- Shear Capacity of Steel Fiber Non-Metallic (GFRP) Reinforced Concrete
Beams Strengthened in Shear Using CFRP Laminates
Abstract: A total of ten large –scale concrete beams were constructed and tested under four–point monotonic loading until failure .Nine of these beams were longitudinally reinforced with glass fiber reinforced polymer (GFRP) strengthened with externally bonded CFRP laminate while the remain beam was reinforced with conventional steel bars with web reinforcement as control specimen. To examine the shear behavior, the main parameters investigated in this study included volume fraction of fiber (0, 0.50 , 1.0) % reinforcement and wrapped with two different configurations of CFRP laminate (U-Jacket and sheets are side bonded) were examined .The test results were compared with recommended design code .The results are summarized and analyzed in detail in the paper in terms of shear capacity, cracking pattern and shear resisting contribution of FRP and steel fiber . Keywords : Beams ,Shear, Steel fiber , GFRP bars ,Strengthening by CFRP .
Issue No: Vol. 8
- Effect of Flange Width on Flexural Behavior of Reinforced Concrete T-Beam
Authors: Ofonime A. Harry, Ndifreke E. Udoh
Abstract: Reinforced concrete T-section beam is widely used in building and bridge construction. In most cases, the reinforced concrete T-section may be monolithic which implies that part of the slab close to the beam section help in resisting the flexural load. Understanding the effect of flange width of beam in such monolithic section is very crucial in designing effective and efficient structure. This study presents a numerical study of the effect of flange width on the flexural behavior of reinforced concrete T-section beam. Three different flange width which include 200, 400 and 600mm were considered in this study. The result shows that stiffness of the beam increases with increase in flange width. The initial cracking load is influence by the flange width. The wider the flange width, the higher the cracking load. The result in terms of mid-span deflection and cracking shows no appreciable difference in the different flange width considered in this study. Finally, the findings show that behavior of reinforced concrete T-section beam in terms of cracking and failure load, deflection, reinforcement strain and crack pattern can be accurately simulated using LS DYNA. Keywords: Reinforced Concrete T-section beam, Flange width, Cracking load, LS DYNA
Issue No: Vol. 8
- An Assessment of Some Heavy Metal Levels in Drinking Water and Social
Characteristics in Buruli Ulcer Endemic and Non-Endemic Communities in the
Amansie West District
Authors: Anna Amankwah-Minkah, Faustina Gyabaah, George Alexander Dordah
Abstract: Buruli ulcer (BU) is a skin disease caused by Mycobacterium ulcerans (MU). It is often associated with slow-flowing or stagnant water and increase in incidence of the disease is also associated with ecological transformation. Several risk factors have been identified, and a number of transmission mechanisms suggested. However, the exact mechanism of transmission and development of BU through water-related human activities is unknown. A study was carried out to compare concentrations of cadmium, lead and aluminum in drinking water samples and some social characteristics from endemic and non-endemic communities in the Amansie West District in Ghana. Sixty-six drinking water sources were sampled from boreholes and hand-dug wells in the study area. The analysis of the samples showed that the average concentration of cadmium was significantly higher (p < 0.05) in endemic communities than in non-endemic communities even though all the values were below the WHO guideline values of 0.003mg/L. The average concentrations of lead and aluminum were lower in endemic communities than in non-endemic communities, but the differences between the average concentrations were not statistically significant (p > 0.95 for lead, p > 0.30 for aluminum). Aluminum concentrations in all the samples were however lower than the WHO recommended guideline value of 0.1mg/L, whilst the concentration of lead was higher than the recommended guideline value in several communities. It was therefore concluded that cadmium, lead and aluminum may not contribute to the occurrence and transmission of BU. In relation to the social characteristics, the educational level was generally poorer in endemic areas than in the non-endemic areas. The endemic communities used poorer source of