Lifting Anchor Assembly for Tilt-Up Concrete Structures
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Solution Overview
Problem
Tilt-up precast concrete structures are difficult to handle due to their weight and susceptibility to damage, requiring effective lifting solutions that existing technologies have not adequately addressed.
Innovation Solution
A lifting anchor assembly with a central portion for engaging lift apparatuses and legs forming an inverted U or V shape, featuring curved sections and spacers to secure the anchor within the concrete structure, dispersing loads and preventing withdrawal, while allowing for adjustable positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional lifting methods are used for tilt-up precast concrete structures, then the structures can be lifted, but the structures are susceptible to damage such as cracking, chipping, and breakage due to their weight and bulkiness
Solution Approach 1:
Lifting anchors are embedded in the concrete structure during the casting process, before the structure is moved. This preliminary placement of lifting attachment points allows for controlled lifting without concentrating stresses on vulnerable concrete surfaces, thereby preventing cracking and chipping during the lifting operation.
Solution Approach 2:
The lifting anchor assembly acts as an intermediary between the concrete structure and the lifting apparatus. It distributes the lifting forces through its legs and curved sections that engage with the concrete, converting concentrated point loads into distributed stresses that the concrete can withstand, thus preventing damage during lifting.
2Ease of operation
If lifting anchors are embedded in precast concrete structures, then handling is facilitated, but the anchors must securely prevent withdrawal while allowing adjustable positioning
Solution Approach 1:
The lifting anchor assembly incorporates curved sections at the lower portions of its legs. These curved geometry features engage with corresponding features in the concrete structure, creating a mechanical interlock that prevents withdrawal of the anchor while the curvature allows for adjustable positioning during installation.
Solution Approach 2:
The lifting anchor assembly is divided into functional segments: a central portion for engaging the lift apparatus, legs that extend downward, and curved lower portions that engage the concrete. This segmentation allows each part to perform its specific function - the central portion provides lifting attachment, the legs provide structural support, and the curved portions provide retention and positioning.
3Strength
If the anchor member has legs extending downward to form an inverted U or V shape, then load capacity is enhanced, but the device complexity increases
Solution Approach 1:
The lifting anchor assembly merges multiple functions into a single integrated component: the central portion provides lifting attachment, the legs provide structural support and load distribution, and the curved lower portions provide retention. This consolidation of functions into one piece maximizes load capacity while minimizing the number of separate components, thereby managing device complexity.
Solution Approach 2:
The lifting anchor assembly is designed as a multi-functional component that simultaneously provides lifting attachment, load distribution, structural support, and retention. The inverted U or V shape of the legs serves multiple purposes: it distributes lifting forces, provides structural rigidity, and creates the curved engagement features for retention, making the single component universally applicable for various lifting scenarios.
Data Source
AI summary
A lifting anchor assembly that is configured to be embedded in a tilt-up concrete structure includes an anchor member that has a central portion configured to engage a lift apparatus and a pair of legs that extend downward from the central portion. A lower portion of each of the pair of legs includes a curved section configured to engage within a concrete structure during its forming process. A spacer may be selected to attach at an end portion of each the pair of legs, where the spacers each extend downward from the anchor member and rest on a floor surface of a concrete form to support the anchor member at a desired spacing from the floor and upright within the concrete structure that is cast in the concrete form.