Oluwole Agbede

Geotechnical Investigation into the Causes of Cracks in Building: A Case Study of Dr. Egbogha Building, University of Ibadan, Nigeria

The study examined the geotechnical properties of soil supporting Egbogha building that has been ... more The study examined the geotechnical properties of soil supporting Egbogha building that has been revealing deep cracks around its wall. Soil samples were collected around the building for laboratory study. The properties determined were natural moisture content, particle size, Atterberg limits, compaction, and consolidation. The results of the tests show that the site is dominated with poorly graded soil with specific gravity (2.482.63), liquid limit (26%-53%), optimum moisture content (13.50%-26.20%) and maximum dry density (1.50kN/m 3 -1.94kN/m 3 ). According to the soil settlement estimated, the result indicated insignificant settlement at 1.5m depth. According to the classification of potential swell of the soil, the soil has medium potential for shrinkage or swelling. This could be attributed to high clay content in the soil. Hence, the soil has tendency for expansion. This therefore suggested that the cause of the noticed cracks on the structure under study could be as a resul...

Optimization of Singly Reinforced Beam Design Using Simulated Annealing

IOP Conference Series: Materials Science and Engineering, 2021

This paper investigated the optimization of a singly reinforced concrete beam using the Simulated... more This paper investigated the optimization of a singly reinforced concrete beam using the Simulated Annealing. The code provisions usually lead to the overestimation of reinforcement and thus an expensive cost of construction. The optimized design reduces the cost significantly. There are many methods of structural optimization but Simulated Annealing has been found to very efficient for constrained optimization of reinforced concrete beam design. The variables considered are the width, depth, compression steel, tension steel, and cost while the constraints are steel ratios, ultimate moment of resistance, maximum and minimum areas of reinforcements Materials costs are considered as the objective function. It is demonstrated that using the concrete compressive strength of 25MPa, Simulated Annealing can be used to optimize the design of concrete beams effectively. The results also indicate that the complications connected to the actual and genuine evaluation of costs of structures and t...

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Impact of Firing Temperature on Compressive Strength Characteristics of Lateritic Bricks

This study assessed the impact of firing temperature on compressive strength of lateritic bricks.... more This study assessed the impact of firing temperature on compressive strength of lateritic bricks. Twenty lateritic bricks samples of size 290mm x 140mm x 100mm were produced from the lateritic soil sample collected from a borrow pit along Ibadan-Lagos expressway, Southwestern, Nigeria. The geotechnical characteristics and classification of the lateritic soil sample were established. The bricks produced were fired at temperature 0 o C to 950 o C at 150 o C interval after 28days of curing. The compressive strength of the fired bricks was determined. The result of geotechnical test carried out on the soil sample showed that the soil is laterite having a clay content <30%, extremely low gravel <10% and sand content of 83.33%. The Atterberg's limit test gave the liquid limit as 48%and plastic index 18.78%. The soil has natural moisture content and specific gravity of 34.92% and 2.64 respectively. The result further indicated that weight of the brick before and after firing is i...

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System Dynamics Modeling of Dumpsite Leachate Control

Leachate pollution from landfills is a major source of environmental hazard in many Nigerian muni... more Leachate pollution from landfills is a major source of environmental hazard in many Nigerian municipalities and there is the need to mitigate its effects. The aim of this study is to examine the leachate pollution and determine the effec-tiveness of liner system in leachate management of dumpsites in Ogbomosoland. The method of modeling using princi-ples of system dynamics was employed to determine the interrelationships of leachate generation components for 50 years. Causal loops indicating the linkage of population, economic status, waste generation per capita and weather con-ditions to wastes and leachate generation were developed. A set of state model equations for Gas Produced (Gp), Pre-cipitation (Pt), Degradation water-loss (Wg), Leachate Quantity (LQn), were formulated. Leachate management strate-gies of liner systems were studied, and the effectiveness of Compacted Clay (CC), High Density Polyethylene (HDPE),

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Sensitivity Analysis of Population in the Generation of Hazardous and Non-Harzardous Wastes, and Gas from Dumpsites of Ogbomosoland in Nigeria

