Papers by Titilayo A . OWOLABI
Proceedings of the 6th International Symposium on Reliability Engineering and Risk Management, 2018
Landslides are a major hazard in Hong Kong which can lead to loss of life, injury to people, or e... more Landslides are a major hazard in Hong Kong which can lead to loss of life, injury to people, or economic losses. This paper assesses the landslide risk in western part of Hong Kong Island under extreme rainstorms of 29%, 44%, 65% and 85% of the 24-h Probable Maximum Precipitation. The number of buildings affected and the total population inside the buildings have been identified. The vulnerability factor was evaluated as a function of travel angle and time of landslide occurrence. It was observed that the vulnerability factor increases as the travel angle increases for all the PMP levels. At 85% and 65% PMP, the occurrence of landslides and the risk they pose on buildings are much higher than those at 44% and 29% PMP. The lowest potential loss of life is observed in schools, hospitals, community centres and government buildings. The findings from this work suggest that the time of occurrence of landslides can significantly affect the distribution of potential loss of life in each building.
Authorea, Apr 29, 2020
This research work has analyzed the geotechnical characteristics of two borrow pits around Afe ba... more This research work has analyzed the geotechnical characteristics of two borrow pits around Afe babalola university. The research work was carried out by collection of soil samples from borrowpit 1 (beside Federal polytechnic, Ado-Ekiti, Nigeria) and borrowpit 2 (along Afe Babalola farm, Ado-Ekiti, Nigeria) and taken to the laboratory for soil test. The particle size analysis shows that the percentages passing number 200 British Standard sieve are 22.18% and 13.02% for borrowpits 1 and 2 respectively. Atterberg limit results show that borrow pit 2 has sandy particle sizes predominating. Hence the soil sample as a result of its particle size composition happens to be a cohesionless soil with no plasticity while pit 1 has liquid limit of 32.5%, plastic limit of 27.77%, plasticity index of 5% and shrinkage limit of 5.8%. The natural moisture content for the soil samples are 5% and 9.7% for borrowpit 1 and borrowpit 2 respectively. The specific gravity for borrowpit 1 and borrowpit 2 are 2.67 and 2.60 respectively. The soaked CBR value for the soil samples are 70% and 66%. The maximum dry density for the soil samples are 1.82Mg/m3 and 2.0Mg/m3 for borrowpit 1 and borrowpit 2 respectively. While that of Optimum moisture content are 16.24% and 13.5% for borrowpit 1 and borrowpit 2 respectively. The unconfined compressive strength (qu) for borrowpit 1 soil sample is 91.5kN/m2. The unconfined compressive strength of borrowpit 2 could not be obtained as it is a sandy material. Hence borrowpit 1 can be classified as A-2-4 material (silty or clayey gravel and sand) while borrowpit 2 can be classified as A-3 material (fine sand).
Journal of Environmental Management, 2022
Sewer networks play a pivotal role in our everyday lives by transporting the stormwater and urban... more Sewer networks play a pivotal role in our everyday lives by transporting the stormwater and urban sewage away from the urban areas. In this regard, Sewer Overflow (SO) has been considered as a detrimental threat to our environment and health, which results from the wastewater discharge into the environment. In order to grapple with such deleterious phenomenon, numerous studies have been conducted; however, there has not been any review paper that provides the researchers undertaking research in this area with the following inclusive picture: (1) detailed-scientometric analysis of the research undertaken hitherto, (2) the types of methodologies used in the previous studies, (3) the aspects of environment impacted by the SO occurrence, and (4) the gaps existing in the relative literature together with the potential future works to be undertaken. Based on the comprehensive review undertaken, it is observed that simulation and artificial intelligence-based methods have been the most popular approaches. In addition, it has come to the attention that the detrimental impacts associated with the SO are fourfold as follows: air, quality of water, soil, and business and structure. Among these, the majority of the studies' focus have been tilted towards the impact of SO on the quality of ground water. The outcomes of this state-of-the-art review provides the researchers and environmental engineers with inclusive hindsight in dealing with such serious issue, which in turn, this culminates in a significant improvement in our environment as well as humans' well-beings.
International journal of disaster risk reduction, Jun 1, 2023
Proceedings of the 7th International Symposium on Geotechnical Safety and Risk (ISGSR 2019), 2019
This research work presents the properties concrete using cassava peel ash (CPA) as a partial rep... more This research work presents the properties concrete using cassava peel ash (CPA) as a partial replacement for cement. Specific gravity, sieve analysis, density test, slump test and cube test were carried out in the concrete laboratory. Concrete cubes were cast, cured and tested at curing ages of 7, 14, 21 and 28 days using 0, 5, 10 15, and 20 percentage replacement levels. The density test showed that CFA has no significant effect on the density of the concrete. The optimum compressive strength of 17.5N/mm2 was obtained at 5% replacement at 28 days of age compared to the control of 23.6 N/mm2. The slump test results show that the workability of the concrete decreased as the CFA content increased. Water binder ratios of 0.55 0.6, 0.65 and 0.75 were used for the concrete mix 1:2:4 with varying percentage of cassava peel ash (CPA) as replacement for cement. Water binder ratio of 0.75 was found to be optimum to produce workable blended concrete. This shows that more water is needed to m...
