According to a new report from the National Center for Policy Analysis (NCPA), America’s highways are getting safer and smoother. However, despite heavy subsidies, public transportation infrastructures are falling apart.

The report found that only 11 percent of America’s highway bridges were considered structurally deficient last year, down from 24 percent in 1990, the ACPA notes. The organization says that this is a sign of a transportation infrastructure that is continuously improving, says Randal O’Toole, a senior fellow at the Cato Institute and author of “Is U.S. Transportation Infrastructure Falling Down?” 

(For a proprietary report on the State of U.S. Bridges, see the Better Roads annual Bridge Inventory report.)

Because most of the nation’s highway infrastructure is still paid for through various user fees instead of government subsidies, O’Toole notes in an ACPA press release that “there has been ample funding to keep the nation’s roads in good repair.” Highways were actually an average of 20 percent smoother in 2009 than they were in 1989, according to the “roughness index” of the Department of Transportation.

O’Toole notes that these improvements have not been seen in America’s public transit systems. Despite overwhelming financial support, these transportation systems are routinely in disrepair and often request additional funds, ACPA says.

O’Toole cites these examples:

• In 2010, the Massachusetts Bay Transportation Authority needed $3 billion to bring the system to a state of good repair, but was able to find only about $200 million.
• The Federal Transit Administration reports the nation’s transit industry has a $78 billion backlog of work that must be done to bring transit infrastructure into a “state of good repair.”

He found that subsidies to public transit have not improved infrastructure or usage rates, partially because most of those subsidies don’t go to riders, but to increased profits for construction firms and increased pay and benefits for transportation workers, according to a press release from ACPA.

However, as an editor who has covered the transportation construction industry for the past nine years, I still think we are far from where we need to be with highway funding to keep our  bridges and roads in good condition. After nine extensions and nearly three years, we were finally able to get the reauthorization of the surface transportation bill, the Safe Accountable Flexible and Efficient Transportation Equity Act: A Legacy for Users (SAFETEA-LU), that expired in September 2009.

Alison Premo Black, Ph.D., senior economist for the American Road & Transportation Association (ARTBA), tells Randall-Reilly (RR) Business Media’s Construction Division (parent company of Aggregates Manager, Better Roads and Equipment World magazines) that although the paper addresses some of the physical attributes of the system, there is also an issue of congestion and increased demand on the system.

“Average yearly hours of delay per auto commuter have jumped from 19 hours in 1982 to 52 hours in 2010, according to the latest Urban Mobility Report from the Texas Transportation Institute,” Premo Black tells an RR editor. “This trend is seen across all urban areas – even smaller cities have seen an increase from an average of 5 hours of delay in 1982 to 18 hours in 2010.”

In an effort to raise public awareness about the safety and integrity of the new east span of the Bay Bridge, Caltrans Director Malcolm Dougherty called on the Sacramento Bee to retract a recent story that made false claims about the bridge.

In a letter to Sacramento Bee Executive Editor Joyce Terhaar, Dougherty outlines the major flaws in the May 27 story by reporter Charles Piller and calls on the paper to set the record straight. A Caltrans review of the Bee’s assertions has determined that they are completely inaccurate. Every part of the new span has been thoroughly tested by expert engineers and independent experts who have determined that the bridge is safe and sound.

“The safety of millions is dependent on the engineering work we do on structures like the Bay Bridge,” writes Dougherty. “As public servants, we are not beyond criticism or questioning of how we do our jobs, but we ask that you understand your unique responsibilities to present a fair picture of our work. We also expect you to get it right.”

Director Dougherty also took the opportunity to reassure Californians that the new eastern span of the Bay Bridge meets or exceeds all safety standards.

“Every concrete pile in the new bridge’s tower foundation has passed three rigorous, mandatory safety tests,” said Dougherty. “The tower foundations were designed to exceed normal safety standards. Every aspect of the bridge has been tested, checked and rechecked multiple times. These tests were reviewed by a panel of internationally-renowned experts who have confirmed the integrity and seismic safety of the bridge.”

