Suggestion Box

Research Highlights

Building System Performance During Earthquakes & Post-Earthquake Fire

Professors Tara Hutchinson, Joel Conte, and Jose Restrepo

Doctoral students Rodrigo Astroza, Michelle Chen, Hamed Ebrahimian, Steve Mintz, Elide Pantoli, and Xiang Wang

This landmark project centers upon the earthquake and post-earthquake fire testing of a five-story building built at full-scale. The building is completely furnished with nonstructural components and systems (NCSs), including a functioning passenger elevator, stairs, partition walls, cladding and balloon framing systems, piping, HVAC, ceiling, sprinklers, building contents, as well as passive and active fire systems.

Column Reinforcement Extended into Enlarged (Type II) Shafts

Professor P. Benson Shing

In spite of recent changes, the seismic design specifications of the California Department of Transportation (Caltrans) on the development of longitudinal column reinforcement in enlarged (Type II) CIDH shafts are still very conservative. For large-diameter bridge columns, #14 and 18 bars are common. With the older specifications that were recently replaced, these large-diameter bars would call for very long development lengths, which could significantly drive up the construction costs.

Soil-Structure Interaction and Performance-Based Earthquake Engineering

Professor Ahmed Elgamal

Three-dimensional (3D) nonlinear finite element simulations are becoming increasingly feasible for geotechnical applications. OpenSeesPL, created by J. Lu, A. Elgamal, and Z. Yang, is a versatile framework that uses a Windowsbased graphical-user-interface (GUI) developed for 3D footing/pile-ground interaction analyses. Various ground modification scenarios may be addressed utilizing the 3D tool. Building on OpenSeesPL, a new GUI has been developed to combine nonlinear dynamic time history analysis of coupled soil-structure systems with an implementation of performance-based earthquake engineering (PBEE) for a single-column 2-span bridge configuration (research with Prof. K. Mackie, UCF).

Wide Area Blunt Impact on Composite Aircraft Structures


Professor Hyonny Kim

The largest source of damage to a commercial aircraft is caused by accidental contact with ground service equipment (GSE). The cylindrical bumper typically found on GSE distributes the impact load over a large contact area, possibly spanning multiple internal structural elements, which can lead to widespread damage that is difficult to visually detect, particularly for resilient composite fuselage skin. To better understand internal damage formation versus visual detectability, stiffened composite panels of various size and complexity have been tested at UCSD's Powell Labs.

Seismic Testing of Full-Scale MSE Retaining Walls

Professors Patrick Fox and Ahmed Elgamal

Retaining wall systems constitute an integral and ever-growing component of our nation's infrastructure, much of which is vulnerable to strong seismic activity. Mechanically Stabilized Earth (MSE) walls are earth retaining structures composed of facing elements, tensile reinforcement, and backfill. Prof. Patrick Fox and co-PI Prof. Ahmed Elgamal will conduct landmark seismic tests of MSE walls on a scale never before achieved.

Hydraulic/High Pressure Nitrogen Based Blast Simulator

Professor Gilbert A. Hegemier

The UC San Diego blast simulator characterizes the response of civilian and military components and systems to terrorist explosive attack and high impact scenarios. It identifies threat mitigation and hardening optimization strategies using both retrofit and new construction methods and materials.

The hydraulic/high pressure nitrogen based blast simulator simulates full-scale explosive loads up to 12,000 psi-msec without live explosives and without a fireball permitting structural responses to be seen as they occur.

Biomimetic Investigation of Fish-Like Propulsion

Professor Qiang Zhu

Inspired by the efficient locomotion of fish, insects, and other creatures, innovative ocean vehicles that imitate animal propulsion and maneuvering are now being developed. This requires a multi-disciplinary effort involving unsteady fluid dynamics, structural mechanics, autonomous sensing and control, shipbuilding technology, as well as advanced materials.

UC San Diego researchers are developing state-of-the-art computer models to help us understand the underlying fluid-structure interactions in the locomotion of aquatic animals.

Optimal Damage Detection and Prognosis Vis Elastic Stress Wave Scattering

Professor Michael Todd

Ultrasonic guided wave interrogation using both coherent-phase arrays and sparse arrays (sparsity defined as arrays whose average sensor-to-sensor distance is significantly longer than the interrogating wavelengths) has evolved into a very active research area. This research focuses on the detection, classification, and prognosis of damage using elastic waves as the interrogation mechanism.

The novel approach in this work is the embedding of stochastic models to account for uncertainty of model/physical parameters, in order to derive an optimal detection process that supports predictive modeling with quantified uncertainty.

