A Conversation with John Buxton, Bridge Maintenance Engineer at Maine DOT

John Buxton with Maine DOT

Author: Lorella Angelini, Angelini Consulting Services, LLC
I recently spoke with John Buxton, Bridge Maintenance Engineer / Deputy Chief Engineer at Maine DOT.  He is in charge of the Bridge and Structures Maintenance Division at the Bureau of Maintenance and Operations. In addition, he is connected to the executive office as the Deputy Chief Engineer. John is fully committed to bridge preservation. His many years of experience in this field make him a go-to person with TSP2.

What does bridge preservation entail at Maine DOT?
Bridge preservation currently represents 70% of Maine DOT’s maintenance budget. While in the past we used to do a lot of rehabilitation and restoration type of work, currently preservation is the primary focus for the maintenance department. Preservation entails activities such as replacing and repairing joints, making sure that all joints are sealed, sealing concrete with water repellents, painting bearings and beam ends, and keeping concrete wearing surfaces in good condition. We are trying to address the deterioration of bridge elements before it becomes a problem. It is evident that it is better to spend a few dollars in preservation than thousands of dollars in restoration.

Does your 70% of maintenance budget include all preservation expenditures at Maine DOT?
In addition to maintenance, also the capital side has a budget for preservation activities, which mainly entail full painting projects. We are treating concrete with silanes, not only the deck but also vertical surfaces, such as piers adjacent to travel ways, back walls, and all exposed concrete.

The capital money is obviously not as aggressive in preservation as maintenance money. The capital side probably spends 25 – 30 % of their funds in preservation while the rest is reconstruction and bridge replacement.

Getting the capital people, who focus on new bridge construction, to invest funds on preservation activities has been a major shift in the way Maine DOT operates.  It is a combination of preservation, construction and reconstruction that allows maximizing investments for the bridge infrastructure.

What are the key points of the bridge preservation strategy at Maine DOT?
Our main strategy is to keep bridges in good condition by doing preservation activities. We are getting out of the “worst first” type of mentality, even though we continue to take care of bridges that are deteriorated beyond the practical maintenance point.

If you talk with other representatives from the TSP2 Bridge Preservation Partnership, you will find that they are using the same approach.

Do you have any statistics that show the benefits of a bridge preservation strategy?
The benefit of preservation is probably one of the hardest things to capture. For example, when you seal concrete it is hard, almost impossible to predict, whether the concrete is preserved for 20 or 25 years. In terms of NBI Bridge Inspection Ratings, when you seal the concrete of a pier, you do not change the rating of the pier. Let’s say the pier is in a condition state 6. By sealing the concrete you hopefully have kept the pier in that condition state for a longer time, which does not show up in graphs or statistics. It is really difficult to quantify the benefits of preservation actions.

Is it challenging to convince people of the benefits of preservations?
Yes, building a new bridge always carry the headlines. However, the political flavor has changed in Maine and around the Nation. People understand that it is worth preserving bridges, especially when they see the tremendous cost for a new bridge. Spending a fraction of that cost to do actions that can preserve an older bridge and get 30 – 40 more years of life out of it is evidently the proper way to go in most cases.

What are your goals with bridge preservation?
In line with the National Highway System guidelines, our primary goal is to eliminate all condition 4 , corresponding to poor condition, for bridge elements.  However, our goal is not only based on numbers but also on a case by case evaluation. Let’s say that we have an abutment that is in a condition state 4. It does not mean that the abutment is unsafe. It just means that the abutment is not in a good condition. It may have been in that condition for 20 years and it may be able to provide another 10-15 years of service life in that condition. Sometimes it is necessary to be aggressive on a bridge element, sometimes not.  What is important is to evaluate the impact of the element on the functionality and the safety of the bridge.

Can I say that that you are in favor of a selective approach?
If you just look at numbers, they are pretty sterile; they do not tell you the whole story. It takes skilled, talented, knowledgeable professionals within each State Agency to evaluate risks related to the condition state of bridge elements. To be able to quantify and qualify these risks is a key knowledge that ultimately keeps public safe.

You do not want to spend funds just to make the numbers look good.  You want to do the right thing for your bridge inventory.  If you can postpone expenditure for 15 years without jeopardizing safety and function, then this is the right thing to do in my opinion.

Who takes decisions related to bridge elements at Maine DOT?
We take decisions in a bridge committee that comprises of three legs: bridge maintenance, bridge design and construction, the so called capital program, and bridge management. It is what we call Maine DOT’s bridge community.  We know each other. A lot of us have worked together for as long as 30 years.

I am also part of a posting committee at Maine DOT that takes decisions on bridge weight restrictions. If a bridge does not meet a certain level of capacity based on bridge ratings, we evaluate whether we post the bridge or we strengthen it. In some cases, we do research, such as load testing, cutting coupons out of the steel to see if it is still strong, or cutting reinforcement steel in concrete to see strength can be added.

Some posting can be restrictive thus impacting community and commerce.  Bridges in rural areas usually need fewer restrictions since they just carry fire trucks and light vehicles. Even though many bridges in Maine are in good condition, they were designed 60 years ago for a much lighter type of vehicles.  Over 50% of Maine bridge inventory is more than 50 years old.

We spoke of the challenge of making people aware of bridge preservation benefits. Are there other major challenges?
The availability of experienced, qualified workers is another major challenge for bridge preservation. Craft people are not readily available as they once were. This challenge is not peculiar to Maine but rather a nationwide issue.

Do you do in-house maintenance work?
Two years ago Maine DOT started contracting maintenance jobs out. We had more money for maintenance than in the past but not enough people to do the job. We therefore decided to contract out using those additional funds. It was a little clunky at first because we had never contracted jobs out before.  The capital department had always done all the contracting for bridges at Maine DOT. We had to learn how to put out contracts and they are small contracts, generally under $200,000.

With the increased funding, do you have enough money for all preservation work at Maine DOT?
In 2007 and 2014 we developed two reports called “Keeping our Bridges Safe” (see Linkage – Ed. Note). Those reports recognize the need of spending $140 M/year for bridge preservation. However we get on average $105 M/year. As a result of being we remain $30 – 40 M/year short of spending requirements, at Maine DOT we are accumulating a spending deficit of $90 – 120 M in the length of time of 3-4 years.

Is there any bridge preservation success story you would like to share?
I think our biggest success story is that the entire bridge community at Maine DOT is on board with bridge preservation and really sees the value of it.

Painting may not improve the NHS condition rating of a superstructure, sealing concrete may not improve the NHS condition rating of a substructure; however these are important actions to keep bridges in a good condition. As an analogy, regularly changing the engine oil does not modify the way one drives a car but it makes a big difference in the longevity of the cars’ engine.

Does TSP2 assist you in reaching your bridge preservation goals?
I remember when Ed Welch from New Hampshire DOT, Pete Weykamp from New York DOT and Everett Barnard, my predecessor at Maine DOT, used to meet in New Hampshire with maintenance personnel. These three people first recognized the need for bridge preservation to have its own forum. So my hat goes off to them for pushing the preservation idea and setting up the conditions for having the Partnerships.

