Vietnam, a Southeast Asian nation stretching over 3,260 kilometers along the Indochinese Peninsula, is defined by its complex geographical and climatic conditions. With a network of over 2,360 rivers, an 8,623-kilometer coastline, and a landscape dominated by mountainous regions (covering 75% of the country), the nation faces unique infrastructure challenges. Its tropical monsoon climate—characterized by high temperatures (25–35°C year-round), extreme humidity (average 80–85%), annual rainfall of 1,500–3,000 millimeters, and frequent typhoons (5–7 major storms annually)—exerts severe stress on transportation infrastructure. As Vietnam undergoes rapid economic growth (GDP expanding at 6–7% annually pre-pandemic) and urbanization (over 40% of the population now lives in cities), the demand for durable, resilient, and efficient bridges has never been more critical.
Among various bridge types, steel truss bridges stand out as a strategic solution for Vietnam’s needs. Renowned for their structural efficiency, modularity, and adaptability to extreme conditions, steel truss bridges address the nation’s geographical constraints (long spans over rivers and valleys), climatic risks (typhoons, floods, corrosion), and economic priorities (fast construction, low lifecycle costs). Let’s explore the fundamentals of steel truss bridges, analyzes why Vietnam urgently needs this infrastructure solution, outlines the local design standards and manufacturing requirements, and forecasts future trends—providing a comprehensive overview of their role in Vietnam’s infrastructure development.
A steel truss bridge is a load-bearing structure composed of interconnected steel members arranged in triangular frameworks (trusses), which distribute loads efficiently across the entire structure. Unlike solid-beam bridges, trusses leverage the inherent stability of triangular geometry to minimize material usage while maximizing strength—making them ideal for long spans and heavy loads.
Key Components of Steel Truss Bridges
Top and Bottom Chords: Horizontal steel members that resist tensile and compressive forces. Top chords typically bear compression, while bottom chords handle tension.
Web Members: Diagonal and vertical steel rods or beams that connect the top and bottom chords, transferring shear forces and preventing lateral deformation. Common web configurations include Warren (parallel diagonals), Pratt (diagonals in tension), and Howe (diagonals in compression) trusses.
Connections: Bolted, welded, or riveted joints that secure truss members. Modern steel truss bridges prioritize high-strength bolted connections (e.g., A325 or A490 bolts) for durability and ease of maintenance.
Decking: The driving or walking surface, usually composed of concrete slabs, steel grating, or composite materials (steel-concrete) supported by the truss framework.
Piers and Abutments: Concrete or steel supports that transfer the bridge’s load to the ground, with designs tailored to Vietnam’s soil conditions (e.g., deep pile foundations for soft riverbeds).
Common Types of Steel Truss Bridges
Through Truss Bridges: Trusses extend above and below the deck, with the deck passing through the truss framework. Ideal for medium to long spans (50–200 meters) and areas with height restrictions.
Deck Truss Bridges: Trusses lie entirely below the deck, offering unobstructed views and simplified maintenance access. Suitable for urban areas and short to medium spans (30–100 meters).
Cantilever Truss Bridges: Two truss segments extend from piers and meet at the center, enabling spans of 100–300 meters. Well-suited for wide river crossings in Vietnam, such as the Mekong Delta.
Steel truss bridges offer distinct benefits that align with Vietnam’s infrastructure needs:
High Strength-to-Weight Ratio: Steel trusses achieve exceptional strength with minimal material, reducing the overall weight of the bridge. This lowers foundation costs—critical in Vietnam’s soft soil and riverine environments—and enables longer spans with fewer piers, minimizing environmental impact on waterways.
Modular Fabrication and Rapid Construction: Truss components are pre-manufactured in factories, ensuring precision and quality control. These modular parts can be transported via trucks, boats, or even helicopters to remote areas (e.g., Vietnam’s mountainous northwest) and assembled on-site quickly. For a 100-meter span, steel truss bridge construction typically takes 3–6 months, compared to 9–12 months for concrete bridges.
Ductility and Resilience to Extreme Loads: Steel’s ability to deform without fracturing makes truss bridges highly resistant to typhoon-induced wind loads, seismic activity, and flood impacts. During typhoons, the triangular truss structure dissipates wind forces evenly, while bolted connections allow for minor movement without structural failure.
Corrosion Resistance (with Proper Protection): While steel is susceptible to corrosion in Vietnam’s high-humidity and coastal environments, modern protective coatings (e.g., zinc-rich primers, epoxy layers) and cathodic protection systems extend the bridge’s service life to 50–100 years—exceeding the lifespan of concrete bridges in similar conditions.
Sustainability and Recyclability: Steel is 100% recyclable, aligning with Vietnam’s national commitment to green infrastructure (e.g., the National Strategy for Green Growth 2021–2030). Steel truss bridges also require less raw material than concrete bridges, reducing carbon emissions during production.
Easy Maintenance and Retrofitting: Truss members are easily accessible for inspection, repair, and upgrades. Damaged components can be replaced individually, and the structure can be retrofitted to accommodate heavier loads (e.g., increased truck traffic) as Vietnam’s economy grows.
Vietnam’s geographical, climatic, economic, and social conditions create a pressing need for steel truss bridges. Below is a detailed breakdown of the key drivers:
Vietnam’s elongated shape and diverse terrain present significant barriers to transportation connectivity:
River and Coastal Crossings: The Mekong and Red River deltas, home to 60% of Vietnam’s population, require numerous bridges to link cities, towns, and rural areas. Steel truss bridges’ long-span capabilities (up to 300 meters) eliminate the need for multiple piers, reducing disruption to river ecosystems and navigation. For example, the Can Tho Bridge—Vietnam’s longest cable-stayed bridge—incorporates steel truss components to span the Mekong River, connecting Can Tho and Vinh Long provinces.
