Construction Hints

These are materials (usually metals) which have unfilled valence bond and thus provide vacant energy states into which electrons in the valence state can move. The movement of electrons is an electric field is facilitated by gain of velocity and momentum as it moves towards the positive electrode. This is due to added energy which therefore requires an occupied energy State at a higher level. Example of conductors are Cu, All, Fe, etc. Metals with few electrons in their valence make excellent conductors of electricity. Forms of conductor are wires, cables and bus-bars (rods, tube etc)

These are metals in which the valence band are completely filled and electrons are readily available for movement into the conduction band and creating an electron-hole pair in the structure of the material and apparent electrical conditions. Examples of semi conductor materials are group IV elements such as carbon, silicon, germanium, tin. Semi conductor can be classified into two forms : Intrinsic and Extrinsic semi conductor

The Strain developed in a material is directly proportional to the Stress producing it. Thus there is linear relationship between stress and strain which is tenable within certain limits for most materials

Stress: This is the intensity of the internal force, which is the magnitude of the sum of forces within a section, is divided by the cross-section. Stress = F/A. (N/m²) Strain: This is the change in the dimension(s) of a material in a state of stress. It can either be comprehensive or tensile. Tensile stress results in extension  of length while comprehensive stress shortens the length of a material. Strain = L-Lo/ Lo

1. Strength : The ability if a timber to withstand stress or external load.    i.e   -Bending parallel to the grain,   -Compression parallel and     perpendicular to the grain,    -Tensile parallel to the grain    -shear parallel to the grain. 2. Elasticity: modulus of elasticity by Inertial. Elasticity = Elasticity x Inertial

1. Density: This is the ratio of mass per volume of a timber structures. Timber with a close packed grain tends to handle a high density than those with much spaced grain. 2. Seasoning: This is process of reducing moisture content from from timber. 3. Thermal conductivity. 4. Thermal Expansion.

Factors are used in all engineering design to allow for variability in loading, material, workmanship etc..which can not be define with absolute certainty, here, the strength of the material or structural element must always exceed the effects of loadings by margin of its factor of safety. Factor of safety =  material strength/design load or Ultimate stress/actual stress NB:- Safety factor applied at one point in design is called overall safety factor, Applied at several points is called partial safety factors.

In engineering, it is called the safety margin required in order to insure safety during loading or the remaining strength after load is applied. It can also be said to be how much of structures total capacity is held in reserve during loading of structural elements. Margin of safety = (Failure load/Design load ) - 1

Timbers is that part of tree that can be used for structural proposes/construction and carpentry. MECHANICAL properties of timber includes; 1. Strength :- this is the ability of timber to withstand stress or external load. i.e . Bending stress, compression stress, tensile stress, shear stress. 2. Elasticity :- EI Its ratio if Modulus of elasticity to its inertial. PHYSICAL properties of timber includes; 1. Density : this is the ratio its mass and volume. Timber with a close packed grain tends to handle a higher loading than those with much spaced grain. 2. Thermal Expansion. 3. Thermal conductivity 4. Seasoning : this is process of reducing moisture content from timber. This could be natural seasoning or artificial seasoning.

Culvert is an open/close drain structure that allows water to flow below a road. It’s like a tunnel carrying a stream of water flow. A Ring/Pipe Culvert Procedure for construction of a common Ring/Pipe Culvert (road junction culvert) includes; I.       Marking Of Alignment: - The surveyor marked out the alignment for the trench to be dug. II.       Digging/Excavation: The surveyor marked out the dept of the culvert to be excavated with an excavating machine. For a 1m pipe culvert, the mathematical process of obtaining the required dept is to sum together the total width of the pipe + base + blinding. For dept:  A pipe of width 1000 mm, base of 150 mm and blinding of 50 mm (though optional). . Hence 1000mm + 150mm + 50mm = 1200mm (1.2 m) So an excavation of 1200mm (1.2m) is required from the to level of the natural ground (sub grade level) surface. For wid...

  V.        Next step is laying of concrete base on the blinded surface and the positioned reinforcement. A concrete base of 150 mm is to be laid or cast on the blinded floor, concrete grade C20 of ratio 1:2:4 is allowed (See concrete grading and mix ratio). A guiding panel is placed into position to guild in the laying of the concrete base in order to achieve a uniformly alignment base edge, thickness and width, also to manage concrete material while pouring. The base is cast with the U shape reinforcement bottom in between the concrete base achieving concrete cover below and above.   VI.        After setting and drying of the concrete base, next is to position the side wall panel form work. The floor base is marked to give the required one meter (1000 mm) internal width where the panel will be positioned. The panel wall spacing is 100mm, and wall height of 1000mm (1 meter), the pan...

Surface water ( i.e., rain water) that falls on the ground surface such as; open field, paved areas or road surface, roof tops etc are channeled to a main drain naturally or through a constructed channel which is referred to as drainage. Procedure for construction of a common drainage (trench) (1m x 1m U drainage) (reinforced). includes; I.       Marking Of Alignment: The surveyor marked out the alignment for the trench to be dug. II.       Digging/Excavation: The surveyor marked out the dept of the trench to be excavated with a mechanical excavating machine. For a 1m x 1m drainage, the mathematical process of obtaining the required dept is to sum together the dept of the required drain + base + blinding. For dept:  A drain of dept1000 mm, base of 150 mm and blinding of 50 mm. Hence 1000mm + 150mm + 50mm = 1200mm (1.2 m) So an excavation of 1200mm (1.2m) is required...

1.) Nitel Building   Lagos  160 M  ( 520 Ft.), 32 Floors, Completion Date: 1979 2.) Union   Bank   Headquarters   Building ,   Lagos . 124 M (407 Ft), 28 Floors. Completion  Date;??     3.) Cocoa House   Ibadan . 105 M (344 Ft.), 6 Floors, Completion Date; 1965 4.) Independence House Lagos 103 M (388 Ft.), 23 Floors Completion Date; 1960  5.) Intercontinental Hotel Lagos 100 M (330 Ft) 22 Floors  Completion, 2013 6.) Great   Nigeria   House   Lagos . 95 M  (312 Ft.), 22 Floors, Completion  Date ; ?? 7.) National Oil Headquarters Lagos 83 M (272 Ft) 23 Floors,  Completion  Date; 1984 8.) Stock Exchange House Lagos , 83 M (272 Ft) 22 Floors, Completion  Date;?? 9.) Uba House   Lagos , 80 M (260 Ft)   20 Floors,  Completion ...