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Prefabricated Modular Steel Bridges Provide Rapid, Reliable Solution to Restore Infrastructure in the Wake of Disasters

By Eugene Sobecki, Director National Sales and Military Business Development, Acrow Bridge

Transportation infrastructure is particularly vulnerable to the impacts of natural disasters, and climate change is expected to intensify future risks. Events such as hurricanes, flooding, and wildfires can disrupt accessibility to essential services such as education or healthcare and create business interruptions or delays that can cause long-term economic impact. Aside from natural disasters, transportation is also susceptible to man-made events such as accidents or terrorist attacks. 

In the aftermath of any significant disaster, it is the transportation infrastructure that underpins the restoration of all critical infrastructure components. When creating and restoring transportation lifelines quickly is crucial, prefabricated modular steel bridging can provide an ideal solution. 

For emergency applications, modular bridges have a number of distinct advantages over more traditional bridge types. Manufacturers have inventory of prefabricated components along with a supply network which allows for fast turnaround of materials. Damaged roads may make transporting heavy construction machinery, a prefabricated concrete structure or the length of a long steel beam structure unsafe or impossible. In contrast, modular steel bridging components can be transported in compact, easily maneuverable trucks and installed with minimal construction equipment. Modular steel structures can often be installed in extremely tight work areas, which may have resulted from the precipitating event. Finally, the speed to erect a modular steel span of any length can be counted in days or weeks rather than months or years. 

Every project comes with unique challenges, including the following modular bridge examples.

I-95 Oil Tanker Accident, Bridgeport, Connecticut

In March 2004, a tanker truck was involved in an accident on an elevated portion of the highway, which resulted in an explosion of some of the 9,000 gallons of heating fuel it carried. Both directions of the route in the vicinity were closed immediately and early reports indicated it would be weeks before the southbound overpass could open to traffic on the busiest highway in the Northeast and the major commercial route from Boston to New York. 

While overpass supports in both directions were damaged, inspection of the northbound bridge indicated it could be secured with reinforcing piers and it was re-opened to traffic in three days. The southbound bridge was not salvageable; it was immediately demolished, and after considering many options, it was decided to use a modular bridge as a detour during reconstruction.

Two days after the accident, workers began to construct the foundation and pour the concrete footings for the temporary bridge. The bridge was installed, paved and three lanes reopened to traffic less than a week after the crash.

I-10 Twin Span Bridge Hurricane Damage, Lake Pontchartrain, Louisiana

Just 11 days after Hurricane Katrina hit the region in late August 2005, competitive bids were requested to restore passage on the heavily damaged twin spans of Interstate 10, a major artery connecting New Orleans and Slidell. 

Upon inspection, the eastbound span was found to have the least number of damaged segments, so it was repaired with undamaged segments from the westbound side. Limited passage was restored within two weeks, more than two weeks ahead of schedule.

With much of the westbound span missing segments from the initial storm damage or used to repair the eastbound route, prefabricated modular steel components were utilized to provide another rapid solution to getting residents back to normal. The bridge was opened to traffic in late December, once again ahead of schedule.

US Route 85 Overpass Collapse, Lusk, Wyoming

In early June 2015, heavy rains caused the flooding of the Niobrara River which led to the collapse of an overpass on U.S. Route 85 onto railroad tracks below, creating an immediate stop to the passage of Union Pacific Railroad freight trains as well as vehicular traffic on the highway, which is the main artery from both Interstates 80 and 25.

U.S. 85 bridge in Lusk, Wyoming

As Wyoming DOT keeps an inventory of modular bridging components, they were quickly mobilized to the site, while additional components were purchased for the specifications of this very long span. The bridge was opened on July 25, 2015, restoring freight service and vehicular access.

Skagit River Bridge Collapse, Burlington, Washington

When an over-height tractor-trailer hit the I-5 bridge over the Skagit River in Burlington, Washington, in May 2013, the impact caused an entire 160-foot-long segment to plunge into the water, along with the truck and two cars. 

I-5 Skagit River Bridge in Burlington, Washington

Fortunately, there was no loss of life, but the financial impact caused by the loss of the vital crossing illustrated the need for a swift solution, and it was determined the installation of a detour structure was critical until repairs could be made to the damaged bridge.  

Two 24-foot-wide by 160-foot-span bridges were designed and installed and formally opened just 24 days after the collapse; they remained in place for four months until repairs were completed. 

Hurricane Maria, Puerto Rico

In assessing Hurricane Maria’s destruction across Puerto Rico in 2017, it was found that nearly 400 of the 2,344 bridges in the inventory of the Puerto Rico Highway and Transportation Agency were damaged, with 26 having collapsed outright. Providing survivors with urgently needed supplies and opening up routes for medical care was the first priority, with a larger goal the return to a pre-storm “normal” and reestablishing local commerce.

PR-957 in Palma Sola, Puerto Rico

As many of the impacted structures were in remote, mountainous regions with roads compromised by the storm, transporting materials to the work sites was far less difficult with compact, modular components requiring no heavy machinery for installation.  

