There’s good news and bad news when it comes to our nation’s bridge infrastructure. First, there are over 90,000 structurally deficient bridges in the United States, according to the Federal Highway Administration (FHWA)—that’s the bad news.

The good news is that, according to the FHWA Office of Bridge Technology, that number is coming down. Matt Jeanneret, vice president of communications with the American Road and Transportation Builders Association (ARTBA), explains, "Over the last six years, more than 14,000 bridges that were on this list have been either rehabilitated or replaced. The investments in TEA-21 paid some dividends. But, there is obviously much bridge repair work that remains."

Most recently, SAFETEA-LU authorized $21.6 billion for the bridge rehabilitation, a continued recognition by Congress of the need to repair and maintain the nation’s bridges.
Jeanneret continues, "This is good news even though there is tremendous flexibility in how states plan to use some of their money. There is no guarantee that all of this money will actually be spent on bridge improvements. It will likely vary from state to state."

Fix it Now – or Later?
There are some experts and academics who believe the industry should rethink the way it decides how to spend this bridge money.

"Owners, and in particular, their ‘traditional’ bridge engineers, continue to rely on visual inspection to determine bridge viability. That must change," says Jim Cooper, formerly the director of bridge technology at the FHWA and now an independent bridge technology consultant. "With so many bridges deemed structurally deficient and limited funding, determining which bridges need immediate rehabilitation or replacement should not be left to a simple visual inspection—and yet that is the common practice."

Cooper and other bridge experts point to new technologies—both materials- and computer-based solutions that can determine which problems need immediate correcting and more importantly, which ones can safely wait.

These include common wireless and communication technologies, coupled with the latest sensor technologies. Put together, these tools can be combined to help a bridge engineer quantitatively identify where to use precious financial resources to get the best return on the public’s investment. "Believe it or not, that is a very difficult, foreign concept for the bridge engineer to grasp and implement," Cooper adds. "One reason is that the bridge engineer feels he has to put his budget into steel and concrete rather than accepting and implementing newer technologies that would actually improve their return on investment.

Vistasp Karbhari, professor of Structural Engineering at the University of California, San Diego, agrees, adding, "We should use structural health monitoring techniques commonly on new bridges, as well as on older bridges, especially those of critical lifeline routes, because the technology is so affordable. We even have the new composite bridge near the Salton Sea in Southern California instrumented with sensors so that transportation engineers can monitor the structure 24-hours a day through a wireless network."

However, experts caution that it’s not just about gathering more data. "It’s more what we do with the data," emphasizes Karbhari. "Too often engineers put hundreds of sensors on structures and get lots of data. Unfortunately, if they have not set up procedures to rapidly evaluate the data to assess capacity and service life, the data has no value."

The key is in putting together systems that use a minimum number of sensors placed at critical locations and incorporating data from these with response models and damage detection algorithms that can pinpoint changes in behavior and damage.

Intelligently placed, sensors can help bridge owners and operators make smart decisions about a bridge based on real data such as traffic, risk and remaining capacity—rather than more traditional visual inspection methods.

"Just as importantly," says Dr. Chung C. Fu at the University of Maryland, Bridge Engineering & Technology (BEST) Center, "health monitoring systems can be used as a management tool for a regional transportation infrastructure system especially in the case of emergencies."

Build it Faster
Others believe that it is rapid bridge construction techniques that will significantly improve speed and reduce costs. There are a number of outstanding examples in the industry including the US 20 Iowa River Bridge project completed in 2003 by the Iowa DOT and HNTB. This project used an innovative construction technique called incremental launching, first developed in Europe, to build a four-lane steel I-girder bridge over the Iowa River. In this process, the steel girders are constructed on the bluff overlooking the river and then rolled across the tops of the piers into their final position. Popular in Europe, Japan and other countries, this was the first time this technique had been used in the United States and while it was used primarily for environmental protection, it is also a sound technique for building with limited interruptions to the surrounding area. The method worked so well that the contractor for the Clifford Hollow steel girder bridge in Moorefield, W.V., redesigned his construction methodology to use this technique, realizing similar benefits.

Texas relied on similar prefabrication methods to build the I-35 and Highway6/Loop 340. Each of the four bridges was built off-site and will be moved into place using a pair of 200 ton cranes in September 2005. It's the first time TxDOT has ever built a bridge like this and many believe the success of this project will revolutionize bridge construction in Texas.

Claude Nappier, Division Bridge Engineer, Virginia, FHWA, says, "We really need contractors to accelerate construction, to do what they can to maximize the use of prefabricated elements like we see in Europe and Japan. It’s these kinds of techniques that will help us make the most use of every dollar available in transportation legislation like SAFTEA-LU."

Clearly there’s an enormous amount of work left to be done and some clever minds at work to find the right solutions that range from composites and prefabricated components to corrosion prevention and non-slip surfaces. In the following executive roundtable, we asked industry experts, professional organizations and service providers to offer additional insight into the industry trends, issues and overall state of bridge rehabilitation, renovation and replacement.

