Common Types of Bridges
Bridges are designed in many styles, each tailored to meet specific requirements based on the terrain, span length, available materials, and anticipated traffic load. Each bridge type's distinct design is determined by its particular advantages and the challenges presented by its location and intended function.
The most common types of bridges include, but are not limited to, the following:
- Beam Bridge: This is the simplest form of bridge, consisting of horizontal beams supported at each end by piers.
- Truss Bridge: This type of bridge is composed of a structure of connected elements forming triangular units. Truss bridges are very strong and can span large distances; they're often used for railroad and highway bridges.
- Arch Bridge: This type of bridge is identified by its arched shape, which supports the bridge by distributing weight into the supports at either end. The arch design can carry much weight and span large distances.
- Suspension Bridge: This architectural design is characterized by cables draped between towers, with vertical suspender cables supporting the weight of the deck below. This design facilitates particularly large distances.
- Cable-Stayed Bridge: Similar to the suspension bridge, the cables run directly from the towers to the roadway. This design allows for a more streamlined construction and can span long distances with fewer materials.
- Cantilever Bridge: This type of bridge is constructed using cantilevers, structures that project into space and are supported on only one end. It is used for spans where center supports are not feasible, such as over a body of water.
- Tied-Arch Bridge: An arch bridge in which the arch is not self-supporting but is strengthened by tensioned cables or rods in the deck structure. This allows for the bridge to span greater distances.
- Floating Bridge: Also known as a pontoon bridge, it consists of floating supports under the bridge deck. These bridges are typically temporary and used in calm bodies of water.
- Moveable Bridge: This category includes several types of bridges, such as drawbridges, bascule bridges, and swing bridges. They are designed to move to allow the passage of boats or other forms of transportation on the water below.
What Causes a Bridge to Collapse?
While relatively rare, bridge collapses are catastrophic events that highlight the importance of robust engineering, regular maintenance, and vigilant monitoring. Common causes of bridge failures can be categorized into several key areas, including natural events, human error, and structural failures. We explain some of the most common below.
Bridge Scour
Bridge scour is a predominant cause of bridge failures, characterized by removing sediment, such as sand and rocks, from around bridge abutments or piers. Scour occurs mainly due to moving water around the foundations, which can be exacerbated by weather events, natural water flow in rivers or bays, and flooding. This phenomenon can undermine the stability of a bridge, leading to partial or total collapse if the erosion progresses. Effective countermeasures include the design of scour-resistant bridge foundations, regular monitoring of water flow patterns, and the installation of protective structures around piers to reduce the velocity of water hitting the bridge's foundation.
Overloading
Bridges are engineered to bear specific load limits, which account for the weight of the bridge itself, vehicles, pedestrians, and even environmental loads like snow and ice. Overloading occurs when the weight on the bridge surpasses these predetermined limits, placing excessive stress on structural components. This overburden can lead to catastrophic failure, emphasizing the necessity for strict regulation of vehicle weights and the importance of considering changing environmental conditions in bridge design to accommodate potential increases in load due to climate change.
Material Fatigue & Corrosion
The durability of bridge materials is finite. Material fatigue refers to the weakening of materials from repeated stress and strain over time, leading to cracks and eventual failure. Concurrently, corrosion can further compromise the bridge's structural integrity. These processes are insidious, often occurring out of sight and gradually weakening structures to the point of failure. Prevention strategies include using corrosion-resistant materials, applying protective coatings, and regular maintenance to identify and address early signs of wear and tear.
Construction Errors
Errors during the construction phase can have lasting impacts on a bridge's integrity. Incorrect installation of components, reliance on substandard materials, or deviations from the design specifications can introduce weaknesses from the outset. Such mistakes underscore the critical need for stringent quality control measures throughout the construction process, qualified personnel, and adherence to design specifications to prevent future failures.
Insufficient Maintenance
Regular inspection and maintenance are pivotal in identifying and mitigating wear and tear before they evolve into significant problems. Insufficient maintenance can lead to the deterioration of key structural elements, allowing issues such as minor cracks, corrosion, or scour to progress to critical points. A proactive maintenance regime, including routine inspections and timely repairs, is essential for extending the lifespan of bridges and ensuring their safety.
Natural Disasters
The forces of nature—earthquakes, floods, hurricanes—pose significant risks to bridges. These events can induce immediate and severe damage through mechanisms like foundation scour from floodwaters or structural cracking from seismic activity. Designing bridges to withstand these forces involves incorporating flexibility, redundancy, and robustness into their design, adhering to updated building codes that account for the latest research and climate predictions, and implementing advanced materials and construction techniques.
