Corrosion-Fatigue Coupled Test for Steel Bridge Decks
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Solution Overview
Problem
Current structural performance test devices for orthotropic steel bridge decks primarily consider the effect of a single factor, either corrosion or fatigue, failing to accurately simulate the coupling effect of corrosion and fatigue, which significantly reduces the service life of these structures.
Innovation Solution
A corrosion-fatigue-coupled test method and device that simulates the real atmospheric environment by using a full-scale model of a segmented orthotropic steel bridge deck with fiber Bragg grating sensors, alternating dry-wet immersion with a 3.5% sodium chloride solution, and controlled fatigue loading to accurately model the corrosion and fatigue degradation mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single-factor test (corrosion or fatigue) is used, then the test setup is simple, but the test accuracy in simulating real service environment is insufficient
Solution Approach 1:
The patent merges corrosion testing and fatigue testing into a single coupled test system. The test device simultaneously applies corrosive environment (salt spray chamber) and cyclic fatigue loading to the bridge deck specimen, enabling comprehensive simulation of real-service conditions where both corrosion and fatigue act together. This integration resolves the contradiction by accepting increased device complexity to achieve accurate multi-factor simulation.
Solution Approach 2:
The test device is designed with multi-functionality to perform both corrosion exposure and fatigue loading operations. The system includes a salt spray chamber for corrosion testing, a fatigue loading system with hydraulic actuators, and integrated data acquisition systems that can monitor both corrosion progression and mechanical response. This universal design allows a single test setup to replace multiple separate tests, improving simulation accuracy while managing complexity through functional integration.
2Measurement precision
If real-time monitoring of stress performance and crack propagation is implemented, then the data accuracy is improved, but the device complexity increases
Solution Approach 1:
The patent replaces traditional mechanical measurement systems with optical fiber-based sensing technology. Fiber Bragg grating (FBG) sensors are embedded in the bridge deck specimen to monitor strain, stress, and crack propagation in real-time. These optical sensors provide high-precision measurements without adding mechanical complexity to the loading system, and their distributed sensing capability enables simultaneous monitoring at multiple locations along the specimen.
Solution Approach 2:
The patent uses fiber optic sensing to create a distributed measurement network that effectively 'copies' the structural response at multiple points simultaneously. The FBG sensors act as distributed sensors along the specimen length, providing real-time data on strain and crack development without requiring physical access or complex mechanical instrumentation at each measurement point. This copying approach enables comprehensive monitoring while maintaining system simplicity.
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 approach effectively simulates the coupling effect of corrosion and fatigue, providing reliable and accurate test data that closely resembles the actual service environment, allowing for a better understanding of the deterioration mechanism and enabling a more accurate time-varying evaluation of structural properties.
Implementation Method 1
arranging a fiber Bragg grating (FBG) sensor to monitor a stress, a temperature and a chloride ion concentration in the weld seam area
Implementation Method 2
The corrosion and fatigue degradation mechanism of the OSBD is as follows: 1. Deterioration of OSBD caused by chloride ions. In the welded structure of the OSBD, the steel bridge deck and the longitudinal stiffeners and diaphragms are connected by a large number of weld seams. Due to welding defects, the chloride ions on the surface of the weld seam penetrate into the weld seam and spread around.
Implementation Method 3
An anode is formed where the passivation film is damaged, and a cathode is formed where it is not damaged, thereby producing a corrosion cell to cause corrosion of the OSBD. The anode metal iron is oxidized to yield iron ions
Implementation Method 4
Under the direct action of the traffic load, the weld seams at the weld joints of the OSBD are prone to structural damage. The corrosion and fatigue-induced failures of the OSBD are fatigue fractures caused due to the coupling effect of the alternating stress and corrosive medium.
Data Source
AI summary
The present invention relates to a corrosion-fatigue-coupled test method and device for a steel bridge deck. The method includes: 1) installing an orthotropic steel bridge deck (OSBD) and pasting filter paper; 2) installing a sodium chloride solution delivery pipe; 3) installing an infrared (IR) lamp; 4) preparing a corrosive solution; 5) coupling corrosion and fatigue; and 6) acquiring test data. A device constructed by using the method includes a to-be-tested OSBD, a support device, a pressure pump, a water tank, a monitoring device, an IR lamp, a plastic water pipe, a thermostat and a rotary sprayer. The present invention solves the problem of laboratory accelerated corrosion of the OSBD. The present invention fully considers a coupling effect of a corrosive medium and an alternating stress, so that the created simulation environment is close to a service environment of the OSBD, and the test data are effective and reliable.