Photo Gallery

Coton Bridge, in Loudoun County, VA, is one of CON/SPAN® Bridge System’s, a CONTECH company, largest structures to date with 189 precast arch units that resemble historical bridges in the area.
Corman Construction and its partners rely on innovation to speed delivery of their Woodrow Wilson Bridge Projects.
Made completely of plastic, carbon and glass the Kings Stormwater Channel Bridge in California is so lightweight two men can do what normally requires a crane.	Duck Brook Bridge at Acadia National Park in Bar Harbor, ME, constructed by VHB uses modern materials and membrane waterproofing to appear look 100 years old—yet able to last another 100 years
As a member of the DMJM Harris/Sverdrup/Gerwick joint venture, DMJM Harris led a complete seismic analysis and retrofit design of the approach structures and the trestle spans for the Richmond-San Rafael Bridge in Contra County, CA.

Executive Roundtables

Patrick Jones Executive Director, International Bridge, Tunnel and Turnpike Association (IBTTA)

VS: How will SAFTEA-LU legislation impact the IBTTA community?

PJ: While SAFTEA-LU hasn’t removed all barriers to the tolling of federal aid highways, it has significantly increased the options of state and local transportation officials to address both declining revenues and growing traffic congestion through the use of tolls and pricing mechanisms.

The SAFTEA-LU legislation continues the Interstate toll conversion demonstration from TEA-21 which allows up to three states to convert existing Interstate roadways to tolled roads as part of a major reconstruction. It takes time to build local support for such projects and we understand that there are outstanding proposals right now to use all three slots.

The new law also extends the existing value pricing program to allow projects in up to 15 states to explore ways to manage congested traffic corridors through the application of pricing mechanisms and establishes a new Express Lanes demonstration program to allow the conversion of existing High Occupancy Vehicle (HOV) lanes to High Occupancy Toll (HOT) lanes.

This legislation includes a new demonstration program that allows the construction of up to three new Interstate tollway segments. This provision specifically invites interstate compacts to participate in the demonstrations.

With the increasing movement at the state level to create new toll authorities, expand the missions of existing authorities, or to create toll divisions inside State DOTs, we expect to see a noticeable acceleration in tolling and road pricing in the coming years.

Claude Napier Division Bridge Engineer, Virginia, FHWA

VS: What does the FHWA need from today’s contractors?

CN: We need contractors to accelerate construction techniques. Virginia has approximately 13,000 bridges designated in the national bridge infrastructure program. The DOT is in the midst of a proactive maintenance, rehabilitation and reconstruction program to correct many of these that are designated structurally deficient or functionally obsolete. This can’t get done without their help.

One of the techniques we’d like to see more of is the use of prefabricated elements. Just this past year, I observed several projects where European contractors successfully built entire four-span bridges for a new roadway beside existing railroad lines. Once complete, the project team shut down the railroad lines for several days, removed the railroad tracks, excavated out the roadway prism and literally moved the new structures into place and began operation of the railroad lines. That’s the kind of rapid replacement that saves time, money and enormous public inconvenience.

VS: What’s the most exciting trend in bridge construction in your area?

CN: Without a doubt, it’s the future of performance-based specifications programs. I’ve been involved with several of these projects in recent months with tremendous results. On one of the first, we let the bridge contractor and the ready-mix subcontractor design the high performance concrete for the bridge decks of the NB structure for the Southwest Memorial Bridge (Route 11 over New River at Radford, VA). For the pilot project, the permeability and strength requirements were provided; they selected the material and the processing techniques. In this case, the contractors used a unique combination of fly ash and slag in their concrete mix design that provided excellent quality high- performance concrete with excellent workability and, when tested, very low permeability values.

We like to see contractors willing to push the boundaries to get things done faster and improve quality. I’ve been involved with innovative projects in the past with both steel and concrete contractors where given the opportunities. These guys present some great ideas and offer valuable input and new, innovative construction techniques. We expect to see more of that as the performance-based specifications program expands throughout Virginia’s nine districts.

Dr. Chung C. Fu University of Maryland, Bridge Engineering & Technology (BEST) Center

VS: Is the trend to build new bridges with steel or concrete?

CF: Both have advanced greatly. In fact, all major federally funded bridge projects require both steel and concrete designs. The same is true for the contractor bidding to build a new bridge. That way the DOT ensures they have the best solution for the specific project.

New materials such as high-performance steel, high-performance concrete and, more recently, fiber reinforced polymers (FRP) provide even better solutions. These new materials are easier to put together, last longer and are more resistant to the environment.

VS: What’s the advantage of a composite (FRP) bridge?