Impact Damage
The impact from vehicles or boats striking a bridge can cause immediate and visible damage, as well as more subtle structural weaknesses that develop over time. Implementing barrier systems or pier protection is crucial, especially for bridges over navigable waterways or major roadways. These systems act as a sacrificial barrier to absorb and distribute impact forces, protecting the bridge's structural components from direct damage.
What Happens When There Is No Pier Protection?
The importance of pier protection systems in bridge safety cannot be overstated.
These systems act as a critical line of defense, designed to absorb and distribute the impact energy from vehicles or vessels, thereby safeguarding the bridge's support piers from direct damage. Such protective measures are particularly crucial for bridges over busy waterways or roadways, where the risk of collisions is heightened. Without adequate pier protection, bridges are significantly more vulnerable to structural damage in the event of an impact, which can lead to catastrophic failures, endangering human lives and causing major disruptions to transport and the economy.
Recent Bridge Collapses
The Francis Scott Key Bridge Collapse of 2024
Just after midnight on March 26, 2024, the Dali, a cargo ship owned by Singapore-based Grace Ocean Pte Ltd and operated by Synergy Marine Group leaving the Port of Baltimore, crashed into the Francis Scott Key Bridge, causing it to collapse into the Patapsco River below. The cause of the accident has not yet been determined, and as of the following afternoon, six construction workers were still unaccounted for and presumed dead. The bridge was open to traffic during the crash, and overnight construction was underway. Before its untimely collapse, the steel arch continuous truss bridge was the outermost crossing of the Baltimore harbor, providing an essential connection for Interstate 695.
The Fern Hollow Bridge Collapse of 2022
The NTSB identified crucial oversights in maintenance and regulatory compliance as key factors in the collapse of Pittsburgh's Fern Hollow Bridge on January 28, 2022, which resulted in injuries to four individuals when the structure plummeted approximately 100 feet with six vehicles onboard. The following investigation revealed the collapse was initiated by a corroded transverse tie plate, exacerbated by water and debris that prevented protective patina formation. Alleged negligence toward maintenance recommendations, alongside inadequate inspections and inaccurate load rating calculations, highlighted a broader failure of oversight across city, state, and federal levels. In response, the NTSB issued 11 new recommendations aimed at enhancing inspection and maintenance protocols for the Federal Highway Administration (FHWA), PennDOT, the City of Pittsburgh, and the American Association of State Highway and Transportation Officials, stressing the importance of rigorous infrastructure management to ensure public safety.
Who Is Responsible for Bridge Collapses?
Assigning responsibility for a bridge collapse is an intricate and multifaceted process, entailing extensive investigations and often complex legal battles. The blame for such devastating incidents can be distributed among various entities involved in the bridge's lifecycle, including its design, construction, upkeep, and day-to-day management. For those affected by bridge collapses, pinpointing where the responsibility lies is not only crucial for seeking justice and obtaining compensation but also plays a vital role in advocating for enhanced safety protocols and standards.
Determining accountability typically involves a comprehensive analysis of numerous factors, such as the adherence to design specifications, the quality of materials used, the execution of construction techniques, and the rigor of maintenance schedules, alongside a review of compliance with prevailing regulations and standards.
For victims and their families, identifying the parties at fault is a pivotal step toward compensation and closure. Moreover, rigorously addressing and highlighting the failures that led to the collapse makes it possible to impose necessary reforms. This not only ensures that those responsible are held accountable but also contributes significantly to the advancement of safer bridge design, construction, and maintenance methodologies in the future.
Contact a Bridge Collapse Lawyer Today: (888) 493-1629
A bridge collapse can be an incredibly traumatic event, leaving victims and their families to navigate a daunting aftermath of catastrophic injuries, emotional distress from the loss of a loved one, and financial uncertainty. If you or a loved one has suffered as a result of a bridge collapse, know that you’re not alone during this challenging time. A bridge collapse lawyer at Arnold & Itkin can help you navigate your next steps. We are known nationwide for being there to help in the aftermath of the nation's worst tragedies, including massive plant explosions, maritime disasters, and more. We have helped our clients recover more than $20 billion, setting records with our victories and helping our clients move forward with their lives. If you would like to discuss your case with a bridge collapse attorney you can trust, we encourage you to reach out to us today. Review our testimonials, check out our case results, and get to know us better.
Don’t hesitate to contact our bridge collapse lawyers at (888) 493-1629.
