How Do Cranes Get To The Top Of Skyscrapers - Part 2

Continuing from part 1...

Internal Climbing Method. The second method used at the construction site for raising the tower crane is the internal climbing method. Here the crane, from the beginning of the construction process, is actually placed in the center of the building from where it constructs the skyscraper. As the floors are constructed, the crane is raised along with the construction of the floors from the inside of the building. The internal climbing method generally relies on the construction of the floors. One hydraulic cylinder is placed at the crane base, and this cylinder elevates the crane tower through the building in order to reach a higher floor. Later the construction workers slide steel beams beneath the tower crane to give it a stable footing and the crane begins to rise. But this climbing method requires more time for assembling when compared with the external climbing method. The external and the internal climbing method are mostly applied in the construction of skyscrapers. For example, the World Trade Centers in New York were built by implementing the internal or the external climbing method.

Heavy Lift Helicopter Or Skycrane. The third and the last climbing method involves the use of a heavy lift helicopter or shortly known as a skycrane. The skycrane picks up and lifts crane segments from the ground and moves them to the top of the skyscraper. It is not strange to see a helicopter bringing crane segments at the top of the skyscraper. This is done segment by segment, because the crane segments can have weight up to several tons. But however this method can be very expensive because it requires and involves additional equipment and extra labor effort. And because flying with heavy helicopters above populated areas is very difficult, this method is not widely adopted and it is used only for special construction projects located away from urban areas or for construction works on water.

Bonus Explanation: How Cranes Get Back On The Ground?

Once the construction of the skyscraper is completed, the tower crane needs to be dismantled, literally piece by piece. The process of bringing down the tower crane is opposite to the process of raising the crane. Most of the cranes are designed to be easily dismantled once the construction process is finished. Generally the tower crane hoist up one smaller crane which is paced at the top of the skyscraper. This additional smaller crane is known as derrick. The derrick is used at the rooftop to dismantle the tower crane into smaller parts that can be easily lowered to the ground. A third much smaller crane can be used to dismantle the derrick into smaller pieces. The third crane usually is dismantled by the workers piece by piece, and each piece is small enough to be carried by hands and transported to the ground by the elevators.

How Do Cranes Get To The Top Of Skyscrapers - Part 1

A crane is a lifting device that is used for lifting and moving heavy loads and materials from the ground vertically and horizontally. The crane is vital and integral machine needed for the construction process. The cranes can be found at every construction site. They are standard construction equipment that is necessary for the construction of different kinds of structures like buildings, bridges highways and many other structures. But mostly the cranes are used when a tall skyscraper needs to be constructed. They are needed because they are the only machines that are capable of lifting heavy materials which are needed for the construction of the upper floors of the skyscraper.

The skyscrapers are very complex structures and require special equipment and knowledge. The cranes which are used in the construction of the skyscrapers are known as tower cranes. The base of the crane is actually a concrete slab which is attached to the ground or to the sides of the building. The concrete base is connected to the tower, and at the top there is a control cabin which controls the crane movement. At the big cities it is very common to see cranes on the top of the skyscrapers performing different kinds of construction jobs. One very interesting and intriguing question is how on Earth do they get up there, what mechanisms or methods are used so that cranes can reach the sky?

The most simple explanation will be by using their own hoisting power. The crane uses its own hoisting power to make itself taller. It raises itself section by section, reaching top heights. But actually there are three methods for the tower cranes to get to the top of the skyscraper:

• External climbing method
• Internal climbing method
• Using a heavy lift helicopter or “Skycrane”

External Climbing Method. By implementing this method, the tower crane expands upwards. The base of the tower crane is fixed by using concrete slabs on the ground. The tower of the crane is lifted by using other smaller mobile crane types. Once the building reaches more than 60 meters in height, the tower crane is secured or tied to the building with several steel collars, and other parts are inserted into the backbone of the crane. In order to add segments and other parts by itself, the tower crane is equipped with additional climbing section- a metal sheath. The main function of this metal sheath is to serve as a scale. The metal sheath raises the arm of the crane and supports the arm temporarily while it takes new segment from the arm that needs to be placed. The metal sheath then holds the new segment while the workers on the crane work to put the new segment in place. The same procedure is repeated on every 60 meters or more. The external climbing method is the most commonly used method at the construction sites because it reduces the time required for raising the crane. 