International Journal of Engineering and Technology Innovation, 2013

This paper applies the principles of system dynamics modeling in studying the pattern of populati... more This paper applies the principles of system dynamics modeling in studying the pattern of population changes and the corresponding non-hazardous wastes and gas being generated from the dumpsites of Ogbomosoland, Nigeria. The five (5) Local government Areas (LGAs) of Ogbomosoland were categorized as Urban (Ogbomoso North and Ogbomoso South) and Rural (Oriire, Ogo Oluwa and Suurulere) based on the size, population of residents, consumption pattern and socio-economic activities of the area. A sensitivity analysis of the simulated variables i.e the population, wastes and gas, was performed by employing the developed model results. Findings showed that the wastes and gas increased with the increased population in the 1000 years period. Also, gas production exceeds wastes generation rates for the rural LGAs in all cases. After a 25 years benchmark, when the simulated population of the urban and rural LGAs are respectively 303,411 and 344,735, the rates of waste generation are 3.33x106 and ...

Gaussian Naïve Bayes Classification Algorithm for Drought and Flood Risk Reduction

Springer Transactions in Civil and Environmental Engineering

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Electrochemical Soil Stabilization and Verification

Geotechnical and Geological Engineering

ElectroChemical treatment (ECT) has been applied for the in situ chemical stabilization soft clay... more ElectroChemical treatment (ECT) has been applied for the in situ chemical stabilization soft clay soils. A possibility during ECT is mineral dissolution and re-deposition which can cause microstructural changes affecting the engineering behavior of clay soils. Additionally, during ECT the success of depositing the stabilizing chemicals in the tight clay matrices may be hindered by process parameters, such as electrode reactions. A simple monitoring method was tested in the laboratory to track the evolution of intended ECT stabilization for quick assessment and potential control of the process. Calcium and phosphate ions were injected separately and then together into kaolin clay under a constant voltage gradient at varying durations. Calcium hydroxide and phosphoric acid were used as the feed electrolytes in the anolyte and catholyte, respectively. The ECT triggered stabilization was diagnosed by monitoring the evolution of clay soil stiffness. The shear wave velocity (V s) and the small strain modulus (G max) of the treated specimens were monitored using bender elements (i.e., piezoelectric transceivers). Finally, changes in the microstructure of the clay were analyzed using comparative XRD and SEM scans of pre-and posttreatment specimens. The analysis showed that electro-migration of calcium ions occurred but did not result in the expected cementation within the clay soil because of low pH hindering formation of calcium hydrates. In contrast, the G max of the samples treated with phosphate ions increased at the cathode and the middle sections of the clay specimens by 10 and 20%, respectively. While SEM results did not reveal discernible micro-structural changes in the treated clay matrix, the XRD result showed discernable changes in some elemental peaks, indicating chemical accumulation. The nondestructive diagnostic method was beneficial and showed promise for possible field application for transient assessment of the efficacy of ECT stabilization of clay soils.

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Plasticity modification of a tropical laterite by electrochemical stabilization

Electrochimica Acta

Effect of selected factors on the current flow and voltage loss at electrodes during electrochemical treatment of a laterite

Ife Journal of Science, 2014

In this paper, laboratory scale study was conducted to investigate the current flow and voltage l... more In this paper, laboratory scale study was conducted to investigate the current flow and voltage loss at the electrodes in the electrochemical treatment of a tropical laterite. Three different tests using calcium chloride (CC) as anolyte and sodium chloride (SC) as catholyte (NC); SC as anolyte and Phosphoric acid (PA) as catholyte (NP) and CC as anolyte and PA as catholyte (CP) were conducted at two different voltage gradients of 1 and 2 V/cm. Perforated Titanium sheet were used as the electrodes. Current flow and voltage at the electrodes were measured using standard methods. Effects of selected factors on the current flow and voltage losses were onitored. Energy consumption analysis was provided. The study revealed that the highest currents were consistently generated in CP tests while the lowest current was generated in NC tests. The highest voltage losses of about 75% were recorded in 40NC and 40CP tests, although, the conductivity of CC and SC kept increasing during the test. I...