To me every year TSP2 Bridge Preservation meetings are better. Communication between bridge preservation practitioners is improving and we have more proficient people representing manufacturers. I can call up a number of engineers that are part of the Partnership and ask: have you tried this? Have you got this problem? What do you do to solve it? The network is just phenomenal.

There is a great value for bridge preservation practitioners to connect with product manufacturers’ people at the TSP2 Bridge Preservation Partnership meetings. Bridge practitioners can speak with different manufacturers and compare their products. There is also an opportunity for competitors to confront their products. Manufactureres also have avenue where they can speak with each other and potentially start collaborations for putting together different products and technologies in order to solve bridge preservation problems. TSP2 sets the stage for creating synergies between product manufacturers.



Maine DOT

“Keeping Our Bridges Safe” 2007

“Keeping our Bridges Safe” 2014

Reports from the MWBPP Working Groups

Author: Lorella Angelini, Angelini Consulting Services, LLC

At the recent TSP2 Midwest Bridge Preservation Partnership (MWBPP) meeting that took place in Minneapolis, the Working Groups met to discuss the status of their activity and outline future developments.  I asked the leaders of the Working Group meetings in Minneapolis if they could write a summary for the Blog.

Preservation Matrix: Dave Juntunen, Michigan DOT

Dave Juntunen with Michigan DOT

The working group concurred that the preservation matrix is still desired and the working group should be continued. New members volunteer.

The current deliverable of the working group is an Excel spreadsheet showing what preservation activities the partner states do by contract and state maintenance forces. Unfortunately few people ever see the matrix or even know of its existence. The group would like to update the matrix and make it available to the bridge preservation community by placing it on the on the TSP2 MWBPP website. The matrix should be updated to include links to training and state specifications. Analysis of the matrix can be done to show trends in preservation and a blog written to introduce the website and provide outreach to partner states and local agencies.

Systematic Preventive Maintenance (SPM): Scott Stotlemeyer (chair), Missouri DOT

Scott Stotlemeyer with Missouri DOT

25 attendees met to discuss the current and future scope and deliverables of the MWBPP’s Systematic Preventive Maintenance (SPM) working group.   The working group serves to collect information regarding member states’ status in having an FHWA-approved SPM program.  The working group delivers a synthesis of member states’ participation in a program and any SPM-related information (e.g., contacts, agreements, guidelines, etc.) they are willing to provide on a triennial basis.  The last of which was released in November 2016 and is available through a link on the “MWBPP Working Group” page of the TSP2 Bridge Preservation website.

Those in attendance agreed the working group’s scope and deliverable were still relevant, as some member states were still working on developing or improving their SPM program and the information provided was of benefit to them.  In addition, attendees expressed their interest in a list of potentially eligible SPM activities – possibly ones preapproved by FHWA for inclusion in an SPM program.

Additional discussion within the group involved guidelines, processes, and equipment used to perform SPM activities with in-house forces and specifications for performing SPM activities through contract under an SPM program.

Deterioration Modeling: Fouad Jaber (chair), Nebraska DOR

Fouad Jaber with Nebraska DOR

12 people attend the working session.  The discussion went in the direction of continuing this effort.  Fouad will contact member states to find out their practices and needs for deterioration models.  We may create a pooled fund to address MWBPP State needs and bridge the gap between BrM and states practice. A survey will help focus the effort to what is needed.  The National efforts (BRM and LTBP) as well as individual state tools will be considered.  Hooman (Rutgers) from the LTBP will help with access to the LTBP Portal.   The survey will also identify the appropriate person in each state that we should coordinate with.  We may use pooled fund to reduce the data.  There will be a conference call in near future with Working Group to set up the survey




A Conversation with Judith Corley-Lay

Judith Corley-Lay, Director of NCPP

Author: Lorella Angelini, Angelini Consulting Services, LLC

In April 2017 Judith Corley-Lay took the leadership of the National Center for Pavement Preservation team thus succeeding to Larry Galehouse after his retirement.  Judith comes to NCPP and TSP2 with an impressive track record.

She started her career teaching Civil Engineering at the University of Texas in Arlington focusing on geotechnical engineering, contactor specifications and engineering economics. After several years with the University of Texas, she joined Texas A&M (Agricultural and Military) where she thought for two years and was also appointed to the staff of the A&M Transportation Institute. When her husband took a position at the University of North Carolina, she relocated to North Carolina, where she started working in the pavement management unit at North Carolina DOT (NCDOT).  For 26 years, up until her retirement in September 2016, she developed an extensive knowledge of pavements, including design, data analysis, field data collection, and pavement management systems.

When Larry Galehouse left the National Center for Pavement Preservation (NCPP), she decided to step out of retirement and apply for his position. She is now employed by Michigan State University (MSU), working from North Carolina where her family lives.   When I asked her about the decision to apply for the position as Director of NCPP, she told that it came from the realization of the great value of the TSP2 Partnerships, her desire to continue their activity and contribute to their success. In her work at NCDOT she has had first-hand interaction with the South-East Pavement Preservation Partnership (SEPPP) that brought her a huge amount of benefit.

Can you speak of the challenges of continuing the job started by Larry Galehouse?

When you are taking over from somebody like Larry, who had led an organization from the beginning, it is a daunting task. While I know a lot about pavement preservation, I am putting a lot of emphasis on becoming knowledgeable in the areas of bridge preservation and equipment management. For this reason I made the commitment to attend every Partnership meeting for at least first year. This allows me to learn first-hand about how the different groups work.  

Michigan State asked me to increase the research activity for bridges, pavements and also equipment. In collaboration with John Hooks, who is an excellent writer and editor, we wrote a proposal for accelerated bridge preservation for Michigan DOT. The proposal was accepted. This, was really good because (NCPP) had not had any research for Michigan DOT in several years.

One of the complications of my job is that you really have to balance the activities the Partnership focuses on with the activities from the University and the Oversight Panel. These activities are not always coincident.

What can you tell about the activity from the Oversight Panel?

The Oversight Panel is chaired by George Conner from Mississippi DOT, who is also the chair of SCOM, Sub-committee on Maintenance. The Oversight Panel represents AASHTO in overseeing the TSP2 program by NCPP. We answer to AASHTO that legitimately wants to know how expenditures into the program are being used.

During the last session the TSP2 Committee came up with the idea of funding small research projects with the Partnerships. While half of TSP2 excess balance is used for future operations, TSP2 wants to spend the other half on operations related to activities through the Partnerships. We are going to ask the Partnerships to submit research ideas. Then a few of these ideas will be chosen and funded to the level of contribution already submitted by the States.

Excess fund comes from the States’ voluntary contributions to TSP2. These contributions fund two people to come to the regional Partnership meetings for both pavement and bridge preservation. A little carries forward every year thus building up an excess fund that we want to spend down doing research for the Partnerships.

