Half Precast Slab Segmentation for Thick Turbine Foundations

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Solution Overview

Problem

Conventional precast construction techniques are impractical for thick slabs, such as turbine foundations, due to excessive weight and complexity, leading to the adoption of cast in-situ concrete methods despite the advantages of precast construction.

Innovation Solution

A half precast slab structure comprising floor concrete form members with a bottom slab and upright side walls, connected perpendicularly to form a single reinforcing bar arrangement space, allowing for efficient installation of reinforcing bars and concrete, with optional prestressing steel wires and bolts for enhanced connectivity and stiffness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If full precast construction technique is used for thick slabs, then construction time is reduced and productivity is improved, but weight increases excessively making conveyance and installation difficult

Engineering Contradiction:

Improveconstruction timeVSAvoidweight of precast slab

Core Design Contradiction:

ProductivityVSWeight of moving object

Solution Approach 1:

The precast slab is divided into two parts: a precast bottom slab and cast-in-situ upper concrete. This segmentation allows the heavy bottom portion to be manufactured off-site with controlled weight, while the upper portion is added at the construction location, thus reducing the weight of components that need to be conveyed and installed while still achieving the total thickness required for turbine foundations.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention transitions from a fully three-dimensional precast component to a hybrid approach where the bottom slab is precast and the upper portion is cast in-situ. This dimensional change in construction methodology allows weight reduction in the precast portion while maintaining the overall structural requirements.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Productivity

If conventional precast techniques are used for thick slabs, then construction efficiency is improved, but device complexity increases due to difficulty in conveying and installing heavy components

Engineering Contradiction:

Improveconstruction efficiencyVSAvoidcomplexity of conveyance and installation

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

By segmenting the slab into precast bottom slab and cast-in-situ upper concrete, the invention simplifies the conveyance and installation processes. Only the bottom slab needs to be manufactured and transported to the site, significantly reducing the complexity of heavy component handling while maintaining construction efficiency.

Inventive Principle:

Principle #1Segmentation

3Weight of moving object

If cast in-situ concrete method is used for thick slabs, then weight and complexity are reduced, but construction time increases and productivity decreases

Engineering Contradiction:

Improveweight of concrete componentsVSAvoidconstruction time

Core Design Contradiction:

Weight of moving objectVSProductivity

Solution Approach 1:

The bottom slab is manufactured as a precast component in advance at a factory, allowing parallel preparation of multiple components. This preliminary action reduces on-site construction time while keeping individual component weights manageable, thus improving productivity without excessive weight.

Inventive Principle:

Principle #10Preliminary action

4Speed

If conventional precast techniques are used for thick slabs, then construction speed is improved, but reinforcing bar arrangement complexity increases

Engineering Contradiction:

Improveconstruction speedVSAvoidcomplexity of reinforcing bar arrangement

Core Design Contradiction:

SpeedVSDevice complexity

Solution Approach 1:

The reinforcing bar arrangement is segmented into two phases: bottom slab reinforcing bars are arranged during precast manufacturing, and upper concrete reinforcing bars are arranged during on-site casting. This segmentation simplifies each phase's reinforcement work while maintaining construction speed.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS8671641B2Half precast slab and method for structuring half precast slab

Publication Date: 2014.03.18 MITSUBISHI POWER LTD

AI summary

Providing a half precast slab even in a case where the thickness of the slab in the site condition is too thick to apply conventional precast construction techniques. A half precast slab including a plurality of floor concrete form members and, each floor concrete form member being provided with: a bottom slab of a long length, in response to the floor concrete form member; a pair of side walls installed upright along each longitudinal edge of the bottom slab, in response to the floor concrete form member; thereby, each floor concrete form member is arranged so as to be parallel to each other and be tightly connected to the adjacent floor concrete form member, along the direction perpendicular to the longitudinal direction of each floor concrete form member; the height of the side walls other than the side walls on the most outer edge sides of the whole floor concrete form members is set at a common height that is smaller than the height of the side walls on the most outer edge sides.