Author: Mezie Ethelbert

Reading Time: 2 minutes Fire incidences in buildings are phenomenon that can be avoided but which nevertheless occurs. Reasons for its occurrence include but not limited to: 1. Acts of arson 2. Faulty electrical equipment 3. Human error 4. Poor maintenance of heating equipment 5. Natural events such as lightening To avoid fire incidences, buildings should be designed to minimize the probability of a fire and to protect life and limit property damage if a fire should occur. The steps to achieve this include: 1. Limit potential fire loads, with respect to both combustibility and ability to generate smoke and toxic gases. 2. Provide…

Reading Time: 2 minutes Flood plains are areas that can be overwhelmed by flood. Though not a regular occurrence, when flooding occurs, which chiefly involves rising of a river above its elevation (flood stage), it causes a lot of damage beyond its banks. Generally, it is advisable should not be constructed around flood plains. However, if risk to life of such areas and social and economic considerations justify the construction of buildings at around flood plains, the following points are worthy of note: 1. If there are high areas around the flood plains, preferably cluster the buildings around the high areas. 2. If high…

Reading Time: 4 minutes Earthquakes are one of the sources of lateral loads in buildings. In certain regions of the world that are located in seismic zones such as Indonesia, India, USA, Japan etc., earthquakes are regular occurrence and designs against earthquake forces should be incorporated in buildings. Light buildings such as low-rise buildings not more that 3-storeys above grade or level and wood framed homes are known to have performed well in major seismic events owing to their; Light-weight and resilient construction, The strength provided by nonstructural systems such as interior walls, and Load distribution capabilities These advantages could still present a great…

Reading Time: 3 minutes The following factor usually affect deflection in structural members (especially concrete) Tensile Strength This property is important because the slab will crack when the tensile stress in the extreme fibre is exceeded. In Eurocode, the concrete tensile strength, fctm is a mean value used for deflection calculations and which increases with compressive strength. The effective tensile strength of concrete depends on the degree of restraint to shrinkage movements which in turn depends on wall layout. Creep This is the time-dependent increase in compressive strain in a concrete element under constant compressive stress. Creep is usually considered in the design by…

Reading Time: 3 minutes Tall or high-rise buildings are frequently encountered in society, especially in developed nations. According to Mark Fintel (1974), the socio-economic problems that came with industrialization in the 19th century and the insatiable need for space in the big cities gave the big impetus to high-rise construction. Thus, by the latter part of the 19th century land in the rapidly developing cities was very scarce and the only option was to go up. The development of high-rise buildings faced enormous obstacles associated with their vertical load-bearing capability in the earlier part of the 19th century. With the discovery of reinforced concrete and…

Reading Time: 3 minutes The single most important seeming principle in seismic design is to ensure that the structural components and systems are adequately tied together to perform as a structural unit. However, due to uncertainties surrounding how a sturdy structural system can be achieved, other special considerations are applied in the seismic design to guard against failure.  These considerations include: Over Strength The concept of overstrength is a realization that a shear-resisting system’s ultimate capacity is usually significantly higher than required by a design load as a result of intended safety margins. At the same time, the seismic ground motion (load) is reduced…

Reading Time: 3 minutes Soil-bearing investigations are rarely required for residential construction except in the case of known risks as evidenced by a history of local problems (e.g. organic deposits, landfills, expansive soils, etc.). Soil bearing tests on stronger-than-average soils can, however, justify smaller footings or eliminate footings entirely if the foundation wall provides a sufficient bearing surface. For a conservative relationship between soil type and load-bearing, refer to Table 1. When a soil bearing investigation is desired to determine more accurate and economical footing requirements, the designer commonly turns to ASTM D1586, Standard Penetration Test (SPT), and Split-Barrel Sampling of Soils (ASTM, 1999).…

Reading Time: 3 minutes Title of Test Determination of the workability of concrete or slump of concrete mix Aim of Test To determine the slump/workability of concrete mix Theoretical Background Workability refers to the ease with which concrete can be placed and compacted. The slump test is the most commonly used site method for assessing the workability of a concrete mix. The test entails filling an open-ended conical mould with concrete and measuring the slump or drop in level of the concrete when the mould is lifted up clear. Since the workability of a given concrete increases with the amount of water added, the…