water which include streams and hand-dug wells, unlike non-endemic communities which had better sources of water - boreholes and pipe-borne water only. Field observation showed that people in the endemic communities walked barefooted, whilst those in the non-endemic communities had footwear. In this District therefore, attitudinal behaviour/social characteristics may play a role in the occurrence of the disease. Other heavy metals like arsenic should be investigated into, as well as the water usage patterns of the people in the community (to determine whether the disease is water-washed, water-borne or water-based). The organism may be present in the water and/or soil, and it is recommended that more research be carried out to isolate it in the environment. Keywords: Buruli ulcer, Drinking-water, Amansie West, Heavy metals
Issue No: Vol. 8
- Investigation of Blended Oil Palm Nut-Husk Ash and Over-Burnt Bricks
Precast Concrete for Wall Cladding
Authors: T. U. Nwakonobi, F. O. Adoyi, M.O. Isikwue
Abstract: The suitability of Oil palm nut-husk ash (OPNHA) and crushed over-burnt bricks (COBB) was investigated for wall cladding. A mathematical model was developed and used to optimize the mix proportion that produces the maximum strength of OPNHA/COBB concrete for wall cladding, using Scheffe's simplex lattice approach. The model formulated compares favourably with the experimental data. It also satisfies the T and F - statistics. The optimum value of strength predicted by this model is 33.41996N/mm2, at a mix ratio of 1:0:2:4:0.4 of ordinary Portland cement, OPNHA, river sand, COBB and water-cement ratio; followed by 30.84N/mm2 with 0.6:0.4:3:6:0.6 ratios . Three mixtures (optimum, medium and low strength) were selected for other tests viz: impact values, water absorption and thermal properties. The results indicate that mixtures with optimum strength showed greatest resistance to impact load, followed by that with medium and low strength. Water absorption for optimum, medium and low strength were 1.51%, 2.24% and 0.56%, respectively. Thermal conductivity of 0.5017W/mk, 0.339W/mk and 0.394W/mk were recorded for the optimum, medium and low strength mixtures. The thermal resistivity were 1.992mk/W, 2.946mk/W and 2.538mk/W for the optimum, medium and low strength mixtures. Specific heat capacity of 1.134W/kgk, 0.84W/kgk and 0.9115W/kgk and thermal diffusivity of 0.00879m2/s, 0.00989m2/s and 0.00948m2/s were observed for the optimum, medium and low strength mixtures. Thermal absorptivity values were 0.146mm-1, 0.138mm-1 and 0.141mm-1 for the optimum, medium and low strength mixtures, respectively. The values met the set standards (ACI 122R-02 2002, ASHRAE, 2009 and Building and construction Authority, 2010). Keywords: Compressive strength, precast OPNHA concrete, Mix design, Mathematical model, Optimization, Wall cladding.
Issue No: Vol. 8
- Perceptions and attitudes of participants toward urban gardening. A case
study of nutrition gardens in Mucheke town, Masvingo
Authors: Florence Chimbwanda
Abstract: The main objective of the study was to determine participants’ attitude and perceptions towards urban gardening. Characterising the participants and determining the challenges and benefits obtained from urban gardening were also objectives of the study. Data was collect through questionnaire, focus group discussion and observations from the field. The study made use of a sample of 40 participants. Statistical tools such as descriptive statistics were employed and data was analysed through SPSS. The study revealed that urban gardening is an important programme to the community and that it is a better way of generating income. Most of the participants indicated that they can continue gardening without any form of assistance from donors. Benefits from urban gardening include, additional income from sales of vegetables, vegetables for family consumption, and time to socialize. Participants mentioned theft, dilapidating canals, one water point, and limited access to some of the vegetable markets as challenges that they face. The nutrition gardening programme targeted mainly the widowed, orphans, elderly and the sick. The study recommended that the city council should open more areas for urban gardening as this has proved to be a source of food and income so that those that are unemployed and the poor can engage in gardening. This will reduce urban poverty and create employment. Key Words: Urban Agriculture, Perceptions, Attitude, Nutrition gardens.
