Center Identifying Number

A472

Project Title

Bridge Asset Management Based on Life Cycle Cost Considerations

Principal Investigator
Institution
Telephone Number
Email Address

Raymond J. Krizek
Northwestern University
847-491-4040
rjkrizek@northwestern.edu

Ahmad Hadavi
Northwestern University
847-467-3219
a-hadavi@northwestern.edu

Pablo L. Durango-Cohen
Northwestern University
847-491-4008
pdc@northwestern.edu

David A. Novick
Professional Consultant

Yingchun Zhang
Northwestern University (Research Analyst)

External Project Contact
Address
Telephone Number

Project Objective

The main objectives of this project are to:

• Determine the achievable useful life for a bridge
• Develop guidelines for optimizing useful life
• Determine life cycle cost of a bridge
• Formulate a cost model for bridge life cycle cost
• Determine the design practice that leads to the lowest bridge life cycle cost
• Determine MRR practices that lead to the lowest bridge life cycle

Project Abstract

Bridge asset management based on life cycle cost considerations provides a resource allocation framework for cost-effective decision-making on how to build, preserve, and improve a bridge to minimize its life cycle cost while achieving a satisfactory level of service over the useful life of the bridge. This proposed research will use actual historical cost data from a variety of geographically distributed bridges of different structural designs to formulate a cost model for bridge life cycle cost, assess the impact of deferred maintenance on bridge total life cycle cost, and develop a supporting rationale for projecting the useful life of a bridge. Guidelines will be prepared to suggest the actions that must be implemented to achieve the target useful life. The results of this study will provide critically needed supplemental input information for currently used bridge management systems, such as PONTIS, and more recent bridge life cycle cost analysis tools, such as Bridge Life Cycle Cost Analysis (BLCCA); input to these systems is currently obtained primarily from expert elicitation.

Task Descriptions

This study will be based on actual data accumulated by bridge agencies over many years. Historical data will be collected for the oldest bridges from transportation agencies or bridge owners who keep relatively good records (e. g. the City of Chicago Department of Transportation owns and operates fifty of the world oldest and largest movable bridges with relatively good life cycle records). Besides the cost data, we will collect available design details, condition data, and traffic information for each bridge to the extent practicable. Then, we will compile and organize these historical data in a form which shows the life cycle cost information in useful format. The data summary will include the bridge life cycle cost table with all costs, by year and by category for each bridge. All cost data will be adjusted for inflation by using the ENR Building Cost Index or some other index determined to be meaningful (our research plan will include a study of several indices and the merits and applicability of each).

• Formulate a cost model for Chicago Double-leaf trunnion bascules
• Conduct sensitivity analysis of the cost index
• Determine the impact of deferred MRR on total life cycle cost
• Determine the MRR practice that leads to the lowest total life cycle cost
• Determine the design practice that leads to the lowest bridge life cycle cost
• Collect detailed MRR costs for New York City bridges and tunnels
• Obtain data for appropriate bridges in California
• Conduct a comparative study between bridges and tunnels

Milestones, Dates
(inc. Project Start & End Dates)

Period October 1, 2003– September 30, 2004

For Chicago Bascules
1. Oct. - Dec., 2003: Sensitivity analysis of cost index
2. Dec., 2003 - Feb. 2004: Determine achievable useful life and total life-cycle cost
3. Jan - March: Determine relationship between initial cost and total life-cycle cost
4. Feb. - Apr.: Determine MRR cost distribution
5. Apr. - June: Formulate total life-cycle cost model
6. May - July: Determine impact of deferred MRR

For New York Bridges and Tunnels
1. Oct. 2003 - Jan., 2004: Collect and verify historical data
2. Jan. - Apr.: Analyze total life cycle cost pattern
3. Apr. - Sept.: Comparative study between bridge and tunnel based on life cycle cost

For Caltrans Bridges
1. Oct. - Nov.: Collect available historical data
2. Nov., 2003 - Feb., 2004: Analyze total life cycle cost data
3. Feb. - July: Determine impact of deferred MRR
4. June - Sept (and beyond): Comparative study among different types of bridges based on life cycle cost

Yearly and Total Budget

Total Costs- Current Year: $193,624
- Federal Share:                 $71,291              5-Year Federal Share Total: $193,624
- Matching Share:             $122,334

Student Involvement (e.g., Thesis, Assistantships, Paid Employment)

Relationship to Other Research Projects

This is the first twelve months of a proposed two year research project.

Technology Transfer Activities

Potential Benefits of the Project

One of the major requirements for effective Asset Management is having the facts to identify potential problems before they develop, and the importance of Asset Management for transportation facilities cannot be overstated. America has invested more than $1 trillion in its highway system during the past 100 years. Without proper management of this critically important asset, it will not meet future structural and functional needs. Nationwide, there are nearly 577,000 bridges, the majority of which were built during two major bridge building periods – immediately before and during the recession (1920s and 1930s) and in the first two decades of the Cold War (1950s and 1960s). Hence, a large portion of this bridge system is aging and in need of maintenance, repair, rehabilitation, or reconstruction. Asset Management provides a framework for identifying the investment needed to operate and manage these facilities systematically and cost-effectively.

The most commonly used bridge management system in the U.S., PONTIS, is basically a data information system. Bridge Life Cycle Cost Analysis (BLCCA) is a framework of life cycle cost analysis methodology. PONTIS and BLCCA rely heavily on expert elicitation and engineering judgment, such as the costs for different MRR actions, the probability of a condition changing from one status to another, the total life cycle cost, and the achievable useful life for bridge deck, superstructure, substructure, and bridge as a whole. This type of data is critical to bridge life cycle asset management. To build a new bridge or preserve and improve an existing bridge cost effectively, either within a network or for an individual bridge, it is necessary to know the economic conditions that prevail, that is: how long will it last, and how much will it cost initially and over time. If we defer MRR, how much more might it cost eventually? This research is aimed toward answering these fundamental questions, as well as supplying background data to support the implementation of existing bridge management systems and economic analyses for investment decision-making.

This research is aimed toward (a) determining the asset value or total life cycle cost, as well as the achievable useful life, of bridges and (b) suggesting design, preservation, and improvement practices that lead to lowest life cycle cost. Such results are critical to bridge asset management and form the basis for economic decision-making. The results of this study will provide critically needed information for input to currently used bridge management systems such as PONTIS and bridge life cycle cost analysis such as that advanced in the recent NCHRP study.

TRB Keywords

Bridge management systems, Life cycle analysis, Life cycle costing, Asset management, useful life, Maintenance, Repair, Rehabilitation (maintenance), Reconstruction

A473

The Materials Science of Cement

Hamlin M. Jennings
Northwestern University
847-491-4858
h-jennings@northwestern.edu

Jeffrey J. Thomas
Northwestern University
847-491-3201
jthomas@northwestern.edu

The objectives of this project are to develop an electronic document and then a web site that will provide free, up-to-date, understandable information about the materials science of concrete to anyone with access to a computer and the internet.

Concrete is the world's most widely used man-made material, and there is a huge database of empirical knowledge on how to mix, place, and cure concrete for specific applications. This knowledge has been extensively codified into standards that ensure that concrete has the required strength, durability, and other properties needed to fit a specific application. This means that the professional who works with concrete does not need to understand in detail (or even be aware of) the fundamental chemical processes that give Portland cement its useful properties. However, possessing some knowledge of the chemical processes that underlie the workability of concrete, the time to set, the ultimate strength, the tendency to shrink on drying, the tendency to deteriorate under adverse environmental conditions and other phenomena can be a great advantage. A professional with a good working knowledge of the materials science of cement can be more confident, creative, and effective in their use of concrete.