Sources of Error in Finite Element Simulations of Effects of Blasts on the Human Brain

Professor Petr Krysl

Recent military conflicts have resulted in an increase in the number of blast related traumatic brain injuries. The present project examines the mechanical effects in a brain impinged upon by a blast wave as simulated by a finite element coupled fluid-solid framework. Various sources of errors were assessed and conclusions are (a) the least important source of error was the assumption of linear kinematics and linear constitutive equation; (b) the discretization error was significant, and controlling it will remain a challenge; and (c) the most significant source of error was found to be the uncertainty of the input parameters (experimental variability) and the lack of knowledge of the detailed micro-mechanics of deformation of the brain tissues under conditions of blast loading.

Battle of Anghiari Project: The Search for Leonardo da Vinci's Lost Masterpiece

Professors Falko Kuester and Maurizio Seracini

Leonardo da Vinci's mural, The Battle of Anghiari, has not been seen in nearly 500 years. It was painted in the Palazzo Vecchio's Hall of the 500, and disappeared when the hall was remodeled by Giorgio Vasari starting in 1563. Was Anghiari destroyed? Or did Vasari build a brick wall in front of Leonardo's work before painting his own fresco over it? IGERT-TEECH PI Falko Kuester and co-PI Seracini undertook detailed LIDAR and multispectral scans of the Hall of the 500 to produce a detailed, 3D computer model to aid in the search-and-discovery effort, and graduate students affiliated with the Center of Interdisciplinary Science for Art, Architecture and Archaeology (CISA3) spent extended periods of time in Florence.

Vibration Suppression and Damage Detection in Wind Turbine Blades


Professor Francesco Lanza di Scalea

The performance of a wind turbine is driven, among other factors, by structural fatigue experienced due to wind-induced vibrations. Under National Science Foundation funding, UCSD is studying a system for mitigating the blade vibrations by using a network of piezo-composite transducers with both active (feedback) and passive (shunt) controls. This system has the potential to increase the fatigue life of the wind turbine system by reducing the vibrations during operation.

Large Deformation Isogeometric Structural Analysis

Professor David Benson

Traditional finite element methods use low degree, piecewise continuous polynomials to model the geometry of a structure. Modern computer aided design uses non-uniform rational B-splines (NURBS) to represent the geometry of a structure exactly. Isogeometric analysis is an extension of the finite element method that also uses NURBS and related functions. Among the advantages are few equations to solve than traditional finite element methods combined with better accuracy.

Seismic Performance and Design of Metal Building Moment Frames

Professor Chia-Ming Uang

Metal Building Systems, which represent a large portion of low-rise construction in the United States, are typically composed of steel moment frames and slender tapered beam sections. To answer questions concerning frame behavior in large seismic events, three full-scale frames were tested on the UCSD/NEES Large High Performance Outdoor Shake Table. Based on their observed behavior, two new seismic force resisting systems are in development. To assess the collapse reliability of the new systems, large parametric studies are being conducted.

Remaining Fatigue Life Predictions of Monitored Structural Systems

Professors Joel. P Conte and John B. Kosmatka

UC San Diego has developed a methodology for predicting and updating the Remaining Fatigue Life (RFL) of monitored aerospace structures and/or structural sub-components. According to this framework, NDE inspection results and Bayesian inference are used to (a) assess the current state of damage of the system and (b) update the probability distribution functions of the damage extents and damage evolution model parameters.

Large-Scale Validation of Seismic Performance of Bridge Columns

Professor José I. Restrepo, UCSD

Professor Stephen Mahin, UCB; Professor Ian Buckle, Univ. of Nevada, Reno

A full-scale, circular reinforced concrete bridge pier designed in accordance to Caltrans' Seismic Design Criteria and Bridge Design Specifications guidelines has been tested under seismic excitation on the NEES-UCSD Large High Performance Outdoor Shake Table. The 4-ft (1.2-m) diameter cantilever pier spanned 24 ft (7.2-m) above the footing. A massive 261-ton (2,322-kN) reinforced concrete block supported by the pier generated gravity and lateral inertial forces.

Stress Wave Mitigation in Porous Materials

Professor Yu Qiao

Stress wave mitigation in porous materials, such as silica monoliths and PTFE foams, are investigated. As shown in Figure 1, a hat-shaped setup on the SHPB testing system is used to induce force on the porous silica monoliths with different average pore sizes, from a few nanometers to a few hundreds of microns. Under the same shear rate and the same shear displacement, if the pore size is as large as 100 microns, the local softening caused by cell collapse will promote the formation of shear banding along the direction of shear force, and the influence area encircled by orange line will be localized. Whereas if the pore size is small enough like tens of nanometers, local hardening ahead of the shear banding will happen, leading a large influence area and thus more energy will be absorbed by the porous materials.

