Masters Degrees (Civil Engineering)

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    The implementation of constructability concepts for design‐bid‐build construction projects
    (Stellenbosch : Stellenbosch University, 2023-11) Simon, Mia; Wium, Jan Andries; Stellenbosch University. Faculty of Engineering. Dept. of Civil Engineering.
    ENGLISH ABSTRACT: The construction industry continually seeks innovative approaches to improve project outcomes and maximize operational efficiency. This study addresses the need for improved constructability considerations during the design phase of design-bid-build projects by introducing an intuitive constructability tool and by advocating intentional collaboration. Traditional procurement methods, such as design-bid-build, retain prominence in the construction industry, particularly for public projects. However, such methods often lack early collaboration between designers and contractors, resulting in missed opportunities for constructability improvements. Concentrating on design-bid-build projects, this study proposes a mobile application as a constructability aid for design engineers to augment their construction considerations during the design phase. It also identified a need to bridge the gap between design engineers and construction specialists through constructability-focused collaboration during mobilization. Despite the significance of constructability considerations in improving construction project outcomes, limited research is available on its implementation in design-bid-build projects. The prevailing literature predominantly focuses on design-build processes, leaving a gap in addressing the unique challenges of early collaboration and knowledge exchange in design-bid-build projects. In this study, construction expert knowledge, obtained through interviews, is utilized in the mobile application and it shows how construction knowledge can be shared with design engineers to support them in creating constructible designs. Additionally, a constructability-centred collaboration plan is presented that project managers can utilize in design-bid-build projects to improve the identification of constructability problems. From the interviewee feedback, 201 advice phrases are derived, which are categorized into 12 groups, shedding light on important aspects of successful project delivery. Distinct clusters of advice were linked to different roles within the construction industry, with practicality, collaboration, and safety as dominant themes. New constructability concepts emerged from these advice phrases, emphasizing mentorship, communication, continuous learning and practical design decisions, unveiling previously unaddressed dimensions. A novel approach, inspired by Integrated Project Delivery (IPD) principles, is presented and validated through interviews with industry participants. Notably, the mobilization phase encompasses activities extending beyond mere site preparation, including project setup, safety planning, project scheduling, contract coordination and stakeholder engagement, which are collaborative activities. Despite the mobilization phase's potential for collaboration, interview feedback reveals a general lack of effective implementation. Challenges identified through the validation interviews relate to biases, resistance to change and difficulties in incorporating diverse perspectives. Six considerations to elevate collaboration, including incorporating positive incentives, tool implementation and fostering a culture of collaboration are presented. The validation interviews confirm the feasibility of this approach, emphasizing the significance of addressing challenges and clarifying participants' responsibilities to drive constructability-centred collaboration. The proposed constructability tool, supported by constructability-focused collaboration during mobilization, holds promise for amplifying project outcomes and instilling a culture of design mindful of construction constraints.
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    The formulation of severity - duration - frequency relationships of drought events in South Africa
    (Stellenbosch : Stellenbosch University, 2023-12) Smith, Esteé; Du Plessis, JA; Stellenbosch University. Faculty of Engineering. Dept. of Civil Engineering.
    ENGLISH ABSTRACT: Drought severity-duration-frequency (SDF) relationships describe the cumulative deficit in precipitation or water availability over time, and are used to assess and visualise the severity and duration of drought events. SDF relationships of droughts are derived by accumulating and standardising the deficit in precipitation or water availability over a specific period, typically based on historical data, to provide a normalised measure of drought severity and duration. Drought indices can be employed to develop SDF curves by providing essential data on precipitation deficits or water scarcity, which are then standardised and cumulatively plotted to visualise the temporal patterns and severity of drought events. Numerous drought indices exist, and each is designed to capture specific aspects of drought conditions, making it essential to select the most appropriate index for a particular region or application. Drought indices rely on a variety of input data, including precipitation, temperature, soil moisture, and streamflow measurements, to assess and characterise drought conditions. Despite its significance and potential utility, South Africa currently lacks comprehensive countrywide SDF curves for drought assessment. The available data input sources in South Africa were assessed, and daily rainfall data from the South African Weather Service (SAWS) and Department of Water and Sanitation (DWS) were selected for analysis. The input data was assessed for minimum record length, record end date, percentage of missing data, homogeneity, and stationarity, and the basic statistics were calculated for each rainfall station. Rainfall stations with data that did not extend beyond the end of 2021, had a record length of less than 30 years, had more than 10% missing data, or displayed inhomogeneity or inadequate stationarity were excluded from analysis. Multiple drought indices were evaluated, and three were chosen for further analysis: the Percentage of Normal Precipitation (PNP), Deciles Drought Index (DDI), and Standardised Precipitation Index (SPI). Various timescales (3-, 6-, 12-, 24-, and 48-months) were computed for the three drought indices to evaluate data availability, particularly in scenarios where decision makers need to make informed decisions but the available data history is relatively short. For the SPI, three distributions (Weibull, Gamma and Log-normal) were examined and tested for goodness-of-fit, and the best-fit distribution was selected for each rainfall station. The development of SDF relationships is based on the use of the SPI. Data was extracted as Partial Duration Series (PDS) to ensure the independence of drought events. The SDF relationships are graphically presented as curves and spatial maps, facilitating a comprehensive assessment of drought severity, duration, and frequency. The results suggest that the DDI and PNP provide similar outcomes in terms of identifying the occurrence of drought events and assessing their duration over shorter timescales, making them viable options in South Africa, particularly when the precise severity of drought is not a primary concern. The SPI identified fewer droughts, but with an increased average drought duration compared to the DDI and PNP. The SDF curves generated from SPI offer valuable insights for when a detailed assessment of drought severity is of primary concern.
