DYNAMIC FIELD TESTING of concrete - Various test
- 1. DYNAMIC FIELD TESTING Structural Health Monitoring And Retrofitting Presenters : Manpreet Singh Bains 2245004 Ujjwaldeep Singh 2245009
- 2. CONTENT 1. • Stress History test 2. • Dynamic load allowance test 3. • Ambient vibration test 4. • Pull back test 5. • Remote data acquisition system
- 3. Structural health monitoring involves continuously monitoring the condition of structures, to assess their health and performance. It can provide valuable insights into its structural integrity and potential for damage or failure. It is commonly done for structures like: INTRODUCTION Buildings Bridges Tower
- 4. Stress history testing involves measuring and analyzing the stress and strain levels experienced by a structure throughout its operational lifespan. Stress history test provides valuable information about the past and current loading conditions experienced by a structure. Done using various sensors and monitoring devices placed on or within the structure to collect data on its response to external loads or environmental conditions. Collected data is analyzed to assess the stress and strain history of the structure, which provides information about behavior, performance and potential for deterioration. STRESS HISTORY TEST
- 5. Methods of Stress History Test Method 1 Strain sensors Method 2 Simulation METHODS OF STRESS HISTORY TEST
- 6. This test is done using of strain sensors such as strain gauges or fiber optic sensors, which are attached to a structure at definite locations. External loads or environmental conditions Strains experienced Stress history obtained Issues identified Service life estimated PROCESS METHOD 1 (STRAIN SENSORS)
- 7. STRAIN GAUGE
- 8. Use of simulation techniques, with Finite element analysis and other computational methods are used to simulate the stress and strain behavior of a structure under various loading scenarios. With this stress history of the structure and prediction of its response to different conditions is done. Structure model with loading Simulation Analysis method Stress history obtained Issues identified Maintenance or Repair PROCESS METHOD 2 (SIMULATION)
- 10. The dynamic load allowance test is a type of test that is performed on a structure to determine its ability to withstand varying loads and forces over time. This test is usually conducted to evaluate the durability and strength of a structure subjected to dynamic loads, such as vibration, impact, or shock. During the test, the structure is loaded with dynamic loads that are applied in a controlled manner. The loads may be applied using hydraulic actuators, mechanical shakers or moving trucks. The loads are applied in a way that simulates the actual conditions that the structure or equipment will experience during operation. DYNAMIC LOAD ALLOWANCE TEST
- 11. Dynamic load allowance = 𝟓𝟎 𝑳+𝟏𝟐𝟓 where L = the length (feet) of the portion of the span that is loaded The American Association of State Highway and Transportation Officials (AASHTO) recommends using 33% as a maximum value of DLA
- 12. Three types of test vehicles are utilized: i. Empty dump truck ii. Full dump truck iii. Semi-truck One passage is conducted for each type of loading scenario. Each test vehicle moves at speed : i. Crawl speed ii. 10 mph iii. 20 mph iv. 30 mph v. 50 mph
- 13. LOAD TRUCKS Dump truck Semi truck
- 14. • Types of loads and forces, duration of the test Define the test criteria • Strain gauges, accelerometers, and load cells. Instrumentation • Subjected to varying loads and forces over time. Apply loads and forces • Response of structure on loading or applying forces. Monitor performance • Loads and forces that structure was able to withstand without failure. Evaluation • Improvements or maintenance Conclusion STEPS INVOLVED
- 15. The ambient vibration testing procedure consists of real time recording of the vibrations and processing of the records. This method is based on measuring the small structural vibrations caused by the ambient forces. Ambient forces may be caused by the wind, human activities, traffic or some other micro-tremor. Natural frequency of a structure is found in order to keep the structure safe. If natural frequency matches to that of frequency due to external forces, resonance will come into play. AMBIENT VIBRATION TEST
- 16. Ambient forces Vibrations Motion detected by accelerometers Data of vibration stored Issue detected PROCESS Resonance will increase the magnitude of vibration to such an extent, that will cause severe damage. Accelerometers are placed at specific locations to monitor structure’s response.