Conference Publications

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3D physical model study for proposed remedial works to the Port of Richards Bay breakwaters
(2024-04) Wehlitz, Carl-Peter FV; Mabille, Eugene
The Port of Richards Bay is frequently subjected to extreme storm events where recorded wave heights can easily exceed five meters. Over the last two decades, these storms have caused significant damage to the port’s breakwaters. A 3D physical model study was commissioned with the objective to assess and verify the stability of four different strategies to repair and enhance the structural integrity of these structures. Results from this study showed that both breakwaters will ultimately fail if no major improvements to these structures are made. The repair options tested for the main breakwater included a comparison of two different toe designs, as well as comparing the performance of two different armour unit types. The outcome indicated that the repairs to the main breakwater will most likely entail a trenched toe design and an armour layer comprising of very large cubic-type blocks. While the repair options tested for the lee breakwater mostly entailed placing additional or larger armour units of the same type, it did allow the opportunity to optimise both the armour unit size and the coverage for an improved overall outcome.
3D Physical model study for the Haifa breakwater retrofit design
(2024-05) Wehlitz, Carl-Peter FV; Somlota, Lukhanyo L
Since the original designs were performed without current wave forecasting data that accounted for climate change and sea level rise, the Port of Haifa is becoming more frequently subjected to extreme storm events. These storms have caused major damage to the port’s main breakwater, and the rock used in the 1930 vintage portion of the structure has deteriorated. A 3D physical model study was commissioned with the objective to assess and verify the stability of a retrofit design proposed to enhance the structural integrity of the main breakwater. The design included major modifications to the structure, with the most prominent being a new armour layer. This would result in the widening of the breakwater, as well as raising the crest. Results from this study showed that a single-layer Cubipod armour layer would be sufficient to cope with the extreme conditions tested. A variation to the design was, however, required at two sections of the breakwater where World War II vintage historic fire command towers are located. This is because design restrictions prohibited any alterations to these towers and the adjacent crest areas. The variations included a milder seaward slope, as well as constructing a double-layer armour layer at these locations.
A case for high capacity coal trucks to reduce costs and emissions at Eskom
(2021-07) De Saxe, Christopher; Van Eeden, J; Steenkamp, A; Mokone, Olwethu
South Africa’s national power utility, Eskom, is under heavy strain to maintain an undisrupted electricity supply and contain costs, while at the same time reducing its environmental impact. In 2018/19, Eskom acquired 118 Mt of coal, at a purchase cost of approximately R 47 billion, of which around R7 billion (15%) can be attributed to the transport of coal via conveyor, rail and road. Eskom has been unable to meet its road-torail modal shift targets, and so road haulage still accounts for around 30% of coal deliveries. The “Smart Truck” or “PBS” demonstration project in South Africa has shown how an innovative approach to truck design and regulation can drastically improve the efficiency of road haulage, reducing the cost per tonne-km, while reducing emissions and improving safety. An existing Smart Truck trial in coal transport has demonstrated a 15% reduction in fuel use and associated carbon emissions per tonne-km, which translates into an approximate 6% reduction in total road transport costs. This was achieved through the introduction of innovative 74-tonne tridem interlink truck combinations, which has resulted in fewer truck trips and reduced costs for the same haulage task. At the same time, the trucks are more road friendly due to additional axles and fewer truck trips, and the trucks are designed to be inherently safer than the conventional coal interlinks currently in use. In this paper, we benchmark the costs and emissions of Eskom’s current road haulage coal supply operations in South Africa, and calculate the potential savings from migrating to 74tonne interlink PBS truck combinations. We demonstrate potential savings of R 120 million and 35 000 tonnes of CO2 per year, while removing 300 000 truck trips from the roads.
A survey of logistics skills in South Africa: Identifying logisticians of the future
(2025-10) Dondofema, Richmore A
South Africa faces major structural challenges, including an unemployment rate of 27%, which rises to 55% among youth. Although Africa's most advanced economy, it has underperformed compared to other middle-income countries, leading to a critical skills shortage, particularly in logistics. Results of this study show that while there are adequate traditional logistics skills, there is an increasing need for technologically adept logisticians due to rapid advancements, requiring expertise in data analytics, telecommunications, and environmental management. Future logisticians must understand value creation, identify market opportunities, and possess both technical and soft skills to succeed in the evolving logistics landscape.