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Wetland systems: a cheaper and efficient treatment option for food processing waste in Africa

The study investigates an alternative wastewater treatment system for the food and beverage indus... more The study investigates an alternative wastewater treatment system for the food and beverage industry in Africa. A subsurface flow wetland system was designed and compared with a combination of anaerobic and aerobic bioreactor installed for a brewery in Nigeria. The cost of the designed wetland system is 33% of the cost of installed bioreactor. The waste characteristics for the designed subsurface flow constructed wetland after treatment falls within the USEPA threshold while that of the installed Bioreactor, are above. In addition, the treatment efficiency of the designed subsurface flow constructed wetland for controlling parameters; BOD, TSS and Faecal Coliform are 96.83%, 88.42% and 96.29% respectively while that of the UASB reactor, are 62.94%, 15.36% and 63.81%. Hence, the designed subsurface flow constructed wetland is more efficient in the removal of BOD, TSS and Faecal Coliform and could be an excellent alternative for the food and beverage industry in Africa.

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Groundwater availability in south western Nigeria

In urban water supply the importance of groundwater has become very obvious to most water supply... more In urban water supply the importance of groundwater has become very obvious to most water supply agencies of the State Governments, thereby resulting in a tremendous increase in well drilling activities. This paper therefore provides a review of available groundwater information as well as the geological setting of Southwestern Nigeria. The degree of groundwater exploitation in each of the hydro-geological units in the study area is assessed in relation to their hydraulic characteristics. The results of the statistical analysis show that the behaviour of the borehole characteristics is erratic and unpredictable, and that generally the yields from the productive boreholes are very poor. The contribution of the geology of the area to this erratic behaviour and low yields is also discussed.

Electrochemical Soil Stabilization and Verification

Geotechnical and Geological Engineering, 2017

ElectroChemical treatment (ECT) has been applied for the in situ chemical stabilization soft clay... more ElectroChemical treatment (ECT) has been applied for the in situ chemical stabilization soft clay soils. A possibility during ECT is mineral dissolution and re-deposition which can cause micro-structural changes affecting the engineering behavior of clay soils. Additionally, during ECT the success of depositing the stabilizing chemicals in the tight clay matrices may be hindered by process parameters, such as electrode reactions. A simple monitoring method was tested in the laboratory to track the evolution of intended ECT stabilization for quick assessment and potential control of the process. Calcium and phosphate ions were injected separately and then together into kaolin clay under a constant voltage gradient at varying durations. Calcium hydroxide and phosphoric acid were used as the feed electrolytes in the anolyte and catholyte, respectively. The ECT triggered stabilization was diagnosed by monitoring the evolution of clay soil stiffness. The shear wave velocity (Vs) and the ...

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Health and safety management practices in the Nigerian construction industry: A survey of construction firms in South Western Nigeria

Despite the relevance of the construction sector in developing countries, the industry continues ... more Despite the relevance of the construction sector in developing countries, the industry continues to record unacceptable levels of accidents and fatalities. The situation is no different in Nigeria where health and safety (HS and communicating HS site inductions for workers; rewarding workers for safe work behaviour; assessing the competence of workers and subcontractors; keeping incident records; investigating the causes of incidents, accidents and near misses; providing training programmes for HS and undertaking risk assessment for work packages or operations before they start. Overall, the research shows a gloomy outlook of the implementation of practices in key elements of H&S management (i.e. policy, planning, organising, risk assessment, implementing, performance measurement, and auditing). Contractors, relevant state authorities and industry bodies therefore ought to take collective action to improve H&S management by contractors.

Performance Evaluation of Machine Learning Models in Predicting Dry and Wet Climatic Phases

Water resource and environmental engineers need accurate information in harnessing water for dive... more Water resource and environmental engineers need accurate information in harnessing water for diverse uses, therefore it is expedient to accurately predict dry and wet climatic phases in order to ensure optimum water resource planning and management. This study examined the applicability of machine learning models for the prediction of extreme dry and wet conditions in Minna, North Central Nigeria. Recorded rainfall, maximum temperature, minimum temperature, relative humidity, wind speed, sunshine hours and estimated potential evapotranspiration were used as predictors in the machine learning models, while hydrological extremes estimated from standardized precipitation index (SPI) served as a response variable. The performance of Support Vector Machine (SVM) based on different kernel types and Artificial Neural Network (ANN) based on different network structures were assessed for the prediction of the different phases of the climate of the study area. The study showed that while norm...

