scholarly works

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A preliminary evaluation of the impact of covid-19 on public transportation in Ibadan metropolis: a case study of Ibadan North local government
(Nigerian Society of Engineers, 2020-09) Okunlola, O.; Akintayo, F.O.
A number of measures have been put in place by different governments to combat the spread of Covid-19 virus. The virus has affected all forms of transportation. This paper is a preliminary study to evaluate the impact of Oyo State government lockdown measures on public transportation in Ibadan North Local Government Area between March and June 2020. Seven factors affecting public transportation as identified from literature include: availability of service, cost of service, comfortability safety /social distancing, parking difficulties and rate of accidents. Structured questionnaires were administered to purposively selected road users. The level of importance of each factor was determined and ranked by Relative Importance Index (RII). The study shows that there was a significant reduction in travel demand which in turn caused a significant increase in cost of transportation and waiting time for commuters.
A simple trafic flow simulator for two-lane highways
(University of Ibadan, Ibadan, Nigeria, 2012) Akintayo, F. O.; Agbede, O.
The highway network is an common feature on highways in many cities of the world. Including Ibadan, Nigeria. Previous studies have shown that several mathematical traffic flow models developed to analyse congestion cannot be easily generalized or adapted to varying situation. A simple traffic flow simulator was developed in the paper to stimulate flow for different congestion seanarios by varying the minimum and maximum headways if vehicles. Comparison of simulated and field values for a heavily trafficked highway in Ibadan metropolis produced an error of 35 % at high vehicular interaction
Ameliorating urban traffic congestion for sustainable transportation
(IOP Publishing, 2020) Busari, A. A.; Loto, R. T.; Ajayi, S. O.; Odunlami, O.; Akintayo, F. O.; Oyesomi, K.; Olawuyi, O.
Population, ownership of vehicles and economic growth are increasing at a geometric rate. Invariably, this will lead to an increase in traffic volume and the demand for limited road infrastructures. These has generated a lot of constraint on the few available road infrastructures in most developed and developing nations of the world. One of the consequences of this, is traffic congestion. This arises when the road system approaches vehicle capacity. Although governments and policy makers may never be able to eliminate road congestion, there are several ways cities and states can move to curb it. Hence, this review of literature assessed the myriad effect of traffic congestion, with focus on the economic and environmental impact. Additionally, long- and short-term measures to reduce the menace in 2030 were evaluated. This was done by assessing the relevant literature on the topic. The outcome of the review revealed that increase in income and living standard favours the ownership of automobiles thereby increasing traffic congestion. Households that reside in areas with compact, mixed land use own fewer vehicles, make fewer vehicle trips, therefore mixed land use should be encouraged in urban development. Additionally, level of Service (LOS) is another factor that affects traffic congestion and traffic crashes. The outcome of this review will aid the government and policy makers on the appropriate tool to adopt and the draw backs in a bid to reduce this menace now and in the foreseeable future
Analysis and Design of a Fully Submerged Underground Water Tank Using the Principle of Beam on Elastic Foundations
(2015) Ajagbe W.O; Ilugbo E.O; Labiran J.O; Ganiyu A.A.
The basic requirement in the design of reinforced water tank is to ensure it is crack free. This research studied the analysis and design of a fully submerged underground reinforced concrete water tank using the principle of beam on elastic foundations. To achieve this, a Microsoft Excel Spreadsheet Design and Analysis Program (MESDAPro) was generated for quick assessment of various moments of the tank, geometrical features and soil conditions for both full and empty conditions of the tank. It was observed that the wall moments, moment at base of wall and base slab moment decreases with increase in soil sub-grade modulus at constant capacity, height and breadth of the tank. However, wall moments, moment at base of wall and base slab moment increases with increase in height of the tank at constant value of sub-grade modulus, tank capacity and breadth. In all the examined cases, the moments obtained are higher when the tank is considered empty than when considered full
Analysis and Design of Intersection for Improved Traffic flow at Awolowo Junction, Bodija Ibadan, Nigeria
(Department of Civil Engineering, University of Ibadan, Ibadan, Nigeria, 2019-12) Adigun, T.; Okunlola, O.; Akintayo, F. O.