Director Dougherty’s letter to the Sacramento Bee follows:

June 7, 2012

Ms. Joyce Terhaar
Executive Editor, Sacramento Bee
2100 Q Street
Sacramento, CA 95816

Ms. Terhaar:

I am writing to formally request that the Sacramento Bee immediately print a retraction of the story, “Records Raise Doubts on Bay Bridge Concrete,” which ran in your paper on May 27, 2012.

The story contains false information and a selective reading of records gathered by your reporter.

·        Your reporter was given voluminous evidence that contradicts the story’s conclusion that the bridge foundations were inadequately tested.
·        Evidence suggests that your reporter failed to test the accuracy of his claims and omitted information that contradicted his conclusion.
·        The story includes unsubstantiated and untrue accusations that Caltrans officials misrepresented or dismissed important engineering evidence during bridge construction.
·        Your reporter denied Caltrans representatives the opportunity to fully respond to “expert” and anonymous opinions he solicited for the story.
Caltrans takes this breach of the public’s trust seriously and raises the following specific examples of inaccurate and misleading reporting in “Records Raise Doubts on Bay Bridge Concrete.”

The story claims that Caltrans was “prevented” from doing “further examination or repair” on Pile 3 because Caltrans did not see a subcontractor’s report identifying a 19-foot anomaly using “crosshole sonic logging (CSL)” in Pile 3.

This is false. It incorrectly represents the role and requirements for CSL and it is contradicted by records that were supplied to the reporter.

·        Caltrans did substantial further examination. The concrete in Pile 3, as in all the piles, was designed to meet certain strength requirements, not to set in a short period of time. Concrete for Pile 3 was tested 28 days after it was poured and met strength requirements. The contractor tested Pile 3 on day four – a full 24 days before the Caltrans test. Caltrans uses cylinder break tests to assess concrete strength, and checks this over extended intervals, sometimes in as little as 14 days after concrete is poured and in some cases as long as 56 days after concrete was poured.
·        The story makes an unsubstantiated hypothesis that a concrete additive may have been overused, which is directly contradicted by certifications and factual records indicating consistent, correct concrete mix was produced. This was verified by inspection, slump and cylinder break tests.
·        Subsequent tests and examinations by Caltrans showed that Pile 3 had, in fact, set and was sound:
o        Eleven days after the concrete was poured, and seven days after the CSL test, the contractor conducted “chipping” on Pile 3. This is a practice in which they jackhammer away at the top of a pile until we are satisfied we have hit solid, pure concrete. Chipping on Pile 3 showed that the concrete had set. The chipping record was supplied to your reporter.
o        Seven days after the concrete was poured, and three days after the CSL test, Caltrans tested Pile 3 using “Gamma-Gamma Logging” (GGL) technology. This test shows whether there are significant anomalies in the concrete. The test showed that Pile 3 had no significant anomalies. A record of this Gamma-Gamma Logging test was supplied to your reporter.
o        Twenty eight days after the concrete was poured, and 24 days after the CSL test, Pile 3 was subjected to a “cylinder break test,” which showed the concrete in Pile 3 was set and solid. Information on this test was supplied to your reporter.
The story contains multiple unsubstantiated assertions in the editorial voice: “Suspicious concrete,” “suspect and inadequately tested concrete,” “poor concrete.” These phrases appear without attribution, and hang on false and misleading information about the tests.

·        Take the very test results that your reporter bases this entire story upon, the Crosshole Sonic Logging test conducted by Olson Engineering. In his story, your reporter writes that Olson detected the “problem concrete” in Pile 3 in 2007 and “suggested new sonic tests.” This is not accurate.
·        Olson suggested new sonic tests or a gamma-gamma test. Caltrans performed the GGL tests, consistent with Olson’s suggestion, three days after the cross hole sonic test and seven days after the concrete was poured. This test showed the concrete had no significant anomalies and had the required density. Again, the reporter was given all this information but he omitted Olson’s suggestion that gamma-gamma tests could be performed in lieu of sonic tests, creating the false impression that Caltrans failed to verify the safety of the pile.
The Bee’s reporting on Pile 8 similarly relies on conclusions invented by the reporter. He asserts that Pile 8 had “inferior concrete” was “plagued by test and construction problems” and was beset by “construction abnormalities” without providing any evidence to support this editorializing.

