Development of lining formwork for column expansion during reconstruction of building and structures

The paper highlights the relevance of the use of stay-in-place formwork systems in improving the load-bearing capacity of columns by way of their expansion during reconstruction of buildings and structures. The review of a number of scientific publications has revealed that the current phase of development of this topic is seeing increased popularity of lining formworks made of composite materials. Therefore, a new formwork system is proposed, which can be made of various materials, such as: steel fiber reinforced concrete, fiber reinforced foam concrete or the composite material PENACOM. A stay-in-place (lining) formwork consists of regular-course and edge assembly elements (sections) forming two openended three-dimensional U-type shapes (shop-fabricated), which, when coupled, make a square or rectangular configuration of the necessary size. Reliable coupling of the elements is achieved by puzzle connections linked both vertically (to form sections) and horizontally (to form semi-sections). The paper describes the assembling technology for lining formworks and compares it with a conventional small-panel wooden formwork, as well as pneumatic and universal formworks previously developed by the authors with the use of composite materials.