Compactible Inner Form Assembly for Concrete Shafts
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Solution Overview
Problem
Existing formwork technologies face challenges when forming multi-floor building shafts, particularly in efficiently compacting and expanding the formwork to accommodate varying cross-section configurations and in facilitating easy hoisting and delamination from concrete.
Innovation Solution
A compactible inner form assembly comprising a quadrant of boards and corner posts with angled interface surfaces, which mechanically interlock with catches sliding along slots, allowing the assembly to compact and expand vertically, and featuring design elements that enable easy delamination and hoisting using a crane.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the formwork uses a compactible design to reduce cross-section, then the productivity and space utilization improve, but the device complexity increases due to the need for corner posts, slots, and catching mechanisms
Solution Approach 1:
The formwork is divided into four separate boards that can move independently relative to each other, allowing the structure to be segmented and reconfigured. Each board is connected to corner posts that guide their movement, enabling the formwork to transition between expanded and compacted states through coordinated segmental motion.
Solution Approach 2:
The formwork incorporates dynamic elements including slots in the corner posts that allow vertical movement of boards, and catching mechanisms that enable controlled compaction. The system transitions from a static formwork to a dynamic one where boards can move vertically and horizontally to change the cross-sectional configuration.
2Ease of operation
If the corner posts have large orthogonal skin surfaces, then the structural integrity and ease of operation improve, but the posts stick to the concrete during hoisting
Solution Approach 1:
The corner posts have non-uniform surface characteristics: large angled interface surfaces for structural integrity and operation, but small reduced orthogonal skin surfaces that contact the concrete. This local variation in surface area allows the posts to maintain strength where needed while minimizing adhesion to concrete during hoisting operations.
3Productivity
If the formwork assembly is made tall to form multi-storey shafts, then the productivity improves by forming entire floor sections at once, but the weight and hoisting difficulty increase
Solution Approach 1:
The formwork is segmented into four boards that can move independently, allowing the structure to be compacted vertically. This segmentation enables the formwork to achieve a compacted state during hoisting, reducing its effective footprint and making it easier to maneuver despite its height and weight.
Solution Approach 2:
The formwork transitions between expanded and compacted configurations dynamically. During hoisting, the boards move to a compacted position reducing the assembly's horizontal footprint. When forming shafts, the boards expand to their full configuration. This dynamic reconfiguration allows the formwork to be both tall for productivity and manageable for hoisting.
4Manufacturing precision
If the boards are held rigidly by the corner posts, then the manufacturing precision and structural integrity improve, but the ability to compact and expand the formwork deteriorates
Solution Approach 1:
The connection between boards and corner posts is designed to be dynamic rather than rigid. The slots in the corner posts allow vertical movement of the boards, and the catching mechanisms enable horizontal movement for compaction. This dynamic connection maintains manufacturing precision when the formwork is in its formed position while allowing the necessary movement for compaction and expansion operations.
Solution Approach 2:
The system changes its structural parameters between states: in the expanded state, the boards are held firmly for precision forming; in the compacted state, the boards move to a different position. The corner posts and catching mechanisms facilitate this parameter change, allowing the formwork to transition between rigid precision-forming mode and mobile compaction mode.
Data Source
AI summary
An inner form assembly for forming concrete building shafts has a quadrant of boards and corner posts therebetween. Each corner post has angled interface surfaces converging towards exposed orthogonal skin surfaces. The boards have respective angled interface surfaces meeting respective angled interface surfaces of the corner posts so that the boards are held orthogonally by the corner posts. The angled interface surfaces of the corner posts and the boards slidably bear against each other and mechanically interlock with catches sliding along slots so that the boards move in together to form a compacted cross section configuration when the corner posts rise with respect to the boards and the boards move out to form an expanded cross section configuration when the corner posts fall with respect to the boards and wherein the orthogonal skin surfaces come into alignment with respective skin surfaces of adjacent boards.