Traffic Congestion is inevitable for residents of economically dynamic cites therefore city authorities have to devise means of managing congestion to ease commuters of constrains imposed upon them by traffic congestion. The need for improvement of traffic flow at Awolowo Junction Bodija Ibadan is germane due to traffic congestion at this intersection. The aim of this study is to improve traffic flow at Awolowo Junction Bodija Ibadan. Traffic survey was carried out at the intersection, the peak hour factor and the design hourly volume were determined then the saturation flow rate and the cycle length (using the concept of volume-to-capacity ratio) were determined following the steps outlined in the Highway Capacity Manual, thereafter the yellow interval and the green times were computed. The peak hour was between 4:00 pm - 5:00 pm with a flow of 2989 vehicles per hour and a factor of 0.94 with design hourly volume of 539, 1464 and 1177 vehicles per hour for North, West and East approach respectively. The data collected was checked against the traffic signal warrants of the Manual on Uniform Traffic Control Device and yielded positive result with warrant 3. The saturation flow rate was computed to be 2618, 4320 and 3913 vehicles per hour for the North, West and East approach respectively with a flow ratio of 0.21, 0.34 and 0.3 for North, West and East Approach respectively. A pre-timed traffic control signal was designed to improve traffic flow at Awolowo Intersection of UI/secretariat Road.
ANALYSIS OF PRE-CAST WAFFLE SLABS USING YIELD LINE AND RANKINE GRASHOFF THEORIES
(2012-09) AKINYELE, J. O.
Failure in pre-cast waffle slabs can be attributed to factors like analytical error, poor handling during transportation and placement which factors often lead to partial/total failure of slabs. The conventional method of analysing waffle slabs focuses on the ribs, while the slab portions at the top are avoided. This has led to under reinforcement and subsequent failure of the slab portions that are usually in direct contact with loads. In this study, a method that incorporates both the slab and rib portions in the analysis of pre-cast waffle slabs was therefore developed. Yield Line and Rankine Grashoff Theories (YLRGT) were combined for the analysis of pre-cast waffle slab. Six physical models of waffle slab were developed, each having five replicates, with the following dimensions: W1 (1353 x 430 x 58 mm), W2 (900 x 300 x 50 mm), W3 (1085 x 430 x 58 mm), W4 (407 x 364 x 50 mm), W5 (1312 x 300 x 58 mm) and W6 (860 x 360 x 50mm). Solid slabs of the same size and number designated S1, S2, S3, S4, S5 and S6 served as control. These models were validated using the slabs by testing for failure loads, deflections and crack width. Each slab was subjected to incremental load of 1.0 kN until failure occurred. Maximum bending moments were obtained for slab and rib portions using YLRGT, a finite element based method called ETABS was also used to analyse the slabs and results obtained were subjected to statistical analysis using ANOVA at p= 0.05. The YLRGT analysis of the various physical models (slab portion, transverse and longitudinal ribs) yielded the following bending moments: W1 (5526.0, 34.5, 918.3) Nm, W2 (1122.0, 279.2, 36.5) Nm, W3 (2880.0, 27.2, 619.9) Nm, W4 (590.0, 171.9, 160.9) Nm, W5 (947.0, 37.0, 4.4) Nm and W6 (1276.0, 90.4, 36.2) Nm respectively. The ETABS combined both slab and ribs giving W1 (4729.0) Nm, W2 (581.0) Nm, W3 (3338.0) Nm, W4 (733.0) Nm, W5 (851.0) Nm and W6 (686.0) Nm. Deflections at failure for waffle slab were smaller compared to solid slabs: (W1 = 1.19 and S1 =3.56) mm, (W2 = 3.64 and S2 =9.28) mm, (W3 = 3.90 and S3 =7.44) mm, (W5 = 8.17 and S5 =12.18) mm, (W6 = 3.29 and S6 =3.89) mm with the exception of W4 (6.60 mm) and S4 (6.44mm), where deflection of waffle slab was higher than that of solid slab. Mean deflection of S1 was significantly higher than W1, while S2 was significantly higher than W2. Average crack width for waffle (0.48 mm) and solid slabs (0.99 mm) were significantly different. High crack width in solid slab indicated lower shear strength. The Yield Line and Rankine Grashoff Theories have facilitated the accurate analysis of pre-cast waffle slabs by separating the slab and rib portions.