·        His evidence seems to be that workers chipped for six days on the concrete in the course of their normal examination and protocol instead of three.
·        The number of days spent on chipping is irrelevant and has nothing to do with the quality of concrete. The statements concerning Pile 8 have no basis in fact and are presented merely to support a theory invented by the reporter.
·        All tests – the “slump test” performed during the pour, the “break test,” the GGL tests performed after the pour and the chipping – show no abnormalities and give Caltrans confidence that this pile is safe. This information was shared with your reporter
While Caltrans can show numerous other examples in this story that show how your reporter built a thesis on a faulty foundation, I close with a fact that should give the Sacramento Bee cause for concern as an institution.

·        According to our records, your reporter last contacted Caltrans with substantive questions regarding the testing and construction of the bridge foundation on April 30, a full 27 days before his story was printed.
·        He never gave Caltrans an opportunity to fully respond to his baseless allegations or his invented theories about concrete drying.
·        He never asked Caltrans to fully respond to false allegations made by an anonymous source.
·        He gathered preliminary information from Caltrans in April, and apparently spent 27 days attempting to knock it down without circling back for our response.

If Caltrans had constructed the new span of this bridge the way this story appears to have been constructed, Californians would have reason to worry. Instead, Caltrans’ records show a pattern of care and quality assurance at every stage of the Bay Bridge project. Your reporter was given all of this information and documentation. Unfortunately for your readers, it didn’t make it into the paper.

Caltrans takes its job seriously. The safety of millions is dependent on the engineering work Caltrans does on structures like the Bay Bridge. As public servants, Caltrans is not beyond criticism or questioning of how we do our jobs, but we ask that you understand your unique responsibilities to present a fair picture of our work. Caltrans also expects you to get it right. Your reporter had the information to do this, but he chose to ignore it. It is for this reason Caltrans asks for a full retraction of the story.

Sincerely,

Malcolm Dougherty
Director

To learn more about rope access for bridge inspections, click here for a downloadable PDF of “Climbing Techniques for Bridge Inspection.”

The new agreement, which was made in December with the University of Illinois, “demonstrates the Illinois Tollway’s commitment to collaborate with local universities, research institutions and laboratories on new initiatives to reduce costs of capital improvements, foster environmental sustainability and improve the efficiency and safety of maintenance and operations,” the Illinois Tollway noted in a press release.

“The University of Illinois is uniquely qualified to partner with us on this research based on their strong record of leadership and innovation,” said Illinois Tollway Executive Director Kristi Lafleur in a written statement. “This research will help us design new bridges on our system that are less expensive to build, will last longer and will result in fewer disruptions for Tollway customers due to maintenance and repairs.”

Research conducted by the ICT will include an analysis of new bridge design and construction under the Tollway’s new $12 billion, 15-year capital program, Move Illinois: The Illinois Tollway Driving the Future. The Tollway plans to include designs for jointless bridges in the new Jane Addams Memorial Tollway (I-90) corridor from the Tri-State Tollway (I-294) to the I-39 interchange in Rockford, reconstruction of the central Tri-State Tollway (I-294) from 95th Street to Balmoral Avenue and the Edens Spur (I-94), as well as in the construction of the new, Elgin O’Hare West Bypass.

“The ICT and the University of Illinois are very pleased to partner with the Illinois Tollway and the Illinois Department of Transportation to conduct important research that will result in safer bridges and reduced construction and operation costs, while minimizing traffic disruption,” said Imad Al-Qadi , director of the Illinois Center for Transportation and founder professor of engineering in the Department of Civil and Environmental Engineering at the University of Illinois at Urbana-Champaign.

Under the agreement, the Tollway will collaborate with ICT and the Illinois Department of Transportation in exploring issues related to the analysis, design, construction and maintenance of jointless bridges. The research will also seek ways to reduce or eliminate the use of bridge expansion joints whenever possible on these new structures, providing opportunity to reduce construction and maintenance costs.

