Cross-laminated timber (CLT) has experienced growing global popularity in recent years, extending to South Africa with the adoption of SANS 8892 (2020), which allows for local manufacturing of performance-rated CLT. However, this standard requires all locally produced CLT layups to undergo extensive mechanical verification to determine strength and stiffness properties. Analytical methods have proven relatively accurate in predicting the out-of-plane mechanical properties of CLT. Incorporating these methods into design equations can aid in the structural design and sizing of CLT elements. The currently proposed prEN 1995-1-1 (2023) contains design factors specific to CLT, largely common with sawn timber. Adopting such an approach would simplify CLT design in South Africa, using established partial factors, as is the case for plywood. Resistance equations are therefore proposed using existing partial factors for sawn timber design in SANS 10163-1 (2003), incorporating Timoshenko beam theory calculations for bending and shear stresses in CLT. However, the material resistance factor value of 0.68 proposed for sawn timber may be overly conservative due to CLT's inherent load-sharing behaviour. Using the methods outlined by Pagel (2019) and variability results of South African pine-only CLT obtained by Jacobs (2023), an average resistance factor of 0.79 was determined.

The minibus taxi (MBT) is the most widely used mode of public transport in South Africa, accounting for over 66% of peak hour public transport trips. Unlike buses, which benefit from dedicated infrastructure such as bus rapid transit (BRT) lanes with priority transit signals at intersections, MBTs currently lack such priority infrastructure to enhance their efficiency. Efforts by South African road authorities to provide priority infrastructure for MBTs are hindered by the absence of technical guidance on planning, design, and feasibility. This study addresses this gap by developing an analytical method to determine feasible traffic volumes for shared queue bypass priority lanes at pre-timed signalised intersections. The basic problem is that any priority given to MBT vehicles likely reduces the capacity available to other vehicles, which could lead to performance losses. Taking account of this interaction between MBT and general traffic volumes and the reallocation of vehicles to different lanes, we define feasibility as the combination of volumes where capacity is not exceeded for either vehicle type while still offering potential delay savings for MBTs. We produce a set of graphs that can serve as an initial assessment of whether intersections with medium to high MBT volumes may qualify for priority treatment, considering only existing geometric and traffic characteristics. Additionally, the study provides guidance on expected storage lengths for these priority lanes. Overall, the findings indicate that shared queue bypass lanes are effective when medium taxi volumes (approximately 20 PCU/hr to 85 PCU/hr) are present, provided that turning traffic in the shared left-turn lane is not excessively high (between 50 PCU/hr and 640 PCU/hr, depending on green time). Noting that drivers may adapt to priority intersections in unknown ways, we recommend further studies on the traffic safety implications of priority treatments under real operating conditions.

Spillways are designed to control the release of excess water from a reservoir and safely convey it downstream to prevent overtopping and structural failure. The field of stepped spillways hydraulics has seen extensive research, yet several fundamental hydraulic aspects remain inadequately explored. Notably, the elusive safe unit discharge limits for these spillways remain a subject of contention within the existing literature. This paper discusses an investigation into the feasibility of novel deflector forms aimed at increasing the safe discharge capacity of uncontrolled spillways by deflecting the flow away from the spillway slope. A 1:50 scale physical model was constructed to investigate the influence of different deflector forms. The investigation spans a range of prototype unit discharges ranging from 50 m3/s/m to 200 m3/s/m and evaluates factors such as water surface profiles created by the deflector and pressure distribution on the deflector. The proposed novel deflectors developed in this study proved to be effective at various flow rates when the flow trajectory and threshold pressures were considered. These deflectors could be used for dams higher than 150 m and unit discharges between 100 m3/s/m and 200 m3/s/m.

In this study, the thermal response of two reinforced concrete T-beams with identical outer dimensions but differing internal geometry, and therefore different thermal inertia, is investigated. Both T-beams were instrumented with thermocouples and vibrating wire strain gauges and subjected to purely thermal environmental loading. The weighted average (effective cross-sectional) temperature, along with the vertical and transverse temperature distributions, were analysed. In addition, theoretical thermal strains and self-equilibrating stresses were calculated. Uniquely, the mathematical model and assumptions were compared to and validated by experimentally measured strains as opposed to validation through comparisons of predicted temperatures. Effective temperature ranges were related to cross-sectional area per unit width and compared to results from literature. Furthermore, the greatest difference in thermal response between the two sections was found to be effective temperature and subsequent longitudinal movement. Calculated bending moments, caused by thermal loading effects and self-equilibrating stresses, approached 30% of the concrete's ultimate tensile capacity, emphasising their structural relevance.

Gap acceptance and follow-up times are critical parameters in determining the capacity of roundabouts. A major national research project was undertaken by the South African National Roads Agency Ltd (SANRAL) into the design, capacity and operations of roundabouts. This paper provides an overview of the findings and presents the models that were developed to inform the capacity analysis of roundabouts in South Africa. Three important aspects of capacity are addressed, namely i) critical gap acceptance, ii) saturation follow-up headways, and ii) capacity, models. The research was based on data collected using drone video recordings at a total of about 90 roundabouts across the country.

Stagnant productivity and inefficiencies in construction projects often result in cost and time overruns. Lean construction (LC) offers a promising solution by reducing waste and enhancing efficiency. However, its adoption remains limited due to uncertainty and the lack of clarity regarding the use of innovative tools. Existing conceptual frameworks for LC are underutilised due to the absence of a clear implementation roadmap. This study addresses this gap by developing a strategic lean implementation toolbox for organisations new to lean principles, aiming to facilitate early success and long-term integration. A survey of 84 lean practitioners helped identify nine key threats to implementation, which were grouped into four categories: limited knowledge, incorrect selection, improper implementation of tools, and cultural or attitudinal barriers. Strategies to mitigate these threats were drawn from the literature, resulting in the identification of 64 effective practices. These practices were then used to develop a strategic tool, incorporating three complementary toolboxes designed to guide users in selecting lean tools, applying them effectively, and managing organisational and cultural transformation. This study contributes a practical, structured approach for adopting LC, offering the construction industry a strategic roadmap to overcome initial adoption hurdles and manage/sustain innovation more effectively.

