12/26/10

طريقة سريعة لتقوية شبكة فودافون

تعبت من ضعف الشبكة ومش عارف تتكلم او تسمع كويس ؟؟ 
شوف الحل ده وجربه

11/28/10

Beam Bridge

Beam Bridge is the simplest bridge in its construction and its cost. It also can be called Girder Bridge as it consists of one girder and it is the main part of it. The beam bridge rests at its ends on supports called abutment, and if the span is tool long to be covered by one girder, then multiple girders are used and supported by piers in the mid of main span or depending on the piers number.


Beam Bridge is the first type man invented, in the old times; they used wood logs as bridges to span the rivers. Now the construction materials have been developed, like steel and reinforced concrete. The steel box girder and the concrete one is very efficient in this type of bridges


The forces on the bridge girder is two types, tension at the lower side and compression at the upper side, the weight of the bridge and of  the vehicles on it is transferred through the girder to the abutments to the soil. The limitation of this bridge is represented in its length as it can't support large spans because of the deflection effect. The longest girder bridge is "Lake Pontchartrain Causeway" which is located at Louisiana state in the us, its whole length is 38.35 km divided into single spans of length 17 m each  

11/27/10

Erosion

Erosion refers to the process of weathering and transporting the materials around the earth like soil and rock. The erosion force usually occurs by the wind, water and natural slopes or some chemicals like acid rain


Although the erosion process is from the nature but lately it has been increased because the wrong behaving of human in dealing with nature resources, these like deforestation and the huge industrial revolution



One of the main causes of erosion is the gravity effect, on edged or creep sloped areas, the particles leave its places from higher levels to lower land due to gravity. The obvious example for erosion caused by the force of water is the shores erosion, it happens because of the tides effect. On very huge scale, erosion can happen by the movement of crust (the outer layer of the earth), in this case, erosion is caused by Tectonic effects

Caissons

A caisson is a structure used in construction
particularly underwater projects like bridge or dam construction. It is constructed to provide a dry, protected environment for workers and
construction materials


The caisson is generally a box like structure with an open bottom and open top some times. The structure keeps water out of the construction area while its open bottom allows workers to place foundations and piers in the sea bed or riverbed. An open caisson can be used in shallow water; its open top allows light and air to enter from above the water line

  For deep-water construction, a pneumatic caisson has a closed top; pressurized air is  pumped in, and personnel enter and leave through an airlock. Both types have sharp inclined lower edge, which allows the caisson to be deeply embedded in the ground

Before putting the caisson in its place, engineers look for stable seabed like rock. But if they don’t find this layer they make artificial layer to  provide safety to the caisson. In pneumatic caissons, an airlock allows access to the chamber and the pressurized air flow must be constant to ensure regular air changes for the workers and prevent excessive inflow of mud or water at the base of the caisson

For getting out the consumed material and excavation ashes, the workers use muck tube connected to the surface. A crane at the surface removes the soil with a clam shell bucket

Know About Aerial Lift


The Duluth aerial lift bridge is located across the canal that is the main entry to the Duluth harbor from Lake Superior.it is a major landmark in the port city of Duluth, Minnesota

The design of this bridge was the winner design from John Alexander Low Waddell who drew up plans for vertically lift bridge. when Duluth residents dug through the narrow slit of land known as Minnesota Point to create a harbor at the head of the Great Lakes

As suitable as the shipping canal was for the city, it left citizens on the Point cut off from the mainland. In 1892 Duluth held a competition for a bridge design that would enable residents to cross without interrupting traffic in the shipping lane. The winning design came from  John Alexander Low Waddell who drew up plans for a high-rise vertical lift bridge which was the first of this type

But the Duluth project was cancelled before construction began and Waddell’s design was later built in Chicago. In 1905 Duluth finally built its bridge. When it was completed in 1905, the Aerial Bridge's gondola had a capacity of 60 short tons and could carry 350 people plus wagons, streetcars, or automobiles

The bridge can be raised to its full height in almost 3 minutes, and goes up 25 to 30 times daily during busy shipping season. The span is about 390 feet(120 m). As ships pass, there is a customary horn-blowing sequence which is copied back. Long-short-long-short means to raise the bridge, and Long-short-short is a friendly salute. Its language between the bridge and the coming ship

What Is Air Compressor?




