Civil Engineering
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Item Traffic flow rate on Kigali roads: a case of national roads (RN1 and RN3)(Department of Civil Engineering, University of Ibadan, Ibadan, Nigeria, 0201-06) Nyirajana, J.; Akintayo, F. O.; |Coker, A. O.Traffic flow study plays a key important in various functionalities of cities all over the world. The study of traffic flow is also viewed as an essential facility of the country when it wants to establish traffic operations patterns in the progress of road planning. Blockages are accountable for a sequence of harmful effects such as loss of time, scheduling difficulties, carbon dioxide production, and risks of accidents as well as external expense. Besides, inadequate transportation facilities and increased traffic volume hamper urban development, especially in developing nations. The objective of the study was to assess the traffic flow state in two selected national roads of Kigali city. The traffic data were collected from 5 am to 8 pm on two National Roads (RN1 and RN3). The relationship between density and flow rate was analyzed using the fundamental diagram of traffic flow. It was found that the peak hours were from 6 am to 8 am and 5 pm to 8 pm. The highest number of vehicles counted were motorcycles due to shortcuts taken to reduce travel time. The results on RN3 revealed a proportion increase of traffic flow and density in the free-flow regime from 0 to maximum flow of 3346.6 veh/h correspondent to a critical density of 229.9 veh/km. However, in the congested zone regime, there was a decrease in traffic flow and an increase in density. It was found that the curve of flow versus density tended to increase on-road RN1. This study proposed the promotion of public transport and e-commerce as strategies to mitigate the congestion. Also, further research may be carried out on all roads of Kigali city, to provide the level of congestion useful for traffic deviation accordingly.Item 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.Item Suitability of Nigeria Portland-limestone cement grades for building's concrete structural members in various exposure classes(Civil Engineering Department, University of Ibadan, Ibadan, Nigeria, 2015-07) Adewole, K. K.; Ajagbe, W. O.; Akintayo F.O.This work investigates the suitability of the Nigerian Portland-limestone cement grades 32.5 and 42.5 for the construction of building structural members in various exposure condition/classes. The investigation was conducted by comparing the 25MPa, 27MPa and 30MPa average cube compressive strengths and the 30MPa, 30Mpa and 31MPa average cube compressive strengths of 1:2:4, 1:1.5:3 and 1:1:2 concretes produced with Portland-limestone cement grades 32.5 and 42.5 respectively with the minimum durability concrete strength requirements for building structural members in Eurocode 2 exposure classes that are obtainable in Nigeria. Investigation revealed that Portland-limestone cement grades 32.5 is only suitable for the construction of superstructure members inside low humidity buildings (class XC1) and is not suitable for the construction of buried building foundations and external building superstructure members. Portland-limestone cement grade 42.5 is only suitable for the construction of superstructure members in exposure classes XC1 and XC2 (building superstructure members subject to long-term water contact) and building foundations buried in non-aggressive natural soils and groundwater. Both cement grades 32.5 and 42.5 are not suitable for the construction of building external superstructure members sheltered from/exposed to rain and subject to high humidity (class XC3) and/or cyclic wet and dry condition (class XC4). Both cement grades are also not suitable for the construction of building foundations buried in aggressive natural soils and groundwater (exposure classes XA1, XA2 and XA3) and building superstructure members in industrial and coastal areas with airborne, waterborne and/or seawater-borne chlorides (exposure classes XD1, XD2, XD3 and XS1).Item Design of a pre-timed traffic signal at the University of Ibadan main gate intersection(Department of Civil Engineering, University of Ibadan, Ibadan, Nigeria, 2015-12) Akintayo, F. O.; Oluwatobi, O. L .The Traffic control at the University of Ibadan Main Gate intersection is presently controlled by traffic wardens. A pre-timed traffic control signal designed to upgrade the present control measure at the intersection is presented in this paper. Traffic survey was conducted in October 2014 to determine design parameters such as vehicular and Pedestrian volumes at peak hours, and the design was carried out following standard procedures outlined in the Manual on Uniform Traffic Control Devices (MUTCD) and Highway Capacity Manual. The result showed that Peak hour was between 7:00 and 8:00 a.m. with corresponding vehicle volume of 1604 and 550 for the North and South approaches of the intersection respectively. Approximately 24 pedestrians per second cross the intersection during the afternoon peak period. The total cycle length, actual green