Seismic surface wave tests are widely used in geotechnical engineering due to their noninvasive and cost-effective approach in obtaining important soil parameters such as the small strain shear modulus (G 0 ) by measuring shear wave velocity (Vs).While conventional tests focus on measuring Rayleigh waves due to their easy generation and detection in the field, Love waves are often overlooked due to challenges in generating and detecting them.This study investigated the utilisation of both Rayleigh and Love waves to obtain shear wave velocity profiles using experimental and synthetic data.Two methods were explored for generating Love waves -using a horizontal harmonic source, and also employing a horizontal impact source.Signal processing code was developed to analyse the surface wave signals and to calculate dispersion data.By conducting discrete and joint inversions with the experimental and synthetic dispersion data, the variation in the shear wave velocity profiles was evaluated.The findings demonstrated that employing both Rayleigh and Love waves in joint inversion reduced the variation in the shear wave velocity profile compared to using Rayleigh waves alone, but only when Love wave signals with low noise levels were available.

The use of machine learning (ML) to solve civil engineering problems has increased remarkably during the last few decades due to its effectiveness in reliably approximating complex relationships. In this paper, a key parameter of seismic design is estimated using hyperparameter ML algorithms to develop predictive models that compute the fundamental period. Initially, the impact of the train-test split ratio was investigated using three different splits, where the best results were achieved with train-test split ratios equal to 90/10 for all metrics. By predicting the fundamental period with three ML methods, namely XGBoost-HYT-CV, DANN-MPIH-HYT, and RF-HYT, the best fit was acquired by XGBoost-HYT-CV (coefficient of determination R2 = 99.994% and mean absolute error MAE = 0.00428). Although international literature agrees that building height is the primary factor influencing the fundamental period, feature engineering has revealed that the natural logarithm of the percentage of openings is the most significant parameter. This finding underscores the value of feature engineering in generating additional variables and uncovering their impact on output variables. Finally, an equation was derived from POLYREG-HYT that outperformed all existing formulae, deriving a final MAE of 0.0153, approximately three times smaller than the best-performing equations proposed in the international literature.

In the 21st century emphasis has been placed on carbon footprint reduction and a net-zero future. As a water-scarce country, South Africa will face significant water deficits in almost all areas of water management by 2025 (Gebrehiwot & Gebrewahid 2016). Efforts are being made by water service authorities to increase potable water production to cope with increasing population and climate change. In the Umgeni-uThukela water supply system, Mgeni accounts for approximately 80% of the total water supply volume. One of the major concerns in water production is the energy usage and its resulting carbon emissions. The Mgeni system uses approximately 195 795 MWh of energy to produce the water demand for the system. Carbon accounting plays a critical role in ensuring that South Africa meets its international climate change commitments. This study utilised the National Generation Grid Emission Factor (NGGEF), as stipulated in South Africa's 2021 Grid Emission Factors Report (DFFE 2024) The objectives of this study was therefore to: (a) determine the water balance for the Mgeni system, (b) assess the energy usage projection and determine the carbon emissions generated using a carbon balance approach, and (c) determine the future carbon reduction of water losses. The water supply system was analysed using the IWA Standard Water Balance Method, and water losses were determined from the water balance. Further carbon calculations were conducted using the IWA Standard Carbon Balance (Leakage Emissions Initiative). The analysis indicated that the water supplied to the system (SIV) increases from 396 million m3/annum to 510 million m3/annum, while the water losses equate to approximately 133 million m3/annum to 250 million m3/annum. The carbon emissions from majority coal energy generation were approximately 438 526 tCO2/year in 2018, and were shown in this study to increase to 2 703 060 tCO2/year in 2050. With the reduction of water losses, this could decrease by about 18-25%. The carbon emissions produced by renewable energy generation were approximately 333 781 tCO2/year in 2018, with an expected increase to 1 191 831 tCO2/year in 2050. A global study on water distribution systems determined that implementing pressure management could reduce water losses by 38% which ultimately reduces energy consumption by 20-40% (Danfoss 2018). Furthermore, implementation of active leak detection could reduce water losses from leakages by 50%, which would result in reduction in energy consumption and carbon emissions (Ong et al 2023). The water industry must play its part and reduce its greenhouse gas footprint. To achieve net-zero carbon emissions from water production activities, water conservation and demand management strategies, such as pressure management and active leak detection, must be introduced to reduce water losses, thereby reducing energy usage and carbon emissions.

This study examines the fire behaviour of composite slabs made with lightweight concrete, following the fire insulation criteria "I" outlined in Eurocode 4 (CEN 2005). The parametric analysis includes the effect of the airgap, moisture content, thermal properties of the lightweight concrete, and geometrical aspects. Fire resistance time is calculated using two methods - the analytical method from Appendix D of Eurocode 4 (CEN 2005) and a numerical method (ANSYS n.d.). Finite element analysis shows that the moisture content of lightweight concrete significantly impacts fire resistance time. When the moisture content exceeds 3%, the Eurocode method predicts a lower fire resistance time compared to the simulation method. The prediction models indicate that, to achieve the same fire resistance time, a normal-weight concrete section must be 7% thicker than a lightweight concrete section.