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Construction Work

As most of you all already know, I enjoy informing you about many different aspects of the repair/skill/labor industry. I do this because I think it is only fair that everyone should know what is going on out there. Today I want to talk about construction. Many people do not know much about constructors, except that they build things. Well I can tell you they do more than just build things.

In general, there are three types of construction:

  1. Building construction
  2. Heavy/highway construction
  3. Industrial construction

Each type of construction project requires a unique team to plan, design, construct, and maintain the project.

Building construction

Building construction is the process of adding structure to real property. The vast majority of building construction projects are small renovations, such as an addition of a room, or renovation of a bathroom. Often, the owner of the property acts as laborer, paymaster, and design team for the entire project. However, all building construction projects include some elements in common - design, financial, and legal considerations. Many projects of varying sizes reach undesirable results, such as structural collapse, cost overruns, and/or litigation reason; those with experience in the field make detailed plans and maintain careful oversight during the project to ensure a positive outcome.

Building construction is procured privately or publicly utilizing various delivery methodologies, including hard bid, negotiated price, traditional, management contracting, construction management-at-risk, design & build and design-build bridging.

Procurement

Procurement describes the merging of activities undertaken by the client to obtain a building. There are many different methods of construction procurement; however, the three most common types of procurement are:

Traditional (Design-bid-build)

Design and Build

Management Contracting

Traditional

This the most common method of construction procurement and is well established and recognized. In this arrangement, the architect or engineer acts as the project coordinator. His or her role is to design the works, prepare the specifications and produce construction drawings, administer the contract, tender the works, and manage the works from inception to completion. There are direct contractual links between the architect’s client and the main contractor. Any subcontractor will have a direct contractual relationship with the main contractor.

Design and build

This approach has become more common in recent years and includes an entire completed package, including fixtures, fittings and equipment where necessary, to produce a completed fully functional building. In some cases, the Design and Build (D & B) package can also include finding the site, arranging funding and applying for all necessary statutory consents.

The owner produces a list of requirements for a project, giving an overall view of the project’s goals. Several D&B contractors present different ideas about how to accomplish these goals. The owner selects the ideas he likes best and hires the appropriate contractor. Often, it is not just one contractor, but a consortium of several contractors working together. Once a contractor (or consortium/consortia) has been hired, they begin building the first phase of the project. As they build phase 1, they design phase 2. This is in contrast to a design-bid-build contract, where the project is completely designed by the owner, then bid on, then completed.

Kent Hansen, director of engineering for the National Asphalt Pavement Association (NAPA), pointed out that state departments of transportation (DOTs) usually use design build contracts as a way of getting projects done when states do not have the resources. In DOTs, design build contracts are usually used for very large projects.

Management procurement systems

In this arrangement, the client plays an active role in the procurement system by entering into separate contracts with the designer (architect or engineer), the construction manager, and individual trade contractors. The client takes on the contractual role, while the construction or project manager provides the active role of managing the separate trade contracts, and ensuring that they all work smoothly and effectively together.

Management procurement systems are often used to speed up the procurement processes, allow the client greater flexibility in design variation throughout the contract, the ability to appoint individual work contractors, separate contractual responsibility on each individual throughout the contract, and to provide greater client control.

Residential construction

Residential construction practices, technologies, and resources must conform to local building authority regulations and codes of practice. Materials readily available in the area generally dictate the construction materials used (e.g. brick versus stone, versus timber). Cost of construction on a per square meter (or per square foot) basis for houses can vary dramatically based on site conditions, local regulations, economies of scale (custom designed homes are always more expensive to build) and the availability of skilled trades people. As residential (as well as all other types of construction) can generate a lot of waste, careful planning again is needed here.

Heavy/civil construction

Heavy/Civil construction is the process-adding infrastructure to our built environment. Owners of these projects are usually government agencies, either at the national or local level. As in building construction, heavy/civil construction has design, financial, and legal considerations, however these projects are not usually undertaken for-profit, but to service the public interest. However, heavy/civil construction projects are also undertaken by large private corporations, including, among others, golf courses, harbors, power companies, railroads, and mines, who undertake the construction of access roads, dams, railroads, general site grading, and massive earthwork projects. As in building construction, the owner will assemble a team to create an overall plan to ensure that the goals of the project are met.

As you can see, construction work is a very difficult job (but of course, we knew that already). The key point that I am trying to make is that, when someone is working for you, you want for him or her to do the best. Where can you find the best to get the job done? Mmmhmmm, I knew you knew. Repairfinders.com. It is the only place where you can find the very best in the business, in your neighborhood. It gets better, not only will you get an honest, reliable, hardworking individual, but all the businesses in offer free price quotes. Jack is signing off.

