Geoelectrical-Geotechnical Studies for Near Surface Characterization, Case History: Lagos, SW Nigeria

Incessant building collapse and foundation failures in Nigeria have continued unabated in recent years, causing loss of lives and properties worth hundreds of thousands of US dollars. This research in Gioni estate Lakowe, Lekki-Epe, Lagos, Nigeria is concerned with an integrated characterization of near-subsurface geomaterials using geoelectrical resistivity tomography and geotechnical techniques as part of the preliminary investigations for foundations studies and other building construction projects. Four traverses of the geoelectrical resistivity measurements using Wenner array configuration were conducted, and cone penetrating data were equally obtained along the same traverse. A borehole data point was equally acquired for ground thruthing. Based on their geoelectrical properties, three lithologies including loose sand, compacted clayey sand and clay/peat units were delineated with apparent resistivity values ranging 50 – 260 Ωm, 20 – 72.2 Ωm and ≤ 27.5 Ωm respectively. Average Cone penetrometer (CPT) value was about 110 kg/cm2 with an average SPT ‘N’ value of 25, indicating that the soil material is of good geotechnical properties. Laboratory tests conducted on the representative soil specimen at 3.75 m depth revealed moisture content (MC) of 66% which can be attributed to the clay contents. The Liquid Limit (WL), Plastic Limit (WP) and Plasticity Index (PI) tests results gives 84%, 30% and 54% respectively. The choice of deep seated foundation such as pile foundation is considered a better alternative to shallow foundation for proposed buildings in the study area where higher loadings are anticipated to transmit the loads to a stable soil laye

Sustainable Green Environment through Utilization of Waste Soda-Lime Glass for Production of Concrete

Recycling and reuse of waste materials remains a major option for waste reduction, preserving the natural resources from further depletion and reduction in greenhouse gases emission thereby contributing to sustainable green environment. In this study, focus on the reuse of waste soda-lime glass crushed into coarse aggregate sizes as a substitute for natural coarse aggregate in normal concrete was investigated. The variables in this study is coarse aggregate while the cement, sand and water-cement ratio were held constant. The crushed waste glass was varied from 0 – 100% in steps of 25% by weight to replace the coarse aggregate in the concrete mix. Concrete mixes were prepared using a mix proportion of 1:2:4 (cement: sand: granite) at water-cement ratio of 0.5 targeting a design strength of 20 MPa. Slump tests were carried out on fresh concrete mixes and tests were also carried out on total number of 60 concrete cube specimens of size 150 x 150 x 150 mm and 60 concrete cylinder specimens of dimension 100 mm diameter by 200 mm height after 3, 7, 28 and 90 days of curing. Results on the slump tests shows a decrease in the concrete workability as the glass content increases. Test results also indicated that the compressive and split tensile strength of the hardened concrete decreases with increasing waste glass content compared with the control. However, concrete mix made with 25% waste glass content compared significantly well with the control and can be suitably adopted for production of normal concrete

Geoelectrical-Geotechnical Studies for Near Surface Characterization, Case History: Lagos, SW Nigeria

Incessant building collapse and foundation failures in Nigeria have continued unabated in recent years, causing loss of lives and properties worth hundreds of thousands of US dollars. This research in Gioni estate Lakowe, Lekki-Epe, Lagos, Nigeria is concerned with an integrated characterization of near-subsurface geomaterials using geoelectrical resistivity tomography and geotechnical techniques as part of the preliminary investigations for foundations studies and other building construction projects. Four traverses of the geoelectrical resistivity measurements using Wenner array configuration were conducted, and cone penetrating data were equally obtained along the same traverse. A borehole data point was equally acquired for ground thruthing. Based on their geoelectrical properties, three lithologies including loose sand, compacted clayey sand and clay/peat units were delineated with apparent resistivity values ranging 50 – 260 mΩ , 20 – 72.2 mΩ and ≤ 27.5 mΩ respectively. Average Cone penetrometer (CPT) value was about 110 2 kg/cm with an average SPT ‘N’ value of 25, indicating that the soil material is of good geotechnical properties. Laboratory tests conducted on the representative soil specimen at 3.75 m depth revealed moisture content (MC) of 66% which can be attributed to the clay contents. The Liquid Limit (WL), Plastic Limit (WP) and Plasticity Index (PI) tests results gives 84%, 30% and 54% respectively. The choice of deep seated foundation such as pile foundation is considered a better alternative to shallow foundation for proposed buildings in the study area where higher loadings are anticipated to transmit the loads to a stable soil layer

