Glossary

6.5 Coastal bridges and roads

9 min read•august 21, 2024

Coastal bridges and roads are critical components of transportation infrastructure in coastal regions. They face unique challenges due to their exposure to harsh marine environments, including saltwater corrosion, erosion, and the impacts of and storm surges.

Designing resilient coastal transportation systems requires careful consideration of environmental factors, structural integrity, and long-term sustainability. This involves innovative engineering approaches, from material selection to adaptive design strategies, to ensure these vital links can withstand the dynamic coastal conditions they face.

Coastal transportation infrastructure

  • Coastal transportation infrastructure forms the backbone of connectivity in coastal regions, playing a crucial role in Coastal Resilience Engineering
  • Designing and maintaining these systems requires careful consideration of environmental factors, structural integrity, and long-term sustainability
  • Effective coastal infrastructure enhances community resilience by facilitating evacuation routes and supporting economic activities in coastal areas

Types of coastal bridges

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Top images from around the web for Types of coastal bridges

  • Causeway to Rough Island (11) © Albert Bridge :: Geograph Britain and Ireland View original

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  • Causeway to Rough Island (11) © Albert Bridge :: Geograph Britain and Ireland View original

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  • Fixed bridges span waterways and inlets, providing permanent connections between coastal landmasses
  • Movable bridges (bascule, swing, vertical lift) allow for marine traffic passage while maintaining road connectivity
  • Causeway bridges extend over long stretches of water, often incorporating multiple spans and artificial islands
  • Viaducts elevate roadways over low-lying coastal areas, protecting against flooding and storm surge
  • Pontoon bridges offer temporary or semi-permanent solutions for crossing coastal waters in certain situations

Road systems in coastal areas

  • Coastal highways run parallel to shorelines, serving as main arteries for regional transportation
  • raise the travel surface above flood levels, enhancing resilience to sea-level rise and storm events
  • Coastal access roads connect inland areas to beaches, ports, and coastal communities
  • Permeable pavements allow for better drainage and reduced runoff in flood-prone coastal zones
  • Traffic management systems incorporate real-time monitoring and adaptive routing during extreme weather events

Environmental impacts on infrastructure

  • Environmental factors significantly influence the longevity and performance of coastal transportation infrastructure
  • Understanding these impacts is essential for developing effective resilience strategies in Coastal Resilience Engineering
  • Proper design and maintenance practices can mitigate environmental damage and extend infrastructure lifespan

Effects of saltwater exposure

  • Chloride ion penetration accelerates corrosion of steel reinforcements in concrete structures
  • Salt crystallization causes spalling and deterioration of concrete surfaces
  • Electrical systems and metal components experience accelerated degradation due to salt-induced corrosion
  • Saltwater intrusion affects the soil properties beneath foundations, potentially leading to structural instability
  • Protective coatings and sealants require frequent reapplication to maintain effectiveness against salt exposure

Erosion and scouring processes

  • Wave action undermines bridge foundations and road embankments through continuous abrasion
  • Tidal currents create scour holes around bridge piers, compromising structural stability
  • Coastal storms intensify erosion rates, potentially exposing buried infrastructure components
  • Longshore drift alters shoreline configurations, affecting the placement and protection of coastal roads
  • patterns influence the accumulation of debris around infrastructure, requiring regular maintenance

Design considerations

  • Design considerations in Coastal Resilience Engineering focus on creating infrastructure that can withstand harsh coastal environments
  • Balancing structural integrity with environmental adaptation is crucial for long-term sustainability
  • Innovative design approaches incorporate flexibility to accommodate future climate change scenarios

Load-bearing capacity vs wave forces

  • Dynamic wave loading requires structures to withstand both vertical and horizontal forces
  • Wave impact forces can exceed static design loads, necessitating additional structural reinforcement
  • Hydrodynamic lift affects bridge decks during extreme storm events, requiring secure anchoring systems
  • Resonance frequencies of structures must be calculated to avoid amplification of wave-induced vibrations
  • systems help transfer wave forces throughout the structure, reducing localized stress points

Material selection for durability

  • Corrosion-resistant reinforcing steel (stainless steel, fiber-reinforced polymer) extends the lifespan of concrete structures
  • High-performance concrete mixtures incorporate additives to enhance durability and reduce permeability
  • Composite materials offer lightweight, high-strength alternatives to traditional construction materials
  • Elastomeric bearings and expansion joints accommodate movement while preventing water infiltration
  • Protective coatings (epoxy, polyurethane) provide additional barriers against saltwater intrusion and UV degradation

