http://irepo.futminna.edu.ng:8080/jspui/handle/123456789/58 Civil Engineering Tue, 05 May 2026 03:39:33 GMT 2026-05-05T03:39:33Z http://irepo.futminna.edu.ng:8080/jspui/handle/123456789/30832 Title: Physical modelling of offshore wind turbine foundations for TRL (technology readiness level) studies Authors: Bhattacharya, S; Lombardi, D; Amani, S; Aleem, M; Prakhya, G; Adhikari, S; Abdullahi, A Abstract: Offshore wind turbines are a complex, dynamically sensitive structure due to their irregular mass and stiffness distribution, and complexity of the loading conditions they need to withstand. There are other challenges in particular locations such as typhoons, hurricanes, earthquakes, sea-bed currents, and tsunami. Because offshore wind turbines have stringent Serviceability Limit State (SLS) requirements and need to be installed in variable and often complex ground conditions, their foundation design is challenging. Foundation design must be robust due to the enormous cost of retrofitting in a challenging environment should any problem occur during the design lifetime. Traditionally, engineers use conventional types of foundation systems, such as shallow gravity-based foundations (GBF), suction caissons, or slender piles or monopiles, based on prior experience with designing such foundations for the oil and gas industry. For offshore wind turbines, however, new types of foundations are being considered for which neither prior experience nor guidelines exist. One of the major challenges is to develop a method to de-risk the life cycle of offshore wind turbines in diverse metocean and geological conditions. The paper, therefore, has the following aims: (a) provide an overview of the complexities and the common SLS performance requirements for offshore wind turbine; (b) discuss the use of physical modelling for verification and validation of innovative design concepts, taking into account all possible angles to de-risk the project; and (c) provide examples of applications in scaled model tests. Sat, 29 May 2021 00:00:00 GMT http://irepo.futminna.edu.ng:8080/jspui/handle/123456789/30832 2021-05-29T00:00:00Z http://irepo.futminna.edu.ng:8080/jspui/handle/123456789/30825 Title: Developmnet of an Intelligent Road Condition Monitoring System using Citizen Sensing Technique Authors: Musa, A.; Bala, J.A.; Folorunsho, T.A.; Abbdulrahman, Hassan Shuaibu; Oloyede, M. Abstract: Road transportation is Nigeria’s most important mode of transportation, due to increase in vehicle ownership and the role of roads in economic activities. Road anomalies, which include potholes and speed bumps, impede the movement of traffic on roads. Therefore, there is a need for an intelligent system to detect these road anomalies and document them. Besides providing real-time assistance to road users and future driverless vehicles, an intelligent road information system can be used to build databases of road conditions across the country and to create road remediation strategies and schemes for costing road repairs. This paper presents the development of an intelligent, end-to-end road condition monitoring system using a citizen sensing approach. The approach was employed because it allows road users to gather road data with dedicated devices rather than installing sensors along the roadway. The system detects potholes using a deep learning-based object detection model (Tiny YOLOv4). The dataset used in validating the approach consisted of 1,265 images for training, 401 images for testing and 118 images for validation. The model had an overall precision of 77.00%, recall of 66.00%, F1-score of 71.00%, average IoU of 58.65% and mean average precision (mAP@0.50) of 69.99%. Based on the obtained results, the system demonstrated the ability to detect potholes on the road surface. Furthermore, this system establishes a critical first step towards a large-scale, cost-effective remote road monitoring infrastructure. Additionally, the use of citizen data collected by road users significantly reduces the cost of deploying the technique. Wed, 01 Jan 2025 00:00:00 GMT http://irepo.futminna.edu.ng:8080/jspui/handle/123456789/30825 2025-01-01T00:00:00Z http://irepo.futminna.edu.ng:8080/jspui/handle/123456789/30824 Title: Statistical models for porous asphalt mixtures containing pulverized surface dressed pavement material/low-density polyethylene waste. Authors: Abdulrahman, Hassan Shuaibu; Ali, Almusawi; Julide, Oner; Nasiru, Ibrahim Ahmed Abstract: (PA) mixtures typically contain a high proportion of coarse aggregates with minimal fine aggregates, along