Burj Khalifa(U A E)

IMAGES

Concept of Burj Khalifa:

The main structure of the building is based on "organic inspiration", taken from the HYMENOCALLIS flower.
Like petals from a stem, the tower's wings extend from its central core.
No stranger to Middle Eastern design, architect Adrian Smith incorporated patterns from traditional Islamic architecture. But his most inspiring muse was a regional desert flower, the Hymenocallis, whose harmonious structure is one of the organizing principles of the tower's design.







CONSTRUCTION DETAILS

•                                             FLOORS      :    163
•                                             HEIGHT       :    829.8m
•           CONSTRUCTION STARTED      :    06/01/2004
•                                              OWNER      :     Emaar Properties
•                                    ARCHITECTS      :     Skidmore Owings and Merrill of Chicago
•                              COMPLETED ON      :     01/10/2009
•                                      OPENED ON      :     04/01/2010
•                                    TOTAL AREA      :     490 acre (198.29hectare)
•            TOWER CONSTRUCTION'S      :     AL Ghurair Investment Group
•                         CONSTRUCTED BY      :     Samsung Engineering & Construction                                                                                    (Belgium)
•                                    TOTAL COST       :     $1.5 billion
• CHIEF STRUCTURAL ENGINEER       :       Bill Baker

BRANCHES OF CIVIL ENGINEERING

                             

Architectural engineering

                            Architectural engineering, also known as building engineering, is the application of engineering principles and technology to building design and construction. Architectural engineers create much of the physical environment in which we all work, live. and play. gaining and honing the needed analytical and design abilities is challenging and never ending . in a course on construction materials and methods , you"ll learn about construction process, building codes, and working with concrete metals, wood and plastics. you might visit a construction site and then write about the choice the architects and engineers have made / you could design a building in detail and might even get to build part of it. 

Construction engineering

Construction engineering is a professional discipline that deals with the designing, planning, construction, and management of infrastructures such as highways, bridges, airports, railroads, buildings, dams, and utilities.The entire environment of homes, buildings, roads, freeways, bridges, and much more result from the delivery of construction projects. It is the responsibility of the construction engineer and construction manager to deliver these projects in a manner that maximizes value – a quality product at a fair price, safely constructed in a timely fashion. This final step in the development of our infrastructure – construction – is one of the most visible products in all of engineering.

Earthquake engineering

Earthquake engineering or engineering seismology is an interdisciplinary branch of engineering that searches for ways to make structures, such as buildings and bridges, resistant to earthquake damage. The focus of our Earthquake Engineering practice is two-fold: post-earthquake investigations of causative mechanisms resulting in structural damage, failure, or collapse; and earthquake planning and risk mitigation, which includes identification, quantification, and mitigation of risk through optimal repair strategies, performance-based upgrades, and customized solutions. We offer multi-faceted holistic support to property owners, insurance and legal communities, and government agencies, both in the aftermath of earthquakes and in pre-earthquake planning and mitigation.

Hydraulic engineering

Hydraulic engineering as a sub-discipline of civil engineering is concerned with the flow and conveyance of fluids, principally water and sewage. One feature of these systems is the extensive use of gravity as the motive force to cause the movement of the fluids.hydraulics engineering is a field within the civil engineering discipline that addresses the control and management of water resources. As a hydraulic engineer, you"ll plan and manage the flow and storage of water.

Mining engineering

Mining engineering is an engineering discipline that involves the practice, the theory, the science, the technology, and application of extracting and processing minerals from a naturally occurring environment. Mining Engineers design mines and will use engineering principles, technology and scientific theory for the safe and effective extraction of natural resources from these mines. Mining Engineers plan, design and operate the mining processes, both underground and above ground. Mining Engineers will be responsible for the overseeing of both mining operations and miners, and are employed by many mining-related organizations.

Mining Engineers will often work with Geologists and Metallurgical Engineers to find and evaluate new mineral deposits. Some Mining Engineers will be involved in the development of new equipment or direct mineral-processing operations to separate minerals from dirt, rock, and other materials.

