How can you conduct a comprehensive structural analysis before and after retrofitting?

1 Preliminary inspection

The first step is to inspect the structure visually and document its geometry, materials, defects, damages, and environmental conditions. You should also collect any available information about the design, construction, and maintenance history of the structure. This will help you to understand the original and current performance of the structure, as well as the causes and extent of deterioration or distress.

2 Non-destructive testing

The next step is to perform non-destructive testing (NDT) to measure some physical properties of the structure, such as strength, stiffness, density, moisture, corrosion, cracks, and defects. NDT methods are fast, easy, and economical, and they do not damage the structure or affect its serviceability. Some common NDT methods are rebound hammer, ultrasonic pulse velocity, infrared thermography, ground-penetrating radar, and acoustic emission.

3 Destructive testing

Sometimes, you may need to perform destructive testing (DT) to obtain more accurate and reliable information about the structure, such as material composition, mechanical properties, and damage mechanisms. DT methods involve removing samples or cores from the structure and testing them in a laboratory or on-site. However, DT methods are costly, time-consuming, and invasive, and they may weaken the structure or create new defects. Therefore, you should use DT methods sparingly and carefully.

4 Numerical modeling

After collecting the necessary data from the inspection and testing, you can create a numerical model of the structure using software tools such as finite element analysis (FEA), discrete element method (DEM), or agent-based modeling (ABM). A numerical model is a mathematical representation of the structure that simulates its behavior under various loads and conditions. You can use a numerical model to analyze the structural response, identify the critical regions, and predict the failure modes and mechanisms.

5 Retrofitting design

Based on the results of the numerical model, you can design a suitable retrofitting technique to improve the structural performance, safety, and durability. Retrofitting techniques can be classified into three categories: strengthening, repairing, and upgrading. Strengthening techniques increase the load-carrying capacity and stiffness of the structure, such as fiber-reinforced polymer (FRP) wrapping, steel jacketing, or prestressing. Repairing techniques restore the original condition and functionality of the structure, such as patching, grouting, or epoxy injection. Upgrading techniques enhance the resistance and resilience of the structure to extreme events, such as seismic isolation, energy dissipation, or base isolation.

6 Post-retrofitting analysis

The final step is to perform a post-retrofitting analysis to verify the effectiveness and efficiency of the retrofitting technique. You can use the same methods and tools as in the pre-retrofitting analysis, such as inspection, testing, and numerical modeling. However, you should also consider the compatibility, durability, and sustainability of the retrofitting technique with the existing structure and the environment. You should also monitor the performance and behavior of the retrofitted structure over time using sensors, instrumentation, or smart materials.

7 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?