CF: It’s all about life cycle costs in our industry. For instance, a concrete deck must be replaced every 10-15 years and is susceptible to corrosion from the internal rebar. A composite deck has a lifespan of more than 75 years with little or no maintenance. That’s the kind of longevity that we must strive to achieve—whether it’s on our roadways or bridges.

VS: What technology is available to support the industry?

CF: Bridges are vital to the national economy. Without proper management of this critically important asset, we will not meet future “structural” and “functional” needs. Asset management provides a framework for identifying the investment needs to operate and manage these facilities systematically and cost-effectively. We must remember that asset management is so important and it requires the combined knowledge of engineering, business management, economics and the latest computer-aided technology.

Delbert F. Boring, P.E. VP, Construction Market Development, American Iron and Steel Institute (AISI)

VS: What impact did the recent SAFETEA-LU bill have on AISI members?

DB: This bill designates $20.4 million to high-performing steel research. A portion of this funding will be used for research into High-Performance Steel (HPS) for bridges (HPS 50W, HPS 70W and HPS 100W), guaranteeing continued research in advanced design and materials that emphasize the extension of bridge life, increased safety and reduced maintenance.

The bill’s inclusion of funding for high-performing steel research is indicative of growing awareness at the federal and state levels of the benefits that this new material offers to meet the nation’s transportation infrastructure challenges. Of the United States’ 594,000 bridges, roughly 25%—151,000—are structurally deficient or functionally obsolete.

VS: Is HPS commonly used on bridges today?

DB: Since 1997, an estimated 200 HPS bridges have been opened to service in 43 states. While that’s still a small percentage, it’s been proven that HPS provides overall weight and cost savings over conventional steels through an optimized balance of strength, weldability, toughness, ductility and corrosion resistance, translating into longer life for bridge structures.
Innovative, dependable high-performance steels are the design solution for rebuilding America’s transportation infrastructure.

Peter Vanderzee President and CEO LifeSpan Technologies

VS: What’s wrong with bridge management today?

PV: The key to managing this system is to understand which bridges truly need attention and which can wait—it’s simply better asset assessment.

What passed for “knowing,” or asset assessment, in the 20th century was visual inspection of the structural asset, per FHWA’s National Bridge Inspection Standards (NBIS). That protocol, which returns subjective information, is not good enough for our most difficult bridge challenges. We now have affordable structural monitoring technology that allows owners to clearly understand what’s happening in existing steel and concrete structures. We need to use it on key structures and define a clear plan of attack from there.

VS: How does this technology work?

PV: Basically these new sensors and systems “automate” the capture of data from structures using wireless modems, network operations centers and efficient Internet presentation of captured information. The technology is very useful for bridges that have known defects and suspect load carrying capacity to help optimize life cycle cost, reduce risks and develop long-term capital expenditure plans.

VS: What are the implementation costs?

PV: A monitoring system for a major structural asset should typically cost less than two years’ interest on the funds required for its replacement. But, it’s really only needed on those structures that are categorized as “structurally deficient,” and perhaps only a subset of those.
However, before investing in a long-term structural monitoring program, owners must develop and communicate clearly defined objectives to service providers about their overall asset management plan and how they intend to manage an inventory of deficient structures with insufficient funding.

Vistasp Karbhari Professor of Structural Engineering University of California, San Diego

VS: Why aren’t composites for bridge construction more widely accepted?

VK: They are still relatively new for this industry and there is a lack of standards. Even though composites have been used in the industry since the early 1990s, we still don’t have codes that define the use of composites on major structures. There are some specifications within DOTs, and the Civil Engineering Research Foundation also introduced some guidelines with regard to seismic retrofit, rehabilitation, and bridge decks.

But we need an AASHTO code.

VS: Where are composites providing the most advantage?

VK: At present, certainly in rehabilitation and seismic retrofit. The use of composite decks is also increasing in specific areas because they are efficient to place, light and often the best way to extend a bridge’s service life. In New York and Oregon, for example, engineers have replaced the decks on old truss bridges with fiber reinforced composite decks to increase durability and increase load carrying capacity.

VS: How do you see the future of composite bridges evolving?

VK: Right now very few of the bridges in the country are made of composites or are rehabilitated using composite elements. That will grow a lot in the next few years because the life cycle cost, durability and weight benefit are too much to ignore.

The construction of new all composite bridge structures will take longer. The industry is just not that comfortable yet, and we as researchers need to do a better job of education so that contractors feel more at ease with the reliability, life-cycle affordability and ease of construction with these new materials.

Bill Cox President Corman Construction

VS: How are you meeting increasing industry demand?

BC: No doubt, today’s major transportation issues typically associated with traffic congestion have changed the way we provide service to our customers. These jobs are more technically challenging and are often larger scale projects that require a more innovative approach by the contractor than might have been expected historically. We believe that this is where our people excel. The goal is clearly to get jobs done more efficiently and at a lower cost.

