Segzy14 Classroom; Learn More On Buildings - Properties - Nairaland
Nairaland Forum / Nairaland / General / Properties / Segzy14 Classroom; Learn More On Buildings (10035 Views)
Building Collapse: Lagos Demands Integrity Test On Buildings / Solar Power Working Within Budget Working With The Boss Segzy14 Of Nairaland / The History Of Stone Decorations On Buildings. (2) (3) (4)
(1) (2) (3) (4) (Reply) (Go Down)
| Segzy14 Classroom; Learn More On Buildings by Nobody: 11:18am On Jan 26, 2015 |
Good morning all, i will be posting some useful informations here. You can ask questions where you don't understand. |
| Re: Segzy14 Classroom; Learn More On Buildings by Dominionng(m): 11:24am On Jan 26, 2015 |
Reporting to class... 1 Like |
| Re: Segzy14 Classroom; Learn More On Buildings by Nobody: 11:30am On Jan 26, 2015 |
QUANTITIES OF MATERIALS PER CUBIC METRE OF CONCRETE Quantity of materials such as cement, sand, coarse aggregates(granite) and water required per cubic meter of concrete and mortar varies with the mix design of the concrete and mortar respectively. Following table gives the estimated quantity of materials required per cubic meter of mortar and concrete for various nominal mixes. 1 Share
|
| Re: Segzy14 Classroom; Learn More On Buildings by Nobody: 12:01pm On Jan 26, 2015 |
continuation of the table 1 Share
|
| Re: Segzy14 Classroom; Learn More On Buildings by Nobody: 12:03pm On Jan 26, 2015 |
still on the table 1 Share
|
| Re: Segzy14 Classroom; Learn More On Buildings by Nobody: 12:05pm On Jan 26, 2015 |
NOTES: 1. F.A.= Fine Aggregates, C.A.= Coarse Aggregates 2. The table is based on assumption that the voids in sand and crushed stone are 40 and 45 percent respectively. 3. Air content of 1 percent has been assumed. 4. For gravel aggregates decrease cement by 5 percent, increase sand by 2 percent and coarse aggregate in proportion to fine aggregate in mix. 4. No allowance has been made in the table for bulking of sand and wastage. |
| Re: Segzy14 Classroom; Learn More On Buildings by Nobody: 12:27pm On Jan 26, 2015 |
[b]CRACKS IN CONCRETE DUE TO MOISTURE CHANGE Building materials such as concrete, mortar, bricks, wood etc are porous in nature and expand by absorbing moisture from atmosphere and shrink on drying. These changes in building materials are cyclic in nature and are caused during moisture changes. But building materials undergo irreversible changes due to change in moisture content during its initial conditions. These initial changes cause shrinkage or expansion of materials. For example, irreversible movement in materials are shrinkage of cement and lime based materials on initial drying i.e. initial shrinkage/plastic shrinkage and expansion of burnt clay bricks and other clay products on removal from kilns i.e. initial expansion. INITIAL SHRINKAGE IN CONCRETE AND MASONRY Initial shrinkage of building materials which is partly irreversible, occurs in all building materials that are cement / lime based such as concrete, mortar, masonry units, masonry and plaster etc. This initial shrinkage is one of the main causes of cracking in building structure. Initial shrinkage as the name suggests occurs only once in the lifetime of concrete and mortar, i.e. during the time of construction when the moisture dries out during setting process. Initial shrinkage is most significant cause for the cracks in structures[/b] |
| Re: Segzy14 Classroom; Learn More On Buildings by Nobody: 12:29pm On Jan 26, 2015 |
[b]The effect of initial shrinkage in concrete and mortar depends on following factors: a) Cement content – Shrinkage of concrete and mortar increases with richness of mix. b) Water content – Increase in water quantity used in the mix increases the shrinkage. c) Maximum size, grading and quality of aggregate –With increase in the maximum size of aggregate with good grading, the water-cement ratio decreases for the same workability requirement of concrete. The use of less water reduces the initial shrinkage of concrete due to reduction in porosity. For example, the shrinkage of cement sand mortar is 2 – 3 times that of cement concrete using 20mm maximum size of aggregate and 3 – 4 times that of cement concrete using 40mm maximum size of aggregate. d) Curing of concrete and masonry – Proper curing from the start of initial setting to at least 7 to 10 days helps in reducing initial shrinkage . The moisture provided through curing helps concrete and masonry to expand and thus, when they dry up, the final shrinkage is less. e) Surface area of aggregates -Surface area of concrete increases with increase in fine aggregates and this requires large water quantity for the required workability. With increase in water quantity, the shrinkage of concrete and