Formwork for Concrete Structures by R.L.Peurifoy and G.D- By EasyEngineering.net

280 Chapter Nine
Downloaded From : www.EasyEngineering.net
This enables the gang to resist uplift wind forces and remain fully
engaged in its mounted position.
A typical JumpForm cycle begins by removing all form ties and
anchor positioning bolts. Next, the gang is stripped by turning adjusting
screws on the pipe braces. With the inserts now accessible from the
upper level platform, the landing brackets are attached for the next lift.
At the same time, the wind anchors and finish concrete patching is
performed while working from the lower platform. The crane is then
hooked up to the gang and workers leave the JumpForm. Next, the
JumpForm is lifted and flown to the next level where it automatically
attaches to the landing brackets. Workers then return to the JumpForm
and immediately release the crane. Wind anchors are attached at either
the tie location or the landing bracket inserts. Then, after cleaning and
oiling the gang from the upper platform of the opposite gang, the gang
is plumbed using adjustable pipe braces. Crews can now set all steel
and boxouts, working from the upper level of the opposing form. The
JumpForm cycle is completed by setting the ties and embedments.
ww.EasyEngineering.n
Self-Lifting Wall-Forming System
A craneless forming system for constructing core walls on high-rise
buildings of any size or complexity is available from Patent Construction
System under the trade name, Self-Climber. This wall-forming
system consists of a single, highly mechanized system to support the
gang forms for the entire core. By activating hydraulic jacks from a
central control panel, the Self-Climber raises one floor at a time. In a
short interval, often less than 30 minutes, all forms reach the next
level and preparations begin for the next pour. This is an advantage
over conventional gang forming, where crane-handling increases the
crew size and adds a day or more to the cycling operations. Generally,
a system like this is cost effective only for buildings 15 to 20 stories
or taller.
The superstructure of the wall-forming system consists of lateral
and transverse beams that support all of the Self-Climber’s forms and
platforms. The hydraulic jacks push the superstructure to the next
level, raising all forming and platform areas. Full-height gang forms
feature large plywood sheets for a smooth finish. For architectural
finish, form liners or rustication strips can be used.
A level of scaffold platforms hangs just below the forms to create
comfortable, efficient working spaces; while the platform atop the
superstructure provides a convenient work and storage area. All platforms
travel with the forms. Nothing is dismantled between raises,
an important safety consideration.
All of the jacks are readily accessible, mounted behind the forms.
Each jack is self-contained and has its own pump and reservoir
system to allow for individual control during a raise. There is not a
Downloaded From : www.EasyEngineering.net