We will create an electronic document, and then a web site, that will provide free, up-to-date, understandable information about the materials science of concrete to anyone with access to a computer and the internet. The focus will always be on providing a fundamental explanation for the property or behavior, not on the empirical details which are available elsewhere. That there is a demand for such a service is, we believe, amply demonstrated by the popularity of a similar site on modeling of cement developed and hosted by National Institute of Standards and Technology (NIST). The NIST web site focuses on modeling and does not provide a materials' appreciation or materials science emphasis. Thus we believe there are both a need and an audience for a web site on the materials science of cement. Our web site will provide an obvious benefit to its users, and will increase awareness of the importance of concrete as a material.

1) Develop first an electronic document that covers the materials science of cement in detailed but understandable terms.

The following topics will be covered:

• Composition of cement powder
• The main hydration reactions (kinetics, heat release, etc.)
• The main hydration products
• Microstructure and the pore system
• The structure of C-S-H gel
• Effect of curing conditions on the properties
• Chemical admixtures and their effects
• Mineral admixtures and their effects
• Shrinkage and creep
• Chemical attack of concrete including leaching, sulfate attack, alkali-silica reaction, carbonation, etc.
• A summary of how to design, mix, and cure durable concrete

2) Produce a web site, which will have the text of the electronic document, with many additional pictures and figures. Create a commonly-asked questions section regarding concrete, with short, straightforward answers based on underlying materials science. There will be many linked cross references from one section to another to reinforce the relationships between processing, microstructure, and properties.

October 1, 2003 to September 30, 2004

Total Costs- Current Year: $67,398
Federal Share:                 $51,069              5-Year Federal Share Total: $51,069
Matching Share:               $16,328

Undergraduate students: develop web site. Potentially involve a team of students in an undergraduate engineering design and communication course that requires them to design and implement a web site for an actual client.

Concrete, Cement, Education, Materials, Websites

A474

"Safety Concrete" - A New Impact-absorbing Concrete for Protecting Buildings, Structures, and People

Hamlin M. Jennings
Northwestern University
847-491-4858
h-jennings@northwestern.edu

Jeffrey J. Thomas
Northwestern University
847-491-3201
jthomas@northwestern.edu

The goal of this project is to continue to develop and commercialize a new type of concrete that will disintegrate into small fragments (rather than fracture into large chunks) when subjected to sudden and severe loading. Because of the emphasis on preventing damage to buildings and people, this material has been dubbed "safety concrete."

The project will focus on improving the strength of the high sand mix designs formulated during the previous year, and working on manufacturing hollow blocks made of safety concrete. The hollow block configuration has the advantage of having a maximum thickness similar to that of the test cylinders we have been using to date, and thus difficulties associated with performing the drying treatment on scaled-up specimens are avoided.

Research for this year of the project will focus on the following areas:

1) Improving the strength of the high-sand mixtures while maintaining the excellent fragmentation properties.

2) Tailoring the mix designs and processing steps for the formation of hollow blocks

3) Continuing to verify the effectiveness of safety concrete through blast testing

October 1, 2003 to September 30, 2004

1. Source and order materials: Oct. 2003
2. Select, purchase and install manual block making machine: Nov. 2003
3. Design, perform, and analyze experimental matrix with high sand content: Nov. 2003 - Jan. 2004
4. Form and test concrete blocks using selected mix designs. Adjust mix designs to improve block processing and quality: Jan. - July, 2004
5. Create high-sand test panels and ship to ERDC for shock tube testing, conduct parallel tests at NWU. (may require 1-3 blast tests): Feb. - June, 2004
6. Research the cost of manufacturing, delivering, and installing safety concrete block walls: Nov. 2003 - July 2004
7. Design, perform, and analyze a focused experimental matrix to optimize the properties of safety concrete blocks: Apr. - June, 2004
8. Work with ERDC to conduct a large scale blast test of a wall made of safety concrete blocks: June - Sept., 2004
   

Total Costs- Current Year: $146,145    
- Federal Share:                 $76,145              5-Year Federal Share Total: $153,073
- Matching Share:               $70,000

Graduate student: Julie Gevrenov, MS student from the Department of Materials Science and Engineering (funded through separate fellowship)

Concrete, Barriers (Roads), Safety, Infrastructure

A475

Introducing Size Effect Into Design Practice and Codes for Concrete Infrastructure

Zdenek P. Bazant
Northwestern University
847-491-4025
z-bazant@northwestern.edu

The overall objectives of the project are:

1. Capitalizing on two decades of basic research funding of the writer's research of size effect at Northwestern University, demonstrate in journals and at conferences practical applications to design and testing.
2. Translate existing material models for quasibrittle fracture, capable of capturing the size effect, into subroutines suitable for use in computer codes in design, including commercial codes (which at present generally miss the size effect).
3. Formulate standard test procedures for concrete strength and fracture taking the size effect into account, and propose improved testing standards to ASTM, ACI and RILEM.
4. Based on the general theory already developed, construct simple design formulae for the size effect in various basic types of failure, suitable for use in design firms.
5. Work in engineering societies, particularly ACI, RILEM, ASTM and FIB (the specifications or recommendations of which are generally co-opted by AASHTO), and in the committees of ASCE which influence decisions, to introduce improvements in the respective code articles, one by one, beginning with design code specifications for shear failures of reinforced concrete structures and flexural failures of unreinforced concrete structures.
6. Formulate a statistically correct system of load factors for the code, suitable for use after the size effect is taken into account in code provisions.
7. Articulate the reasons and promulgate the necessary changes by tutorial presentations at conferences.

The objective of the project is to improve the reliability, durability and structural efficiency of infrastructure by transferring the results of previous basic research on fracture mechanics of size effects in concrete structures into: (1) design practice, (2) design codes, (3) standardized materials testing, and (4) commercial computer programs. This is important for large-span box girders of prestressed concrete bridges and cable-stayed bridges, supporting piers, column footings and foundation plinths, as well as for road and airport pavements, earth-retaining walls, dams (which often carry highways) and tunnel linings. The design practices for ductile failures are not affected, but those guarding against brittle failures, which are currently still based on the plasticity-based theory of limit states, need to be updated for size effect according to fracture mechanics and random strength statistics. Furthermore, this goal requires introduction of a standard for fracture testing, which is not yet included among ASTM standards. The commercial computer programs for simulating concrete structures are generally still not yet based on fracture mechanics and do not take the size effect into account. Although the basic theory is now ripe, however, simple design formulas for particular design problems need to be developed, proper material testing procedures instituted, and simple ways of implementation in commercial computer codes proposed and promulgated. Moreover, the relevant committees of ACI, ASTM, RILEM and FIB, the specifications of which are generally followed by AASHTO, need to be convinced.

This is the second phase a proposed three and one-half year project that will focus on the introduction of size effect, and along with it fracture mechanics background, into 1) design practice, 2) design codes, 3) standardized materials testing, and 4) commercial computer programs for concrete structures.  This is important not only for large-span pre-stressed concrete box bridge girders and box girders of cable-stayed bridges, but also for the supporting piers and foundation plinths, as well as for road and airport pavements, earth-retaining walls, tunnel linings and dams (which often carry highways). 

The design practices for ductile failures are not affected, but those guarding against brittle failures, which currently still are based on the plasticity-based theory of limit states, need to be updated for size effect according to fracture mechanics and random strength statistics. This goal requires introduction of a standard for fracture testing, which is not yet included among ASTM standards. The commercial computer for simulating concrete structures are generally still not yet based on fracture mechanics and do not take the size effect into account.