Fluid-Structure Interaction Modeling of Wind Turbines at Full Scale

Professor Yuri Bazilevs

(a) Methodology

(b) FSI Simulation

(c) Rotor-tower interaction

A fully coupled fluid–structure interaction (FSI) simulation methodology for wind turbines was developed in order to address a variety of engineering questions related to their aerodynamic and structural performance. Our FSI modeling takes place in 3D and at full scale, using novel finite-element-based methods for aerodynamics, and state-of-the-art isogeometric methods for blade structures. This one-of-a-kind FSI modeling methodology for wind turbines was extensively validated against experiments. The modeling ideas and simulation results are illustrated in the figures below.

Modeling the Nano-Mechanics of Single-Cell Structures

Professor Robert J. Asaro

The cell wall of S. cerevisae serves to protect the cell from thermal, oxidative and mechanical stresses and it is the target for anti-fungal drugs in pathogenic strains. It also serves as a model for cell wall formation in higher eukaryotes. Little is known about its mechanical properties due to the complex nature of its protein and polysaccharide components, and their interconnections. A multi-scale model describing the cell walls nano-mechanical response to AFM tip indentation and the whole cell's response to high hydrostatic pressure, nano-indentation and micro-manipulation compression experiments is under development.

COSMOS: Earthquakes in Action

Professor Lelli Van Den Einde

The California State Summer School for Mathematics and Science (COSMOS) is a four-week, educational summer program for gifted and talented high school students. Science and engineering topics are presented via a variety of "clusters" located at four of the University of California campuses. The "Earthquakes in Action" cluster at UCSD presents basic concepts in geophysics of earthquakes and structural design of building components and systems. It employs hands-on and interactive activities, experimental investigations, relevant site visits, and research-based group projects, all of which are integrated with lectures.

Improved Ground Vibration Testing Methods for Flight Structures

Professor John B. Kosmatka

Typical Ground Vibration Tests of flight vehicles are performed by attaching a moderate number (10 to 100) of discrete accelerometers to a free-free flight vehicle where the excitation is provided using one or more electro-mechanical shakers. A new approach involves using a noncontacting scanning laser vibrometer on the free-free flight vehicle.

The SLV has the advantage over discrete accelerometers in that a near infinite number of data points can be measured without altering the mass configuration of the flight vehicle. This large number of data points makes it easy to: (a) correlate the experimental data with analytical (finite element) results, (b) investigate local modes, and (c) investigate the affects of subtle vehicle configuration changes on the modal properties.

Announcements

  • Impacted Status for Structural Engineering Undergraduate Majors

    Please note: The majors in the Department of Structural Engineering (B.S. Structural Engineering, B.S. Engineering Sciences) have been declared "impacted", effective the following years:

    Fall 2014 - New freshman students

    Fall 2015 - New transfer students

    Fall 2015 - Continuing students

    Additional information can be found in the "Policies and Procedures" section of the Undergraduate portion of this website.

  • Faculty Recruitment

    The Department of Structural Engineering has opened a search for a tenure-track faculty member in one of the two areas: (1) GEOTECHNICAL ENGINEERING with special interest in energy-related applications, geotechnical hazards, and geo-system testing, including centrifuge and large-scale testing; and (2) STRUCTURAL HEALTH MONITORING and PROGNOSIS with special interest in the assessment of complex civil, aerospace, mechanical, and/or marine structural systems within a reliability-based approach. The recruitment will open (at https://apol-recruit.ucsd.edu/apply/JPF00481) on Monday, November 18.

    Jacobs School of Engineering (JSOE) has opened a search for a tenure-track faculty member with demonstrated excellence in teaching, scholarship, and professional activity. Applications received by December 15, 2013 will be given full consideration; however, the position is open until filled. (https://apol-recruit.ucsd.edu/apply/JPF00449)

    View Postings

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Letter from the Chair

Gilbert Hegemier
J. E. Luco
Chair

Welcome to the Department of Structural Engineering at UC San Diego. We appreciate your interest in our program. The Department website presents a detailed view of the graduate and undergraduate programs that the Department offers, together with an overview of current research areas; descriptions of our computational and experimental facilities; and profiles of our faculty and researchers. Following are some highlights of the unique characteristics of the Department:

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