Pick Your Poison

March 26, 2007

Tallness has its advantages. According to a pair of Louisiana State University (LSU) researchers, the main distinction between bridges that survived Hurricane Katrina and those that did not is that the survivors were high enough to stay above the storm surge.

“The general conclusion is that it’s damage by the water not by the wind,” Steve Cai, an assistant professor of civil and environmental engineering at LSU, told Roads & Bridges. “Of course, the conclusion is not final yet. It could be a combination between water and the wind.”

Tallness has its advantages. According to a pair of Louisiana State University (LSU) researchers, the main distinction between bridges that survived Hurricane Katrina and those that did not is that the survivors were high enough to stay above the storm surge.

“The general conclusion is that it’s damage by the water not by the wind,” Steve Cai, an assistant professor of civil and environmental engineering at LSU, told Roads & Bridges. “Of course, the conclusion is not final yet. It could be a combination between water and the wind.”

Ayman Okeil, also an assistant professor of civil and environmental engineering at LSU, is Cai’s colleague on a National Science Foundation (NSF) grant to document the damage done to bridges by Katrina. The bridge-damage component is only part of the $30,000 grant, so it was eligible for fast approval.

Cai also is leading a larger grant, worth $310,000, also funded by NSF, with Marc Levitan and Dimitris Nikitopoulos as co-principal investigators, to study the general effects of hurricanes on long-span bridges. Work on the smaller grant may be wrapped up by this October. The larger study is in its third year and will continue for some time.

Although the definition of what is a long-span bridge and what is a short-span bridge is fuzzy, a short span is shorter than about 70 ft; a medium span is about 70 to 450 ft; and a long span is longer than about 450 ft.

An example of a short-span bridge that suffered much damage from Katrina is I-10 across Lake Pontchartrain. There, many of the superstructure segments were shoved off their supports by the water. (See The fast life, p 22) Cai thinks bridge engineers should take more consideration of the load put on a bridge by a hurricane’s wave surge, which for a Category 4 or 5 storm can reach a height of 20 ft.

People who are not bridge engineers might think the solution is to attach the superstructure tighter to the substructure, but engineers know better.

“If the tie is too weak, then it is very easy to blow away, but if the tie is too strong, then you may transfer too much force to the substructure, to the foundation,” Cai said. A damaged bridge foundation is far more expensive to repair than a damaged superstructure. “So you need to make a sort of balance.”

So what should bridge builders do to protect their bridges from future hurricanes? Cai’s preliminary, qualified recommendation is to build them higher.

“The problem is that if you build the profile higher, it definitely costs more money. Even if you build the profile higher, you still have a transition area near the end of the bridge. The bridge in the middle may be high enough, but the bridge near the shore, that part still could be in the water.”

The type of railing on the bridge is another factor Cai and Okeil are looking at: “If the railing system is solid or open that could affect the loading,” Cai said. “If it’s open the water can pass through, and if it’s solid then you pick up more load.”

Cai also is studying a couple of bridges that survived Katrina. There is a bridge that runs parallel to I-10. “That bridge has no problem,” said Cai. There also is a railroad bridge that runs parallel to U.S. 90 along the Gulf Coast. The railway bridge is only a few hundred feet away from a U.S. 90 bridge. The U.S. 90 bridge suffered major damage, whereas the railway bridge was untouched.

Quick comeback for La. bridge

Cutting the ribbon to open the westbound lanes of the I-10 “Twin Spans” on Jan. 5 was another step in Louisiana’s long recovery from Hurricane Katrina.

“This bridge is a metaphor for Louisiana; it symbolizes our present and our future,” said Louisiana Gov. Kathleen Babineaux Blanco. “It was broken, but will return Friday to functioning at capacity. And when the new ‘twin spans’ are built, capacity will grow by one-third with the addition of third lanes.”

Speakers at the ribbon cutting included Blanco, acting Federal Highway Administrator J. Richard Capka, Louisiana Department of Transportation and Development (DOTD) Secretary Johnny Bradberry and Boh Bros. President Robert S. Boh, the contractor for the work.

The westbound lanes officially reopened at around 6 a.m. Friday, Jan. 6, eight days ahead of schedule. The eastbound left lane was scheduled to be closed during off-peak hours for three days thereafter to allow for restriping of the bridge back to one-way operation.

Repairs started on a 24-hour-a-day, seven-day-a-week schedule on Sept. 12, two weeks after a storm surge during Katrina knocked 435 segments weighing 309 tons out of alignment. Sixty-four segments were damaged so badly they had to be discarded.

The eastbound structure reopened Oct. 14, 2005, and handled two-way traffic while the westbound lanes were still under construction.