Mountainous Regions: The northwest and central highlands are characterized by steep slopes and narrow valleys. Steel truss bridges’ lightweight design and modular construction allow for deployment in areas with limited access, as components can be transported via narrow roads or helicopters. In Lao Cai province, steel truss footbridges have been installed to connect remote mountain villages, improving access to education and healthcare.
Coastal Resilience: Vietnam’s extensive coastline is prone to storm surges and erosion. Steel truss bridges’ corrosion-resistant coatings and robust foundations (e.g., pile-supported piers) withstand saltwater exposure and wave impacts better than concrete bridges, which often suffer from spalling and reinforcement corrosion in coastal environments.
Vietnam’s tropical monsoon climate poses severe risks to infrastructure, and steel truss bridges are uniquely equipped to cope:
Typhoon Resistance: With 5–7 typhoons striking annually (e.g., Typhoon Goni in 2020, which caused $4.4 billion in damage), wind load resistance is critical. Steel trusses’ aerodynamic triangular design reduces wind drag and suction, while their ductility prevents catastrophic failure during high winds (up to 250 km/h). The Ho Chi Minh City–Long Thanh–Dau Giay Expressway features steel truss overpasses designed to withstand Category 5 typhoons.
Flood Tolerance: Heavy rainfall during the monsoon season (May–October) causes frequent flooding, submerging bridge piers and decks. Steel truss bridges’ elevated deck designs (above 100-year flood levels) and corrosion-resistant materials prevent water damage, while their modular construction allows for quick repairs if floodwaters recede. In the Red River Delta, steel truss bridges have replaced aging concrete bridges that regularly collapsed during floods.
High Humidity and Temperature Fluctuations: Vietnam’s year-round high humidity (80–85%) and temperature swings (20–35°C) accelerate material degradation. Steel truss bridges’ protective coatings (e.g., ISO 12944 C5-M for coastal areas) and ventilation systems (to reduce condensation in enclosed truss members) mitigate corrosion, ensuring long-term durability.
Vietnam’s rapid economic growth and urbanization demand infrastructure that is efficient, cost-effective, and scalable:
Fast Construction for Expanding Cities: Urban centers like Hanoi and Ho Chi Minh City are experiencing population growth of 3–4% annually, requiring new bridges to alleviate traffic congestion. Steel truss bridges’ modular fabrication reduces on-site construction time by 30–50% compared to concrete bridges, minimizing disruptions to daily life. The Ring Road 3 project in Hanoi uses steel truss overpasses to accelerate construction and improve traffic flow.
Lifecycle Cost Efficiency: While steel truss bridges have higher initial costs than concrete bridges, their longer lifespan (50–100 years vs. 30–50 years for concrete) and lower maintenance costs result in lower total lifecycle costs. A World Bank study found that steel truss bridges in Vietnam have a lifecycle cost 20–30% lower than concrete bridges, thanks to reduced repair and replacement needs.
Support for Trade and Logistics: Vietnam’s status as a manufacturing hub (exporting electronics, textiles, and agricultural products) requires reliable transportation networks. Steel truss bridges’ ability to handle heavy loads (e.g., 40-ton trucks) supports freight movement between ports, factories, and border crossings. The Cai Lanh Port in the Mekong Delta uses steel truss bridges to connect the port to national highways, enhancing logistics efficiency.
Vietnam’s commitment to reducing carbon emissions and protecting the environment makes steel truss bridges an eco-friendly choice:
Reduced Carbon Footprint: Steel production has become increasingly low-carbon, with recycled steel accounting for 60% of global steel output. Steel truss bridges use 30–40% less material than concrete bridges, reducing embodied carbon emissions (CO₂ released during production). A 100-meter steel truss bridge emits approximately 500 tons of CO₂, compared to 800 tons for a concrete bridge of the same span.
Minimal Environmental Disruption: Modular construction reduces on-site construction activity, minimizing soil erosion, noise pollution, and disruption to wildlife. In the Mekong Delta, steel truss bridges have been installed without dredging or disturbing riverbeds, protecting fish habitats and supporting sustainable agriculture.
Alignment with National Green Policies: Vietnam’s National Strategy for Green Growth 2021–2030 prioritizes low-carbon infrastructure. Steel truss bridges’ recyclability and energy efficiency align with this strategy, making them eligible for government incentives and international funding (e.g., from the Asian Development Bank’s Green Infrastructure Fund).
To ensure steel truss bridges meet Vietnam’s safety and durability requirements, they must comply with a combination of local standards (TCVN) and international guidelines. These standards address wind loads, seismic activity, corrosion, and structural safety—tailored to Vietnam’s unique conditions.
The Vietnamese Standardization Society (TCVN) develops and enforces national standards for infrastructure, with key regulations for steel truss bridges including:
TCVN 5534-2019: Design Standards for Highway Bridges: The primary local standard, adapting international best practices to Vietnam’s climate and geography. Key requirements include:
Wind load calculations based on regional typhoon data (maximum wind speeds of 250 km/h for coastal areas, 200 km/h for inland regions).
Seismic design parameters specific to Vietnam’s seismic zones (Zone 1–3, with Zone 3 covering high-risk areas like the central highlands and northwest).
Corrosion protection requirements: Coastal bridges must use ISO 12944 C5-M coating systems, while inland bridges require C4 coatings.
Load combinations: Dead load + live load + wind load + flood load, with a minimum safety factor of 1.5 for truss members.
TCVN 4395-2018: Structural Steel for Bridges: Specifies the quality of steel used in truss bridges, including minimum yield strength (≥345 MPa for web members, ≥460 MPa for chords) and chemical composition (low sulfur and phosphorus content to enhance weldability and corrosion resistance).
