Pre-stressed Anchor Mandrel with Preformed Grouting Pipe
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional non-pre-stressed anchors in corrosive soil and water environments are prone to cracking, leading to durability issues and potential safety hazards due to rust expansion, while pre-stressed anchors require a lengthy construction process and can cause water leakage in basements.
Innovation Solution
An anchor assembly with a prefabricated pre-stressed concrete mandrel and cast-in-place anchoring slurry, featuring a grouting pipe preformed at the mandrel, which enhances bonding and pullout resistance, and allows for pre-tensioning without preforming holes in the bottom slab, thus preventing water leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pre-stressed anchors are used to control cracks and improve durability, then the durability and crack resistance are improved, but the construction period is extended due to the requirement of tensioning after bottom slab pouring
Solution Approach 1:
The patent applies preliminary action by pre-forming the grouting pipe in the mandrel during factory production, before the anchor is installed. This allows the grouting system to be ready in advance, enabling immediate grouting after anchor installation without requiring subsequent hole preformation or delayed tensioning operations, thus reducing construction period while maintaining pre-stressed durability benefits
2Reliability
If pre-stressed anchors require preforming holes in the bottom slab for tensioning, then the pre-stressing function is achieved, but water leakage in the basement occurs
Solution Approach 1:
The grouting pipe is pre-formed in the mandrel during factory production, eliminating the need for subsequent hole preformation in the bottom slab. This preliminary preparation prevents water leakage pathways from being created during construction, while still enabling the pre-stressed anchor to function effectively for anti-floating protection
Solution Approach 2:
The patent extracts the grouting pipe formation step from the on-site construction process and relocates it to factory production. By taking out this operation and performing it in advance, the harmful effect of creating holes in the bottom slab (which causes water leakage) is eliminated, while the essential grouting function is preserved
3Ease of manufacture
If non-pre-stressed anchors are used for simple construction process and low cost, then the ease of manufacture and productivity are improved, but cracks occur leading to durability problems in corrosive environments
Solution Approach 1:
The mandrel is pre-stressed in the factory during manufacturing, before installation. This preliminary pre-stressing action ensures that the anchor has crack-resistant properties from the start, eliminating the need for complex on-site pre-stressing operations while maintaining durability in corrosive environments. The grouting pipe is also pre-formed, keeping the on-site process simple
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 solution effectively prevents cracks in anchors, improves durability, reduces construction time, and lowers costs by enabling pre-stressed anchors to meet design requirements without the need for on-site pouring and hole preformation, while saving rebar material and enhancing anti-floating performance.
Implementation Method 1
pre-stressed tendons are arranged inside the pre-stressed concrete mandrel and are prefabricated by a pretensioning method
Implementation Method 2
a cast-in-place anchoring slurry is positioned at an outer side, wraps the pre-stressed concrete mandrel
Implementation Method 3
improve the bonding performance between the anchor and the hole wall
Data Source
AI summary
Provided is an anchor assembly having a pre-stressed mandrel, which consists of an inner pre-stressed concrete mandrel and an outer cast-in-place anchoring slurry, wherein pre-stressed tendons are arranged inside the concrete mandrel and are prefabricated by a pretensioning method; the anchoring slurry wraps the pre-stressed concrete mandrel, and the cast-in-place anchoring slurry is formed by placing the pre-stressed concrete mandrel in a pile hole, and solidifying after primary grouting or secondary grouting. According to the anchor assembly, the pre-stress is not required to be tensioned and locked on site, so that the quality of the pre-stressed mandrel can be ensured, the on-site construction period can be greatly shortened, and the existing pre-stressed and common non-pre-stressed anchors can be replaced.