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Influence of Calcium Sulphate on Subsoil Cohesion and Angle of Friction

3 Abstract: Soil composition in urban environment is changing daily due to human and industrial a... more 3 Abstract: Soil composition in urban environment is changing daily due to human and industrial activities. Organic and inorganic materials are added to soil at uncontrolled rate. The research focused on the influence of calcium sulphate salt on the shear strength properties of subsoil. Twenty one samples of subsoil were obtained from a borrow pit in Ibadan, Nigeria. The samples were subjected to 0, 10, 30, 50 4 and 70 g/l concentrations of CaSO salt solution for 364 days. During the curing period, soil samples 4 chemical properties such as cation exchange capacity CEC, exchangeable calcium Ca and sulphate SO 2 + 2- were monitored. Also, their cohesion and angle of friction properties were measured. Using multiple linear regression statistical analysis tool, predictive model for generating the subsoil cohesion and angle of friction was developed and validated. The laboratory results showed that there were initial increments in 4 soil angle of friction and cohesion due to presence of...

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Gaussian Naïve Bayes Classification Algorithm for Drought and Flood Risk Reduction

There exist general speculations and scientifically proven indications that climate-induced hazar... more There exist general speculations and scientifically proven indications that climate-induced hazards will increase due to climate change and large-scale variability. Consequently, intelligent data analytic models are increasingly harnessed as decision support tools. This chapter presents an intelligent data analytic technique for predicting several magnitudes of droughts and floods, as well as conditions that necessitate their occurrence based on independent atmospheric variables of North Central Nigeria. The chapter builds knowledge on the Gaussian Naive Bayes classification. Monthly climate data (1960–2015) which consists of rainfall, maximum and minimum temperature, relative humidity, wind speed, sunshine duration, potential evapotranspiration, and Standardized Precipitation Index (SPI) were employed as predictor variables, while seven SPI classes were employed as the response variable. Seventy percent (70%) of the dataset was used to train the models while the remaining 30% was u...

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Selection of flood frequency model in Niger Basin using maximum likelihood method

Towards an Integration of Engineering, Design and Management Approaches, 2008

... GA Bolaji Department of Civil Engineering, University of Agriculture, Abeokuta OA Agbede Depa... more

Selection of flood frequency model in Niger Basin using maximum likelihood method

Water and Urban …, 2008

... GA Bolaji Department of Civil Engineering, University of Agriculture, Abeokuta OA Agbede Depa... more

System Dynamics Modeling of Dumpsite Leachate Control in Ogbomosoland, Nigeria

Journal of Environmental …, 2012

Leachate pollution from landfills is a major source of environmental hazard in many Nigerian muni... more Leachate pollution from landfills is a major source of environmental hazard in many Nigerian municipalities and there is the need to mitigate its effects. The aim of this study is to examine the leachate pollution and determine the effectiveness of liner system in leachate management of dumpsites in Ogbomosoland. The method of modeling using principles of system dynamics was employed to determine the interrelationships of leachate generation components for 50 years. Causal loops indicating the linkage of population, economic status, waste generation per capita and weather conditions to wastes and leachate generation were developed. A set of state model equations for Gas Produced (G p), Precipitation (P t), Degradation water-loss (W g), Leachate Quantity (LQ n), were formulated. Leachate management strategies of liner systems were studied, and the effectiveness of Compacted Clay (CC), High Density Polyethylene (HDPE), Low Density Polyethylene (LDPE), Geosynthetic Clay (GC), Silt (SI), Sandy loam (SL), and Sand (SA) liners were examined. A user-friendly computer program for estimating leachate generation per time and breakthrough time for liners was then developed. The results showed that a direct relationship exists between leachate and G p , P t , W g and LQ n. Average leachate breakthrough times for the liners, in years, were CC (41.5), HDPE (14.0), LDPE (10.0), GC (1.1), SI (0.1), SL (0.01), and SA (0.00002). In conclusion, dumpsite leachate pollution was established as having negative effects on the groundwater resource. Compacted Clay liner is therefore recommended for use in curtailing its menace.

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Optimization of Doubly Reinforced Beam Design Using Simulated Annealing

Journal of Engineering Studies and Research

The optimization of the doubly reinforced concrete beam was investigated in this paper using the ... more The optimization of the doubly reinforced concrete beam was investigated in this paper using the simulated annealing. Materials costs are considered as the objective function. The variables are the width, depth, compression steel, tension steel and cost. The constraints are the ultimate moment of resistance, compression/tension-steel ratio, minimum and maximum area of reinforcements. At the concrete compressive strength of 25 MPa, it is demonstrated that simulated annealing method can be used to optimize the design of concrete beams.

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