Browsing by Author "Ter Haar, Bjorn"

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    Off-site 3D concrete printing construction system for structural building frames
    (Stellenbosch : Stellenbosch University, 2024-03) Ter Haar, Bjorn; Van Zijl, Gideon P. A. G.; Kruger, Jacques; Stellenbosch University. Faculty of Engineering. Dept. of Civil Engineering.
    ENGLISH ABSTRACT: The human population and urbanisation continue to rise. To provide the economic and social benefits that cities promise, the supply of affordable and adequate housing must match the growing urban population, especially in developing countries. Developing countries, such as South Africa, need to provide adequate housing for millions of people residing in informal settlements. The problem requires a multi-faceted solution. One part of the solution is to improve the productivity of the construction industry through industrialisation. 3D concrete printing (3DCP) and off-site construction (OSC) is a construction technology and approach that promises increased industrialisation and productivity. Structural frames are effective solutions for multi-storey residential buildings. Although 3DCP has successfully been used in several construction projects, few of these projects are multi-storey buildings and none of the buildings utilises a 3D printed concrete (3DPC) structural frame. The lack of research on the use of 3DCP to construct structural frames and the need for the development of 3DCP design and fabrication techniques for multi-storey buildings is identified. Furthermore, the potential to increase the productivity of a construction system by employing OSC techniques is acknowledged. Therefore, this study aims to develop and experimentally evaluate the feasibility of an off-site 3DCP construction system for structural frames of low-rise residential buildings . This dissertation starts by laying a foundation for the development of the construction system using a systematic literature review of both OSC and 3DCP. Thirty-four stakeholder-linked targeted actions which aim to enable the success of off-site 3DCP construction systems are determined. A target frame for the construction system is defined by considering the problem statement and motivation of the dissertation and by conducting case studies of local affordable housing projects. An ideal concept of the off-site 3DCP construction system is defined and a development strategy is formulated using systems engineering tools. Two of the tasks from the development strategy are completed. A novel 3DPC beam is designed, fabricated, and experimentally tested. The beam design methods accurately predicted the flexural resistance of the beam within 6%, however. The study identified that alternative shear design equations are required to predict the shear capacity of 3DPC beams without shear reinforcement. A novel 3DPC https://scholar.sun.ac.za iii pinned demountable beam-column connection is developed, fabricated, and experimentally tested. The connection successfully surpasses the required rotation without undergoing damage, validating its classification as a pinned connection. In essence, this dissertation determines: what is necessary to develop an off-site 3DCP construction system; what the user should be able to build with the construction system, what the construction system should consist of and how can it be developed; how to design and fabricate an off-site 3DPC beam; and how to design and fabricate a demountable pinned 3DPC beam-column connection. The tasks of the defined development strategy that are successfully completed show that 3DPC elements and connections have significant potential to be suitable for structural frames. The off-site 3DCP construction system is shown to be feasible for further development towards the realisation of a full-scale 3DPC structural frame.