Should the joints of the upright posts in a disc-coupler steel pipe formwork support system be staggered?

On construction sites, disk-coupler steel tube scaffolding is becoming increasingly widespread thanks to government promotion and has become the preferred choice for construction projects.
Due to its high safety, ease of operation, and low material wastage, it can meet a wide range of complex construction needs and is easily applicable to various applications, whether it be double-row exterior scaffolding or formwork support systems.
In recent years, various regions have explicitly restricted the use of traditional coupler-type steel tube scaffolding and have comprehensively promoted the use of socket-type disk-coupler steel tube scaffolding.
Compared to traditional coupler-type steel tube scaffolding, disk-coupler steel tube scaffolding offers numerous irreplaceable advantages.
Disk-coupler steel tube scaffolding is divided into two types based on its construction application:
One is disk-coupler steel tube formwork support scaffolding,
and the other is disk-coupler steel tube exterior scaffolding.

 

 

                                    I. Disk-Coupler Steel Pipe Formwork Support Scaffolding

The Safety Technical Standards for Socket-Type Disk-Coupler Steel Pipe Scaffolding in Construction (JGJ/T 231-2021) does not explicitly require that the joints of upright posts in socket-type disk-coupler steel pipe formwork support scaffolding be staggered. Therefore, the joints of the upright posts in the formwork support scaffolding do not need to be staggered, and arranging the joints at the same height complies with the code requirements. In tall formwork support systems (frame height > 8 meters), it is recommended that upright joints be staggered to enhance stability.

 

 

                                      II. Disk-Coupler Type Steel Pipe External Scaffolding

According to Section 6.3.3 of the Safety Technical Standards for Socket-Type Disk-Coupler Steel Pipe Scaffolding in Construction (JGJ/T 231-2021), the vertical posts on the first level of a double-row external scaffold should preferably be arranged in a staggered pattern using posts of different lengths, and adjustable bases or shims should be installed at the base of the vertical posts.
The reason for staggering the joints of the vertical posts in external scaffolding is that, due to the height of the scaffold structure, the vertical posts on the windward side may be subjected to tensile forces under horizontal wind loads.
According to JGJ/T 231-2021, the joints of vertical posts in disk-coupler steel tube external scaffolding must be staggered. 

 

                                                                                     III. Summary

According to JGJ/T 231-2021, the joint requirements for upright posts in disk-coupler steel tube formwork support systems and disk-coupler steel tube exterior scaffolding are as follows:
1. Joints in the upright posts of disk-coupler steel tube formwork support systems do not need to be staggered. However, in tall formwork systems (where the scaffold height exceeds 8 meters), it is recommended to stagger the upright post joints to enhance stability.
2. Joints in the vertical posts of disk-coupler steel tube exterior scaffolding must be staggered.