Issue No: Vol. 8
- Effect of Iron Ore Tailing on Compressive Strength of Manufactured
Laterite Bricks and Its Reliability Estimate
Authors: Yisa; G. L., Akanbi, D. O., Agbonkhese, O.
Abstract: In recent years there is a significant demand of building materials in Nigeria. It is therefore imperative to use mining and mineral wastes in the production of bricks, paving blocks and other value added products since some of these waste materials possess potential characteristics, which can be tapped for various uses. Varying grams of IOT were mixed with constant measured portion of laterite sample and cast into lateritic brick cubes, which were later subjected to compressive strength test at 7 days interval for 21 days. The result of the compressive strength test revealed that the lateritic mix containing varying grams of IOT had higher strength value of 27 N/mm2 when compared with laterite having compressive strength of 14 N/mm2 both for 7 days curing. Reliability of estimates of the compressive strength values from laboratory results for specimens was developed by incorporating data obtained from compressive strength to produce a predictive model. Data obtained were incorporated into a FORTRAN-based first-order reliability program to obtain reliability index values. Variable factors such as water quantity, hydraulic modulus, iron ore tailing, water cement ratio produced acceptable safety index value of 1.0 at the energy levels of all curing period i.e. 7 days, 14 days and 21 days respectively and they were achieved at COV ranges of 10-100 %. The use of iron ore tailing which is a waste material will serve as an alternative source of building material when used as an admixture or replacement of fine aggregate ratio and also possible reduction in quantity of cement. It will also help reduce environmental problems associated with iron ore tailing disposal problems. Keywords: Building Bricks, Compressive Strength, Reliability Analysis, Reliability Index, Iron Ore Tailing, Pozzolana, Utilization
Issue No: Vol. 8
- The Perception of Chinese Construction Professionals Towards the Obstacles
Implementing Green Construction
Authors: Mohammed Shareef M. S. Hasan
Abstract: Green construction plays a key role as building block of sustainable development. The economy is significantly affected by the construction industry of the country. There are certain stakeholders in the green construction industry, however project managers (PMs) play significant role in the process of a construction/ rehabilitation project. Generally, the initiative for change or implementing a new system is very challenging issue to deal with. Project manager has to encounter certain obstacles either at several stages of the green construction projects. The present study deals with the identification of the most critical obstacles that have the greatest influence on a project’s outcome in general and particularly in China. To rank the different obstacles extracted from the literature, we use multi criteria decision making (MCDM) tool i.e. TOPSIS. For obtaining input data a team of six experts (project managers) from top Chinese construction companies with an experience of more than 12 years were selected. The results depicts that the most relevant and important obstacles which are critical for green project management are managerial and psychological obstacles and they need to be addressed to improve the project management performance. Keywords: green construction, project management, topsis, project managers.
Issue No: Vol. 8
- Lack of Maintenance Culture in Nigeria: The Bane of National Development
Authors: TIJANI Saheed Abiodun, ADEYEMI Akinwale Olayemi, OMOTEHINSHE Olusegun Joseph
Abstract: Lackadaisical attitude of Nigerians on maintenance culture has negatively affected infrastructural development which is critical and essential to a Nation’s development. Achieving vision 2020 goals would be attainable if existing structures and facilities are constantly maintained. Poor maintenance culture has drawn the nation a thousand steps backward and one of the stride actions that could salvage the country from the total mess of infrastructural decay is maintenance. This paper aimed at examining lack of maintenance culture through review of archival materials and participative observations. Poor leadership, corruption, attitudinal problem and lack of maintenance policy were identified as major causes of the menace. In conclusion, the paper recommends the inclusion of maintenance culture in national educational curriculum, maintenance policy formulation and appointment of facility managers among others as necessary steps towards making the country among the comity of developed nations. Keywords: Culture, Infrastructure, Maintenance, Maintenance Policy and National Development
Issue No: Vol. 8
- Some Geotechnical Properties of Selected Sub-Base Materials for Road
Authors: Ayodele A.L., Falade F.A.