TCVN ISO 12944-2018: Corrosion Protection of Steel Structures: Adopted from the international ISO standard, it classifies Vietnam’s environments into corrosion categories (C3 for urban areas, C4 for industrial regions, C5-M for coastal zones) and mandates coating thicknesses (≥400 μm for C5-M environments).
TCVN 10391-2014: Welding of Steel Structures for Bridges: Requires compliance with AWS D1.5 (American Welding Society) standards for truss connections, including non-destructive testing (NDT) of critical welds (ultrasonic testing for internal defects, magnetic particle testing for surface cracks).
Vietnamese bridge designers and manufacturers rely on international standards to supplement local regulations, ensuring compatibility with global best practices:
AASHTO LRFD Bridge Design Specifications: Developed by the American Association of State Highway and Transportation Officials, this standard provides guidelines for load resistance factor design (LRFD), wind load calculations, and fatigue design—critical for steel truss bridges exposed to dynamic loads (e.g., heavy traffic, typhoon winds).
Eurocode 3 (EN 1993): Focuses on the design of steel structures, including truss members, connections, and stability. It is widely used in Vietnam for complex truss configurations (e.g., cantilever trusses) and provides detailed requirements for material properties and weld quality.
Eurocode 8 (EN 1998): Addresses seismic design, offering guidance for designing ductile steel truss bridges that can withstand ground shaking without collapse. This is particularly relevant for Vietnam’s seismic Zone 3, where earthquakes of magnitude 6.0+ are possible.
ISO 6433: Welding of Steel for Bridges: Specifies welding procedures and quality control for steel truss bridges, ensuring consistent weld strength and durability.
API RP 2A: Recommended Practice for Planning, Designing, and Constructing Fixed Offshore Platforms: Used for coastal steel truss bridges, providing guidelines for foundation design in saltwater environments and resistance to wave action.
Steel truss bridge designs in Vietnam must address specific local challenges:
Corrosion Protection: Coastal bridges require a multi-layer coating system (zinc-rich primer + epoxy intermediate + polyurethane topcoat) and cathodic protection (e.g., hot-dip galvanizing for web members) to resist salt spray. Inland bridges use weathering steel (e.g., Corten A) with protective coatings for high-humidity areas.
Wind and Seismic Loads: Truss members are sized to withstand combined wind and seismic loads, with diagonal bracing added to enhance lateral stability. Seismic isolators (e.g., rubber bearings) are installed at pier connections to absorb earthquake energy.
Flood Resilience: Deck elevations are set above the 100-year flood level (as defined by Vietnam’s Ministry of Natural Resources and Environment), and piers are protected with riprap (large rocks) or concrete collars to prevent scour.
Accessibility for Maintenance: Truss bridges include inspection walkways (width ≥1.2 meters) and access hatches for NDT testing, ensuring regular maintenance can be performed efficiently.
Producing steel truss bridges that meet Vietnam’s standards requires strict quality control, advanced manufacturing processes, and compliance with local regulations. Below are the key requirements for factories:
Steel Grades: Factories must use steel that meets TCVN 4395-2018 and international standards (e.g., ASTM A36, A572 Grade 50). High-strength steel (≥460 MPa) is required for truss chords and critical web members, while weathering steel is used for inland bridges.
Material Inspection: Incoming steel is tested for yield strength, tensile strength, and chemical composition using certified laboratories. Defective material (e.g., with cracks or impurities) is rejected to ensure structural integrity.
Corrosion Protection Materials: Coatings must comply with TCVN ISO 12944-2018, with suppliers providing certification for zinc content, epoxy thickness, and UV resistance. Cathodic protection systems (e.g., sacrificial anodes) must meet ISO 14801 standards.
Cutting and Drilling: Truss members are cut using computer numerical control (CNC) plasma or laser cutting machines to ensure precise dimensions (tolerance ±2 mm). Connection holes are drilled using CNC drills to maintain alignment (tolerance ±1 mm), critical for bolted connections.
Welding: Welding is performed by certified welders (AWS D1.5 certified) using shielded metal arc welding (SMAW) or gas metal arc welding (GMAW) for truss joints. Welding procedures are documented in a Welding Procedure Specification (WPS), and all critical welds undergo NDT testing (UT, MT, or radiography) to detect defects.
Assembly: Modular truss sections are assembled in factories using jigs and fixtures to ensure geometric accuracy. Bolted connections are torqued to specified values (per AASHTO standards) using calibrated torque wrenches, and joint tightness is verified with ultrasonic testing.
Coating Application: Surface preparation (shot blasting to Sa 2.5 standard) is performed to remove rust, oil, and debris before coating. Coatings are applied in controlled environments (temperature 15–30°C, humidity <85%) to ensure uniform thickness and adhesion. Coating thickness is measured with magnetic gauges, and adhesion is tested using cross-hatch and pull-off methods.
ISO 9001 Certification: Factories must hold ISO 9001 certification, ensuring a quality management system that covers material inspection, fabrication, welding, coating, and final testing.
Third-Party Inspection: Independent inspectors (e.g., from Bureau Veritas or DNV) verify compliance with TCVN and international standards at each stage of manufacturing, from material receipt to final assembly.
Documentation: Detailed records are maintained for each bridge, including material test reports, welding certifications, coating thickness measurements, and NDT results. This documentation is required for project approval by Vietnam’s Ministry of Transport.
Vietnamese steel truss bridge manufacturers face several challenges, which are being addressed through investment and collaboration:
Skilled Labor Shortage: There is a shortage of certified welders and NDT technicians. Factories are partnering with vocational schools to provide training programs, and international certification bodies (e.g., AWS) are offering courses in Vietnam.
Advanced Equipment Costs: CNC cutting machines, NDT equipment, and coating systems require significant investment. The Vietnamese government provides tax incentives for factories investing in advanced manufacturing technology, and international partnerships (e.g., with Japanese or Korean steel companies) are facilitating technology transfer.