Major tasks for this twelve-month period are:

1. Based on previous research, prepare a proposal for a code specification on shear design of reinforced concrete beams without stirrups including the size effect and publish it in a design-oriented journal of ACI or ASCE.
2. As chairman of the RILEM Committee QFS, `Quasibrittle Fracture Scaling', complete the state-of-art report incorporating sound recommendations on the size effect in reinforced and plain concrete structures. Based on the theoretical researches previously carried out at Northwestern, submit the report for balloting by the Committee and, if approved, submit it to Materials and Structures for publication.
3. As member of ACI Committee 445, Shear and Torsion, move forward the adoption of a realistic size effect code formula for shear failure of reinforced concrete beams without stirrups, and code formulas for shear failure of beams with stirrups and for torsional failure.
4. As a new member of the strength subcommittee of ASTM Committee C-09 (Concrete), prepare in a specified web format a detailed formulation of a revision of ASTM standard on the modulus of rupture (i.e., flexural strength) incorporating the size effect, and submit it for committee approval.
5. As member (and former founding chairman) of ACI Committee 446, Fracture of Concrete, articulate in ACI and ASTM the pros and cons of various fracture test methods, and submit it for committee approval.
6. Prepare a study of the effect of boundary layer at the far side of the ligament with the objective of compensating for the deleterious effect in the standard fracture test.
7. Prepare a paper and present it at the 5th International Conference on Fracture of Concrete (FRAMCOS-5, Vail, Colorado, April 2004) dealing with the fracture energy testing.
8. As member of the Scientific Committee, collaborate on the program themes for the 2nd International Conferences on Bridge Management and Maintenance, IABMAS, Kobe, Japan 2004, and possibly prepare a joint paper with visiting scholar D. Novak on reliability aspects of prescribed load combinations and safety factor, with particular attention to the self-weight effect.
9. Clarify in papers and conference presentations the requirements for confining reinforcement of concrete columns (tied, spiral and tubular, including bridge columns) needed to suppress or minimize the strain-softening response of concrete and thus to suppress or minimize the size effect.
10. Collaborating with my former assistant, Prof. Y. Xi, bring to completion the preparation of a special issue of ASCE Journal collecting the papers from the NSF International Workshop on Durability Problems of Structures (including bridges), which I organized and chaired.
11. Analyze the problem of reliability of design of quasibrittle structures of different sizes, write a journal article on this subject and present the results in design conferences and in seminars with design and construction oriented audience.
12. As member of ACI Committee 447, Finite Element Analysis of Concrete Structures, promulgate a revision of standard finite element codes making it possible to capture the size effect (which means nonlocal modeling or incorporation of energetic concepts of fracture mechanics) and prepare a paper on this subject for the up-coming US-Japan Workshop.

October 1, 2003 to September 30, 2004

Tasks 1 & 2.   Q4 2003
Task 3.   Q4 2003 - Q1 2004
Task 4.   Q4 2003 - Q3 2004
Task 5.   Q1 & Q2 2004
Task 6.   Q1, Q2 & Q3 2004
Task 7.   Q1 2004
Task 8.   Q3 2004
Task 9.   Q1 2004
Task 10. Q1 & Q2 2004
Task 11. Q3 & Q3 2004
Task 12. Q1 & Q3 2004

Total Costs- Current Year: $179,570
- Federal Share:                 $89,282              5-Year Federal Share Total: $216,436
- Matching Share:               $90,288

Graduate Research Assistant: 1) Qiang Yu and 2) Sze-Dai Pang. Both are graduate research assistants, working on their doctorates.

Fulbright Fellow working on the project, fully supported by the Fulbright Foundation: Milan Vorechovskky, a doctoral student Tech. University Brno, Czech Republic

This is a continuation, following the first eighteen months, of a proposed three and one-half year project.

Much of the focus of this project is on technology transfer through advancing updates to codes, advancement of new design and testing methods, and presentations at conferences.  The PI will be active in the relevant committees of ASTM, ACI and RILEM. Activities include promoting new and updated codes, design recommendations and testing methods as part of the ASTM Committee C-04 (Concrete) and subcommittee on strength testing; ACI Committee 447 (Shear and Torsion); ACI Committee 446 (Fracture of Concrete); RILEM Committee QFS (Quasibrittle Fracture Scaling). Additional transfer activities include writing journal articles and presenting papers at international conferences, such as at the 5th International Conference on Fracture of Concrete (FRAMCOS-5, Vail, Colorado, April 2004) dealing with the fracture energy testing, and collaborating on the program themes for the 2nd International Conferences on Bridge Management and Maintenance, IABMAS, Kobe, Japan 2004

According to the classical theories of failure such as elasticity with a strength limit of plastic limit analysis, a structure fails when the maximum stress reaches a certain critical value that is independent of structure size.  This simple concept is valid for many situations, for example the bending failure of a steel girder or the failure of tensile reinforcement in a reinforced concrete beam.  In modern concrete structures, however, there are many situations where this simple concept breaks down and the apparent material strength (or nominal strength) decreases with increasing structure size.  This is called the size effect.

There are two physical causes of size effect: 1) the statistical cause, consisting in the randomness of material strength; and 2) the deterministic cause, consisting in the release of strain energy stored in the structure into the front of a propagating crack. 

The basic theory of the statistical size effect, formulated by Weibull in 1939, was universally believed to be the only explanation of the size effects observed experimentally in concrete structures until the 1980s.  The belief is no longer universal.  A theory is now generally accepted by the leading researchers that deterministic size effect exists and is in fact dominant for all quasibrittle materials, not only concrete, but also rocks, ice, tough ceramics and fiber composites.  However, the theory has not yet penetrated general concrete practice, design codes, materials testing, or the commercial computer programs for structural design. 

The basic theory of the deterministic size effect was developed largely at Northwestern by the PI, under a series of grants from NSF, AFOSR and ONR.  It was presented in a recent textbook (Bazant and J. Planas, Fracture and Size Effect, CRC Press, Boca Raton 1998), and the advanced aspects in a monograph just published (Bazant, Size Effect on Structural Strength, Hermes-Penton, London 2002).  The present project is aimed at bringing this new theory into practice.

Concrete, Infrastructure, Fracture mechanics, Design standards

Improved Condition Monitoring for Bridge Management

David Prine
Infrastructure Technology Institute
847-491-2873
dprine@northwestern.edu

The objective of this program is to provide bridge owners with a set of advanced NDE tools so that they may better (more quantitatively and with improved repeatability) determine bridge condition, which is the primary input to a bridge management system.  These tools will consist of both equipment and procedures to aid in the inspection of critical bridge components.

The user group development effort maintains a strong involvement with the user community through meetings. Newsletters, and electronic communications via the Internet have also been very effective. Many of our new customers and potential deployment partners contact us because of our Internet presence. We are closely coordinating our user group efforts with the Mid-West Bridge Maintenance and Inspection (BMI) working group.

The field tests and demonstrations allow for development and refinement of the bridge monitoring technology. It also helps to forge working relationships with practitioners and provides a vehicle for strengthening the integration of the ITI staff/NU faculty team members by providing opportunity for field verification of newly emerging technology. The increased student involvement in this activity exploits the educational opportunities offered by providing hands-on experience by students under real field conditions and is becoming a major growth area. Both of these tasks (Users Group and Field Tests) also are the main marketing vehicles for additional commercialization efforts in the service area.

The emphasis for this funding period will be on expansion of the autonomous web-based active remote monitoring technology. This will be accomplished primarily through demonstrations to infrastructure owners. Additionally, a considerable amount of acoustic emission testing is anticipated.