ANALYSIS OF PRE-CAST WAFFLE SLABS USING YIELD LINE AND RANKINE GASHOFF THEORIES
(2012-09) AKINYELE, J.o
Failure in pre-cast waffle slabs can be attributed to factors like analytical error, poor handling during transportation and placement which factors often lead to partial/total failure of slabs. The conventional method of analyzing waffle slabs focuses on the ribs, while the slab portions at the top are avoided. This has led to under reinforcement and subsequent failure of the slab portions that are usually in direct contact with loads. In this study, a method that incorporates both the slab and rib portions in the analysis of pre-cast waffle slabs was therefore developed. Yield Line and Rankine Grashoff Theories (YLRGT) were combined for the analysis of pre-cast waffle slab. Six physical models of waffle slab were developed, each having five replicates, with the following dimensions: W1 (1353 x 430 x 58 mm), W2 (900 x 300 x 50 mm), W3 (1085 x 430 x 58 mm), W4 (407 x 364 x 50 mm), W5 (1312 x 300 x 58 mm) and W6 (860 x 360 x 50mm). Solid slabs of the same size and number designated S1, S2, S3, S4, S5 and S6 served as control. These models were validated using the slabs by testing for failure loads, deflections and crack width. Each slab was subjected to incremental load of 1.0 kN until failure occurred. Maximum bending moments were obtained for slab and rib portions using YLRGT, a finite element based method called ETABS was also used to analyse the slabs and results obtained were subjected to statistical analysis using ANOVA at p= 0.05. The YLRGT analysis of the various physical models (slab portion, transverse and longitudinal ribs) yielded the following bending moments: W1 (5526.0, 34.5, 918.3) Nm, W2 (1122.0, 279.2, 36.5) Nm, W3 (2880.0, 27.2, 619.9) Nm, W4 (590.0, 171.9, 160.9) Nm, W5 (947.0, 37.0, 4.4) Nm and W6 (1276.0, 90.4, 36.2) Nm respectively. The ETABS combined both slab and ribs giving W1 (4729.0) Nm, W2 (581.0) Nm, W3 (3338.0) Nm, W4 (733.0) Nm, W5 (851.0) Nm and W6 (686.0) Nm. Deflections at failure for waffle slab were smaller compared to solid slabs: (W1 = 1.19 and S1 =3.56) mm, (W2 = 3.64 and S2 =9.28) mm, (W3 = 3.90 and S3 =7.44) mm, (W5 = 8.17 and S5 =12.18) mm, (W6 = 3.29 and S6 =3.89) mm with the exception of W4 (6.60 mm) and S4 (6.44mm), where deflection of waffle slab was higher than that of solid slab. Mean deflection of S1 was significantly higher than W1, while S2 was significantly higher than W2. Average crack width for waffle (0.48 mm) and solid slabs (0.99 mm) were significantly different. High crack width in solid slab indicated lower shear strength. The Yield Line and Rankine Grashoff Theories have facilitated the accurate analysis of pre-cast waffle slabs by separating the slab and rib portions.
ANALYSIS OF TRAFFIC FLOW ON SELECTED TWO-LANE HIGHWAYS IN IBADAN METROPOLIS
(2011-09) AKINTAYO, F.O.