Supply Chain Logistics: Sourcing high-quality steel and coatings locally can be challenging. Many factories import raw materials from China, South Korea, or Japan, while others are investing in local steel production facilities (e.g., Hoa Phat Group’s steel mills) to reduce reliance on imports.
Vietnam’s steel truss bridge development can benefit from global case studies, particularly those from manufacturers like Evercross Bridge that specialize in adapting to tropical and challenging environments:
In 2025, Evercross Bridge won the bid for a 64-meter single-span modular steel truss bridge project in Somalia. The project, designed to connect remote communities across a seasonal river, features the company’s D-type modular truss system— a design highly relevant to Vietnam’s riverine delta regions. Key features include:
Modular Rapid Deployment: The bridge was assembled in 14 days using local labor and minimal equipment, addressing Somalia’s limited construction resources. This speed is critical for Vietnam’s post-disaster reconstruction and rural connectivity projects.
Extreme Weather Resilience: Engineered to withstand cyclonic winds (up to 220 km/h) and high humidity, the bridge uses hot-dip galvanized components and epoxy coatings— a corrosion protection system directly applicable to Vietnam’s coastal and delta environments.
Load Capacity: Designed to support 80-ton trucks, the bridge meets Somalia’s freight transportation needs. For Vietnam, this capacity aligns with the growing demand for heavy-duty bridges connecting ports and industrial zones.
Evercross recently completed five two-lane Bailey truss bridges for PNG’s Telefomin 16 km ring road project, compliant with AS/NZS 5100.6 standards. The project offers valuable lessons for Vietnam’s mountainous regions:
Remote Terrain Adaptability: Components were transported via small aircraft and assembled on-site using hand tools, overcoming PNG’s rugged landscape. This logistics model is ideal for Vietnam’s northwest highlands, where road access is limited.
All-Weather Performance: The bridges are designed to withstand heavy rainfall (3,000+ mm annually) and flooding— conditions nearly identical to Vietnam’s monsoon season. Evercross’s elevated deck design and corrosion-resistant materials prevent water damage, a key requirement for Vietnam’s flood-prone regions.
Community-Centric Design: The bridges provide year-round access to markets, healthcare, and education— a priority for Vietnam’s rural development goals.
The future of steel truss bridges in Vietnam is shaped by economic growth, technological advancement, and environmental priorities. Below are the key trends:
Modular construction will become increasingly prevalent, driven by the need for fast, efficient infrastructure deployment. Factories will produce larger, more integrated truss modules (e.g., 20-meter sections) that can be assembled on-site in days rather than weeks. This trend is supported by Vietnam’s investment in prefabrication yards near major construction sites (e.g., in the Mekong Delta and around Hanoi/Ho Chi Minh City).
Vietnam’s commitment to carbon neutrality by 2050 will drive demand for low-carbon steel truss bridges. Factories will adopt eco-friendly production processes, such as electric arc furnaces (using recycled steel) and water-based coatings, to reduce emissions. The government may introduce incentives for bridges using recycled steel (currently 30% of Vietnam’s steel supply, projected to reach 50% by 2030).
Building Information Modeling (BIM) technology will be widely adopted for steel truss bridge design and construction. BIM allows for 3D modeling, clash detection, and lifecycle management, improving collaboration between designers, manufacturers, and contractors. Vietnam’s Ministry of Transport is promoting BIM use in infrastructure projects, with several pilot projects (e.g., the Long Thanh International Airport access bridge) already using BIM for steel truss design.
As Vietnam expands its transportation network, there will be a growing demand for large-span steel truss bridges (200–300 meters) for cross-river and cross the sea. The planned Mekong Delta Bridge Project, connecting Ca Mau and Kien Giang provinces, will feature steel truss segments with spans of up to 250 meters. Additionally, steel truss bridges will be used in offshore wind farm projects, connecting wind turbines to the mainland.
Vietnam has over 10,000 aging bridges (many built in the 1970s–1990s), most of which are concrete. Steel truss bridges will play a key role in retrofitting these structures, with truss components added to enhance load capacity and resilience. The government’s National Bridge Renovation Program (2021–2030) allocates $2 billion for upgrading aging bridges, with steel truss retrofits identified as a cost-effective solution.
The Vietnamese government will continue to support steel truss bridge development through policy incentives and infrastructure investment. The National Transport Master Plan 2021–2030 allocates $50 billion for road and bridge projects, with a focus on steel structures. Additionally, international funding agencies (e.g., the World Bank, Asian Development Bank) are providing loans for steel truss bridge projects, recognizing their resilience and sustainability.
Steel truss bridges are emerging as a cornerstone of Vietnam’s infrastructure development, offering a perfect balance of strength, durability, and adaptability to the nation’s geographical and climatic challenges. Their modular design, rapid construction, and resistance to typhoons, floods, and corrosion address Vietnam’s most pressing infrastructure needs, while their sustainability aligns with global green growth goals.
To fully realize their potential, Vietnam must continue to strengthen its design standards, invest in advanced manufacturing technology, and develop a skilled workforce. By adhering to local (TCVN) and international (AASHTO, Eurocode) standards, manufacturers can produce steel truss bridges that meet the highest safety and durability requirements. As Vietnam’s economy grows and urbanization accelerates, steel truss bridges will play a critical role in connecting communities, supporting trade, and building a resilient, sustainable transportation network.
The future of steel truss bridges in Vietnam is bright, with trends like modularization, low-carbon production, and digital design driving innovation and efficiency. As the nation faces increasing climate risks and infrastructure demands, steel truss bridges will remain a vital solution—forging durable, resilient connections that support Vietnam’s development for decades to come.