masonry increases when they dry up. f) Chemical composition of cement – Shrinkage is less for the cement having greater proportion of tri-calcium silicate and lower proportion of alkalis i.e. rapid hardening cement has greater shrinkage than ordinary port-land cement. g) Temperature of fresh concrete and relative humidity of surroundings – With reduction in the ambient temperature the requirement of water for the same slump/workability is reduced with subsequent reduction in Concreting done in mild winter have much less cracking tendency than the concreting done in hot summer months. In cement concrete 1/3rd of the shrinkage take place in the first 10 days, ½ within one month and remaining ½ within a year time. Therefore, shrinkage cracks in concrete continues to occur and widens up to a year period.[/b] |
| Re: Segzy14 Classroom; Learn More On Buildings by Nobody: 12:33pm On Jan 26, 2015 |
[b]Plastic shrinkage of concrete: Cracks appearing on the surface of concrete before setting of concrete is due to plastic shrinkage of concrete. The cause of shrinkage cracks in concrete is due to settlement of heavy aggregates at the bottom of concrete and rise of water to the surface. This process continues till the concrete has set and it is called as bleeding of concrete. As long as the rate of evaporation is lower than the rate of bleeding, there is a continuous layer of water at the surface known as “water sheen”, and shrinkage does not occur. When the concrete surface looses water faster than the bleeding action bring it to the top, shrinkage of top layer takes place, and since the concrete in plastic state can’t resist any tension, cracks develops on the surface. These cracks are common in slabs. The extent of plastic shrinkage in concrete depends on: Temperature of concrete, Exposure to the heat from sun radiation, Relative humidity of ambient air and velocity of wind.[/b] 1 Share
|
| Re: Segzy14 Classroom; Learn More On Buildings by Nobody: 12:36pm On Jan 26, 2015 |
Plastic settlement cracks Plastic settlement cracks occurs on concrete surface due to settlement of large aggregates. In the case of reinforced concrete, sometimes the settlement of aggregates is obstructed by reinforcement. These obstructions break the back of concrete above them forming the voids under their belly. Plastic settlement cracks are normally observed: Over form work tie bolts, or over reinforcement near the top of section. In narrow column and walls due to obstruction to sedimentation by resulting arching action of concrete due to narrow passage. At change of depth of section. 1 Share
|
| Re: Segzy14 Classroom; Learn More On Buildings by Nobody: 12:37pm On Jan 26, 2015 |
Initial expansion of concrete: When the clay bricks are fired during manufacturing, due to high temperature not only the intermolecular water but also water that forms a part of molecular structure of clay is driven out. After burning, as the temperature of the bricks falls down, the moisture hungry bricks starts absorbing moisture from the environment and undergoes gradual expansion, bulk of this expansion is irreversible. For the practical purpose it is considered that this initial expansion ceases after first three months. Use of such bricks before cessation of initial expansion in brickwork, will cause irreversible expansion and may lead to cracking in masonry |
| Re: Segzy14 Classroom; Learn More On Buildings by Nobody: 1:52pm On Jan 26, 2015 |
[b]PROTECTION OF BUILDINGS AGAINST DAMPNESS One of the requirements of the building is that it should be dry. Dampness in a building may occur due to bad design, faulty construction and use of poor quality of materials. Dampness not only affects the life of the building but also creates unhygienic conditions of the important items of work in the construction of a building. The treatment given to prevent leakage of water from roof is generally termed as water proofing whereas the treatment given to keep the walls, floors and basement dry is termed as damp proofing. DEFECTS OF DAMPNESS IN BUILDINGS: The various defects caused by dampness to building may be summarized as under: It causes efflorescence which may ultimately result in disintegration of bricks, stones, tiles etc. It may result in softening and crumbling of plaster. It may cause bleaching and flaking of paint with the formation of coloured patches. It may result in the warping, buckling and rotting of timber. It may lead to the corrosion of metals. It may cause deterioration to electrical fittings. It promotes growth of termites. It creates unhealthy living conditions for the occupants. CAUSES OF DAMPNESS IN BUILDINGS Absorption of moisture by the building materials is one of the chief causes of dampness. On