Traffic congestion is a common feature on highways in many cities of theworld, including Ibadan, Nigeria. Previous studies have shown that several mathematical traffic flow models developed to analyse congestion cannot be easily generalised or adapted to varying situations. In addition, validation errors of some models are as high as 60.0 %. In pursuit of the objective of minimising traffic congestion in parts of the Ibadan metropolis, headway simulation models were developed for the analysis of flow on some selected two-lane highways characterised by heavy traffic. Traffic survey was conducted on three purposively selected heavily-trafficked two-lane highways (Total Garden-Agodi Gate, J Allen-Oke Bola and Odo Ona-Apata) in the Ibadan metropolis. Headway modelling approach incorporating the prevailing mroadway, traffic and control conditions was developed. Field data were captured on the three roads with a camcorder between 7.00 a.m. and 6.00 p.m. for a period of six months as specified in the Highway Capacity Manual. Comparison of the modelling result and field headway data were carried out using Kolmogorov-Smirnov (KS) test (p = 0.05). A traffic flow simulator was developed to simulate the different congestion scenarios by varying the minimum and maximum headways. Capacity analysis and validation of the results were carried out using ANOVA methods. Average vehicular flow of 715 ± 3, 970 ± 5 and 1118 ± 9 vph per lane on Total Garden-Agodi Gate, J Allen-Oke Bola and Odo Ona-Apata roads respectively. Eighteen hyperbolic headway scenarios were produced and the highest coefficient of correlation (R2 = 0.92) was recorded at 90 percentile while 0.18, 0.36, 0.50, 0.71, 0.82, and 0.79 were obtained at 1, 10, 30, 50, 70, and 100 percentiles respectively. There was no significant difference between theoretical and field data using Kolmogorov- Smirnov (KS) test (p < 0.05). Also, a total number of 171 congestion scenarios were generated using the traffic flow simulator. Traffic flow varied between 204 and 2376 pcu per lane while headways varied between 1 and 18 seconds. The capacity analysis produced approximated maximum flow rates of 1850, 2865 and 2881 pcu in the two directions of travel for Total Garden-Agodi Gate, J Allen-Oke Bola and Odo Ona- Apata roads respectively. The capacity of Total Garden-Agodi Gate was within the recommended maximum value of 2800 pcu in the two directions of travel for two-lane highways. The results for J Allen-Oke Bola and Odo Ona-Apata roads showed that an additional lane will be required in each direction of travel. The validation of the models on the dualised J Allen-Oke Bola road showed that congestion can be reduced by about 55.0 %. A maximum validation error of 35.0 % was obtained. The traffic flow simulator developed successfully simulated the traffic situations on the selected highways. The analysis of the flow yielded results that could ameliorate traffic congestion on the selected two-lane highways in the Ibadan metropolis.
Appropriate Simulation Technique for Complete Single-Bolt Shear Connection Shear-Out Tensile Properties and Fracture Behavior Predictions (2
(2019) Adewole K.K.; Ajagbe W.O.
This paper presents the finite element (FE) predictions of the complete S235, S690, Q550D, Q690D and Q890D steel grades steel sheet single-bolt shear connections shear-out (SBSCSO) behavior (tensile properties and fracture behavior). This work reveals that the FE elastic–plastic simulations without the damage and fracture model generally employed in the literature for SBSCSO failure predictions cannot predict the post-ultimate-load damage behavior, fracture initiation by elements removal and sudden drops in load required for determining the SBSCSO displacement at fracture. Consequently, the FE simulation without the damage and fracture model cannot accurately predict the complete SBSCSO tensile properties and fracture behavior. In particular, the FE simulation without the damage and fracture model cannot predict the SBSCSO displacement at fracture required for the seismic and fracture-resistant designs needed for the prevention of the failure of single-bolt shear connections that exhibit the shear-out fracture under extreme loading. FE simulation with the elastic, plastic damage and fracture models represents the appropriate simulation technique for the complete SBSCSO tensile properties and fracture behavior predictions.