Vietnam, a Southeast Asian nation stretching over 3,260 kilometers along the Indochinese Peninsula, is defined by its complex geographical and climatic conditions. With a network of over 2,360 rivers, an 8,623-kilometer coastline, and a landscape dominated by mountainous regions (covering 75% of the country), the nation faces unique infrastructure challenges. Its tropical monsoon climate—characterized by high temperatures (25–35°C year-round), extreme humidity (average 80–85%), annual rainfall of 1,500–3,000 millimeters, and frequent typhoons (5–7 major storms annually)—exerts severe stress on transportation infrastructure. As Vietnam undergoes rapid economic growth (GDP expanding at 6–7% annually pre-pandemic) and urbanization (over 40% of the population now lives in cities), the demand for durable, resilient, and efficient bridges has never been more critical.
Among various bridge types, steel truss bridges stand out as a strategic solution for Vietnam’s needs. Renowned for their structural efficiency, modularity, and adaptability to extreme conditions, steel truss bridges address the nation’s geographical constraints (long spans over rivers and valleys), climatic risks (typhoons, floods, corrosion), and economic priorities (fast construction, low lifecycle costs). Let’s explore the fundamentals of steel truss bridges, analyzes why Vietnam urgently needs this infrastructure solution, outlines the local design standards and manufacturing requirements, and forecasts future trends—providing a comprehensive overview of their role in Vietnam’s infrastructure development.
A steel truss bridge is a load-bearing structure composed of interconnected steel members arranged in triangular frameworks (trusses), which distribute loads efficiently across the entire structure. Unlike solid-beam bridges, trusses leverage the inherent stability of triangular geometry to minimize material usage while maximizing strength—making them ideal for long spans and heavy loads.
Key Components of Steel Truss Bridges
Top and Bottom Chords: Horizontal steel members that resist tensile and compressive forces. Top chords typically bear compression, while bottom chords handle tension.
Web Members: Diagonal and vertical steel rods or beams that connect the top and bottom chords, transferring shear forces and preventing lateral deformation. Common web configurations include Warren (parallel diagonals), Pratt (diagonals in tension), and Howe (diagonals in compression) trusses.
Connections: Bolted, welded, or riveted joints that secure truss members. Modern steel truss bridges prioritize high-strength bolted connections (e.g., A325 or A490 bolts) for durability and ease of maintenance.
Decking: The driving or walking surface, usually composed of concrete slabs, steel grating, or composite materials (steel-concrete) supported by the truss framework.
Piers and Abutments: Concrete or steel supports that transfer the bridge’s load to the ground, with designs tailored to Vietnam’s soil conditions (e.g., deep pile foundations for soft riverbeds).
Common Types of Steel Truss Bridges
Through Truss Bridges: Trusses extend above and below the deck, with the deck passing through the truss framework. Ideal for medium to long spans (50–200 meters) and areas with height restrictions.
Deck Truss Bridges: Trusses lie entirely below the deck, offering unobstructed views and simplified maintenance access. Suitable for urban areas and short to medium spans (30–100 meters).
Cantilever Truss Bridges: Two truss segments extend from piers and meet at the center, enabling spans of 100–300 meters. Well-suited for wide river crossings in Vietnam, such as the Mekong Delta.
Steel truss bridges offer distinct benefits that align with Vietnam’s infrastructure needs:
High Strength-to-Weight Ratio: Steel trusses achieve exceptional strength with minimal material, reducing the overall weight of the bridge. This lowers foundation costs—critical in Vietnam’s soft soil and riverine environments—and enables longer spans with fewer piers, minimizing environmental impact on waterways.
Modular Fabrication and Rapid Construction: Truss components are pre-manufactured in factories, ensuring precision and quality control. These modular parts can be transported via trucks, boats, or even helicopters to remote areas (e.g., Vietnam’s mountainous northwest) and assembled on-site quickly. For a 100-meter span, steel truss bridge construction typically takes 3–6 months, compared to 9–12 months for concrete bridges.
Ductility and Resilience to Extreme Loads: Steel’s ability to deform without fracturing makes truss bridges highly resistant to typhoon-induced wind loads, seismic activity, and flood impacts. During typhoons, the triangular truss structure dissipates wind forces evenly, while bolted connections allow for minor movement without structural failure.
Corrosion Resistance (with Proper Protection): While steel is susceptible to corrosion in Vietnam’s high-humidity and coastal environments, modern protective coatings (e.g., zinc-rich primers, epoxy layers) and cathodic protection systems extend the bridge’s service life to 50–100 years—exceeding the lifespan of concrete bridges in similar conditions.
Sustainability and Recyclability: Steel is 100% recyclable, aligning with Vietnam’s national commitment to green infrastructure (e.g., the National Strategy for Green Growth 2021–2030). Steel truss bridges also require less raw material than concrete bridges, reducing carbon emissions during production.
Easy Maintenance and Retrofitting: Truss members are easily accessible for inspection, repair, and upgrades. Damaged components can be replaced individually, and the structure can be retrofitted to accommodate heavier loads (e.g., increased truck traffic) as Vietnam’s economy grows.
Vietnam’s geographical, climatic, economic, and social conditions create a pressing need for steel truss bridges. Below is a detailed breakdown of the key drivers:
Vietnam’s elongated shape and diverse terrain present significant barriers to transportation connectivity:
River and Coastal Crossings: The Mekong and Red River deltas, home to 60% of Vietnam’s population, require numerous bridges to link cities, towns, and rural areas. Steel truss bridges’ long-span capabilities (up to 300 meters) eliminate the need for multiple piers, reducing disruption to river ecosystems and navigation. For example, the Can Tho Bridge—Vietnam’s longest cable-stayed bridge—incorporates steel truss components to span the Mekong River, connecting Can Tho and Vinh Long provinces.