Resilience strategies

  • Resilience strategies in coastal infrastructure design aim to enhance adaptability and reduce vulnerability to environmental hazards
  • Implementing these strategies is a key focus of Coastal Resilience Engineering, ensuring long-term functionality of transportation systems
  • Effective resilience measures often combine structural and non-structural approaches to address multiple risk factors

Elevation and clearance requirements

  • Freeboard height accounts for projected sea-level rise and storm surge levels over the infrastructure's lifespan
  • Vertical clearance for bridges factors in potential increases in extreme wave heights due to climate change
  • Approach grades for elevated roadways balance accessibility with flood protection requirements
  • Clearance under bridges considers future changes in navigation needs and environmental conditions
  • Adaptive design allows for future elevation adjustments without major structural modifications

Protective structures for bridges

  • Scour protection systems (riprap, articulated concrete blocks) safeguard bridge foundations from erosion
  • redirect wave energy away from vulnerable bridge components
  • Fender systems absorb impact forces from vessel collisions, protecting bridge piers
  • Breakwaters and artificial reefs attenuate wave energy before it reaches bridge structures
  • Sacrificial elements (fuse plugs, shear keys) fail predictably during extreme events, protecting critical structural components

Maintenance and inspection

  • Regular maintenance and inspection are critical components of Coastal Resilience Engineering for transportation infrastructure
  • Proactive maintenance strategies help identify and address potential issues before they escalate into major problems
  • Advanced inspection technologies enable more accurate assessments of infrastructure condition in challenging coastal environments

Corrosion prevention techniques

  • use sacrificial anodes or impressed current to prevent reinforcement corrosion
  • Concrete sealers and penetrating corrosion inhibitors create barriers against chloride ion ingress
  • Galvanized or epoxy-coated reinforcement provides additional protection against corrosion initiation
  • Periodic washing and cleaning remove salt deposits from exposed surfaces, reducing corrosion risk
  • Dehumidification systems control moisture levels in enclosed bridge spaces, minimizing corrosion potential

Structural health monitoring systems

  • Embedded sensors (strain gauges, accelerometers) provide real-time data on structural performance
  • Acoustic emission monitoring detects early signs of concrete cracking and reinforcement corrosion
  • Fiber optic sensors measure temperature, strain, and displacement across large infrastructure spans
  • Corrosion potential mapping identifies areas of active corrosion within reinforced concrete elements
  • Data analytics and machine learning algorithms process monitoring data to predict maintenance needs

Adaptation to sea level rise

  • Adapting to sea level rise is a critical challenge in Coastal Resilience Engineering for transportation infrastructure
  • Long-term planning and flexible design approaches are essential to accommodate uncertain future scenarios
  • Adaptation strategies often involve a combination of physical modifications and policy changes

Flexible design approaches

  • allow for easier future modifications and upgrades
  • Incremental adaptation pathways incorporate staged implementation of resilience measures over time
  • Floating infrastructure concepts provide inherent adaptability to changing water levels
  • Sacrificial components designed to be replaced or upgraded as sea levels rise
  • Multi-functional designs serve transportation needs while incorporating flood protection features

Managed retreat options

  • Phased relocation plans for vulnerable coastal roads and bridges to higher ground
  • Land-use policies that discourage new development in high-risk coastal areas
  • Creation of buffer zones between infrastructure and shorelines to accommodate future retreat
  • Integration of green infrastructure (wetlands, dunes) to replace hard structures over time
  • Development of alternative transportation routes to maintain connectivity during managed retreat processes

Storm surge protection

  • Storm surge protection is a crucial aspect of Coastal Resilience Engineering for transportation infrastructure
  • Designing for extreme events requires consideration of both frequent and rare storm scenarios
  • Integrating surge protection measures with other infrastructure functions can enhance overall system resilience

Surge barriers for roads

  • Deployable flood barriers provide temporary protection for critical road sections during storm events
  • Raised road profiles act as levees, protecting inland areas while maintaining transportation function
  • Pumping stations and drainage systems manage water accumulation behind surge barriers
  • Floodgates at road entrances prevent water ingress while allowing controlled access when needed
  • Permeable road surfaces combined with subsurface storage reduce runoff and mitigate local flooding

Bridge pier reinforcement

  • Hydrodynamic shaping of bridge piers reduces drag forces from storm surge and waves
  • Pile cap extensions increase the stability of bridge foundations during scour events
  • Collars and riprap placement around piers provide additional protection against scour and erosion
  • Structural strengthening of pier connections to superstructures prevents uplift during extreme surge events
  • Sacrificial fender systems absorb impact forces from debris carried by storm surge

