Reading Time: 2 minutes All construction works experience different forms of excavation. The purpose for excavation which always involve removal of soil or earth could be to get to a firm soil for foundation works, drilling operations for water demand, collection of soil samples for laboratory tests, removal of top soil or removal of bad soil. The depth of removal of earth and the pattern of removal distinguishes the different types of excavations. Hence, we have four different types of excavations. The types of excavations include: a. Oversite excavation – this involves the removal of top soil (see Figure 1). b. Reduce level excavation…
Author: Mezie Ethelbert
Mezie Ethelbert
An inquisitive engineer with considerable skills in analysis, design and research in the field of civil engineering.
Reading Time: 6 minutes Introduction: The content of specifications (Nigeria General Specifications for Roads and Bridges – Volume II (revised 1997)) and the discretion of the Engineer or Engineers Representative (ER) guides road construction projects. However, the decision of the Engineer holds the upper hand in conflicting situations. The reason could be related to a peculiarity in site conditions which may not be fully captured by what is laid down in the specifications. Hence, the Engineer needs adequate training and knowledge in order to make the right and informed decisions at every stage of the project. While the decision of the well-trained Engineer holds…
Reading Time: 7 minutes Bamboo is a perennial tree grown in sub-Saharan Africa and have capacity to self-multiply. Recently, some articles were going around showing where bamboo was used as reinforcement bar for buildings. Contractors who are familiar with the use of steel rods are quite skeptical about how this can work out but in actual sense, it is practical. There are many research articles about green buildings and use of bamboo specifically. It may interest you to note that as far back as 1966, the civil engineering laboratory of US Navy developed guide for the design and construction of bamboo reinforced concrete. No…
Reading Time: 3 minutes Waste stabilization pond is one of the three methods of biological treatment of water. Others are the activated sludge process and trickling filter process. Waste stabilization pond is a biological treatment method that depends on bacteria. It has an advantage over other methods because it requires no chemical addition. In this method, three ponds are used in the process (see Figure 1): Facultative pond Anaerobic pond, and Aerobic pond The treatment process usually goes through the three ponds. The anaerobic pond usually operates under anaerobic conditions (without oxygen and light), which is why it is usually deeper. The anaerobic conditions…
Reading Time: < 1 minute A. Liquid limit tests. B. Plasticity tests. C. Grading tests. D. Density/moisture content compaction tests. E. Laboratory CBR tests – for this test, the specimen shall be cured with a wax cover for six (6) days and soaked for twenty-four (24) hours before testing and after allowing the specimen to drain for 10 – 20 minutes. F. Unconfined Compression Strength (UCS) tests. N.B. – a. The cement to be used must comply with British Standard (BS) 12 or with the latest British Standard specification for the cement specified or Nigeria Industrial Standard (NIS) 11 of 1974 or NIS 15 of…
Reading Time: 9 minutes Most man-made structures bear on soil. A soil has a finite strength and not all soil can withstand all kinds of loads/pressure. Therefore, before any structure is sited on any soil, there should be proper investigation of the soil to ensure that the design to be made for the structure should be safe, economical design (through selection of appropriate foundation type) and to reduce as much as possible difficulties in construction due to the nature of the soil. Soil investigation is one of the most important aspect of construction works especially in areas with bad soil. Through soil investigation, the…
Reading Time: 16 minutes The commonest type of slab used in building construction is the solid slab. It is also the one that easy step in structural design. On special occasions, there are other types of slab used in buildings for one or more of the following reasons: 1. Circulation 2. Size of live load 3. Control of deflection 4. Aesthetics 5. Function 6. Client’s appeal, etc Among these slabs, we have: FLAT SLABS The new European unified code for the design of reinforced concrete element, Eurocode 2 (EC 2) defines flat slab as a slab supported by columns, that is beamless reinforced concrete…
Reading Time: 11 minutes The planning stage of setting-out process requires the assemblage of materials and instrument required for the process. The following equipment/instrument are required for setting-out. a. Steel tapes: these are more suitable type of setting out instrument because they are not subject to the same degree of stretching as the fibrous or nylon tape. However, the accuracy of the setting-out depends on the condition of the tape and expertise of the user. b. Levels: automatic levels are usually more commonly used because they produce better reliable results. c. Theodolites: these are used in surveying to determine vertical and horizontal angles by…