Civil Engineering

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Civil Engineering

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COMPARATIVE ANALYSIS OF TRAFFIC PERFORMANCE OF SMALL AND LARGE CENTRAL ISLAND ROTARIES IN MINNA, NIGERIA
(SAVAP International, 2013) Abubakar, Mahmud; Ndoke, P. N.
Of recent, the government of Niger state has embarked on the construction of roundabouts with small central island rotaries; this paper compares the performance of large central island rotaries with small central island rotaries. The performance of large central island rotaries compares well to the performance of small central island rotaries. Capacities of rotaries with small islands were found to be higher than capacities of large central island rotaries while the delay for large central island rotaries was found to be higher than that of small central island rotaries. However, both large and small central island rotaries were found to be operating at the same level of service. This study provides recommendations to traffic engineers and/or planners on the conditions under which both central island rotaries perform better and, thus, should be considered.
Probability based design of concrete mixes with cow-bone ash admixed cement
(Leonardo Journal of Sciences, 2017) Abubakar, Mahmud; Mohammed Abdullahi; James Isiwu Aguwa
A probability-based procedure for design of concrete mixes with cow-cone ash admixed cement has been developed considering the strength as a random variable. However, the compressive strength of concrete in turn, depends on the properties of its constituent materials: cement, fine aggregate, coarse aggregate and cow-bone ash. The compressive strength data generated experimentally has been analysed using normal-probability distribution functions based on 95% confidence interval. The proposed probability based design was compared to the method of trial mixture. It was observed that for reliability index (β) of 1.3, the proposed probability methodology uses 10.2% less cement content than the method of trial mixture; thus, indicating that the method is conservative. It was also observed that, for concrete grade 25, the proposed methodology gives higher compressive strength at both 7 and 28 days. Hence, the probability-based design procedure was found appropriate and is therefore recommended for the design of concrete mixes with cow-bone ash admixed cement.
Comparative Assessment of Macroscopic Traffic Flow Properties Estimation Methods: A Case for Moving Car Observer Method
(ENGINEERING SCIENCE AND TECHNOLOGY INTERNATIONAL RESEARCH JOURNAL, 2017) Hassan Shuiabu Abdulrahman; A. A. Almusawi; Abubakar, Mahmud
Different methods of estimating macroscopic traffic properties is expected to have varying results even when they are carried out on the same road and during the same time interval. A comparative assessment was carried out between traffic data collected at a point and that collected over a short section; Moving car observer method(MCO). Student’s t-test was used to evaluate both data and it was observed that there was no significant difference between them. The MCO method correlates well with conventional data collection method and it can be used as a substitute for it, assuming conventional data collection method is true
Development of an Android Based Mobile Application for Design and Detailing of Pad Foundations to BS8110
(Epistemics in Science, Engineering and Technology, 2017) Yusuf, A.; Aminulai, H. O.; Abdullahi, A.; Abubakar, Mahmud; Alhaji, B.
Many innovative computer software have been developed to perform the task of designing and detailing structural elements such as beams, columns, slabs and foundations. This design and detailing can be done using mobile devices but software developed to operate on such devices have not been fully developed. However, this research is aimed at developing an android based mobile application for the design of pad foundations to Bs8110. The mobile application developed designs isolated axially loaded-only; axially loaded with moment pad footings as well as combined pad footings. The mobile application developed was tested using three typical test parameters and results compared to the manual computations. There was no significant variation in the steel sections required and provided for the manual design and that generated by the mobile application. The steel required by manual design for the axially loaded pad footing was 835mm2/m and that generated by the application was 837.2mm2/m. That of the axially loaded with moment gave required steel section as 1019mm2/m using manual design. This android based mobile application would thus give the structural engineer the leverage to design pad footings anywhere and anytime.
Development of Sensitivity based Model for Flexural Failure of Singly Reinforced Concrete Slabs Based on BS 8110: 1997
(. Nigeria Journal of Engineering and Applied Sciences (NJEAS), 2017-03-22) Tsado, T.Y.,; Sadiku, S.,; Iorkar, A.; Kolo, D. N.
