Home / Cases / Delivery and Application of QDM Movable Scaffolding System for Pingtan Strait Super Sea-crossing Project
Delivery and Application of QDM Movable Scaffolding System for Pingtan Strait Super Sea-crossing Project
Nation: Pingtan Strait
As a world-class super sea-crossing infrastructure project, the Pingtan Strait Rail-cum-Road Bridge faces extremely harsh marine construction conditions all year round, including strong typhoons, high salt fog, severe sea winds and large day-night temperature differences, making the high-altitude cast-in-place box girder construction extremely difficult.
As a world-class super sea-crossing infrastructure project, the Pingtan Strait Rail-cum-Road Bridge faces extremely harsh marine construction conditions all year round, including strong typhoons, high salt fog, severe sea winds and large day-night temperature differences, making the high-altitude cast-in-place box girder construction extremely difficult. China Railway Beijing Engineering Bureau undertook the box girder construction section of the bridge approach. Traditional ground formworks and small bridge erecting machines fail to meet the strict requirements of continuous offshore cast-in-place operation, wind resistance and corrosion resistance. After multiple rounds of technical scheme evaluation and offshore wind tunnel simulation calculations, China Railway Beijing Engineering Bureau customized the QDM enveloping movable scaffolding system (MSS) from Henan Dafang Heavy Machinery, specially designed for on-site casting of double-track box girders of sea-crossing bridges.
Project Execution & Solution Overview
Dafang Heavy Machinery’s custom-built QDM Armored Mobile Formwork Bridge Construction Machine is designed specifically for the on-site casting of dual-line box girders for cross-sea bridges. Key project milestones and engineering solutions included:
Targeted Marine Environment Customization
Dafang’s technical team conducted multiple on-site surveys at the Pingtan Strait construction site, collecting core parameters such as sea wind force, seawater salt fog, pier span and navigation clearance. Targeted optimizations on wind-resistant structure, marine anti-corrosion system and hydraulic synchronous travelling mechanism were completed to fully adapt to extreme sea-crossing construction conditions.
As a thousand-ton-class non-standard special bridge construction equipment for marine projects, the MSS adopts segmented modular production and is delivered to the site by sea in batches. Manufactured in strict accordance with marine engineering standards, the whole production cycle lasts 92 days with a 45-day on-site assembly and commissioning period, ensuring structural stability and operational reliability of the super-large equipment.
After completing on-site segmented assembly, hydraulic connection, overall synchronous commissioning and full-load pressure testing, the equipment successfully passed the third-party safety inspection for marine equipment in one pass. All indicators of wind resistance, corrosion resistance, structural load and synchronous operation meet national standards, and the equipment has been officially put into continuous box girder cast-in-place construction.
High-efficiency Continuous Offshore Construction
Adopting exclusive MSS construction technology, no ground scaffolding is required. The equipment supports rapid single-span casting, automatic form stripping and whole-machine span-crossing cyclic operation, greatly improving the construction efficiency of sea-crossing box girders and shortening the overall construction period of the super project.
Core Technical Features & Advantages
Super Wind-resistant Enclosed Box-type Main Girder
The equipment adopts an under-slung fully enveloping structure with multiple groups of thickened Q355N low-temperature and weather-resistant steel welded main longitudinal beams, which greatly enhances overall rigidity. Wind tunnel tests verify stable and safe operation against Level 8 sea winds. Reinforced truss supports and transverse connecting frames eliminate severe shaking during span crossing, adapting to perennial strong winds in the Pingtan Strait and reducing high-altitude offshore construction risks. All load-bearing welds undergo 100% ultrasonic non-destructive testing to withstand dual loads of thousand-ton self-weight and box girder casting pressure.
Marine-grade Triple Anti-corrosion Coating System
Coastal areas feature extremely high air salinity, which causes severe corrosion on ordinary steel structures within months. The whole MSS adopts a marine-grade three-layer anti-corrosion system: zinc-rich epoxy primer, epoxy micaceous iron intermediate paint and weather-resistant polyurethane topcoat with Dafang’s signature red protective finish. All ladders, maintenance platforms, pin shafts and fasteners are hot-dip galvanized, and salt-fog isolation baffles are added for hydraulic pipelines and electrical supports, ensuring no paint peeling or rusting during long-term offshore outdoor operation and extending the equipment’s service life.
Fully Synchronized Hydraulic & Multi-safety Electrical Control System
Equipped with a multi-cylinder synchronous hydraulic propulsion system, the equipment realizes fully synchronous linkage of form lowering, stripping, longitudinal span crossing and transverse opening & closing with accurately adjustable box girder camber. The electrical system is upgraded to IP56 salt-fog and waterproof grade with built-in dehumidifying and heating modules to prevent condensation in humid offshore environments. Complete safety configurations including real-time wind speed monitoring, automatic wind locking mechanism, overload limit, emergency stop and anti-collision limit are equipped. Dual operation modes of cab control and wireless remote control fully comply with sea-crossing engineering safety standards.
Integrated Formwork System for Continuous Double-track Girder Casting
The QDM movable scaffolding system is equipped with an integrated internal and external formwork and support adjustment system, requiring no additional ground scaffolding. The whole construction process of steel bar binding, concrete pouring and prestressed tensioning can be completed directly on offshore piers. After single-span construction, automatic form stripping and integral span crossing realize continuous cyclic operation. It doubles the construction efficiency compared with traditional supports, greatly shortens the construction period, and perfectly adapts to the casting of large-section dual-track rail-cum-road box girders.
On-Site Delivery & After-Sales
Due to its super-large size, the complete QDM MSS is divided into multiple modules including main girder, scaffolding truss, hydraulic power unit and electrical control system and delivered to the Pingtan site by sea. Our senior structural, hydraulic and electrical engineers were stationed on-site long-term to complete segmented offshore assembly, hydraulic pipeline connection, overall synchronous commissioning and full-load pressure testing. Complete documents including material non-destructive testing reports, marine anti-corrosion certificates and third-party load acceptance reports were delivered for safety filing.
Special practical training for marine environment operation and maintenance was provided on-site, covering shutdown specifications in strong winds and anti-rust maintenance guidelines under salt-fog conditions. 7×24-hour full-cycle remote technical support and sufficient original spare parts such as hydraulic cylinders, frequency converters and synchronous control valves ensure uninterrupted construction of the sea-crossing bridge.
Summary
The QDM enveloping movable scaffolding system applied in the Pingtan Strait super project is a special cast-in-place construction equipment developed by Dafang Heavy Machinery for sea-crossing and river-crossing bridge projects with strong wind and high salt fog. Its core advantages of high wind resistance, marine anti-corrosion performance and synchronous hydraulic continuous construction perfectly solve the difficulties of offshore box girder construction.
Dafang Heavy Machinery can customize QDM/MZ series movable scaffolding systems, bridge erecting machines and bridge & road gantry cranes for railway, highway and sea-crossing infrastructure enterprises. We provide one-stop services including offshore/onsite survey, non-standard scheme design, segmented production and sea transportation, on-site installation & commissioning, and complete engineering inspection documents. Customized solutions and quotations are available for all special bridge construction equipment demands.
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