Jointless bridges have been proven to be more cost-effective than conventional bridges, as jointless bridges require less maintenance and have a longer service life. Conventional bridges are costlier to maintain because joints commonly leak when exposed to rain and snow and must be replaced every seven to 10 years. These leaks cause corrosion and degrade concrete structures, which shortens the overall life of a typical bridge.

In addition, ICT will generate design guidelines and construction specifications for jointless bridges that meet Tollway standards and continue to monitor the performance of jointless bridges during and after construction under the terms of the $67,000-a-year agreement.

The society annually recognizes an exemplary civil engineering project that best illustrates superior civil engineering skills and represents a significant contribution to civil engineering progress and society. The Whittier Access Tunnel, another HDR project, won an OCEA award in 2001.

The Hoover Dam Bypass project dates back to 2001, when the Federal Highway Administration, Central Federal Lands Highway Division (CFLHD) awarded a contract to HDR to provide design and construction support services for the project. Under the management of CFLHD, HDR led an integrated team of professionals from HDR, T.Y. Lin International and Jacobs Engineering (formerly Sverdrup) and several specialty subconsultants.

The bypass is the innovative solution to the challenge of improving mobility and safety in the dam vicinity and enhancing the economic capacity of the route that passes through the area. It includes the landmark 1,900-foot-long Mike O’Callaghan-Pat Tillman Memorial Bridge over the Colorado River, 1.2 miles of approach roadway and two bridges in Arizona, and 2.3 miles of roadway and six bridges in Nevada.

Besides managing the design of the entire project, HDR also shared design for the river bridge, and provided detail design for the Nevada approach and five other approach bridges, including the Gold Strike Canyon crossing. The river bridge is the highest and longest arched concrete bridge in the Western Hemisphere and features the world’s tallest precast concrete columns. The innovative hybrid structure is designed to complement the dam with the high-performance concrete arch, while limiting the load demands with a modern steel superstructure. It is the first steel-concrete hybrid arch bridge in the United States.

The Hoover Dam Bypass previously won the Grand Conceptor Award, the highest national honor bestowed by the American Council of Engineering Companies, among several additional awards.

Residents and local businesses depend heavily on this bridge, which is why NYSDOT says it “worked diligently” to re-open it as quickly as possible. The bridge was originally scheduled to be re-opened in early April. “Under the leadership of Governor [Andrew M.] Cuomo, the department was able to expedite emergency repairs to the former Route 219 Bridge which provides a local transportation link between Erie and Cattaraugus counties,” Kaminski said in a press release. “It was important to re-open the bridge to traffic because it not only serves local mobility and transportation needs, but it has a direct impact on the local economy of the surrounding communities.”

The bridge was closed to all traffic on Jan. 5, 2012, due to structural concerns caused by frozen bridge bearings. NYSDOT invoked an emergency contract to accelerate the replacement of the bridge abutment bearings and return traffic to the bridge. Several regional public officials joined Kaminski to commemorate the reopening.

“Our infrastructure is suffering from a crippling lack of investment and our economy is paying the price, as evidenced by the devastating impact the sudden but necessary closing of the bridge had on the local business community,” Democrat Rep. Brian Higgins (NY-27) said in a written statement. “According to Transportation for America report, the Buffalo Niagara region ranks thirteenth worst in the nation, among similar sized communities in terms of deficient bridges. In this instance, the New York State Department of Transportation was able to act swiftly to address safety issues, and we are thankful for their efforts. This however, should be a wake-up call. The best way to create economic growth is to create jobs and the best way to create jobs is to invest aggressively in infrastructure. There is a great amount of work that needs to be done and Western New Yorkers certainly need the work.”

Republican Rep. Tom Reed (NY-29), also noted in a written statement: “This bridge is a main conduit and having it open again is vital to those in both Cattaraugus and Erie Counties. I thank all the local and state officials and agencies who kept this project as a top priority and made this happen.”

New York State Sen. Catharine Young (R,C,I-57th District) says re-opening the bridge in such a short period of time “is truly is a remarkable feat. When the bridge closed, the future was murky. It wasn’t clear if it ever could be open for traffic again, which would have killed small businesses and hurt the quality of life for local residents.” However, Young lauds Gov. Cuomo for “stepping up to the plate.”