Task 1. Field Tests and Demonstrations

This task is a continuation and expansion of the ongoing efforts in this area. A major portion of the effort will be focused on the continuation of the demonstration and evaluation of the remote monitoring technology that emerged in previous years' work. The automated internet-based approach will be demonstrated to both state and municipal DoT's. A new internet based remote monitoring demonstration test site has been requested by the Kentucky Transportation Cabinet and researchers at the University if Kentucky. This year ITI will install an over height truck impact monitoring system on an interstate overpass bridge just south of Frankfort, Kentucky. The system will also feature video, strain, vehicle height, and weather sensors. All data will be accessible in real time over the internet. Users will be able to set their own individual notification method and criteria when events occur. We had a revival of our acoustic emissions (AE) applications this year with the Miller Park tests. We anticipate more work of this type with Hardesty and Hanover, the consulting firm that we worked with on the Miller Park Tests. The Bryte Bend retrofit project, which was again delayed during 2002/2003, has finally been contracted out. We will assist Caltrans in their evaluation and monitoring of this retrofit. Our efforts in this program will consist of applying and further refining the AE technique we developed during the earlier retrofit design and evaluation. We will evaluate approximately 12 to 15 cross-frame connection sites prior to and immediately following retrofit to assess the effectiveness of the retrofit in alleviating fatigue crack growth. This project will also allow us to gain experience with recently acquired waveform pattern recognition software which was not available during the original work on this structure. The AE monitoring will be done in two one-week trips to Sacramento. This project will not produce revenue because of out of state funding difficulties with Caltrans but it will generate considerable in-kind cost match. The steel portion of the retrofit is over 7 million dollars. We have completed the current Master Contract with WisDOT and in anticipation of more emergency task orders will prepare of a new 2 year master agreement and submit it for approval.

Task 2. User Group Development

The user group development work that was started in Year 1 and continues through the subsequent years is a vital part of this program. It continues to provide guidance to the Northwestern University (NU) researchers and is a valuable source of information exchange between bridge engineers from the various states as well a method of keeping bridge engineers informed of the developments of our NU researchers. The restrictions to interstate travel that were imposed on State and Municipal DoT personnel have continued and actually worsened. This fact of life has caused us to increasingly emphasize forms of communications other than the traditional topical meeting. We will continue the application of the H.323 teleconferencing technology to special topical meetings between NU researchers and various selected deployment partners, particularly where 2 way communications are needed. Additionally, we plan to continue to both stream and archive selected presentations and make them available for free by mail (CDROM) for practitioners that do not have fast Internet connections available. We will also continue to support the BMIWG meetings with this technology where appropriate. We will organize 4 trips to various state and municipal DoT's to demonstrate the automated internet based remote monitoring capability. Participation in various committees and working groups that are organized by other infrastructure and NDE groups will continue.

Task 3. Educational Activities

October 1, 2003 to September 30, 2004

Total Costs- Current Year: $766,842
- Federal Share:               $383,212              5-Year Federal Share Total: $1,415,496
- Matching Share:             $313,838

We will continue to organize and support educational tours to various infrastructure-related locations (fabrication facilities, historical bridges, construction sites, etc.).  Students and faculty are invited to participate in our field test efforts on a regular basis. 

We also expect to continue to provide support for graduate students who are involved with research activities under the direction of our faculty partners.

During last year's effort the emphasis was on development of active monitoring technology for our remote monitoring sites, student / faculty support, large bridge instrumentation and testing, and user group activities. These activities will continue during the coming year.  Our current student / faculty activities continue to represent a major portion of total staff time.  Growth of the remote monitoring technology that was started during Year 3 with the Michigan Street Bridge in Sturgeon Bay, Wisconsin continued.  This year's efforts have further solidified ITI's leadership position in this area.

We also expect to continue to provide support for graduate students who are involved with research activities under the direction of our faculty partners.

This year another marketable product has emerged from the work done under this program. The automated internet-based remote monitoring technology was developed by two undergraduate students who worked part time for ITI, David Kosnik and Mat Kotowsky. They recently graduated from Northwestern University and the University of Illinois - Urbana/Champaign, respectively and are in the process of starting a business (Civil Data Systems) that will provide this technology as a service to the DoT's interested in remote continuous monitoring. This development provides an excellent solution to the data overload problem that results from continuous monitoring. ITI is assisting in the incubation of this business and the recent graduates are now half-time employees of ITI.

A major contribution to improved condition monitoring of critical infrastructure has been made through the development of remote monitoring technology under this program.  The first application occurred in 1995 in Sturgeon Bay, WI.  Since then great strides have been made in system complexity and improved reliability.  The numbers of long term sites and applications have continued to expand primarily because this technology addresses a need that is readily recognized by the infrastructure owners.  Safe economically practical life extension of critical portions of the infrastructure demands improved condition monitoring and the remote technology provides a solution to this growing need particularly when one considers the added problem of downsizing imposed on the owners and operators by budget shrinkage.  The ability to interrogate a remote site without actually sending an inspector out to the site is an obvious improvement over present methods.

Bridge management systems, Infrastructure, Monitoring

A477

Nondestructive Determination of Early-Age Concrete Properties with an Ultrasonic Wave Reflection Method

Surendra P. Shah
Center for Advanced Cement-Based Material
Northwestern University
847-491-7878
s-shah@northwestern.edu

The general objective of this research is to take advantage of the results of the previous funding periods to fine-tune the wave reflection method and enhance its ability to accurately monitor the evolution of early-age concrete properties. A central point of these efforts will be to eliminate the need for calibration tests. At the present state of the research, calibration is needed to determine the actual compressive strength of concrete from the in-situ measured reflection loss. The results of the previous research have revealed several possibilities to achieve this goal. Although each phase has its own specific outcome allowing conclusions that are independently valid, these results have to be considered as intermediate. The maximum benefit of the previous work can only be unfolded if these results are evaluated in connection with each other. This comprehensive analysis is the subject of this research.

The nondestructive, in-situ testing of early-age concrete properties is a crucial tool for monitoring the progress of many construction projects in the building sector. The application of such techniques can establish the earliest possible form removal from concrete construction elements, thereby opening highways to traffic, releasing prestress from steel reinforcement, or applying post-tensioning with greatest efficiency.

A nondestructive, ultrasonic technique, which measures the reflection loss of ultrasonic shear wave reflections from the concrete surface, was developed at the Center for Advanced Cement-Based Materials (ACBM). The focus of this research project is to develop a nondestructive field sensor for in-situ monitoring of the setting, hardening, and strength gain of cementitious materials.

The research here will immediately tie in with the results of the previous funding period. Special attention will be given to determining the need of the test method to be calibrated for different mix designs. It is our aim to merge the results of experimental studies and numerical modeling to create a model for predicting early-age concrete properties from in-situ wave reflection measurements.

The research will focus on the following:

I. Constitutive Model
- model for evolution of early age properties on basis of wave reflection measurements
- linking results of fundamental parameter study with numerical modeling
- eliminating need for calibration

II. Practical Application
- develop procedure to combine wave reflection method and temperature measurements
- full scale test on massive concrete structure
- further field tests

Part I. Development of Constitutive Material Model

The first part of the research is aimed at developing a constitutive model for the evolution of early-age concrete properties on the basis of the wave reflection measurements by interrelating the results of the studies on fundamental material parameters and the numerical modeling. For this constitutive model, the input parameters will be concrete mix design (w/c-ratio, cement type, additives), and the reflection loss measured in-situ on the structure. We will evaluate the potential of this type of model to predict the elastic modulus or compressive strength of early-age concrete without further calibration.