Accelerated Pavement Testing (APT) of a test section surfaced with an asphalt wearing coarse containing plastic waste incorporated using the ‘wet method’
(2025-07) Smit, Michelle A; Rust, FC; Mturi, Goerges; Mokoena, Refiloe; Ntombela, R; Marais, Herman
The incorporation of plastic waste in road pavement materials presents a promising opportunity for sustainable infrastructure development. In South Africa, introducing any innovation requires compliance with national performance criteria and guidance from mechanistic-empirical design methods. This study evaluated the rutting resistance performance of a road pavement section surfaced with plastic waste modified asphalt (PWMA) produced via the wet method – where plastic waste is integrated into the bituminous binder before mixing. An Accelerated Pavement Testing (APT) program was adopted for the permanent deformation testing of a coarse continuously-graded asphalt wearing course modified with plastic waste. The PWMA was produced with post-consumer recycled plastic waste and also incorporated a Reactive Elastomeric Terpolymer (RET). Test sections were constructed in Gauteng, South Africa, comprising a reference asphalt (based on a standard unmodified bitumen used in South Africa) structure and a PWMA layer. Both sections were subjected to simulated traffic loading using a Heavy Vehicle Simulator (HVS) at speeds of 12km/h, varying wheel loads (40, 60 and 80 kN dual wheel load), and controlled temperatures reflective of local pavement conditions. Performance monitoring involved surface and embedded measurement tools, including Road Surface Deflectometer (RSD), Multi Depth Deflectometer (MDD), standard straight edge, thermocouples and temperature buttons. After 2.9 million equivalent standard axles (ESALs) of HVS loading, the PWMA section demonstrated enhanced rutting resistance, with an average rut depth of 7.2 mm, compared to 10.4 mm for the reference section, which reached a maximum rut of 12mm.These results align with laboratory findings, confirming that the addition of plastic waste increases the structural integrity of asphalt layers by enhancing resistance to permanent deformation. This study supports the potential for adopting PWMA in South African road infrastructure to meet national performance standards and sustainability goals.
An examination into prospective research areas concerning the safety of learner transport, specifically focusing on intentional harm
(2024) Rathogwa, Mashudu
The focus of this presentation was to highlight potential strategies for addressing the current deficiencies in research and practical actions aimed at strengthening school security procedures.
An examination into prospective research areas concerning the safety of learner transport, specifically focusing on intentional harm (Conference Paper)
(2024) Rathogwa, Mashudu
In South Africa, as of 2018, the alarming statistic of one child being abducted every five hours highlights a pressing concern for the safety of school children. What compounds this issue is the stark inadequacy of school security procedures in place to thwart potential abductions. Criminal syndicates, notorious for their meticulous and thorough operations, often exploit schools by infiltrating them under the guise of concerned parents. Kidnappings and abductions cut across socioeconomic boundaries, impacting both the underprivileged and affluent segments of society. The motives of these kidnappers encompass physical violence, financial exploitation, and even the gravest outcome, murder. In response to this disturbing trend, this research aims to highlight the existing gaps in both the research and practical measures that can be taken to fortify school security protocols, ultimately ensuring the safety of learners against kidnappings and abductions.
Analytical techniques to quantify modifiers in bitumen for the South African asphalt pavement industry
(2021-07) Makhari, A; Hawes, Nomashaka BN; Mturi, George AJ; Ojijo, Vincent O
Modifying bitumen is currently a common practice in South Africa. The asphalt pavement industry has seen an increase in use of different types of modifiers in an attempt to improve or extend the properties of bitumen. Common modifiers used in South Africa include plastomers (e.g. ethylene vinyl acetate or EVA), elastomers (e.g. styrene-butadiene-styrene or SBS) and warm mix additives (e.g. waxes). Bitumens are already complex materials which can be represented mechanically and rheologically with mathematical models. Recently, the need to also characterise the in situ structural and chemistry effect of modifiers within bitumen has been appreciated, in order to determine their influence on modified bitumen performance. This paper explores the analysis of bitumen with various modifiers using Fourier Transform Infra-Red (FTIR) spectroscopy and Differential Scanning Calorimetry (DSC). Special attention is paid to quantification of these modifiers in bitumen as a quality control and forensic investigative tool, due to the current asphalt failure challenges facing the industry. The aim is to accurately determine the extent of modification through analytical techniques as a monitoring tool for the better construction of asphalt pavement roads. The paper shows such analytical scientific techniques have the potential to quantify locally used modifiers in South African bitumen.
