Jumpform

Generally, jumpform systems comprise the formwork and working platforms for cleaning/fixing of the formwork, steel fixing and concreting. The formwork supports itself on the concrete cast earlier so does not rely on support or access from other parts of the building or permanent works.

Jumpform, here taken to include systems often described as climbing form, is suitable for construction of multi-storey, vertical concrete elements in high-rise structures, such as:

• Shear walls
• 核心墙
• Lift shafts
• Stair shafts
• Bridge pylons

These are constructed in a staged process. It is a highly-productive system designed to increase speed and efficiency while minimising labour and crane time. Systems are normally modular and can be joined to form long lengths to suit varying construction geometries. Three types of jump forms are in general use:

• 正常的跳跃/攀爬形式：单独从结构上抬起，并使用起重机在下一个施工水平上重新定位。起重机的可用性至关重要。
• Guided-climbing jumpform: also uses a crane but offers greater safety and control during lifting as units remain anchored/guided by the structure.
• Self-climbing jumpform: does not require a crane as it climbs on rails up the building by means of hydraulic jacks.

Benefits

• Fast construction can be achieved by careful planning of the construction process.
• Self-climbing formwork cuts down the requirement for crane time considerably. By allowing the crane to be used for other construction work this may reduce the total number of cranes needed on site.
• The formwork is independently supported, so the shear walls and core walls can be completed ahead of the rest of the main building structure.
• High quality surface finishes can be achieved.
• Climbing forms can be designed to operate in high winds.
• Highly engineered nature of jump form systems allows quick and precise adjustment of the formwork in all planes.
• Some formwork systems can be used at an inclined angle.
• A small but skilled workforce is required on site.
• It is easier to plan construction activities due to the repetitive nature of the work.

Safety

• 工作平台，护栏和梯子都内置在市场领先的模板系统的完整单元中。
• Self-climbing formwork systems are provided with integral free-fall breaking devices.
• 完整的模板组件很健壮。
• 脚手架和临时工作平台的使用减少导致现场交通拥堵减少。
• The setting rate of concrete in those parts of the structure supporting the form is critical in determining the rate at which construction can safely proceed.
• The repetitive nature of the works means site operatives are quickly familiar with health and safety aspects of their job.

Other considerations

• Jumpform通常用于五层或更多层的建筑物；完全自我攀爬的系统通常用于具有20多个楼层的结构。
• Trailing and suspended platforms are used for concrete finishing and retrieving cast-in anchor components from previous pours.

More information on formwork can be sourced fromFormwork for Modern Efficient Concrete Construction，由Bre出版。