Mechanically Detachable Membrane for Waterproofing
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Solution Overview
Problem
Below ground waterproofing of concrete foundation walls faces challenges in securely fastening waterproofing membranes due to movement of lagging walls relative to concrete walls, leading to tears and splits, which are difficult to repair as the exterior surfaces are inaccessible.
Innovation Solution
A mechanically detachable membrane system is developed, where a fastener with a base and body portion is affixed to the membrane, extending into a cavity in the retaining structure, allowing for detachment after concrete curing, using a detachment mechanism to prevent tears and splits from movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the waterproofing membrane is permanently fastened to the lagging wall, then the membrane is securely attached during construction, but the membrane becomes vulnerable to tears and splits when the lagging wall moves relative to the concrete wall
Solution Approach 1:
The fastening system transitions from a static permanent attachment to a dynamic detachable attachment. The membrane is initially fastened to the lagging wall during construction, then deliberately detached after the concrete wall cures. This dynamic approach allows the system to adapt to the relative movement between the lagging wall and concrete wall, preventing membrane damage while maintaining attachment strength when needed.
Solution Approach 2:
The membrane is fastened to the lagging wall in advance of the concrete wall curing process. This preliminary attachment ensures the membrane is securely in position during construction, and the fasteners are designed to be easily detached after curing completes, allowing the membrane to remain attached to the concrete wall while the lagging wall can move independently.
2Reliability
If the membrane is detached from the lagging wall after concrete curing, then the membrane is protected from damage by lagging wall movement, but the detachment mechanism adds complexity to the fastening system
Solution Approach 1:
The fastening system is divided into separate components: a fastener with a head portion and shaft portion, and corresponding receiving features in the lagging wall and membrane. This segmentation allows the fastener to be easily detached by removing the shaft portion from the lagging wall, providing a simple detachment mechanism that doesn't significantly increase overall system complexity while enabling membrane protection.
3Strength
If conventional permanent fastening is used, then the membrane is securely attached during construction, but repair becomes difficult when the exterior surface is inaccessible
Solution Approach 1:
The system uses a dynamic fastening approach where the membrane is temporarily attached to the lagging wall during construction, then deliberately detached after curing. This allows the membrane to remain securely attached to the concrete wall (which has accessible interior surfaces for repair) while the lagging wall can move independently, making the membrane accessible for repair through the interior of the concrete wall.
Data Source
AI summary
In a method of attaching a membrane to a composite structure, a base portion of a fastener is affixed to a membrane such that a body portion of the fastener extends from a rear surface of the membrane. The body portion of the fastener is assembled with a retaining structure to secure the rear surface of the membrane against an exterior surface of the retaining structure. A curable composite is deposited against a front surface of the membrane, with the curable composite curing to form a composite structure attached to the front surface of the membrane. A detachment mechanism is operated to separate the body portion of the fastener from the base portion of the fastener, thereby detaching the membrane from the retaining structure.