acoount of granular nature of materials, moisture finds an easy access through the voids and this aided by capillary action assists the moisture to travel in different directions. Thus, either on account of faulty design of structure or bad workmanship or by use of defective structures or by use of defective materials, moisture may find its way on the interior of the building either through the wall, floor or roof. SOURCES OF DAMPNESS IN BUILDINGS The important sources of dampness may be summarized as below: Dampness rising through the foundation walling. Moisture from wet ground may rise well above the ground level on account of capillary action. Splashing rain water which rebounds after hitting the wall surface may also cause dampness. Penetration of rain water through unprotected tops of walls, parapet, compound walls, etc may cause dampness. In case of sloped roofs, rain water may percolate through defective roof covering. In addition faulty eaves course and eave or valley gutters may allow the rain water to descend through the top supporting wall and cause dampness. In case of flat roofs, inadequate roof slopes, improper rain water pipe connections, and defective junction between roof slab and parapet wall may prove to be the source of dampness. METHODS OF DAMP PROOFING Following methods are generally adopted to prevent the defect of dampness in a structure: Membrane damp proofing Integral damp proofing Surface treatment Guniting Cavity wall construction (1) Membrane Damp Proofing: This consists in providing layers of membrane of water repellant material between the source of dampness and the part of the structure adjacent to it. This type of layer is commonly known as dam proof course (or DPC) and it may comprise of materials like bituminous felts, mastic, asphalt, plastic or polythene sheets, cement concrete, etc. Depending upon the source of dampness, DPC may be provided horizontally or vertically in floors, walls, etc. Provision of DPC in basement is normally termed as tanking. General principles to be observed while laying DPC are: The DPC should cover full thickness of walls excluding rendering. The mortar bed upon which the DPC is to be laid should be made level, even and free from projections. Uneven base is likely to cause damage to DPC. When a horizontal DPC is to be continued up a vertical face a cement concrete fillet 75mm in radius should be provided at the junction prior to the treatment. Each DPC should be placed in correct relation to other DPC so as to ensure complete and continuous barrier to the passage of water from floors, walls or roof. (2) Integral Damp Proofing: This consists in adding certain water proofing compounds with the concrete mix to increase its impermeability. Such compounds are available in market in powdered as well as in liquid forms. The compounds made from clay, sand or lime (chalk, fuller’s earth, etc) help to fill the voids in concrete and make it water proof. Another form of compounds like alkaline silicates, aluminium sulphates, calcium chlorides, etc react chemically when mixed with concrete to produce water proof concrete. Pudlo, Imperno, Siks, etc. are some of the many commercially made preparation of water proofing compounds commonly used. The quantity of water proofing compounds to be added to cement depends upon manufacturers’ recommendations. In general, one kg of water proofing compound is added with one bag of cement to render the mortar or concrete water proof. (3) Surface Treatment: As described earlier, the moisture finds its way through the pores of materials used in finishing. In order to check the entry of the moisture into the pores, they must be filled up. Surface treatment consists in filling up the pores of the surfaces subjected to dampness. The use of water repellant metallic soaps such as calcium and aluminium oleates and stearates is such effective in protecting the building against the ravages of heavy rain. Bituminous solution, cement coating, transparent coatings, paints, varnishes fall under this category. In addition to other surface treatment given to walls, the one economically used is lime cement plaster. The walls plastered with cement, lime and sand in proportion of 1:3:6 is found to serve the purpose of preventing dampness in wall due to rain effectively. (4) Guniting: This consists in depositing an impervious layer of rich cement mortar over the surface to be water proofed. The operation is carried out by use of a machine known as cement gun. The assembly broadly consists of a machine having arrangements for mixing materials and a compressor for forcing the mixture under pressure through a 50mm diameter flexible hose pipe. The hose pipe has nozzle at its free end to which