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    Physical model tests on stability and overtopping of new concrete armour unit Cubilok™
    (Stellenbosch : Stellenbosch University, 2023-11) Cairns, Melissa; Theron, Dr Andre; Holtzhausen, Anton; Wehlitz, Carl; Stellenbosch University. Faculty of Engineering. Dept. of Civil Engineering.
    ENGLISH ABSTRACT: Artificial concrete armour units are employed to protect coastal structures and infrastructure such as rubble mound breakwaters, revetments, and artificial headlands. Several concrete armour unit types have been developed over the last few decades, where each specific unit has a unique shape and behavioural properties. As the need for breakwaters deployed in harsher wave climates and deeper waters increased, the need for larger armour units also grew. Where concrete armour units are required, generally, the best value is achieved with a single-layer option, provided that construction conditions allow for accurate placement of armour units. PRDW Consulting Port and Coastal Engineers are developing a new concrete armour unit called the Cubilok™. This unit is defined by four principal dimensions, which can be modified to obtain variations of the Cubilok™ shape. These parameters can also be used to alter the structural robustness of the unit, which is indicated by its slenderness ratio (H’). Two different unit shapes have been tested previously: single-layer (H’ = 1.09) and double-layer (H’ = 0.92). For this study, the shape previously tested as a single layer was modified by removing the tapered ends of the protuberance (or arms). These changes were made to reduce the settlement observed in previous research; however, it also resulted in a unit with higher structural robustness where H’ equalled 0.6. This unit’s viability as a single and double layer was investigated in this study. The overall efficacy of an armour unit during wave attack is determined by the hydraulic stability. This study was the first attempt to understand the modified unit’s hydraulic stability and recommended wave overtopping discharge. The primary objective of this research was to investigate the behaviour of the Cubilok at slopes of 1:1.5 and 1:1.33 (V:H), which involved testing various wave heights and periods. A 2D flume configuration was tested at the Council for Scientific and Industrial Research (CSIR) in Stellenbosch, South Africa. The configuration included, a sloping foreshore of 1:30, and a constant water level measured at the structure’s toe. The wave conditions were measured with capacitance probes, and the overlay photography technique was utilised to capture and examine the armour layer reaction. Overtopping volumes were measured throughout testing and converted to l/s/m to indicate the average rate of overtopping discharge. The test schedule included two test series to determine a suitable storm duration for the steeper slope of 1:1.33 (H:V). Packing densities of ∅ = 0.63 and 0.65 were investigated for the storm duration tests. A repeatability test was also conducted for both slopes with the same wave condition. The findings showed an improvement in stability for the tighter packing density; therefore, the test programme continued with the packing density of ∅ = 0.65. According to the stability test results, the armour layer was influenced slightly more negatively by longer wave periods, with larger movements and earlier displacements. By the end of the study, 17 test series were completed, totalling 102 individual tests. The stability number was found to increase with decreasing Iribarren parameters at the start of damage. The inconsistent results achieved at the start of damage yielded no conclusive influence of the varying slope gradients on the hydraulic stability. The average stability numbers achieved for the milder slope were often greater at failure. Throughout testing, the stability numbers ranged from NS = 2.04 to 4.64. At the start of damage, the average stability number was NS = 3.51, and at failure, it was NS = 4.30. The research revealed that the Cubilok's performance notably improved on steeper slopes, indicating competitive potential against other single-layer units. Based on previous research, the Cubilok outperformed Accropode in terms of no damage and design stability at a 1:1.33 slope. However, on steeper slopes, Xbloc's design parameter exceeded Cubilok's by 7%. The overtopping rate increased significantly for low wave steepness values (sop =0.01). For low wave steepness values, the results indicated that the overtopping rate increases approximately twofold with an increase in wave height. Furthermore, compared to the CLASH results of other single-layer units, the measured rate of overtopping for the Cubilok slope was slightly greater. The increased overtopping rate was most apparent in test results with low wave steepness of sop = 0.01, falling outside the CLASH range of sop = 0.02, 0.035 and 0.05. It should be highlighted that this study was only a preliminary investigation into the behaviour of the modified Cubilok. The effect of the packing density and shape were compared in relation to the settlement of the unit. Further tests are recommended to address variability in test results.
