Concrete-Encased CFST Column Connection Structure
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Solution Overview
Problem
There is a lack of reliable and efficient connection structures for concrete-encased concrete-filled steel tube (CFST) columns, particularly for connecting two split CFST columns, which is crucial for ensuring connection strength in complex construction applications.
Innovation Solution
A connection structure comprising a core positioning sleeve, longitudinal bar sleeves, a hoop restraining sleeve, and an external sealing sleeve, with slurry-flowing holes and cushions to facilitate concrete slurry infusion and enhance adhesion, is used to connect exposed steel tubes and longitudinal bars between split CFST columns, ensuring a strong and sealed bond.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional connection methods are used to connect split CFST columns, then construction simplicity is maintained, but connection strength and reliability are insufficient
Solution Approach 1:
The connection structure is divided into multiple functional components: core positioning sleeve for alignment, longitudinal bar sleeves for reinforcement bar connection, hoop restraining sleeve for lateral constraint, and external sealing sleeve for waterproofing. Each component performs a specific function, allowing the complex connection task to be achieved through modular, organized segments rather than a monolithic structure.
Solution Approach 2:
The connection structure employs nested sleeves where the core positioning sleeve is placed inside the longitudinal bar sleeves, which are in turn constrained by the hoop restraining sleeve, and finally sealed by the external sealing sleeve. This nested arrangement allows multiple functions (positioning, reinforcement, constraint, sealing) to be integrated in a compact, space-efficient manner while maintaining clear functional separation.
2Ease of manufacture
If formwork is used to fill concrete between split CFST columns, then concrete filling is achieved, but construction complexity and time increase
Solution Approach 1:
The traditional formwork is extracted and replaced with a simplified sealing system. The external sealing sleeve provides the necessary containment for concrete filling without requiring complex formwork assemblies. The slurry-flowing holes in the core positioning sleeve enable concrete to flow directly into the connection zone, eliminating the need for separate formwork installation and removal processes.
Solution Approach 2:
The core positioning sleeve is pre-equipped with slurry-flowing holes before the connection process begins. This preliminary configuration allows concrete slurry to flow directly into the connection zone through the hollow longitudinal bars and around the steel tubes, eliminating the need for separate formwork installation and accelerating the construction process.
3Ease of operation
If simple sleeve connection is used, then construction ease is improved, but sealing performance and structural integrity deteriorate
Solution Approach 1:
The connection structure combines multiple materials and functions: steel sleeves for structural strength and positioning, sealing materials in the external sealing sleeve for waterproofing, and concrete slurry for bonding and filling. This composite approach ensures that each material performs its optimal function, achieving both ease of construction and high reliability in sealing and structural integrity.
Solution Approach 2:
The external sealing sleeve acts as a flexible containment shell that provides waterproof sealing around the connection zone. The sleeve's design allows it to conform to the connection geometry while maintaining sealing integrity, ensuring that concrete filling and final connection are protected from water infiltration without requiring rigid, complex formwork.
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
The proposed connection structure effectively connects split CFST columns by filling the space between the columns with concrete slurry, providing enhanced strength and stability without the need for formwork, thus addressing the existing gap in reliable connection methods.
Implementation Method 1
a plurality of slurry-flowing holes are opened on a side wall of the core positioning sleeve to facilitate a concrete slurry inflow in the space between and surrounding the two exposed steel tubes
Implementation Method 2
An inner side wall of the core positioning sleeve is circumferentially provided with a plurality of cushions for bracing the exposed steel tubes
Implementation Method 3
The hoop restraining sleeve is sleeved outside the core positioning sleeve and fixedly connected to an outer side wall of the core positioning sleeve through one or more first connection keys
Data Source
AI summary
The present invention discloses a concrete-encased concrete-filled steel tube (CFST) column connection structure, a concrete-encased CFST column comprising such a connection structure, and a construction method for constructing such a concrete-encased CFST column, in the technical field of connection of concrete-encased CFST columns. Exposed steel tubes at the connection ends of two split concrete-encased CFST columns are connected through a core positioning sleeve of a concrete-encased CFST column connection structure. Exposed longitudinal bars of the two split concrete-encased CFST columns are connected through longitudinal bar sleeves of the concrete-encased CFST column connection structure. A space between the two split concrete-encased CFST columns is sealed by an external sealing sleeve of the concrete-encased CFST column connection structure; and the space in the external sealing sleeve and around the first and second exposed steel tubes is filled with a concrete slurry.