ASSESSMENT OF CARBON DIOXIDE EXTRACTION IN A SOLID WASTE MANAGEMENT FACILITY, AKURE, NIGERIA
(2016-09) ELEMILE, O. O.
Carbon dioxide (CO2) emissions from solid wastes is a major contributor to the acceleration of global warming. In Nigeria, CO2 capture has been limited to the energy sector only. There is need to explore the reduction of CO2 emissions from solid wastes through appropriate technologies. This study, therefore was designed to assess CO2 extraction by adsorbents in a Municipal Solid Waste (MSW) management facility in Akure, Nigeria. An exploratory study design with an intervention component was adopted. For a year, wastes brought to the MSW facility from three locations viz: markets, residences and roadside, were characterised and quantified monthly. Chemical characteristics of the wastes were determined using standard methods. Carbon-dioxide emissions were estimated from the MSW composition using the Intergovernmental Panel on Climate Change tools. Air CO2 levels were monitored during the dry and wet seasons using a P-Sense Plus CO2 meter AZ-7755(PSPCM) and seasonal variations computed. A CO2 extractor which uses adsorbents consisting of Sawdust + Potassium Hydroxide (SKH), Sawdust + Sodium Hydroxide (SSH) and Sawdust + Calcium Hydroxide (SCH), all at ratio1:1, was designed and fabricated. The adsorbents were integrated into the equipment to capture CO2 from 5 kg samples of solid wastes burnt under controlled conditions with five replicates for each adsorbents during each test. The potential CO2 in the solid wastes was determined by ultimate analysis, while the concentration of CO2 adsorbed was obtained by finding the difference between the concentration of the CO2 at the inlet and outlet chambers of the extractor measured with the PSPCM. The effectiveness of the extractor combined with the adsorbents was determined by comparing the adsorbed CO2 with the potential CO2. Data were analysed using descriptive statistics and ANOVA at The mean monthly wastes generation from the three locations were 1,004,130.8+742,394.6 kg (biodegradable wastes), 1,322,831.0+810,634.9 kg (plastics) and 1,330,813.5+400,412.4 kg (paper). The mean values for the chemical constituents of these wastes for the three locations, residential, roadside and market respectively were Nitrogen 2.7+0.6, 2.1+0.8 and 3.4+0.7%; Phosphorus 0.10+0.03, 0.10+0.03 and 0.10+0.04% and Carbon 53.2+1.4, 53.1+1.8 and 53.1+1.5%, with no significant difference within the groups. The estimated CO2 emissions was 1.2 Gg/Yr. The ambient CO2 levels ranged between 438.0+7.2 and 630.0+124.5 ppm in the dry season, and 407.3+11.3 and 506.9+71.1 ppm for the wet season. The mean potential CO2 in the solid wastes was 160.0+ 42.0 ppm. The mean CO2 adsorbed were 99.0+24.0 ppm, 45.0+24.1 ppm and 30.0+13.0 ppm for SKH, SSH and SCH respectively. The effectiveness of SKH in the capture of CO2 was 61.9 % as against 20.8 % and 18.8 % by SSH and SCH, respectively. The selected adsorbents were effective in capturing carbon dioxide. Incorporation of Sawdust + Potassium Hydroxide improves the effectiveness of carbon dioxide extraction in the solid waste management facility.
Assessment of Fine Aggregates from Different Sources in Ibadan and Environs for Concrete Production
(2018) AGBEDE O.A.; AJAGBE W.O.