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    3D concrete printing technology: enhancing productivity in the South African construction industry – exploring the benefits, barriers, and improvement strategies
    (Stellenbosch : Stellenbosch University, 2023-11) Mogale, Setekoane Phillemon ; Van Zijl, Gideon P.A.G. ; Van Rooyen, Algurnon Steve Tata ; Stellenbosch University. Faculty of Engineering. Dept. of Civil Engineering.
    ENGLISH ABSTRACT: Provided its multitude of benefits, 3D Concrete Printing (3DCP) technology has the potential to transform the South African construction industry, with specific reference to the building sector, by revolutionizing the current traditional construction techniques. However, to fully realize the full potential of this innovative technology, it is of utmost importance to have a comprehensive awareness of its benefits, an understanding of the potential barriers associated with its adoption, and strategic measures tailored to smoothly integrate it into the construction industry. Therefore, this research study aims to comprehensively explore the benefits, barriers, and strategic measures associated with the adoption and implementation of 3DCP technology within the South African construction industry. The research process began by conducting a comprehensive literature study, which delved deep into assessing the current state of 3DCP technology and its application in the construction industry. To fully comprehend the complex dynamics of this technology, a strong foundation was established through the literature study by synthesizing and consolidating information and conceptual frameworks. This assessment process provided insights into the unique potential opportunities and challenges that could be faced by the South African construction industry as it navigates its way into adopting and implementing 3DCP technology as one of the mainstream construction techniques. In addition to this, a survey questionnaire was distributed to various professionals working in the South African construction industry to collect detailed primary data. The survey questionnaire was well designed to probe their perceptions regarding this technology within the South African construction industry given its unique context. The collected data was subjected to a thorough and systematic analysis by applying both descriptive and inferential statistical techniques to determine how the industry perceives the benefits, barriers, and improvement strategies associated with the adoption of 3DCP technology. This systematic analysis yielded a wealth of information that highlighted common trends and main themes that shape the landscape of 3DCP technology adoption within the South African construction industry. The findings of this research highlighted that the South African construction industry is fraught with substantial barriers despite being ripe and well-positioned to embrace the transformative potential of 3DCP technology. The high initial investment was consistently highlighted as the most prevalent barrier, followed by the absence of 3DCP technology experts and the lack of government incentives and support. However, the strategic measures formulated to mitigate these barriers were highly appraised by the professionals, further highlighting the readiness of the industry to leverage this innovative construction technology. Ultimately, these research findings have implications that go beyond mere academic research as they are of significant value for stakeholders with a vested interest in the adoption and successful implementation of 3DCP technology in the South African construction industry. The research study promotes the application of sustainable and efficient innovative construction techniques, tailored to enhance productivity, and encourage environmentally friendly practices, thereby guiding the industry towards a future driven by innovation, competitiveness, and steady growth.
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    Using concepts of building information models to assist emerging contractors
    (Stellenbosch : Stellenbosch University, 2023-12) Saayman, Rolf Bernard; Wium, Jan; Stellenbosch University. Faculty of Engineering. Dept. of Civil Engineering.
    ENGLISH ABSTRACTS: Emerging contractors play a significant role in South Africa’s construction industry. It has been observed that emerging contractors often fail to meet time, cost, and quality targets on projects and therefore fail to become established enterprises. The aim of this study is to investigate a software-based solution to address some of the challenges experienced by emerging contractors. The study investigates the incorporation of concepts of building information modelling (BIM) to improve the efficiency of emerging contractors. A literature investigation was conducted to establish shortcomings of emerging contractors which may prevent them from completing projects successfully. It was found that emerging contractors face numerous complex and multi-facetted problems. However, it was largely determined that emerging contractors amongst others lack projects management skills, financial management skills, and technical expertise. A software application was developed as a proof of concept to support emerging contractors with their project execution. The software application was developed in the Unity game engine as this was established as the best development option for this specific study. A 3D Autodesk Revit model was extracted from the BIM model as an OBJ file and imported into the Unity interface. The software focussed on providing a graphic and visual representation of the project, and of the progress and schedule management to address the lack of project management skills. Furthermore, 3D models providing examples of construction details were developed. To validate the proof of concept the software was presented to six emerging contractors and three industry professionals active in the South African construction industry. The software was well received by all interviewees who also provided feedback and proposed improvements of the current software. Thus, the application of BIM concepts could be of value to emerging contractors. The software also opens the possibility of empowering small contractors on a global scale which could lead to an improved construction industry worldwide. Small contractors play an important role in the industry and are currently not supported by advanced software such as BIM. The use of existing technologies and integration of existing software opens possibilities to the South African construction industry. It is proposed that an open-source software application be developed using the concepts investigated in this study. This will allow participants from industry the ability to add functionality and customise the software for their own needs which will continuously improve the software.