The use of air compression for construction tools is very convenient because they  normally use the energy of compressed air as opposed to electricity. Of course, when using a pneumatic
power tool, you will need an air compressor


Most air compressors run on diesel, and basic maintenance checks should always be conducted before operation. The power of compressed air can be dangerous, and caution must always be taken when an air compressor is in use. There are strict safety rules to abide by when using pneumatic power tools

The air hose must be checked for cracks or holes, and if anything suspicious is found, the hose must be replaced immediately. Before you connect the air hose to the air compression outlet, open the valve. After doing this connect the tool’s hose to the outlet and then ensure that the hose is clear of any water or foreign objects before you connect the hose to the power tool

Air breakers are designed for general demolition, and are probably one of the most popular pneumatic power tools on the market. An air breaker will be used to break medium and hard materials such as concrete and  asphalt. Prior to operation of an air breaker, you must always  check that all parts are securely fastened

A rock drill is probably another popular pneumatic power tool you will come across if you are using an air compressor to power  your construction work. as example for that, the shotcrete application and also the soil nailing uses the air compressor power to drive the piles into the soil



Rock Drill

rock drill
A rock driller is a piece of equipment used for drilling the rocks. A rock drill is designed for heavier jobs such as bench and secondary drilling

there are so many reasons to drill rocks, such as soil nailing which means reinforcing the retaining walls to the rocky side by piles embedded into the rock, aslo this is used for different construction purposes like footing  lying and fixing equipment. and can also be used for drilling for smooth
blasting


The teeth of the rock driller have to be very sharp to cut the rocks without being damaged, and for that purpose, the alloy used for making these teeth consists of steel and  Powder of diamond. the driller arm is fitted to powering system which is carried on crawler or wheeled vehicle and often is powered by hydraulic system. There are some rock drills that can drill holes up to 6 meters deep



Petroleum Drilling

Drilling for oil  is one of the most important things in any economy, as oil means life for most industries. It can make a poor country rich in very short time.As the world is running out of this source of energy it is getting more value than ever. And we can notice the positive effect of oil extraction on Arabic  countries economy and other oil deposits around the world



The drilling operation requires high technique engineering and expert people  to get the job done in perfect way. It is a heavy industry needs  heavy equipment. On the scientific face it also very useful, geologists can identify the geologic reservoirs through the oil. It gets in almost every industry, for example, fuel for vehicles and factories and allot of things run on gas or oil, clothes made from chemical fibers , roads asphalt, and so many things that nobody can imagine


Though nothing have only good staff specially at dealing with the nature, it is very dangerous and carry a lot of risks during and after the extracting. The next video show animation explanation of the extraction process

Motor Grader usage






Motor grader is construction equipment that is used in flatting and accurate finishing of the final outlets of surfaces before putting the pavement layer. It comes in all sizes and types. This equipment has a blade between the front and rear parts. The blade is controlled either mechanically or hydraulically, the blade can be extended from any side of the grader, both ends of the blade can also be raised or lowered depending on the desired job

Due to weather and using conditions, roads get damaged and became in need for repaving. Here comes the role of motor grader as it flattens the road before the pavement layer is laid. Also they are used in removing falling rocks from roads in cliffs areas 

Motor graders can do more than one job. So they can replace several other equipment .and used in road paving stage as it spread the material over the road area in equal. As a result of all that companies prefer using motor grader



how to drive amotor grader


Driving motor grader isn't so hard. This heavy equipment have a lot of controllers to handle the big power and use it in optimum way to get the best results. But these controllers represented in joysticks and some buttons are easy to remember and also sensitive as it responds immediately when it moved or pressed. 