Ecological considerations

  • Ecological considerations are increasingly important in Coastal Resilience Engineering for transportation infrastructure
  • Balancing infrastructure needs with environmental protection enhances overall coastal ecosystem resilience
  • Integrating ecological features into infrastructure design can provide multiple benefits for both human and natural systems

Wildlife passage accommodations

  • and overpasses allow safe crossing for terrestrial species along coastal corridors
  • Culverts designed to maintain natural stream flow and facilitate aquatic organism passage
  • Light and noise reduction measures minimize disturbance to sensitive coastal wildlife habitats
  • Fencing and guidance systems direct animals towards safe crossing points
  • Monitoring programs assess the effectiveness of wildlife passages and inform adaptive management

Habitat preservation techniques

  • Artificial reef structures incorporated into bridge foundations provide habitat for marine organisms
  • (living shorelines) combine with habitat creation
  • Stormwater management systems that mimic natural processes and support local ecosystems
  • Timing of construction activities to avoid critical breeding and migration periods for coastal species
  • Compensatory mitigation projects that restore or enhance habitats affected by infrastructure development

Economic factors

  • Economic considerations play a crucial role in decision-making for coastal transportation infrastructure projects
  • Coastal Resilience Engineering must balance immediate costs with long-term benefits and risk reduction
  • Innovative financing mechanisms and partnerships are often necessary to fund large-scale resilience projects

Cost-benefit analysis of resilience measures

  • incorporate initial construction, maintenance, and potential damage costs
  • Quantification of indirect benefits (improved evacuation routes, economic continuity) in resilience calculations
  • Risk-based approaches that consider the probability and consequences of infrastructure failure
  • Ecosystem service valuation to account for environmental benefits of resilient infrastructure design
  • Scenario analysis to evaluate the cost-effectiveness of different resilience strategies under various climate projections

Funding sources for infrastructure upgrades

  • specifically targeted at coastal resilience and adaptation projects
  • State and local bond measures to finance large-scale infrastructure improvements
  • Public-private partnerships that leverage private sector investment in resilient infrastructure
  • Resilience fees or taxes applied to development in high-risk coastal areas to fund adaptation measures
  • International climate finance mechanisms supporting coastal infrastructure projects in developing countries

Case studies

  • Case studies provide valuable insights into the practical application of Coastal Resilience Engineering principles
  • Analyzing successful projects and lessons learned informs future infrastructure design and adaptation strategies
  • Diverse case studies demonstrate the range of approaches available for enhancing coastal transportation resilience

Successful coastal bridge projects

  • Confederation Bridge (Canada) incorporates ice protection and extreme weather design for harsh coastal conditions
  • Øresund Bridge (Denmark/Sweden) combines a bridge and tunnel system to minimize environmental impact
  • San Francisco-Oakland Bay Bridge (USA) retrofit included seismic upgrades and corrosion-resistant materials
  • Incheon Bridge (South Korea) features advanced structural health monitoring and wind resistance design
  • Donghai Bridge (China) utilizes precast concrete elements to accelerate construction in challenging marine environment

Road adaptation examples

  • Beach Road in Revere, Massachusetts (USA) elevated to protect against flooding and future sea-level rise
  • Pacific Coast Highway realignment in Big Sur, California (USA) to address chronic landslides and coastal erosion
  • A1A Highway in Fort Lauderdale, Florida (USA) reconstructed with a seawall and dune system for storm protection
  • Great Ocean Road in Victoria (Australia) implemented managed retreat strategies for vulnerable coastal sections
  • Kopu Bridge replacement in New Zealand incorporated climate change projections and improved flood resilience
  • Future trends in Coastal Resilience Engineering focus on innovative solutions to address evolving challenges
  • Integration of advanced technologies and materials enhances the adaptive capacity of coastal infrastructure
  • Holistic approaches that combine engineering, ecology, and social factors shape the future of coastal transportation systems

Innovative materials in construction

  • Ultra-high performance concrete (UHPC) offers superior strength and durability for coastal applications
  • Self-healing concrete incorporates bacteria or polymers to automatically repair small cracks
  • Carbon fiber reinforced polymers (CFRP) provide lightweight, corrosion-resistant alternatives to steel reinforcement
  • Geosynthetics enhance soil stabilization and erosion control in coastal environments
  • Biomimetic materials inspired by marine organisms improve resistance to biofouling and corrosion

Smart infrastructure technologies

  • Internet of Things (IoT) sensors enable real-time monitoring and predictive maintenance of coastal infrastructure
  • Artificial intelligence and machine learning algorithms optimize traffic flow and infrastructure performance
  • Augmented reality systems assist in infrastructure inspection and maintenance procedures
  • Autonomous vehicles and smart road systems enhance safety and efficiency in coastal transportation
  • Digital twin technology creates virtual models of infrastructure for improved planning and risk assessment

