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The Homestead Grays Bridge underwent an extensive rehabilitation that included widening the roadways and replacing the decks to removing the lead paint and repainting the structure. Keeping the bridge open for two lanes of traffic during the project required the use of three construction phases that involved shifting lanes as the project progressed.

The strategy for a seismic retrofit of the historic Bixby Bridge in Big Sur, California is presented. Topics addressed include computer modelling of the bridge's seismic vulnerability, retrofit designs that are visually unobstrusive, and techniques and materials used to strengthen the structure.

The reconstruction of bridges while allowing traffic provides the engineers with extra problems. Major part of the construction work is done during night time to avoid the problems. The reconstruction of Baltimore Hanover Street Bridge, Providence Viaduct, Verrazano Narrows Bridge and South Tenth Street Bridge, in eastern US, while open to traffic are discussed.

The designs for the reconstruction of bridges by the Caltrans in the earthquake-affected Los Angeles city, CA, are assessed by the peer review panel (PRP). The PRP is constituted by university professors and professional engineers who evaluate the steel-cladding retrofit for viaducts. Non-structural features and edge-beam processes are some of the issues reviewed by the panel.

Engineers from the Pavlo Engineering Co., New York, engaged by the officials of Cuyahoga Country, Ohio, were involved in the rehabilitation of Cleveland's Main Avenue Bridge. They were given the construction contract by the Ohio Department of Transportation and Howard Needles Tammen & Bergendoff, Cleveland, who were asked to design detour routing for traffic during construction. They got together a value engineering task force and adopted a proactive approach to traffic management.

Florida Department of Transportation officials faced the task of demolishing the Sunshine Skyway Bridge following an accident which damaged the structure. The project's first phase involved dismantling the main piers, deck and structural steel. The demolition phase included lowering the main span using a special rig with cables. Then, steel trusses were cut with the use of explosives which detonate on a small area and burn through the steel. Cranes served to detach the concrete beams. Meanwhile, workers demolished the concrete piers with explosives and took them below the waterline.

New York, NY-based engineering firm Steinman Boynton Gronquist and Birdsall conducted a state-of-the-art evaluation of Williamsburg Bridge in New York City. Results of the study led to proposals to replace the old deck with a novel steel orthotropic deck mounted to the floor girders. The system improves the load-carrying capability of the bridge because of their lightweight and ability to combine with the superstructure. It also minimizes corrosion and increases the economic life span of the bride because of the lesser number of joints required.

The 850 ft arched truss bridge over Grand River in Cleveland underwent a midair repair scheme because the bridge's thick gusset plates were damaged. The repair was conducted by attaching jacking brackets to the lower chords of the failed joint and to strain gauge members. The strain gauge members were realigned through post-tensioning so that partial replacement gussets could be positioned. Although the repair of the damaged part of the bridge was complicated, it was completed in five-months time.

The Bonner Bridge in North Carolina is scheduled for repair after more than 30 years of withstanding the harsh effects of hurricanes and northeasters. Parsons Brinckerhoff Quade & Douglas Inc was commissioned to provide the complete plan of the bridge's replacement. Computer and physical models were used to analyze scour, help engineers design a better bridge and reduce construction expenditures.

Bridge engineers need to pay closer attention to the effects of wear and tear on their projects, as failure to do so can result in grave mishaps.Many errors are committed by young engineers because of their preoccupation with the mechanics of design and plan preparation and lack of attention to the structure itself. A lack of visualization skills, ignorance about the effects of metal fatigue and other limitations of the new engineers are also the contributing factors.

The new approach adopted by Alabama DOT to repair its interstate-highway structures, wherein inspections and repair are performed simultaneously, has replaced the traditional approach to inspections, design and construction in a sequential order in bridge-repair work. This method is versatile in repairing concrete and difficult-access bridges by saving time through better engineer-contractor relations in performing emergency and various other forms of repairs.

Attention has always been focussed on long term bridges, but short span bridges, which are in a bad condition, are usually neglected. These small bridges, 25 feet long and found in rural county areas, need care according to a US Dot survey. They are marred by age, corrosion, increasing traffic and excess loads. Buried culverts are the most significant change among many suggested changes for short span bridges. These culverts are easier to design and construct, need less finance and resist bridge deck-icing and deterioration.

A precast-concrete deck system is keeping the Tappan Zee Bridge open despite undergoing a major repair. The project involves replacement of bridge decks with precast-concrete. Description and duration of the project are also mentioned.

The Minnesota Department of Transportation's bridge inspection program discovered gusset plate problems on the DeSoto bridge prompting them to close the bridge as a precaution. The John A. Blatnik bridge was also discovered to have the same problems a few weeks after the closure of the DeSoto bridge. The DeSoto Bridge will be replaced while the gusset plates on the Blatnik bridge will be repaired.