Not many people have a chance of driving a motor grader but who knows what can happen. It's so fun to drive such a huge equipment like motor grader but also very dangerous because if it got out of control, it can cause a serious damage. So for first time you can get help from  professional driver. And for more safety this must be done in open area. The next video show simple learning to driving  a motor grader so enjoy it



Offshore Drilling



 petroleum drilling in water

Offshore petroleum drilling is drilling for oil under the ocean bed. And for that purpose  companies use special techniques and advanced platforms designed precisely to be steady on the water surface 

There are massive oil deposits under the ocean bed that make companies of oil extraction Obsessed to get it out.the first offshore oil drilling was in 1938 in the area of the gulf of Mexico. After that people know that something called offshore oil drilling and began to search for it around the world under the ocean floor. On the other hand, many people have an opposition of this kind of drilling due to its environmental bad effect and also the oil spills  on the coasts. 
The process of extraction varies a lot, depending on the depth and also on the suitable platform, floating or fixed or in case of best mobility it may be ships conducted to the underneath pipes. But every thing from the nature has a price,  offshore drilling operation is very dangerous and if something wrong happened the results can be catastrophic, besides it carry the danger of pollution. And for live example of that we can't forget the terrible  accident of the gulf of Mexico. the next video show an animation of how pipes driven in water

Soil Testing

foundation types
Soil testing means the analysis of soil samples to determine its composition and other characteristics like its behavior under different loading circumstances and the nature of its formation. Soil characteristics can vary from one spot to another in the same place

So, in soil testing many samples from different places should be taken and tested to have aright judgment on the soil.Soil tests is preliminary and very important step in construction projects. Depending on the soil results that came from commercial lab, engineers make their decision about the foundation type

Not only the construction projects that  need the soil testing, but there are also farmers or gardeners, they use soil testing to know minerals percentage and pH balance in the soil. Also some environmental agencies do soil tests to monitor problem areas for pollution and released contaminants, and to check environmental remediation programs. 

About Cranes

Cranes are lifting machines that use levers and pulleys to lift very big weights. These machines are very old in its history, it's not an invention from the modern industry but in fact they have been used over the last 2000 years. It was invented by the ancient Greeks



At that time there was no hydraulic power or steam engines to power these cranes, so it was powered by men and powerful animals in some times. The Greeks used cranes made of wood to build their monuments so they are the original inventors of this great machine. Also the ancient Egyptians used simple cranes to build the pyramids. After that by a short time a larger cranes were invented and widely used in lifting weights 


The widespread use of cranes and derricks had to wait the development in the steam engine to provide power. steam cranes became common in the 19 th century.  Cranes were also used in harbors to load and unload ships and were used in train stations too for the same reason. By the coming of the industrial revolution, the material of building cranes was changed from wood to steel. modern cranes are now constructed of steel and use wire ropes for both lifting and bracing


Not only the material has changed, but also the powering system changed from men or animals and steam engines to electric motor and hydraulic systems. Cranes are used in a lot of aspects, such as in construction for lifting materials and to speed the construction process. In industry, they used in assembling and lifting heavy things. In harbors and train stations, for loading/unloading ships and trains and many heavy work


with the modernizing of almost everything, many work activities came up and many changes in our living style too, and as a result, many types from cranes ere invented to suit different purposes



there is also a type of tower crane called self erecting crane
and a type of gantry crane called overhead crane

Truck Mounted Crane


The truck mounted crane is one of the mobile cranes, as it is mounted on truck. These cranes can travel at high speed on highways, which makes them a good choice for quick need for such equipment. For its own stability, the truck-mounted crane use counterweights. 


And also for stability in job sites, there are triggers  hold the crane to the ground. This crane's construction is similar to many other cranes, it consists of the rotating body mounted on the truck. This body supports the boom. The boom may be telescopic or jointed sections. As for the powering system, may be hydraulic or electric. 

For avoiding the over turning of the crane, these cranes are tested at the factory first. They are fixed by the outriggers and loaded with different loads until it reaches its maximum value. Their capacity ranges between (14.5 and 1300 short ton) and between ( 12.9 and 1161 long ton). The advantage of this crane is the mobility and high speed. But it can't serve ragged places and un flatted areas.


Railroad Crane



Rail road crane is one of the mobile cranes type. The name tells us that this crane runs on rail tracks. It is mobile but in limited way as it can't serve areas out of its operating area. We can see this type at train station, as it used in maintenance work. Also it is uses in accidents recovery operations and freight loading in goods yards

A railroad crane is specifically designed with flanged wheels so it can travel along railroad tracks. Although the design differs according to the type of work, the basic configuration is the same  in all cases which is a rotating crane body is mounted on a sturdy chassis fitted with flanged wheels

The body supports the boom of the crane and contain all mechanism of lifting and operating.The first appearing of these cranes was at 1910, the year of cranes development. In  1990s a new generation of railway cranes was developed. The new generation had a professional high speed railway chassis for up to 75 mph. The superstructure is also diesel hydraulic with telescopic boom and counterweight and designed to the railway's specific needs

Floating Crane



Floating crane is one mobile crane, they are sea vessels have cranes mounted on them or ships equipped with cranes but not like deck cranes. They are mainly used in building bridges and port construction. 


