WORLD'S LONGEST BRIDGE

The world's longest bridge is the Danyang–Kunshan Grand Bridge in China, part of the Beijing-Shanghai High-Speed Railway. The bridge, which opened in June 2011, spans 102.4 miles (165 kilometers). Another part of that train line, the 70.8-mile (114-km) long Langfang–Qingxian viaduct, is the second longest bridge in the world.

China constructed the Danyang–Kunshan Grand Bridge in just 4 years, employing 10,000 workers, at a cost of about $8.5 million. It crosses low rice paddies, part of the Yangtze River Delta, with just a few miles of the bridge actually crossing the open water of Yangcheng Lake in Suzhou. The bridge averages about 100 feet (31 meters) off the ground.

The world's longest road bridge is the 34-mile (55-km) long Bang Na expressway in Thailand, a six-lane elevated highway that crosses only a bit of water, the Bang Pakong River. Constructing the massive bridge required more than 1,800,000 cubic meters of concrete.

The world's longest continuous bridge over water is the Lake Pontchartrain Causeway in southern Louisiana. The causeway is actually two parallel bridges, with the longer of the two measuring 23.83 miles (38 km). The bridges are supported by 9,500 concrete pilings.

Louisiana's famous bridge faced a challenger in 2011, when China claimed that its Jiaozhou Bay Bridge was the longest spanning water. Guinness World Records decided to split the title into two parts, stating that the 26.4-mile (42.5-km) long Jiaozhou Bay Bridge is the longest bridge over water in aggregate, while the Pontchartrain is the longest continuous bridge. In Jiaozhou, land bridges and sea tunnels make up parts of the overall structure.

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GEOGRAPHIC INFORMATION SYSTEM (G.I.S)

A geographic information system (GIS) is a computer system designed to capture, store, manipulate, analyze, manage, and present all types of spatial or geographical data. The acronym GIS is sometimes used for geographical information science or geospatial information studies to refer to the academic discipline or career of working with geographic information systems and is a large domain within the broader academic discipline of Geoinformatics.What goes beyond a GIS is a spatial data infrastructure, a concept that has no such restrictive boundaries.
In a general sense, the term describes any information system that integrates, stores, edits, analyzes, shares, and displays geographic information. GIS applications are tools that allow users to create interactive queries (user-created searches), analyze spatial information, edit data in maps, and present the results of all these operations.Geographic information science is the science underlying geographic concepts, applications, and systems.
GIS is a broad term that can refer to a number of different technologies, processes, and methods. It is attached to many operations and has many applications related to engineering, planning, management, transport/logistics, insurance, telecommunications, and business.For that reason, GIS and location intelligence applications can be the foundation for many location-enabled services that rely on analysis and visualization.
GIS can relate unrelated information by using location as the key index variable. Locations or extents in the Earth space–time may be recorded as dates/times of occurrence, and x, y, and z coordinates representing, longitude, latitude, and elevation, respectively. All Earth-based spatial–temporal location and extent references should, ideally, be relatable to one another and ultimately to a "real" physical location or extent. This key characteristic of GIS has begun to open new avenues of scientific inquiry.

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NOTES ON PREFABRICATION

Prefabrication is the practice of assembling components of a structure in a factory or other manufacturing site, and transporting complete assemblies or sub-assemblies to the construction site where the structure is to be located. The term is used to distinguish this process from the more conventional construction practice of transporting the basic materials to the construction site where all assembly is carried out.
The term prefabrication also applies to the manufacturing of things other than structures at a fixed site. It is frequently used when fabrication of a section of a machine or any movable structure is shifted from the main manufacturing site to another location, and the section is supplied assembled and ready to fit. It is not generally used to refer to electrical or electronic components of a machine, or mechanical parts such as pumps, gearboxes and compressors which are usually supplied as separate items, but to sections of the body of the machine which in the past were fabricated with the whole machine. Prefabricated parts of the body of the machine may be called 'sub-assemblies' to distinguish them from the other components.
The most widely used form of prefabrication in building and civil engineering is the use of prefabricated concrete and prefabricated steel sections in structures where a particular part or form is repeated many times. It can be difficult to construct the formwork required to mould concrete components on site, and delivering wet concrete to the site before it starts to set requires precise time management. Pouring concrete sections in a factory brings the advantages of being able to re-use moulds and the concrete can be mixed on the spot without having to be transported to and pumped wet on a congested construction site. Pre Fabricated steel sections reduces on-site cutting and welding costs as well as the associated hazards.

