Variable Core Forming Member for Slipform Casting
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Solution Overview
Problem
In slipform casting of hollow core slabs, the uniform thickness of webs between cores results in increased weight and decreased load capacity due to uniform shear stress distribution, as core forming members cannot be adjusted during the casting process, necessitating additional concrete filling at the ends to enhance strength, which slows down the manufacturing process.
Innovation Solution
The width and height of core forming members are dynamically adjusted during the casting process to vary the thickness of webs between cores, allowing for thicker webs at the ends for enhanced shear stress durability and thinner webs in the middle for reduced weight, using electrical, pneumatic, or hydraulic means to change the dimensions of the core forming members.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If uniform thickness of webs between cores is maintained throughout the slab, then manufacturing process is simplified, but weight increases and load capacity decreases
Solution Approach 1:
The core forming member is designed with variable cross-sectional width along its length, creating different web thicknesses at different locations. The ends of the member have smaller width to produce thicker webs for high shear stress areas, while the middle section has larger width to produce thinner webs for low shear stress areas, optimizing both structural performance and weight reduction
2Ease of manufacture
If uniform thickness of webs between cores is maintained throughout the slab, then manufacturing process is simplified, but shear stress resistance decreases
Solution Approach 1:
The core forming member incorporates varying width along its length to create location-specific web thicknesses. The reduced width at the ends produces thicker webs that resist high shear stresses from support reactions, while the increased width in the middle produces thinner webs where shear stresses are lower, achieving strength optimization without complicating the manufacturing process
3Strength
If additional concrete filling is added at the ends to enhance strength, then shear stress resistance increases, but manufacturing process slows down
Solution Approach 1:
The core forming member is pre-designed with variable cross-sectional dimensions before casting. The varying width along its length pre-establishes the optimal web thickness distribution, with thicker webs at the ends providing enhanced shear stress resistance directly during the casting process itself, eliminating the need for subsequent concrete filling operations and maintaining high manufacturing speed
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
This approach optimizes the cross-sectional area of hollow core slabs by varying the core dimensions, enhancing shear stress resistance at the ends while minimizing concrete usage and weight, allowing for more efficient and faster production.
Implementation Method 1
the width and height of core forming members are dynamically adjusted during the casting process to vary the thickness of webs between cores
Data Source
AI summary
A method for casting a hollow core concrete product with a substantially horizontal slipform casting process, where concrete mass is fed at least in one feeding stage through a limited cross-section (5, 6, 7) moving progressively along with the cast, and at least one core is formed in the concrete product to be cast with a core forming member (4), wherein the thickness of webs between the cores of the product to be cast are changed during the slipform casting process by changing the width of the at least one core forming member (4). The invention also relates to such an apparatus and a core forming member.