Structural connections in circular concrete

Abstract

Several researches have been done in the last decade about the possibility to “give a new life” to the second-hand reinforced concrete elements of a certain building which has been (fully/partly) disassembled. However, not often the actual technical detailing of their reuse practice are addressed. This study is primarily focused on proposing the most suitable solutions to what concerns the reintegration of these structural second-hand parts into a “host” structure, which can contain other reused elements or can be a mixture of new and second-hand parts. The overall approach to the previously mentioned task is structured as follows: -Four structural systems have been considered to formulate the input list of elements for which re-connection approaches need to be formulated; -Connection approaches have been formulated for the elements which have been considered suitable for a potential reuse; -Selected connection methods from the ones formulated above have been studied in detail, assuming to embed them in a hypothetical office building made partially of second-hand elements. From the first part it have been assumed that common columns, shallow beams, load bearing wall panels and one way slabs such as hollow core slabs and plank-floors can be potentially reused. In the second phase several connection approaches have been formulated, highlighting briefly their constructional details and specifying their advantages and drawbacks. Some of these resulted in having different degrees of overall complexity. In any case the proposed designs are requiring more investigation before being actually put in practice, since, for some methods a significantly different design from the one used for traditional connections was used. In the last part, regarding the case study of selected jointing methods, it was chosen to address three approaches: the connection of a second-hand column to the foundation block, a splice joint on a column and a complete study of a columns-to-shallow beams node. In final result it has been deduced that, even if the feasibility regarding the use of second-hand elements requires a careful preliminary assessment and a detailed study about the cost-effectiveness of the details, the proposed connections could be potentially successfully embedded in a new structures. This point has been also confirmed by the positive output results obtained at the end of the analysis of the case-study.