water is supplied under pressure through a separate connection. The surface to be treated is first thoroughly cleaned of dirt, dust, grease or loose particles and wetted properly. Cement and sand (or fine aggregates) usually taken in proportion of 1:3 to 1:4 are then fed into the machine. This mixture is finally shot on the prepared surface under a pressure of 2 to 3 kg per square cm by holding the nozzle of the cement gun at the distance of 75 to 90 cm from the working surface. The quantity of water in the mix can be controlled by means of regulating valve provided in the water supply hose attachment. Since the material is applied under pressure, it ensures dense compaction and better adhesion of the rich cement mortar and hence treated surface becomes water proof. (5) Cavity Wall Construction; This consists in shielding the main wall of the building by an outer skin wall leaving a cavity in between the two. The cavity prevents the moisture from traveling from the outer to the inner wall. [/b] 1 Like |
| Re: Segzy14 Classroom; Learn More On Buildings by Nobody: 2:26pm On Jan 26, 2015 |
[b]SETTING OUT A BUILDING PLAN ON GROUND A building is set out in order to clearly define the outline of the excavation and the centre line of the walls, so that construction can be carried out exactly according to the plan. The centre line method of setting out is generally preferred and adopted. PROCEDURE Fig.1 as shown below: Example plan to be set out on the ground 1. From the plan (fig 1), the centre line of the walls are calculated. Then the centre lines of the rooms are set out by setting perpendiculars in the ratio 3:4:5.(Pythagoras thoery) Suppose the corner points are a, b, c, d, e, f and g which are marked by pegs with nails on top. 2. The setting of the corner point is checked according to diagonals ac, bd, cf and eg. 3. During excavation, the centre points a, b, c, d, e, f, g may be removed. Therefore the centre lines are extended and the centre points are marked about 2m away from the outer edge of excavation. Thus the points A1, A2, B1, B2 and like wise, are marked outside the trench. Centre line are shown clearly by stretching thread or rope. The centre points fixed 2m away from the excavation are marked with sit out pegs. 4. From the plan details, the width of excavation to be done is also marked by thread with pegs at appropriate positions. 5. The excavation width is then marked by spade or a digger 6. If the plan is much to complicated and follows a zigzag pattern, then the centre pegs are kept at suitable positions according to site conditions[/b]
|
| Re: Segzy14 Classroom; Learn More On Buildings by Nobody: 8:17pm On Jan 26, 2015 |
more still coming |
| Re: Segzy14 Classroom; Learn More On Buildings by trekkie: 9:54am On Jan 27, 2015 |
carry on your work. please i want to build an event hall with parking for 50 cars/shop/bakery/garden... do you think one plot of land is enough? hall should be able to seat 500. thanks please reply thanks |
| Re: Segzy14 Classroom; Learn More On Buildings by Nobody: 11:04am On Jan 27, 2015 |
trekkie: hmmm,all these on one plot? Are you kidding? |
| Re: Segzy14 Classroom; Learn More On Buildings by Nobody: 6:22pm On Jan 27, 2015 |
. |
| Re: Segzy14 Classroom; Learn More On Buildings by Nobody: 8:28pm On Feb 04, 2015 |
DAMP PROOF COURSE (DPC) Materials for Damp Proof Course (DPC): An effective damp proofing material should have the following properties; It should be impervious. It should be strong and durable, and should be capable of withstanding both dead as well as live loads without damage. It should be dimensionally stable. It should be free from deliquescent salts like sulphates, chlorides and nitrates. The materials commonly used to check dampness can be divided into the following three categories: Flexible Materials: Materials like bitumen felts (which may be hessian based or fibre/glass fibre based), plastic sheeting (polythene sheets) etc. Semi-rigid Materials: Materials like mastic, asphalt, or combination of materials or layers. Rigid Materials: Materials like first class bricks, stones, slate, cement concrete etc. |
| Re: Segzy14 Classroom; Learn More On Buildings by Nobody: 8:42pm On Feb 04, 2015 |