She says he worked to come up with Sen. Gallivan (R,C,I – 59th District), the NYSDOT and herself to come up with a speedy solution. “Word that traffic will be restored to the Old 219 Bridge is long-awaited and welcome news for the Village of Springville,” Gallivan said in a press release. “Since the bridge’s abrupt closure in January, I have worked every day with transportation officials in Western New York and in Albany to restore bridge traffic as soon as safely possible; I thank them for their cooperation. But the most important efforts came from those impacted most – the people and businesses of Springville. Without their persistence and commitment, I don’t think we would be celebrating the re-opening of this bridge ahead of schedule, as we are today. They deserve all the credit in the world.”

The emergency bridge repairs were completed under the statewide emergency bridge contract which was awarded to D.A. Collins Construction Company of Wilton, Saratoga County. Although traffic will be crossing the bridge, crews will still be on site during the next several weeks to finish detail work.

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Piece by piece and steel girder by girder, the five-level construction marvel known as the new Sam Rayburn Tollway/Dallas North Tollway (SRT/DNT) interchange is taking shape in Collin County.

In fact, during the next seven to eight months, construction crews will set all the steel beams that form the heart of the new interchange. The steel will help create eight direct-connecting bridges that will join the two major toll roads and effortlessly move traffic through what has been a highly congested area.

During this ongoing phase of construction, the steel beams are on center stage. Every weekend, crews use massive cranes to hoist two enormous steel beams at a time and then bolt and weld them into place.

Each beam section is about 300 feet long — meaning that if a beam section were placed on its end, it would be slightly taller than the new Cowboys Stadium or about as tall as a 20-story building. It would be barely shorter than the Statue of Liberty, from the base of the monument’s pedestal foundation to the tip of its torch.

When the SRT/DNT interchange is complete, crews will have set more than 18 million pounds of steel bridge beams — an amount equal to about 10,000 automobiles, more than the Eiffel Tower and more than the state of Texas bid out in 2010 for use in transportation projects.

Between now and when the last beam is placed, crews will continue to close SRT and DNT main lanes and frontage roads as necessary, primarily on Friday evenings through early Monday mornings. The closures are required to ensure the safety of motorists as well as NTTA contractors and staff as the steel beams are being set.

“We know these closures affect motorists and businesses, and we want to thank everyone for their patience while we complete the interchange,” said Elizabeth Mow, NTTA director of project delivery. “We promise that the pain will be worth the gain. We are building a significant, five-level interchange that will vastly improve regional mobility and further encourage the ongoing economic development in the area.”

The five-level SRT/DNT interchange by the numbers:

The interchange will be about 105 feet tall from the lowest roadway surface to its highest bridge.

o The SRT/DNT interchange will be about as tall as a seven-story building. By comparison, the High Five in Dallas is about as tall as a 12-story building.

o The SRT/DNT will feature more than 18 million pounds of steel beams.

This amount of steel:
o Is equal to the steel used to build about 10,000 automobiles.
o Weighs more than the steel in the Eiffel Tower.
o Is more than the state of Texas bid out in steel beams on transportation projects in 2010.

The steel beams are placed in sections that are about 300 feet long, which is as long as a football field. If stood on its end, the longest beam section would be:
o Slightly taller than the new Cowboys Stadium (which has a peak height of 292 feet)
o About as tall as a 20-story building.
o More than 50 feet taller than the tallest water tower in the City of Frisco.
o Barely shorter than the Statue of Liberty monument, from the pedestal foundation base to the tip of the torch (which is 305 feet, 6 inches tall).

A total of 30,000 linear feet of steel beams is being used in the interchange. This amount:
o If placed end to end, would reach the cruising altitude of many jetliners.
o Equals about 5.7 miles — a length that would wrap around the nearby IKEA building more than 15 times.

Crews are hoisting and setting two steel beams at a time, and the typical beam weighs between 500 pounds and 600 pounds per foot.
o The heaviest section weighs close to 200 tons, a weight comparable to lifting five typical backyard swimming pools full of water.
o On a typical weekend beam placement operation, crews have to line up and tighten into place nearly 2,500 bolts.
o Project-wide, nearly 150,000 bolts and miles of welds will be used to fabricate and secure all the steel beams in place.

