Post-Tensioned CLT Panel Assembly with Pre-Formed Tendon Grooves

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Solution Overview

Problem

Conventional construction methods using reinforced concrete and structural steel in high-rise buildings are environmentally intensive and have structural limitations for longer unsupported panel spans, and the manufacture of pre-stressed tendon reinforced CLT panels is hindered by design limitations and slow curing processes.

Innovation Solution

A cellulose-based structural beam or panel assembly with a cross-laminated timber core reinforced by post-tensioned tendons, which are secured under tension and grouted within channels in the core, allowing for pre-manufactured panels that can span long distances and provide structural integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If pre-stressed tendon reinforced CLT panels are manufactured using conventional methods, then structural strength is improved, but manufacturing complexity and curing time increase significantly

Engineering Contradiction:
Improvestructural strengthVSAvoidmanufacturing complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The tendon grooves are pre-formed into the CLT panel during the panel manufacturing process, before the tendons are installed. This allows the structural reinforcement to be prepared in advance, simplifying the subsequent tendon installation and eliminating the need for complex on-site groove formation and curing processes.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The manufacturing process is divided into separate stages: CLT panel fabrication with pre-formed grooves, followed by separate tendon installation and tensioning. This segmentation allows each component to be optimized independently and assembled efficiently, reducing overall manufacturing complexity.

Inventive Principle:
Principle #1Segmentation

2Reliability

If pre-stressed tendon reinforced CLT panels are manufactured with full curing process, then tendon anchoring reliability is improved, but construction productivity decreases

Engineering Contradiction:
Improvetendon anchoring reliabilityVSAvoidconstruction productivity
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The tendon grooves are pre-formed and ready for tendon installation before the panels are shipped to the construction site. This preliminary preparation eliminates the need for on-site groove formation and concrete pouring, allowing tendons to be installed and tensioned immediately upon panel installation, significantly improving construction productivity while maintaining anchoring reliability.

Inventive Principle:
Principle #10Preliminary action

3Stability of the object's composition

If conventional in situ casting methods are used for floor slabs and beams, then structural integrity is improved, but environmental impact and construction time increase

Engineering Contradiction:
Improvestructural integrityVSAvoidenvironmental impact
Core Design Contradiction:
Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The floor structure is divided into pre-manufactured CLT panels with integrated tendon grooves, which are assembled on-site rather than cast in situ. This segmentation eliminates the need for extensive concrete pouring and curing, reducing CO2 emissions from cement production and shortening construction time while maintaining structural integrity through the pre-engineered CLT panels.

Inventive Principle:
Principle #1Segmentation

4Manufacturing precision

If tendon pre-stressing is performed with jack tensioning and end molds, then tendon tensioning precision is improved, but manufacturing speed and adaptability decrease

Engineering Contradiction:
Improvetendon tensioning precisionVSAvoidmanufacturing speed
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The tendon grooves are pre-formed with precise dimensions and orientations during CLT panel manufacturing. This preliminary precision work eliminates the need for complex on-site alignment and positioning operations, allowing tendons to be installed quickly and tensioned efficiently without sacrificing precision, thereby improving both manufacturing speed and adaptability.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3980608B1Cellulose-based structural flooring panel assembly
Publication Date: 2026.03.04 DIALOG IP CORP
  • EP3980608B1 patent drawingFigure 1
  • EP3980608B1 patent drawingFigure 2
  • EP3980608B1 patent drawingFigure 3

AI summary

A cellulose-based structural building panel assembly includes a cross-laminated timber (CLT) core which is reinforced with one or more post-tensioned tendons stressed to a pre-selected tensioning force, following the placement as part of the panel assembly. The tendons are provided within a sleeve which is grouted with a channel formed in an underside of the core and which after post-tensioning of tendons is infilled with a binder securing the tendons in a fully bonded configuration.