Our industry must also be more aggressive in working with owners to improve job sequencing to better support community needs, develop and deliver new high-performance materials that offer strength and longevity, and most importantly, shorten construction time. We have been very successful on several recent projects by applying these concepts.

VS: How can you best provide these services?

BC: We’ve been successful in responding to these demands through both traditional and design-build delivery mechanisms. The design-build method clearly gives us the opportunity to use our engineering skills and shared experiences to recommend some innovative ideas, because we’re an integral part of the design team during the design and on the job, during construction. We can, in effect, build better projects.

VS: Are you talking about applications of new materials or processes?

BC: Both, actually. Sometimes it’s just a better use of existing materials and processes. For instance, on a recent cable-stayed bridge in Virginia, when it came time to pour the concrete for the bridge masts, it was readily apparent that the space between the rebar was too tight to pour a traditional mix concrete. Instead, we recommended self-consolidating concrete, which provided the required strengths while flowing around the rebar. This is a product that we expect to see used more frequently as owners gain confidence in its strength and flexibility.

However, new materials are critically important to current and future bridge construction. The new high-performance concrete and steel materials offer tremendous advantages over more conventional materials in terms of strength, longevity and life-cycle costs. We’re using high-performance concrete on the Woodrow Wilson Bridge Deck in Virginia. The 17,500 cu yd of high-performance concrete used on the project will provide a stronger, more durable and corrosion-resistant deck.

Each of these examples reflects the demands of this new era in construction. Our job is to engineer, not just build, better bridges.

Chris Gagnon Senior Vice President, Ammann & Whitney

VS: What are the challenges of rehabilitating suspension cable systems?

CG: While existing FHWA standards provide general guidelines, each bridge is unique and must be approached accordingly. For example, the location and extent of corrosion may vary depending on original bridge design, construction practices, maintenance history and environmental conditions. Inspection teams must know what to look for and fully understand observed conditions, requiring specialized skills developed only from hands-on experience.
Key facets of suspension system rehabilitation include: determining the level of corrosion and its effect on structural elements, designing repairs to corrosion damaged elements and developing future maintenance programs.

VS: Are there special skills required to do this right?

CG: Absolutely. Cable inspection entails unwrapping portions of the cables and driving wedges to spread the wires for visual inspections, mapping corrosion levels and broken or cracked wires, testing wire samples for physical properties, and evaluating the effect any damage might have on the cable strength. Global bridge analysis is often performed to gauge demand versus structural capacity. We have performed more than 20 cable investigations and rehabilitation designs including complete rewrapping of cables on ten bridges.

Suspender rope testing and replacement requires similar expertise to determine if temporary support is required, design appropriate measures, develop testing protocols and interpret the results. The replacement of bridge suspenders is typically complicated by the need to keep the bridge operating during the construction. The design therefore requires defining specific equipment and procedures to transfer the suspended loads from the old to the new suspenders.

VS: What new technologies are emerging in this market?

CG: One of the most prominent is the dehumidification and dry-air injection for corrosion prevention. We completed designs for anchorage dehumidification for major suspension bridges and studies and preliminary designs for dehumidification for main cables of three U.S. bridges.

Non-destructive testing techniques are also progressing, which allow us to better determine existing conditions in a more cost-efficient manner.

Our specialized knowledge continues to grow through corrosion studies—from the Akashi-Kaikyo Bridge in Japan, where we provided analysis of corrosion effects in a worldwide survey of bridge suspension systems, to evaluating and designing corrosion protection systems for the main cables of numerous suspension bridges such as New York’s Throgs Neck Bridge.
Our clients depend on us to define causes and develop solutions to the most challenging suspension bridge projects in the world—and we’re doing it.

Chuck Fortener President, Contech Bridge

VS: Has your business changed to meet industry demand?

CF: Today, public and private clients demand cost-effective bridge solutions—and they want more than one choice. To meet this need, we’ve become a multi-faceted resource for state DOTs, municipalities, consulting engineers and private developers looking to build new or rehabilitate existing short span bridges (those 150 ft and below). We’ve done this through strategic acquisitions that have expanded our capabilities to provide a variety of bridge solutions.

We currently provide precast concrete arch bridges, steel truss bridges and pre-engineered steel plate bridge solutions in a wide variety of shapes, sizes and general appearance.

VS: What is the number one requirement from clients?

CF: Speed. As solution providers, we must find ways to minimize road closures and provide owners quick access to newly developed property. We’ve focused on two effective ways to do this. Prefabrication allows bridges to be designed and manufactured off site in a controlled factory environment and delivered in as few pieces as possible to make installation quick and simple. Our bridge portfolio consists of products that can clear-span most small streams. By staying out of the water, and off the banks, we can minimize the time delay associated with obtaining required permits.

Traditional methods of cast-in-place are simply too slow. Our clients don’t have weeks to set concrete forms, pour concrete and then wait for it cure. With prefabricated bridge structures that meet environmental needs, we can be in and out of a site within a day or two.