[b]SELECTION OF MATERIALS FOR DAMP PROOF COURSE: The choice of material to function as an effective damp proof course requires a judicious selection. It depends upon the climate and atmospheric conditions, nature of structure and the situation where DPC is to be provided. The points to be kept in view while making selection of DPC materials are briefly discussed below: DPC above ground level: For DPC above ground level with wall thickness generally not exceeding 40cm, any one of the type of materials mentioned above may be used. Cement concrete is however commonly adopted material for DPC at plinth level, 38 to 50mm thick layer of cement concrete (1:2:4 mix) serves the purpose under normal conditions. In case of damp and humid atmosphere, richer mix of concrete should be used. DPC Material for floors, roofs etc: For greater wall thickness or where DPC is to be laid over large areas such as floors, roofs, etc, the choice is limited to flexible materials which provide lesser number of joints like mastic, asphalt, bitumen felts, plastic sheets etc. The felts when used should be properly bonded to the surface with bitumen and laid with joints properly lapped and sealed. DPC Material for situations where differential thermal movements occur: In parapet walls and other such situations, materials like mastic, asphalt, bitumen felts and metal (copper or lead) are recommended. It is important to ensure that the DPC material is flexible so as to avoid any damage or puncture of the material due to differential thermal movement between the material of the roof and the parapet. DPC material for Cavity Walls: In cavity wall construction, like cavity over the door or window should be bridged by flexible material like bitumen felt, strips or lead etc.[/b] |
| Re: Segzy14 Classroom; Learn More On Buildings by Nobody: 9:15pm On Feb 04, 2015 |
[b]BUILDING CRACKS- CAUSES & REMEDIES 1. Permeability of concrete: As deterioration process in concrete begins with penetration of various aggressive agents, low permeability is the key to its durability. Concrete permeability is controlled by factors like water-cement ratio, degree of hydration/curing, air voids due to deficient compaction, micro-cracks due to loading and cyclic exposure to thermal variations. The first three are allied to the concrete strength as well. The permeability of cement paste is a function of water-cement ratio given good quality materials, satisfactory proportioning and good construction practice; the permeability of the concrete is a direct function of the porosity and interconnection of pores of the cement paste. 2. Thermal movement: Thermal movement is one of the most potent causes of cracking in buildings. All materials more or less expand on heating and contract on cooling. The thermal movement in a component depends on a number of factors such as temperature variations, dimensions, coefficient of thermal expansion and some other physical properties of materials. The coefficient of thermal expansion of brickwork in the vertical direction is fifty percent greater than that in the horizontal direction, because there is no restraint to movement in the vertical direction. Thermal variations in the internal walls and intermediate floors are not much and thus do not cause cracking. It is mainly the external walls especially thin walls exposed to direct solar radiation and the roof which are subject to substantial thermal variation that are liable to cracking. Remedial Measures: Thermal joints can be avoided by introducing expansion joints, control joints and slip joints. In structures having rigid frames or shell roofs where provision of movement joints is not structurally feasible, thermal stresses have to be taken into account in the structural design itself to enable the structure to withstand thermal stresses without developing any undesirable cracks. 3. Creep Concrete when subjected to sustained loading exhibits a gradual and slow time dependant deformation known as creep. Creep increases with increase in water and cement content, water cement ratio and temperature. It decreases with increase in humidity of surrounding atmosphere and age of material at the time of loading. Use of admixtures and pozzolonas in concrete increases creep. Amount of creep in steel increases with rise in temperature. 4. Corrosion of Reinforcement A properly designed and constructed concrete is initially water-tight and the reinforcement steel within it is well protected by a physical barrier of concrete cover which has low permeability and high density. Concrete also gives steel within it a chemical protection. Steel will not corrode as long as concrete around it is impervious and does not allow moisture or chlorides to penetrate within the cover area. Steel corrosion will also not occur as long as concrete surrounding it is alkaline in nature having a high pH value. Concrete normally provides excellent protection to reinforcing steel. Notwithstanding this, there are large number of cases in which corrosion of reinforcement has caused damage to concrete structures within a few years from the time of construction. One of the most difficult problems in repairing a reinforced concrete element is to handle corrosion damage. Reinforcement