Document Type : Review Paper


1 Civil Engineering Dept., University of Technology-Iraq, Alsina’a street, 10066 Baghdad, Iraq.

2 Civil Engineering Dept., University of Catholic, Erbil, Iraq.


Formwork systems are required for almost all cast-in-place concrete construction. However, some forms cost too much, often exceeding 30% of the entire cost of the concrete construction. Thus, the stay-in-place (SIP) formwork, a premanufactured permanent constructional member that holds fresh concrete to the intended sizes and stays in the site to afford loads over the construction lifecycle, could be an auspicious alternative to the classic formwork procedure. Several types of stay-in-place (SIP) formworks for columns have been reviewed, like PVC tubes, CFRP, steel tubes, and the composite of two or more types of stay-in-place (SIP) formwork used together. Moreover, some types of concrete and mortar used as stay-in-place (SIP) formwork have been reviewed. The mechanical, restrain, and deformability characteristics of several types of stay-in-place (SIP) formwork system for concrete columns is discussed. Further, the effect of change in the thickness of several kinds of stay-in-place formworks is highlighted. The impact of the change in the strength level of the core of concrete-filled stay-in-place formworks on the confinement efficiency of stay-in-place formwork is also investigated. Finally, the recommendations for futurity researchers in this area are introduced.

Graphical Abstract


  • SIP formwork offers a cost-effective alternative to classic formwork systems, reducing construction expenses
  • The review covers various types of SIP formworks for columns, including PVC, CFRP, steel tubes, and composite material
  • The study explores the mechanical features and confinement efficiency of some SIP formwork types for RC columns
  • The provides valuable insights for future research in this field


Main Subjects

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