This article was contributed by the North Texas Tollway Authority (NTTA)

Integral Abutment Bridges

A survey on the status of use, problems and costs associated with integral abutment bridges

by Andreas Paraschos, P.E. and Amde M. Amde, P.E.

(For an unedited, downloadable PDF of the Integral Abutment Bridges article, click here. )

Integral abutment bridges provide an excellent alternative to conventional bridges built with bearings and expansion joints. Integral abutment bridges incur lower construction and maintenance costs compared to conventional bridges. In addition, they have a longer service life and a superior seismic performance compared to conventional bridges. Forty-one states are now using integral abutment bridges. Despite their wide acceptance by state transportation agencies and the engineering community in general, however, use of integral abutment bridges for long bridges and in situations that involve complex structural and soil conditions is still limited.

This article presents the findings of a survey conducted in 2009 by the University of Maryland at College Park that focuses on state integral abutment bridge practices. It summarizes the responses received from the states with regard to the status of use, problems and costs associated with the use of integral abutment bridges.

The Problem with Deck Joints

Early bridge structures were designed as a series of simply supported structures. With the introduction of the Moment Distribution Method in 1930, structural engineers began to design bridges as continuous structures. As a result, it became possible to construct longer bridges. Deck joints were provided in bridges in order to accommodate deck expansion and contraction without compromising the structural integrity of the bridges.

The introduction of deck joints created many problems to bridge owners. Joints are expensive to buy, install, maintain and repair. Repair costs are high. The joints leak throughout time, allowing deicing chemicals to attack the girder ends, bearings and supporting reinforced concrete substructures. The result is corrosion and deterioration of girders, bearings and substructure. Bearings are also expensive to buy and install, and are more costly to replace. Throughout time, steel bearings malfunction due to loss of lubrication or buildup of corrosion. Elastomeric bearings can split and rupture due to unanticipated movements. Because of these problems, it is necessary to continually inspect, maintain and periodically replace the joints. The use of expansion joints and bearings to accommodate thermal movement does not alleviate maintenance problems.

Integral abutments eliminate the need to provide deck joints. In addition, they can save bridge owners a considerable amount of money, time and inconvenience compared to conventional abutments. Because of these reasons, states began building integral abutments. Colorado was the first state to build integral abutments in 1920. Massachusetts, Kansas, Ohio, Oregon, Pennsylvania and South Dakota followed in the 1930s and 1940s. California, New Mexico and Wyoming built integral abutment bridges in the 1950s.

With the National Interstate Highway System construction boom in the late 1950s and mid-1960s, Minnesota, Tennessee, North Dakota, Iowa, Wisconsin and Washington began moving toward continuous bridges with integral abutments as standard construction practice. A testament of their excellent performance throughout the years is the fact that the current policy of the vast majority of states is to build integral abutment bridges whenever possible. This is confirmed by the results of this survey, which indicates that forty-one states are now using integral abutment bridges.

Problems with integral abutment bridges do exist; the severity and cause of problems differ from state to state. The state responses to the 2009 survey on integral abutment bridges conducted by the University of Maryland are shown in Tables 1, 2 and 3. This paper focuses on responses to the following three issues: status of use of integral abutment bridges, problems associated with integral abutment bridges, and construction and maintenance costs of integral abutment bridges compared to conventional bridges. Forty-seven states responded to the survey; responses were not received from Montana, Rhode Island and South Carolina.

Fig. 1. Evolution of integral abutment bridges in the United States.

Use and Problems Associated with Integral Abutment Bridges

The 2009 survey on integral abutment bridges conducted by the University of Maryland indicates that forty-one states are now using integral abutment bridges. Colorado pioneered the use of integral abutment bridges in 1920 followed by Massachusetts in 1930, and Kansas and Ohio in 1935. Eight states — Missouri, Tennessee, California, Iowa, Illinois, Kansas, Washington and Wyoming — have more than 1,000 integral abutment bridges in their inventories. Missouri has more than 4,000 integral abutment bridges and Tennessee has more than 2,000. The state of Washington, having built more than 1,000 integral abutment bridges by the year 2000, has decided to switch to semi-integral abutments.