The aim of this part of the research is to develop a constitutive material model that can determine early age concrete properties based on the mix design of the concrete and the reflection loss measured in-situ at the structure. The final goal is to develop the model in a form that requires no further experimental calibration. The basis of the model will be the results of the study on the fundamental relationships between reflection loss and basic concrete properties and the results of the numerical simulation.

The model will be based on relationships originating from two different concepts. One important component will be the results obtained from experimental studies. The previous experiments investigating the relationship between the reflection loss and fundamental material parameters have shown that the reflection loss has a unique relationship to the gel-space ratio of the cement paste. This relationship was not found to depend on the w/c-ratio.

The second component is a set of fundamental relationships obtained from the numerical simulation of cement hydration and their relationship to the reflection loss. The simulations have shown that the reflection loss and the contact area of cement particles have a unique relationship independent from the w/c ratio. It was also found that compressive strength and contact area have the same unique relationship.

These two basic relationships will be incorporated into a model that will have the ability to predict early-age concrete properties, e.g. compressive strength. This part of the research will also determine if the identified relationships among reflection loss, gel-space ratio, and contact area are universal enough to be used for different cement types, curing conditions, admixtures, and aggregate types. Most likely, the model will have to be applied in combination with a database that provides the necessary information related to the individual applications.

Part II. Practical Application of Wave Reflection Method

In the second part of the research, the practical application of the wave reflection method will be given special emphasis. A concept will be developed that provides a procedure for relating reflection loss measurements taken at the near surface of a structure to the properties of other more critical locations. The key to this procedure will be temperature measurements on the structure in conjunction with a suitable maturity function. A large-scale experiment will be conducted to verify this concept. This experiment will be performed outdoors.

To more accurately investigate this phenomenon, experiments will be conducted to determine the influence of fine aggregates on the reflection loss behavior. The mortars tested previously contained mono-sized silica sand with a very small aggregate size. Additional experiments will be conducted with mortars containing different types of sand (larger aggregate sizes, lightweight sand, etc.), and the appropriate cement paste. The results of this part of the research is of particular importance for further development of the test method, since the influence of different sand types used in field concrete mixtures must be understood.

To facilitate the transition of the wave reflection method to field application, it is necessary to have reliable information about the ability of the test method to predict the bulk properties of a concrete structure from measurements conducted near the surface. In order to obtain this information, a large-scale laboratory test will be conducted. The concrete structure to be tested will consist of a massive and a slender section. The massive section will resemble concrete curing conditions of a massive structure with high heat of hydration, while the slender section will simulate concrete curing conditions of a slab with lower heat development (such as used for highway pavements or floors).

Part III. Field Testing

Within the frame of this research, field testing is considered as a continuation of the Parts I and II. The existing collaboration with Rocky Mountain Prestress, Denver, Colorado will be continued. A main focus of the field testing will be to solve questions regarding the need of the test method to be calibrated for certain concrete mixture compositions. The constitutive model to be developed in Part I of the research will be applied for the field measurements. Usually precast plants are using a range of concrete mixes for their applications and it will be the goal to determine if the test method can predict properties of this range of mixes without calibration. Because it might be necessary to calibrate the method for a certain range of concrete mixes, calibration experiments for certain mixes will be conducted in the ACBM lab before the actual field tests.

Another direction is to focus on highway paving mixes, which vary less than construction mixes do. ACBM will work within the Midwest Concrete Consortium to determine the number of different mixes used by various state DOT's in their paving and bridge construction. We will also continue to promote the wave reflection technology to these potential customers.

A third possibility is cast-in-place concrete construction, where depending on the application a broad range of concrete mixes are used. However, there is a trend on large projects, to establish a local batching plant to more closely control mix design. It seems logical, given the stage of wave reflection technology development, to establish a collaboration with a construction firm that undertakes such major projects, in order to limit the range of mix designs across which a calibration matrix must be developed.

The on-site field testing will yield information about the degree of calibration that is needed to monitor concrete properties with the wave reflection method, being used in conjunction with the developed material model.

October 1, 2003 to September 30, 2004

I. Constitutive Modeling
- 3rd Q. 2003: build up of model
- 1st Q. 2004: validation of model
- 2nd Q. 2004 on: applicability of model for different types of materials

II. Practical Application of Wave Reflection Method
- 2nd Q. 2004: influence of aggregates
- 3rd Q. 2004: large scale experiment (lab)

III. Field Testing
- after completion of first two phases, possibly end of funding period

Total Costs- Current Year: $228,332    
- Federal Share:               $114,166              5-Year Federal Share Total: $225,458       
- Matching Share:             $114,166

Post-doctoral fellow: Thomas Voigt

This project builds on a prior research project, "Nondestructive Testing of Early-Age Concrete Properties with an Ultrasonic Wave Reflection Method".

The wave reflection technology has reached the stage of development where market feasibility and instrument manufacturer must be considered. Earlier in this project, ACBM made preliminary visits to two manufacturers of concrete analytical instrumentation: Germann Instruments and James Instruments. Both have shown initial interest in the wave reflection concept and have urged ACBM to maintain contact with them to chronicle our progress. During this project period, we will again meet with representatives of both companies to update them on the progress we have made. We will also establish a collaboration aimed at 1) assessing the market potential for a WRF instrument, and 2) developing a robust, field-friendly package for beta-site testing.

We will establish stronger ties to representative companies in the three concrete construction areas: precast, paving, and cast-in-place construction. Efforts during last year's project resulted in a strong tie-in to a precast manufacturer (arranged through the major U.S. cement producer and an ACBM member) and a field trial at the precast plant. During this project period, we will strengthen that precast relationship by arranging a subsequent field trial that will include the array of mix designs used by the precaster and the development of a calibration matrix for those mixes.

ACBM has also begun to build a working relationship with the highway paving industry. This began with our membership in the Midwest Concrete Consortium (MCC); a group of state DOT's that comes together twice yearly to discuss paving issues and to fund the development of new technology.

ACBM has also established an affiliation with the Portland Cement Concrete Pavement Technology Center (PCC) at Iowa State University. This Center works closely with the FHWA and receives earmarked funding aimed at the development of highway paving technology. ACBM and PCC currently have a joint proposal before the FHWA to explore self-consolidating concrete (SCC) technology for highway paving.

ACBM also is aligned with the FHWA and is involved in hosting a workshop this fall for their Task 15, the development of a research roadmap for highway paving technology. We are working through the MCC and the FHWA's Task 15 to introduce the wave reflection technology to the state DOTs. One presentation at MCC was accomplished last project period. Our goal will be to gain permission for a field trial at a paving site.

Finally, we will work to establish a stronger connection to the cast-in-place construction industry. The initial contacts will be made through Wiss, Janney, Elstner Associates, a well-known concrete consulting firm and an ACBM member. Through their contacts and introductions, we should be able to choose a suitable company with which to begin talks about a field trial.

The results of the research will be published in appropriate journals to ensure the national and international outreach of the test method. The research work will also be presented at conferences dealing with testing and evaluation in civil engineering. Besides the presentation on national conferences or seminars organized by the Center for ACBM it is planned to attend one international conference to introduce the results to the international research community.

Results of the research conducted in the previous funding period were presented at the ACI Spring Convention 2003 in Vancouver, Canada. The presentation was held within the Session "Hydration Kinetics, Maturity and Early-Age Properties of Concrete" organized by the ACI Committee 231 "Properties of Concrete at Early Ages".