Application of drones and image processing for bridge inspections in South Africa
(2021-07) Kemp, Lana; Roux, Michael P; Kemp, Mauritz J; Kock, R
In South Africa, visual inspections for all bridge structures are required every five years. A need was identified to establish if it would be practical to utilise technologies, such as drones and photogrammetry, to improve inspections and to reduce the cost of inspections. Drone and photogrammetry technologies are large components in the Fourth Industrial Revolution (4IR). For proof of concept, two bridges were inspected us-ing a drone. The drone inspection data captured for the two bridges was processed and point cloud models were created. These point cloud models were then used to estab-lish whether defects, identified on these bridges previously by way of regular TMH 19 visual assessments, could be identified from the point cloud models. The outcome of the study showed that it would be possible to use processed images from drone in-spections or other image capturing methods to inspect bridges and for monitoring pur-poses. The use of these technologies could improve the inspection methodology, not only of individual structures, but also of a network of structures as required by road au-thorities. Recommendations are made for future work.
Assessing catenary arches for bridge design in South Africa: A preliminary study
(2025) Chirwa, Mary
Bridges form a vital component of South Africa’s transport infrastructure, yet many are susceptible to failure due to environmental stressors and suboptimal design. Recent disasters, including the 2024 KwaZulu-Natal floods, have underscored the fragility of current bridge systems and the need for resilient structural solutions. While circular arches are prevalent due to their historical effectiveness, this preliminary study investigates the viability of catenary arches as an alternative. Through comparative finite element analysis, the structural performance of catenary and circular arches was evaluated, focusing on moment and stress distribution, deformation, and material efficiency. Results reveal that catenary arches offer more balanced internal force distribution, reduced material consumption, and enhanced resistance to lateral forces. These characteristics suggest that catenary forms may serve as a more resilient and cost-effective bridge solution in regions prone to extreme conditions. This study lays the groundwork for further optimisation and supports the integration of catenary geometries into future South African bridge designs.
Best practices in support of vulnerable road user protection in South Africa
(2023-07) Barnard, HC; Venter, Karien
Vulnerable road user fatalities continue to make up the bulk of road traffic related deaths in South Africa. Safe System-based measures aim to improve the safety of the road environment for all road users including vulnerable road users. Safe System-based measures are primary mitigation measures that focus on reducing the severity of accidents while supporting techniques and measures that focus on reducing the number of accidents. Road Restraint Systems (RRS) form a vital part of the road planning and design process in support of minimising the severity of accidents, including accidents involving vulnerable road users. The uptake of best practices relating to the provision of safe and forgiving roads that can mitigate the severity of injuries in South Africa, has been poor. This research paper considers the plight of vulnerable road users in the South African road environment and provides practical evidence/examples of existing scenarios where roadside risk for vulnerable road users such as non-motorised transport users can be addressed through the provision of correct and crash tested RRS that contribute to making the road environment inherently safe and more forgiving.
Bridge CNN defect prediction models using existing image data
(2022-11) Kemp, Lana; Roux, Michael P; Steyn, WJvdM
In South Africa, it is a requirement for all road agencies to conduct principal visual inspections of all bridge structures every five years. Smaller municipalities do not always have the necessary funds available for principal bridge inspections, resulting in either bridge inspections not being executed, or inspections being done by unqualified people. This paper intends to investigate the possibility of using existing bridge inventory and inspection image data to develop Convolutional Neural Network (CNN) models to predict and classify bridge defects autonomously. This research aims to improve the quality of bridge inspections and condition ratings assigned to defects to be more consistent and not reliant on human subjectivity. These models could ultimately be used for quality control in a Bridge Management System (BMS). The CSIR STRUMAN BMS contains inspection and inventory images captured during principal visual bridge inspections. As a proof-of-concept, bridge roadway joints were considered. 600 images of bridge roadway joints captured in the system were classified according to Defect and No Defect datasets. Different CNN classification models were developed to predict whether an image of a bridge roadway joint contained a defect or not. The image datasets were used to train, validate, and test the performance of the CNN models. The performance of the CNN models was evaluated using a Confusion Matrix and Classification report to select the best-performing model. In conclusion, the selected model was evaluated when introduced to new unseen images. The best performing CNN model utilised transfer learning and data augmentation to predict with 95% accuracy from images if a bridge roadway joint had a defect and with 65% accuracy if the bridge roadway joint had no defect.