This research presents mathematical models for checking the effect of variation in key designed parameters on the structural collapse of singly reinforced concrete solid slabs in buildings due to flexural failure based on British Standard (BS) 8110, 1997. The increasing complexity of construction process requires very high level of engineering and management skills to combat the structural collapses widely experienced globally. Most of the collapses were adjudged to be due to improper management arising from variations in structural key design parameters during construction, and this call for mathematical models to check the effect of variation in key design parameters on the structural collapse. The key design parameters considered in this research are; characteristic strength of reinforcement, grade of concrete, diameter and spacing of tension reinforcement, effective depth of tension reinforcement, applied moment. Sensitivity analysis was applied to study the effect of variation in the key parameters on the moment capacity. The results of sensitivity analysis were utilized in regression analysis to develop simplified equations for estimating the moment capacity of the slab. Computer programme was developed based on BS 8110, 1997 standard using Java to verify the model. Flexure safety factor was also checked based on BS 8110, 1997 requirements. Forty five numerical examples were taken to validate the model with the developed computer programme at 5% significance level using Chi-squared as an instrument for sensitivity-based model for flexural failure of singly reinforced concrete slab. The results show that the model is adequate at 5% significance level for checking flexural failure of singly reinforced concrete slab at construction stage based on BS 8110, 1997. It was recommended that the construction practitioners should consider the diverse effect of change in key deigned parameters during construction, otherwise the developed model should be strictly considered for quick safety check especially deflection safety of a solid slab during construction.
Durability Characteristics of Lateritic Subgrade Treated with Iron Ore Tailings and Lime Exposed to Moisture Fluctuations
(. Nigeria Journal of Engineering and Applied Sciences (NJEAS), 2018-02-11) Mohammed, A. M.; Amadi, A. A.; Aguwa, J. I.; Kolo, D. N.
This research evaluated the durability of lateritic subgrade treated with Iron Ore Tailings (IOT) and lime exposed to moisture variations. Representative sample of the subgrade was treated with 0, 5, 10, 15, and 20% IOT and optimal lime percent (6.2%) determined through Eades and Grim pH test. Preliminary tests such as particles size distribution, Atterberg limits and compaction were conducted to characterize the mixtures while Unconfined Compressive Strength (UCS) and CBR-swell tests were carried out to access durability of the soil mixtures. Addition of lime to the soil increased the liquid limit to 45% from 36% obtained in natural soil. Similarly, the plastic limit of the lime-treated sample increased from 16 to 26% with reduced plasticity index. While the natural soil exhibited CBR of 3 and 75% for soaked and unsoaked specimens respectively, the value increased and peaked at 11 and 118% with addition of lime and 15% IOT. Durability of the soil improved with addition of IOT and lime. 15% IOT and lime treated soil recorded the best results with UCS of 240 kN/m2 and 200% Relative Volumetric Stability (RVS), which is a measure of strength loss of a soil. Similarly, swell value of 0% was recorded when the lime-IOT samples were subjected to CBR-Swell test. This shows that the lime-IOT treated samples are less vulnerable to moisture condition normally prevalent in the pavement subgrades.
DEVELOPMENT OF AN ANDROID BASED MOBILE APPLICATION FOR THE DESIGN AND DETAILING OF ISOLATED PAD FOUNDATIONS ACCORDING TO EUROCODE 2
(i-manager’s Journal on Mobile Applications & Technologies, 2019) Yusuf, Abdulazeez; Isiaka, I.; Abubakar, Mahmud; Aminulai, H. O.; Abdullahi, Aliyu; Alayande, T. A.
In a building construction project, it is the responsibility of the structural engineer to come up with a complete design of all structural elements. When this is done manually it is tasking, time consuming, and produces errors with inconsistent results. However, the design can be done using computer software, but this also comes with some downside; it is expensive and complex to use. Thus, this research developed an android based mobile application for the design of pad foundations to Eurocode 2 to put these challenges in check when designing pad footings. The mobile application designs isolated Axially loaded-only and Axially loaded with bending pad footing to Eurocode 2 accurately, with consistent results and in a timely manner. The application was tested using typical test parameters and results are compared to the manual computations. There was no significant difference in the steel sections provided for both methods. All checks that must be satisfactory in design were all checked and found to be satisfactory.
