Bridges (cable trays) are structures used to support and protect cables, and are widely used in the fields of construction, electric power, and communications. Although it seems to be an industrialised infrastructure, it actually has some interesting cold knowledge and historical stories. Here are some interesting facts about bridge frames:

1. The earliest ‘bridges’ may have been Roman aqueducts 

The elevated aqueducts built by the ancient Romans can be considered one of the earliest ‘bridges’, which were used to support and convey water flow, similar to modern bridges supporting cables.

These stone structures show how early humans used ‘overhead’ means to transmit important resources (water → electricity / data). 2.

2. Bridges were once made of wood 

In the late 1800s and early 1900s, when electric power systems first became widespread, cables were often laid in wooden channels, which were the precursors to modern metal bridges.

Wooden bridges were perishable and flammable and were later replaced by steel and aluminium bridges.

3. Bridges played a key role in the war 

During World War II, military bases, battleships and aircraft factories made extensive use of bridges to lay power and communication lines to ensure wartime power and signal transmission.

Certain military bridges are designed to be quickly disassembled and assembled to adapt to the temporary needs of the battlefield.

4. The colour of the bridge is a mystery 

Different colours of bridges may be used for different purposes (not globally standardised, but customary in some industries): 

Grey: general purpose 

Green: military or specialised environments 

Orange: high-risk areas 

Some data centres use coloured bridges to differentiate between network tiers (e.g. blue = fibre optic, yellow = secure lines).

5. Bridges can be ‘invisible’ 

In modern buildings, bridges are often designed to be hidden and integrated with ceilings and walls (e.g., hollow ceiling bridges in shopping malls and airports).

High-end office buildings even use glass bridge, both aesthetic and can show the sense of technology.

6. The longest bridge systems may be underground 

Bridge systems in large data centres (e.g. Google, Amazon's server farms) can extend for tens of kilometres, longer than many city bridges.

Underground cable bridge networks in mines are similarly impressive in scale.

7. There are ‘smart’ versions of bridges 

The new smart bridges are equipped with sensors that monitor cable temperature, load and even theft (e.g., triggering an alarm if a cable is cut).

Some bridges are designed to be modular, allowing robots to automate wiring or maintenance. 8.

8. Bridges are resistant to earthquakes and typhoons 

In high seismic zones (e.g., Japan, California), bridges use flexible connections or shock absorbing brackets to prevent cables from breaking due to vibrations.

Bridges in coastal areas need to pass salt spray test to avoid corrosion.

9. Artistic value of bridge frames 

In industrial style design, exposed bridge frames become decorative elements (e.g. cafes, LOFT flats).

Artists have made sculptures out of old bridges to symbolise the ‘veins of the city’. 10.

10. ‘Cold’ knowledge about bridges 

✅ Do spiders hate bridges? Some bridges are coated with an insect repellent that reduces the number of spiders that can build webs and clog up the heat.

✅ There are bridges in space! The cable management system on the International Space Station (ISS) is similar in principle to a bridge, but needs to be adapted to a zero-gravity environment.

✅ The most expensive bridge: the bridge used in nuclear power plants need to be resistant to radiation, the cost is more than 10 times the ordinary bridge.

The Future of Bridging 

Wireless Impact: with the development of wireless technologies (e.g. 5G, WiFi 6), the demand for bridging may decrease, but high-voltage power and backbone networks still rely on wired transmission.

Environmentally friendly materials: recyclable aluminium and bio-based plastic bridges are being tested.