Vertical Formwork Systems: Crane-Dependent Systems
6.1 Introduction to Vertical Formwork Systems
6.2 Conventional Wall/Columns Forming Systems
6.3 Ganged Forming Systems
6.4 Jump Forms
Formwork development has paralleled the growth of concrete construction throughout the twentieth century. As concrete has come of age and been assigned increasingly significant structural tasks, form manufacturers have had to keep pace. Form designers and builders are becoming increasingly aware of the need to keep abreast of technological advancements in other materials fields in order to develop creative innovations that are required to maintain quality and economy in the face of new formwork challenges.
Formwork was once built in place, used once, and subsequently wrecked. The trend today, however, is toward increasing prefabrication, assembly in large units, erection by mechanical means, and continuing reuse of forms. These developments are in keeping with the increasing mechanization of production in other fields.
Vertical formwork systems are those used to form the vertical supporting elements of the structure—columns, core walls, and shear walls. The functions of the vertical supporting systems are to transfer the floor loads to the foundation and to resist the lateral wind and earthquake loads. Consequently, the construction of vertical structural elements precedes flat horizontal work. Typical vertical formwork systems utilized in construction include conventional formwork, ganged forms, jump forms, slipforms, and selfraising forms.
Formwork systems for vertical concrete work can be classified into two main categories, namely, crane-dependent systems and crane-independent systems. Gang formwork and jump form
are classified under crane-dependent systems. On the other hand, slipform and self-raising formwork are classified as crane independent systems in which formwork panels are moved vertically by other vertical transportation mechanisms. This chapter focuses primarily on crane-dependent formwork systems and their application and limitations.
The conventional wall system is the only hand-set system. The other four formwork systems are made of prefabricated modular panels before they can be transported by cranes or any other vertical transportation system.