Modelling, Analysis and Design of a Multi-Storey Helipad-Car Park: a Proposal for Canaan Land

The rapid growth of urbanization and the ever increasing population of urban centers in modern age of today, has brought about increase in the use of cars, roads and other transportation facilities. This singular factor has created constrains on traffic management system and parking of cars in most of these areas. That is why new innovations and technology need to be put in place to help address this issue and reduce some of the constrains on traffic management system of urban centers and also help improve their parking system. One of these innovations is the introduction of multi-storey car park. The multi-storey car park is one major innovation put in place to help with traffic management system of urban centers in most developed countries and introducing this kind of innovation into the developing countries such as Nigeria would help the traffic management system of major urban centers, bring less environmental hazards with the attendant social and economic gains for the society. That is why this research aims at the modelling, analysis and design of a multi-storey car park which would improve the traffic management of a functional modern society like that of Canaan land. Autodesk Revit and Robot soft wares are adopted and the results obtained are promising and replicable

Use of Building Information Modelling Tools for Structural Health Monitoring

The study of Information and Communication Technology applications in construction industry have developed greatly for computer programming and management strategies. As a response to the increasing challenges of construction projects, extensive researches have brought about numerous ICT tools such as Building Information Modelling tools, Lean Construction and Lean Design tools, and Integrated Project Delivery management tools to succour the construction industry. Building Information Modelling in particular is acknowledged in the industrial and academic circles as the new Computer Aided Design paradigm and hence, repositions it as the preferred approach to managing design, construction, maintenance and documentation of building projects. But the use of Building Information Modelling tools for structural health monitoring have not been adequately explored. This study employs Building Information Modelling as a tool for diagnosing and correcting structural design flaws in a building under construction. The design flaws in a complex staircase was identified while more realistic options of the design were quickly created and articulated for a safer outcome of the project. The results obtained highlights the benefits of Building Information Modelling applications such as enhanced safety, improved cost, time savings, quality improvements and better project management and execution

GEOELECTRICAL INVESTIGATIONS FOR GROUNDWATER EXPLORATION IN CRYSTALLINE BASEMENT TERRAIN, SW NIGERIA: IMPLICATIONS FOR GROUNDWATER RESOURCES SUSTAINABILITY

This research involves the subsurface geological characterization for groundwater potential assessment within the campus of the Polytechnic of Ibadan, southwestern Nigeria. The study is directed towards groundwater resources exploration, development and management in the campus. Five 2D resistivity imaging traverses were conducted using Wenner array in addition to five VES surveys using Schlumberger array that provide layering information and geoelectrical parameters. Three geologic layers delineated from the 2D resistivity inversion models include predominantly clayey sand/ sandy clay top soil (overburden), partly weathered or fractured basement and fresh basement. Their inverse model resistivity values ranges 6.68 – 98.6 m , 68.0 – 929 2252 m and m with bottom depths ranges 3.8 – 6.4 m and 6.4 – 10 m respectively. 1D model inversion from VES results also delineate three lithologies classifying both topsoil and some part of the partly weathered basement as overburden with resistivity and thickness range 483 – 1746.9 m , 1.1 – 1.8 m; partly weathered or fractured basement 60.3 – 93.5 m , 8.4 -12.9 m and fresh basement 984.6 – 2078.9 m . The saturated portion of the partly weathered or fractured basement at depth will favour groundwater exploration and development in this area, while the relatively shallow overburden thickness would serve as the protective layer and recharge for the fractures

Experimental Investigation of Yield Strengths of Steel Reinforcing Bars Used in Nigerian Concrete Structures

Concrete is the most widely used construction material in the world and is best used in conjunction with reinforcing steel for optimal results. But a lot of behavioral and durability issues affect the performance of this composite material. The level of understanding of these durability issues depends on the sophistication of the environment of application of the material. In the developing nations such as Nigeria, where the incidence of building collapse is very frequent and over 95% of the cases of collapse affect reinforced concrete structures, a lot need to be done to understand effectively the true causes of the building collapses. Among these include the behavior of the reinforcing steel adopted in Nigerian construction industry. This research evaluates the behavior of reinforcing steel used in Nigerian concrete structures. The research considers the test results of 12mm and 16mm reinforcing bars adopted for structural purposes within Lagos State environment which have experienced the most cases of building collapse in Nigeria. A total of 433 samples from sites located in 10 Local Government Areas of Lagos State were analyzed with statistical tools. About 42% of the 12mm bars and 46% of 16mm bars failed to meet the BS code prescription of 460N/mm2 yield strength and about 28 % and 33% of 12mm and 16mm bars, respectively, failed to meet the Nigerian’s professional’s prescription of 410N/mm2