times for phases 1 and 2 were evaluated as 110, 68 and 34 seconds respectively. The minimum green time required by pedestrians to cross the North Approach was 33 seconds. The designed pre-timed signal is expected to improve the flow of vehicles and pedestrians at the intersectionItem 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 systemItem Life-Cycle assessment of municipal Solid waste in selected landfills in Ibadan(Department of Civil Engineering University of Ibadan, Nigeria, 2015-01) Akintayo, F. O.; Folorunso, C. S.Increased municipal solid waste generation due to rapid urbanization of Africa cities is contributing to global warming. Life-cycle assessment of municipal solid waste was carried out in two selected landfills in Ibadan, Nigeria. The environmental impact index of Global Warming Potential (GWPIOO) for two waste management scenarios: landfill and incineration were evaluated using GaBi6 package. Biodegradable components of the MS W constitute approximately 47%. The GWP for landfilling and incineration are 24.33 and 15.20 kg (C02-equivalent) respectively. In order to reduce global warming impact, incineration waste management technique is preferred to landfilling in the area of study. The methane gas emitted from landfilling could be tapped as alternative energy source for small and medium enterprises in the locality.Item Vehicle headway distribution modelling of free-flowing traffic on two-lane single carriageways(Department of Civil Engineering University of Ilorin, Ilorin, Nigeria, 2015) Akintayo, F. O.; Agbede, O. A.Studies on vehicle headways are employed to understand traffic flow on highways. We model the vehicle headway distributions on a two-lane single carriageway in Ibadan, Nigeria. The Headway Generation Algorithm (THEGA) was developed to generate theoretical values for headway distribution modelling. Headway data for model calibration and validation were collected along Ibadan-Abeokuta Road for five days in April 2008 using a video camera. The generated headways fitted hyperbolic distribution models, and a spreadsheet of cumulative headway distribution was developed for a user-specified volume for flows ranging from 700 to 1000 vehicles per hour (vph). The results associated long headways with low flows, which reduced to short headways as flows increased and random arrival of vehicles changed to a car-following system. The validation of results with the Kolmogorov–Smirnov goodness-of-fit test at 0.01 significance level indicated good fits for the range of observed traffic volumes. The algorithm developed can be used to simulate traffic flows on two-lane single carriageways with the overall goal of efficient and effective traffic management of highway systemsItem Methane generation potential of municipal solid waste in Ibadan(University of Nigeria, Nsukka, 2014-01) Akintayo, F. O.; Olonisakin, O. A.Energy potential from Municipal Solid Waste (MSW) of two landfills serving four local government areas in Ibadan metropolis was estimated in this study. The characterization of the MSW showed that approximately 74% is made up of organic materials with food wastes constituting the highest portion (35%). The energy content of the waste is evaluated as 13,022KJ/kg. The methane potential of the MSW between 2012 and2020 is estimated to be 27,517 tonnes using the Intergovernmental Panel on Climate Change (IPCC) methodology. The gas when collected can be used as alternative energy source for small and medium enterprises in the locality.Item Geotechnical properties of natural composite rock in Ibadan, Nigeria(Akamai University, 2012) Adebisi, N. O; Akintayo, F. O.The physical property of a rock is a pointer to its suitability for civil engineering works. In this study the suitability of composite rock as construction materials is established. Thirty-four fresh block samples of quartz-schist masses were obtained from three locations in Ibadan, Nigeria. Thin sections were prepared from two representative samples, while others were subjected to standard geotechnical laboratory testing. Regression plots were made to assess the degree of association between pairs of dependent physical parameters of the rock. The results show in thin section that individual quartz crystals of the samples have complexly sutured outlines and mutual interlocking. Modal analysis reveals quartz as the dominant mineral with subordinate amounts of muscovite. The density (y) is the least variable parameter and ranges between 2600 and 2660 kg/m3. Water absorption ranges between 0.64 and 3.39 %, indicating good rock materials for construction. Regression analysis shows that approximately 20% of the variation in density and 2% of the void ratio were associated with porosity and water absorption capacity of the rock respectively. These are due to different proportions of quartz and muscovite with voids in the quartz-schist.Item Heuristic approach to course scheduling in a resource-constrained environment(University of Nairobi, 2009-06) Akintayo, F. O.; Oluleye, A. E.This paper describes a simple heuristic for course scheduling in a resource-constrained environment.