corrosion caused by carbonation is arrested to a great extent through repairs executed in a sound manner. However, the treatment of chloride-induced corrosion is more difficult and more often the problem continues even after extensive repairs have been carried out. It invariably re-occurs in a short period of time. Repairing reinforcement corrosion involves a number of steps, namely, removal of carbonated concrete, cleaning of reinforcement application of protection coat, making good the reduced steel area, applying bond coat and cover replacement. Each step has to be executed with utmost care. When chlorides are present in concrete, it is extremely difficult to protect reinforcing steel from chloride attack particularly in cases where chlorides have entered through materials used in construction and residing in the hardened concrete. This increase in volume causes high radial bursting stresses around reinforcing bars and result in local radial cracks. These splitting cracks results in the formation of longitudinal cracks parallel to the bar. Corrosion causes loss of mass, stiffness and bond and therefore concrete repair becomes inevitable as considerable loss of strength takes place Remedial Measures: Reinforcement steel in concrete structures plays a very important role as concrete alone is not capable of resisting tensile forces to which it is often subjected. It is therefore important that a good physical and chemical bond must exist between reinforcement steel and concrete surrounding it. Due to inadequacy of structural design and /or construction, moisture and chemicals like chlorides penetrate concrete and attack steel. Steel oxidizes and rust is formed. This results in loss of bond between steel and concrete which ultimately weakens the structure. The best control measure against corrosion is the use of concrete with low permeability. Increased concrete cover over the reinforcing bar is effective in delaying the corrosion process and also in resisting the splitting. 5. Moisture Movement: Most of the building materials with pores in their structure in the form of intermolecular space expand on absorbing moisture and shrink on drying. These movements are cyclic in nature and are caused by increase or decrease in inter pore pressure with moisture changes. Initial shrinkage occurs in all building materials that are cement/lime based such as concrete, mortar, masonry and plasters. Generally heavy aggregate concrete shows less shrinkage than light weight aggregate concrete. Controlling shrinkage cracks. Shrinkage cracks in masonry could be minimized by avoiding use of rich cement mortar in masonry and by delaying plaster work till masonry has dried after proper curing and undergone most of its initial shrinkage. In case of structural concrete shrinkage cracks are controlled by using temperature reinforcement. Plaster with coarse well graded sand or stone chip will suffer less from shrinkage cracks and is preferred for plastering for external face of walls. Considering the building as a whole, an effective method of controlling shrinkage cracks is the provision of movement joints. The work done in cold weather will be less liable to shrinkage cracks than that in hot weather since movement due to thermal expansion of materials will be opposite to that of drying shrinkage. 6. Poor Construction practices. The construction industry has in general fallen prey to non-technical persons most of whom have little or no knowledge of correct construction practices. There is a general lack of good construction practices either due to ignorance, carelessness, greed or negligence. Or worse still, a combination of all of these. The building or structure during construction is in its formative period like a child in mother’s womb. It is very important that the child’s mother is well nourished and maintains good health during the pregnancy, so that her child is healthily formed. Similarly for a healthy building it is absolutely necessary for the construction agency and the owner to ensure good quality materials selection and good construction practices. All the way to building completion every step must be properly supervised and controlled without cutting corners. Some of the main causes for poor construction practices and inadequate quality of buildings are given below: Improper selection of materials. Selection of poor quality cheap materials. Inadequate and improper proportioning of mix constituents of concrete, mortar etc. Inadequate control on various steps of concrete production such as batching, mixing, transporting, placing, finishing and curing Inadequate quality control and supervision causing large voids (honey combs) and cracks resulting in leakages and ultimately causing faster deterioration of concrete. Improper construction joints between subsequent concrete pours or between concrete framework and masonry. Addition of excess water in concrete and mortar mixes. Poor quality of plumbing and sanitation materials and practices. 