NCPP is a Center at MSU. I have an appointment to the faculty of MSU even though I do not teach. NCPP is under contract with AASHTO to manage the TSP2 program, which includes all of the Partnerships for both pavement and bridge preservation. That is how everything is linked. One of the reasons NCPP was chosen by AASHTO is its ability to develop good relationships between the vending community and the Agencies.

TSP2 has indeed created a strong dialogue between state DOTs and vendors that was almost unthinkable some time ago. Could you comment about it?

TSP2 has been successful and innovative in establishing a relationship between Agencies and vendors, such as manufacturers, contractors and consultants.

Partnership meetings are set up with specific guidelines about the conversation cannot be about any project up for bid. This fundamental rule makes it possible for State agencies to talk with the vending community and have a really good conversation. You hear people talking: “What about this type of application?” or “I tried this, I had this problem, what do you suggest?” These conversations could not take place if they were related to contract projects.

Going back to your TSP2 appointment, could you provide some details about what your job responsibility entails?

I am focusing on three areas. One is overseeing the day by day operations, making sure that routine operations run smoothly. Another area concerns the development research programs, as I explained before. The third focus area, which is very important for me, entails increasing the activity with local Agencies, such as Counties, Municipalities, and Cities.

I recently spoke at the American Public Works Association (APWA) for the North Carolina chapter and at the asset management conference through the Michigan Local Technical Association Program (LTAP) in order to promote the concept of preservation and increase contacts between TSP2 and local Agencies.  

It is important to promote the preservation message. We should underscore the advantages that preservation brings to the community starting from tax dollars savings, especially in the long-term.

Spreading the preservation message also keeps the new leadership at state and local Agencies informed and knowledgeable about preservation. Agencies turn over leaderships every 4 years on average, which means that they are always in a training mode at some level.

What is your vision for bridge preservation?

Agencies must move beyond the Structurally Deficient (SD) bridge concept as they define their plan of action. If Agencies only focus on repairing or replacing SD bridges, there will likely be a huge wave of bridges moving from fair conditions to SD in the near future.  

Unfortunately, the MAP-21 legislation retained and amplified the focus of DOT Agencies on SD bridges since FHWA took SD as the measure for bridge performance in MAP 21 legislation. Definitively, focusing investments solely on SD bridges is not a sound strategy.

I think that focusing on SD bridges also leads the bridge preservation conversation in the wrong direction.

We have a great talent pool in the bridge preservation area. Practitioners are knowledgeable and passionate about their work. They know their inventory and they understand what it takes to keep the inventory working but we cannot give them value as long as SD remains the key topic.

Could you point out key challenges for bridge preservation?

As I said before, MAP 21 and its focus on SD bridges is a challenge. Another significant challenge entails the very large number of retirements that are happening at the state Agencies. Gap in experience is developing not just in the Agencies but also in the contractor community.

After the completion of the Interstate highway expansion in the 90’s, for approximately a 15-year period there was not much hiring. When people in their 60’s with 30 years of experience are now retiring, we replace them with people who have only 15 years of experience. There is a 15-years gap, which is huge in bridge preservation because preservation requires experience. Its knowledge is based on seeing problems and trying solutions. In spite of knowledge sharing at the Partnerships, it is only after a decision is played out in practice that one can know if it was correct or no.

This is not a reflection on the younger generation that is sharp and bright. I have a lot of faith in the younger generation given they have the time to develop some expertise. I am confident they will be able to move the bridge preservation issue to another level.  

What gives you the most satisfaction in your work?

There are two aspects of my work that I find most satisfactory. One is coming to the regional Partnerships meetings and hearing bridge practitioners being so honest about strengths and weaknesses of their program. They are inspiring with their honesty. The other aspect is of course the staff at the NCPP, who are wonderful people I enjoy working with. I respect their level of commitment. They really want everything to be perfect, which makes my job a joy.


APWA North Carolina Chapter

Michigan LTAP 

A Conversation with Kevin Irving with AZZ Metal Coatings

Kevin Irving with AZZ Metal Coatings

Author: Lorella Angelini, Angelini Consulting Services, LLC

Steel corrosion tops the list of bridge preservation problems. It shortens the service life of bridges and can pose a safety issue. Once corrosion has started, it is very difficult, almost impossible, to stop it. In the US 40% of carbon steel is used to replace corroded steel at a cost of $425 B corresponding to approx. 2.5% of the GDP. This cost does take into consideration the additional cost related to suspending or limiting the use of steel damaged infrastructures.

Galvanized steel is being increasingly adopted by DOTs as a mean to protect structural steel from corrosion. To know more about this growing technology I spoke with Kevin Irving, National Marketing Specialist with AZZ Metal Coatings.

Kevin, who is based in the Chicago area, has more than 25 years of experience in the Hot-Dip Galvanizing (HDG) industry. He has many qualifications, such as being a certified coating inspector by the NACE International and a certified presenter of the American Galvanizers Association (AGA). He currently serves as a National Board Member for the Chemical Coaters Association International (CCAI) and as a member of the TRB Bridge Preservation Committee. He is industry director for the Western and Midwest TSP2 Bridge Preservation Partnerships.

What are the benefits of HDG for bridge preservation?

HDG increases bridge safety while reducing maintenance costs. It consists of applying a protective zinc coating to steel thereby preventing rusting and deterioration of the steel. Since zinc corrodes up to 30 times slower than steel, galvanizing dramatically reduces steel corrosion. Zinc adheres to steel through the metallurgical bond provided by HDG.

What are major differences between galvanizing and other technologies for steel protection, such as metalizing and painting?

Galvanizing, metalizing and zinc-rich paints all provide barrier protection to the underlying steel. What separates galvanizing from the other two technologies is the fact that galvanizing provides a metallurgical bond between zinc and steel, creating three zinc-iron alloy layers and a nearly pure zinc outer layer. Instead, metalizing and paints provide a mechanical, not a metallurgical bond, between coating and steel. The mechanical bond is generally considered as a less performing bond when compared to the metallurgical.

All three technologies provide cathodic protection to the underlying steel although some types of zinc-rich paint provide less protection than others. If the coating gets scratched thereby exposing the steel, the zinc will preferentially corrode to protect the exposed area. HDG has the advantage of preventing scratches in the first place. In fact, the zinc-iron alloy layers created during galvanizing are harder than the base steel, making HDG much more abrasion resistant than other coatings.

Can HDG be considered an innovative technology?

HDG is a very good technology with an exceptional track record but it cannot be considered as an innovative technology. Some applications like the I-69 bridge northbound lanes near Indianapolis, the Stearns Bayou Bridge in Grand Haven, Michigan and the Ford County Bridge in Illinois were completed almost 50 years ago.  These three bridges represent a success story since no maintenance has been needed to date and another 30 years of service life should be expected for all of them.

Continuous-Galvanized Rebar (CGR) per ASTM A1094 produces a galvanized rebar with a pure zinc alloy coating structure.  Although the continuous galvanizing process has been used for decades on galvanized automotive steel, its application to rebar is new. The CGR process allows long lengths of rebar sizes to be stored for fabrication and then formed without cracking, peeling or flaking, and without requiring special equipment for forming.