PARTIAL REPLACEMENT OF FINE AGGREGATE WITH WASTE GLASS IN CONCRETE MADE FROM BIDA NATURAL AGGREGATE
(3rd International Engineering Conference (IEC 2019) Federal University of Technology, Minna, Nigeria, 2019) Alhaji, B.; Kolo, D. N.; Abubakar, Mahmud; Yusuf, A.; Abdullahi, A.; Mohammed, S.
This study reports the experimental investigation on the suitability of waste glass as partial replacement for fine aggregate in concrete made using Bida natural aggregates (BNA). Glass is widely used in our daily lives through manufactured products such as sheet glass, bottles, glassware, and vacuum tubing. It is an ideal material for recycling. The increasing awareness of glass recycling speeds up inspections on the use of waste glass with different forms in various fields. Mix ratio of 1:2:4 batched by weight with water – cement ratio of 0.55 was used. The percentage replacement varied from 0% to 40% at 5% intervals. Slump test was conducted to assess the workability of the fresh concrete. The compressive strengths and densities of cured concrete cubes of sizes 150mm x 150mm x 150mm were evaluated at 7, 21 and 28days. A total of 81 concrete cubes were cast and tested. It was observed that an increase in the percentage replacement of fine aggregate with waste glass reduces workability, density and compressive strength. The compressive strength and density vary with days of curing. The findings of this study indicated that the optimum replacement percentage of waste glass with conventional fine aggregate was 20%. However waste glass can effectively be used as fine aggregate replacement (up to 40%) without substantial change in concrete strength.
Effect of Partial Replacement of Fine Aggregate with Sawdust in Light Weight Concrete Production Using Bida Natural Stone as Coarse Aggregate
(Proceedings of the 3rd International Engineering Conference, Federal University of Technology Minna, Nigeria, 2019) Alhaji, B.; Abubakar, M.; Yusuf, A.; Oritola, S. F.; Mohammed, S.; Kolo D. N.
This study investigated the effect of sawdust as partial replacement for Fine Aggregate in light weight concrete production. Sawdust was used to replace Fine Aggregate from 0% to 40% in steps of 5%. 150 x 150 x 150mm concrete cubes were cast for each replacement level, the concrete was cured and the compressive strengths were determined at 7, 21 and 28days curing period respectively. Increase in percentage of sawdust in concrete stant reduction in the compressive strength values with a corresponding reduction in weight. From the result obtained, 5% replacement of Fine Aggregate with sawdust gave a maximum compressive strength 13.11 N/mm2. It was however concluded that the optimum replacement level of 5% can be used as plain concrete for blinding works.
Partial Replacement of Fine Aggregate with waste Glass in Concrete made from Bida Natural Aggregate
(. Proceedings of the 3rd International Engineering Conference, Federal University of Technology Minna, Nigeria, 2019-02-05) Alhaji, B.; Kolo, D. N.; Abubakar M.; Yusuf A.; Abdullahi, A.; Shehu, M.
This study reports the experimental investigation on the suitability of waste glass as partial replacement for fine aggregate in concrete made using Bida natural aggregates (BNA). Glass is widely used in our daily lives through manufactured products such as sheet glass, bottles, glassware, and vacuum tubing. It is an ideal material for recycling. The increasing awareness of glass recycling speeds up inspections on the use of waste glass with different forms in various fields. Mix ratio of 1:2:4 batched by weight with water cement ratio of 0.55 was used. The percentage replacement varied from 0% to 40% at 5% intervals. Slump test was conducted to assess the workability of the fresh concrete. The compressive strengths and densities of cured concrete cubes of sizes 150mm x 150mm x 150mm were evaluated at 7, 21 and 28days. A total of 81 concrete cubes were cast and tested. It was observed that an increase in the percentage replacement of fine aggregate with waste glass reduces workability, density and compressive strength. The compressive strength and density vary with days of curing. The findings of this study indicated that the optimum replacement percentage of waste glass with conventional fine aggregate was 20%. However waste glass can effectively be used as fine aggregate replacement (up to 40%) without substantial change in concrete strength.
