engineering Co., Ltd., 2021
Concrete expansion zone compensation structure for high-rise buildings that eliminates the traditional post-settlement pouring belt construction method. The structure comprises a concrete body with an expansion reinforcement belt and a compensating shrinkage concrete body arranged on both sides of the concrete body with an expansion reinforcement belt. Two layers of reinforcing steel members are integrated within the concrete body. The compensating concrete body provides additional support during shrinkage, while the expansion reinforcement belt enables continuous pouring without interruption. This innovative design eliminates the need for post-settlement joints and enables seamless construction of expansion zones.
11. Steel Bar Erection Piece with Elastic Ring Assembly and Protruding Metal Fins for Adaptive Expansion and Contraction
ANHUI FUHUANG CONSTRUCTION INDUSTRY CO LTD, Anhui Fuhuang Construction Industry Co., Ltd., 2021
A steel bar erection piece for prefabricated PC walls that enhances structural integrity through adaptive expansion and contraction. The piece comprises an inner and outer elastic ring assembly that integrates with the steel bar, with the outer ring featuring protruding metal fins. When the airbag expands, the assembly expands and contracts with the PC wall, eliminating the risk of leakage and internal stress. This design enables precise control over the steel bar's position within the concrete while maintaining structural integrity during thermal expansion and contraction.
12. Deformation Belt System with Embedded Strain Gauges and Telescopic Displacement for Concrete Structures
邢台职业技术学院, XINGTAI POLYTECHNIC COLLEGE, 2021
A deformation belt system for concrete structures that automatically releases restraint stress through controlled deformation of the concrete. The system comprises a deformation belt with embedded strain gauges, a single groove steel plate, a double groove steel plate, a telescopic displacement device, and a servo control device. The strain gauges are placed in the groove and monitor the deformation of the concrete. The servo control device generates expansion and contraction forces through the strain gauges, which control the opening and closing of the single groove steel plate. This controlled deformation effectively manages both axial restraint and temperature-induced deformation, while maintaining the structural integrity of the concrete.
13. Force Transmission Rod with Thermal Buffer and Self-Resetting Mechanism for Concrete Pavement Joints
Nanchang University, NANCHANG UNIVERSITY, 2021
Thermal-insulated self-resetting force transmission rod for concrete pavement joints that prevents cracking and deformation under temperature changes and wheel loads. The rod incorporates a thermal buffer layer that maintains optimal thermal conductivity between the rod and concrete, while its self-resetting mechanism ensures stable positioning even under dynamic loads. This design addresses the thermal stress concentration and displacement issues typically associated with force transmission rods in concrete pavement joints.
14. Steel Structure with Multi-Dimensional Multi-Layered Outer Wall Configuration Featuring Varied Protrusions
YUANZE LIU, Liu Yuanze, 2021
A construction steel structure that enhances thermal expansion and contraction resistance through a novel outer wall design. The structure incorporates a multi-dimensional, multi-layered outer wall configuration that incorporates multiple protrusions with different shapes and orientations. This multi-layered design provides enhanced thermal expansion and contraction resistance by distributing stress across multiple interfaces, thereby improving structural integrity during thermal fluctuations.
15. Telescopic Component-Based Expansion Joint Device with Trapezoidal Configuration and Central Spring
SHANDONG HONGDA PROPERTIES CO LTD, TIANYUAN CONSTRUCTION GROUP CO LTD, Tianyuan Construction Group Co., Ltd., 2020
Expansion joint anti-cracking device for concrete structures that provides enhanced anti-cracking performance through a novel telescopic component system. The device comprises a steel support and a telescopic component with a fixed, telescoped section that spans the expansion joint length. The telescopic section is arranged in a trapezoidal shape with side ribs and a central spring, allowing it to maintain a consistent load balance across the joint. This configuration enables the telescopic section to absorb and distribute the differential loading forces between the concrete sections, preventing cracking. The device is integrated into a concrete protective layer and can be used in large-volume concrete structures where traditional expansion joints are insufficient.
16. Walkway Expansion Joint Device with Sliding Cover and U-Shaped Channel Steel Anchor Assembly
BEIJING TEXIDA TRAFFIC SURVEY AND DESIGN INSTITUTE CO LTD, 2020
A walkway expansion joint device that automatically adapts to height difference displacement through a novel anchor connection assembly. The device features a sliding cover assembly mounted on a supporting steel plate, with anchor connection components comprising a U-shaped channel steel and shear nails connecting to the cover and surrounding concrete. The U-shaped channel steel provides additional horizontal displacement capacity, while the shear nails secure the connection to the surrounding concrete. The assembly is supported by a separate steel plate that connects to the expansion joint through shearing nails. This design enables the expansion joint to adapt to height differences while maintaining structural integrity.
17. Fabricated Frame Node Structure with Integrated SMA-ECC Components for Seismic Resistance
FUZHOU UNIVERSITY, 2019
Self-healing fabricated frame node structure and construction method for seismic-resistant buildings. The method integrates SMA-ECC (Self-Healing Advanced Materials for Earthquake-Resistant Concrete) components into the core area of the frame node, while maintaining the conventional concrete structure in the rest of the frame. The SMA-ECC components enable enhanced seismic performance through improved ductility and energy dissipation capacity, while the conventional concrete components maintain the structural integrity and durability. The integrated approach addresses the primary failure mechanisms in seismic-resistant construction by addressing both the core area and the rest of the frame simultaneously.
18. Concrete Member with Spring-Loaded Fiber Rib Micro-Expansion and Composite Reinforcement System
GUANGDONG RESEARCH INSTITUTE OF WATER RESOURCES AND HYDROPOWER, Guangdong Research Institute of Water Resources and Hydropower, 2018
Spring-loaded fiber rib micro-expansion concrete member for coastal structures, comprising a composite reinforcement system that combines fiber rib reinforcement with a spring-loaded expansion mechanism. The system integrates a fiber rib reinforcement matrix with a spring-loaded expansion mechanism that expands when concrete is placed, providing enhanced durability and resistance to seawater corrosion compared to traditional expansion-based systems.
19. Prestressed Steel Cylinder Concrete Pipe with Symmetrical Wire Reinforcement and Temperature-Sensitive Prestressing System
YUNNAN SHENGBOLONG PIPE INDUSTRY CO., LTD., 云南盛博隆管业有限公司, 2018
Embedded prestressed steel cylinder concrete pipe for conveying pipelines, featuring a unique concrete reinforcement structure. The pipe comprises a hollow steel cylinder with a hollow bearing interface, a wire tensioning plate, and longitudinal prestressed steel wire. The pipe's concrete layer is reinforced with a mortar protective layer, while the steel wire is installed in a symmetrical configuration around the hollow bearing interface. The pipe's temperature-sensitive prestressing device is integrated into the concrete reinforcement system, enabling controlled expansion and contraction responses to environmental conditions.
20. Steel Fiber Reinforced Concrete Composite Column with Thin-Wall Steel Pipe Core
华侨大学, HUAQIAO UNIVERSITY, 2018
Buckling-resistant steel fiber reinforced concrete composite column comprising a thin-wall steel pipe core. The column comprises a steel pipe core with a wall thickness less than 0.5 mm, reinforced with steel fibers, and a concrete jacket. The steel pipe core is reinforced with steel fibers to enhance its buckling resistance. The concrete jacket provides additional strength and stability while minimizing material thickness, allowing the steel pipe core to maintain its critical buckling resistance properties.
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