The restoration of each crossing immediately allowed for safe passage of relief efforts from federal and state agencies. Children and support staff were able to return to school and employees to jobs. Most importantly, perhaps, each bridge reconnected vulnerable communities and helped countless Puerto Ricans return to routine life.  

Midwest Flooding 

The flooding in the Midwestern United States, beginning in early March 2019, caused devastating long-term damage across six states. In addition to the humanitarian need to restore damaged infrastructure as quickly as possible was the certainty of continued economic losses until mobility was restored. 

U.S. 136 in Rock Port, Missouri

Railroad freight in Rock Port, Missouri, was acutely impacted when a bridge providing the only access for crews to service equipment was closed due to sever scour to the structure’s supports. In order to expedite the restoration of full freight service in the region, a modular steel bridge was “overbridged” inside the existing structure to remove stress. The detour was opened to traffic eight days after the receipt of the order.

In northeast Nebraska, NDOT deemed detours necessary for two projects in the Spencer Dam/Niobrara River area. At each location, residents and first responders had been experiencing lengthy detours due to impassible crossings which would continue until construction was complete on new permanent bridges. Modular steel bridging enabled delivery to the work sites over compromised roads, and rapid design, delivery and installation provided solutions to transportation emergencies. 

U.S. 281 in Spencer, Nebraska

Shipping of components for each project began in early July and the first bridge was opened on July 29, 2019, ahead of schedule. The second bridge opened on schedule on August 13.

Damaged transportation assets represent a sizable portion of economic losses from disasters. Restoring damaged routes quickly can minimize the impact caused by business interruptions and freight inventory delays as well as impacts to the public at large.

Emergency bridging allows a fixed-dollar solution to the project whether rented or purchased; in the case of a purchased structure, it can be easily disassembled and warehoused for later use during planned projects or in an emergency situation.  

There is no doubt that disasters will continue to impact lives across, and the restoration of means of transportation will always be a priority. When disaster strikes, a modular steel bridge should be an option to consider.

This feature appeared in the November issues of the ACP Magazines: California Builder & Engineer, Construction, Construction Digest, Construction News, Constructioneer, Dixie Contractor, Michigan Contractor & Builder, Midwest Contractor, New England Construction, Pacific Builder & Engineer, Rocky Mountain Construction, Texas Contractor,
Western Builder

Acrow Bridge Provides Temporary Bridge and Lift Span to Speed Replacement of Bridge that Connects Palm Beach and West Palm Beach

Acrow Bridge Provides Temporary Bridge and Lift Span to Speed Replacement of Bridge that Connects Palm Beach and West Palm Beach

Avoids the need for lengthy disruption of road and water traffic at key crossing

Acrow Bridge, a leading international bridge engineering, and supply company provided a temporary lift bridge over the Intracoastal Waterway and Lake Worth Lagoon that helped avoid serious disruption to both road and water traffic there. The temporary bridge on Southern Boulevard connects the Town of Palm Beach at the Mar a Lago Club and the City of West Palm Beach. It is expected to be in place until completion of the project, now estimated for early winter 2020.

When structural problems were found with the existing bascule bridge, it was determined that a new structure was needed, including a temporary lift span during the lengthy construction to accommodate heavy vehicle traffic on the roadway as well as commercial and recreational vessel travel in the waterway below.

The lift span purchased from Acrow is 51.8 meters (170 feet) long with a roadway width of 9.2 meters (30 feet) and a 5 foot wide cantilevered footwalk. It uses four 75 foot (22.9 meters)towers and a 175 foot (53.3 meters) gantry system located on top of the towers. The structure is designed for an AASHTO HL-93 loading. It was particularly important when planning the detour that the temporary structure has superior structural strength, reliability, and durability as the bridge is required to be lifted every 30 minutes for vessel passage.

Scott Patterson, VP Engineering of Acrow Bridge said, “Lift bridges always pose technical challenges and there were many steps involved in the planned installation of the temporary bridge, requiring close coordination between Acrow’s mechanical, structural and electrical team members and the contractor. The lift span, towers, and machinery span were all assembled from Acrow truss panel components on-site and nearby. Large cranes were then used to lift them into place. Additionally, the tower top cross-beams and mechanical systems were installed using a crane.”

Added Acrow CEO Bill Killeen, “Like many other Acrow projects, the Southern Boulevard project’s ultimate success in terms of safety and cost efficiency involves the use of a long-term detour structure that eliminates disruption to the communities around it. We are pleased to have worked closely with the Florida Department of Transportation and its contractor on this important project.”

The project contractor is Johnson Brothers, a division of Southland Holdings, and the project owner is the Florida Department of Transportation. The design engineer is AECOM Technical Services of Tampa.

About Acrow Bridge

Acrow Bridge has been serving the transportation and construction industries for more than 60 years with a full line of modular steel bridging solutions for vehicle, rail, military and pedestrian use. Acrow’s extensive international presence includes its leadership in the development and implementation of bridge infrastructure projects in over 80 countries, covering Africa, Asia, the Americas, Europe and the Middle East. For more information, please visit www.acrow.com