Precast Concrete Slab Tendon Compression System
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Solution Overview
Problem
Current structural building systems face challenges such as high concrete transportation costs, extended construction times due to concrete curing, and complexity in assembling precast slabs, which can lead to structural instability and increased costs.
Innovation Solution
A structural frame system comprising precast concrete columns and slabs with integrated tendon assemblies that are tensioned to compress elongated edge beams between columns, providing rigidity and stability, and grout is applied to encase the tendons for added strength and protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If fresh concrete is transported from manufacturing site to construction site in specialized vehicles, then the structural frame can be constructed, but the construction costs increase
Solution Approach 1:
The structural system is divided into separate components: precast concrete slabs are manufactured independently at a plant, and steel columns are prepared separately. These segments are then transported and assembled on-site, eliminating the need to transport large volumes of fresh concrete to construction sites.
Solution Approach 2:
Concrete slabs are precast in manufacturing plants under controlled conditions before being transported to the construction site. This preliminary action allows concrete to be prepared in advance with proper mixing and curing conditions, reducing the need for on-site concrete mixing and transportation.
2Strength
If concrete is poured on-site, then the floor slabs can be formed, but the construction time increases due to curing requirements
Solution Approach 1:
Concrete slabs are precast in manufacturing plants where curing can be controlled and optimized. This preliminary action allows the concrete to gain sufficient strength before installation, eliminating the need for extended on-site curing time and accelerating the overall construction schedule.
Solution Approach 2:
The curing process is skipped or significantly reduced on-site by using precast slabs that have already cured in the plant. The slabs are manufactured with controlled curing conditions and can be installed immediately after leaving the plant, bypassing the time-consuming on-site curing phase.
3Ease of manufacture
If precast slabs are assembled with recessed bolts at the interface, then the slabs can be connected, but local stress concentration occurs near the slab edges
Solution Approach 1:
The connection mechanism is extracted from the slab interface itself and relocated to the column ends. Steel columns are equipped with connection elements that engage with the slabs from the column side, rather than using recessed bolts at the slab edges. This removes the stress concentration problem from the slab interface.
Solution Approach 2:
Steel columns serve as intermediaries between the support structure and the concrete slabs. The columns provide a transition zone with specialized connection elements that distribute loads smoothly, eliminating the need for direct slab-to-slab connections that cause stress concentration at interfaces.
4Shape
If different types of slabs (symmetrical and asymmetrical) are used depending on position, then the building structure can be formed, but the system becomes complex and costly
Solution Approach 1:
A single universal slab design is used for all positions in the building structure. The slabs are designed with standardized dimensions and reinforcement patterns that can be used anywhere in the grid, eliminating the need for different symmetrical and asymmetrical slab types and simplifying the overall system.
Solution Approach 2:
The slab system is made homogeneous by using identical precast concrete slabs throughout the structure. This uniformity simplifies manufacturing, transportation, and assembly operations, reducing complexity and costs associated with managing multiple slab types while still accommodating the building's geometric requirements.
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 solution reduces construction time and costs by minimizing the need for on-site concrete pouring, enhances structural stability and rigidity, and simplifies the assembly process while ensuring the structural frame can withstand various loads and environmental conditions.
Implementation Method 1
a first tendon assembly extending between the first and second columns, the first tendon assembly being adapted to be tensioned to thereby compress the first elongated edge beam between the first and second columns
Implementation Method 2
grout is applied to encase the tendons for added strength and protection
Data Source
AI summary
A structural frame for a building, comprising: adjacent first and second columns; at least one precast concrete floor slab having first and second corner indents located in two adjacent corners and a first elongated edge beam defined between the first and second corner indents, the first elongated edge beam being disposed between the first and second columns such that the first and second columns are received in the first and second corner indents and that the first elongated edge beam abuts the first and second columns; and a first tendon assembly extending between the first and second columns and adapted to be tensioned to compress the first elongated edge beam between the first and second columns, the first tendon assembly including at least one left cable and at least one right cable located symmetrically on either sides of a vertical center plane of the first and second columns.