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Masoud Sanayei
Professor, Department of Civil and Environmental Engineering

Research Summaries (Completed and Ongoing)

Infrastructure Systems, Services (ISS) and Climate Change: Integrated Impacts and Response Strategies for the Boston Metropolitan Area
for US ENVIRONMENTAL PROTECTION AGENCY

Executive Summary
A Joint Project of the Civil and Environmental Engineering Department of Tufts University and the Center for Energy and Environmental Studies of Boston University. Funded by the Office of Research and Development, National Center for Environmental Research and Quality Assurance of the US Environmental Protection Agency. CLIMB – Climate's Long-term Impacts on Metro Boston – is a major study of the potential impacts of climate change on infrastructure systems in metro Boston and to recommend strategies to prevent, reduce, or manage the risk. It is expected to be a ground-breaking study of national importance. The study will look at how potentially rising sea levels, higher summer peak temperatures, and more frequent and intense storms may affect our water supply and water quality, wastewater collection and treatment, drainage and flood management systems, transportation and communication, public health, recreation and tourism, our built environment, and our energy systems and demand. The project will also consider how these potential impacts relate to each other and what effects they might have on the economy, public budgets, and society as a whole.

Dr. Sanayei is a collaborator on this project.

CLIMB Project


Bridge Structural Identification for Condition Assessment
for NATIONAL SCIENCE FOUNDATION (NSF)

Executive Summary
This project focuses on exploring the role of structural identification in transforming the current semiempirical practice to a rational knowledgebase, thereby paving the way for effective and optimum infrastructure designing operation and management. Fundamental questions pertaining to the use of structural identification for bridge structures will be answered. The research will be primarily focused on structural identification in terms of data processing, quality assurance, damage evaluation, and reliability evaluation. The experimental and analytical tools that permit meaningful and practical applications of structural identification are only presently emerging. A test bridge has already been instrumented which is a 10 year old, 188 ft long, three span, two lane, integral abutment, reinforced concrete deck on steel girders overpass in the Cincinnati area to provide needed test data. Another bridge is under construction and is being instrumented with over 350 sensors. Accelerations, displacements, rotations, strains, temperatures, truckloads and environmental conditions will be monitored over the long term by intelligent monitoring systems. In addition to active and passive sensors, photogrammetric image processing technologies will be used. The structural identification experiments will include: modal testing by impact, modal testing by multi input forced excitation, geometry monitoring, traffic inputs and operating responses, environmental inputs and ambient responses, static proof level multiple truck loading, etc. A wide variety of structural identification approaches and analytical tools will be studied. 


Response-Based Parameter Estimation for Determining Unknown Bridge Foundations
SBIR Phase II Research
for FEDERAL HIGHWAY ADMINISTRATION (FHWA)
and INFRASENSE, Inc.

Executive Summary
The objective of the work described in this research is to develop a simple, low-cost method for identifying unknown bridge foundations. The proposed method, called the Response-Based Parameter Estimation Method (RPEM), is based on the determination of foundation stiffness coefficients using field measurements of bridge movements caused by live and thermal loads. According to the method, measured patterns in foundation stiffness coefficients would provide a signature for distinguishing different foundation types. In Phase I the validity of using foundation stiffness parameters to help determine foundation type was confirmed using finite element models. A parameter estimation method was developed for calculating foundation stiffnesses from field data and tested on simulated data. Field data was collected on bridges with spread footing and pile foundations subjected to a controlled truck loading and to thermal forces caused by diurnal temperature cycles. Foundation stiffness coefficients were calculated from this field data and showed distinct differences between the spread footing and the pile foundation. The differences were in the same direction and of similar order of magnitude as predicted from the finite element foundation model. Therefore, Phase I has successfully demonstrated the feasibility of the method.

Phase II research effort will focus on simplifying the instrumentation through use of parameter estimation; developing a foundation stiffness database from field evaluations on different foundation types; and packaging the system for routine applications. Based on the findings of Phase I, the overall objectives of Phase II are to: (a) simplify and improve the reliability of the instrumentation by applying the parameter estimation method to the field data; (b) further investigate the use of thermally induced movements as an additional approach for determining the foundation stiffness coefficients; (c) conduct field testing on other bridges to verify the reliability of the method under varied conditions; (d) use the additional field data in conjunction with finite element foundation models to establish a database of foundation stiffness coefficient patterns for future applications; and (e) packaging the system and develop the software for routine use by highway agencies and consulting and test engineers. Successful implementation of this Phase II program would yield a method for unknown foundation identification which will be more effective and economical than what is currently available.


Dynamic Bridge Substructure Identification and Monitoring System
for FEDERAL HIGHWAY ADMINISTRATION (FHWA)
and OLSON ENGINEERING, Inc.