Mountainous Regions: The northwest and central highlands are characterized by steep slopes and narrow valleys. Steel truss bridges’ lightweight design and modular construction allow for deployment in areas with limited access, as components can be transported via narrow roads or helicopters. In Lao Cai province, steel truss footbridges have been installed to connect remote mountain villages, improving access to education and healthcare.
Coastal Resilience: Vietnam’s extensive coastline is prone to storm surges and erosion. Steel truss bridges’ corrosion-resistant coatings and robust foundations (e.g., pile-supported piers) withstand saltwater exposure and wave impacts better than concrete bridges, which often suffer from spalling and reinforcement corrosion in coastal environments.
Vietnam’s tropical monsoon climate poses severe risks to infrastructure, and steel truss bridges are uniquely equipped to cope:
Typhoon Resistance: With 5–7 typhoons striking annually (e.g., Typhoon Goni in 2020, which caused $4.4 billion in damage), wind load resistance is critical. Steel trusses’ aerodynamic triangular design reduces wind drag and suction, while their ductility prevents catastrophic failure during high winds (up to 250 km/h). The Ho Chi Minh City–Long Thanh–Dau Giay Expressway features steel truss overpasses designed to withstand Category 5 typhoons.
Flood Tolerance: Heavy rainfall during the monsoon season (May–October) causes frequent flooding, submerging bridge piers and decks. Steel truss bridges’ elevated deck designs (above 100-year flood levels) and corrosion-resistant materials prevent water damage, while their modular construction allows for quick repairs if floodwaters recede. In the Red River Delta, steel truss bridges have replaced aging concrete bridges that regularly collapsed during floods.
High Humidity and Temperature Fluctuations: Vietnam’s year-round high humidity (80–85%) and temperature swings (20–35°C) accelerate material degradation. Steel truss bridges’ protective coatings (e.g., ISO 12944 C5-M for coastal areas) and ventilation systems (to reduce condensation in enclosed truss members) mitigate corrosion, ensuring long-term durability.
Vietnam’s rapid economic growth and urbanization demand infrastructure that is efficient, cost-effective, and scalable:
Fast Construction for Expanding Cities: Urban centers like Hanoi and Ho Chi Minh City are experiencing population growth of 3–4% annually, requiring new bridges to alleviate traffic congestion. Steel truss bridges’ modular fabrication reduces on-site construction time by 30–50% compared to concrete bridges, minimizing disruptions to daily life. The Ring Road 3 project in Hanoi uses steel truss overpasses to accelerate construction and improve traffic flow.
Lifecycle Cost Efficiency: While steel truss bridges have higher initial costs than concrete bridges, their longer lifespan (50–100 years vs. 30–50 years for concrete) and lower maintenance costs result in lower total lifecycle costs. A World Bank study found that steel truss bridges in Vietnam have a lifecycle cost 20–30% lower than concrete bridges, thanks to reduced repair and replacement needs.
Support for Trade and Logistics: Vietnam’s status as a manufacturing hub (exporting electronics, textiles, and agricultural products) requires reliable transportation networks. Steel truss bridges’ ability to handle heavy loads (e.g., 40-ton trucks) supports freight movement between ports, factories, and border crossings. The Cai Lanh Port in the Mekong Delta uses steel truss bridges to connect the port to national highways, enhancing logistics efficiency.
Vietnam’s commitment to reducing carbon emissions and protecting the environment makes steel truss bridges an eco-friendly choice:
Reduced Carbon Footprint: Steel production has become increasingly low-carbon, with recycled steel accounting for 60% of global steel output. Steel truss bridges use 30–40% less material than concrete bridges, reducing embodied carbon emissions (CO₂ released during production). A 100-meter steel truss bridge emits approximately 500 tons of CO₂, compared to 800 tons for a concrete bridge of the same span.
Minimal Environmental Disruption: Modular construction reduces on-site construction activity, minimizing soil erosion, noise pollution, and disruption to wildlife. In the Mekong Delta, steel truss bridges have been installed without dredging or disturbing riverbeds, protecting fish habitats and supporting sustainable agriculture.
Alignment with National Green Policies: Vietnam’s National Strategy for Green Growth 2021–2030 prioritizes low-carbon infrastructure. Steel truss bridges’ recyclability and energy efficiency align with this strategy, making them eligible for government incentives and international funding (e.g., from the Asian Development Bank’s Green Infrastructure Fund).
To ensure steel truss bridges meet Vietnam’s safety and durability requirements, they must comply with a combination of local standards (TCVN) and international guidelines. These standards address wind loads, seismic activity, corrosion, and structural safety—tailored to Vietnam’s unique conditions.
The Vietnamese Standardization Society (TCVN) develops and enforces national standards for infrastructure, with key regulations for steel truss bridges including:
TCVN 5534-2019: Design Standards for Highway Bridges: The primary local standard, adapting international best practices to Vietnam’s climate and geography. Key requirements include:
Wind load calculations based on regional typhoon data (maximum wind speeds of 250 km/h for coastal areas, 200 km/h for inland regions).
Seismic design parameters specific to Vietnam’s seismic zones (Zone 1–3, with Zone 3 covering high-risk areas like the central highlands and northwest).
Corrosion protection requirements: Coastal bridges must use ISO 12944 C5-M coating systems, while inland bridges require C4 coatings.
Load combinations: Dead load + live load + wind load + flood load, with a minimum safety factor of 1.5 for truss members.
TCVN 4395-2018: Structural Steel for Bridges: Specifies the quality of steel used in truss bridges, including minimum yield strength (≥345 MPa for web members, ≥460 MPa for chords) and chemical composition (low sulfur and phosphorus content to enhance weldability and corrosion resistance).