7. Poor structural design and specifications Very often, the building loses its durability on the blue print itself or at the time of preparation of specifications for concrete materials, concrete and various other related parameters. It is of crucial that the designer and specifier must first consider the environmental conditions existing around the building site. It is also equally important to do geotechnical (soil) investigations to determine the type of foundations, the type of concrete materials to be used in concrete and the grade of concrete depending on chemicals present in ground water and subsoil. It is critical for the structural designer and architect to know whether the agency proposed to carry out the construction has the requisite skills and experience to execute their designs. Often complicated designs with dense reinforcement steel in slender sections result in poor quality construction. In addition, inadequate skills and poor experience of the contractor, ultimately causes deterioration of the building. Closely spaced of reinforcement steel bars due to inadequate detailing and slender concrete shapes causes segregation. If concrete is placed carelessly into the formwork mould, concrete hits the reinforcement steel and segregates causing fine materials to stick to the steel, obstructing its placement and is lost from the concrete mix while the coarse material falls below causing large porosity (honeycombs). Slender structural members like canopies (chajjas), fins and parapets often become the first target of aggressive environment because of dense reinforcement, poor detailing, less cover of concrete to the reinforcement steel. Added to all this, low grade of concrete and poor construction practices can make the things worse. It is necessary for the structural consultant to provide adequate reinforcement steel to prevent structural members from developing large cracks when loaded. To sum up, the following precautions are required to be taken by the Architects, Structural Consultants and Specifiers: Proper specification for concrete materials and concrete. Proper specifications to take care of environmental as well as sub – soil conditions. Constructable and adequate structural design. Proper quality and thickness of concrete cover around the reinforcement steel. Planning proper reinforcement layout and detailing the same in slender structures to facilitate proper placing of concrete without segregation. Selection of proper agency to construct their designs. Architects and Engineers are parents of the buildings they plan and design and therefore their contribution to the health and life of the building is quite significant. Once the plans are drawn the structural designs and specifications are prepared, it is then the turn of the agency to construct the building and bring the blue print to reality. Special care must be taken in the design and detailing of structures and the structure should be inspected continuously during all phases of construction to supplement the careful design and detailing. 8. Poor Maintenance A structure needs to be maintained after a lapse of certain period from its construction completion. Some structures may need a very early look into their deterioration problems, while others can sustain themselves very well for many years depending on the quality of design and construction. Regular external painting of the building to some extent helps in protecting the building against moisture and other chemical attacks. Water-proofing and protective coating on reinforcement steel or concrete are all second line of defence and the success of their protection will greatly depend on the quality of concrete. Leakages should be attended to at the earliest possible before corrosion of steel inside concrete starts and spalling of concrete takes place. Spalled concrete will lose its strength and stiffness, besides; it will increase the rate of corrosion as rusted steel bars are now fully exposed to aggressive environment. It is not only essential to repair the deteriorated concrete but it is equally important to prevent the moisture and aggressive chemicals to enter concrete and prevent further deterioration. 