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Research Publications (Engineering and Built Environment)

Permanent URI for this collectionhttp://ir-dev.dut.ac.za/handle/10321/215

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Start date: 2023Subject: search.filters.subject.0905 Civil Engineering

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    Interfacial tensile bond strength between precast rib and cast-in-situ concrete for beam and block slab systems
    (University of the Free State, 2024-06) Khuzwayo, Bonga
    The beam and block slab systems, also referred to as rib and block slab, are widely used in South Africa as a preferred suspended flooring system owing to their structural efficacy and economic viability. According to SANS 1879:2021 guidelines for precast concrete suspended slabs, it is recommended to remove temporary propping for beams and block slabs once the cast-in-situ concrete’s compressive strength surpasses 17 MPa. Notwithstanding the limited availability of literature on the matter, certain manufacturers and structural engineers have raised apprehensions regarding the structural soundness of the interfacial tensile bond strength that exists between precast rib and cast-in-situ concrete, particularly when the compressive strength of concrete is 17 MPa, hence the study. In order to measure the structural soundness of interfacial tensile bond strength, pull-out tests were conducted on precast roughened concrete ribs and cast-in-situ concrete. The study determined that, when the surface roughness was 3 mm, the delamination experiments exhibited a tensile stress of 0.15 MPa, which equates to a compressive strength of 17 MPa for cast-in-situ concrete. Furthermore, the study revealed that the tensile strength attains a value of 0.21 MPa upon attainment of a compressive strength of 25 MPa for concrete, given a surface roughness of 3 mm. The study suggests that an independent mechanism should be devised and implemented to guarantee the structural soundness of the interfacial tensile bond strength between precast ribs and cast-in-situ concrete topping, owing to the low bond strengths.
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    Evaluating the current state of pedestrian facilities in peri-urban and urban areas : a case study of Pietermaritzburg City
    (Bentham Science Publishers Ltd., 2024-04-26) Maseko, Wealthy Tsembile; Adedeji, Jacob Adedayo; Bashingi, Ndakhona; Honiball, James
    Background Pedestrian infrastructure is pivotal for advancing the movement of nonmotorized road users and plays a transformative role in transitioning toward sustainable transportation, especially in rural territories influenced by urban dynamics and interconnected by daily commuter flows. Both walking and cycling stand out as paramount sustainable transport means, offering substantial health and environmental benefits, including reduced noise and air pollution. Multiple factors, such as convenience, safety, accessibility, service cost, flexibility, and the quality of pedestrian pathways, shape individuals' propensity to walk. Notably, in peri-urban contexts, the cost of service becomes a significant determinant, as a notable proportion of the population earns minimal wages or faces unemployment. Objective This study sought to examine the current state of pedestrian walkways within Pietermaritzburg and surrounding areas, through which the accessibility, availability, and quality of these facilities were assessed. The study has suggested possible solutions to address the challenges faced by pedestrians. Methods By conducting semi-structured interviews and leveraging ArcGIS mapping utilities, this research has delineated the existing scenario and offered an initial redesign tailored to pedestrian requirements. Results The data have starkly revealed pervasive inadequacies in the existing pedestrian infrastructure. The functionality and safety of current amenities have been manifestly undermined by these shortcomings. The continuing use of these dilapidated facilities may pose alarming threats not only to pedestrians, but also to other road users.