Wood-Concrete Composite Element With Engineered Wood Webs
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Solution Overview
Problem
Existing timber-concrete composite slabs face complexity and high costs due to bonding methods that do not optimally utilize mechanical properties, and systems with solid wood webs are prone to premature failure from inherent weaknesses like knots, leading to increased thickness and material usage.
Innovation Solution
A semi-finished product with an alternating arrangement of bottom chord elements made of wood and web elements made of engineered wood-based material, bonded together to distribute tensile forces evenly and prevent cracking, combined with a concrete layer to form a timber-concrete composite element.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If solid wood composite webs are used to embed the timber component in the concrete component, then the bond between timber and concrete is achieved, but the inherent weaknesses in solid wood (knots, irregular grain patterns) lead to cracking and premature failure
Solution Approach 1:
The patent changes the material parameter from solid wood to engineered wood-based materials (particle board, OSB, laminated veneer lumber) which have fundamentally different structural properties. These engineered materials eliminate knots and irregular grain patterns while providing consistent mechanical properties, directly resolving the reliability-strength contradiction by transforming the material's internal structure rather than working around its limitations
Solution Approach 2:
The patent employs composite wood-based materials that combine wood particles, strands, or veneers with adhesives to create a homogeneous engineered product. This composite approach eliminates the natural weaknesses of solid wood while maintaining wood's beneficial properties, achieving both high bond reliability and transverse tensile strength through the synergistic combination of wood fibers and bonding agents
2Reliability
If composite sheets or webs made of plastic, steel mesh, or woven fabric are used instead of solid wood, then cracking is prevented, but the manufacturing process becomes more complex and costly due to diverse materials and bonding requirements
Solution Approach 1:
The patent applies homogeneity by using wood-based engineered materials that are uniform in composition and properties throughout. This eliminates the need for different material types (plastic, steel, fabric) and their associated different bonding requirements, simplifying manufacturing while maintaining reliability. The homogeneous wood-based material can be bonded using consistent adhesive procedures across all applications
Solution Approach 2:
The patent changes the material parameter from diverse synthetic materials to engineered wood-based materials, which can be processed and bonded using similar woodworking and adhesive techniques. This parameter change reduces manufacturing complexity by standardizing the material type while maintaining the crack-prevention benefits of engineered materials
3Reliability
If recesses are made in the tension flanges to insert webs connecting to the compression flange, then the webs can be embedded in concrete, but the recesses reduce the cross-sectional area and weaken the tension flanges
Solution Approach 1:
The patent extracts the web elements from the tension flange recesses and positions them on the top surface of the timber component. This extraction eliminates the need for recesses that would reduce the tension flange cross-section, thereby maintaining full tensile strength while still allowing web embedding in concrete through the protruding top surface configuration
Solution Approach 2:
The patent moves the web embedding location from within the tension flange (internal dimension) to the top surface (external dimension). By positioning web elements to protrude from the top surface rather than being inserted into recesses, the solution maintains the full cross-sectional area of the tension flange while achieving concrete embedding in a different spatial dimension
Data Source
Figure 1a~1b
Figure 1c
Figure 1d~1e
AI summary
The invention relates to a semi-finished product (104, 204, 404) for the production of a wood-concrete composite building element (100, 200, 400) with a stacking arrangement (106) comprising several bottom chord elements (108, 109) made of wood and several web elements (110, 310), wherein the several bottom chord elements (108, 109) and the several web elements (110, 310) are arranged side by side in a stacking direction (112) and glued together, so that the bottom chord elements (108, 109) and the web elements (110, 310) together form a bottom (114) and an opposite top (116) of the stacking arrangement (112), wherein the web elements (110, 310) project areas (122) on the top (116) beyond the bottom chord elements (108, 109) to whose at least partial embedding in concrete, wherein the several bottom chord elements (108, 109) and the several web elements (110, 310) are arranged alternately next to each other in the stacking direction (112) and wherein the web elements (110,310) are made of wood-based material. The invention further relates to the use of the semi-finished part (104, 204, 404) as well as a wood-concrete composite building element (100, 200, 400) and a method for its production.