Authorea
Geo-environmental hazards associated with abandoned borrow pits in Nigeria are on the rise and a ... more Geo-environmental hazards associated with abandoned borrow pits in Nigeria are on the rise and a major concern to citizens, environmentalists and governments. Several highway failure spots are directly linked to the action of erosion initiated by active or abandoned (inactive) borrow pits situated close to the roads. This study examines the negative environmental impacts of the continuous removal of soil from borrow pits in some areas of Ado Ekiti, Nigeria. Four borrow pits were selected; two active sites and two abandoned sites. At inception, topographical and 3-Dimensional maps of the borrow pits were drawn and modelled. The area of the borrow pits and the volume of overburden excavated soils were calculated. The soil over burden pressure at the average height of the borrow pits were measured. The active borrow pit sites were checked again after two months to know the difference in the volume of overburden removed in the pit for that period. The volume of soil removed from borrow pit 1 (Active site), 2 (Active site), 3(Abandoned) and 4 (Abandoned) are 37000 m3, 34000 m3, 114000 m3 and 81000 m3 respectively. Environmental assessment of the study area through photographs showed prevalence of landslides, erosion, flooding, vegetation removal and structural failure. The volume of soil overburden removed from the abandoned borrow pit is more than the volume extracted from the active sites, this significant change in the value of overburden removed causes significant change to the terrain of the borrow pit. Some measures were then suggested to curb the problem occurring from the uncontrolled and indiscriminate borrow pits excavation thereby improving environmental sustainability. This study serves as a basis for government to put in place laws that help protect the environment from indiscriminate mining of borrow pits.
A pervious concrete is a type of porous pavement that can be used as an infiltration process for ... more A pervious concrete is a type of porous pavement that can be used as an infiltration process for stormwater management and contains little or no fine aggregates. Pervious concrete offers one of the most cost-effective and environmentally friendly solutions available as permeable pavement in order to control uncontrolled run-off, reduce pollution and replenish groundwater. An important part of this research involves determining infiltration rate through pervious concrete sections. Approach used in the investigation included casting 64 pervious concrete cubes (1: 0:4, 1:1:4, 1:1/2:4, 1:1:5) with varying water/cement ratios. While compressive strength was carried out on the hardened concrete cubes, infiltration rate of water through the sections were determined. The infiltration rate of concrete was tested for concrete cast on different sub-grades and without sub-grade by the application of water at a constant rate to the concrete surface. Also, the properties of the sub-grade were inv...
This research project aims at evaluating the geotechnical properties of lateritic soil in Akure S... more This research project aims at evaluating the geotechnical properties of lateritic soil in Akure South, Southwestern Nigeria. In order to achieve this, six samples were collected from two borrow pits for laboratory test. Atterberg limits test, specific gravity test, sieve analysis test, moisture content test, compaction test and California bearing ratio test (CBR) and unconfined compressive strength were conducted on the soil samples in accordance with British standard code of practice (BS1377:1990), Methods of test for soils for civil engineering purposes. The particle size analysis shows that the percentages passing number 200 BS sieve are 13%, 6% and 53% for samples S1, S2 and S3 respectively. Samples S1 and S2 can be deduced as suitable for sub-grade, sub-base and base materials as the percentage by weight finer than N0 200BS test sieve is less than 35%. The Atterberg limit result shows that sample S1, S2 and S3 have sandy particle sizes predominating. Hence the soil sample as a ...
Dam Breach Modelling and Risk Disposal, 2020
Flood damage has been extremely severe in recent decades and is responsible for a greater number ... more Flood damage has been extremely severe in recent decades and is responsible for a greater number of damaging events than any other type of natural hazard. Floods are anticipated to happen more frequently in the future because of climate change, unplanned rapid urbanization, change in land use pattern, poor watershed management and declining recharge of groundwater by extension of impermeable surfaces in urban areas. Therefore, assessment of flood consequence under large storms is an important issue. This paper quantifies the elements at risk in Hong Kong under large storm scenarios with rain intensities of 29 and 85% of the 24-h Probable Maximum Precipitation (PMP). The buildings affected were obtained by overlaying flood maps and building maps in a GIS environment. The numbers of buildings of all types and exposed individuals affected by the flood under the two storm scenarios were also quantified. The results indicate that residential buildings appear to be the most vulnerable among all structures and facilities in Hong Kong and thereby may lead to the highest affected population under the two rainfall scenarios. The western part of Hong Kong Island is more susceptible to flooding as a result of its steeper slope terrain and densely populated infrastructures. Enhanced flood risk assessment methods and improved understanding about flood risk will support decision makers in decreasing damage and fatalities.
