Manhole Cover Frame Segmented Concrete Cast Receptacle
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Solution Overview
Problem
Existing manhole cover installation methods fail to adequately distribute heavy traffic loads and often result in cracking between the manhole cover and asphalt, requiring excessive materials and longer installation times, while also being unsuitable for porous asphalt due to low load-bearing capacity.
Innovation Solution
A manhole cover arrangement with a two-part frame consisting of a cast receptacle and a concrete support body, where the receptacle has angled legs that surround the support body, creating a single joint with the road surface, reducing stress transfer and material usage, and using a permanently elastic plastic mortar for sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conical milling method is used to install the manhole cover frame, then the installation process is simplified, but the traffic loads are inadequately distributed and cracking occurs between the manhole cover and asphalt
Solution Approach 1:
The manhole cover frame is divided into two separate parts: a cast receptacle and a concrete support body. The concrete support body remains in the milled opening to distribute loads, while the cast receptacle is inserted later to receive the closure element. This segmentation allows each component to fulfill its specific function optimally.
Solution Approach 2:
The cast receptacle is nested within the concrete support body structure. The receptacle fits into the support body with a positive and material fit connection, creating a nested arrangement where the inner component (receptacle) is surrounded by the outer component (support body), combining their strengths.
2Reliability
If two joints are formed (grouting mortar joint and joint material joint), then comprehensive sealing is achieved, but material usage increases and installation time is extended
Solution Approach 1:
The functions of multiple joints are merged into a single joint. The cast receptacle with its downwardly angled leg creates one continuous joint with the road surface that simultaneously provides sealing, load distribution, and structural connection, eliminating the need for separate grouting mortar and joint material applications.
3Ease of manufacture
If a thin asphalt layer is applied over the concrete support body, then the manhole cover can be installed, but the connection is insufficient under heavy traffic loads
Solution Approach 1:
The manhole cover frame uses a composite structure combining cast material (receptacle) and concrete material (support body). This composite design leverages the strengths of both materials: the cast receptacle provides precise geometry and load distribution, while the concrete support body offers structural strength and integration with the road base.
4Adaptability or versatility
If porous asphalt is used for inner-city paving, then permeability is achieved, but the load-bearing capacity is too low for heavy traffic loads
Solution Approach 1:
The frame structure is segmented into a deep concrete support body that embeds into the road base for strength, and a lighter cast receptacle that sits at the surface. This allows the use of porous asphalt in the surface course while the concrete support body beneath provides the necessary load-bearing capacity.
Data Source
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AI summary
The invention relates to a manhole cover assembly and an installation method for such an assembly for use in new road construction and rehabilitation projects, comprising a closure element and a manhole cover frame. The manhole cover frame is formed in two parts, consisting of a cast receptacle for receiving the closure element and a concrete support body. The concrete support body and the cast receptacle are at least partially connected to each other in a form-fit and material-locking manner. The cast receptacle projects beyond the concrete support body in the direction of the closure element, and the concrete support body has a downwardly tapered side surface facing away from the manhole. The cast receptacle has a downwardly angled leg on the side of the manhole cover assembly facing away from the manhole, which at least partially encompasses the concrete support body on its side facing away from the manhole.