Cold Formed Joist Segmented Chord Web System
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Solution Overview
Problem
There is a lack of metal joists designed for composite and non-composite construction applications that are lightweight, strong, durable, economically manufactured, and adaptable to various requirements, as existing prefabricated metal joists lack interchangeable parts for specific applications.
Innovation Solution
A cold-formed metal joist system comprising an upper chord, a lower chord, and a web portion, where each element can be economically manufactured from sheet metal in different dimensions to form a joist suitable for specific applications, with features like channels and flanges for enhanced load resistance and interlocking with concrete for composite applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If prefabricated metal joists are manufactured with fixed dimensions, then manufacturing economy is improved, but adaptability to various application requirements deteriorates
Solution Approach 1:
The metal joist is divided into multiple standardized segments including upper chords, lower chords, and web portions that can be manufactured separately and assembled in different configurations. This segmentation allows a limited set of standardized components to create joists of various spans and load capacities, resolving the contradiction between manufacturing economy and adaptability.
Solution Approach 2:
The standardized metal joist components are designed with universal connection features and standardized dimensions that allow them to serve multiple functions across different applications. The same upper chord component can be used in various joist configurations and span requirements, enabling a limited production catalog to meet diverse construction needs.
2Weight of moving object
If metal joists are made lightweight using thin gauge metal, then ease of installation is improved, but structural strength deteriorates
Solution Approach 1:
The metal joist incorporates curved and shaped elements such as angled web portions and formed chord sections that provide structural strength through geometric configuration rather than material thickness. These shaped components maintain high strength-to-weight ratios by optimizing the distribution of material in load-bearing configurations.
Solution Approach 2:
The joist system combines thin gauge metal components with concrete infill to create a composite structure. The metal framework provides tensile strength and structural form, while the concrete provides compressive strength, together achieving high structural performance with lightweight individual components.
3Strength
If cold forming process is used to increase yield capacity, then structural strength is improved, but manufacturing complexity increases
Solution Approach 1:
The complex cold forming operations are distributed across multiple separate manufacturing steps for different components (upper chords, lower chords, web portions) rather than attempting to form the entire joist in one operation. This segmentation of the manufacturing process reduces the complexity of each individual forming operation while achieving the desired yield capacity enhancement.
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 provides a flexible and strong joist solution that can be adapted to various applications, offering superior load resistance and integration with concrete, enhancing structural integrity and adaptability in construction projects.
Implementation Method 1
Cold forming involves working a material below its recrystallization temperature. Generally, cold forming occurs at the ambient temperature of the work environment. The resultant cold formed material is stronger due to manipulations that have been made to the crystal structure of the material.
Data Source
AI summary
The present invention provides a cold formed joist that can be used in a variety of construction applications. The present cold formed joist consists of three elements, each formed from sheet metal: an upper chord, an intermediate web, and a lower web. These three elements can be produced in different dimensions. The upper chord further consists of a downwardly facing receiving channel adapted to receive the upper edge of the intermediate web, and two upwardly facing channels. The lower chord consists of an upwardly facing receiving channel that is adapted to receive the lower edge of the intermediate web.