Forecast models for predicting future cost and prices of selected material, labour and equipment ... more Forecast models for predicting future cost and prices of selected material, labour and equipment components both for building and civil engineering construction activities within the study area were generated based on past cost and price data collected. Prices, wages and hiring rate data for a defined period (2000-2010) were collated and stored in a database after which they were used to generate price indices using the Laspeyres index. A univariate (single variable) time series model was used to generate a forecast of future prices of the same selected components after the raw data had been adjusted by removing the effect of inflation. Series of analysis were carried out to ensure that effect of external forces like inflation, market forces etc. were removed giving a ‘constant’ (deflated) monetary value. The model was used to generate future cost and price data with subsequent error analysis carried out to verify the accuracy of the model. The generated models were found to be good...
Informatics in Medicine Unlocked, 2020
Abstract Lassa fever is a severe hemorrhagic viral infection whose agents belong to Mastomys nate... more Abstract Lassa fever is a severe hemorrhagic viral infection whose agents belong to Mastomys natelensis. Generally, humans contract Lassa virus through exposure to food or household products that have been contaminated with the excreta of the infected rodents. Lassa fever is endemic in some West African countries including Nigeria. A basic model is proposed to examine the transmission of the disease. The proposed model is subjected to qualitative study via the theory of differential equations and the threshold quantity that denotes the dominant eigenvalue was derived using next-generation matrix approach. The basic model is further extended to an optimal control model with four controls namely, the fumigation of the environment with pesticide, the use of condom to prevent human to human transmission during sexual activities, early treatment and the use of indoor residual spray. The theory of optimal control was explored to establish the necessary conditions for curtailing the transmission of Lassa fever. Numerical simulation was conducted and the results showed that if the Lassa fever transmission and spread were to be reduced significantly in the endemic region, all the control measures must be taken with all seriousness.
This research work has analysed the geotechnical properties of a typical collapsible soil. A port... more This research work has analysed the geotechnical properties of a typical collapsible soil. A portion of the highway along Osogbo-Iwo road at chainage 4+500 (Right hand side of the road) in southwestern Nigeria has had a history of perennial failure which has necessitated a special attention and hence this study. Direct shear tests were carried out on the undisturbed samples at various normal stresses and at 0.0375mm/min , 0.375mm/min and 3.75mm/min rate of strain. The shear strength increased with increasing rate of strain with C values of 5, 8, 10
Environmental and Sustainability Indicators
Population explosion coupled with poor governance and land use planning is responsible for indisc... more Population explosion coupled with poor governance and land use planning is responsible for indiscriminate dumping of solid waste in unsuitable sites. Despite the vast availability of modern methods of siting landfills, many waste disposal methods in Akure are piled up in open sites and unsafe. Owing to this lack of effectiveness of these common methods in Akure, a better approach is adopted to enable the analysis of a number of required qualitative and quantitative issues for landfill site selection. This study is aimed at identifying suitable sites for solid waste disposal and management while considering all essential factors and rating criteria by integrating GIS with multi-criteria decision analysis (MCDA) in Akure, Ondo State. Standards for siting landfill formulated by the Environment Protection Agency (EPA) were employed in this study. The criteria that are considered herein are land use, slope, distance to drainage, distance to linear features, soil, geology, distance to the residence and road accessibility. These criteria were assigned fuzzy membership classes based on their importance in siting landfill. The fuzzy members of all criteria were overlaid to generate the final landfill site suitability map which was classified into five: not suitable (34.1%), less suitable (50.4%), moderately suitable (0.3%), suitable (0.02%) and highly suitable (15.5%). The Analytical Hierarchy Process (AHP) technique was employed in the selection of the landfill site with reverence to multiple criteria and the fuzzy membership classes in accordance with the standards of the EPA. The result of this study serves as guide for further field survey.
Journal of Water and Climate Change
Soil erosion and mass movement processes spread across Anambra State in Nigeria, therefore making... more Soil erosion and mass movement processes spread across Anambra State in Nigeria, therefore making management and conservation techniques expensive and difficult in execution across the entire state. This study employed the Revised Universal Soil Loss Equation (RUSLE) model with the integration of geographic information system (GIS) and remote sensing techniques to assess the risk of soil erosion and hotspots in the area. Remotely sensed data such as Landsat 8 imagery, Shuttle Radar Topography Mission (SRTM) imagery, Era-Interim coupled with world soil database were used as digital data sources for land use map, digital elevation model, rainfall and soil data, respectively, to generate the Universal Soil Loss Equation (USLE) parameters. The results indicated vulnerability levels in low, medium and high cover areas of 4,143.62 (91%), 332.29 (7%) and 84.06 (2%) km2, respectively, with a total soil loss between 0 and 181.237 ton/ha/yr (metric ton per hectare per year). This study reveal...
