Views: 221 Author: Site Editor Publish Time: 2026-02-26 Origin: Site
Content Menu
● The Fundamental Pillars of Bridge Longevity
● Technical Characteristics of Bailey Beams and Modular Trusses
>> Key Features of EVERCROSS Bailey Systems
● Professional Installation Methods: Bailey Beams and Launching Gantries
>> 1. The Launching Nose Assembly
>> 2. Using the Launching Gantry
>> 3. Step-by-Step Installation Sequence
● Comprehensive Maintenance of Steel Truss Bridges
>> Corrosion Protection: The Battle Against Oxidation
>> Inspection Checklist for Longevity
● Advanced Value: Structural Health Monitoring (SHM)
● Why Global Leaders Choose EVERCROSS BRIDGE
● Summary of Maintenance Best Practices
● Frequently Asked and Questions regarding Maintenance of Steel Truss Bridges
>> Q1: How often should a steel truss bridge be inspected?
>> Q2: Why is Hot-Dip Galvanizing preferred over industrial paint for Bailey bridges?
>> Q3: What is the primary cause of structural failure in modular steel bridges?
>> Q4: Can a Bailey bridge be used as a permanent structure?
>> Q5: What role does a launching gantry play in maintenance?
In the global infrastructure landscape, the maintenance of steel truss bridges is not merely a technical requirement; it is a critical strategy for ensuring the safety and economic viability of transport networks. As a premier manufacturer with an annual output exceeding 10,000 tons, EVERCROSS BRIDGE has established itself as a leader in the industry, partnering with global giants like CCCC (China Communications Construction Company), CREC (China Railway Group), and PowerChina. Drawing on decades of expertise in providing structural solutions for railway, highway, and international government projects, we present this comprehensive guide on maximizing the life-cycle of modular steel bridges.
The longevity of a steel truss bridge is determined long before the first vehicle crosses its deck. It begins with high-quality material selection—specifically Q355B high-strength structural steel—and rigorous manufacturing standards. However, even the most robust bridge faces environmental challenges: moisture, salt, thermal expansion, and fatigue.
Strategic maintenance of steel truss bridges involves a multi-layered approach:
●Corrosion Mitigation: Preventing the chemical breakdown of steel.
●Structural Integrity Monitoring: Ensuring connections remain tight and aligned.
●Load Management: Monitoring traffic to prevent fatigue beyond design limits.
To understand maintenance, one must first understand the structure. Bailey bridges, particularly the 321-type and 200-type modular systems manufactured by EVERCROSS BRIDGE, are renowned for their versatility.
●Modular Versatility: Composed of standardized truss panels, transoms, and stringers that allow for rapid assembly and disassembly.
●High-Strength Pins: The "heart" of the truss, where panel pins made of specialized alloy steel transmit the primary shear forces.
●Advanced Surface Treatment Processes: Our company offers a variety of surface treatment processes, including sandblasting, dip coating, spray painting, hot-dip galvanizing (HDG), and zinc-aluminum alloy coating. We also recommend hot-dip galvanizing (HDG) as the primary rust prevention measure, which can provide a maintenance-free service life of 50-100 years.
Feature | 321-Type Bailey Bridge | 200-Type Bailey Bridge |
Panel Size | 3.0m x 1.5m | 3.0m x 2.134m |
Main Material | Q345B / Q355B Steel | Q355B High-Tensile Steel |
Connection | Panel Pins & Chord Bolts | Panel Pins & Enhanced Bracing |
Best For | Temporary construction/Rapid response | Permanent high-load highway bridges |
Proper installation is the "Zero-Step" of maintenance. A bridge installed with internal stresses or poor alignment will fail prematurely. At EVERCROSS BRIDGE, we advocate for the Cantilever Launching Method—the safest and most efficient installation technique for steel truss systems.
Before the main bridge is pushed, a launching nose (a lighter, tapered version of the truss) is assembled. This nose reaches the opposite pier first, counteracting the cantilever's gravity and guiding the main structure into place.
For large-scale highway projects involving precast segments or heavy Bailey Beams, a launching gantry is employed.
●Setup: The gantry's main beam is positioned across two piers.
●Lifting: A winch trolley lifts the pre-assembled Bailey truss segments.
●Positioning: The segments are moved longitudinally along the gantry and lowered into the precise bearing positions.
●Foundation Preparation: Ensure abutments and piers are leveled and rollers are installed.
