SEISMIC DESIGN OF CONCRETE BUILDINGS
(Instructor: M. N. Fardis)
The current philosophy of force-based seismic design of buildings for controlled inelastic response and its main instruments: capacity design and detailing of plastic hinge regions for ductility. The trade-off between strength and ductility.
Conceptual design of earthquake-resistant concrete buildings. Main features and conceptual design of frame, wall or dual (frame-wall) building. Conceptual design of building foundation systems for earthquake-resistance. Case histories of buildings with deficient structural configuration in past earthquakes.
Cyclic behaviour of concrete, reinforcing bars and their interaction through bond and in interface shear transfer. Cyclic behaviour of concrete beams, columns, walls and joints: experimental results and examples from past earthquakes. Modeling of cyclic resistance and deformation capacity of concrete members in flexure, shear or flexure-shear combinations at the local and at the element level. Derivation of member detailing rules in Eurocode 8 for a target deformation capacity.
Design of foundation systems and elements in earthquake-resistant buildings.
Introduction to the use of high-performance cement-based materials and polymer composites in new construction: material properties and behaviour, design issues, applications. Review of conventional materials and techniques for member-level and structure-level retrofit of reinforced concrete (RC) and unreinforced masonry (URM) structures. Seismic retrofit with fiber-reinforced polymers (FRP) and cement-based composites: (a) Material properties, application techniques (externally-bonded, near-surface mounted and mechanically-fastened composites), basis of design, retrofitting strategies. (b) Behaviour, mechanics and dimensioning of RC members retrofitted in flexure, shear/torsion and through-confinement. (c) Behaviour, mechanics and dimensioning of URM subjected to in-plane and out-of-plane loading. (d) Detailing, practical execution and quality control, durability. (e) Case studies and design examples.
Introduction to basic problems of soil dynamics and geotechnical earthquake engineering. Review of dynamics of simple oscillators. Wave propagation in one and multiple dimensions. Damping in soils and structures. Seismic site effects. In-situ and laboratory determination of dynamic soil properties. Foundation Vibrations. Design methods for spread footings. Dynamics of piles and pile groups. Soil-structure interaction (SSI). Beneficial and detrimental effects of SSI. Case Studies involving SSI..
- Dynamic loadings of structures. Equation of motion of Single Degree Of Freedom (SDOF) systems for ground excitations. Damping, free and forced vibrations of SDOF systems.
- Brief introduction to earthquakes and to engineering seismology.
(Causes of earthquakes, Earthquake magnitude, intensity, scales. Seismic hazard and risk.)
- Earthquake ground motions, response and design spectra.
- Dynamic Earthquake Analysis of Multi Degree Of Freedom Systems (MDOF) using the method of normal modes for time history and response spectrum solutions.
- Elastic and inelastic structural response, plastic hinge model, ductility, ductility and behavior factors. Principles of earthquake resistant design, modern Codes. Special topics of earhquake resistant structures. New technologies.
(Depending on the students background some topics may not be covered)
The course objectives are to introduce to the students the main concepts of Earthquake Source Mechanics and Elements of the Theory of Elastic Wave Propagation (Elastodynamics) and enable them to understand modern approaches to the problem of Earthquake Strong Ground Motion Prediction and Synthesis, the ultimate objective being assessment of Seismic Hazard for earthquake engineering design.
Topics to be covered include:
Earthquakes and Plate Tectonics; Seismometry; Seismic Waves – Overview; Seismic Source (Important Source Parameters; Source Spectrum; Scaling Laws); Path and Site Effects (including Basin Effects and Topography Effects) – Overview; Prediction and Simulation of Strong Ground Motion (Empirical Approaches; Mathematical Modeling Techniques -- Near-fault vs. Far-field ground motions); Seismic Hazard Assessment for Performance Based Earthquake Engineering; Relevance to Building Codes.
The presentation of the topics is tailored to the needs of earthquake engineers.
The course objective is to familiarize students with the elegant and powerful theory of Random Vibrations of Structural Systems (with finite degrees of freedom) with particular emphasis on the analysis of such systems to earthquake excitations.
Topics to be covered include:
Theory of Random Processes [Specification of Random Processes; Stationary (Homogeneous) Random Processes; Expected Values: Moments; Differentiation and Integration of a Random Process; Spectral Representation of a Random Process; Non-stationary (evolutionary) Random Processes]. Some Important Random Processes [Gaussian, Poisson, and Markov Random Processes]. Further Properties of Random Processes [Threshold Crossings; Peak Distribution; Envelope Distribution; First-Passage Time; Maximum Value of a Random Process in a Time Interval]. Linear Structures with Single Degree of Freedom (SDOF) [System Response to Random Excitation; Weakly Stationary Excitations; Non-stationary Excitations]. Linear Structures with Multiple Degrees of Freedom (MDOF) [General Analytical Framework]. Structural Failures Resulting from Dynamic Response and Related Topics [First-Excursion Failures; Fatigue Failures]. Response of Nonlinear Structural Systems [Method of Equivalent Linearization – Hysteretic Systems]
SEISMIC DESIGN OF STEEL STRUCTURES
(Instructor: D. E. Beskos)
Mechanical properties of steel. Mechanical behavior of steel beams and columns. Behavior of connections. Methods of global analysis. Seismic design and codes. Ductility and behavior factor. Capacity seismic design. Typology of steel structures. Effect of global instability. Effects of diaphragms, semi-rigid connections and axial forces. Foundations. Examples of seismic design of steel structures. Introduction to the next generation of codes. Displacement-based design. Damage controlled design. Use of advanced methods of analysis in seismic design. Force / displacement hybrid seismic design of steel structures.
SEISMIC PROTECTION SYSTEMS FOR STRUCTURES
(Instructor: N. Makris)
Introduction into the traditional seismic design. Strength, ductility, dissipation of energy and seismic isolation. Displacements and forces. The beneficial roles of large flexibility and additional damping. Linear viscoelastic behavior. Linear theory of seismic isolation. Analysis of recordings from seismically isolated structures. Modern regulations about seismic isolation (UBC – SEAONC, FEMA 273 & 274). Mechanical behavior of elastometallic bearings. Mechanical behavior of slip bearings. Mathematical modeling of the mechanical behavior of bearings.
Transition from slippage to the elastoplastic and bi-linear behavior. Seismic vibrations near the fault with distinct pulses of ground acceleration and velocity. Introduction to nondimensional analysis and the effectiveness of seismic isolation from strong earthquakes. Additional (supplemental) damping. Friction dampers, metallic and viscoelastic dampers. Applications in buildings and bridges.
STATIC & DYNAMIC SOIL-STRUCTURE INTERACTION
(Instructor: G. Mylonakis)
Review of basic numerical methods for soil-structure interaction. Simple interaction problems for footings and piles in homogeneous half-space. Finite-element methods for static and dynamic problems. Harmonic analysis. The radiation criterion and transmitting boundaries. Applications to planar and axisymmetric problems involving footings, piles and dams. Spectral elements, Transfer-matrix methods. Applications to stress waves in inhomogeneous media. Boundary elements methods. Soil-Foundation-superstructure interaction under seismic loading. Application examples.