A technical paper about the research previously conducted was presented at the Sixth International Symposium on Non-Destructive Testing in Civil Engineering , in September 2003 in Berlin, Germany. An additional technical paper was submitted for publication to the ACI Materials Journal.

The ACBM newsletter "Cementing the Future", which is distributed to over 4000 people in academic and industry worldwide, has published an overview article about the wave reflection method in its Winter 2002-2003 edition .

The wave reflection method will also be highlighted in the October 2003 ACBM Update , in the American Concrete Institute publication, Concrete International.

The nondestructive, in-situ testing of early-age concrete properties is a crucial tool for the progress of many construction projects in the building sector.  The application of such techniques can establish the earliest possible form removal from concrete construction elements, thereby opening highways to traffic, releasing prestress from steel reinforcement, or applying post-tensioning with greatest efficiency.

Concrete tests, Nondestructive tests, Ultrasonic tests, Infrastructure, Construction

A478

Automated Deformation Monitoring

Richard J. Finno
Northwestern University
847-491-5885
r-finno@northwestern.edu

Advisory Board consisting of a number of professionals, representing contractors, engineers and owner representatives, including:

• Dr. Jerry Parola, Case Foundation
• Mr. William Hansmire, Parsons Brinckerhoff, New York
• Mr. Dimitrious Koutsoftas, Jacobs Associates, San Francisco
• Dr. Paul Sabatini, GeoSyntec Consultants
• Mr. Zenon Stuck, Department of Transportation of the City of Chicago
• Mr. Michael Wysockey, Thatcher Engineering (the support system subcontractor for the Ford Engineering Design Center)
• Dr. Bryan Sweeney, Haley & Aldrich, Boston

To improve the state-of-the-art and practice of predicting and controlling ground movements associated with supported excavations and tunneling operations, and the consequent deformations of adjacent structures and utilities, this project will automate the data collection, data transmission and interpretation of deformations associated with construction operations. In particular, optical survey measurements will be remotely obtained, transmitted to a remote location for processing, and processed automatically so that the results can be interpreted in a timely fashion and be input to a numerical procedure that is used to compute ground movements.

These improvements will be checked, and ultimately verified, in the field in real time during the excavation for the Ford Motor Company Engineering Design Center on the campus of Northwestern University. These techniques will have application to any project where deformations must be measured to verify performance or control construction operations.

Many transportation projects require detailed performance monitoring as they are constructed. When optical survey points are used, this operation becomes labor intensive and time consuming, and the transmission of the data to interested parties is slow. Consequently, the information cannot be used during construction in a timely fashion.

One example where such data are routinely used is when making deep excavations or when tunneling in urban environments. A major concern in these projects is the impact of construction-related ground movements on adjacent buildings and utilities. The ground movements cause any structures within the affected zone to deform and possibly sustain damage. It is critically important to predict and control the magnitude and distribution of the ground movements that result from creating the underground space.

However, it is quite difficult, if not impossible, to use the observed movements for these purposes in a typical project where time is of the essence to a contractor. To obtain optical survey data, process it, and use it to "calibrate" the results of a finite element model is a time-consuming, and here-to-fore a trial-and-error, process. This updating process presently can be done with the commitment of a significant number of personnel, but cannot be accomplished in a time frame that provides useful feedback to a contractor during the normal pace of excavation activities.

This project will develop a system that allows one to use a total station to automatically sense the lateral and vertical movements of optical survey points, to transmit the data to a remote location where it can be automatically processed, and to present the data in such a way that meaningful interpretations can be easily made. This capability will remove some of the impediments that prevent the use of intelligent updating of performance data to control construction operations.

Develop software needed to acquire and process the measured data:

We have already purchased a Leica TPS1100 Professional series total station. The instrument includes monitoring firmware and robotic capabilities (ATR) that allow for repeated automated measurements of as many as 100 predetermined survey points. We will develop software needed to acquire and process the measured data and test the system under field operating conditions at the excavation for the Ford Engineering Design Center.

Software must be developed to obtain a reading of an optical survey point, to transmit and store the data in a remote host computer program and to develop a graphical representation of the data so that an interpretation of the results can be quickly made.

After the coordinates of each optical survey point has been found with the total station, the total station can be programmed internally to remember the location of each point. We can then develop a remote host program which will initiate the reading cycle, instruct the total station to find each point and obtain its coordinates, and send the coordinates back to the host program. This data can be processed by evaluating relative movements between a survey point and several reference points established outside the zone of influence of the excavation to determine the lateral and vertical movements of the optical survey point. We will do this for transmission over a phone line, which in many urban construction sites is the best way to accomplish this task, and for wireless data transmission, which is better for remotely located sites, such as highway or railroad bridges.

We will use a geographical information system to store the data and to present it in a graphical form. This data conversion and plot creation will allow for the displacement data to be used in several applications and analyses and to be accessible to multiple users. Within the program at the host computer, we must also interpret the data by comparing results of each optical survey point with data obtain at stationary reference points. These reference points can be located on the lower portion of a building outside the zone of influence of the excavation and/or in a deep benchmark that is set on top of rock or within the hard soil 70 ft or more below grade at the Ford Center.

Test System in Field

Once the system has been tested in the laboratory to check the coding, we will install the total station atop the roof of the southwest wing of the Technological Institute which is adjacent to the excavation for the Ford Motor Company Engineering Design Center. We will compare the results collected by the total station with (1) data collected by the conventional optical survey points established around the excavation, (2) the lateral movements measured at the tops of the inclinometers, and (3) the settlements measured by the horizontal inclinometer. This will allow us to evaluate the accuracy of the data within the context of conventional measurements at a construction site.

The scheduled duration of this work is from October 1, 2003 through September 30, 2004. Construction for the Ford Motor Company Engineering Design Center is scheduled to begin in mid-October with the excavation and backfilling operations to last approximately 9 months. We plan to have the coding for the total station done within the first month of the project so that the total station can be deployed very close to the start of significant construction activities.

Data will be collected throughout the excavation and backfilling period, and adjustments to the coding will be made as necessary. We will work initially to establish the phone link as the interface between the total station and the host computer, and we expect that that will be accomplished before start of construction. We estimate that it will take about 3 months to establish a wireless link. It will be important to maintain the system through the winter months to evaluate its robustness and develop, if necessary, means to "harden" the device to the elements.

Total Costs- Current Year: $1,222,984
- Federal Share:                    $84,363              5-Year Federal Share Total: $84,363
- Matching Share:             $1,138,620

Graduate student:
- Tanner Blackburn, PhD student

We propose to present our results to an advisory board consisting of practicing engineers, contractors and owner's representatives to provide review for the results of the research and to assure that the results are relevant to engineering practice. This board has been formed as part of the PI's National Science Foundation grant entitled "Objective updating of design predictions for supported excavations using construction monitoring data." This board meets annually, and the results of this work will be presented to them as part of the annual meeting scheduled in October of each year.

The principal investigator will present the results of the study to professional societies both locally and nationally. Papers will be submitted to journals and future conferences to further disseminate the findings.

The automated data acquisition and processing is but one portion of the system that needs to be developed to achieve real time construction feedback and control. Current work funded by the National Science Foundation includes developing inverse analysis techniques that allows one to automatically update parameters in a numerical model in a rational manner, the lynchpin analytical technique on which the system relies. This leveraging of resources from sources that fund fundamental research (NSF) and applied research (ITI) is a relatively unique opportunity. Furthermore, the work will be conducted at the excavation for the Ford Motor Company Engineering Design Center, located immediately to the south of the Technological Institute on the Evanston campus of Northwestern. This represents an unprecedented opportunity since the excavation will be located immediately adjacent to the building where proposed research will take place. Easy access to the total station will allow us to make adjustments as we proceed, to verify that the data represents actual conditions, and to assure that conventional data is available against which the automated system can be checked.

