Precast Concrete Panel Connection System Thermal Bridge Reduction

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Solution Overview

Problem

Current connection systems for prefabricated reinforced concrete panels face issues such as significant heat bridges, reduced load-bearing capacity due to thermal expansions, complex and costly installation processes, and increased risk of cracking and warping, especially when transitioning from horizontal to vertical position during curing.

Innovation Solution

A connection system comprising hollow main connections with expansion absorbers and smooth, L-bent secondary connections, optimized for stress distribution and thermal expansion absorption, reducing heat bridges and allowing for quick and versatile assembly, with materials like steel and polystyrene for enhanced durability and ease of installation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If main connections are made of considerable size to bear the weight of the outer layer, then load-bearing capacity is improved, but heat bridge effects increase

Engineering Contradiction:
Improveload-bearing capacityVSAvoidheat bridge effects
Core Design Contradiction:
StrengthVSObject-generated harmful factors

Solution Approach 1:

The connection system is segmented into multiple smaller connections distributed across the panel surface, replacing a few large connections. This segmentation maintains total load-bearing capacity while reducing the size of each individual connection, thereby minimizing heat bridge effects at each connection point.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Instead of using one or two large main connections, the system uses multiple identical smaller connections arranged in a pattern across the panel. Each connection is a simplified copy of the others, distributing the structural function while reducing thermal bridging at each location.

Inventive Principle:
Principle #26Copying

2Reliability

If connections are made to absorb thermal expansions, then cracking and warping are reduced, but load-bearing capacity may be compromised

Engineering Contradiction:
Improveresistance to cracking and warpingVSAvoidload-bearing capacity
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The connections incorporate dynamic elements that allow controlled movement and rotation to accommodate thermal expansion and contraction. This dynamic capability enables the connections to absorb thermal stresses without compromising their load-bearing function, as they can adapt their configuration while maintaining structural integrity.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The connection design allows for changes in geometric parameters (such as angle and position) in response to thermal expansion. By changing these parameters dynamically, the connections can absorb thermal stresses while maintaining sufficient load-bearing capacity through their adjusted configuration.

Inventive Principle:
Principle #35Parameter changes

3Stress or pressure

If multiple identical connections are distributed across the panel, then stress distribution is improved, but each connection must be smaller and may be insufficient if one fails

Engineering Contradiction:
Improvestress distributionVSAvoidindividual connection capacity
Core Design Contradiction:
Stress or pressureVSStrength

Solution Approach 1:

While the overall system uses multiple identical connections for stress distribution, each connection is designed with local quality enhancements - such as optimized geometry, material properties, or anchorage features - that ensure each individual connection has sufficient capacity to handle its share of the load even if others fail.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The connection design includes built-in safety margins and redundant capacity, preparing in advance for potential failure of individual connections. Each connection is over-designed relative to its minimum required capacity, providing a cushion that prevents catastrophic failure if one connection becomes compromised.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

4Strength

If connections pass through the insulating layer to unite concrete layers, then structural integrity is improved, but heat bridge effects increase

Engineering Contradiction:
Improvestructural integrityVSAvoidheat bridge effects
Core Design Contradiction:
StrengthVSObject-generated harmful factors

Solution Approach 1:

The connection system uses intermediary elements that bridge the concrete layers while minimizing thermal conduction. These intermediaries may include insulating materials or thermally broken designs that maintain the structural connection function while interrupting the thermal path through the insulating layer.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The connections utilize composite material construction, combining materials with different thermal properties. The connection may use metal components for structural strength combined with insulating materials to break the thermal path, creating a composite structure that provides both structural integrity and thermal performance.

Inventive Principle:
Principle #40Composite materials

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 system effectively minimizes heat bridges, maintains load-bearing capacity under thermal expansions, simplifies manufacturing and installation, and reduces the risk of cracking and warping, while being cost-effective and adaptable to various construction conditions.

Implementation Method 1

a device, called expansion absorber, to take up expansions, for instance made by welding longitudinal elements and connections binding the two concrete layers

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

at least one insulating layer (3) arranged between said inner layer (7) and said outer layer (4)

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Data Source

PatentEP3081714B1Connection system for precast reinforced concrete panels
Publication Date: 2018.05.09 MARZI GIANFRANCO
  • EP3081714B1 patent drawingFigure 1a~1b
  • EP3081714B1 patent drawingFigure 2
  • EP3081714B1 patent drawingFigure 3a~3d

AI summary

The present invention is in the field of reinforced concrete structures, more particularly prefabricated indoor and outdoor structures comprising precast reinforced concrete panels, which may comprise also layers of thermal and/or acoustic insulation. The present invention discloses an innovative connection system of the panel layers through main and secondary interacting connections, to obtain precast reinforced concrete panels with insulating elements.