B8862 - MONITORAGGIO E CONTROLLO DELLE STRUTTURE E DELLE INFRASTRUTTURE M

Learning outcomes

With this course, students acquire the theoretical and practical knowledge fundamental to perform high-precision surveys, aimed at the static control and testing of civil structures and infrastructures. Both traditional topographic methodologies and the most modern technologies available (GNSS – InSAR) will be considered. Particular attention will be paid to theoretical and practical design aspects, including consideration of statistical tests of displacement detections. Part of the course is dedicated to practical laboratory work in the field of Geomatics.

Course contents

Recommended Prerequisite Knowledge

Students enrolling in this course are expected to have a basic understanding of the following topics:

• Fundamentals of Applied Geodesy: local, national, and international reference systems.
• Operating principles of conventional surveying instruments: theodolites, electronic distance meters (EDMs), levels, automatic levels, and total stations.
• Knowledge of traditional topographic surveying techniques: intersection methods, traverse surveys, and differential geometric leveling.
• Understanding of the operating principles of Global Navigation Satellite Systems (GNSS).
• Fundamentals of the statistical treatment of observations: expected value, variance, covariance, and variance propagation in nonlinear multivariable functions.
• Basic knowledge of Mathematics and Geometry: trigonometry, derivatives and partial derivatives, and integral calculus.

These prerequisites are normally acquired by successfully completing a Topography course within the Italian Scientific Disciplinary Sector ICAR/06 (6–12 ECTS credits).

Course Contents 1. Review and Integration of Geodesy 2. Review and Integration of Traditional Surveying Methods 3. Main Reference Systems and Reference Surfaces Used in Geomatics

• Reference systems and reference frames
• Local geodetic systems
• Local reference systems: description, objectives, characteristics, and implementation for structural monitoring purposes

4. Fundamentals of Structural Monitoring

• General framework of the monitoring problem
• Theoretical and operational aspects of monitoring networks
• Types of entities to be measured
• Surveying measurements for monitoring structural movements and deformations, including testing and acceptance procedures for structures and infrastructures

5. Specific Applications

Topographic surveys for:

• Load testing of simply supported beams
• Testing and monitoring of bridges and viaducts, including simply supported beam bridges and continuous beam or slab bridges
• Testing of large mushroom-roof reservoir slabs
• Verticality control
• Monitoring of structures located in landslide-prone areas
• Monitoring and surveillance of dams

6. Review and Advanced Topics in the Statistical Adjustment of Observations

• Variance–covariance propagation in nonlinear multivariable functions
• Least Squares Adjustment using the indirect observation model:
  • minimally constrained adjustment,
  • over-constrained adjustment,
  • free network adjustment (main differences)
• Statistical properties of parameter estimates
• Applications of indirect observation adjustment to topographic surveys
• Data processing workflow: free-network adjustment, constrained adjustment, and network realization
• Height networks, planimetric networks, three-dimensional engineering networks, and GNSS networks
• Advanced analysis of adjustment results
• Quality assessment of observations:
  • observation–residual relationships,
  • gross error detection,
  • local redundancy analysis
• Statistical significance testing of displacements:
  • repeated surveys,
  • minimum detectable displacement,
  • significance testing of positional changes

7. Specialized Monitoring Instruments

Overview of specialized instruments particularly suited for structural monitoring, complementing conventional surveying equipment.

8. Advanced Differential Geometric Leveling

• High-precision differential geometric leveling
• Technical standards
• Tolerances and best surveying practices

9. Advanced GNSS Positioning Techniques

• Surveying methodologies and systematic error modeling
• Static GNSS surveying
• Post-Processed Kinematic (PPK) surveying
• Real-Time Kinematic (RTK) surveying
• Permanent GNSS reference stations (CORS)

10. Time Series Analysis

Theoretical and practical aspects of processing geodetic time series for estimating the main characteristics of the observed signal and the automatic detection and removal of outliers.

11. Introduction to SAR Interferometry

Basic principles of Synthetic Aperture Radar (SAR) Interferometry for the monitoring of structures and transportation infrastructures.

Readings/Bibliography

The teacher upload the personal notes on Virtuale.unibo.it Web pages.

Teaching methods

The course is composed by frontal lessons, practice (outdoor and in laboratory) and a couple of educational trips.

In particular the course is generally composed by:

• 70% of frontal lessons
• 20% of practice (outdoor and in laboratory)
• 10% of educational trips

Assessment methods

The exam consist in a oral discussion that start from a real case of structure monitoring or land monitoring.

Will be analized the topographic survey techniques, survey methodologies and capability to detect a movement starting from the design of monitoring system.

The evaluation will be based on different aspect related to:

1) capability to identify the best methods and instrumentations for the case study

2) Knowledge of the methods and tecniques usefull for the case study

3) Capability to apply statistical tests for minimum movement detection.

4) Capability to estimate the real accuracy obtained by a topographical survey using the statistical law of the variance/covariance propagation in non linear multidimensional functions

Teaching tools

In order to support the classical frontal lessons in the classroom, some practical exercises will be performed both in outdoors and in the laboratory. Moreover some guided tours will be perfomed.

In particular:

Practices (outdoor)

• Survey of a small network using spirit leveling.
• Survey of a geodetic network using GPS static approach.
  

Data analysis (laboratory)

Data Processing of the acquired data during the practices (in outdoor)

Guided Tours Dam:

• Ridracoli
  

During the practices very high precision surveying instruments will be provided. Laboratory are equipped with specific software packages for dataprocessing and analysis of data

Office hours

See the website of Stefano Gandolfi