Side-loaded FRP Wrap for Reinforced Concrete Piling Rehabilitation
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Solution Overview
Problem
Reinforced concrete pilings in saltwater environments are prone to degradation due to corrosion of steel rebar, leading to structural integrity failures, which are costly and difficult to maintain, especially when traditional replacement methods are impractical.
Innovation Solution
The use of a basalt fiber reinforced polymer (BFRP) apparatus and method for rehabilitating concrete pilings, providing a non-metallic, corrosion-proof wrap that evenly distributes loads and aligns with the piling, using continuous basalt fibers with a thermoset bio epoxy matrix, which is lightweight, durable, and resistant to corrosion and water absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If steel rebar is used to reinforce concrete pilings, then tensile strength is improved, but corrosion resistance deteriorates due to moisture wicking through porous concrete
Solution Approach 1:
The patent applies parameter changes by transforming the steel rebar into FRP (fiber reinforced polymer) rebar, changing the material parameters from metallic to polymer-based composite. This substitution maintains the tensile strength function while eliminating the corrosion vulnerability, as FRP materials do not undergo electrochemical corrosion in saltwater environments.
Solution Approach 2:
The patent employs composite materials by using FRP (fiber reinforced polymer) instead of traditional steel rebar. The FRP composite consists of polymer matrix and reinforcing fibers, providing both the necessary tensile strength and corrosion resistance. This composite material approach resolves the contradiction by combining the benefits of high strength with immunity to galvanic corrosion.
2Reliability
If concrete pilings are replaced when degraded, then structural integrity is restored, but cost and complexity increase due to superstructure removal requirements
Solution Approach 1:
The patent applies preliminary action by proactively replacing degraded steel rebar with corrosion-resistant FRP rebar before complete failure occurs. This preventive reinforcement restoration maintains structural integrity while avoiding the need for full piling replacement, thereby reducing the complexity of superstructure removal and reinstallation.
Solution Approach 2:
The patent extracts only the degraded steel rebar component from the piling structure and replaces it with FRP rebar, rather than replacing the entire piling. This selective component replacement approach restores structural integrity while minimizing disruption to the superstructure and reducing overall replacement complexity.
3Reliability
If wood pilings are used instead of steel reinforced concrete, then corrosion resistance is improved, but durability deteriorates due to wood rot and marine infestation
Solution Approach 1:
The patent uses FRP (fiber reinforced polymer) composite materials that combine the corrosion resistance of polymers with the structural strength of reinforcing fibers. This composite approach provides both the corrosion resistance needed to withstand saltwater environments and the durability required for long service life, overcoming the limitations of both wood and traditional steel.
Solution Approach 2:
The patent applies parameter changes by selecting materials with specific properties: FRP rebar provides non-corrosive, rot-resistant, and structurally sound characteristics. This material parameter selection achieves both high corrosion resistance and extended service life, eliminating the trade-off present between wood and steel options.
4Adaptability or versatility
If rebar is cut to fit specific applications, then adaptability is improved, but corrosion resistance deteriorates due to exposed ends becoming moisture ingress points
Solution Approach 1:
The patent applies parameter changes by utilizing the inherent properties of FRP materials that can be cut and shaped without creating corrosion vulnerabilities. Unlike steel, FRP cutting edges do not create galvanic corrosion sites, allowing full adaptability for custom applications while maintaining corrosion resistance. The material parameters of FRP enable cutting operations without compromising the protective properties.
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
Extends the service life of steel reinforced concrete structures by preventing corrosion and structural damage, allowing for in-place rehabilitation without disturbing supported structures, reducing maintenance costs, and ensuring the piling can withstand higher loads and harsh environments.
Implementation Method 1
a first wrap of fiber reinforced polymer (FRP) material is placed around said pilings... said FRP material prevents corrosion and structural damage
Implementation Method 2
continuous basalt fibers with a thermoset bio epoxy matrix
Implementation Method 3
The use of a basalt fiber reinforced polymer (BFRP) apparatus and method for rehabilitating concrete pilings, providing a non-metallic, corrosion-proof wrap that evenly distributes loads
Implementation Method 4
lightweight, durable, and resistant to corrosion and water absorption
Data Source
AI summary
A method of rehabbing reinforced concrete pilings while in service and without the requirement to demo or otherwise gain access over the ends of an existing column. Design adopts modern environmentally responsible fiber reinforced polymer rebar and other FRP stirrups uniquely shaped into spiral sections requiring only side access for placement, designed to permanently encase the piling with a totally non-rusting non-metal reinforcement lateral containment cage featuring preformed circumference stirrups that mechanically interlock vertically and lateral adjustability to control density. The spiral stirrups extending fully 360-degrees around an existing piling with an additional overlap of at least 45 degrees.