 

 

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Do you know the difference between Cement and Concrete? Now...

Today is such a beautiful day! I have always found Thursdays to be a bit boring, but today is such a nice day. I figured that since I am in such a good mood, we could do something “educational”. Instead of giving you the inside scoop today, I am going to give you information. Doesn’t that sound fun? Well let us get to it. Be prepared to learn a lot, because I know you do not know much about cement.

Many people talk about cement when they mean concrete.

Cement is a fine-grained compound that turns into a solid when mixed with water. Cement is used to bind mixtures of materials into a composite solid.

Concrete is a mixture of cement, sand and gravel. That is, cement is the glue of concrete. Now that we have made that clear, let us talk about cement. Cement begins with lime.

Lime, the First Cement

Lime is a substance used since ancient times to make useful things like plaster and mortar. Lime is made by burning, or calcining, limestone-and that is how limestone gets its name. Chemically, lime is calcium oxide (CaO) and is made by roasting calcite (CaCO3) to drive off carbon dioxide (CO2). That CO2, a greenhouse gas, is produced in great quantities by the cement industry.

Lime is also called quicklime or calx (from Latin, where we also get the word calcium). In old murder mysteries, quicklime is sprinkled on victims to dissolve their bodies because it is very caustic.

Mixed with water, lime slowly turns into the mineral portlandite in the reaction CaO + H2O = Ca(OH)2. Lime is generally slaked, that is, mixed with an excess of water so it stays fluid. Slaked lime continues to harden over a period of weeks. Mixed with sand and other ingredients, slaked lime cement can be packed between stones or bricks in a wall (as mortar) or spread over the surface of a wall (as render or plaster). There, over the next several weeks or even years, it reacts with CO2 in the air to form calcite again-artificial limestone!

Concrete made with lime cement is known from archaeological sites in both the New and Old World, some more than 5000 years old. It works extremely well in dry conditions. It has two drawbacks: Lime cement takes a long time to cure, and while the ancient world had lots of time, today time is money.

Lime cement does not harden in water but stays soft, that is, it is not a hydraulic cement. So, there are many situations where it cannot be used.

Ancient Hydraulic Cement

The Pyramids of Egypt are said to contain a hydraulic cement based on dissolved silica. If that 4500-year-old formula can be confirmed and revived, it would be a great thing. However, today’s cement has a different pedigree that is still quite ancient.

Around 1000 BCE, the ancient Greeks were the first to have a lucky accident, mixing lime with fine volcanic ash. Ash can be thought of as naturally calcined rock, leaving silicon in a chemically active state like the calcium in calcined limestone. When this lime-ash mixture is slaked, a completely new substance is formed: calcium silicate hydrate or what cement chemists call C-S-H (approximately SiCa2O4 · xH2O).

C-S-H is still a mysterious substance today, but we know it is an amorphous gel without any set crystalline structure. It hardens fast, even in water. In addition, it is more durable than lime cement.

The ancient Greeks put this new cement to use in new and valuable ways, building concrete cisterns that survive to this day. But Roman engineers mastered the technology and constructed seaports, aqueducts and temples of concrete as well. Some of these structures are as good as ever today, two thousand years later. However, the formula for Roman cement was lost with the fall of the Roman Empire.

Modern Hydraulic Cement

While lime cement continued in use throughout the Dark and Middle Ages, true hydraulic cement was not rediscovered until the late 1700s. English and French experimenters learned that a calcined mixture of limestone and claystone could be made into hydraulic cement. One English version was dubbed “Portland cement” for its resemblance to the white limestone of the Isle of Portland, and the name soon extended to all cement made by this process.

Shortly thereafter, American makers found clay-bearing limestone’s that yielded excellent hydraulic cement with little or no processing. This cheap natural cement made up the bulk of American concrete for most of the 1800s, and most of it came from the town of Rosendale in southern New York.

Rosendale was practically a generic name for natural cement, although other manufacturers were in Pennsylvania, Indiana and Kentucky. Rosendale cement is in the Brooklyn Bridge, the U.S. Capitol building, most 19th-century military buildings, the base of the Statue of Liberty and many other places. With the rising need to maintain historic structures using historically appropriate materials, Rosendale natural cement is being revived.