As an example, we recently installed a concrete arch system for a new residential development in Florida. The bridge system, which included three 36-ft spans, was delivered to the site in multiple precast pieces and then lifted by crane onto a foundation. This entire process was completed in two days.

VS: Are new materials part of your existing or future bridge systems?

CF: We continually research new materials and processes in concrete, steel and even composites. There are a few applications that show promise, but it’s really hard to beat the availability and cost-effectiveness of standard concrete and steel. Most of these new material options are expensive compared to traditional materials—and really don’t offer any extraordinary advantages, yet.

But, we’re always looking for the materials and processes that will give our clients a quality bridge solution that meets time and cost constraints, strength, environmental considerations and lifecycle management.

Jim Weinstein Senior Vice President, DMJM+Harris

VS: Has the increasing need for infrastructure improvement changed bridge design?

JW: The enduring challenge in delivering new bridges has been and continues to be the need to make them more durable. The increased focus by clients on asset management demands that designers look to stronger, lighter materials that meet the durability challenge while maintaining safety all at the lowest possible cost.

Yet, as an outgrowth of the context-sensitive evolution, there is a growing demand, at the community level, for signature creations that reflect and represent the character of the communities in which they are being built and, clients are willing to spend a little extra money to get it.

VS: What impact will SAFTEA-LU have on these demands?

JW: The new bill will help our clients begin to address the huge backlog of bridge rehabilitation and new bridge needs. However, needs will always exceed the financial resources to address those needs. DMJM+Harris recognizes this and specializes in finding solutions that fit within the constraints of our clients’ budgets.

To accomplish this, our design engineers must continue to stay on top of advancements both in design and new materials that will help our clients achieve their goals not only in terms of construction cost but, perhaps even more importantly, in the management of the asset once it is put into service.

VS: Do you see procurement methods changing to speed delivery?

JW: Yes. There is increasing emphasis on design/construct and public private partnerships. As a company we have responded and we now have specialty practices in both design/construct and public/private partnerships. And, at any given time, we’re engaged in a range of both.
Each of these methods can help stretch the value of the existing transportation dollar by expediting project delivery. I believe we’ll see more of both because the industry is proving that they work well and FHWA continues to promote both.

In the end, however, it’s not so much the method of procurement as it is the effectiveness of the solution that we deliver. When it comes to bridges, not only must we provide a structurally sound design that meets the test of time, we also must offer effective ways to put that project in place with consideration for the community, the environment, and the mobility of the area in which it is being undertaken.

Our job is to develop solutions that solve our clients’ problems.

Phil Rahrig Executive Director, American Galvanizers Assn.

VS: Can galvanized steel help bridge owners save money?

PR: Absolutely—and many owners don’t take advantage of it. The cost of galvanizing has gone down in real dollars by approximately 50% in the last 20 years and is now very price-competitive with most two- and three-coat painting systems. In terms of life-cycle maintenance costs, galvanized bridge girders, columns, and railings in all but the harshest environments will last upwards of 60 to 75 years without maintenance, where a painted bridge requires repainting every 10-15 years to prevent corrosion.

VS: Is there a limit to the bridge size when galvanizing?

PR: Not so much anymore. Thanks to advancements in the industry over the last 5-7 years, today’s state-of-the-art galvanizing operations can accommodate very large and long bridge members without problem. There are many galvanizing operations in U.S. and Canada that can accommodate 80- 120-ft-long girders.

VS: Who’s using galvanized steel in the industry?

PR: Bridge owners in Europe galvanize everything they can because of the long-range cost savings. There are galvanized reinforcing decks in Bermuda that haven’t required maintenance in 50 years and Quebec is using galvanized rebar for all of their new bridge decks.

The market for galvanizing continues to grow in the U.S. Pennsylvania and Ohio, for instance, build galvanized truss and short-span bridges whenever and wherever they can. Virginia, Florida, and New York are using galvanized reinforcing steel, also increasingly popular over more conventional black steel or epoxy coated steel, because of longer life.

But the private sector is where the jump is. These owners are looking at improved asset management, and life-cycle costs, to make infrastructure last. Galvanized steel offers them a long-term, affordable solution.

Ron Askin Western Regional Manager, Godwin Pumps

VS: How can pumps make or break a bridge project?

RA: The magnitude of dewatering can come as a surprise—typically, there’s more water infiltration than a contractor has been told to expect. Our job is to keep them dry.

This is critical in terms of scheduling. On a large-scale bridge construction project, such as California’s Oakland Bay Bridge, a shutdown can run in the hundreds of thousands of dollars.

VS: What can Godwin Pumps provide that’s unique?

RA: Bridge contractors are very service oriented. They need and in fact demand suppliers who can respond quickly with product, parts, and service.