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HOW TO CALCULATE THE MATERIALS REQUIRED FOR A KNOWN VOLUME OF CONCRETE

Material estimation includes sand, cement, coarse aggregate and steel for a particular mix design. Let us consider a mix design of 1:2:4 for our estimation practice. The dry volume of total materials required is considered as 1.54 times the wet volume of concrete. This is due to the voids that are present in sand and aggregates in dry stage. Therefore, for our calculation, we will consider the total volume of materials required as 1.54m³ for 1m³ of wet concrete.

a) Bags of cement required:

Volume of cement required for 1m³ of Concrete = (1 x 1.54) / (1 + 2 + 4) = 0.22m³

But the volume of one bag of cement = 0.0347m³;

Therefore, the number of bags of cement = 0.22 / 0.0347 = 6.34 bags of cement; Say, 7 bags.

b) Volume of Sand required:

Volume of sand required = (2 x 1.54) / (1 + 2 + 4) = 0.44m³ of sand.

c) Volume of Coarse Aggregate Required

Volume of Coarse Aggregate = (4 x 1.54) / (1 + 2 + 4) = 0.88m³.

d) Estimation of Reinforced Steel:

Quantity of steel required depends on components of structure, i.e. slabs, beams, columns, foundations, roads etc. To estimate the steel required, there are two methods:

The first method is, when we have the drawings available, we can calculate the total weight of steel required, and dividing it by the total volume of concrete for the different components.

This will give us the weight of reinforcement steel per cubic meter of concrete for the different components.

The second method is assuming the percentage of reinforcement for different components.

The following are the percentages of reinforcement steels generally required for the different components. Its values can vary from structure to structure, and can be assumed from past experiences of similar structure.

For slabs = 1.0% of concrete volume.

For Beam = 2% concrete volume.

For column = 2.5% of concrete volume.

For Reinforced concrete roads = 0.6% concrete volume.

CAUSES OF BUILDING COLLAPSE

Collapse of buildings is not new to Nigeria, neither is it only peculiar to Nigeria. Nevertheless, that will not stop us from taking critical look at the situation and finding a solution to it.

Collapse though can happen to any kind of building, but the casualties that usually follow the collapse of multi-storey buildings can be so terrible.

The collapse of storied buildings in Nigeria usually goes along with it, casualties which can be more up to 20.

But what really motivates multi-storey buildings?

Multistorey buildings are either built because of social status. There are places you get to, and all you would see are very high-rise buildings; so you wouldn’t want your building to be unnoticeable amongst them.

Commercial viability of a location can also make more people to build storied structures in the area because more people would clamour for space in the area.

Some locations are routes to a lot of places; so, high vehicular and human traffic is usually associated with such places, hence more commercial activities, and thus, the need for high-rise buildings.

There is always a tendency of man habiting very close to water because of the opportunity of controlling the waterways which can give opportunity for inter trade between nations. Their closeness to water naturally gave room for shipping ports in these areas, shipping port in turn promotes commercial activities, and commercial activities naturally generates heavy human traffic, and human being requires shelter for himself, his goods and services. So, buildings spring up in these places, and this brings about competition for the very few available spaces. Hence to meet with the demand, designers and building contractors will have to settle for multi-storey buildings because of the increasing unending economic value of these places.

Now, the soils in these areas are sandy and loose soil. They are not strong or compacted soils. Hence, the need for building construction professionals is usually high here. For most of these buildings, they dig long and strong piles foundation. However some few of these buildings still collapse.

 So, what causes the collapse of these buildings?

(1) The first problem is boycotting the professionals -

This issue had been over flogged both in print media and electronic media but it still persists. There is also a problem of egghead professionals that believe they know everything and are not ready to take advice from a colleague. There are known cases like that, which has turned awry.

(2) Contractors cutting corners -

Contractors trying to make gains at the expense of the lives of the users of the building are another problem that has to be tackled. There should be a check from policy makers to make sure specification is thoroughly adhered to by contractors.

(3) Human activities on building -

As insignificant as the human weight may seem to be; the moving up and down of the live loads and the dead load contributes over time in no small measure in wearing down the building. It will take long time though, but houses also expire, and in the case of the types of buildings we have in Nigeria, their lifespan is shorter than those in the civilized world.

(4) Inadequate foundation -

This is the most important part of a building. Unfortunately, a lot of people are not giving adequate attention to this and it is causing more problems. A registered Structural Engineer is very important to you if you are planning on building a strong and solid multi-storey building.

