Experimental investigation of the connection behavior of the corner of the roof to the wall of sandwich panel buildings with shotcrete and presenting a new idea

Examining the connection behavior of the ceiling panel to the wall panel is the most important part of understanding the structural behavior of three-dimensional buildings of sandwich panels with sprayed concrete. In this article, a new idea has been presented by the author in order to connect the corner of the ceiling to the wall due to the high degree of uncertainty of the panels. To use the indefinite degree capacity of these panels in transferring efforts caused by gravity loads and earthquakes. The provided connection, like the panels, are manufactured in a modular and artificial way in the factory and installed in the workshop. The connection is made using the bracing system with the specifications of the welded grid rebar of the panels and is indicated by the abbreviation BWC. The behavior of this type of connection and its comparison with the laboratory results of PCI prescriptive connection details and the laboratory results of connection details based on the design considerations of the ACI code are considered. All the samples have been tested in real scale and under reciprocating load. The results show that the rotational ductility coefficient of BWC connection details is equal to 3.4, for ACI details it is equal to 2.8 and for PCI details it is equal to 2.4, which indicates that the BWC connection sample is more malleable than the other two samples. The bearing capacity of the BWC sample is 0.9 ACI connection details and the failure mechanism in both BWC and ACI samples is due to the stiffness of the panel rebars in the alignment of the connection spring and is of soft failure type. While in the PCI connection details, the failure mechanism was caused by the sliding of the connecting rod in the wall panel of the brittle failure type. The process of reducing the hardness of the BWC connection in different loading steps is very gentle compared to the other two connection details. The results show that the use of the prefab default for this type of buildings and the use of PCI details and instructions for this type of buildings by the manufacturers of this product is incorrect and requires a change of approach. The connection details proposed by the author of BWC have shown good strength and ductility characteristics.