The combination of digital imaging and mapping techniques with a mechnical rock-scaling process, for the completion of highway remediation on the Interstate 90 in the state of Washington, is described.

Rochester city and New York's Department of Transportation (DOT) have decided to replace the 50-year-old Troup Howell Bridge in Rochester, New York. The bridge has been suffering from problems since its construction.

The Shelby Street Bridge in Nashville designed was a time-tested element, such as the metal trusses and concrete T beams, and a daring, one-of-a-kind concrete truss is facing from an identity crisis. Efforts are being made to repair and relocate steel trusses, replacing deteriorating approach spans, and thus serving a necessary function and also is a jewel in the cityscape of Nashville.

Earthquake damage to bridges can be prevented by wrapping bridge columns with continuous carbon-fiber composites. Carbon-composite retrofit wrappings are two to four times stronger than existing steel jackets while installation is less labor-intensive and require less lane closure and traffic control. These wrappings are also corrosion-resistant and are invulnerable to the effects of water and alkali.

The Massachusetts Highway Department is using the Integrated Bridge Inspection Information System (IBIIS), a multimedia information system, for the maintenance of at least 5,000 bridges under its responsibility. IBIIS allows engineers to conveniently collect, store, retrieve and distribute bridge inspection data. Document management problems are solved with the integration of data compression/decompression technologies and desktop scanning equipment to store photographs on the IBIIS.

The United States Federal Highway Administration has started a program focused on highway bridges. The program will collect data and create a database that could be used to create better deterioration and life-cycle cost models. Other details of the program are also discussed.

Work to rehabilitate the deck of the Brooklyn Bridge has been accelerated with construction crews working each night to replace the deck before it reaches the end of its useful life. The 34-million project requires the workers to conduct activities on platforms suspended beneath the bridge while replacing 60-ft long sections of the 1,596-ft main span each evening. About 400 cracked floor beams will be replaced, aside from other repairs. The crews are being provided a $45,000 per night incentive for early completion of the deck.

Officials of the Federal Highway Administration and from the transportation sector are in Europe to study scour countermeasures at bridges and flood control structures. They found that scour is not a problem for the public works in Germany, Switzerland and the Netherlands since countermeasures are included in their designs. The UK as well as the US retrofits their existing infrastructure with scour countermeasures. They have also discovered that their European counterparts make extensive use of ripraps or stones in combination with geotextiles or granular filters.

The San Diego-Coronado Bay Bridge in California is undergoing a seismic upgrade program. The $95 million project, which was designed by the California Dept of Transportation, T.Y. Lin International/McDaniel and J. Muller International, focuses on the strengthening of piers and addition of seismic isolator equipment. Engineers will place 200 to 400 mm post-tensioned reinforced concrete to pier caps. They will also encase the piers with concrete that extends 8.5 m down from the retrofitted caps.

Many bridges on the list of physically obsolete bridges can be renovated using aluminum decks. The renovations cut dead load and increase the permissible vehicle weight substantially. The technique, which involves replacement of existing steel panels by prefabricated aluminum deck panels, is both cost and time efficient. Testing of the redecked bridge is done by measuring the impact of cyclic and static loading in the field and laboratory. This technique has been put to use at the Corbin Bridge, near Altoona, Pa., and at a bridge at Buffalo Creek in Virginia.

An excellent protection against corrosion is provided by the epoxy coatings and concrete combination of the bridges in Indiana even 18 years after their construction despite questions about the epoxy's value. These types of bridges show long-term performance against a severe chloride environment. The chloride concentration is much higher than the threshold value in the level of reinforcement of the bridges. The result of the study performed with the seven bridges in Indiana reveals that the chloride content decreases with the increase in concrete cover, disbondment of the coating is absent in the reinforcement.

The rehabilitation of the Riva Road Bridge in Annapolis, MD, involved a performance-based contract with corresponding bonus-penalty clauses depending on whether McLean Contracting meets its stipulated construction deadlines. The project engineers used the 'lift-and-swap' method to install new prefabricated spans in place of the original ones. This served to maintain the use of the bridge even during construction. The bidding process reduced the rehabilitation project's projected cost.

Oregon began a campaign to save the rest of its bridges from the ravages of rebar corrosion after the public outcry elicited from the demolition of the Alsea Bay Bridge. This comprehensive program of corrosion preventing the Yaquina Bay Bridge is also seen as good investment. Difficulties were encountered when the upper layer had to be stripped. Jackhammer drilling posed the threat of microcracking due to the vibration of the grinder. An effective alternative used is the process of hydrodemolition, wherein jets of water broke up concrete as it cleaned reinforcing bars to very precisely measured depths.