The CGR coating passivates faster and corrodes at a slower rate than traditional HDG coatings. The CGR process is automated and faster, resulting in quicker lead times, repeatable quality and consistency in the coating.

CGR can also be dual-coated with epoxy to produce a duplex coating according to ASTM A1055 specification.  The additional epoxy barrier over CGR provides an affordable belt and suspenders approach for most extreme environments.

Is galvanizing an expensive technology?

According to Philip G. Rahrig, executive director for the AGA, the cost for HDG is approximately $1.76 per square foot. This cost should be slightly less for large tonnage jobs.

What are the fields of application of galvanizing technology?

The technology is widely used for steel structural elements, such as beams and rebars in reinforced concrete. It is also used for guard rails, street signs and posts.

Could you briefly describe the galvanizing plant process for a steel beam, for example?

In the HDG process, the steel beam comes to the galvanizing plant after being manufactured and prior to service. The first step of the process entails an inspection to check that no paint, mill markings and heavy grease are present on the steel surface. After the inspection the beam goes to a caustic degreasing bath to remove any grease, grime, oil, or dirt. Once rinsed in a water bath, the beam is immersed in an acid tank or pickling bath so as to remove of any mill scale or rust oxide. This is also followed by water rinsing.

After cleaning, the steel beam is immersed in a flux tank. The flux is a combination of zinc, ammonium and chloride. At 160 degrees Fahrenheit, the flux bath deposits a light coating on the steel, which keeps it from oxidizing. The flux bath also preheats the steel.  In the next and final step of the process the beam is submerged in a galvanizing kettle. This bath must have a minimum of 98-percent pure zinc to meet ASTM A123 requirements.

The galvanizing kettle is heated to a temperature ranging from 830 to 840 degrees Fahrenheit, at which point the zinc is in a liquid state. The steel beam remains in the zinc bath until the steel reaches the bath temperature. When the beam comes out from the kettle, the zinc coating must have a minimum thickness of 3.9 mils for steel more than 1/4-inch thick (ASTM A123).

It usually takes approximately three hours to complete the process from beginning to end. The steel is typically immersed in the molten zinc in the galvanizing kettle for less than 10 minutes. There are currently more than 75 plants in the United States that can provide galvanizing for steel elements for bridge construction.

What are the challenges in the HDG process and the steps to ensure it is properly done?

It is extremely important to check placement and number of vent and drain holes prior to the galvanizing bath. This ensures safety during immersion of the steel in the molten zinc by allowing pressure to escape from air and moisture present in internal sections of fabrications. It also allows the molten zinc to contact and form the HDG coating on all internal and external surfaces. Vent and drain hole requirements are outlined in ASTM A385.

It is also preferred that the piece is completely fabricated before being galvanized so as to avoid welding after the galvanizing process.  If welding is needed after HDG, the zinc must be burnt off with a torch or ground off until there are sparks in order to be sure that the steel substrate is reached.  Upon completion of welding, it is necessary to restore corrosion protection on the area where the galvanizing was removed and on the weld.

It is good practice to communicate with the galvanizer prior to design and fabrication. This provides the best opportunity to address design details that could affect the formation of the HDG coating.

Can you share a case study?

The Stearns Bayou Bridge in Grand Haven, Michigan, was galvanized and installed in 1966. The steel is in very good conditions without having required any maintenance from the time of construction.

This county bridge is 430 feet long with a 30-foot clear roadway and a 5-foot walkway along each side. The majority of the steelwork is 6 feet above a freshwater river in a rural location. The bridge experiences light to moderate traffic and the entire bridge is subject to winter salting.

After 51 years following the construction, all the beams and diagrams are in very good shape showing no signs of rusting or staining despite the fact that the bridge is subjected to snow and deicing salts. The average zinc coating thickness is 5.4 mils, which indicates that HDG will continue to provide corrosion protection for decades in this environment. All bolted connections also show no signs of rust.

However, in five places on the tubular rails on the top of the bridge there are signs that the zinc has been completely consumed thus exposing the metal substrate. The preservation process for these areas simply requires applying a zinc rich paint over the exposed steel.  The rest of the rails should be power washed with some type of salt mediation and painted over without sandblasting on a completely dry surface. Standard specifications (ASTM D6386 and SSPC Guide 19) must be used as guidance for the paint application.



AZZ Metal Coatings https://www.azz.com/metalcoatings

You Tube video from AGA: “Hot-Dip Galvanizing: Protecting Steel For Generations” https://www.youtube.com/watch?v=kwCyq06aatA

You Tube video from GalvanizersAssocAus: “Hot Dip Galvanized Steel – What, How & Where” https://www.youtube.com/watch?v=c2J07n5hSbs

You Tube video: “AZZ Galvanizing Overview”

You Tube video: “AZZ Galvanizing Workflow”

A Conversation with Jeffrey Milton with VDOT

Jeffrey Milton with VDOT

Author: Lorella Angelini, Angelini Consulting Services, LLC

Jeffrey Milton, Bridge Preservation Specialist with Virginia DOT (VDOT), is a bridge preservation leader in his State and at national level.

Jeffrey is member of the AASHTO Subcommittee on Maintenance chairing the Technical Working Group on Bridges. He is also part of the FHWA Bridge Preservation Expert Task Group and actively involved with TRB and NCHRP, where is covers a number of Committee Memberships.

  • TRB Standing Committee on Structures Maintenance – AHD30 Member
  • TRB Standing Committee on Bridge Preservation – AHD37  Member
  • NCHRP Project Panel on Development of Guidelines for Uniform Service Life Design for Bridges D12108  Chair
  • NCHRP Project Panel on Condition Assessment of Bridge Post-Tensioning and Stay Cable Systems Using NDE Methods D1428  Member
  • NCHRP Project Panel for Extending the Life of Highway Bridge Coating Systems Through the Use of Spot Painting with Minimal Surface Preparation D1430  Member

Jeffrey is a member of the FHWA Technical Panel for update of NHI Bridge Maintenance Training Course and development of NHI web-based Bridge Preservation Training Course. He is also member of the TSP2 oversite panel.

I recently had the opportunity to speak with Jeffrey about VDOT bridge preservation program.

How does bridge preservation fare at VDOT?

Using Virginia structure data as of September 1, 2017, the total number of structures in Virginia inventory sums up to 21,124, of which 13,113 bridges and 8,010 culverts. Out of these structures, 19,469 entail VDOT owned/maintained structures, of which 11,910 bridges and 7,559 culverts. The number of city, county and town owned/maintained structures is 1,463, including 1,044 bridges and 419 Culverts

VDOT defines Condition Categories for structures as Good, Fair and Poor.

  • Good Condition means a low General Condition Rating of 6 or greater
  • Fair Condition: a low General Condition Rating equal to 5
  • Poor Condition: a low General Condition Rating of 4 or less

Condition Categories for the 19,469 VDOT Owned/Maintained structures currently report a limited number of structures in Poor Condition.

