Browsing by Author "Abdullahi, M.,"

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Analysis of Safety Performance in Nigerian Construction Industry
(Nigeria Journal of Engineering and Applied Sciences (NJEAS), 2018-02-22) Kolo, D. N.,; Tsado, T. Y.,; Abdullahi, M.,; Yakubu, D.M.,; Aguwa, J. I.
The quest for the provision of adequate housing for all has translated to the increase in activities of Building construction industry in Nigeria. This growth is accompanied however with cases of poor safety performancewhich at times leads to structural failure. This study investigates and analyses safety performance in Nigerian construction industry. Investigatory survey research method (work study) was adopted to appraise the aim and objectives of the study through field and questionnaire approach. Questionnaire survey consisting of a five point Likert scale was conducted to solicit information from the respondents, and a total of 120 questionnaires were issued to construction professionals and workers on the sites visited. 92 questionnaires representing 76.67% response rate were retrieved and analysed using Statistical Package for Social Sciences (SPSS) version 21. Communalities test, Principal Component Analysis along with ANOVA were utilised for data analysis. A total of thirty-two (32) factors influencing safety performance were identified from literature, subsequently principal component analysis was utilised to reduce the list to nine (9) significant principal factors. The top nine principal factors influencing safety performance determined from the research are: Relationship between Supervisors and Employees on site, Geographical Location (Environmental Factors: Natural and Working Environment), Working Procedure, Ear defenders not worn (while working under noisy equipment), Talk by Management on Safety, Tidy Site, Safety Communication, Operatives job experience and Ladders used without being tied secured. These factors were further incorporated into a regression model. The adjusted coefficient of determination of the model was 0.98; this shows that the model has the capability of explaining 98% of variability in the data under consideration. This implies that the model is adequate in evaluating safety performance. It is therefore recommended that key industry professionals and stakeholders should channel available resources to the determined nine (9) principal safety performance factors.
Structural Reliability Studies of Reinforced Concrete Beam subjected to Shearing forces with Natural Stone as Coarse Aggregate
(USEP: Journal of Research Information in Civil Engineering, 2019-02-12) Kolo, D. N.,; Aguwa, J. I.,; Tsado, T. Y.,; Abdullahi, M.,; Yakubu, D. M.,; Abubakar, M.
This paper presents experimental and structural reliability studies performed on Bida natural stones (BNS) used as coarse aggregate in concrete production. Construction activities based on these naturally occurring materials are major steps towards industrialisation and economic integration of developing countries like Nigeria. This explains the huge interest over the years in utilising such materials as substitute or partial replacement for concrete constituents. The method adopted to appraise the aim and objectives of the study was laboratory experimentation. A total of 80 concrete cubes of 150 mm × 150mm × 150 mm were cast and used for this study. First order reliability method (FORM) was employed to ascertain the level of safety of the beam. Sensitivity analysis was further conducted by varying the span, effective depth and area of shear reinforcement of the beam in shear. The result revealed that the reinforced concrete beam utilising Bida natural stones is structurally safe at a span of 3000 mm and 3250 mm for unwashed and washed Bida natural stones respectively with probabilities of failure of 1.07 × 10-3 and 1.14 × 10-3. Both unwashed and washed Bida natural stones were structurally safe at effective depth of 439 mm with probabilities of failure of 5.87 × 10-3 and 1.31 × 10-3in shear.