Classification of trucks using camera data
(2021-07) Mokone, Olwethu; De Saxe, Christopher
Understanding the precise movements of different commodities on South African roads can help in not only describing the logistics sector more accurately, but also in the planning of road infrastructure maintenance and investment. Truck combinations can be classified into several classes broadly associated with different commodity groups, including tautliners, tankers, flatbeds (general freight) and flatbed (containerised freight). Current truck classification systems in South Africa can classify trucks by number of axles and vehicle mass but are unable to determine the combination type and hence commodity group. Video data allows for truck combinations to be classified in more detail using image-based classifiers. The latest developments in deep learning algorithms have made it possible for accurate classification of vehicle types using camera data. A CCTV camera feed of a section of the N3 was provided by the South African National Roads Agency Limited (SANRAL) and was used as a case study to develop a proof-of-concept classifier for tautliner and tanker truck combinations, using a transfer learning approach and the pretrained ResNet50 classifier. The results indicate good accuracy based on relatively small datasets. Future work will focus on further optimisation and investigating the training dataset requirements in more detail.
Climate Change Risk and Vulnerability Assessments and Adaptation strategies for South African Ports
(2024-04) Van Ballegooyen, R; Siyakatshana, Njabulo; Engelbrecht, F; Daniels, T; Beakam, V; Rossouw, M; Mateyisi, Mohau J; Troch, Christophe NA; Zwane, Nosipho; Smith, G; Mbatha, N
South Africa's ports play a major role in the country's economy. Should climate-related infrastructure damage or operational disruption occur, this could have severe "knock-on" effects to the wider economy. Consequently, Transnet, since 2010, has been in the process of developing an integrated Climate Change Strategy across its operations, commencing with a preliminary Risk and Vulnerability assessment for all Transnet Operating divisions in 2010, followed in 2014 by a first-level risk and vulnerability assessment for the Transnet National Port Authority to assess potential drivers of climate-change risk to port infrastructure, operational support systems, activities related to safety and long-term sustainability of the eight ports they presently manage. Only once the climate-related changes in these key environmental drivers are adequately understood and characterised at a local scale, is it possible to assess climate change risks in each port with sufficient rigour to ensure that any proposed adaptation measures are both appropriate and economically justified. Presented here is initial progress with a TNPA-funded, multi-year, collaborative effort by a consortium of scientist and engineers from range of local institutions and consultancies in making such a detailed Climate Change Risk and Vulnerability Assessment informing the development of Adaptation strategies for South African Ports.
Climate resilience in urban transport planning: A case study of Cosmo City’s wetland dilemma
(2025-07) Kgoa, Lerato
Urban transport planning in climate-sensitive regions requires balancing accessibility needs with environmental sustainability, particularly in informal settlements. This paper examines the dilemma surrounding an operational informal taxi rank located in an ecologically sensitive area near wetland in Cosmo City, Johannesburg. Ideally situated for community access, the rank serves as a vital transit hub for workers, scholars, and traders. However, its location raises concerns about climate resilience and ecological impact, as the area is prone to flooding and holds significant biodiversity value. While formalising the rank would enhance safety and infrastructure, relocation to a non-wetland area risks underutilisation, as seen with a nearby formal facility that remains unused due to its inconvenient location. Using available environmental, land use and transport data, this paper explores the trade offs between environmental risks and community benefits in maintaining the taxi rank’s current location. By weighing climate resilience considerations against transport accessibility needs, the study offers insights into adaptive strategies for transport infrastructure in vulnerable urban areas. This case presents a broader challenge for Southern African cities, emphasising the need for context-sensitive solutions that address both climate resilience and societal demands. The paper invites debate on sustainable urban transport planning in high-density, climate-sensitive regions.