  • 13,891 (71.3%) of the structures are in Good condition
  • 4,818 (24.7%) of the structure are in Fair condition
  • 760 (3.9%) of the structures are in Poor condition

What does bridge preservation entail at your DOT?

At VDOT bridge preservation is part of a comprehensive Bridge Program that includes preventive and restorative maintenance, painting, rehabilitation and replacement.

Examples of preventive maintenance are bridge cleaning, deck sealing, sealing joints, thin deck overlays and spot and zone painting.

Restorative maintenance includes deck patching, rigid deck overlays, reconstructing/closing joints, superstructure repairs, substructure repairs, fatigue retrofitting, scour repairs, cathodic protection and electrochemical chloride extraction.

Painting encompasses spot and zone painting, over-coating, complete removal and repainting.

Superstructure replacements, deck replacements and culvert rehabilitation are examples of rehabilitation. Rehabilitation and replacement are not part of VDOT Bridge Preservation Program, which focuses exclusively on preventative maintenance, restorative maintenance and painting.

What criterion does VDOT use to determine actions that should be implemented?

Our criterion can be outlined in three points.

  • Preventive maintenance candidates are structures in Good Condition (a low General Condition Rating of 6 or greater)
  • Restorative maintenance candidates are structures in Fair Condition (a low General Condition Rating equal to 5)
  • Rehabilitation and replacement candidates are structures in Poor Condition (a low General Condition Rating of 4 or less).

We also use element level condition states and defects to develop specific maintenance and preservation treatment options.  We previously used AASHTO Pontis for our bridge Management system, and we are now investigating the use of AASHTO BrM.

As a general guideline, we want to make sure that preventive, painting, and restorative works are performed before the onset of serious deterioration while the structures are still in good or fair conditions.

We adopted a breakdown for the allocation of bridge structure funds that foresees 15% for preventive maintenance, 10% for painting, 25% for restorative maintenance and 50% for rehabilitation / small structure replacement. This balanced breakdown helps select efficient and effective actions, as it is essential in order to maintain a healthy bridge structure inventory.

Can you outline key bridge preservation strategies at VDOT?

Some VDOT structure/bridge preservation strategies include:

  • Eliminate deck expansion joints. The designer must evaluate the feasibility of joint elimination. When elimination is not possible, the designer will have to submit justification, including supporting calculations, to the Assistant State Structure and Bridge Engineer for Maintenance.
  • Reconstruct concrete adjacent to joints and install strip seals. When joints cannot be practically eliminated, specific activities should be performed such as perform concrete substructure surface repair and apply waterproofing coating/treatment to pier and abutment seats and ends of beams/girders.
  • Install asphalt plug joints with back-up sealers on decks having asphalt overlays.
  • Prepare concrete decks using hydro demolition and place rigid concrete overlays.
  • Coat beam ends and substructure caps under joints.

What challenges have VDOT encountered in the implementation of bridge preservation strategies?

Like many Agencies, our corporate culture has previously taken a worst first approach to the bridge program, with major emphasis on structurally deficient structures.  We have made great progress with our management in promoting a preservation approach focusing on preventive, painting, and restorative works for extending the service life of our inventory.

Can you inform of new technologies that have been recently adopted by VDOT?

We have started using hydro demolition and placement of rigid concrete overlays to protect the concrete deck. We are also investigating the use of hydro-demolition and hydro-milling for concrete removal on substructures.

VDOT Structure and Bridge Division and the Virginia Transportation Research Council are investigating the use of remotely operated data gathering devices and remotely operated maintenance devices. These devices, which include Microsoft HoloLens, unmanned aerial vehicles (drones) and crawling devices designed for bridges and culverts, can be outfitted with various sensing technologies, such as infrared, high resolution cameras and impact (sound).

We are in the process of conducting a research project in order to investigate the use robotic devices in conjunction with lasers for the removal of paint from steel beams and girders.

How can TSP2 help VDOT reach its goals?

TSP2 provides a very valuable platform for sharing information of treatment methods, best practices and research projects among the States, especially when participating in regional and national working groups.  The TSP2 staff provides support to the preservation program in Virginia and throughout the nation.



Chapter 32 of the VDOT Manual of the Structure and Bridge Division (File 32.01-9-12) shows the VDOT Bridge Planned Preventive Maintenance Program.  A link to this document follows: http://www.virginiadot.org/business/resources/bridge/Manuals/Part2/Chapter32.pdf

VDOT is in the process of reviewing and updating this document (Ed Note).

A link to the FHWA Bridge Preservation Guide follows: https://www.fhwa.dot.gov/bridge/preservation/guide/guide.pdf

This guide will be updated by the FHWA Bridge Preservation Expert Task Group (Ed Note).

Emphasis on Case Studies at the MWBPP Meeting in Early November

Author: Lorella Angelini, Angelini Consulting Services, LLC

Bridge preservation case studies will be featured at the 2017 Midwest Bridge Preservation Partnership (MWBPP) meeting held at the Marriott City Center in Minneapolis, MN on November 6-8. The meeting will also focus on actions for deck and joint preservation and emergency response procedures for exceptional events, such as flooding, bridge hits and fire.

Bridge preservation practitioners attending the meeting represent the States that are part of the Midwest TSP2 Partnership region: Illinois, Indiana, Iowa, Kansas, Kentucky, Michigan, Minnesota, Missouri, Nebraska, North Dakota, Ohio, Oklahoma, South Dakota and Wisconsin. At the meeting preservation practitioners from DOTs and other owners will be interacting with contractors, consultants, academia and manufacturers that have a stake in bridge preservation in the Midwest region. Manufacturers will also have an opportunity for showcasing their products and technologies.

As with all TSP2 Bridge Preservation Partnership meetings, time will be dedicated to round tables where owners, consultants, academia, manufacturers and contractors can exchange information related to their experience with bridge preservation, underscoring challenges and solutions for extending the service life of concrete and steel bridges.

MWBPP mission is to provide a platform for bridge preservation practitioners to exchange, promote and advance best practices, new technologies and innovation in the areas of highway bridge management, inspections, preservation and maintenance.

For information please contact Darlene Lane at 517-432-8220 and email hidden; JavaScript is required


2017 MWBPP Annual Meeting

A Conversation with David Miller, Chief Maintenance Engineer with Louisiana DOTD

David Miller with LaDOTD

Author: Lorella Angelini, Angelini Consulting Services, LLC

About one year ago, David Miller was promoted to the Chief Maintenance Engineer position at the Louisiana DOTD (LaDOTD). Before that he served for several years as the Bridge Maintenance Engineer for the State. David is happy his new position gives him the opportunity to remain involved with the bridge program and he can take preservation issues further. 

As Chief Maintenance Engineer David Millers’ responsibilities include managing the ferry systems, signs and signals, bridge inspection, loss prevention and truck permits.  He is also in charge of the statewide bridge crews that work on complex preservation projects and the statewide crews that specialize in putting up signals and sign trusses. On the other hand, the crews that carry out the day-to-day work for the maintenance of bridge and road assets are managed by the nine LaDOTD Districts

Some of the longest bridges in the United States are located in Louisiana. With 175,000,000 square foot of deck area (2016 FHWA data), Louisiana ranks as the fourth largest state for bridge deck area. It follows Texas, California and Florida, which all have a higher number of bridges than Louisiana. In addition to having long bridges that span over the Mississippi and across marshlands, Louisiana has also a large number of timber bridges (third most in the US), which were built years ago during the expansion of local timber industry.

