In building construction,formwork is used to shape concrete structures(such as floor slabs,beams,columns),while steel props are responsible for supporting the weight of the formwork,concrete,and construction personnel,forming a complete load-bearing system.The connection between steel props and formwork must be firm,reliable,and able to transmit loads evenly,avoiding local stress concentration,formwork displacement,or even collapse caused by loose connections.Different formwork types(such as plywood formwork,steel formwork,aluminum formwork)and construction scenarios(such as floor slab formwork,beam formwork,column formwork)require different connection methods,which need to be selected according to the actual engineering needs and relevant construction standards.
The most common and basic connection method between steel props and formwork is the top plate connection method,which is widely used in ordinary floor slab formwork and light-load beam formwork support.This method uses the top plate(also known as the bearing plate)that comes with the steel prop to connect with the formwork,and the core is to ensure that the top plate is closely attached to the formwork and the load is evenly transmitted.The top plate of the steel prop is usually a circular or square steel plate with a thickness of not less than 5mm(complying with JGJ130-2011 standard),and the surface is smooth to avoid damaging the formwork.
In the top plate connection method,the operation steps are simple:first,adjust the steel prop to the designed height and lock the locking mechanism firmly;then,place the top plate on the top of the steel prop,ensuring that the top plate is horizontally placed and centered with the steel prop(the deviation should not exceed 5mm)to avoid eccentric stress.Next,place the formwork on the top plate,and ensure that the contact surface between the formwork and the top plate is tight without gaps.For plywood formwork,a layer of waterproof film or padding can be laid between the top plate and the formwork to prevent concrete slurry from leaking and protect the formwork.This method is suitable for small-span,light-load scenarios,with the advantages of simple operation,quick installation,and low cost.However,it should be noted that the top plate must be intact without deformation or damage,and the connection between the top plate and the steel prop must be firm to avoid detachment during use.
The U-head connection method is a commonly used connection method for beam formwork,column formwork and large-span floor slab formwork,which has stronger stability and load-bearing capacity than the top plate connection method.The U-head(also known as the U-shaped bracket)is a special adapter installed on the top of the steel prop,which is composed of a U-shaped steel groove and a connecting plate,and can be firmly connected with the formwork keel(such as steel joists,wooden joists).The U-head is usually made of Q235 or Q355 steel,with a thickness of not less than 6mm,and the inner width of the U-shaped groove is matched with the size of the formwork keel to ensure a tight fit.
The operation points of the U-head connection method are as follows:first,install the U-head on the top of the steel prop and fix it with bolts or pins to ensure that it does not loosen;then,place the formwork keel in the U-shaped groove of the U-head,and use bolts or clamping devices to fix the keel in the groove to prevent horizontal displacement.The formwork is then fixed on the keel,forming a stable connection between the steel prop,U-head,keel and formwork.This method can effectively transmit the load from the formwork to the steel prop through the keel,avoiding local stress concentration,and is suitable for medium and heavy-load scenarios such as beam formwork and large-span floor slab formwork.The advantages of this method are strong stability,good load-bearing performance,and easy disassembly and reuse.The key precaution is that the U-head must be matched with the size of the keel,and the fixing bolts or pins must be tightened to ensure that the connection is firm.
The adjustable jacking connection method is suitable for scenarios where the height of the formwork needs to be finely adjusted,such as uneven formwork surfaces or precise elevation control requirements.The adjustable jacking is installed on the top of the steel prop,which can be adjusted up and down within a small range(usually 50-100mm)to ensure that the formwork is at the designed elevation.The adjustable jacking is usually composed of a screw rod,a nut and a top plate,and the adjustment is realized by rotating the nut,with an adjustment accuracy of 1-3mm.