Godwin Pumps has a branch or distributor in major cities worldwide with local parts and service. We also have extensive experience and a reputation for producing the most reliable pumps in the world. Our people work closely with the contractor during the bidding process to provide budget numbers and pump availability assurances, and then on-site through design and installation. Often, a job gets under way and the parameters change—and we’re there to help.

VS: Is pump technology today different than 20 years ago?

RA: The concept of a centrifugal pump has not changed—only how it’s applied, as well as the added features and benefits. For instance, our HL160M single stage pump used on the Tacoma bridge project is the only pump of its kind to achieve discharge heads to 600 ft of head, handle solids, self prime and run dry. We make sure contractors have the right equipment to fit their unique needs anytime, anywhere.

Chris Baker National Director of Structural Engineering, VHB

VS: How is the bridge building industry evolving?

CB: While bridge construction and rehabilitation are still the realm of DOTs, municipalities and counties are being increasingly challenged to become bridge builders in the 21st century. As state and federal governments continue to pass funds down to these local agencies, it gives them considerably more freedom to build what they want and like. This is often very different than the traditional DOT-type bridge construction.

In all cases, federal, state or local, the real challenge is limited funding. Even with SAFTEA-LU, there’s not enough funding to correct all the structurally deficient bridges.

VS: How do new materials influence bridge design?

CB: The FHWA has asked the industry to design for a 75-year lifespan. That requires good materials, such as high-performance concrete and steel. I can remember when 50 ksi was considered high-performance steel. Now 70 ksi is the norm, and new materials are 100 ksi. Each of these improvements offers longevity, durability, weight savings and strength.

VS: What’s driving the cost of bridge construction?

CB: It’s the parts that go beyond the structural. For instance, five years ago, no one in the U.S. thought we’d be asked to understand how someone might place a bomb on a bridge deck or supporting pier. There’s also the increased demand for reversible movement to improve evacuation or emergency access. These are questions that we, as an industry, must be able to address to support our homeland security concerns. We are working hard to adapt to this new reality. Recognizing the importance of this to our clients, in 2004 we acquired Fortress, Inc., a national security firm specializing in transportation security and emergency preparedness programs.

Additionally, the environmental permitting process is becoming more thorough and involved.
And finally, there’s the need for speed. People have less tolerance for detours and road closures, so we must find ways to build bridges faster. All this adds up to cost. Not long ago, you could design a bridge at 10% of construction costs. In many cases, that number has risen to 25% or more. Our goal is to bring this down through better construction processes, an increased use of prefabricated components, speedier delivery methods and much more.
It comes down to being aware of where your industry and your clients are, and where they are headed, and making that new reality part of the way you think and work.

Bridge engineering today is much more than a structural problem—it’s a social, environmental and national-security puzzle. At VHB, we welcome the challenge.

Godwin Expands Line of Electric Submersible Pumps

Sub-Prime electric submersible pumps from Godwin Pumps are now available in a full range of dewatering, trash, sludge and slim-line models. The electric submersible pumps are available in 1/2 to 90 horsepower with flows to 5,000 gallons per minute, heads to 375 ft and solids handling to 3.2 in. in diameter. Ideal for dewatering applications, the pumps recently have been used on the construction site of California’s new Oakland Bay Bridge for cofferdam dewatering. These pumps also are used in mining, quarrying, industry and other construction-related projects. For more information, email sales@godwinpumps.com or call the Bridgeport, NJ-based home office at 856-467-3636.

Rolled Beam Bridges Meet Tight Schedule

When the Missouri Dept. of Transportation embarked on a plan to rehabilitate approximately 6.5 miles of Route 350 in Kansas City, the team chose rolled steel beams from Nucor-Yamato Steel Co. for replacement of twin bridges over 63rd Street.

"We chose steel beams because we could use smaller girders," says Dan M. Smith, P.E., structural projects manager for MoDOT. Achieving maximum vertical clearance for the lowest cost was a priority for the design team. "If we had used concrete girders, we would have had to raise the grade on Route 350, and that would raise the overall cost of the project," says Smith.

Carrying an average of 17,500 vehicles per day, the section of Route 350 addressed in the project is a vital transportation link within the Kansas City area. APAC-Kansas Inc. was awarded a subcontract by the Superior-Bowen Asphalt Co. for the demolition and replacement of the two bridges. The replacement structures consist of twin 264-ft 4-span rolled beam bridges. The project used a total of 469,920 lb of structural steel.

High traffic levels and the route’s importance to the area forced a tight schedule of four months from demolition to completion, according to Scott Gammon, P.E., area manager of structures for APAC-Kansas. At any given time, his firm has multiple rolled-beam bridges under construction and the crews are accustomed to working fast. Even so, the four-month turnaround was a challenge. o

Protecting Bridges
by John Tiernan

If life were fair, cars would only break down in full daylight in mild weather, and all bridges would be built of weathering steel that never needed painting. But experience proves that automobiles mostly balk in the coldest or wettest weather and often in the dark, and except for the driest locations—maybe over inland canyons—most steel bridges will eventually need protective coating.