They are capable of carrying whole sections of bridge through the water and installing it in position due to their loads capacity which exceeds 10,000 ton their capacity of loading is great. These types of missions are often made increasingly difficult by rough sea conditions. It requires an experienced operator and crew to complete successfully a lift in these conditions. 

These cranes are also used in salvaging sunken ships and other offshore operations. These cranes speed the work at the oil rigs construction. The floating cranes type was known in 1920, since this date, they are widely used in all offshore construction. The massive weight of these cranes gives them the stability in water. 

The floating cranes work with the electric system for powering wire ropes that lift the loads. The earliest floating crane designs were no more than old ships converted to include a large crane mounted on the deck.   

Aerial Crane



Aerial cranes are helicopters used for lifting weights. they are one of the mobile cranes type.Also they are called sky cranes. These helicopters lift the loads by its long cables. They are used in remote and accessible places where
it is very hard to get any crane type. 


These places like buildings tops, hill or mountain top and other places that cost a lot of money and time to get any other crane like telescopic or tower crane. This type of crane was first used in 1950 by a  plane "Bell 47" but this type of lifting was not popular until 1960. after that the planes companies started to design special helicopters for lifting and moving loads which are called sky cranes. Then they were used in construction for loading many utilities on building roofs such as conditioning systems and water reservoirs and any other materials needed. 

Sky cranes also can be used in fire fighting in far forests, the helicopter has a bucket attached to a rope connected to the plane. The helicopter fills the bucket from near lake or river and then empties the water on the fire from the above. They are very effective in this field as they also used in rescuing operations. 

The aerial cranes are economical and quick in their work, but nothing is all good, they also have some disadvantages, like the load limit they can lift and the skills needed near this crane. The pilot has to be very clever to avoid terrible accidents. in the next video,aerial crane is used for rugged area.

Crawler Crane


Crawler crane is a mobile crane; it consists of
track based vehicle and attached crane apparatus over it. The set of tracks gives the crane high stability in its position. These cranes are able to work on soft ground due to the weight dispersal properties of the tracks

The crane with crawlers can lift bigger weights than the one with rubber wheels. The crawler crane has a main advantage that it can move around the site freely without fixing problem. It also can move with the weight lifted by its ropes.  But the disadvantage of the crawler crane is the enormous weight and the great size. Some of them are very large, so they must be taken apart and moved from site to another by truck or train. 

The massive size gives the crane the ability of lifting massive loads can reach 3500 ton to big heights. For lifting these cranes generally use wire ropes connected to electric motor and may be a combination with  hydraulic power. They can work at any type of land and any type of weather. Their high stability on the ground is because the big contact area between the crawlers and the ground.

Tower Crane


Tower crane is the most common crane in construction sites It is one of the fixed cranes' type. It consists of two main parts, the mast of the crane is fixed through the base to the ground on a concrete slab or on the building sides. The upper part which is the horizontal jib is the part used for lifting. The upper jib is divided in two parts, one long and the other is short. 


The long part is responsible for lifting and moving weights. The short jib is used for keeping balance of the crane. This short part is loaded with concrete blocks or steel weights to keep the stability on both sides of the jib. The crane uses wire ropes for both lifting and bracing weights. These ropes are connected to electric engine. There is operator chamber for operating the whole crane. This chamber can be at the top of the mast under the horizontal jib or attached to the turntable. 

Some cranes do not have the operator cab installed on it because it's operated through a radio remote control from the ground. For holding the lifted weights, the crane use hook which is hooked to the weights with the workers help. The operator in the cab must communicate with the men on the ground to know when and how to lift the weights. 

This crane reaches the construction site  in pieces then it is assembled by the aid of telescopic crane . when the height needed is bigger than the telescopic crane lifting range , a specific type of tower crane is used . this specific type is called self erecting crane. The tower crane must be fixed to the building walls when the height exceeds 80 meters. 