What does bridge preservation entail at LaDOTD?

Bridge preservation can be divided in two parts in Louisiana. One part entails larger preservation projects that are managed through the bridge preservation program that has been in place for about 10 years. It is part of the overall bridge replacement, bridge rehabilitation capital program and allocates from $30 to $40 M per year specifically for bridge preservation projects. Projects are selected through a committee that takes input from the districts and are back checked with deterioration models from Pontis in the past, AASHTO BrIM currently.  This part is where the heavy lifting on the preservation side comes in.

The other part is funded through the operating side of the budget. This entails maintenance and preservation activities that are done by districts’ bridge crews and statewide crews. Unfortunately, our crews tend to do more emergency-related work than preventative maintenance because many bridges in Louisiana are in poor condition. (In 2016, LaDOTD reported 1,739 structural deficient bridges, corresponding to 13.5% of 12,915 total number bridges. Ed. Note). Our crews also focus on preserving our timber bridges to keep them open and safe.

What is your bridge preservation strategy?

Our strategy at LaDOTD is to improve the condition of bridges and their ratings every time it is possible. For example, if a paint project is scheduled for a particular bridge, we do not necessarily want to do the painting only. We evaluate whether there is a structural rehabilitation project that can be done in parallel to painting to improve the overall rating of the bridge. A pure painting project does not move the rating of a bridge from poor to good.

The majority of our preservation activities have been focused on bridges that are in poor conditions. Our goal is to bring these bridges from poor to fair or from poor to good. Mainly because of lack of funds, we are not at the point that we can do activities on bridges that are in good condition, which is the recommended preservation approach.

Our gas tax, 16 cents per gallon, was implemented in the 80s and has not changed, or been indexed, since then.  We recently went through an effort with our Legislators to try to increase the tax in order to have more funds to maintain bridge and road assets. Unfortunately, this effort failed to pass. This will make our responsibilities in maintenance difficult to carry out as we continue to deal with our relatively large number of posted and structurally deficient bridges. It will take additional funds to be able to get ahead of the curve and do more of strategic preservation activities on our bridges.

Four of the top five longest bridges in the United States are in Louisiana. Most of these bridges belong to the interstate system and are in good shape. However, having to deal with long bridges puts an additional strain on our resources.  Preserving a bridge that is 20-miles long and has a twin structure requires a lot of money. A tremendous amount of money is required just to tackle one element of the bridge, for instance the deck.

What is the LaDOTD strategy with structurally deficient bridges?

We have prioritized work on structurally deficient and posted bridges that are on the major truck routes.

We are also planning to replace all our timber bridges.  This poses a challenge as we have the third most timber bridges in the country.  Most of these bridges, which were built in the 50’s and 60’s, are deteriorated beyond their service life.

What are the challenges in the implementation of your preservation strategy?

As I said before, the biggest challenge for us is funding. Our administration understands the need for additional funding for highway infrastructure, so hopefully there will be additional funding in the future.

Do you have a success story you would like to share?

Probably the biggest success story is just the fact that LaDOTD has a bridge preservation program that has been in place for 10 years. There have been some major projects completed through this program. One of these was the rehabilitation of Huey P. Long – O.K. Allen Bridge crossing the Mississippi in Baton Rouge. This is a steel truss bridge over a mile long. It is a both a railroad and highway bridge, the only bridge of this kind owned by the state.  It was brought to fair condition through a rehab project that entailed structural repairs with member strengthening and painting. It was a typical preservation-style project even though it was necessary to use more than the normal preservation funds.

Is TSP2 helping LaDOTD reach your goals? And how?

TSP2 provides a very valuable forum for networking with peers from other states and federal agencies. During the annual South-East Bridge Preservation Partnership (SEBPP) meeting, we get the opportunity share knowledge, success stories and failures. We can learn from states that are ahead in certain areas of bridge preservation. We can also learn their preservation strategies and how they were successful in getting funding increases for their department. TSP2 is definitively a big plus for us.

I would suggest improving the liaison between TSP2 and the Sub-Committee on Maintenance (SCOM), specifically in relation to the flow of research projects. We streamlined this process at SCOM about two years ago (David is Vice Chair on the SCOM Bridge TWG for Asset Management, Performance Measures and Environment. Ed. Note) and now it is TSP2 that is addressing this process. There is the need for fine-tuning research needs between SCOM and TSP2.  There is definitively room for improvement in this aspect of the collaboration.

TSP2 is now sending representatives from its four regions to SCOM. This really helps with creating continuity between SCOM and TSP2.  For example, at SCOM we recently learned from the North-West TSP2 Region about the benefits of bridge washing and how to get through the process with environmental groups.  That would have never happened had the North-West Bridge Preservation Partnership (NWBPP) not sent representatives to SCOM.

In general, the more time SCOM and TSP2 people meet and have discussions the better they will be able to get on the same page.  Flow of information between SCOM and TSP2 is improving, but it could get better.



Bridge Preventive Maintenance Program:


Deck Preservation and Retaining Systems are Key Topics at the Upcoming NEBPP in NJ

Author: Lorella Angelini, Angelini Consulting Services, LLC

In less than two months, on September 11-13, the Northeast Bridge Preservation Partnership (NEBPP) meeting is scheduled to take place in New Brunswick, NJ. The meeting encompasses four sessions: deck preservation, research needs, case studies and retaining systems.

Over 150 bridge preservation practitioners specialized in maintenance and repair of concrete and bridge structures will be gathering in New Brunswick from the States that comprise the North-East region: Connecticut, District of Columbia, Delaware, Massachusetts, Maryland, Maine, New Hampshire, New Jersey, New York, Pennsylvania, Rhode Island, and Vermont. In addition to representatives from the owners, the meeting will also bring together contractors, consulting engineers, academia and manufacturers, who can showcase their innovation in products and services.

As with all TSP2 Bridge Preservation Partnership meetings, time will be dedicated to round tables where participants have the opportunity to exchange information and discuss practices that extends the service life of bridges.

Through the free and open exchange of ideas and information, the NEBPP’s mission is to better serve those who use the northeast transportation system. NEBPP strives to use innovation, new ideas, new products, and the combined experience of participant States to make bridge maintenance procedures and repairs the best that can be provided.

For more information please contact Darlene Lane at 517-432-8220 and email hidden; JavaScript is required



A Conversation with Graham Bettis, Director of Field Operations with TxDOT

Graham at the SEBPP meeting in WV

Graham at the SEBPP meeting in WV

Author: Lorella Angelini, Angelini Consulting Services, LLC

I met Graham Bettis at the recent TSP2 SEBPP meeting in Charleston, WV, where he spoke about bridge preservation experiences at the Texas Department of Transportation (TxDOT) in the events of extreme flooding.