The cost of repairing the twin spans totaled about $35 million, up $4.1 million after a change order to have two westbound lanes instead of one in the repair contract.

DOTD Secretary Bradberry noted that the department has a special traffic management plan in place for the repaired bridge, including a lower speed limit of 50 mph on the westbound side and 60 mph on the eastbound side, strategically placed variable-message signs that can be programmed remotely to warn of fog or accidents and the operation of two Motorist Assistance Patrol vans from U.S. 11 to Oak Harbor/Eden Isle 16 hours a day, seven days a week.

An average of nearly 55,000 vehicles per day traveled the 5.4 miles across Lake Pontchartrain on the twin spans prior to the storm.

(See feature article on p 22 for more information about the reconstruction of I-10.)

Calif. to pump up economy with transportation projects

California Gov. Arnold Schwarzenegger hopes to pump $107 billion into the state’s economy through transportation projects over the next 10 years. The transportation plan is part of an overall $222 billion public works proposal the governor announced in early January, the San Francisco Chronicle reported.

Starting in June with a $6 billion bond on the ballot, Schwarzenegger wants to propose bonds for highways, transit systems, flood-control projects, port improvements, jails, courts, levees and construction and modernization of public schools and universities.

Existing revenue streams—in the form of gas taxes, federal matching funds and other sources—should produce about $47 billion in transportation funding by 2016, Schwarzeneggar figures. Another $14 billion should be generated by requiring private entities to match state bond funds that benefit them.

The governor’s plan includes many other measures for construction on public works projects with bond proposals to pay for them.

Before Republican lawmakers will agree to a bond proposal, the San Francisco Chronicle reported, they want a series of changes to state law to benefit business, such as relaxing requirements for environmental reviews of construction projects. Democrats are likely to oppose such changes.

Gov’s plan for roads, schools mired in state politics

Illinois Gov. Rod Blagojevich unveiled a $3.2 billion plan on Jan. 10 to improve roads, schools and mass transit, but Illinois Republican lawmakers immediately signaled their inclination to oppose the Democratic governor’s program, the Chicago Tribune reported, and accuse him of playing politics with construction projects.

The governor announced his plan on a tour of southern Illinois, where Republican voters who supported him in his 2002 election are now unsatisfied with him. Blagojevich will need some Republican support to get a bond-funded public-works program approved by the state legislature. Such programs require a three-fifths supermajority to pass.

Blagojevich’s proposal would use existing road funds, funded primarily with motor-fuel taxes, and increasing tax receipts to pay for $2.7 billion in bonds to finance highway construction and mass transit. Also a part of the proposal is $500 million to construct new schools to be paid for with revenue from new keno games in bars and restaurants.

The governor said the plan would create 230,000 jobs in the state and bring Illinois greater access to federal transportation and school funding.

Blagojevich’s opponents call the plan a campaign ploy.

“This is a standard M.O. for the Blagojevich administration, to go for press releases and headlines instead of substance,” Patricia Shuh, a spokeswoman for Senate GOP leader Frank Watson, told the Chicago Tribune. “What he has laid out is a press release, not a road program. A road program has details. . . . We’ve seen none of that.”

Site of new bridge yields Colonial-era Va. artifacts

At the site of a future bridge over the Chickahominy River, archaeologists for the Virginia Department of Transportation (VDOT) are finding a wealth of Colonial-era artifacts, the Richmond Times-Dispatch reported.

The hand-wrought nails, pewter spoons, stemmed glassware and ceramics dating from 1750-1780 are among the structural components and housewares found at the site. Evidence suggests the artifacts are associated with the Barrett family plantation that existed in the area around 1750.

The VDOT archaeologists discovered the artifacts while investigating the site of the future replacement of the Judith Stewart Dresser Memorial Bridge, which carries Rte. 5 between James City County and Charles City County. The researchers investigate sites of proposed construction to minimize damage to sites with cultural or historical significance.

“The site has excellent potential to yield information on themes and questions related to the history of James City County and the surrounding region,” said John Wells, preservation program manager for VDOT’s Richmond District.

“We’re gathering as much information and as many artifacts as we can from the site because when we’re finished, the site is going to be destroyed” in constructing the bridge, Wells said.

The archaeological study of the bridge site will cost $215,000 and include photographing and documenting artifacts, which will then be sent to the Virginia Department of Historic Resources in Richmond.

The bridge will cost about $31.4 million, and VDOT plans to begin construction in late fall of this year and complete construction in late 2008.

Md. finishes FEIS for Connector

The Maryland State Highway Administration and the Federal Highway Administration recently completed the Final Environmental Impact Statement (FEIS) for the Intercounty Connector (ICC), a proposed highway in Prince George’s and Montgomery counties. The comprehensive document is available on the Internet for viewing and download at www.iccstudy.org.

