Precast–monolithic frame building system based on permanent reinforced concrete shell formwork: Analysis of world practice and experimental substantiation

Abstract

The paper examines the structural solutions of frame buildings erected by precast–monolithic technology in two consecutive stages — a systematic analysis of world practice and the author’s own experimental verification. The objective is to identify the structural limits of the existing precast–monolithic frame systems, to substantiate the research gap they leave uncovered, and to verify experimentally a solution that fills this gap. More than seventeen foreign and CIS systems (KUB-2.5, ARKOS, RECON, UDS, Deltabeam, IMS, Structurapid, Thomas, RPS, BGK, Filigran and others) were compared against five criteria: the column solution, the beam solution, the floor solution, the detailing of the joint zone, and the limitation reported in the sources. The proposed solution was then tested under static loads on three types of two-bay, two-storey frame models designed at 1:4 scale by similarity theory. Four development directions of precast–monolithic technology were distinguished, and it was shown that none of them extends the principle of load-bearing formwork to the column cross-section. The ultimate load of the proposed solution exceeded that of the mon olithic reference by 2.8 % (134.12 kN against 130.50 kN) and the load at limiting deflection by 3.0 %, while the difference between the longitudinal strains of the shell and the core did not exceed 5 % in the elastic stage. The precast–monolithic frame system based on a permanent shell formwork column is therefore equal in strength and stiffness to monolithic technology and eliminates the joint-zone deficiencies identified in the existing systems.