Graham has developed a vast and diverse bridge preservation experience at TxDOT. With 53,875 bridges in its 2016 inventory, this state has the largest number of bridges in the USA. The Texas bridge inventory consists of 35,489 “on-system” bridges, which are located on the state highway system and maintained by TxDOT; and 18,386 “off-system” bridges, which are not part of the state highway system and are under the jurisdiction of the local governments (cities, counties, and municipalities).

Graham is the Director of Field Operations for the Bridge Division at TxDOT. His responsibilities include the bridge inspection program and the management of the geotechnical group, in addition to bridge construction and maintenance. Graham is a member of the TSP2 SEBPP Committee.

What does bridge preservation entail at TxDOT?

Since 2001 a primary focus at TxDOT has been addressing Structurally Deficient (SD) bridges, an effort that was fully supported by our Administration. We have been very successful with this. The number of on-system SD bridges in Texas decreased from 483 in 2006 to 187 in 2016, while the number of off-system SD bridges in Texas decreased from 1,642 in 2006 to 678 in 2016. Now that the number of SD bridges is low, we have a unique opportunity to focus on developing and implementing an overall bridge asset management program.  

It is worth noting that an SD bridge is one with maintenance concerns or one that frequently floods. SD bridges do not pose a safety risk; however, to remain open to vehicular traffic, they are often posted with reduced weight limits that restrict the gross weight of vehicles using the bridges. SD bridges are inspected frequently and are closed to the traveling public if determined to be unsafe.

Could you talk about the bridge asset management program at TxDOT?

In the last two years we established the Bridge Maintenance and Improvement Program (BMIP), which is entirely focused on bridges that are in “fair” condition.

The number of bridges in “good” condition in Texas is increasing, while the number of bridges in “poor” conditions is decreasing, which is what we want. However, the number of “fair” bridges is increasing because we have a number of “good” bridges that are becoming “fair.” So we really want to concentrate on hitting those “fair” bridges that have a condition rating of 5 or 6 and push them back up to “good” so as to maintain their service life in an economically efficient manner.

How has the BMIP evolved over the past years?

The program is still in its infancy. It began three years ago and we have just one engineer to oversee it. In the first couple of years we were focusing on 10-12 bridges per year, mainly large projects. Now we are addressing 70-80 bridges per year, which is in line with BMIP target.

Could you highlight the key elements of the bridge preservation strategy at TxDOT?

As I said before, a key element is to identify those structures where it makes financial sense to address defects early on and get ratings back up to good (condition ratings of 7 or higher – ed. note).

We are also working on a bridge life-cycle cost analysis, in which we compare the cost of repair/rehab versus replacement. While some rehab measures are very cost effective, others are extremely expensive.  We want to have a method that allows us to identify those bridges that can give us another 5 or 10 years of service life before replacing them versus investing in rehabilitation.

If it costs $1M to rehabilitate a bridge today, compared to $1.5 M to replace it 10 years from today, we will likely choose the replacement because the level of quality we get out of new bridge construction is very high. Even if it costs more initially, replacement is an economical solution in the long run because we will get 100 years of service life out of a new bridge.

The goal of the rehabilitation program at TxDOT is to extend the service life of bridges by 25 years, which is one-fourth of the service life extension we get with replacement. In other words, even successful repairs have fairly limited effective life in comparison with new construction.

We are trying to improve all aspects of rehabilitation, from engineering evaluation to plan preparation and actual quality of the work itself. None of these aspects are quite as effective as for new construction. There are a lot of opportunities for improvement in repair and rehabilitation.

What are the challenges in the implementation of the bridge preservation strategy at TxDOT?

The sheer magnitude of the number of bridges in Texas represents the main challenge in the implementation of our long-term goal to reverse the trend of bridges in “fair “condition.  We have to deal with financial constraints and limited resources that do not match such a massive inventory.

A major implementation challenge also entails convincing our own Districts to dedicate some of their resources to cyclical bridge maintenance. We can strive to build bridges that are as maintenance free as possible, but at some point cyclical maintenance is necessary in order to extend the life of a structure. Cyclical maintenance does not cost much and it is really effective keeping small problems from becoming big ones. We know, for example, that if we do not take care of relief joints in approach slabs, the abutments will start pushing on the bridge ends, which is a major problem. Joint repair, clearing drains, cleaning caps’ tops are examples of cyclical maintenance at TxDOT.

With so much focus and resources on maintaining pavements, it is challenging to bring the attention of the Districts to bridges and convince them to think about bridges in the same way as they do about pavements.

Pavement problems are always front and center for Districts, while bridge problems are usually less visible. Since pavements and bridges are part of the overall asset, there should not be a dividing line between them.  

Management of pavements and bridges runs on two parallel yet separate tracks to the point that there are different pavement and bridge maintenance crews. I think that pavement and bridge practitioners should work together on preservation issues.

Is TxDOT involved with off-system bridges?

Yes, we inspect them and we financially support their replacement. If there is a critical finding or a closure is going to happen, we then get involved with the owner–the county, municipality, or city—to determine what needs to be done.

Overall we have far less control of the off-system bridges in comparison with the on-system bridges. We also are not involved with the maintenance of off-system bridges. It is up to the local owners to maintain these bridges.  There is little, if no, maintenance for off-system because of limited resources for a large number of bridges.

Is TSP2 helping reach your goals?

What I like of  TSP2 is that it is getting us all together and giving us an opportunity to talk about things that are working and not working with bridge preservation.

While so much of the focus nationally is on data collection to the point that we are dealing with data overload to some degree, TSP2 is refreshingly down-to-earth since it focuses on the nitty-gritty details of bridge preservation.

In a conference like this (SEBPP ed. note) we sit with consultants, suppliers and contractors exchanging information. There is always something that we can bring home and make use of.

What can TSP2 do to improve its program?

Maybe TSP2 can find ways to keep bridge preservation practitioners connected during the year through webinars and conference calls so as to build on the annual conference. Sharing information through websites and social media is effective, but there is nothing like putting a date in a calendar and attending a meeting, even if it is simply by web connection.

Our TSP2 SEBPP committee core group has already implemented a strong communication process with calls once or twice a month. We should consider improving communication beyond our core group by increasing the amount of time that bridge practitioners from different states talk with each other and exchange information.



Report on Texas bridges:


Bridge Facts:


A conversation with Keith Kesner about the new ACI 562-16 Concrete Repair Code

Keith Kesner

Author: Lorella Angelini, Angelini Consulting Services, LLC

I met Keith Kesner at a monthly educational meeting organized by the Minnesota Concrete Council (MCC) in St. Paul, MN, when he gave a very informative presentation about the American Concrete Institute (ACI) 562: “Code Requirements for Assessment, Repair, and Rehabilitation of Existing Concrete Structures and Commentary”. I then contacted Keith in order to know more about the new Code and its potential use for bridge preservation.