The excavation for the Ford Motor Company Engineering Design Center will be approximately 150 ft by 150 ft in plan and 35 ft deep. The soil will be supported by a sheet-pile wall braced by three levels of cross-lot members. The movements that develop as the excavation is made will extend underneath the adjacent Technological Institute. Because "Tech" is supported by shallow foundations, the building will move with the soil. A value of 1.5 inches of either vertical or lateral soil or structural movement has been set as the limit of allowable deformations for the project. Consequently, there will be inclinometers placed around the excavation and conventional optical survey points established on the ground and Tech to measure the ground response to excavation. These points will be read at least weekly during excavation. The critical nature of the displacements will ensure that close attention will be paid to the movement data as it is collected, and thus assures a good data set against which the total station data can be compared.

Deformation, Monitoring, Inclometers, Excavation, Construction, Automatic data collection systems, Infrastructure

A479

Nondestructive Evaluation of Concrete with Guided Waves

Richard J. Finno
Northwestern University
847-491-5885
r-finno@northwestern.edu

The objectives of this work are to extend the guided wave theory to flexural wave propagation in concrete columns and piles and both longitudinal and flexural waves in embedded plates (representing cast-in-place and soil mixed walls).

The purpose of this project is to develop methods to non-destructively evaluate the condition of concrete components of bridges, including columns, foundation elements and bridge piers by extending guided wave theory to flexural wave propagation in concrete columns and piles and to longitudinal and flexural waves in embedded plates (representing cast-in-place and soil mixed walls). A theory based on guided waves, describing the relation between frequency and group velocity of frequency-controlled excitations, has been developed for longitudinal wave propagation in cylindrical members to allow higher frequencies to be used to non-destructively evaluate such members, and, consequently, to identify smaller defects than possible with conventional techniques.

Many times one cannot access the top of a cylindrical element, but can only place instruments on the sides of the member, for example, at a pier for a bent of a bridge. When energy is added at the side of a column, one can generate flexural waves that have different propagation characteristics than longitudinal waves. Flexural waves in general are dispersive, i.e., their propagation velocity depends on frequency. Furthermore, the displacements associated with flexural waves also depend on frequency. Hence to use these waves to non-destructively evaluate a member, one must have the dispersion relation in hand to know how fast the waves travel and to locate the optimal position of a transducer to measure the response. Whereas the theoretical solution for flexural wave propagation in a concrete cylinder has been published, to use the information, one must numerically evaluate the solution to find propagation velocities and displacements. The solutions for embedded cylinders that represent concrete piles, has not been published for flexural wave propagation. The numerical solutions for both longitudinal and flexural wave propagation for embedded plates do not exist.

The work for this year will focus on two main areas, (1) theoretical development of the guided wave approach to consider flexural wave propagation and to consider guided waves in embedded plates, and (2) continued development of the prototype system to induce and measure guided waves.

1. Develop the theory of the guided wave approach to consider flexural wave propagation and to consider guided waves in embedded plates

We will extend the guided wave theory to look at flexural wave propagation in concrete cylinders and piles. We also will extend the guided wave theory to embedded plates so that we can develop techniques applicable to in situ walls, such as structural slurry walls or soil-mixed walls, that comprise part of many excavation support systems. The question of integrity of these wall systems arose a number of times during construction of the Central Artery / Tunnel project in Boston and during construction of the secant pile wall at the Chicago-State Subway Renovation project. During our work on these projects, we found that the conventional techniques based on 1-dimensional wave propagation in a cylindrical structural element were inadequate to provide answers regarding integrity of the as-built walls. We will develop solutions for longitudinal and flexural wave propagation in embedded plates.

The theoretical evaluations will include derivation and solution of the governing equations, parameter analysis, and interpretation of the results of flexural wave identification tests, a conventional non-destructive technique that use relative low frequency (assumed non-dispersive) flexural waves to evaluate integrity of concrete piles and shafts.

2. Develop the prototype system to induce flexural guided waves

With a theoretical solution in hand to the guided wave problem for flexural wave propagation along a cylindrical pile and a prototype experimental system for inducing high frequencies bursts of energy available, to successfully apply the guided wave approach for evaluation of concrete cylinders and piles, the following tasks must be performed:

1. Conduct laboratory verification tests of the system: In tests wherein flexural waves are to be induced, a single shaker will be mounted in the center of a plate or cylinder with incident angles of 45° and 90° for a plate and cylinder, respectively. In these cases, multi-axial accelerometers will be mounted on the top surface of the concrete to measure the response and verify the mode of the received signals.
   
2. Trial and optimization of the developed technique for the prototype piles installed at the National Geotechnical Experimentation Site (NGES) at Northwestern University: Five prototype concrete piles have already been installed at the site and will be evaluated with flexural guided waves.

The work for this project will take place from October 1, 2003 to September 30, 2004.  All tasks will occur simultaneously. Field work at the Northwestern NGES will take place whenever the weather permits.

Total Costs- Current Year: $1,453,819
- Federal Share:                  $162,018              5-Year Federal Share Total: $494,477
- Matching Share:             $1,291,802

Graduate students:
- James Lynch, working on PhD
- Helsin Wang, working on PhD

Continuation of earlier project "Improved Condition Monitoring of Bridges: Nondestructive Evaluation of Foundations"

In 1996, 1997 and 1999, the P.I. taught "Foundation Evaluation with NDE Techniques," part of a wider course entitled "Nondestructive Evaluation of Bridge Conditions," for the University of Wisconsin-Madison Department of Engineering Professional Development. He expects to teach the class again as the opportunity arises. The PI will continue to participate in the User's Group meetings for the Bridge Project.

Longitudinal and flexural stress waves in concrete are dispersive in nature, that is their propagation velocity and displacements depend on frequency. This feature is not taken advantage of in conventional NDE tests, such as impulse response, that rely solely on identifying reflections of low frequency, one-dimensional compression waves. Drilled shafts that are relatively long or embedded in dense soil lose a significant amount of stress wave energy, owing to leakage into the surrounding medium, and cannot be reliably tested with these techniques beyond a certain limit, which we have defined in the past several years of this project. The use of frequency-controlled, guided stress waves offers an approach that may overcome this limitation. Guided stress waves have been successfully used for non-destructive flaw detection and characterization of structures, such as bounded metal hollow cylindrical tubing. We are the first research group to take advantage of guided waves when non-destructively testing concrete piles and shafts.

Whereas the longitudinal wave propagation solutions are useful, we can further extend the method to cover other conditions commonly encountered in the field. When the top of a concrete column or pile is inaccessible, one can attach transducers to its side, induce a flexural wave, and observe the response. Alternately, quality control of a cast-in-place concrete wall cannot be accomplished with conventional techniques. Thus we seek to extend the method to consider embedded plate-like structures.