Given a price premium approximating 10 to 15%, weathering steel is probably best used in not-too-wet climates, though even in wet areas it can still have benefits, as determined by comparing it with carbon steel.

Regardless of where it’s to be placed, it’s a given that carbon steel will have to be protected with a primer and a topcoat. According to the Society for Protective Coatings, ideally the primer is a zinc-rich inorganic ethyl silicate, especially when shop coated. The next choice is a zinc-rich epoxy. Typically, the topcoat is a one-coat epoxy or aliphatic polyurethane, or a choice of two coats of moisture-cured polyurethane or one coat of two-component aliphatic polyurethane.
If a weathering steel bridge is pitting due to high salt or humidity, then it will require the same steps as a carbon steel bridge for which the paint has deteriorated—namely scouring, priming, and topcoating. But at this stage, the benefit that offsets weathering steel’s higher initial cost is that blasting rates are 20-40% lower than on carbon steel, and at $7-$12 per sq ft, that can count for a lot.

So, as most bridges will at some point need protective coatings, the following chart lays out where some of the coatings companies see their products’ best applications.

The Fast Pace of Bridge Design Innovation
Joseph Showers, P.E.
Chief Bridge Engineer, CH2M Hill

Rehabilitating or replacing bridges often requires project teams to navigate a series of complex site, schedule and project constraints as well as addressing regulatory requirements and dealing with funding constraints.

In response, engineers have met these challenges through innovative approaches and technology applications, including alternative project delivery and the use of higher-performance construction materials to reduce maintenance costs. On our recent designs of long-span concrete bridges and urban freeway system interchanges, we have experienced the pride and satisfaction that comes with achieving truly community-sensitive solutions. Our design-build projects also continue to demonstrate the creative potential of genuinely collaborative relationships between designers and constructors that produce innovations in design, materials and methods, while saving clients time and money.

We have an increasingly wider range of construction and material technologies to choose from when designing a bridge project and we expect a continued increase in the pace of innovation. We can look forward to the prospect of bridges constructed more rapidly and safely with less impact on the traveling public. New materials technology developments offer the prospect of increased durability and reduced bridge life cycle costs as well.

Because environmental quality continues to be an important value to communities, we see very innovative and exciting design schemes developing from the collaborative participation of architects and engineers in the bridge design team as they create context sensitive solutions. 

Virginia DOT-Sponsored Project Controls System
Keeps Bridge Projects On the High Road

From online tracking to advanced scheduling systems, an innovative program and project management controls system is rapidly changing the face of bridge construction. Developed by the Virginia Dept. of Transportation (VDOT) in conjunction with consultant construction managers from McDonough Bolyard Peck Inc. (MBP), the system includes a pre-construction Critical Path Method (CPM) schedule solution to support the design and construction phases, as well as a web-based document and issue tracking system designed by the VDOT/MBP team.

Already put in practice on several bridge rehabilitation projects, the system enabled the design team to produce pre-construction CPM schedules. This allowed VDOT to “virtually build” the projects, and in doing so help the project team discover several potential improvements to the design and contract documents.

At the onset of construction, the designers teamed with contractors to use contractor-prepared CPM Schedules to plan work and track progress. Utilizing server-based Primavera Enterprise software, VDOT hopes to employ the Contractor’s schedule to forecast program resource needs, anticipate fiscal outlays, and manage inspection and engineering staff.

The contractors also used a web-based, password-protected document and issue tracking system to improve communication between the multiple levels of the DOT and the Contractor, helping to facilitate submittals, track requests for information, monitor due dates, track issue statuses, and much more.

Altogether, this combined project management controls system is developed to streamline the process, ultimately delivering a better product.

For more information about this innovative new program, contact McDonough, Bolyard & Peck Inc.

Specialists in Railroad Bridge Repair

Since 1954, Osmose Railroad Services has been serving the needs of our nation’s railroad industry. Experienced crews, backed by an in-house engineering group, have guided our focus to maintain and upgrade existing railroad structures. By pioneering the specialized service of detailed inspection followed by in-place preservative treatment, Osmose has extended the service life of thousands of timber bridges.

Upgrades to the structural integrity of steel and concrete bridges to handle the increasing pace of heavier axle loads have become a routine operation for Osmose. Strengthening key members such as floor systems, laterals and bearing areas are performed with the continual guidance of our knowledgeable engineering teams. In fact, our performance-based engineering techniques dovetail with our operations group to facilitate the most effective repairs based on track time and job complexity.

Turnkey design-build of new structures gives short-line and regional railroads the opportunity to make one phone call to complete their new bridge construction goals. This approach reduces costs associated with multiple partners, and speeds along the final implementation of the new structure, while maintaining the flow of railroad traffic.

