R E S E A R C H
Hazard Assessment
Civil engineers must assess in quantitative terms the consequences of failure of constructed
facilities due to the action of natural hazards: wind storms, earthquakes, floods and
tsunamis. Failures induced by man-made hazards must be considered as well. Analysis
of failure consequences must address a broad range of issues: life safety, injury,
potential economic losses, societal impact, and environmental impact. Hazard assessment,
lifetime cost and performance, and failure scenarios are critical elements of
decision-making in the face of uncertainty and limited resources. The
Department is
conducting a number of studies in the hazard assessment and mitigation areas.
Probabilistic Modeling of Engineered Facilities
Performance and reliability of engineered facilities are impacted by uncertainties
associated with their design and operation. Stochastic methods are required to model
natural hazards, such as winds and earthquakes, and other loads. Structural aging and
quality control of materials, design and fabrication, along with modeling uncertainty,
are being incorporated in reliability studies. Large-scale system reliability techniques
and mathematical programming are being applied to optimize the design process for complex
structural systems. Probabilistic risk assessment procedures are being used to quantify
the consequences of postulated extreme events. Probability-based structural design codes
allow limit states of structural members and systems to be formulated using principles
of structural mechanics and probabilistic models of uncertain load and strength variables.
Structural Dynamics
All structures are subject to environmental loads that are dynamic. Wind, waves,
earthquakes, explosions, and traffic all initiate dynamic structural responses that affect
structural safety, serviceability, and durability. Within structural dynamics, the tools of
analysis are more extensive than those concerned with statics alone, encompassing the
disciplines of fluid and solid mechanics, linear and nonlinear structural behavior,
stochastic methods, and their mathematical representations. Particular research thrusts
in the Department are centered around the response of structures to earthquakes and the
understanding of the aerodynamics and aeroelasticity of long-span bridges under wind
forces. Measurement systems, including appropriate data transmission
and analysis frameworks, are implemented to advance the understanding of structural
performance under service loadings.
Computational Mechanics
The future of computational mechanics lies in the integration of more complex material
models, more efficient algorithms, and new computer architectures to model phenomena
occurring in diverse fields more realistically. The algorithms used to solve complex
problems need to be refined to better utilize available resources. As newer analytical
techniques and computer software and hardware become available, the integration of
classical mechanics insights with the complementary techniques of advanced numerical
modeling requires constant attention and upgrading. Concepts developed in other fields
may provide alternatives in tackling complex engineering problems that conventional
mechanics cannot address.
Geomechanics
The geotechnical engineering research program focuses on fundamental principles of
mechanics, supported by computational methods and laboratory testing. Several specific
aspects are being addressed: fundamental understanding of behavior of clays and sands
at both microscopic and macroscopic levels; accurate constitutive models for predicting
the stress-strain behavior of soils and composite geomaterials; improved numerical
procedures for the nonlinear analysis of complex, plane and three-dimensional, static and
dynamic problems of soil-structure interaction and earth structure stability; and
advanced experimental testing and digital imaging to evaluate strain
localization in granular soils.
Current research efforts are driven by the need to address important geotechnical issues
such as design for earthquake loads and introduction of new materials.