●Roller Placement: Rocker rollers are placed at the launch side to allow the truss to slide smoothly.
●Assembly: Connect panels using panel pins, ensuring the "safety clips" are correctly engaged.
●Pushing: Use hydraulic jacks or winches to push the assembly forward.
●Jack-Down: Once the nose reaches the target pier, the entire bridge is jacked down onto its permanent bearings.
Routine maintenance of steel truss bridges can be categorized into three levels: Routine Cleaning, Anti-Corrosion Refurbishment, and Component Replacement.
Corrosion is the single greatest threat to bridge longevity. Traditional painting requires repainting every 7–15 years. However, modern standards favor Hot-Dip Galvanizing (HDG).
●The HDG Advantage: By immersing the steel in molten zinc, a metallurgical bond is formed. This provides cathodic protection, meaning the zinc will sacrifice itself to protect the underlying steel even if scratched.
●Maintenance Tip: For painted bridges, areas showing "red rust" must be wire-brushed to bare metal and treated with a zinc-rich primer immediately.
●Pin & Bolt Integrity: Check for "fretting corrosion" (fine brown powder) around panel pins, which indicates movement and wear.
●Deck Drainage: Ensure drain holes are clear. Standing water on a bridge deck is a primary catalyst for corrosion of the stringers and transoms.
●Bearing Lubrication: Bearings must allow for thermal expansion. If a bearing "seizes," the resulting stress can buckle a truss member.
As an industry leader, EVERCROSS BRIDGE recommends integrating structural health monitoring (SHM) into permanent bridge projects. This is a "future-oriented" approach to bridge maintenance.
●Digital Twin Technology: By installing IoT sensors (strain gauges, accelerometers, and thermometers), we create a digital replica of the bridge.
●Real-Time Load Tracking: Identify if the bridge is consistently being overloaded by heavy freight.
●Fatigue Analysis: Predict when a specific member might reach its fatigue limit before visible cracks appear.
●Vibration Monitoring: Detect shifts in the bridge's natural frequency, which often signals hidden structural damage.
Our collaboration with CNOOC, Gezhouba Group, and the Ministry of Transport is built on a foundation of reliability. We don't just sell steel; we provide a life-cycle partnership. Our production capacity ensures that even in emergency repair scenarios—such as flood-damaged crossings—we can deliver thousands of tons of Bailey bridge components within weeks.
Strategic Benefits of EVERCROSS Partnership:
●Compliance: All bridges meet AASHTO and ISO standards.
●Customization: Tailored launching gantry designs for complex terrains (deep valleys or fast-moving water).
●Expertise: On-site technical guidance for international government procurement projects.
Maintenance Action | Frequency | Primary Focus |
Visual Inspection | Quarterly | Debris removal, drainage check, accident damage |
Fastener Check | Annually | Tightening chord bolts and inspecting pin clips |
Corrosion Assessment | Every 2 Years | Monitoring HDG thickness or paint integrity |
Structural SHM Review | Continuous (Auto) | Load-bearing capacity and fatigue stress |
The maintenance of steel truss bridges for longevity is a discipline that combines traditional engineering with modern technology. By selecting high-quality Bailey Beam systems from a manufacturer like EVERCROSS BRIDGE, you ensure a foundation of durability. Through proper installation with launching gantries, proactive corrosion control, and the implementation of Structural Health Monitoring, the service life of these critical assets can be extended far beyond a century, providing safe passage for generations to come.
Routine inspections should occur every 2 years under standard conditions. However, "Red List" bridges or those in coastal/high-salt environments require annual check-ups to identify early-stage corrosion.
HDG provides a thicker, more durable coating that bonds metallurgically to the steel. It offers up to 75–100 years of maintenance-free life, whereas paint typically requires significant touch-ups or complete repainting every 10–15 years.
The most common causes are uncontrolled corrosion and fatigue from overloading. Improperly maintained pins and bolts can also lead to "slop" in the truss, increasing dynamic impacts and accelerating wear.
Yes. While often used for temporary access, modern versions like the 200-type Bailey bridge are designed with high-strength steel and HDG coatings, making them suitable for permanent highway use with a 50+ year design life.
A launching gantry is primarily for installation and major rehabilitation. It allows for the precise placement of heavy truss segments without the need for large ground-based cranes, which is essential in environmentally sensitive or geographically restricted areas.