In addition to being the first state to build integral abutment bridges, Colorado has the longest steel-girder integral abutment bridge in the United States with a length of 1,044 feet and the longest cast-in-place concrete integral abutment bridge with a length of 952 feet. The longest precast concrete integral abutment bridge in the United States was built in Tennessee; it has a length 175 feet.

Table 1 shows responses regarding status of use of integral abutment bridges and problems associated with integral abutment bridges.

Costs Associated with Integral Abutment Bridges

The 2009 survey on integral abutment bridges also addresses the issue of costs associated with the use of integral abutment bridges. Tables 2 and 3 show the state responses on the issue of construction and maintenance costs of integral abutment bridges compared to conventional bridges.

Summary of Responses

The responses to the survey indicate that nine states do not use integral abutment bridges. Out of the nine states that do not use integral abutment bridges, three states (Alabama, Delaware and Louisiana) never used integral abutments, three states (Alaska, Arizona and Mississippi) discontinued their use due to serious problems, and three states (Florida, Texas and Washington) discontinued their use either because they realized no performance advantage over their conventional practice (Florida and Texas) or they concluded that semi-integral abutments offer more advantages compared to integral abutments (Washington). The status of use of integral abutment bridges is illustrated in Figure 2.

The responses also indicate that 25 states have no problems with the use of integral abutment bridges. In addition, 12 states (California, Colorado, Maine, Michigan, Missouri, Nebraska, New Mexico, New York, North Carolina, Oklahoma, Utah and West Virginia) report either minor or moderate problems with the use of integral abutment bridges. Four states (Indiana, Kansas, South Dakota and Virginia) had moderate problems with integral abutment bridges in the past; they found a solution to their problems and do not report any more problems. However, three states (Alaska, Arizona and Mississippi) had serious problems with integral abutment bridges; as a result, each state discontinued their use. The status of problems with integral abutment bridges is illustrated in Figure 3.

The responses to the issue of construction costs of integral abutment bridges compared to conventional bridges indicate a lower construction cost in twenty-seven states, higher construction cost in five states (Arkansas, Georgia, Maryland, Nebraska and Utah), and same construction cost in three states (Indiana, Kansas and New Hampshire). The status of construction costs of integral abutment bridges and conventional bridges is illustrated in Figure 4.

The responses with regard to the issue of maintenance costs of integral abutment bridges compared to conventional bridge indicate a lower maintenance cost in thirty-two states, and same maintenance cost in three states (Georgia, Hawaii and Nebraska). Not surprisingly, no state reports a higher maintenance cost with the use of integral abutment bridges. The status of maintenance costs of integral abutment bridges and conventional bridges is illustrated in Figure 5.

Forty-one states use integral abutment bridges. The number of integral abutment bridges, both statewide and nationwide, has increased considerably in the last few decades. Eight states have more than 1,000 integral abutment bridges; among them, Missouri with more than 4,000 and Tennessee with more than 2,000 integral abutment bridges. The responses received from the state departments of transportation confirm the fact that use of integral abutment bridges almost always results in lower bridge maintenance costs compared to conventional bridges. The responses also confirm that in the vast majority of states, the construction cost of building integral abutment bridges is lower compared to conventional bridges.

In addition, most states report no problems with integral

Figure 5 Status of comparative maintenance costs of integral abutment and conventional bridges

abutment bridges; a limited number of states report minor to moderate problems with the use of integral abutment bridges. A number of states that previously had problems with integral abutment bridges were able to come up with solutions to these problems. As a result, they do not report any more problems with the use of integral abutment bridges.

However, it is very important to recognize that many problems are avoided because integral abutment bridges are built within the limitations imposed by the design parameters outlined in each state’s Bridge Design Manual. These design limitations prohibit the use of integral abutments for very long bridges and in situations that involve complex structural and soil conditions. In addition, there are limitations on skew, curvature and type of piles to name a few.