Abstract: This article presents a laboratory investigation on selected soil samples in relation to their use as road construction material. Soil samples were collected from three different locations and their index, compaction properties (Optimum Moisture Content, OMC and Maximum Dry Density, MDD) were determined. Derived parameters such as activity ratio, grading modulus, plasticity product, plasticity modulus and shrinkage modulus were also determined. The California Bearing Ratio (CBR), Unconfined Compressive Strength (UCS) and the undrained shear strength (Su) of each soil sample were determined. Models relating each of MDD and Su to the OMC were developed. The results showed that the rating of the samples as sub-base material is fair to poor based on CBR values that range from 5 to 12% and Su values that range from 29 to 51 kN/m2. The derived parameters also showed that the soil samples are poor construction materials with one having marginal properties. The models developed showed good correlation between both MDD and Su and OMC based on a correlation coefficient (R2) of 0.934 and 1.000, respectively. Keywords: California Bearing Ratio, Correlation, Derived Parameters, Lateritic Soil, Road Construction,
Issue No: Vol. 8
- Experimental Study on Shear Behavior of Reinforced Self-Compacted Concrete
Authors: Ali Hameed Aziz, Hassan Falah Hassan, Faisal Muayad Abdul Razzaq
Abstract: There are few researches about tapered reinforced concrete elements and it shear failure mechanisms is not well understood. In the present paper, tests were carried out on six beams, simply supported under the effect of two points loading at the ends. Five beam specimens where tapered (non-prismatic shape) while, the last one has a rectangular prismatic shape. The dimensions of the tapered beams were kept constant for all tested beams. The adopted variables were the shape of the tested beams, amount of shear reinforcement and strengthening by CFRP strips. Test results show that the tapered beams without web reinforcement have a superior shear capacity for about (12%) as compared with the prismatic beam, and the strengthening by CFRP strips for tapered beams, enhance the shear capacity for about (30%). Also, the increase of load capacity for tapered beam with half-minimum, and minimum web reinforcement, according to ACI-318 Code for prismatic beam, were (20%) and (33%) respectively as compared with tapered beam without web reinforcement. Keywords: Shear, Reinforced Concrete, Self-Compacted Concrete, Tapered Beams, ACI-318.
Issue No: Vol. 8
- Determination of Trace Metals Quality of Sources of Drinking Water in Some
Selected Communities in the Akuapem South District of the Eastern Region,
Authors: Saviour V.K. Adjibolosoo, P. K. Ofori-Danson, J.A. Ampofo, Dapaah Siakwan
Abstract: The study was undertaken in three communities namely Adamrobe, Aburi and Pokrom-Nsaba, all located in the Akuapim South District of the Eastern Region. These communities depend on streams, wells, and springs for their drinking water requirements. The objective of the study was to assess the trace metals quality of the drinking water sources used by the communities. Water samples from these sources (streams, wells, and springs) were analyzed over a period of twelve months for various water quality parameters including the following trace metals: lead (Pb), cadmium (Cd), zinc (Zn), & arsenic (As), following standard methods designed in APHA, AWWA, and WEF. The results of the study revealed that, most of the mean levels of trace metals registered from the water samples were below the World Health Organization (WHO) and Ghana Water Company Limited (GWCL) recommended critical limits for drinking water standards. The low level of trace metals recorded in the water samples was due to the absence of industrial and mining activities in these communities and their environs. The high level of lead registered in ABSP was as a result of the low pH discovered in the water sample for that station. It is therefore recommended that further study be conducted to track the long term health effects of the trace metals in the drinking water sources used by the study communities. Keywords: Trace Metals Quality, Sources of Drinking Water, Selected Communities, Akuapem South District, Eastern Region, Ghana.
Issue No: Vol. 8