(5) Ageing Building -

Many do not know that buildings also have their life span. Most of the buildings in Lagos Mainland have spent 25 years and above; despite that, they are of shallow foundation and very low quality materials are used for them. As you lay your bed, so you shall lie on it. If you use low quality materials in building, and thereby thinking that you will cut cost, then also be expecting to park out of that building very soon.

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ADVANTAGES OF ENGINE MOULDED BLOCKS OVER HAND MOULDED BLOCKS

Many people mould blocks onsite, using masons and labour to do the job, and claims it is cheaper but I don’t think so when you consider the advantages the engine moulded blocks has over hand-moulded.

(1) Engine moulded blocks compacts better than hand moulded blocks because of the greater pressure that is being applied by the engine. The sands are better compacted and give better products than the hand-moulded blocks.

(2) The engine-moulded blocks are faster to produce; therefore a deal of time is saved which helps in reducing the general project construction time.

(3) The engine-moulded blocks are also finished with a smoother surface which helps the bricklayer during laying and gives the building a nice look.

(4) The engine moulded blocks process helps to reduce theft. Imagine you having a limited time to monitor the forming of the blocks with engine, what would have taken one month to do will be done in three days or less depending on the capacity of the engine. You can take less time to monitor the materials used like cement, quantities of sand bought, and you can monitor the mix ratio/quality unlike the hand-moulded that will delay and create room for the labourers to steal the materials.

(5) Is easier to monitor the forming process as well

(6) The engine-moulded blocks with same mixture ratio as the hand-moulded blocks would be stronger due to better compacting.

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WAYS OF FINANCING YOUR BUILDING PROJECTS. NO. 1. PERSONAL SAVINGS

In order to get a loan to build a house, you must understand that collateral is always needed, but not everybody is comfortable with this arrangement. What becomes of you if you are unable to pay back?

Now, let us talk about all the means available for you through which you can finance your building project, and then, you can choose the one that is most suitable for you.

PERSONAL SAVINGS

This is by far the most popular method people are using to get their house built. There is no fear of creditors knocking on your door and it gives a lot of rest of mind. Honestly, no matter how small your salary is, you can build a house if you set your mind towards it. There is always a case of you saving from whatever your income is. Study has showed that 30% of the moderate level of what we get monthly goes to buying very unimportant goods and junks. So you can cut unnecessary costly foods in costly restaurants.

Sit down, make an inventory of wasteful spending, and start saving 20% only of your income, no matter how small. In 2 years time, you would start building a house of your own. Whatever you were able to save would be enough to start your house.

Personal savings amongst others is the first option if you want to acquire a land and building a house.

ADVANTAGES

i. There are no debts to pay no matter the turn of things.

ii. You have rest of mind, since there are no creditors coming to knock on your door.

iii. It is healthy at the long run. When your mind is free of fear, you are most likely to live a healthier life and avoid hypertension.

iv. It gives you room to channel your earnings towards something valuable and gives you more responsibility.

DISADVANTAGES

i. It may take a long time to achieve your dream

ii. It bites on your income and may moderate your style of living

iii. Staying for too long might make somebody to loose interest altogether and abandon the project.

iv. There is always fear of families of (Omo Onile) Landowners rising up to lay dubious claim on your land especially when the seller is dead, because of long time of building.

v. There is always probability that the savings might be converted for other uses.

vi. Inflation on cost of materials and labour may also be seriously catching in.

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WAYS OF FINANCING YOUR BUILDING PROJECTS. NO. 2. WORKPLACE MORTGAGE AND LOANS

In order to get a loan to build a house, you must understand that collateral is always needed, but not everybody is comfortable with this arrangement. What becomes of you if you are unable to pay back?

Now, let us talk about all the means available for you through which you can finance your building project, and then, you can choose the one that is most suitable for you.

WORKPLACE MORTGAGE AND LOANS

This is most attractive to workers that are planning to invest in Real Estate. Though it is mostly used for personal buildings, but in giving you a honest advice, it would be better for you as a young man or woman to build the house, then rent out and let the building pay back for the loan back as you collect the rents. Then you can use the dividends to finance another project.

The National Housing Fund remains the most attractive leeway for those who desire to build with loans, especially the civil servants. It is designed by the government to aid the Federal Mortgage Bank of Nigeria, with less bureaucracy unlike before, and it offers presently a maximum of N5m at an interest rate of 6%, and a whopping 25 years of repayment tenor. This fund can be joined through any of the mortgage banks in Nigeria.