Statistical Model for Predicting Slump and Strength of Concrete Containing Date Seeds
(Covenant Journal of Engineering Technology (CJET), 2021) Yusuf, A; Jamal, J. O.; Abubakar, Mahmud; Aminulai, H. O.
Incorporating agro-based waste in concrete can reduce environmental pollution and lead to preserving the ecosystem. In order to reduce trial and error in achieving desired slump and compressive strength of concrete containing Date Seed (DS), this paper examines the slump and compressive strength of concrete using date seeds as a partial replacement for crushed granite. Preliminary tests were conducted on the aggregates to ascertain their suitability for concrete production. Concrete with DS-crushed granite ratios of 0:100, 5:95, 10:90, 15:85, and 20:80 were prepared using a mix ratio of 1:2:4 and a water-cement ratio of 0.5. Slump loss was used to estimate the workability of the fresh concrete. The freshly prepared concrete was cast in 150 x 150 x 150 mm and the compressive strength was determined after curing by full immersion in water for 7, 14, 21 and 28 days. Results showed that the slump of concrete increased with an increase in the content of date seed. The compressive strength was inversely proportional to the date seed content with a DS crushed granite ratio of 20:80 recording the lowest compressive strength (20N/mm2). Linear regression models for slump and compressive strength were developed and found to be sufficient in explaining the experimental data based on a Mean Square Error (MSE) of 0.37 and 0.029 and R2 of 88% and 99% obtained for slump and compressive strength respectively. The study has concluded that DS can be used as a partial replacement for crushed granite in concrete and a linear model is sufficient in predicting the slump and strength of concrete containing date seeds.
Structural Assessment of a Lattice Tower in Federal Capital Territory, Abuja
(Nigeria Journal of Engineering and Applied Sciences (NJEAS), 2022-01-02) Auta, S. M.; Okunyomi, O. O.; Kolo, D. N.
Since the licensing of GSM operators in Nigeria from 2001, there was an astronomical increase in construction and maintenance towers. In a bid to reduce maintenance cost, tower sharing was adopted by some telecommunication providers. The Nigerian Communications Commission guidelines for installation of masts and towers stipulates that all lattice towers should be checked for their structural health status every five years. This requirement has promoted this research work. The objective of the study includes selection of a lattice with weakest parameters, determine the tower’s structural stability and its utilization percentage. A 45m tower with 3-legs erected over 8 years and shared by three telecommunication operators in the Federal Capital Territory (FCT) was selected. Audit was conducted on the tower and its foundation. There were no warped member and no visible crack on the tower foundation. The average compressive strength of the stub columns determined using the digital Schmidt hammer were 25.1, 25.9 and 25.9 N/mm2 for legs A, B and C. From the structural analysis using the EPA model, the tower utilization percentage was found to be at 59.4% after optimization. The STAAD pro. V8i analysis showed that the utilization ratio of the tower members is ≤ 1. Furthermore, design properties for the tower members are less than the properties of the actual tower members used and there was no failed member identified after the structural analysis. In conclusion, the lattice tower can be said to be stable and fit for continuous use.
A Comparative Analysis of Grillage method and Beam line analysis of a reinforced concrete waffle bridge deck
(Nigeria Journal of Engineering and Applied Sciences (NJEAS), 2022-01-12) 8. Adamu, H. N.; Abbass, B. A.; Abubakar, M.; Yusuf, A.; Kolo, D. N.; Shehu, M.
The analysis of reinforced concrete waffle bridge deck using chanchaga bridge as a case study was carried out with the aid of computer program written in MATLAB. The bridge deck which is a beam bridge was idealized to be a waffle slab. A mathematical model of the bridge was developed using the method of grillages because very complex shapes of problem domain with prescribed conditions can be handled easily using the method. The bridge deck was modelled as interconnection of grid elements. The analysis was carried out using direct stiffness matrix method. The nodal displacements and the resulting static internal forces; shear forces, bending moments and twisting moments of each grid element were determined using the matrix. The results obtained using the method of grillages were then compared with beam line analysis and the former method gave a 10% decrease in forces which will result in the reduction of overall design and materials by 10%.