Application of Recycled Waste Materials for Highway Construction: Prospect and Challenges

Industrialization and continuous increase in population growth have contributed immensely to various kinds of solid waste generation which most times are indiscriminately dumped. These activities have negative effects resulting in environmental pollution which could be a menace to the environment. Moreover, to preserve the environment, many researchers have made efforts to ensure that some of these wastes are recycled and utilized in the production of various alternative materials as a means of sustainable technology. Among several alternative materials for construction, some of these wastes are considered to be very useful. This study examines the various recycled waste materials that can be adopted for construction, including their prospects and challenges. Some of the recycled waste materials examined are plastic waste, mill tailings, geopolymers, waste glass, rubber tyre waste, shingles, construction and demolition wastes (C&D) and slag. These recycled materials have been accepted globally due to their characteristic properties which made the materials suitable in the construction industry. This review also examines some limitations relating to the adoption of these materials as alternative construction materials for highway/pavement construction. However, it is generally accepted that reuse of waste materials in construction industry has minimal environmental impact and their exploration would have huge economic impact

Implications of Construction Materials on Energy Efficiency of Buildings in Tropical Regions

Construction materials play important roles on energy consumed for conditioning building internal spaces. Thermal properties of construction materials are the least factors considered during material selection process since strength, economy, and aesthetics are more sought after. Also, with the rising rate of global warming, more solar radiation would reach building surfaces, leading to increased energy requirements for cooling, especially in the tropical regions. For future buildings to be sustainable, they must have low energy requirements. This research considers the impacts of common construction materials in Nigeria on the energy required for conducive thermal comfort within building envelopes. Five types of building materials combination models of rammed earth wall with thatched roof, shipping container wall and roof, sand-crate block wall with aluminum roof, brick wall with concrete roof and glass wall with concrete roof were considered. Autodesk Ecotect environmental simulation and analysis software was used for the research. Building models were created for each of the selected materials and subjected to climate data of Ota in Nigeria. From the results obtained, rammed walls with thatch roofs model, similar to traditional systems of the old proved to be the most energy efficient construction material combination for a one storey building in this tropical climate while the shipping container model and glass wall with concrete roof model proved least energy efficient. The resulting temperature curves and the cooling load chart for the considered material models will be a useful tool for designers in search of materials for energy efficiency in the tropical regions

Influence of Calcined Clay on the Strength Characteristics and Microstructure of Recycled Aggregate Concrete for Sustainable Construction

Utilization of concrete wastes as aggregate in conventional concrete is regarded as a promising way of achieving sustainability within the built-up environment. This study investigated the performance of high strength concrete produced using recycled aggregate (RCA) with the addition of calcined clay in the concrete mixes. The recycled aggregate was sourced from concrete rubbles and treated by soaking in water, while calcined clay was sourced from the pilot pozzolana plant of the Nigerian Building and Road Research Institute (NBRRI). The recycled concrete aggregates were used as a replacement for coarse aggregate at levels of 0, 20, 40, 60, 80 and 100%, using a mix ratio of 1:1:2 at a constant water-binder ratio of 0.25. Superplasticizer was added to ensure the workability of the mixes. The calcined clay was added at 15 and 20% partial replacement for cement in the mixes. Physical and chemical properties of the materials used were determined, while the workability of the concrete mixes was examined using the slump. The compressive strength of the hardened concrete was determined after 7, 28 and 56 days of curing using 100 mm cube samples. Scanning Electron Microscope (SEM) was used to evaluate the morphology of selected concrete. Results showed that soaking of the recycled aggregate in water limit the water absorption rate of the RCA aggregates in the mixes, while the addition of calcined clay was observed to slightly reduce the workability of the concrete mixes. A reduction trend in compressive strength was noticed as the percentage of recycled aggregate increases, however, a significant increase in compressive strength was observed with the addition of calcined clay at 15% cement replacement. An optimum concrete mix containing 20% recycled aggregate and 15% calcined clay showed improve performance compare to the other mixes. The implication of these results suggests that recycled concrete aggregate can be used for the production of sustainable structural concrete