Deformation compensation method for non-standard formwork

Technique for calculating formliner compensation by height using cylindrical coordinate radius functions and deformation error equations

This technology represents the reference shape of an irregular structure as a radius function based on angle and height from the central axis. It calculates the radius change caused by concrete lateral pressure and pre-compensates the formwork shape accordingly. A program on an information processing device handles everything from modeling the reference shape to calculating the compensation values.

F3D irregular formwork, which uses 3D printers to cut and stack EPS panels, is lighter, cheaper, and faster to produce than wood or steel formwork. However, due to the low strength and elastic modulus of EPS, the formliners deform significantly under concrete lateral pressure. Since lateral pressure varies by layer depending on the distance between the central axis and the formliner interface, the entire formwork shape changes, leading to issues where the final structure does not match the design drawings.

This technology defines the reference deformation as the difference between the post-deformation radius and the original radius at any given angle and height (Equation 2). It then defines the compensated shape and the compensated deformation shape using a radius function that incorporates the compensation value, calculating the compensated deformation amount via Equation 3. By evaluating the error between the ratio of reference deformation to reference shape and the ratio of compensated deformation to compensated shape (Equation 4), it determines the final compensation value using Equation 1—based on the premise that the error is near zero—ensuring the compensated shape matches the reference shape after lateral pressure is applied. This can be applied to 3D-printed EPS formliner production, curved concrete structures like bridge piers and towers, and irregular facade precast panels, allowing for precise cutting dimensions that account for lateral pressure at every point on each stacked formliner layer.

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Key Features:

• Modeling a reference shape corresponding to the irregular structure using a program installed on an information processing device
• Modeling a reference deformation shape by considering the concrete lateral pressure applied to the reference shape and calculating the reference deformation, which is the difference from the reference shape
• Modeling a compensated deformation shape by considering the concrete lateral pressure applied to the compensated shape, which incorporates the compensation value, and calculating the compensated deformation, which is the difference
• Calculating the compensation value so that the error between the ratio of compensated deformation to compensated shape and the ratio of reference deformation to reference shape approaches zero

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This invention was developed with support from the Korea Agency for Infrastructure Technology Advancement (KAIA) for the development of 3D printing equipment and production technology for irregular members.

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