Assessment of natural sand being used as fine aggregate for concrete production in Ibadan and its environs was carried out. Ten sources (F1 – F10) were selected for the study; four (F5, F6, F7, F8) were river sand sources while six (F1, F2, F3, F4, F9, F10) were burrow pit sand sources. Samples from each source were subjected to sieve analysis, atterberg limit, bulk density, specific gravity, water absorption, sand equivalent, clay lumps and friable particles, amount of materials passing 75μm and organic impurities adopting ASTM standard procedures. Results revealed that sand from river sources met all the criteria for concrete production stated in ASTM standard while sand from burrow pits deviated from limits of the standard in some respects. F10 had water absorption of 2.6% which exceeded maximum 2% specified, F9 was not free from clay lumps and friable particles with a significant value of 6% as against 3% maximum specification. F1, F2, F3, F4, F9 and F10 have more amounts of materials passing the 75μm sieve ranging from 10.8% for F9 to 20.1% for F10 than maximum of 5% in standard specification while F1, F9 and F10 showed an indication of having organic impurities. It is recommended that performance test be conducted on concrete made from burrow pits sand before use for concrete production. The knowledge of this study can be used as a prospecting tool for selecting suitable sand for the production of quality concrete.
Assessment of sidewalk system in the University of Ibadan
(University of Ibadan, 2023) Akintayo, F. O.; Agbaohwo, M. O.
Good pedestrian facilities support the ease, comfort and safety of pedestrians. A good pedestrian sidewalk requires a good surface condition with appropriate footpath width and surface quality. This study assessed pavement condition of sidewalks in the University of Ibadan using the Pavement Condition Index (PCI) method. PCI evaluates the surface condition of sidewalks based on distresses observed. The PCI ratings vary from 0 to 100, representing the worst and best surface conditions, respectively. Based on the regular use of sidewalks for access, eighteen major roads were selected within the University of Ibadan. A distress assessment survey was conducted on the roads to collect data on defective sidewalk pavements and their distress conditions. The sidewalks were mainly of two types: plain concrete and concrete slab. Average sidewalk width for fourteen of the roads was less than 1.5 m stipulated in highway design manuals. Sixty percent of the sidewalks were in good condition with PCI values greater than 70. The recurring defects on the plain concrete sidewalk included linear, edge and map cracking. Depression of slab units was the most severe defect on the concrete slap sidewalk. The PCI analysis was used to assess the surface conditions of sidewalks in the University of Ibadan. The results can be used to design maintenance activities to keep the sidewalk system in optimal operational function. Having and updating inventory of the sidewalk system will promote regular routine maintenance and encourage safe use of the system
Assessment of sidewalk system in the University of Ibadan
(Department of Civil Engineering, University of Ibadan, Nigeria, 2023) Akintayo, F. O.; Agbaohwo, M. O.
Good pedestrian facilities support the ease, comfort and safety of pedestrians. A good pedestrian sidewalk requires a good surface condition with appropriate footpath width and surface quality. This study assessed pavement condition of sidewalks in the University of Ibadan using the Pavement Condition Index (PCI) method. PCI evaluates the surface condition of sidewalks based on distresses observed. The PCI ratings vary from 0 to 100, representing the worst and best surface conditions, respectively. Based on the regular use of sidewalks for access, eighteen major roads were selected within the University of Ibadan. A distress assessment survey was conducted on the roads to collect data on defective sidewalk pavements and their distress conditions. The sidewalks were mainly of two types: plain concrete and concrete slab. Average sidewalk width for fourteen of the roads was less than 1.5 m stipulated in highway design manuals. Sixty percent of the sidewalks were in good condition with PCI values greater than 70. The recurring defects on the plain concrete sidewalk included linear, edge and map cracking. Depression of slab units was the most severe defect on the concrete slap sidewalk. The PCI analysis was used to assess the surface conditions of sidewalks in the University of Ibadan. The results can be used to design maintenance activities to keep the sidewalk system in optimal operational function. Having and updating inventory of the sidewalk system will promote regular routine maintenance and encourage safe use of the system
Assessment of the Impact of Road Dualisation on Adjacent Structures: A Case Study of Iwo-Road – Agodi Gate – Bashorun Road in the Ibadan Metropolis
(2019) Ajagbe W.O; Oladejo O.J; Omiwole D.D
Assessment of the impacts of building construction activities on the environment
(Department of civil engineering, University of Ibadan, Ibadan, Oyo-state, Nigeria ,department of chemistry, University of Zululand, zululand, kwazulu-Natal, South- Africa. Department of earth sciences, Olabisi Onabaanjo University, Ago-Iwoye, Ogun State, Nigeria. department of applied chemistry, University of Johannesburg, Johannesburg, South Africa. department of civil engineering, Osun State University, Osogbo, Osun state, Nigeria., 2024-04) Akintayo, F. O.; Oyebade, O. N.; Songca, S. P.; Adebisi, N. O.; Oluwafemi, O.S.; Fadipe, O. O.