TCVN ISO 12944-2018: Corrosion Protection of Steel Structures: Adopted from the international ISO standard, it classifies Vietnam’s environments into corrosion categories (C3 for urban areas, C4 for industrial regions, C5-M for coastal zones) and mandates coating thicknesses (≥400 μm for C5-M environments).
TCVN 10391-2014: Welding of Steel Structures for Bridges: Requires compliance with AWS D1.5 (American Welding Society) standards for truss connections, including non-destructive testing (NDT) of critical welds (ultrasonic testing for internal defects, magnetic particle testing for surface cracks).
Vietnamese bridge designers and manufacturers rely on international standards to supplement local regulations, ensuring compatibility with global best practices:
AASHTO LRFD Bridge Design Specifications: Developed by the American Association of State Highway and Transportation Officials, this standard provides guidelines for load resistance factor design (LRFD), wind load calculations, and fatigue design—critical for steel truss bridges exposed to dynamic loads (e.g., heavy traffic, typhoon winds).
Eurocode 3 (EN 1993): Focuses on the design of steel structures, including truss members, connections, and stability. It is widely used in Vietnam for complex truss configurations (e.g., cantilever trusses) and provides detailed requirements for material properties and weld quality.
Eurocode 8 (EN 1998): Addresses seismic design, offering guidance for designing ductile steel truss bridges that can withstand ground shaking without collapse. This is particularly relevant for Vietnam’s seismic Zone 3, where earthquakes of magnitude 6.0+ are possible.
ISO 6433: Welding of Steel for Bridges: Specifies welding procedures and quality control for steel truss bridges, ensuring consistent weld strength and durability.
API RP 2A: Recommended Practice for Planning, Designing, and Constructing Fixed Offshore Platforms: Used for coastal steel truss bridges, providing guidelines for foundation design in saltwater environments and resistance to wave action.
Steel truss bridge designs in Vietnam must address specific local challenges:
Corrosion Protection: Coastal bridges require a multi-layer coating system (zinc-rich primer + epoxy intermediate + polyurethane topcoat) and cathodic protection (e.g., hot-dip galvanizing for web members) to resist salt spray. Inland bridges use weathering steel (e.g., Corten A) with protective coatings for high-humidity areas.
Wind and Seismic Loads: Truss members are sized to withstand combined wind and seismic loads, with diagonal bracing added to enhance lateral stability. Seismic isolators (e.g., rubber bearings) are installed at pier connections to absorb earthquake energy.
Flood Resilience: Deck elevations are set above the 100-year flood level (as defined by Vietnam’s Ministry of Natural Resources and Environment), and piers are protected with riprap (large rocks) or concrete collars to prevent scour.
Accessibility for Maintenance: Truss bridges include inspection walkways (width ≥1.2 meters) and access hatches for NDT testing, ensuring regular maintenance can be performed efficiently.
Producing steel truss bridges that meet Vietnam’s standards requires strict quality control, advanced manufacturing processes, and compliance with local regulations. Below are the key requirements for factories:
Steel Grades: Factories must use steel that meets TCVN 4395-2018 and international standards (e.g., ASTM A36, A572 Grade 50). High-strength steel (≥460 MPa) is required for truss chords and critical web members, while weathering steel is used for inland bridges.
Material Inspection: Incoming steel is tested for yield strength, tensile strength, and chemical composition using certified laboratories. Defective material (e.g., with cracks or impurities) is rejected to ensure structural integrity.
Corrosion Protection Materials: Coatings must comply with TCVN ISO 12944-2018, with suppliers providing certification for zinc content, epoxy thickness, and UV resistance. Cathodic protection systems (e.g., sacrificial anodes) must meet ISO 14801 standards.
Cutting and Drilling: Truss members are cut using computer numerical control (CNC) plasma or laser cutting machines to ensure precise dimensions (tolerance ±2 mm). Connection holes are drilled using CNC drills to maintain alignment (tolerance ±1 mm), critical for bolted connections.
Welding: Welding is performed by certified welders (AWS D1.5 certified) using shielded metal arc welding (SMAW) or gas metal arc welding (GMAW) for truss joints. Welding procedures are documented in a Welding Procedure Specification (WPS), and all critical welds undergo NDT testing (UT, MT, or radiography) to detect defects.
Assembly: Modular truss sections are assembled in factories using jigs and fixtures to ensure geometric accuracy. Bolted connections are torqued to specified values (per AASHTO standards) using calibrated torque wrenches, and joint tightness is verified with ultrasonic testing.
Coating Application: Surface preparation (shot blasting to Sa 2.5 standard) is performed to remove rust, oil, and debris before coating. Coatings are applied in controlled environments (temperature 15–30°C, humidity <85%) to ensure uniform thickness and adhesion. Coating thickness is measured with magnetic gauges, and adhesion is tested using cross-hatch and pull-off methods.
ISO 9001 Certification: Factories must hold ISO 9001 certification, ensuring a quality management system that covers material inspection, fabrication, welding, coating, and final testing.
Third-Party Inspection: Independent inspectors (e.g., from Bureau Veritas or DNV) verify compliance with TCVN and international standards at each stage of manufacturing, from material receipt to final assembly.
Documentation: Detailed records are maintained for each bridge, including material test reports, welding certifications, coating thickness measurements, and NDT results. This documentation is required for project approval by Vietnam’s Ministry of Transport.
Vietnamese steel truss bridge manufacturers face several challenges, which are being addressed through investment and collaboration:
Skilled Labor Shortage: There is a shortage of certified welders and NDT technicians. Factories are partnering with vocational schools to provide training programs, and international certification bodies (e.g., AWS) are offering courses in Vietnam.
Advanced Equipment Costs: CNC cutting machines, NDT equipment, and coating systems require significant investment. The Vietnamese government provides tax incentives for factories investing in advanced manufacturing technology, and international partnerships (e.g., with Japanese or Korean steel companies) are facilitating technology transfer.