Development of Statistical Models to predict the compressive strength of concrete produced using Quarry dust as partial replacement of fine aggregate
(LAUTECH Journal of Civil and Environmental Studies, 2022-01-12) Kolo, D. N.; Enwongulu, J. O.
Concrete is an assemblage of Cement, aggregates and water. The most frequently used fine aggregate for concrete production is sand sourced from river banks. The continuous use of this river sand as a result of rapid infrastructural development has resulted in its scarcity and often high cost. This paper examines the suitability of using quarry dust (QD) as partial replacement for fine aggregate in concrete production. Preliminary test (specific gravity) was conducted on the aggregates to determine their suitability for concrete production. Concrete with 5, 10, 15, 20 and 25% QD – Fine aggregate content was cast with a mix ratio of 1:2:4. The freshly prepared Quarry Dust Concrete (QDC) was cast in moulds measuring 150 x 150 x 150mm and cured using ponding method. The Compressive strength result shows that replacement of fine aggregate with QD leads to a general increase in compressive strength of concrete. Statistical package for the Social Sciences (SPSS) version 21 was utilised to develop the linear regression models for the 7 and 28 days compressive strength of the QDC. The developed models were found to be sufficient in predicting the 7 and 28 days compressive strengths with R2 values of 98.9% and 95.2 % respectively.
PROBABILITY-BASED CALIBRATION OF LOAD DURATION MODIFICATION FACTORS FOR THE NIGERIAN GROWN TIMBER
(NIGERIA JOURNAL OF ENGINEERING AND APPLIED SCIENCES (NJEAS), 2023) Aguwa. J. I.; Sadiku, S.; Afolayan, J. O.; Abdullahi, A.; Abubakar, Mahmud; Kolo, D. N.
All along, load duration modification factors used in Nigeria for design of timber structures were based on BS 5268 of 2002 and this is not a good engineering practice since the strength of timber depends so much on the soil as well as on the environment. There is the need to localize the modification factors based on our environment since Nigerian grown timber is generally used for all timber structures designed and built in Nigeria. Probability-based calibration of load duration modification factors for the Nigerian grown timber was successfully carried out. The results showed significant difference between the calibrated factors and those from BS 5268 of 2002. The calibrated modification factors are; 1.25 for long-term, 1.35 for medium-term, 1.70 for short term, and 2.0 for very short-term duration. This paper recommends the use of these calibrated load duration factors based on Nigerian grown environment.
Production of Pavement Blocks Using Low Density Polyethylene Product Waste
(SETIC 2022 International Conference: “Sustainable Development and Resilience of the Built Environment in the Era of Pandemic” School of Environmental Technology, Federal University of Technology, Minna 6th – 8th February, 2023., 2023) Aboje, A. A.; Abbas, B. A.; Kolo, D. N.; Abubakar, Mahmud; Abdulsalam, A.
Waste sachet water packs cause considerable land pollution in Nigeria. In this research, pavement block was produced using low density polyethylene products waste (sachet water packs) as an alternative binder. The production was achieved by first converting the sachet water packs into pellets and blending it with sandstone in a mass ratio of 8:2 (A), 7:3 (B) and 6:4 (C) sandstone to pellets respectively. The compressive strength, %water absorption and curing time tests were carried out on the pavement block to determine it suitability and safety for low-traffic use. The compressive strength for polymer concrete samples A, B and C were 13.65N/mm2, 16.99N/mm2 and 20.34N/mm2 respectively. After carrying out the %water absorption test on the polymer concrete A, B and C the following result was obtained: 8.33%, 5.47% and 4.03% respectively. It should be noted that the polymer concrete samples and the control samples which (are cement concrete based) are for light-traffic use (pedestrian, plazas, shopping complexes ramps, car parks, office drive ways, rural roads with low traffic, and residential road).