Keith, the chair of the ACI 562 Committee, is a registered Professional Engineer in several States. He has over 20 years of experience as a structural engineer and he has written over 100 publications on a variety of structural engineering topics. He works as a Project Manager with CVM Professional in King of Prussia, PA, a Consulting Engineering firm that specializes in the evaluation and rehabilitation of existing structures.

Founded in 1904 and headquartered in Farmington Hills, MI, ACI is a leading authority and worldwide resource for the development and distribution of standards, technical resources, educational training and certification programs related to concrete design and construction. ACI has over 95 chapters, 110 student chapters, and nearly 20,000 members spanning over 120 countries.

Could you speak of the goals of ACI and introduce the ACI 562 Concrete Repair Code that you chair?

ACI is an international organization with the objective of developing and distributing knowledge on concrete design and construction. Some of the key goals of the Institute include the development and maintenance of standards and consensus documents for the design, construction and repair of concrete structures.

People are probably most familiar with ACI 318 Building Code, which is the US Standard Code for reinforced concrete construction. ACI 318 is also very heavily used internationally.  ACI has produced a wide variety of other documents, such as specifications and procedures for concrete construction in different types of environment, from hot to cold weather, development and standards for the use of Fiber Reinforced Polymer (FRP) materials and the repair of concrete structures.

ACI has much wider reach than what people are most familiar with, which is ACI 318.  It is a very large organization that covers all aspects of concrete construction.

Who are the professionals that are part of the ACI membership? Does ACI mainly gather Consulting Engineers?

Consulting Engineers are a prominent presence in ACI, but other groups of professionals are also strongly represented in the Institute. These groups include cement producers, concrete producers, manufacturers of construction products, contractors focusing on concrete construction and repair, and academics involved with research on the design and construction of reinforced concrete structures. ACI has a very broad-based membership that touches all aspects of the concrete industry.

What are the key elements of the new ACI 562-16 Code?

The ACI 562 Code was developed to be a parallel document/Code to ACI 318. Whereas ACI 318 deals with new building construction, ACI 562 was developed specifically for the repair of existing concrete buildings. It was also designed to work with the International Existing Building Code (IEBC).

ACI 562 was designed to be a performance-based code with prescriptive requirements when required. It basically provides design professionals with code requirements for the assessment of existing concrete structures and then, depending upon the results of the assessment, procedures for the design of appropriate strategies for the repair, including durability requirements.  The code also calls for future maintenance and monitoring requirements to be documented by the licensed design professional for the owner.  However, ACI 562 cannot mandate that actual maintenance be performed.  

Is ACI 562 a new Code?

Yes, ACI 562 is a completely new Code. The first edition was published in 2013. The current ACI 562-16 edition, which was published last year, is an update of the 2013 version. So we are currently on the second version of the Code.

Is the 2016 update significant?

Yes, the Code was updated significantly from 2013.  We made a lot of changes to the terminology to make it consistent with documents published by other standard developing organizations. We added code requirements and commentary on these requirements to better define the level of repairs that may be required on existing structures. We worked on better integrating the Code with IEBC requirements.  We also spent a lot of time working on requirements for the bond of the repair material to the existing structure.

A major update entailed the introduction of the concept of “demand to capacity ratio” in order to better delineate the extent of the repair that may be required in a building.  As an example, let’s suppose that we have a beam with a load of 100 kips, as specified by the building Code. If after evaluation we find out that the capacity of the beam is, let’s say, 80 kips, we can calculate the demand to capacity ratio by dividing 100 by 80 = 1.25.  Being the ratio  greater than 1, the beam requires strengthening and the repair must be designed in order to provide the amount of strengthening that will bring the ratio back to or lower than 1.00.

In summary, the “demand to capacity ratio” represents a measure of how deficient the structural element is and therefore it is a measure of the amount of strengthening that needs to be added to the structural element in order to satisfy Code requirements.  

Does the Code include guidelines on how to evaluate the capacity of a concrete structural element that has deteriorated over time?

Yes, this information is contained in Chapter 6 of ACI 562, which deals with how to do the evaluation of a deteriorated structural concrete element. There are a lot of documents that have been published on the evaluation of existing concrete structures, which are referenced in the commentary to the Code. Design professionals using the Code can look up to these documents and can get additional information on how to evaluate the current capacity of existing concrete structures.

Where did the need for the new ACI 562 Code stem from?

The need was really recognized by people involved with the concrete repair industry, who realized that repairs on existing structures were not performing adequately. A thorough investigation was carried out by a couple of different groups: the US Army Corps of Engineers and the Building Research Establishment (BRE) in the UK. Both reports (see linkage, ed.) concluded that repairs of concrete structures were failing at a high rate. Improved repair techniques providing better performance of repairs were needed in order to avoid repair of previously repaired structures, which is obviously a waste of money.  

By creating a standard for the repair of building structures we responded to a recognized need in the concrete repair industry and made a significant progress in the direction of improving the performance of repaired concrete structures. In addition, by introducing the “demand to capacity ratio” concept, we provided a tool for achieving a consistent level of reliability for repaired concrete structures.

It is likely that what you said about repairing repaired structures also applies to the DOT experience with concrete repair. In fact DOTs have started focusing on preservation practices based on cyclical and preventative maintenance, which do not require major concrete repair applications.  How could ACI 562 be of help to bridge preservation practitioners?

The ACI 562 Code was specifically developed for building structures. A direct translation of many of its parts to bridges would not work since loads and resistance factors are different in bridges compared to buildings. However, the performance-based concepts that were used in the development of the ACI 562 Code can be appropriate for bridge structures.

Information included in Chapter 8 – Durability could be of particular benefit to bridge preservation practitioners. When we talk about durability of a repaired concrete structure we must consider the durability of the original structure, the durability of the repair, and the interaction between the repaired area and the original structure. This holistic approach to concrete repair underscores the fact that it is not sufficient to just have a durable repair or a durable portion of the original structure but it is the whole system that needs to work together.

A lot of the problems with durability of repairs relate to the addition of new materials, that have different electrochemical properties and stress-strain response than the existing materials. We must predict how these new repair materials are going to interact and respond when they are applied to the original structure. The comprehensive concrete repair concept will likely fit with current practices adopted within bridge preservation as part of an asset management program.

Would ACI consider the possibility to collaborate with TSP2 for the development of a performance-based specification for concrete repair?

Yes, absolutely. I would also suggest looking into ACI 365 Committee – Service Life Prediction, which is working on developing service life prediction standards and procedures for concrete structures. Some of the work that has been already done by the 365 Committee may be of great interest to engineers and practitioners who deal with bridge preservation.  

ACI Committee 563 is also in the process of developing specifications for repair of existing concrete structures.  The concrete repair specifications should be completed in late 2017 or early 2018.  



ACI Vision 2020—Repair/Protection Council


The Condition of Corps of Engineers Civil Works Concrete Structures, Technical Report REMR-CS-2, 1985, 133 pp.

Building Research Establishment (BRE): Thematic Network on Performance-based Rehabilitation of Reinforced Concrete Structures      


ACI 562 from Structure Magazine