with a binder that creates ample space for water drainage. Since road construction consumes large quantities of aggregates, recycling and reusing materials have become common practices. This study focuses on developing PA by partially replacing traditional aggregates with pulverized surface-dressed pavement material (PSM) and modifying bitumen with low-density polyethylene (LDPE). The mixtures were produced using 60/70 penetration grade bitumen modified with 2%, 4%, and 6% LDPE waste and 20%, 40%, 60%, and 80% PSM. Adding LDPE waste to the bitumen altered key properties, such as the softening point, penetration, flashpoint, and ductility, resulting in a stiffer binder. Replacing aggregates with PSM reduced both stability and flow, leading to a lower Marshall quotient. Flow values for all trial mixes did not meet AAPA (2004) standards, while stability values slightly decreased as LDPE content increased from 2% to 6%. Despite this, all samples met the AAPA (2004) stability standard. The sample containing 2% LDPE and no PSM exhibited the highest Marshall quotient. Linear regression models were developed from experimental data to highlight the relationships between the measured responses and the variables. These polynomial equations demonstrated a strong correlation, indicated by high coefficients of determination. The study introduces an innovative approach by incorporating PSM and LDPE, largely unexplored in PA production, especially in Nigeria. The major societal benefits include reducing environmental pollution through plastic waste reuse, conserving natural aggregates, and promoting cost-effective construction practices. By advancing the use of recycled materials, this research supports sustainable infrastructure development while maintaining compliance with industry standards. Wed, 01 Jan 2025 00:00:00 GMT http://irepo.futminna.edu.ng:8080/jspui/handle/123456789/30824 2025-01-01T00:00:00Z http://irepo.futminna.edu.ng:8080/jspui/handle/123456789/29991 Title: HYDRAULIC CONDUCTIVITY CHARACTERISTICS OF LEACHATE - CONTAMINATEDLATERITIC SOIL Authors: Asogwa, E. O; Adie, D.B; Ibrahim, F.B; Amadi, A.A; Agbonselobho, M.O Abstract: Lateritic soil contamination due to the Leachate from Municipal Solid Waste is a major environmental problem. Landfill leachate is generated from liquids existing in the waste as it enters a landfill or from rainwater that passes through the waste within the facility. The properties and structure of a compacted liner can change with time due to changes in moisture content, capillary forces, and physico-chemical interactions with the liquid waste resulting in a reduction of the effectiveness of the liner as a barrier to contain solid and liquid waste. The changes in chemical characteristics of soils due to leachate contamination may be detrimental to the compacted soils/liner. To protect the groundwater from landfill contaminants, lateritic soil liners are widely used to impede the flow of leachate from municipal solid waste (Osinubi and Nwaiwu, 2005). A comprehensive laboratory analysis was carried out to determine the index properties, compaction characteristics and hydraulic conductivity of natural and contaminated lateritic soil. Contaminated samples were prepared by mixing the lateritic soil with varying percentage of leachate at step concentration of 0%, 25%, 50%, 75% and 100% to vary the degree of contamination. The effects of leachate on the Atterberg limit showed increase in liquid and plasticity index values with the increase in the leachate content, thus: Liquid Limit (WI) and plastic index (IP) at 0% is 51 and 23.08, at 25%(WI = 52.92, IP =26.48, at 50%( WI =53, IP =29.28), at 70% (WI =53.22, IP =32.17) at100 %( WI =54.2 and IP = 34.13). The hydraulic conductivity of the natural lateritic soil is 1.40 x 10-6cm/s and 1.30x10-7cm/s using BSL and BSH comparative efforts respectively at 0 day curing time. There is corresponding increase in the hydraulic conductivity of the lateritic soil with increase in the percentage contamination, thus: 25%( 4.75x10-6cm/s and 2.78x10-7cm/s ), 50%( 6.94x10-6cm/s and 4.52x10-6cm/s ), 75%( 7.90x10-6 cm/s and 6.10x10-7cm/s ) and finally 100%(5.44x10-6cm/s and 7.33x10-7cm/s) using BSL and BSH comparative Effort respectively. In conclusion, increase in percentage contamination of lateritic soil increases the hydraulic conductivity, liquid limit, plasticity index and optimum moisture content while maximum dry density decreases. Wed, 30 Nov 2022 00:00:00 GMT http://irepo.futminna.edu.ng:8080/jspui/handle/123456789/29991 2022-11-30T00:00:00Z