9. Movement due to Chemical reactions. The concrete may crack as a result of expansive reactions between aggregate containing active silica and alkalines derived from cement hydrations. The alkali silica reaction results in the formation of swelling gel, which tends to draw water form other portions of concrete. This causes local expansion results in cracks in the structure. To control Cracks due to alkali-silica reactions, low alkali cement, pozzolona and proper aggregates should be used. 10. Indiscriminate addition and alterations. There have been some building collapses in our country due to indiscriminate additions and alterations done by interior decorators at the instance of their clients. Generally, the first target of modifications is the balcony. Due to the requirement to occupy more floor area, balconies are generally enclosed and modified for different usages. Balconies and canopies are generally cantilever RCC slabs. Due to additional loading they deflect and develop cracks. As the steel reinforcement in these slabs have less concrete cover and the balcony and canopy slab is exposed to more aggressive external environment, corrosion of steel reinforcement takes place and repairs become necessary. The loft tanks are generally installed in toilets or kitchens, which are humid areas of the buildings. The structure in addition to being overloaded is also more prone to corrosion of reinforcement steel in these areas and therefore deteriorates and if not repaired, part of the building can even collapse.[/b] |
| Re: Segzy14 Classroom; Learn More On Buildings by Dieumerci(m): 10:46pm On Feb 04, 2015 |
Following! |
| Re: Segzy14 Classroom; Learn More On Buildings by Nobody: 9:37am On Feb 05, 2015 |
Dieumerci: welcome |
| Re: Segzy14 Classroom; Learn More On Buildings by Nobody: 10:30pm On Feb 13, 2015 |
.... |
| Re: Segzy14 Classroom; Learn More On Buildings by mujeebmuhsin: 8:22am On Mar 20, 2015 |
Hello All, I am a silent but ardent follower of the property section. I have learnt a lot concerning building courtesy to segzy and his likes like Haj Muftau, spyder and many of those who share their experiences and knowledge. I say big THANK YOU. Unfortunately, I am not so advantaged to use the services of some of the professionals here because my project is down north (Kano). I started my building with the intention of roofing it with aluminium roof. Therefore, I used few RCC columns. The lintel of the building is already done but now I am toiling with the idea of decking. I wanted the decked top to be used for ACs, dishes, tanks, as a sit out and can also be used for sleeping during very hot nights (by the way, north can get very hot at times). My question: Is it possible add columns that will support the weight of the decking, tanks, and live weight? Thank you. |
| Re: Segzy14 Classroom; Learn More On Buildings by Nobody: 7:00pm On Mar 20, 2015 |
mujeebmuhsin: Can u post pics of your building? |
| Re: Segzy14 Classroom; Learn More On Buildings by mujeebmuhsin: 5:38am On Mar 21, 2015 |
Thank you segzy, These are some of the pictures i could lay my hands on. I am not around to take pictures that can give you more knowledge about the building. To summarize, 1. the german floor isn't done yet. 2. All four corners of the house has columns. There are also four other columns at some corners of the house. 3. The lintel went round the house. |
| Re: Segzy14 Classroom; Learn More On Buildings by Nobody: 9:50am On Mar 23, 2015 |
mujeebmuhsin: i will get back to you |
| Re: Segzy14 Classroom; Learn More On Buildings by skytech2020(m): 9:30pm On Mar 24, 2015 |
Pls sir, explain further how to use the Pythagoras theorem in setting out |
| Re: Segzy14 Classroom; Learn More On Buildings by Dieumerci(m): 8:53am On Mar 25, 2015 |
engrgordon: Hello Sir, @engrgordon, this is another person's thread. Get your own thread, showcase ur works and stop spamming every thread in this section. Thanks. |
| Re: Segzy14 Classroom; Learn More On Buildings by mac04: 8:16pm On Apr 06, 2015 |
segzy14:Hello segzy.I have an issue bothering me.I have water flowing from other site into my site.What can I do stop this.Note that owners of the other sites are yet to start work on theirs while I'm almost done with mine.pls ur expert idea is needed urgently |
| Re: Segzy14 Classroom; Learn More On Buildings by segcymoor(m): 10:27pm On Apr 06, 2015 |
mac04:Drainage control! 1 Like |
Best Modern Pop Celings, Artworks, Cornices, Skirtings @ Affordable Rates / Please, Urgent Help With MDF Gloss For Furniture. / Price Slash! Brand New Digital(tokheim) Petrol Dispensers For Ur Filling Station
(Go Up)
| Sections: politics (1) business autos (1) jobs (1) career education (1) romance computers phones travel sports fashion health religion celebs tv-movies music-radio literature webmasters programming techmarket Links: (1) (2) (3) (4) (5) (6) (7) (8) (9) (10) Nairaland - Copyright © 2005 - 2024 Oluwaseun Osewa. All rights reserved. See How To Advertise. 99 |