FRP Joint Strengthening with Filler Module
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Solution Overview
Problem
Current methods for strengthening structural joints using discontinuous fiber-reinforced polymer (FRP) sheets are inefficient in absorbing shocks and minimizing stress concentrations, leading to potential delamination, shear failure, and premature failure under dynamic and environmental loads, due to improper application and material limitations.
Innovation Solution
A system comprising a filler module and a continuous wrap material applied in a specific configuration to minimize stress concentrations, enhance strength, stiffness, and energy absorption, with optional dowels and an outer fabric layer for confinement and fire resistance, designed to address the unique loads and geometries of each joint.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If discontinuous fiber-reinforced polymer sheets are applied in a haphazard manner to strengthen joints, then material application becomes simpler, but stress concentration is not minimized and shock absorption is reduced
Solution Approach 1:
The joint strengthening system is segmented into multiple functional layers: base layer, intermediate layer with specific fiber orientation, and outer layer. Each layer serves a specific function in stress distribution and shock absorption, replacing the haphazard single-layer application with a structured multi-layer configuration.
Solution Approach 2:
The fiber orientation and material properties are optimized locally at different positions around the joint. The intermediate layer uses fibers oriented at specific angles (e.g., 45 degrees) to addresses stress concentration at re-entrant corners, while other layers have different orientations to handle various stress components.
2Device complexity
If multiple sheets of FRP are wrapped about a joint without confinement, then material usage becomes simpler, but rupture stress resistance is not maximized
Solution Approach 1:
The system uses composite material construction with FRP sheets combined with a confinement mechanism. The confinement element (such as a steel plate or additional FRP layer) works together with the wrapped sheets to create a composite structure that maximizes rupture stress resistance through combined material properties and geometric configuration.
3Productivity
If FRP sheets are bonded with epoxy adhesives without proper curing control, then application process becomes faster, but long-term integrity is compromised
Solution Approach 1:
Surface preparation and adhesive application are performed as preliminary actions before sheet installation. The substrate is properly cleaned, roughened, and primed in advance to ensure optimal adhesive bonding. This preliminary preparation ensures long-term integrity while maintaining efficient application speed.
4Ease of manufacture
If steel angles with sharp edges are placed at joints, then structural connection becomes simpler, but cracking occurs at sharp edges under load
Solution Approach 1:
Sharp edges of steel angles are replaced with curved or rounded transitions. The FRP wrapping creates a smooth continuous reinforcement that eliminates stress concentration at sharp corners. This curvature approach maintains connection simplicity while preventing edge cracking under load.
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
Significantly increases the strength, ductility, and energy absorption capacity of joints, reducing the risk of material deterioration and failure under dynamic and environmental loads, with test results showing a 3-8 times increase in load-bearing capacity compared to un-reinforced joints.
Implementation Method 1
maximizing the rupture stress resistance of the materials through confinement and damping
Implementation Method 2
the module is designed and configured to dissipate energy from a load applied to the structure
Implementation Method 3
multiple sheets/strips of FRP are wrapped about a joint, using epoxy or other adhesives
Data Source
AI summary
The disclosed technology is a system and a method for strengthening one or more joints of a structure having a plurality of structural members forming a vacuous area at each joint. The method includes computing limit load bearing capacity for the structure, at a joint, securing a filler module to the joint, at the vacuous area, the filler module having a plurality of surfaces so that when secured within the vacuous area, some of the surfaces are tangential to the members of the structure at its joint, and one or more of the surfaces are non-tangential to the members of the structure, and applying at least one layer of continuous fiber reinforced polymer wrap about the filler module and the members at the joint. The filler module of the disclosed technology is designed and configured to dissipate energy from a load applied to the structure, and at least doubling the load bearing capacity for the structure, at the joint.