Informatics in Medicine Unlocked, 2020
Lassa fever is a severe hemorrhagic viral infection whose agents belong to Mastomys natelensis. G... more Lassa fever is a severe hemorrhagic viral infection whose agents belong to Mastomys natelensis. Generally, humans contract Lassa virus through exposure to food or household products that have been contaminated with the excreta of the infected rodents. Lassa fever is endemic in some West African countries including Nigeria. A basic model is proposed to examine the transmission of the disease. The proposed model is subjected to qualitative study via the theory of differential equations and the threshold quantity that denotes the dominant eigenvalue was derived using next-generation matrix approach. The basic model is further extended to an optimal control model with four controls namely, the fumigation of the environment with pesticide, the use of condom to prevent human to human transmission during sexual activities, early treatment and the use of indoor residual spray. The theory of optimal control was explored to establish the necessary conditions for curtailing the transmission of Lassa fever. Numerical simulation was conducted and the results showed that if the Lassa fever transmission and spread were to be reduced significantly in the endemic region, all the control measures must be taken with all seriousness.
Environmental and Sustainability Indicators, 2019
Population explosion coupled with poor governance and land use planning is responsible for indisc... more Population explosion coupled with poor governance and land use planning is responsible for indiscriminate dumping of solid waste in unsuitable sites. Despite the vast availability of modern methods of siting landfills, many waste disposal methods in Akure are piled up in open sites and unsafe. Owing to this lack of effectiveness of these common methods in Akure, a better approach is adopted to enable the analysis of a number of required qualitative and quantitative issues for landfill site selection. This study is aimed at identifying suitable sites for
solid waste disposal and management while considering all essential factors and rating criteria by integrating GIS with multi-criteria decision analysis (MCDA) in Akure, Ondo State. Standards for siting landfill formulated by the Environment Protection Agency (EPA) were employed in this study. The criteria that are considered herein are land use, slope, distance to drainage, distance to linear features, soil, geology, distance to the residence and road accessibility. These criteria were assigned fuzzy membership classes based on their importance in siting landfill. The fuzzy members of all criteria were overlaid to generate the final landfill site suitability map which was classified into five: not suitable (34.1%), less suitable (50.4%), moderately suitable (0.3%), suitable (0.02%) and highly suitable (15.5%). The Analytical Hierarchy Process (AHP) technique was employed in the selection of the landfill site with reverence to multiple criteria and the fuzzy membership classes in accordance with the standards of the EPA. The result of this study serves as guide for further field survey.
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Papers by Titilayo A . OWOLABI
solid waste disposal and management while considering all essential factors and rating criteria by integrating GIS with multi-criteria decision analysis (MCDA) in Akure, Ondo State. Standards for siting landfill formulated by the Environment Protection Agency (EPA) were employed in this study. The criteria that are considered herein are land use, slope, distance to drainage, distance to linear features, soil, geology, distance to the residence and road accessibility. These criteria were assigned fuzzy membership classes based on their importance in siting landfill. The fuzzy members of all criteria were overlaid to generate the final landfill site suitability map which was classified into five: not suitable (34.1%), less suitable (50.4%), moderately suitable (0.3%), suitable (0.02%) and highly suitable (15.5%). The Analytical Hierarchy Process (AHP) technique was employed in the selection of the landfill site with reverence to multiple criteria and the fuzzy membership classes in accordance with the standards of the EPA. The result of this study serves as guide for further field survey.
solid waste disposal and management while considering all essential factors and rating criteria by integrating GIS with multi-criteria decision analysis (MCDA) in Akure, Ondo State. Standards for siting landfill formulated by the Environment Protection Agency (EPA) were employed in this study. The criteria that are considered herein are land use, slope, distance to drainage, distance to linear features, soil, geology, distance to the residence and road accessibility. These criteria were assigned fuzzy membership classes based on their importance in siting landfill. The fuzzy members of all criteria were overlaid to generate the final landfill site suitability map which was classified into five: not suitable (34.1%), less suitable (50.4%), moderately suitable (0.3%), suitable (0.02%) and highly suitable (15.5%). The Analytical Hierarchy Process (AHP) technique was employed in the selection of the landfill site with reverence to multiple criteria and the fuzzy membership classes in accordance with the standards of the EPA. The result of this study serves as guide for further field survey.
south-eastern part of the country. It has attracted the interest of professionals (geographers, cartographers, geomorphologists, chemists,
engineers, etc) who are interested in its studies (causes and effects)
and has been of great concern to affected communities who are
interested in its solution (control and minimization). Soil erosion
remains the world’s biggest environmental problem, threatening
sustainability of both plant and animal in the world