Boh Bros. Construction Co. is part of the construction team building the new I-10 Twin Span Bridge after Hurricane Katrina badly damaged the existing structure.

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The state of Louisiana continues to rebuild infrastructure throughout the areas where hurricanes Katrina and Rita wreaked havoc in 2005. One of the largest efforts is the replacement of the Interstate 10 Twin Span Bridge , which is an $800 million contract currently under construction.

The Louisiana Department of Transportation (LDOT) awarded Boh Bros. a contract to construct four-and-a-half miles of the low-rise portions of the twin span bridge. Boh Bros. says its $375 million portion of the contract is the largest public works contract ever let by LDOT and the largest contract ever awarded to the company.

Boh Bros. says it is constructing two new bridges 300 feet east of the current spans. Each bridge will consist of three traffic lanes and two 12-foot shoulders. The company also says the bridge will rest 30 feet above Lake Pontchartrain, and that the high-performance, high-strength concrete on the bridge will be more resistant to salt water corrosion. LDOT says the new bridge will be 21 feet higher than the existing Twin Span Bridge.

Boh Bros. is building the level portion and the approaches for the new bridge, according to LDOT. This work includes pile driving, placing pile caps, placing girders laying the roadway decks and pouring retraining walls. The company says the completion of the eastbound and westbound bridge is schedule for 2011.

As of February 2008, crews had driven 1,820 of the 3,256 concrete piles that will be needed for the new bridge. The piles are driven at bent locations, and then topped with concrete bent caps, LDOT says.

“The bent caps are then connected horizontally to the previous bent location by concrete girders,” the agency explains. “Forms constructed atop the girders are used to pour the concrete bridge decks that will ultimately support the roadway. The bridge decks are 135 feet long and weigh approximately 2 million pounds.

“Bridge building is a repetitive process performed in a manner that sometimes resembles an assembly line,” LDOT adds. “Plans are to have the first span of the new bridge ready for traffic in mid- to late-’09.”

Existing Bridge
Although the existing Twin Span Bridge sustained major damage during Hurricane Katrina, LDOT says it is still safe for travel and has instituted numerous maintenance and preventive safety initiatives to keep it so. LDOT says sections of the westbound bridge between Slidell and New Orleans, La., have been repaired using prefabricated metal bridge sections that require regular inspection and maintenance.

“Maintenance crews are on site seven days a week to ensure the safety of the bridge,” LDOT says. “Motorists are advised to obey the speed and weight limits for the bridge. Speeding and overweight vehicles can do damage to the prefabricated metal bridge sections.”

LDOT also implements lane closures because it says the prefabricated metal panels require regular inspection and maintenance to ensure the continued safety of the bridge. However, this work must be done during the day so inspectors have enough light to adequately inspect the bridge components.

“The inspections usually require closure of one lane at a time,” LDOT says. “When repairs are needed, it is sometimes necessary to close both lanes. Whenever possible, these full closures are limited to overnight hours.”

Also, LDOT states that it is using specially designed jacks beneath the existing bridge that are capable of supporting 25 tons each. They are used in locations where the existing bearings sustained 25 to 40 percent damage, it adds.

“The concrete bearings are still supporting much of the weight, with the jacks enhancing safety by providing a redundant measure of support,” LDOT says.

‘Thousands of Man-Years’
Boh Bros. was founded in 1909 when Arthur P. Boh undertook his first construction project, the building of four duplexes in a New Orleans neighborhood. His brother, Henry, joined the company in 1913, which led to the name it has today, according to the company.

Today, Boh Bros. has expanded to include Texas to its west and Mississippi, Alabama, Florida and Georgia to its east. It keeps its headquarters in New Orleans and has permanent offices in Baton Rouge, La., and Mobile, Ala.

The company says it contracts several hundred projects per year and the annual volume is in excess of $250 million. Boh Bros. works in industrial and commercial projects, asphalt and concrete paving, mechanical and industrial piping, marine construction and dock work, bridges, highway and heavy construction, excavation and site development, and railroads.

“Like most successful companies, Boh Bros. attributes its success to its people and the accumulated skills and expertise of thousands of man-years of service,” the company says. “Additionally, the company has been able to maintain a strong financial base and to acquire and operate a fleet of modern, well-maintained equipment.”