Numerical Investigation of Reinforced Concrete Beam Containing Iron Ore Tailings as Partial Replacement of Sand
(Conference: 4 th International Conference on Innovations and Challenges in Engineering and Technology for Sustainable DevelopmentAt: Arba Minch University, Ethiopia, 2023) Abubakar, Mahmud; Haruna, M. I.; Abdulrahman, H. S.; Abbas, B. A.
The production of industrial and agricultural residual by-products can generate significant environmental impact. In response, researchers have begun incorporating supplementary materials made from agro-industrial wastes to create more sustainable concrete. However, testing the performance of these waste-based concrete mixtures can be time-consuming and expensive. To address this issue, this study utilized three dimensional non-linear Finite Element simulation using the ABAQUS/CAE software to predict the behavior of a reinforced concrete beam that incorporated 20% IOT as partial sand replacement. The simulation successfully predicted the damage behavior of the 20% IOT concrete, indicating the potential of this modeling approach to accurately predict the performance of waste-based concrete mixtures in various designs.
Reliability Assessment of Natural Aggregate Pulverized Glass Powder Concrete Beam Subjected to Shearing Forces
(Journal of Computational Engineering and Physical Modeling, 2023-01-02) Kolo, D. N.; Kolo, S. S.; Abdulazeez, M. H.
Cement is the most expensive ingredient in the process of making concrete. Reducing the quantity of cement used in the production of concrete with Pulverized glass powder (PGP) will reduce the cost of concrete production and help tackle environmental, disposal and CO2 emission challenges. The results of structural reliability assessment performed on Pulverized glass powder concrete produced using locally sourced Natural aggregate (NA) as coarse aggregate. Concrete cubes measuring 150 × 150 ×150 mm were cast, cured for 28 days and tested using the universal compressive testing machine. First order reliability method (FORM) was employed to determine the level of safety of the reinforced concrete beam. Result of sensitivity analysis under shearing forces shows the beam is structurally safe at a span of 3250 mm with Probability of failure (Pf) of 1.14 × 10-3 , Effective depth of 459 mm and corresponding Probability of failure (Pf) of 5.77 × 10-8 and an Area of Shear reinforcement (Asv) of 201 mm2 with Probability of failure (Pf) of 5.01 × 10-5 .
Probability-Based Calibration of Load Duration Modification Factors for the Nigerian Grown Timber
(2023-01-02) Aguwa, J. I.; Sadiku, S.; Afolayan, J. O.; Aliyu, A.; Abubakar, M.; Kolo, D. N.
All along, load duration modification factors used in Nigeria for design of timber structures were based on BS 5268 of 2002 and this is not a good engineering practice since the strength of timber depends so much on the soil as well as on the environment. There is the need to localize the modification factors based on our environment since Nigerian grown timber is generally used for all timber structures designed and built in Nigeria. Probability-based calibration of load duration modification factors for the Nigerian grown timber was successfully carried out. The results showed significant difference between the calibrated factors and those from BS 5268 of 2002. The calibrated modification factors are; 1.25 for long-term, 1.35 for medium-term, 1.70 for short term, and 2.0 for very short-term duration. This paper recommends the use of these calibrated load duration factors based on Nigerian grown environment.
Reliability Studies on Reinforced Concrete Column Subjected to Axial Load with Natural Stone as Coarse Aggregate
(NAUJournalofCivil Engineering (NAUJCVE), 2024) Kolo, D. N.; Aguwa, J. I.; Abubakar, Mahmud
This paper presents the reliability assessment of a reinforced concrete column subjected to Axial loading. Locally available natural aggregate (NA) was used in concrete production, the results of preliminary tests revealed the aggregate was adequate for concrete production. A typical column cross section of 230 × 240 × 3000mm was adopted and probabilistically assessed. First Order Reliability Method (FORM) was employed to estimate the implied probabilities of failures. The results of the sensitivity analysis showed that the reinforced concrete column is structurally safe at length, breadth and depth of 3200, 240 and 230 mm with Probability of Failures of 1.14 ×10-3, 8.45 × 10-4and 8.45 × 10-4 respectively.