“Governor Ehrlich promised to break ground on the ICC before the end of 2006, and we are on track to fulfill that promise,” said Transportation Secretary Robert L. Flanagan. “The ICC will enhance mobility, safety, quality of life and economic development while successfully including environmental stewardship and enhancements.”

Since the publication of the Draft Environmental Impact Statement in November 2004, the ICC Study Team received and reviewed more than 3,800 pieces of correspondence and testimonies from citizens, elected officials and state and federal agencies. Based on agency and public comments, the ICC team refined and reduced community, cultural, wetland, stream and park impacts.

The team replaced eight acres of parkland for every acre affected by the ICC, though only required to create a one-to-one replacement. The team made changes to the project to require less land. The team also decided to use advanced and redundant erosion- and sediment-control practices during construction to contain mud in the construction site and out of waterways. A new storm-water management system in the medians and along the roadsides should reduce the size and amount of traditional ponds.

The FEIS will be available for public review until Feb. 27, after which the record of decision will be issued.

The proposed $2.4 billion ICC is a six-lane, multimodal, 18-mile highway connecting existing and planned development areas between I-270 in central Montgomery County and the I-95/U.S. 1 corridor in northwestern Prince George’s County.

Five for Wagman

G.A. & F.C. Wagman of York, Pa., received its fifth contract at the Woodrow Wilson Bridge Project in mid-January. The Maryland State Highway Administration awarded Wagman a $59.5 million contract to construct portions of the Washington, D.C., Beltway and the MD 210 Interchange.

Wagman has received five separate contracts, totaling over $260 million, for the Woodrow Wilson Bridge replacement project.

Construction for this most recent contract is expected to begin immediately and end in September 2008.

Mexico, U.S. seek cement agreement

The U.S. Commerce Department announced in mid-January its final results in the 14th administrative review of the antidumping order on gray portland cement from Mexico. Commerce calculated a dumping margin of 42% on imports of cement from August 2003 to July 2004.

“What this means is that the Mexican producers charged prices to its customers in Mexico that were 42% higher than it charged its customers in the U.S.,” said Joe Dorn, spokesman for the Southern Tier Cement Committee (STCC).

Commerce issued the antidumping order in August 1990, following findings that cement from Mexico was being sold at dumped prices in the southern tier of the U.S. and by the U.S. International Trade Commission that the dumped imports had materially injured U.S. cement producers and their workers.

In each year since the antidumping order, Commerce has conducted an administrative review to update the dumping margin calculation. Commerce has completed 14 administrative reviews, in which it has determined dumping margins ranging from a high of 109% to a low of 37%.

The root cause of the long-lived dumping problem is the closed Mexican cement market. Mexico imports virtually no cement. This allows Mexican producers to receive among the highest prices in the world for cement sold in Mexico, where per capita income ranks 80th in the world. They use high prices and profits received on sales in Mexico to subsidize their exports to the U.S. and to undersell U.S. producers, threatening domestic production and thousands of American jobs.

A striking example of Mexico’s protectionism is the Mary Nour, a vessel that was prevented from offloading a single shipment of cement from Russia into Mexico. After trying for a year to obtain authority from the Mexican government to offload at two Mexican ports, the ship was forced instead to sail for Africa. While Mexico blocks cement imports, the U.S. has the most open cement market in the world. In 2004, the U.S. received over 26 million metric tons of cement imports from over 30 countries.

The STCC has been working with the U.S. government for many years to see whether an acceptable settlement of the cement dispute can be negotiated with Mexico. A major issue is whether the Mexican government will give the U.S. and other foreign producers meaningful access to the closed Mexican market.

Currently, the STCC is working with Commerce in support of the department’s negotiations for a bilateral agreement with Mexico. The potential agreement would sharply reduce the existing tariffs, would prevent a surge of Mexican cement imports in the southern U.S. and would open up the Mexican markets to imports.

Sponsored Recommendations

The Science Behind Sustainable Concrete Sealing Solutions

Extend the lifespan and durability of any concrete. PoreShield is a USDA BioPreferred product and is approved for residential, commercial, and industrial use. It works great above...

Proven Concrete Protection That’s Safe & Sustainable

Real-life DOT field tests and university researchers have found that PoreShieldTM lasts for 10+ years and extends the life of concrete.

Revolutionizing Concrete Protection - A Sustainable Solution for Lasting Durability

The concrete at the Indiana State Fairgrounds & Event Center is subject to several potential sources of damage including livestock biowaste, food/beverage waste, and freeze/thaw...

The Future of Concrete Preservation

PoreShield is a cost-effective, nontoxic alternative to traditional concrete sealers. It works differently, absorbing deep into the concrete pores to block damage from salt ions...