Activities in building construction industry contribute to air pollution. In this study, gas data from four locations at each three building construction sites in Doha, Qatar were collected and analyzed. Questionnaires were also administered to companies that are involved in building construction projects. The results showed traces of SO2, CO2, CO and NO2 but in amounts below the detrimental limit stipulated by the Ministry of Environment, Qatar. Questionnaire responses revealed that the extraction of raw materials and the energy consumed during construction occur quite often, but strongly implicated dust generated from construction sites and waste disposal, as major factors causing air pollution in the area. It is therefore, recommended that regular monitoring of air should be carried out within building construction sites to aid detection of air contamination. This will serve as a control measure to stimulate catalytic conversion of exhaust, reuse and recycling of waste materials.
Assessment of Vehicular Emission in Major Roadways within Ibadan Metropolis
(Department of Civil Engineering, University of Ibadan, Ibadan, Nigeria., 2024-06) Akintayo, F. O.; Ikporukpo, D. J.
The aggravation of road traffic as a result of rapid urbanisation and ineffective air quality management systems in urban centres pose a threat to public health. Air pollutants have significant adverse effect on the ecosystem. The study investigated the magnitude of air pollutants and relationship with vehicle emissions in three selected roads noted for their characteristic high traffic volume in Ibadan Metropolis. The concentration of carbon monoxide (CO), carbon dioxide (CO2), nitrogen oxide (NOX) and sulphur dioxide (SO2) in the three selected locations (Beere market road, Mokola interchange, and Oyo road near the University of Ibadan Main Gate) were monitored using a Smart Sensor AS8900 model multi-gas detector and an IOT-based device setup known as the Raspberry pi 3+ B model with gas sensor add-on. The daily monitoring of emission was conducted for 24 days and results analysed using statistical methods. The average recorded pollutant emissions were below the standards set by the WHO. Pollutant emissions 21.81 ± 25.24ppm for carbon monoxide, 411.92 ± 145.11ppm for carbon dioxide, 0.04 ± 0.02ppm for nitrogen oxides and 0.004 ± 0.001ppm for sulphur dioxide. The concentration values of the pollutants varied with the traffic volume. Overall, the analysis indicated that there was no significant relationship between traffic volume and presence of pollutants in the study area. However, the regular agencies ought to further monitor traffic and other related pollutant emissions to ensure environmental safety
Capacity Analysis of Two-lane Highways Operating under Non-ideal Conditions
(Department of Civil Engineering, University of Ibadan, 2015) Akintayo, F. O.; Agbede, O. A.