After the construction is complete, a small crane is lifted to the built tower to disassemble the tower crane. There are reasons for this crane to be number one in construction projects such as 1-stability   2- carry massive loads for great heights  3- it speeds the work very well. But nothing is all good, it has some disadvantages too like the high cost and the many precautions should be taken near this crane

Telescopic crane

Telescopic crane is one of the fixed types of cranes that need stability by fixing to the ground while working. Some of us can get confused between telescopic and loader crane, but no, there is an obvious difference between these two 

The loader crane's arm consists of jointed sections that unfold to increase the arm length, some of these sections may be telescopic. But in telescopic crane, the arm which consists of number of tubes fitted one inside the other is one piece often powered by hydraulic system that extracts the tubes to change its length

This type of cranes can also be truck mounted crane if it is put on crane. This modification gives it the ability of being mobile crane. Telescopic cranes are used in construction for short term usage, rescue operation, lifting damaged cars off the road and also in putting heavy items like transmission towers and steel columns in place


Gantry Crane

gantry crane ( twin girder
Gantry crane is a type of overhead crane and one of the fixed cranes' type. But this crane can't move either working or not, it is fixed in its position the supports holding the crane up are fixed in location. Then how it serves weights if it can't move? Well, the weights must come to the crane's operating area. It has a hoist in a fixed machinery house that runs horizontally along rails

The hoist is fitted on one beam for mono girder and two beams for twin girder. On the gantry rail, the crane frame which is supported on gantry system runs forward and backward to lift the weights. Gantry cranes are very common in factories as it moves along certain product assembling line. We can see gantry crane at shipping ports

They are used in loading containers on and off the ships. Because it is fixed at the edge, the trolley or machinery house travels on cantilevered rail at the top of the crane. In the previous case gantry crane can be called container crane.the difference between container and gantry is that container crane can move horizontally while gantry one can't.

Deck Crane


Deck crane a fixed crane, this type of cranes is fixed to the ships or boats deck. This gives the ship advantage as it can load it self without the help of gantry crane or container crane. The ship with deck crane can be used for cargo operation and loading/unloading from shores without loading facilities.

Also it can be used for shipping other ships in water. This type is powered by many systems such as hydraulic system and electric system. Deck crane consists of two main parts, the first is the one fixed to the ship deck and the other is the crane's arm that moves in horizontally and vertically to control the load as desired. 

These cranes were first used on offshore oil platforms In loading equipment from ships to the platform and oil barrels to the ships. The only disadvantage is that it is fixed, that force loads to come to its operating area to lift them besides the weight of the crane which is not an issue for huge ships. The length for loading arm is very important, it gives bigger operating radius. The arm's range is from five m to 18 m in hydraulic cranes

Loader Crane

Loader crane is one of the fixed cranes type. It consists of two main parts, the articulated arm which is fitted to a truck or trailer. The fitted arm consists of jointed section that can be folded when crane is not in use

Some of these sections may be telescopic to add more length to the crane's arm and also durability .The loader crane is powered by hydraulic system that makes it strong enough to deal with big weights. This type of cranes is used for loading and unloading goods from the vehicles' trailer , so it is the optimum crane for goods  transfer companies and any other similar circumstances

The loader crane often has a degree of self control, as it can stow itself and unload goods without the operator instructions. The range of loading for the loader crane varies among light capacity (< 10 ton/m), medium capacity (10—23ton/m) and high capacity (> 23 ton/m). It is also known with the name of boom crane.


Overhead Crane


overhead crane
Overhead crane is fixed crane and similar in its work to gantry crane. From its name, this type of cranes is fixed over the head of the purpose needed to be lifted. The mechanism of lifting and moving weights relies on the upper part of the crane called trolley 

This trolley carries the operating mechanism and runs on single or double beam. The beams are supported by the sides of the crane. These cranes are capable of lifting very heavy weights and huge volumes

So we can easily see them in ports all over the world for loading and unloading ships, the ships get in position and the cranes do their jobs. Also they are used in heavy industries factories like steel mills. The overhead crane can be built inside the construction. Being fixed gives the crane great stability, but some cranes builders add wheels to them for more flexibility. There are small size of these cranes that they can be used in a house workshop and small business. Also they are called the suspended cranes