Catwalk is a linear temporary construction access road erected under and parallel to the main cable during the construction of suspension bridge. It is a high-altitude scaffold for construction workers and a construction platform for the main cable system and even the whole superstructure of suspension bridge.

the construction personnel complete important tasks such as cable traction, strand adjustment, shaping into saddle, cable tightening, cable clamp and sling installation, box girder hoisting and site connection, main cable winding, protective painting and so on. There is one upstream and one downstream, and the cross section is usually U-shaped, long and narrow with some shaking, so it is called "Cat Lane", and the English name is catway. It is an extremely important temporary facility in the construction of suspension bridge, which will be demolished after the completion of the bridge.

the design of catwalk should follow the principles of simple structure, convenient construction, safety, reliability, economy and rationality. The line shape of catwalk surface should be parallel to the no-load line shape of main cable and keep a certain distance; Try to reduce self-weight and wind area; It is safe and reliable to operate, and can meet the requirements of working face and clearance, strength and stiffness required by mechanical operations such as cable traction and main cable tightening; At the same time, it is required that the installation and disassembly are convenient and quick, and the materials are economical and conducive to fire prevention. In addition, the catwalk cannot have additional influence on the tower, anchorage and main cable.