Apparently, more research on integral abutments is needed in order to advance the use of integral abutment bridges. More research that predicts the behavior of integral bridges based on theory, in addition to empirical evidence will lead to the introduction of national guidelines for integral abutment bridges, which will provide legitimacy to this cost-effective method of bridge construction. The current absence of such a document acts as a deterrent to the use and further advancement of integral abutment bridge construction.

Acknowledgments from the Author

This article is based upon the responses received from the following state departments of transportation: Alabama, Alaska, Arizona, Arkansas, California, Colorado, Connecticut, Delaware, Florida, Georgia, Hawaii, Idaho, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maine, Maryland, Massachusetts, Michigan, Minnesota, Mississippi, Missouri, Nebraska, Nevada, New Hampshire, New Jersey, New Mexico, New York, North Carolina, North Dakota, Ohio, Oklahoma, Oregon, Pennsylvania, South Dakota, Tennessee, Texas, Utah, Vermont, Virginia, Washington, West Virginia, Wisconsin and Wyoming. Their help is gratefully acknowledged.

Amde M. Amde (formerly Amde M. Wolde-Tinsae) is a professor of structural engineering in the Department of Civil and Environmental Engineering at University of Maryland. He is also a registered professional engineer and president of AMA & Associates. Other faculty positions held include Iowa State University and McMaster University. He holds two U.S. patents and has published more that 200 technical papers.

Andreas Paraschos is a professional engineer in the state of New York and a structural bridge engineer with the New York City Department of Transportation/ Division of Bridges.

Andreas Parachos

References

1.    Amde, A.M., Chini, S.A. and Mafi, M., “Experimental Study of Piles in Integral Abutment Bridges,” International Journal of Geotechnical and Geological Engineering, 1997, Vol. 15, 343-355.

2.    Amde, A.M. (Wolde-Tinsae, A.M.) and Klinger, J., The State-of-the-Art in Integral Abutment Bridge Design and Construction, AW087-313-046, FHWA/MD-87/07, January 1987, 70 pages.

3.    Amde, A.M. (Wolde-Tinsae, A.M.), Klinger, J. and White, E.J., “Performance of Jointless Bridges,” Journal of the Performance of Constructed Facilities, ASCE, Vol. 2, No. 2, May 1988, pp. 111-125

4.    Amde, A.M. (Wolde-Tinsae, A.M.) and Greimann, L., “General Design Details for Integral Abutment Bridges,” Journal of Civil Engineering Practice, BSCE/ASCE,ISSN: 0886-9685, Vol. 3, No. 2, Fall 1988, pp. 7-20.

5.    Amde, A.M. (Wolde-Tinsae, A.M.), Greimann, L., and Johnson, B., “Performance of Bridge Abutments,” The Journal of the International Association for Bridge and Structural Engineering, IABSE PERIODICA 1/1983, pp. 17-34.

6.    Amde, A.M. (Wolde-Tinsae, A.M.), Greimann, L.F., and Yang, P.S., “End Bearing Piles in Jointless Bridges,” Journal of Structural Engineering, ASCE, Vol. 114, No. 8, August 1988, pp. 1870-1884.

7.    Burke, M.P.,”Integral Bridges.” Transportation Research Record, No. 1275, 1990, pp. 53-61.

8.    Greimann, L. and Amde, A.M. (Wolde-Tinsae, A.M.), “Design Model for Piles in Jointless Bridges,” Journal of Structural Engineering, ASCE, Vol. 114, No. 6, June 1988, pp. 1354-1371.

9.    Greimann, L.F., Amde, A.M. (Wolde-Tinsae, A.M.) and Yang, P.S., “Skewed Bridges with Integral Abutments,” Bridges and Culverts, Transportation Research Record 903, Transportation Research Board, National Academy of Sciences, Washington, D.C., 1983, pp.64-72.

10. Kunin, J., and Alampalli, S, “Integral Abutment Bridges: Current Practice in the United States and Canada,” Special Report 132, Transportation Research and Development Bureau, New York State Department of Transportation, Albany, N.Y., 1999.

11. Maruri, R., and Petro, S, “Integral Abutments and Jointless Bridges 2004 Survey Summary.” Federal Highway Administration and Constructed Facilities Center at West Virginia University, Morgantown, W.V.