Combining bio-based cementation with cement stabilisation for road construction
(2024-07) Smit, Michelle A; Rust, FC
The growing concerns over climate change and the move towards sustainable, costeffective road development have resulted in the development of bio-based construction methods. Microbial induced calcium carbonate precipitation (MICP) binds material through the formation of calcite bridges between soil grains. Current MICP treatment techniques, however, are not compatible with road construction processes. Due to this the Council for Scientific and Industrial Research (CSIR) has started investigating bio-stabiliser treatment techniques for road construction. The objective of this paper is to present Unconfinded compressive strength (UCS) results for a G8 material stabilised using in-situ bacteria present in the soil. After 10 days of cementation solution treatments a UCS dry result of 1.16MPa was achieved. No wet UCS results were, however, produced as all the samples disintegrated. The decision was made to supplement MICP with 0.7% cement. Not only did UCS wet results show a 100% increase compared with MICP only treated samples, but the UCS dry results were comparable to adding 2.5% cement to the G8 material. Partial replacement of cement with MICP during stabilisation could lead to an overall reduction in the amount of cement used in road construction without compromising strength, which will have a positive environmental and economic impact.
Community perspectives as an essential element of resilience thinking: Resilience from a view of inequality
(2020-12) Dlamini, Sifiso B; Meyer, Isabella A
Resilience is a popular concept in development studies, particularly in research and development on how Information and Communication Technologies (ICTs) can be used to improve livelihoods. As much as the primary focus is on using ICTs to deliver services in sectors that operate in resource constrained environments, the question of inequality remains a key consideration. One of the challenges that faces the future of the ICT-related development of communities is the perspectives and perceptions of researchers on communities, particularly in developing countries with remote rural areas. Taking a resilience view on community without addressing the question of inequality leads to biased resilience strategies in the rural communities of developing countries. This paper presents thinking from an ongoing research study that aims to develop a resilience framework and guidelines for the introduction and use of mobile technologies in South African rural schools.
Conceptualising a benefit assessment framework for the South African National Roads Agency Ltd SOC research and development programme
(2021-09) Rust, FC; Sono, P; Van Dijk, G G; Fourie, H; Smit, Michelle A
In low-income countries Research and Development funding is limited and has to be invested with a view of optimum return, both economic return but also “softer” benefits such as human resource development. The assessment of these benefits is therefore important for the long-term sustainability of research and development programmes. Outputs from research and development in roads and transport are often not hard products aimed for the consumer market, but also include new design methods and techniques to enhance the performance of the transport system that cannot be easily quantified with benefit cost analysis alone. The article discusses the development of a framework for the monitoring of the performance of the South African National Roads Agency Research & Development Programme. The framework consists of a Balanced Score Card and a proposed set of indicators that address benefit throughout the innovation value chain.
Creating pathways to impact: Investing in supply chain and logistics capacity development in Africa
(2023-03) Grobbelaar, S; Meyer, Isabella A; Van Eeden, J; Vandaele, N; Van Wassenhove, L; Besiou, M; Decouterre, C; Rafter, S; Nolting, C; Dondofema, Richmore A
African logistics and supply chain management capabilities are essential to the performance of the continent's commercial and humanitarian supply chains. This study reviewed the challenges for researchers and practitioners in advancing logistics and supply chain performance through developing appropriate capabilities. A literature review and landscape mapping were followed by semi-structured interviews with 45 stakeholders from industry bodies, academia, funding bodies, consultants, specialists, and academics, confirming the capability and opportunity gaps in the current landscape. A meta-framework for sustainable institutional capacity development was constructed based on the empirical data that was gathered, and supply chain capacity development recommendations were proposed.
Design approach for the access channel of Port Victoria, Seychelles
(2024-04) Terblanche, L; Rossouw, M; Troch, Christophe NA
Existing spatial and infrastructural limitations of Port Victoria and its potential effect on Seychelles' economy have made the expansion of the port essential for future development. To accommodate postPanamax container vessels and fuel tankers with static drafts of up to 14 m, the port basin and access channel must be expanded and deepened. The design approach for the new access channel comprised: an assessment of the existing vertical and horizontal channel dimensions; a conceptual design, based on empirical channel design guidelines; and a detailed probabilistic assessment using ship motion and navigation simulation models. Fast-time navigation simulations were conducted and supplemented with real-time simulations. The navigation simulation data were statistically analysed to confirm the alignment and horizontal dimensions of the access channel. The vertical dimensions of the channel were determined by a vertical response analysis of the design vessel to ensure sufficient under-keel clearance while transiting the channel. The use of modelling and simulation proved to be valuable in refining the dimensions necessary for the safe navigation and manoeuvring of the proposed design vessels. These dimensions informed the dredging requirements for the project.

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