ADVANTAGES

i. Fast completion of building

ii. The paying back period is long and it is deducted automatically from your monthly income without you feeling the pinch because it is usually very small.

iii. The interest rate is very low.

iv. If you understand real estate business, this opportunity can turn you into a millionaire.

DISADVANTAGES

i. You are indebted for a very long time.

ii. Interest rates, no matter how small, will still eat into your pocket.

iii. Sudden severance of your job may leave you in the cold against your creditors. What if you were unable to get another job?

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WAYS OF FINANCING YOUR BUILDING PROJECTS. NO. 3. THRIFTS AND COOPERATIVES’ HOUSING SCHEMES

In order to get a loan to build a house, you must understand that collateral is always needed, but not everybody is comfortable with this arrangement. What becomes of you if you are unable to pay back?

Now, let us talk about all the means available for you through which you can finance your building project, and then, you can choose the one that is most suitable for you.

THRIFTS AND COOPERATIVES’ HOUSING SCHEMES

This method is becoming more popular among the young workforce and a lot of cooperative housing schemes are springing out daily. It employs the same old mode of operation, only that in this case, you are expected to own a home at the end of it.

All members pool resources together to build houses for each member in areas of choice. This is an alternative to mortgage for the low income earners, who makes monthly minimal contribution overtime.

ADVANTAGES

i. Just as in mortgage loans, fast completion because of readily available funds.

ii. At times members purchase large expanse of land and divide between members which is more comparatively cheap. They get professionals to do the projects in large volume, and the professionals in turn charge less because of large numbers of jobs. Housing cost can be reduced by 25% with this method.

iii. Encourages other mutual benefits and promote friendliness.

DISADVANTAGES

i. It definitely goes without saying that the cooperative society of choice must be well researched and thoroughly investigated to ascertain the commitment and integrity of its members. Some members can decide to default and this may lead to the collapse of the cooperative club.

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THE IMPORTANCE OF GERMAN-FLOOR OR OVERSITE CONCRETE IN A BUILDING

Question: I’m trying to put up a two-flat Bungalow in Lagos. It is already at the foundation stage. I was advised to run German floor after foundation, but considering quotations I’ve got so far, it seems a bit expensive. Another person advised that I should rather spend such money to set blocks and do flooring later. My inquiry into other projects within the site revealed that not everybody did German floor after their foundation. Please, what is the importance of German floor?

-               - Victor.

Answer: Thank you Victor.

The importance of german floor or oversite concrete in a building can’t be overemphasized. There had been a lot of arguments on whether to use a german floor for building projects or not. I have also built too without a german floor in exceptional cases, but this is not the best practice.

On a very solid soil, most people tend to forgo german floor because of the cost of concrete, especially on a one-floor bungalow. However, you must not build in a waterlogged place or area susceptible to heavy settlement without doing german floor.

In other words, german floor is important and very necessary, if you can afford it, even on solid and non-problematic areas.

These are the importance:

(1) German floor stops water from percolating from the soil into the building. It reduces the movement of water from getting to the walls and floor, which may cause damp and result in algae growth around your walls. If the german floor is used with a membrane or nylon or cellophane spread to cover the floor before casting it will reduce water getting up greatly.

(2) The german floor is also a part of foundation; it should be seen as one of the structural elements that make your house to stand. Loads transmitted from the building are also received by the german floor before being transmitted to the foundation. In a raft foundation, it is inevitable to have german floor because you have to blend it with the strips coming from the foundation base, in order to form a mass of concrete that is monolithic and helps to stabilize the building.

(3) For stability. As was mentioned earlier, it is a part of the foundation, and it forms a stable base for both live loads and dead loads in the building. You should be confident while stepping on the floor by making sure you have a solid floor which can also sustain earth tremors or vibrations from machines in and around the building.

(4) When there is a movement in the soil, the german floor helps to redistribute the forces on the building, and spread same around the floor easily which may also help to sustain the building from collapsing.

(5) When there is cracking on the block wall, (for non major cracks) the german floor can serve as a breaking point that will stop blocks from extending crack lines into the other parts of the building; that is, if the crack is up, then it may not extend beyond the german floor towards the foundation, and if the minor crack is from blocks under the german floor, it may not extend beyond it except there is a major defect in foundation due to settlements or improper foundation.

(6) A well done german floor also helps in determining and correcting problems associated with levels when construction is on.

Before your builder cast the german concrete, you have to ask him to take the level of the building round to achieve an even plane which will make your house to come out better during construction.

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