Supply Chain Logistics: Sourcing high-quality steel and coatings locally can be challenging. Many factories import raw materials from China, South Korea, or Japan, while others are investing in local steel production facilities (e.g., Hoa Phat Group’s steel mills) to reduce reliance on imports.
Vietnam’s steel truss bridge development can benefit from global case studies, particularly those from manufacturers like Evercross Bridge that specialize in adapting to tropical and challenging environments:
In 2025, Evercross Bridge won the bid for a 64-meter single-span modular steel truss bridge project in Somalia. The project, designed to connect remote communities across a seasonal river, features the company’s D-type modular truss system— a design highly relevant to Vietnam’s riverine delta regions. Key features include:
Modular Rapid Deployment: The bridge was assembled in 14 days using local labor and minimal equipment, addressing Somalia’s limited construction resources. This speed is critical for Vietnam’s post-disaster reconstruction and rural connectivity projects.
Extreme Weather Resilience: Engineered to withstand cyclonic winds (up to 220 km/h) and high humidity, the bridge uses hot-dip galvanized components and epoxy coatings— a corrosion protection system directly applicable to Vietnam’s coastal and delta environments.
Load Capacity: Designed to support 80-ton trucks, the bridge meets Somalia’s freight transportation needs. For Vietnam, this capacity aligns with the growing demand for heavy-duty bridges connecting ports and industrial zones.
Evercross recently completed five two-lane Bailey truss bridges for PNG’s Telefomin 16 km ring road project, compliant with AS/NZS 5100.6 standards. The project offers valuable lessons for Vietnam’s mountainous regions:
Remote Terrain Adaptability: Components were transported via small aircraft and assembled on-site using hand tools, overcoming PNG’s rugged landscape. This logistics model is ideal for Vietnam’s northwest highlands, where road access is limited.
All-Weather Performance: The bridges are designed to withstand heavy rainfall (3,000+ mm annually) and flooding— conditions nearly identical to Vietnam’s monsoon season. Evercross’s elevated deck design and corrosion-resistant materials prevent water damage, a key requirement for Vietnam’s flood-prone regions.
Community-Centric Design: The bridges provide year-round access to markets, healthcare, and education— a priority for Vietnam’s rural development goals.
The future of steel truss bridges in Vietnam is shaped by economic growth, technological advancement, and environmental priorities. Below are the key trends:
Modular construction will become increasingly prevalent, driven by the need for fast, efficient infrastructure deployment. Factories will produce larger, more integrated truss modules (e.g., 20-meter sections) that can be assembled on-site in days rather than weeks. This trend is supported by Vietnam’s investment in prefabrication yards near major construction sites (e.g., in the Mekong Delta and around Hanoi/Ho Chi Minh City).
Vietnam’s commitment to carbon neutrality by 2050 will drive demand for low-carbon steel truss bridges. Factories will adopt eco-friendly production processes, such as electric arc furnaces (using recycled steel) and water-based coatings, to reduce emissions. The government may introduce incentives for bridges using recycled steel (currently 30% of Vietnam’s steel supply, projected to reach 50% by 2030).
Building Information Modeling (BIM) technology will be widely adopted for steel truss bridge design and construction. BIM allows for 3D modeling, clash detection, and lifecycle management, improving collaboration between designers, manufacturers, and contractors. Vietnam’s Ministry of Transport is promoting BIM use in infrastructure projects, with several pilot projects (e.g., the Long Thanh International Airport access bridge) already using BIM for steel truss design.
As Vietnam expands its transportation network, there will be a growing demand for large-span steel truss bridges (200–300 meters) for cross-river and cross the sea. The planned Mekong Delta Bridge Project, connecting Ca Mau and Kien Giang provinces, will feature steel truss segments with spans of up to 250 meters. Additionally, steel truss bridges will be used in offshore wind farm projects, connecting wind turbines to the mainland.
Vietnam has over 10,000 aging bridges (many built in the 1970s–1990s), most of which are concrete. Steel truss bridges will play a key role in retrofitting these structures, with truss components added to enhance load capacity and resilience. The government’s National Bridge Renovation Program (2021–2030) allocates $2 billion for upgrading aging bridges, with steel truss retrofits identified as a cost-effective solution.
The Vietnamese government will continue to support steel truss bridge development through policy incentives and infrastructure investment. The National Transport Master Plan 2021–2030 allocates $50 billion for road and bridge projects, with a focus on steel structures. Additionally, international funding agencies (e.g., the World Bank, Asian Development Bank) are providing loans for steel truss bridge projects, recognizing their resilience and sustainability.
Steel truss bridges are emerging as a cornerstone of Vietnam’s infrastructure development, offering a perfect balance of strength, durability, and adaptability to the nation’s geographical and climatic challenges. Their modular design, rapid construction, and resistance to typhoons, floods, and corrosion address Vietnam’s most pressing infrastructure needs, while their sustainability aligns with global green growth goals.
To fully realize their potential, Vietnam must continue to strengthen its design standards, invest in advanced manufacturing technology, and develop a skilled workforce. By adhering to local (TCVN) and international (AASHTO, Eurocode) standards, manufacturers can produce steel truss bridges that meet the highest safety and durability requirements. As Vietnam’s economy grows and urbanization accelerates, steel truss bridges will play a critical role in connecting communities, supporting trade, and building a resilient, sustainable transportation network.
The future of steel truss bridges in Vietnam is bright, with trends like modularization, low-carbon production, and digital design driving innovation and efficiency. As the nation faces increasing climate risks and infrastructure demands, steel truss bridges will remain a vital solution—forging durable, resilient connections that support Vietnam’s development for decades to come.
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