Continue reading to part 2...

Everything You Need To Know About Soil Compaction And Roller Compactors - Part 3

Continuing from part 1 and part 2...

The road roller is a machine that is generally used in the construction of roads and highways. Usually the road roller comes with a roller body and a metal drum. Depending on the model there can be more than one metal drum. Some models come equipped with several wheel instead of drums. These models offer higher maneuverability and can be easily transported from one location to another. One person drives and operates the roller, and in some models the person pushes the roller in order to create flat and smooth surface. Generally speaking the road roller operates when the weight of the metal drum causes the soil to compact and to compress. The actual weight of the drum varies depending on the model. For example, the drum of the manually operated road roller usually has weight of 45kg, and this roller is not used in the construction of big roads or highways but for other small projects like for paving walkways. On the other hand the industrial rollers which are used in the construction of highways and regional roads can have total weight of 25 tons or even more. The actual weight of the road roller comes from the metal drum that is attached to the roller. In some models the total weight of the drum can be increased by adding liquid materials like water.

In some construction projects several different road roller models can be used. For example, at the beginning of the construction process a roller that has wheels instead of drums can be used, and once the ground area becomes smooth and level much bigger and powerful road roller with one or more metal drums can be used to make the ground as compact as possible.

Many different types and models of road rollers are available on the market today with capability to complete different kinds of compaction jobs and each model offers something different. Some road rollers use a water based lubricants for preventing different kinds of materials like asphalt or dirt to stick to the metal drums. Other rollers have vibration mechanisms for higher compaction. The road rollers generally are classified into two categories : static and vibratory rollers. The static road rollers operate by using only the force of the gravity for compaction. They usually have larger weight when compared with the vibratory rollers. The vibratory rollers on the other hand operate by using the force of the gravity and also the force of the vibrations provided by one or more vibrating mechanisms. The most commonly used road rollers at the construction sites are : the manual walk behind roller, powered walk behind roller, trench roller, padfoot roller, the single drum roller, double drum or twin drum roller, single wheeled roller, multi wheel roller or multi tyred roller and many other. 

Everything You Need To Know About Soil Compaction And Roller Compactors - Part 2

Continuing from part 1...

The process of soil compaction is essential for every construction project and task. A soil compactor is one particular piece of machinery that is used for achieving appropriate soil compaction. It is generally a machine or device that is used for reducing the size of the waste material or soil through the process of compaction. The soil compactors are powered by hydraulics and they can be found in many different sizes and shapes. The landfill or the waste compactors have a blade attached on the front, ant they are used to drive over waste material which is deposited by the waste collection vehicles. In the construction industry three main types of compactors are used : plate compactors or jumping jack compactor, road rollers and vibrating road rollers.

The plate compactor is a construction machinery which is mainly used to level and to smooth the earth. It comes with a heavy steel plate attached to the base of the machine, and has some resemblance for a push style or for lawn mover. The plate compactor usually performs a vibrating action in order to level the land beneath the machine. These machines can be used either for home or for business applications. Construction workers and landscapers can use different types and models of plate compactors depending on the job or task. The jumping jack tamper model is especially designed for pounding the earth with high force. The larger models provide more force and power but they are much expensive when compared with the regular models that can be found on the market. In other words the bigger the plate compactor, the bigger pressure it can provide.

The plate compactors are very useful machines for many construction projects. They can be used for earth compaction before paving or as a part for different landscaping projects. This machine is also required when compacting stone, gravel and sand during the process of driveway or road paving. The plate compactors are also used as a machines to smooth and to level small portion of asphalt and to tighten dirt. A plate compactor is one economical and easy to use construction machine that can be used for variety of projects.

The road roller, or also known as roller compactor or simply a roller, is a compactor like machine which is used for the compaction of soil, concrete, gravel and asphalt when constructing roads or foundations. Road rollers are also heavily used in agriculture and at landfills. In some parts of the world the rollers are still known as steam rollers. Although it is considered as a modern piece of construction equipment, the rollers have been used for many years. Animals were used to pull the rollers many years ago. With the industrial revolution the steam engines replaced the animals, and in the 20^th century other sources were used to power the rollers, like the diesel.