Executive Summary
At Tufts University, Prof. Sanayei and a team of graduate and undergraduate students are developing a system concept for bridge substructure evaluation and monitoring. Parameter estimation will be used for bridge substructure condition assessment using nondestructive vibration test data. The Parameter Identification System (PARIS) program developed by Prof. Sanayei is capable of estimating parameters of a simple structure from measured frequencies and associated mode shapes. This program will be enhanced to handle full scale bridges and key components such as: superstructure, substructure, joints and foundations.

The main goal of this research is to identify the type of foundation beneath a bridge pier and determine its properties. Using more accurate estimates of foundation capacity, bridge load ratings may be more accurately determined. Foundation lumped stiffness and mass properties is proposed as a measure of foundation type and health. To identify this stiffness, a finite element based parameter estimation method will be used to identify the stiffness at the contact point between the bridge and the pier at the soil interface.


Wireless Evaluation of Bridge Abutments and Piers (WREBAP)
SBIR Phase I Research
for NATIONAL SCIENCE FOUNDATION (NSF)
and INFRASENSE, Inc.

Executive Summary
The objective of this project is to develop and demonstrate a low cost, easily deployed system for evaluating critical conditions in bridge abutments, piers, and foundations. Highway agencies need such a system to prevent bridge failures, most of which are caused by scour of bridge foundations producing failure of piers and abutments. The WREBAP system uses measurements of piers and abutments produced by truck and thermal loadings to determine key stiffness parameters. In phase I, finite element model analysis have been carried out, showing that foundation stiffness parameters can distinguish foundations with and without piles, and can identify foundation damage due to scour. In addition, parameter estimation studies have been conducted, showing that key foundation stiffness parameters can be determined using truck loadings and simple pier rotation measurements. Finally, field tests were carried out on two bridges to confirm the feasibility of making the required measurements. For these tests, a bridge pier was instrumented with strain gages and rotation measuring devices ("tiltmeter"), and the data was collected and transmitted using wireless data collection system. The forces and bending moments in the pier computed from the measured strains agreed with those expected from the known truck loading. The relationship between the bending moment and the measured pier rotation yielded a stiffness value which agreed closely with theory. the analytical and field results of Phase I confirm the validity of WREBAP concept, and show that the required field data can be obtained using standard instrumentation.


Response-Based Parameter Estimation for Determining Unknown Bridge Foundations
SBIR Phase I Research

for FEDERAL HIGHWAY ADMINISTRATION (FHWA)
and INFRASENSE, Inc.

Executive Summary
Evaluation of bridges for vulnerability to scour or other potential sources of damage requires knowledge of foundation conditions beneath piers and abutments that are often unknown. INFRASENSE proposes to develop and demonstrate a response-based parameter estimation method (RPEM) which will address the need for a simple, low-cost system for unknown foundation evaluation. The RPEM system is based on conventional strain and rotation measuring devices whose data are used to compute a stiffness matrix [K] for the unknown foundation, which is then matched with values previously determined for known foundations. The system will be simple in design and available for use by highway agencies and by the consulting engineering and testing community. The Phase I program addresses the feasibility of (1) making the required strain and rotation measurements on piers and abutments subjected to truck and thermal loadings: and (2) developing software which can compute the unknown foundation characteristics from this measured data. These objectives will be achieved by field testing coupled with analytic modeling and simulation.


Other Areas of Research

  • Integrated Analysis & Design of Structures
  • Performance-Based Design of Structures
  • Bridge Design and Rehabilitation
  • Vibration Testing & Data Acquisition
  • Vibration Isolation
  • Finite Elements Analysis
  • Bridge Full-Scale Testing
  • Earthquake Engineering

    Shake Table
    The Structural Engineering laboratory houses teaching and research equipment. During the summer of 1999, a shake table was purchased to support teaching and research in the area of structural dynamics, earthquake engineering, and vibration isolation. This APS Dynamics shake table and peripherals include an electro-dynamic shaker (model 400), its voltage or current amplifier (model 124-EP), a reaction mass assembly (P/N 0412) for floor vibration tests, and a table kit (P/N 0478) for horizontal or vertical excitations. For measurements during dynamic testing, five piezoelectric accelerometers (type 4384) by Bruel and Kjaer are available using five Columbia Research charge amplifiers (model 4102) to magnify their signals. For dynamic strain measurements a strain gage conditioner and amplifier system (model 2100) by Measurements Group, Inc. is used. Also, two biaxial tiltmeters (model 900 high gain) by Applied Geomechanics are used to measure changes of angle. The data from these sensors is processed and recorded by a National Instruments data acquisition system installed in a Pentium III PC. It consists of an analog breakout board with BNC connectors (model BNC 2080), a multifunction analog, digital, and timing I/O board (model Lab-PC+), and the LabVIEW 5.0 software that controls the process. Other equipment available are an oscilloscope (model LB-518) by Leader, a multimeter (model 3468A) by Hewlett Packard, a function generator (model 501A) by Tektronix, and a frequency counter (model 1900A) by Fluke. The above data acquisition system using tiltmeters and strain gages are now included in the undergraduate Structural Analysis (CEE-22) for the Influence Line experiment.