Bridge, Infrastructure, Monitoring, Nondestructive testing, Concrete, Longitudinal waves, Flexure, Foundations

A480

Autonomous Crack Monitoring Continuation

Charles Dowding
Northwestern University
847-491-4338
c-dowding@northwestern.edu

Chuck Howe
Geotechnical Engineering Section
Materials & Research Laboratory
MNDOT
1400 Gervais Avenue
Maplewood, MN 55109
612-779-5602

Darren Pleiman (City of Las Vegas project)
Kleinfelder Engineers
6380 Soputh Polaris Ave
Las Vegas, NV
702-736-2936 ext 107
dpleiman@kleinfelder.com

Gary Johnson
Regional Transportation Authority
Clark County Nevada (Las Vegas Project)
702-676-1500

Prof. Catherine Aimone (State regulatory project & NMDOT project)
New Mexico Institute of Technology
Soccoro, NM, 87801
505-835-5346
caimone@mailhost.nmt.edu

Alvin Budd
Vice President of Administration
GeoSonics
PO Box 779
Warrendale, PA 15095
724-934-2900

Larry Corneius
President, LARCOR
OEM White Seismographs
Quinlan, TX
903-356-2338

Ron Mask
Sales Manager
OEM Instantel
Kanata, Ont., Canada
613-592-4642

There are two main divisions of this project: 1) autonomous measurement of micro-inch vibratory and long-term crack movement and 2) autonomous graphical display of the results via the Internet. Its successes in 2) autonomous graphical display compliment and support other ITI Bridge Monitoring projects. For instance, instrumentation of the Sturgeon Bay Bridge is built around the concept of Internet display with the server software developed through this project.  With regard to micro-inch sensing, the ultimate goal is to cooperatively develop with GeoSonics and other manufacturers of vibration instruments a remotely operable and accessible instrument to measure micro-inch changes in crack width.

There are two main divisions of this work: 1) autonomous measurement of micro-inch vibratory and long-term crack movement and 2) autonomous graphical display of the results via the Internet. Successes in 2) has lead to the decision by ITI to incubate a spin-off company to commercialize autonomous graphical display called Civil Data Systems. With regard to micro-inch sensing, the ultimate goal is to cooperatively develop with GeoSonics and other manufacturers of vibration instruments such as Instantel a remotely operable and accessible instrument to measure micro-inch changes in crack width.

Specifically, the micro-inch instrument allows comparison of changes in crack width from weather and environmental effects (long term) with those from construction vibration (short term). Such a simple comparison is urgently needed as the general public has too little ability to understand the abstract complexity of the current system of control by measurement of ground motion. The public is interested in cracking, not abstract comparison of time histories of ground motion. They feel vibration but do not sense the long-term weather response. Thus some mechanism is needed to allow the neighbors of traffic and construction vibration to compare these two phenomena, both of which produce strains that can lead to cracking.

Industrial and regulatory interest in this concept is strong. Formal coordination of parallel codeployment efforts with GeoSonics, a world leader in the manufacture of vibration monitoring instrumentation, demonstrates the potential for its immediate application. For instance, a beta test model for on-site polling has already been deployed by GeoSonics for one of their clients. Vulcan Materials Corp. has loaned ITI the use of a home (adjacent to one of its quarries) for use in the development of the ACM system. ACM on site polling equipment was integrated with White Industrial Seismographs in a nation-wide study of the response of atypical structures. Plans are underway at Instantel to develop ACM capability in conjunction with ITI.

Task 1: Develop Milwaukee as Test Bed for Instrumentation

Negotiations with Vulcan will be completed for new a installation in the test structure in Franklin, WS, and the GeoSonics instrument will be installed along side of ITI developed ACM instruments for comparison. It is anticipated that at the end of calendar 2004 an Instantel machine will also be placed across the test crack.

Task 2: Prepare a guideline suitable for acceptance by ASTM

One of the pathways to commercialization is the acceptance of a guideline for installation. The current process for comparing various micro-inch displacement devices developed by ITI will be adapted for nomination as a guide through ASTM. This task will require both technical and administrative efforts.

Task 3: Negotiate with NYC authorities and develop installation protocols

Use of ITI ACM technology may assist the construction of two mega transportation projects which are scheduled to begin within the next year or two in New York City. They are the Long Island Connection to Grand Central Station, and construction of a major subway connector at 52nd Ave. The PI has been in communication with the vibration control engineer for the projects about the use of instrumentation to allay the concerns of building owners concerning the vibrations to be caused by the rock blasting necessary for these two projects. Over the years New York City has drifted into the camp of disallowing blasting; however, neither of these projects can be economically undertaken without blasting.

October 1, 2003– September 30, 2004

Task 1: Develop Milwaukee as Test Bed for Instrumentation - Fall 2003 and Winter 2004

Task 2: Prepare a guideline suitable for acceptance by ASTM - Spring 2004

Task 3: Negotiate with New York City authorities and develop installation protocols - Summer 2004

Total Costs- Current Year: $288,127
- Federal Share:               $115,272              5-Year Federal Share Total: $475,672
- Matching Share:             $172,856

Graduate Students:

- Markian Petrina, PhD student
- Remi Baillot, MS student

Undergraduate Students:

- Luc Griffith
- Dennis Kou

Continuation of "Commercialization of Instrument for Micro-Inch Measurement of Crack Width in Support of Thrust in Remote Monitoring for Bridge Management"

A specific user group in the field of construction vibrations has been developed. This group is connected via the Constvib listserve that is accessed through the ACM web site: http://www.iti.northwestern.edu/acm/. This group is some 300 large and from time to time exchange messages concerning vibration issues of mutual interest.

The vibratory roller project with Las Vegas is an example of the usefulness of the Constvib listserve. At the same time Las Vegas was expressing an interest, there was unusually high Email traffic on the listserve about vibratory roller excitation. This traffic closed the circle of interest about the issue and helped focus the research and project.

Commercialization of micro-inch crack measurement technology (ACM) is being conducted by advertisement through the following channels: (1) technical journal articles, (2) instrumentation, vibration, civil, geological, explosives, quarrying, mining, and construction magazines, (3) direct marketing to operators through the co-deployment associate, Geosonics, (4) Northwestern University internet sites, and (5) short courses and seminars. As described above, all five of these channels are being pursued.

In addition a new thrust, development of a guide for qualification of micro-meter crack measurement instruments, is being prepared to begin development of an ASTM guide.

Publications and Presentations Oct 2002- Oct 2003

"Micro-meter Measurement of Cracks to Compare Blast and Environmental Effects", was given at the 29th Annual Conference on Explosives and Blasting Technique of the International Society of Explosives Engineers in Nashville, TN in February 2003.

"New Approach to Control Vibrations Generated by Construction in Rock and Soil", was presented at the combined 39th US Rock Mechanics Symposium and 12th Pan Am Conference on Soil Mechanics at MIT in June 2003.

"Measurement of Crack Response to Long-Term (weather ) and Transient (vibratory) Effects" by C. H. Dowding and L. M. McKenna accepted for publication by the Geotechnical and Geoenvironmental Journal of ASCE, September 2003.

"Effect of Blast Design on Blast Response of Cracks" was given at the 2nd Conference of the European Federation of Explosives Engineers, in Prague in September 2003.

This project has led the way to a new concept of Internet broadcast of instrumentation response for public consumption. Software developed for this thrust will be commercialized through the incubation of a start-up called Civil Data Systems and will be marketed to firms that monitor instrumentation on bridges and other critical infrastructure facilities such as dams, power plants, etc. Such Internet presentation provides a unique method of public interaction and education. However, critical to the realization of this public interaction is the expansion of resources expended in the area of knowledge management and server programming.

Cracking, Types of cracking, Traffic, Vibration, Vibratory equipment, Construction, Remote sensing, Internet, Instrumentation, Measurements, Monitoring, Infrastructure

A481

The ICCML as a Novel Teaching Tool to Improve Undergraduate Education and Student Learning of Civil Engineering

Roberta Massabò
Northwestern University
847-467-4105
r-massabo@northwestern.edu

The main educational goal of the project is to bring knowledge from the infrastructure / building industry to university curricula. Objectives of this project are the following.

1) Improve the web site developed in the previous project (basic expandable structure, additional material and new cas