Unit 1993: Structural Dynamics and Earthquake Engineering

1. Introduction to Structural Dynamics

• Overview of structural dynamics
• Importance in engineering applications
• Fundamental concepts: dynamic loading, inertia, damping, stiffness
• Types of dynamic loads: environmental, operational, accidental

2. Single Degree of Freedom (SDOF) Systems

2.1 Mass-Spring-Damper Models

• Components and physical interpretation
• Equation of motion derivation

2.2 Free Vibration

• Undamped and damped free vibration
• Natural frequency and damping ratio

2.3 Forced Vibration

• Harmonic excitation
• Steady-state response and transient response

2.4 Resonance and Response Analysis

• Definition and implications of resonance
• Amplitude magnification factor
• Phase relationships

3. Multiple Degree of Freedom (MDOF) Systems

3.1 System Modeling and Equations of Motion

• Mass, damping, and stiffness matrices

3.2 Modal Analysis

• Concept of modes and mode shapes
• Natural frequencies calculation

3.3 Mode Superposition Method

• Decoupling equations of motion
• Modal participation factors

4. Structural Modeling for Dynamic Analysis

4.1 Lumped Mass Models

• Assumptions and applications

4.2 Finite Element Models

• Element types for dynamic analysis
• Assembly of global matrices

4.3 Boundary Conditions for Dynamic Problems

• Fixed, pinned, and elastic supports
• Influence on natural frequencies and mode shapes

5. Dynamic Response of Structures

5.1 Time-Domain Analysis

• Numerical integration methods (e.g., Newmark-beta, Wilson-theta)
• Response history analysis

5.2 Frequency-Domain Analysis

• Fourier transform and spectral analysis

5.3 Effects of Damping and Stiffness

• Types of damping: viscous, hysteretic
• Impact on response amplitude and phase

6. Earthquake Engineering and Seismic Design

6.1 Earthquake Ground Motions

• Characteristics and measurement

6.2 Seismic Response Spectrum Analysis

• Construction and interpretation of response spectra

6.3 Seismic Design Codes and Regulations

• Overview of major codes (e.g., IBC, Eurocode 8)

6.4 Earthquake-Resistant Design Strategies

• Base isolation, ductility, energy dissipation systems

7. Wind Engineering and Dynamic Wind Loads

7.1 Wind Load Calculations

• Basic wind speed, pressure, and force determination

7.2 Dynamic Wind Effects on Tall Buildings

• Vortex shedding and buffeting
• Aeroelastic phenomena

7.3 Mitigation Strategies for Wind-Induced Vibrations

• Aerodynamic modifications
• Structural damping and mass dampers

8. Vibration Control and Mitigation

8.1 Passive Control Systems

• Tuned mass dampers, base isolators

8.2 Active Control Systems

• Feedback mechanisms and actuators

8.3 Hybrid Control Systems

• Combination of passive and active methods

8.4 Vibration Isolation Techniques

• Isolation pads, mounts

9. Nonlinear Dynamics of Structures

9.1 Nonlinear Response Characteristics

• Geometric and material nonlinearities

9.2 Limit Cycles and Stability

9.3 Chaos and Bifurcation Phenomena

• Definitions and structural implications

10. Experimental Modal Analysis

10.1 Principles of Modal Testing

• Instrumentation and excitation methods

10.2 Modal Parameter Estimation

• Natural frequencies, damping ratios, mode shapes

10.3 Correlation with Analytical Models

• Validation and updating of numerical models