With a service area extending over all of the U.S. and Canada, Osmose has the flexibility to direct crews specializing in various repair disciplines. With our hi-rail fleet of support vehicles, cranes and related equipment, Osmose has the ability to reach any structure in any location. Our on-going goal is to reduce maintenance costs while maintaining our customers’ current flow of railroad traffic. To accomplish these tasks, our work is dictated by the windows of time we receive. Then, our repair methods are modified to reflect these parameters.

Safety is the hallmark of any established company. All of our employees are trained annually in Federal Railroad Administration fall protection and track worker safety classes. This attention to safety is buttressed by quarterly updates in the field. For more information, visit www.osmose.com.

The Road to Cycle-Safe Bridges

SlipNOT Slip Resistant Construction Plates keep motorists and construction crews safe during rework on Weems Creek in Annapolis, Md.

Bridges can be a very unfriendly place for cyclists, bearing dangers that go well beyond the inherent hazard of riding within arm’s reach of vehicles moving at greater speeds. Dirt, debris and especially moisture can make an ordinarily smooth ride slippery and dangerous.
That’s why SlipNOT, developer of safety flooring products, adapted its patented cycle-safe gratings and plates to meet the needs of public and private bridge operators.

The SlipNOT Anti-Slip Perforated Plate is ideal for metal bridge decking, gangways, walkways and bicycle paths. Easily retrofitted to existing bridge decks, this non-slip system is durable, rust-proof and strong enough to withstand the wear of daily traffic for many years. The plates are actually created with molten metal that is applied directly to the plate and then bonded at over 4,000 lb per sq in.

Ideal for older bridges that were not originally designed to meet the current bridge safety standards, these plates are quick, easy and safe solutions to install on any bridge rehabilitation project. For more information, visit www.slipnot.com.

Taking the Edge Off Bridge Overhang Construction

The most difficult and expensive bridge construction element is the overhang. These segments are typically costly, require extensive safety measures and are time intensive— unless you build it on the ground first.

That's what Symons has done with its unique Bridge Overhang System, an all steel design that is assembled on the ground, providing a safer working environment, improved productivity and reduced cycle time. 

Safe Work Environment
Before they are lifted into place, the hangers that support the Bridge Overhang System are installed in the top of concrete beams. Even the guardrail posts and handrails remain in place until the system is disassembled at the end of the project. Any adjustments are safely made from the top of the bridge. There is no work activity outside the guardrail or under the suspended sections.

Increase Forming Productivity
The Bridge Overhang System sections are configured in standard 12-ft or 24-ft lengths. Only four bolts are required to attach the entire section, followed by fine grading. With a work crew of nine, 960 lineal ft (480 ft for each side) can be installed in one day.

Reduce Cycle Time 
All the operations associated with conventional overhang forming techniques are built-in features of the Bridge Overhang System. What once took five days is now routinely accomplished in one day.

Bridge Overhang System Basics: 
* Standard panel design accommodates bridge overhang widths up to 4 ft-6in.
* C- hook properly balances the section for safe and easy crane handling. 
* Adjusts to hanger spacing variations with 3 in. panel slots.
* Safely attach and remove sections with just 4 bolts from the top of the bridge.

This unique system provides better tolerances, a better finish and lasts for years with factory-built components that are securely bolted in place to maintain sharp, square corners and consistent results.

Corrosion Inhibitor Extends Life of Pennsylvania Bridge

Built in 1971, the Commodore Barry Bridge represents a major passageway linking Southeastern Pennsylvania & Southern New Jersey, transporting over 35,000 vehicles per day across the Delaware River.

By the mid-1990s, the bridge’s reinforced concrete deck was in need of rehabilitation. The main culprit was transverse cracking which allowed deicer salts to penetrate the bridge surface and initiate corrosion of the reinforcing steel.

Initial rehabilitation options such as latex-modified concrete overlays and waterproof membranes proved prohibitive due to their high costs, which were estimated in the range of $30 to $50 million. In 1997, the Delaware River Port Authority started evaluation of surface applied corrosion inhibitors as an alternative and cost-effective approach to remediate the bridge’s concrete deck.

After three years of field evaluation, Protectosil® CIT was selected as their product of choice to reduce future corrosion spalling.

Protectosil® is an organo-functional silane system designed to "short circuit" the corrosion current and creates passivity of the steel. Extensive laboratory testing on traverse cracking, and verified on the bridge deck, showed over 90% reduction in corrosion with the Protectosil® CIT.

In 2001 and 2002, the concrete was repaired and then Protectosil® CIT was applied to approximately 900,000 sq ft of bridge deck and approach ramps. The corrosion inhibitor treatment required only 5 hours to treat each lane, allowing for quick turnaround and reopening to traffic. Since that time, corrosion monitoring, using a linear polarization method, has confirmed the effectiveness of Protectosil® CIT.