Key Terms to Review (26)

Bioengineered shoreline stabilization methods: Bioengineered shoreline stabilization methods are environmentally friendly techniques that use living plant materials and natural processes to enhance the stability of coastlines while protecting against erosion. These methods combine traditional engineering practices with ecological principles, aiming to restore natural habitats and promote biodiversity while effectively managing coastal erosion and wave impacts.
Cathodic protection systems: Cathodic protection systems are techniques used to prevent corrosion of metal surfaces, particularly those in contact with water or soil, by making them the cathode of an electrochemical cell. This method is essential for preserving the structural integrity of coastal infrastructure like bridges and roads, which face harsh environmental conditions. By reducing the rate of corrosion, these systems can significantly extend the lifespan of metal structures and reduce maintenance costs.
Coastal zone management policies: Coastal zone management policies are regulatory frameworks and strategies designed to manage and protect coastal areas from the impacts of human activity and natural processes. These policies aim to balance development, environmental protection, and community resilience by addressing issues such as habitat conservation, land use planning, and disaster risk management.
Elevated roadways: Elevated roadways are roads or highways that are raised above the ground level, often supported by columns or pylons. These structures are designed to minimize the impact of flooding, reduce traffic congestion, and improve transportation efficiency in coastal areas that are vulnerable to sea-level rise and storm surges.
Erosion control: Erosion control refers to methods and practices aimed at preventing or minimizing the loss of soil and land due to wind, water, or human activity. This is crucial in protecting coastal areas from degradation, preserving habitats, and maintaining infrastructure integrity. Effective erosion control strategies are essential in the context of coastal management, as they help mitigate the impacts of natural events and human activities on shoreline stability and environmental health.
Federal grant programs: Federal grant programs are financial assistance initiatives established by the U.S. government to provide funding for specific projects or activities that serve public interests. These programs are vital for supporting various sectors, including transportation, education, and environmental protection, by facilitating the development and maintenance of essential infrastructure such as coastal bridges and roads.
Flexible bridge design: Flexible bridge design refers to the architectural and engineering approach that emphasizes adaptability and resilience in the construction of bridges, allowing them to better respond to environmental forces such as wind, waves, and seismic activities. This design philosophy is especially crucial for coastal bridges, where factors like shifting tides, storm surges, and the corrosive effects of saltwater are prevalent. By incorporating flexibility into the structural design, these bridges can enhance safety, durability, and longevity while minimizing damage during extreme weather events.
Flood-proofing techniques: Flood-proofing techniques are measures designed to prevent or mitigate the impact of flooding on structures, particularly in areas prone to high water levels. These strategies can involve elevating buildings, using water-resistant materials, and implementing barriers to redirect floodwaters, all of which are essential for protecting coastal bridges and roads from damage during extreme weather events.
Floodplain regulations: Floodplain regulations are legal frameworks designed to manage land use and development in flood-prone areas, aiming to minimize flood risk and protect both the environment and public safety. These regulations typically involve restrictions on construction, requirements for flood-resistant design, and guidelines for land management practices, all of which help reduce the impacts of flooding on communities and infrastructure, especially in coastal regions.
Geographic Information Systems (GIS): Geographic Information Systems (GIS) are computer-based systems that allow for the capture, storage, analysis, and visualization of spatial and geographic data. These systems enable users to understand relationships, patterns, and trends in data related to geographical locations, making them crucial for planning and decision-making processes across various fields.
Hydrodynamic forces: Hydrodynamic forces are the forces exerted by moving water on objects, such as structures and surfaces, due to the interaction between water flow and these objects. These forces play a crucial role in the design and stability of coastal infrastructure like bridges and roads, as they can significantly affect their structural integrity and functionality during events like storms or flooding. Understanding hydrodynamic forces is essential for engineers to ensure that coastal structures can withstand the dynamic environment they are placed in.
Integrated drainage systems: Integrated drainage systems are comprehensive frameworks designed to manage stormwater and surface water runoff in a sustainable and efficient manner. These systems combine various techniques, including natural and engineered solutions, to mitigate flooding, improve water quality, and enhance ecosystem functions while also considering the built environment such as bridges and roads.
Kerry S. D. McGowan: Kerry S. D. McGowan is a prominent civil engineer and researcher specializing in coastal infrastructure, particularly focusing on the design and resilience of coastal bridges and roads. McGowan's work emphasizes the importance of integrating advanced engineering techniques with environmental considerations to create structures that withstand the challenges posed by climate change, sea-level rise, and extreme weather events.
