Bridge Tray (Cable Tray) is a metallic or non-metallic structure used to support and protect cables and pipelines, which is widely used in construction, industry and power systems. Its development reflects the evolution of human needs for cable management. The following is the historical traceability and technological evolution of the bridge.

1. Ancient Origins (Pre-Industrial Era) 

(1) Primitive Support Structures (Wood and Stone) 

Roman and Medieval Architecture: In early buildings, wooden beams or stone channels were used to support ropes, water pipes, or early conductors (e.g., bronze chains).

Mines and tunnels: Wooden supports were used to hold early metal pipes or ropes in mining works.

(2) Cable management before the Industrial Revolution 

18th century Europe: with the experimental use of telegraphy and early electricity, iron hooks or ceramic insulators were used to secure bare wires.

2. During the Industrial Revolution (19th century) 

(1) Telegraph and Early Electricity (1830s-1880s) 

Popularity of telegraph wiring: In the mid-19th century, the telegraph network expanded, and engineers used iron trunking or wooden runners to manage the large number of bare copper wires.

Electric wiring in Edison's time (1880s): Early power systems (e.g., Pearl Street Power Station in New York) used open metal troughs to lay insulated cables, which were the prototype of modern bridges.

(2) Standardisation of metal raceways (1890s-1920s) 

Early forms of steel cable trays: factories began to use open trays made of stamped steel sheets to improve cable heat dissipation.

Demand for fire protection drove improvements: galvanised steel (rustproof) and fireproof coatings began to be used due to the high incidence of electrical fires in the early days.

3. Formation of the modern bridge (20th century) 

(1) 1920s-1950s: standardisation and material upgrading 

Ladder Cable Tray: In the 1920s, American engineers developed the ladder construction to optimise cable heat dissipation and load bearing capacity.

Galvanisation: During the Second World War, galvanised steel bridges became standard in military installations (e.g. warships, airfields).

(2) 1960s-1980s: Diversification and industry norms 

Trough Cable Tray (TCT): Fully enclosed design, suitable for dust-proof and interference-proof environments (e.g. computer rooms).

FRP (Fiberglass Reinforced Plastic) Bridge: In the 1960s, corrosion-resistant fibreglass bridges were promoted in the chemical industry.

International standardisation: 

NEC (National Electrical Code) clarifies the classification of bridges (step, pallet, channel).

IEC (International Electrotechnical Commission) formulated global cable tray standards.

(3) 1990s-2000s: Intelligent and Modular 

Data Centre Requirements: With the development of IT industry, Wire Mesh Tray has been widely adopted for its high ventilation and flexibility.

Modular design: Quick-fit bridges (e.g. snap-in connections) improve construction efficiency. 4.

4. Contemporary Bridge Technology (21st Century) 

(1) New Materials and Environmental Trends 

Aluminium alloy bridge: lightweight, corrosion-resistant, suitable for 5G base stations and new energy facilities.

Fire-resistant bridge: adopting flame-retardant coating or ceramic fibre, complying with the fire code for high-rise buildings (e.g. GB 50016).

Recyclable design: EU RoHS directive promotes the production of lead-free and cadmium-free bridges.

(2) Intelligent and Digital Management 

BIM (Building Information Modeling) Integration: Bridge layout can be optimised by 3D modelling to reduce conflicts.

Intelligent monitoring: some bridges integrate sensors to monitor cable temperature and load in real time.

(3) Emerging Application Areas 

New energy infrastructure: salt spray resistant bridges for photovoltaic power stations and offshore wind farms.

Electric vehicle charging network: high-current cables require high heat dissipation bridge design.

5. Future Development Trends 

Lightweight and High Strength Materials: Carbon fibre composites may enter the bridge market.

Automated installation: robotic construction (e.g. automated cable laying + bridge assembly).

Green certification: low carbon production process (e.g. hydrogen steel bridge).