True Portland cement slowly gained popularity in America as standards advanced and the pace of building quickened. Portland cement is more expensive, but it can be made anywhere the ingredients can be assembled instead of relying on a lucky rock formation. It also cures faster, an advantage when building skyscrapers a floor at a time. Today’s default cement is some version of Portland cement.

Modern Portland Cement

Today limestone and clay-containing rocks are sintered-roasted together at nearly melting temperature-at 1400° to 1500°C. The product is a lumpy mixture of stable compounds called clinker. Clinker contains iron (Fe) and aluminum (Al) as well as silicon and calcium, in four main compounds:

  • Alite (Ca3SiO5)
  • Belite (Ca2SiO4), known to geologists as larnite
  • Aluminate (Ca3Al2O6)
  • Ferrite (Ca2AlFeO5)

Clinker is ground to powder and mixed with a small amount of gypsum, which slows down the hardening process. And that is Portland cement.

 

 

Making Concrete

Cement is mixed with water, sand and gravel to make concrete. Pure cement is useless because it shrinks and cracks; it is also much more expensive than sand and gravel. As the mixture cures, four main substances are produced:

  • C-S-H
  • Portlandite
  • Ettringite (Ca6Al2(SO4)3(OH)12 26H2O; includes some Fe)
  • Monosulfate ([Ca2(Al,Fe)(OH)6] (SO4,OH,etc) xH2O)

The details of all this are an intricate specialty, making concrete as sophisticated a technology as anything in your computer. Yet basic concrete mix is practically stupid proof, simple enough for you and me to use. You see though we are smarter than that, we will not go around messing with cement and concrete mixes, because we know we should leave that to the professionals. So if you need a professional, check out repairfinders.com where they have only the best in the business, and you will never be let down. Jack is over and out.

 

 

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All about Electricians!

Hello folks at home, I was thinking earlier about something quite profound, it made me chuckle and sigh at the same time. It was about how we underestimate electricians. You see, electricians bring us electricity. They put in the wires that carry electricity through our homes, offices, and factories. They also fix electric machines. Without these workers, there would be no lights, no computers, and no TVs plugged into our walls. So today, let us talk about the complexity of being a hardworking electrician.

An electrician is a tradesman specializing in electrical wiring of buildings and related equipment. Electricians may be employed in the installation of new electrical components or the maintenance and repair of existing electrical infrastructure. How do they do this you say? Well I will tell you! Electricians start by reading maps (called blueprints) that show how electricity flows. Blueprints show where to put wires, electrical equipment, and outlets for plugs. When working on a new building, electricians draw new blueprints. Then, electricians put tubes or pipes inside the walls. They also put small boxes on the walls to hold switches and outlets. They pull wires through the tubes to connect the boxes and make a path for the electricity to follow. A path for electricity is called a circuit. Electricians also add circuit breakers, transformers, and other equipment to control how electricity flows. They make sure the right amount of electricity goes to the machines that use it. Electricians follow strict rules about how to wire buildings. After they finish wiring, electricians use ohmmeters, voltmeters, and oscilloscopes to measure the amount of electricity running through the system. Electricians also install wires for telephones, computers, and fire alarms. Sometimes, they use fiber optic cable.

 

In most countries, the job of an electrician is a regulated trade for safety reasons due to the many hazards of working with electricity, requiring testing, registration, or licensing. Licensing of electricians is controlled through government and/or professional societies. Maintenance electricians fix electric machines or broken wiring. Some focus on houses. They might rewire a house. They could replace an old fuse box with one that can run more appliances. Some electricians work in factories. They might fix motors, generators, and robots. They also inspect equipment and fix it before it breaks. They tell managers when equipment needs to be replaced. Electricians put in new electrical equipment, too. Electricians use wire strippers, knives, hacksaws, and power tools. Some electricians stand for a long time and climb ladders. Some work in dusty, dirty, or hot places. But others work in clean places. They need to be careful to avoid falls, cuts, and electric shock. They need good hand-eye coordination and to be good at seeing the different colors of wire.

As you can see, it is not easy at all to be an electrician. Not only do they have to work in a potentially dangerous environment but they also have to be smart. They have to do very well in math and science. Even after an electrician get their licensing and what not; they still have to spend 3 to 5 years as an apprentice before they are able to stretch out on their own. These are important facts we all must consider. When you are looking for a trained highly qualified electrician the best place to look is… you know this! That is right, repairfinders.com. Why? Because at repairfinders we only list the best in the industry, so not only will you get excellent service, and a hardworking individual, you will also get a reliable electrician for life. So why are you still here reading this? You should be getting free quotes from electricians in your area right now on our site! Until the next time, Jack

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