Pre-cast Concrete Joint Using Vacuum-Assisted Grout Injection
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Solution Overview
Problem
Conventional methods for constructing structures with pre-cast concrete elements are labor and time intensive and result in weaker structures compared to field-poured elements, necessitating a more efficient method for constructing stronger structures using pre-cast concrete.
Innovation Solution
The method involves assembling pre-cast concrete column and beam sections with embedded threaded rods, where the rods are rotated to extend into channels in the beam sections, and grout is applied under vacuum suction to create a strong structural joint, with the rods being held in place solely by the grout, eliminating engagement with any threaded structure within the channel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If pre-cast concrete elements are used, then construction time and labor are reduced, but the resulting structure is weaker compared to field-poured elements
Solution Approach 1:
The concrete structure is divided into pre-cast column sections and beam sections that are manufactured separately and then assembled on-site. Each section contains embedded assemblies with threaded rods that facilitate connection. This segmentation enables factory production of high-strength concrete elements with controlled curing conditions, while maintaining construction efficiency through rapid assembly.
Solution Approach 2:
The threaded rods and channels are pre-installed into the pre-cast concrete sections during manufacturing. The grout ports are also formed in advance. These preliminary actions ensure that when the sections are assembled on-site, the connection components are already in position, eliminating the need for complex field assembly operations and ensuring consistent connection quality.
Solution Approach 3:
The traditional mechanical connection methods (such as bolting or welding) are replaced with a grout-based chemical bond. The threaded rods extend into channels and are held in place solely by grout that flows through the joint and cures to create a monolithic connection. This substitution eliminates the need for complex mechanical fasteners and achieves field-poured strength with pre-cast efficiency.
2Strength
If field-poured concrete methods are used, then stronger structures are achieved, but construction becomes labor and time intensive
Solution Approach 1:
The structure is segmented into pre-cast sections that are manufactured in controlled factory environments where optimal curing conditions can be maintained to achieve high strength. The segmentation allows parallel production of multiple sections, improving overall productivity while maintaining the strength characteristics of field-poured concrete through controlled manufacturing processes.
Solution Approach 2:
All connection components (threaded rods, channels, grout ports) are pre-installed during factory manufacturing. This preliminary action eliminates time-consuming field operations and reduces labor requirements during assembly, achieving high construction efficiency while maintaining the structural integrity and strength of field-poured connections.
Solution Approach 3:
The complex mechanical connection systems required in field-poured construction are replaced with a simplified grout-based connection system. The grout flows through pre-formed channels and ports, bonding the pre-cast sections together to create a monolithic structure with field-poured strength, but with the construction efficiency of pre-cast assembly.
3Strength
If threaded rods engage with threaded structures in channels, then mechanical connection strength is improved, but the complexity of the joint increases
Solution Approach 1:
The threaded engagement mechanism is extracted from the channel structure. Instead of threading the channel itself, the invention uses smooth-bored channels that receive the threaded rods without mechanical engagement. The threads on the rods serve only for insertion and positioning, while the final connection strength comes from the grout bond, simplifying the channel design and reducing joint complexity.
Solution Approach 2:
Grout is introduced as an intermediary material between the threaded rod and the channel. The grout flows through the joint and channel, bonding the rod to the surrounding concrete structure. This intermediary eliminates the need for direct mechanical engagement between the rod and channel, simplifying the joint design while maintaining or enhancing connection strength through the grout's bonding properties.
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 approach enhances the efficiency and strength of pre-cast concrete structures by providing a robust joint between column and beam sections, reducing construction time and labor while achieving structural integrity comparable to field-poured methods.
Implementation Method 1
feeding grout into the joint while applying vacuum suction to the at least one grout port, the vacuum suction causing grout to flow through the joint, the channel, and the grout port of the second assembly
Data Source
AI summary
Various implementations include methods and apparatuses for constructing a concrete structure. In one implementation, a structure includes a pre-cast concrete column section and a pre-cast concrete beam section. The column section includes an embedded first assembly with a threaded rod, and the beam section includes an embedded second assembly defining a channel for receiving the threaded rod. Grout is fed through a joint between the column and beam sections into the second assembly to couple the threaded rod with the second assembly. The grout is urged through the joint and the second assembly by gravity and by applying vacuum suction to a grout port defined by the second assembly. The grout port extends between the channel of the second assembly and an external face of the beam section.