Continue reading to part 3...

Everything You Need To Know About Soil Compaction And Roller Compactors - Part 1

The soil compaction is a process in which a particular stress force is applied to the soil, and the process results in densification because the air is displaced from the pores of the soil. When this happens, water or other types of liquids are being displaced from the soil grains. Generally the soil compaction is a process in which the total mass of the ground or soil, mainly consisted out of air and water particles, is being reduced to some extent by applying weight on the soil. Different types of heavy machines are used for the soil compaction process, like compaction roller. But the soil compaction process can occur as a result of the passage of the animal feet. Usually two types of soils are being identified : cohesive and non cohesive. Each type of soil requires appropriate compaction.

The process of soil compaction is very important especially in the construction. A soil that is compacted properly by using the appropriate machines is a priority for every construction project. The compaction process will provide the desired soil characteristics like soil resistance and soil stability. Depending on the type of the soil the process of compaction is different. But no matter what type of soil is being compacted, if the air is not removed from between the soil particles, unwanted or unexpected soil movement can occur later during the construction of buildings, bridges, foundations. Any failure to remove the air will result in higher damages later during the construction process.

There are several methods and techniques for achieving soil compaction. The most commonly used compaction methods are the following ones :

• Static Compaction- when weight is slowly applied on the soil and then it is slowly released.
• Impact Compaction- when the weight is applied directly by dropping mass on the surface of the soil.
• Vibrating Compaction- weight is applied continually and rapidly by using a particular mechanically driven plate compactor or hammer. These machines are often combined with a roller compactor.
• Gyrating- the weight is applied and maintained, while at the same time the soil is a subject to a gyratory motion. This process however is limited only for laboratory applications.
• Rolling Compaction- the compaction of the soil occurs by using one big cylinder which is rolled over the soil. The roller compactors are often equipped with vibratory mechanisms for increased ability.
• Kneading Compaction.

Continue reading to part 2...

History Of Surveying Equipment – Part 2 - Editors Top

History Of Surveying Equipment – Part 2 - Editors Top

Environmental Impact Of Skyscrapers - Part 2

Continuing from part 1

In addition the cooling and the heating systems, and the lights that are used in the skyscrapers consume large amount of energy, and additional energy is required to transfer all these services and materials to the higher floors of the skyscraper. Most of the skyscrapers that are built in the 20^th century are not constructed and designed with appropriate thermal protection and isolation, and also no natural ventilation systems can be found. This means that the skyscrapers are continuously heated during the winter season and continuously cooled during the summer season, and electric ventilation systems are installed to provide breathable air for all who work there.

Today the construction engineers and architects are beginning to design the blueprints of the skyscrapers with sustainable solutions. Cranes that consume lees fuel and other eco friendly construction machines, wind turbines, solar panels, central cooling and heating systems, rain water reuse, recycled construction materials are just few of the modern solutions and ideas that the architects are implementing during the construction of the skyscrapers. Today the architects are experiencing the benefits of the modern GPS surveying equipment in order to gather accurate data in no time. For a positive impact to the environment, the architects realize that all of the materials that are used in the construction of the skyscraper need to be closely analysed, studied and modified in order the skyscrapers to be considered as eco-friendly and ecologically approved.

But however, the modern technology isn't the only answer to all questions related to the construction of the skyscrapers. The architects and the construction engineers should not be fooled with this, they should not be tricked that only the technology can solve all of their problems and issues towards designing ecological skyscrapers. The ecological design of the skyscraper needs to provide a balance between the technology used in the construction process and the environment or the nature. The ecological design means that all environmental aspects and issues should be closely considered at all stages of the construction process. The consumption of raw and non renewable materials that are used in the building process, carbon emissions and increased pollution from the construction machines, and the waste materials are the main environmental aspects that need to be considered during the construction of the skyscrapers.

Saving and preserving clean environment is the most important issue today. Because the architects and the construction engineers design the world in which we live in, they can shape the way we live by constructing and designing greener and cleaner buildings. If architects can design and construct with sustainable and ecological solutions in mind, the end result will surely have a positive impact on the environment.