Life-cycle cost assessments: Life-cycle cost assessments are a systematic approach to evaluating the total cost of ownership of a project or asset over its entire life span, from initial acquisition through to disposal. This approach not only considers the upfront costs but also includes maintenance, operation, and eventual replacement costs, making it essential for understanding long-term financial implications. By focusing on life-cycle costs, stakeholders can make informed decisions that balance economic efficiency with sustainability, especially in the context of infrastructure such as coastal bridges and roads.
Load Distribution: Load distribution refers to the way in which loads, such as weight or force, are spread out across a structure, ensuring that no single part bears too much stress. Proper load distribution is crucial for the safety and stability of structures like bridges and roads, especially in coastal areas where environmental factors can add additional stresses. Understanding how loads are distributed helps engineers design structures that can withstand both static and dynamic forces, ensuring longevity and resilience.
Modular construction techniques: Modular construction techniques involve the off-site fabrication of building modules or sections, which are then transported and assembled on-site to create a complete structure. This approach allows for faster construction times, improved quality control, and reduced waste, making it particularly beneficial in environments where efficiency and adaptability are critical.
Remote sensing: Remote sensing is the process of acquiring information about an object or area from a distance, typically using satellite or aerial imagery. This technology allows for the collection of data on various environmental and geographical features without direct contact, making it invaluable in monitoring changes in coastal environments and assessing ecological impacts.
Resilient pavement materials: Resilient pavement materials are specially engineered surfaces designed to withstand the stresses and strains associated with vehicular traffic, environmental conditions, and coastal impacts. These materials enhance the durability and lifespan of roadways, particularly in coastal areas where saltwater, flooding, and erosion can compromise structural integrity. Their resilience not only supports infrastructure but also contributes to overall coastal resilience by minimizing maintenance costs and improving safety for travelers.
Robert M. G. Ahlfeld: Robert M. G. Ahlfeld is a notable figure in coastal engineering, recognized for his contributions to understanding and improving coastal resilience, particularly in the context of infrastructure like bridges and roads along coastlines. His work emphasizes the importance of adapting these structures to withstand the challenges posed by climate change, such as rising sea levels and increased storm intensity, thus ensuring their longevity and safety.
Sea Level Rise: Sea level rise refers to the increasing average level of the world's oceans due to factors such as climate change, melting ice caps, and thermal expansion of seawater. This phenomenon significantly impacts coastal areas by altering ecosystems, increasing flooding risks, and influencing coastal infrastructure and communities.
Sediment Transport: Sediment transport refers to the movement of solid particles, such as sand, silt, and clay, from one location to another due to the action of water, wind, or ice. This process is crucial in shaping coastlines and is influenced by various factors including waves, currents, tides, and human interventions.
Storm Intensity: Storm intensity refers to the measure of the strength and severity of a storm, often determined by its wind speed, precipitation rates, and atmospheric pressure. It plays a crucial role in predicting the potential impact of storms on infrastructure and the environment, particularly in coastal areas where bridges and roads are frequently subjected to extreme weather conditions.
Storm surge barriers: Storm surge barriers are large structures designed to protect coastal areas from flooding caused by storm surges during severe weather events like hurricanes. These barriers can be closed during storms to prevent rising water from inundating vulnerable regions, providing crucial defense against high tides and storm-induced waves. Their design and implementation are vital in maintaining infrastructure resilience, especially in urban settings that face increasing climate-related risks.
Structural Health Monitoring Systems: Structural health monitoring systems are integrated technologies used to assess the condition and performance of structures over time, ensuring safety and functionality. These systems utilize various sensors and data collection techniques to monitor factors like stress, strain, and vibrations, providing real-time insights into structural integrity. In the context of coastal bridges and roads, they are crucial for detecting issues caused by environmental conditions and heavy usage, enabling timely maintenance decisions.
Wave deflectors: Wave deflectors are structures designed to redirect wave energy and reduce erosion along coastlines. They play a crucial role in coastal engineering by altering wave patterns, thereby protecting infrastructure such as roads and bridges from potential damage caused by storm surges and high-energy waves. By efficiently managing wave action, they help maintain the stability of coastal areas, ensuring safer access and transportation.
Wildlife underpasses: Wildlife underpasses are specially designed structures that allow animals to safely cross under roads and highways, reducing the risk of vehicle collisions and promoting wildlife connectivity. These structures are crucial in areas where roads fragment habitats, helping to maintain healthy ecosystems by enabling species to move freely between habitats for food, breeding, and migration.
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