When using the adjustable jacking connection method,first adjust the steel prop to the approximate designed height,then install the adjustable jacking on the top of the prop and fix it;then,rotate the nut of the jacking to adjust the height of the top plate,making the top plate closely attach to the formwork,and lock the nut after adjusting to the designed elevation.This method can effectively compensate for the height error of the steel prop and the formwork,ensuring that the formwork elevation meets the design requirements,and is widely used in high-precision formwork support scenarios such as large-scale commercial buildings and bridge engineering.It should be noted that after adjustment,the nut must be locked firmly to avoid loosening due to vibration during construction,and the adjustable jacking must be inspected regularly to ensure that it is in good condition.
The special adapter connection method is mainly used for special formwork types,such as aluminum formwork,steel formwork,and large-scale prefabricated formwork,which require special adapters to match the connection interface of the formwork.Different formwork types have different adapter structures:for aluminum formwork,the adapter is usually a special connecting plate with holes that match the aluminum formwork bolts;for steel formwork,the adapter is a flange connection structure that can be connected with the steel formwork flange;for prefabricated formwork,the adapter is a customized connector designed according to the formwork interface size.
The special adapter connection method has high compatibility and connection strength,which can ensure that the steel prop is firmly connected with the special formwork,and is suitable for large-scale,high-precision construction projects.The operation steps include:first,install the special adapter on the top of the steel prop according to the formwork type;then,align the adapter with the formwork connection interface,and fix it with bolts,pins or welding(welding is only suitable for permanent connections);finally,check the connection firmness to ensure that there is no looseness or displacement.The advantages of this method are strong adaptability,firm connection,and good load-bearing performance.The key precautions are that the adapter must be customized according to the formwork type and size,and the connection must comply with the formwork manufacturer's specifications and relevant construction standards.
In addition to the above common connection methods,there are also auxiliary connection measures to enhance the stability of the connection between steel props and formwork.For example,in large-span formwork support systems,horizontal bracings and diagonal bracings can be installed between steel props to form an integral support system,reducing the horizontal displacement of the props and the formwork;for high-height formwork support,anti-side displacement devices can be installed between the steel props and the formwork to prevent the formwork from tilting.At the same time,the connection between steel props and formwork must comply with relevant national and industry standards,such as JGJ130-2011《Technical Specification for Steel Pipe Scaffold and Formwork Support in Construction》and GB 50205-2020《Code for Construction Quality Acceptance of Steel Structures》,which clearly specify the connection requirements and quality standards.
It should be emphasized that the connection between steel props and formwork must be inspected strictly before concrete pouring.The inspection contents include:the firmness of the connection,the alignment of the steel prop and the formwork,the tightness of the contact surface,and the reliability of the locking mechanism.For loose connections,they should be tightened in time;for misaligned connections,they should be adjusted;for damaged connectors,they should be replaced immediately.During the concrete pouring process,the connection part should be monitored in real time,and if any abnormal situation(such as loosening,displacement)is found,the construction should be stopped immediately,and the problem should be solved before continuing.
In practical application,the selection of the connection method between steel props and formwork should comprehensively consider the formwork type,construction scenario,load requirements and elevation control requirements.For example,ordinary plywood floor slab formwork can adopt the top plate connection method;beam formwork and large-span floor slab formwork can adopt the U-head connection method;high-precision formwork support can adopt the adjustable jacking connection method;special formwork(such as aluminum formwork)should adopt the special adapter connection method.By selecting the appropriate connection method and strictly following the operation specifications,the stability and reliability of the formwork support system can be ensured,and the construction quality and safety can be guaranteed.
References
1.GB/T 7714 Format
China Construction Third Engineering Bureau Co.,Ltd.Connection Technology Guidelines for Steel Props and Formwork[EB/OL].[2026-04-17].
2.MLA Format
American Concrete Institute."Connection Methods Between Steel Supports and Formwork in Concrete Construction."American Concrete Institute,2026.Accessed 17 Apr.2026.
3.APA Format
Xinfa Yijian Engineering Co.,Ltd.(2026).Connection Quality Control and Operation Norms for Steel Props and Formwork.
4.MLA Format
Brilliance Solution."How to Connect Steel Props with Different Types of Formwork?"Brilliance Solution,2025.Accessed 17 Apr.2026.