The highway system is an important component of the transportation system in many countries of the world. Studies have shown that many factors contribute to capacity reduction of highways. Traffic steam characteristics of three highways in Ibadan metropolis were captured in 2011. Models were developed to quantify the prevailing conditions of the roads. The capacity analysis of the roads was carried out based on the methodologies described in the United States Highway Capacity Manual (HCM 2000).The traffic stream was heterogeneous in nature. The analysis showed that the highways were operating under non-ideal conditions which resulted in capacity reduction and performance level. The resulting models are useful in evaluating capacity performance of two-lane highways for Improved optimization of the system
Causes And Prevention Of Erosion In Urban Centres: A Case Of Okeotunu/Sanngo Area Of Ibadan City, Nigeria
(2004) Agbede O.A.; W. O. Ajagbe W.O
The causes of erosion in the study area, Okeitunu/ Sanngo, were investigated via the geology and soil properties of the area, the state of the existing road network and the drainage system, and the solid waste management practice in the local government area. It was revealed that both natural and man made activities contributed to the erosion of the area. Topographical nature of Okeitunu and the inadequate stream channel, in addition to bad environmental sanitation practices, unchecked vegetative removal and lack of enlightenment on the part of the inhabitants on erosion problems are the key factors causing the degradation of the Okeitunu environment. Stabilization of the steep slope, rehabilitation of the existing bare roads and damaged drainage will abate the wearing away of the soil. In addition, the populace needs to be enlightened to know what it takes to initiate or aggravate erosion.
Combined reusing of sorghum husk ash and recycled concrete aggregate for sustainable pervious concrete production
(2022) Tijani, M.A; Ajagbe W.O; Oluwole, A.A
The huge amounts of natural resources and high level of energy consumption in concrete production necessitate the use of agricultural and demolition wastes as alternative construction materials. The present study explores pervious concrete (PC) that includes sorghum husk ash (SHA) and recycled concrete aggregate (RCA) as alternatives to cement and natural aggregate (NA) in standard PC mixtures. PCs were prepared from mixtures derived from replacement levels 0%, 5%, 10%, 15%, 20% and 25% of cement with SHA and 0%, 20%, 40%, 60%, 80% and 100% of NA with RCA. The density, compressive strength and hydraulic properties (void ratio and hydraulic conductivity) of the samples were determined at 28-day using ACI standards. Sustainability efficiency of incorporating SHA and RCA on PC was also investigated using structural efficiency and carbon dioxide (CO2) emission. Their cost effectiveness was equally examined. Results revealed that densities of PC decreased with increase in SHA and RCA amount. Compressive strength and structural efficiency reduced with increase in SHA except at 5% where they were higher than the control. On the other hand, the incorporation of RCA decreased the compressive strength but improved the PC hydraulic properties. CO2 emission and production cost were found reduced with increase in SHA as well as RCA. The maximum reduction of CO2 emission (38.23%) and production cost (51.29%) were obtained when 25% SHA was combined with 100% RCA. The combined usage of SHA and RCA as raw materials in PC was found to be effective in boosting PC’s hydraulic properties at an appropriate compressive strength. The reduction of CO2 discharge and in production cost attributed to the construction materials demonstrates their impacts on mitigating global warming problems and lowering costs of PC production.
Comparative Study on the Design of Elevated Rectangular and Circular Concrete Water Tanks
(2012) AGBEDE O.A.; AJAGBE W.O.
Reinforced concrete overhead water tanks are used to store and supply safe drinking water. Design and cost estimation of overhead water tanks is a time consuming task, which requires a great deal of expertise. This study therefore examines the efficiency of Rectangular and Circular tanks. Tanks of 30m3, 90m3, 140m3 and 170m3 capacities were used in order to draw reasonable inferences on tank’s shape design effectiveness, relative cost implications of tank types and structural capacities. Limit state design criteria were used to generate Microsoft Excel Spreadsheet Design Program, named MESDePro for quick and reliable design. The basic tank’s construction materials- steel reinforcement, concrete and formwork were taken-off from the prepared structural drawings. Results of the material take-offs showed that, for each of the shapes, the amount of each structural materials increase as the tank capacity increases. Also Circular-shaped tank consumed lesser individual material as compared to Rectangular ones. Hence, this will give Circular-shaped tanks a more favoured selection over the rectangular shaped tanks.