Portal scaffolding is one of the most widely used scaffoldings in construction scaffolding.
As the main frame is of the “door” type, it is called a portal or portal scaffolding, also called a scaffold or gantry.
This scaffold is mainly composed of a main frame, a horizontal frame, a cross bracing, a scaffolding, an adjustable base, and the like.
The gate scaffold was firstly developed by the United States.
It has the characteristics of simple assembly and disassembly, good load-bearing performance, safe and reliable use, etc.
The development speed is very fast.
The door scaffold is a basic structure composed of a door frame, a cross support, a connecting rod, a hanging buckle type scaffold board or a horizontal frame, a lock arm, etc., and then is provided with a horizontal reinforcing rod, scissor support, a sweeping pole, a sealing rod, a bracket, and a base.
A standardized steel pipe scaffold connected with the main structure of the building is adopted.
Portal steel scaffolding can be used not only as an external scaffolding but also as an internal scaffolding or full scaffolding.
1. It is used for supporting the main frame in the form of building, hall, bridge, viaduct, tunnel, etc.
2. As a high-rise building inside and outside the grid scaffolding.
3. Active working platforms for electromechanical installations, hull repairs, and other renovation works.
4. By using a portal scaffold and a simple truss, temporary residences, warehouses or sheds can be constructed.
5. It is used to set up a temporary watch stand and stand.
At present, there are many technical person in charge of the construction site, and there is no detailed disclosure of the safety technology to the operators.
In addition to the poor quality of some workers, application problems are unavoidable.
If the collapse of the formwork is caused by the operator not setting the spacing of the shear bracing or horizontal and horizontal tie rods according to the design requirements, the stability of the formwork is insufficient; some accidents are caused by the worker dismantling the connecting rod between the external scaffold and the building.
As a result, the overall collapse of the scaffolding has resulted in accidents where piles of building materials, prefabricated structures, or construction equipment have been piled up on scaffolds and formworks, causing partial bar overload instability and causing overall collapse.
Therefore, the management of the construction site is confusing and the operators did not install and dismantle the support in strict accordance with the design requirements, which is also an important reason for the collapse accident.