Transportation engineering

Transportation engineering or transport engineering is the application of technology and scientific principles to the planning, functional design, operation and management of facilities for any mode of transportation in order to provide for the safe, efficient, rapid, comfortable, convenient, economical. Transportation has always played an essential role in the development of society, originally with regard to trade routes and harbours, but more recently with regard to land- and air-based systems as well. It is the transportation engineer's responsibility to plan, design, build, operate and maintain these systems of transport, in such a way as to provide for the safe, efficient and convenient movement of people and goods.

 Geotechnical engineering 

Geotechnical engineering is a civil engineering discipline that is concerned with building on, in, or with soil and rock. Geotechnical engineers design dams, embankments, cuts, foundations, retaining walls, anchors, tunnels, and all other structures directly interacting with the subsoil, both onshore and offshore. Geotechnical engineering is the branch of civil engineering concerned with the engineering behavior of earth materials. Geotechnical engineering is important in civil engineering, but also has applications in military, mining, petroleum  and other engineering disciplines that are concerned with construction occurring on the surface or within the ground. Geotechnical engineering uses principles of soil mechanics and rock mechanics to investigate subsurface conditions and materials; determine the relevant physical mechanical and chemical properties of these materials; evaluate stability of natural slopes and man-made soil deposits; assess risks posed by site conditions; design earthworks and structure foundations; and monitor site conditions, earthwork and foundation construction.

Worker Safety Series

1. Construction
2. Nearly 6.5 million people work at approximately 252,000 construction sites across the nation on any given day. The fatal injury rate for the construction industry is higher than the national average in this category for all industries.
3. Potential hazards for workers in construction include:

1. Falls (from heights)       
2. Trench collapse;
3. Scaffold collapse;
4. Electric shock and arc flash/arc blast;
5. Failure to use proper personal protective equipment; and
6. Repetitive motion injuries.
7. 
   
8. Hazards & Solutions
9. For construction, the 10 OSHA standards most frequently included in the agency's citations in FY 2004 were:
10. Scaffolding
11. Fall protection (scope, application, definitions)
12. Excavations (general requirements)
13. Ladders
14. Head protection
15. Excavations (requirements for protective systems)
16. Hazard communication
17. Fall protection (training requirements)
18. Construction (general safety and health provisions)
19. Electrical (wiring methods, design and protection)
20. 
    
21. Scaffolding
22. Hazard: When scaffolds are not erected or used properly, fall hazards can occur. About 2.3 million construction workers frequently work on scaffolds. Protecting these workers from scaffold-related accidents would prevent an estimated 4,500 injuries and 50 fatalities each year.
23. Solutions:

1. Scaffold must be sound, rigid and sufficient to carry its own weight plus four times the maximum intended load without settling or displacement. It must be erected on solid footing.
2. Unstable objects, such as barrels, boxes, loose bricks or concrete blocks must not be used to support scaffolds or planks.
3. Scaffold must not be erected, moved, dismantled or altered except under the supervision of a competent person.
4. Scaffold must be equipped with guardrails, midrails and toeboards.
5. Scaffold accessories such as braces, brackets, trusses, screw legs or ladders that are damaged or weakened from any cause must be immediately repaired or replaced.
6. Scaffold platforms must be tightly planked with scaffold plank grade material or equivalent.
7. A "competent person" must inspect the scaffolding and, at designated intervals, reinspect it.
8. Rigging on suspension scaffolds must be inspected by a competent person before each shift and after any occurrence that could affect structural integrity to ensure that all connections are tight and that no damage to the rigging has occurred since its last use.
9. Synthetic and natural rope used in suspension scaffolding must be protected from heat-producing sources.
10. Employees must be instructed about the hazards of using diagonal braces as fall protection.
11. Scaffold can be accessed by using ladders and stairwells.
12. Scaffolds must be at least 10 feet from electric power lines at all times.
13. Fall Protection
14. Hazard: Each year, falls consistently account for the greatest number of fatalities in the construction industry. A number of factors are often involved in falls, including unstable working surfaces, misuse or failure to use fall protection equipment and human error. Studies have shown that using guardrails, fall arrest systems, safety nets, covers and restraint systems can prevent many deaths and injuries from falls.
15. Solutions:

1. Consider using aerial lifts or elevated platforms to provide safer elevated working surfaces;
2. Erect guardrail systems with toeboards and warning lines or install control line systems to protect workers near the edges of floors and roofs;
3. Cover floor holes; and/or
4. Use safety net systems or personal fall arrest systems (body harnesses).
5. Ladders
6. Hazard: Ladders and stairways are another source of injuries and fatalities among construction workers. OSHA estimates that there are 24,882 injuries and as many as 36 fatalities per year due to falls on stairways and ladders used in construction. Nearly half of these injuries were serious enough to require time off the job.
7. Solutions:

1. Use the correct ladder for the task.
2. Have a competent person visually inspect a ladder before use for any defects such as:
1. Structural damage, split/bent side rails, broken or missing rungs/steps/cleats and missing or damaged safety devices;
2. Grease, dirt or other contaminants that could cause slips or falls;
3. Paint or stickers (except warning labels) that could hide possible defects
.
3. Make sure that ladders are long enough to safely reach the work area.
4. Mark or tag ("Do Not Use") damaged or defective ladders for repair or replacement, or destroy them immediately.
5. Never load ladders beyond the maximum intended load or beyond the manufacturer's rated capacity.
6. Be sure the load rating can support the weight of the user, including materials and tools.
7. Avoid using ladders with metallic components near electrical work and overhead power lines.
8. Stairways
9. Hazard: Slips, trips and falls on stairways are a major source of injuries and fatalities among construction workers.
10. Solutions:

1. Stairway treads and walkways must be free of dangerous objects, debris and materials.
2. Slippery conditions on stairways and walkways must be corrected immediately.
3. Make sure that treads cover the entire step and landing.
4. Stairways having four or more risers or rising more than 30 inches must have at least one handrail.

5. Head Protection

   Hazard: Serious head injuries can result from blows to the head.

   Solution:

   • Be sure that workers wear hard hats where there is a potential for objects falling from above, bumps to their heads from fixed objects, or accidental head contact with electrical hazards.

   
   

   Safety Checklists

   The following checklists may help you take steps to avoid hazards that cause injuries, illnesses and fatalities. As always, be cautious and seek help if you are concerned about a potential hazard.

   Personal Protective Equipment (PPE)

   Eye and Face Protection

   • Safety glasses or face shields are worn anytime work operations can cause foreign objects getting into the eye such as during welding, cutting, grinding, nailing (or when working with concrete and/or harmful chemicals or when exposed to flying particles).
   • Eye and face protectors are selected based on anticipated hazards.
   • Safety glasses or face shields are worn when exposed to any electrical hazards including work on energized electrical systems.
   Foot Protection
   • Construction workers should wear work shoes or boots with slip-resistant and puncture-resistant soles.
   • Safety-toed footwear is worn to prevent crushed toes when working around heavy equipment or falling objects.

   Hand Protection

   • Gloves should fit snugly.
   • Workers wear the right gloves for the job (for example, heavy-duty rubber gloves for concrete work, welding gloves for welding, insulated gloves and sleeves when exposed to electrical hazards).

   Head Protection

   • Workers shall wear hard hats where there is a potential for objects falling from above, bumps to their heads from fixed objects, or of accidental head contact with electrical hazards.
   • Hard hats are routinely inspected for dents, cracks or deterioration.
   • Hard hats are replaced after a heavy blow or electrical shock.
   • Hard hats are maintained in good condition.

   Scaffolding

   • Scaffolds should be set on sound footing.
   • Damaged parts that affect the strength of the scaffold are taken out of service.
   • Scaffolds are not altered.
   • All scaffolds should be fully planked.
   • Scaffolds are not moved horizontally while workers are on them unless they are designed to be mobile and workers have been trained in the proper procedures.
   • Employees are not permitted to work on scaffolds when covered with snow, ice, or other slippery materials.
   • Scaffolds are not erected or moved within 10 feet of power lines.
   • Employees are not permitted to work on scaffolds in bad weather or high winds unless a competent person has determined that it is safe to do so.
   • Ladders, boxes, barrels, buckets or other makeshift platforms are not used to raise work height.
   • Extra material is not allowed to build up on scaffold platforms.
   • Scaffolds should not be loaded with more weight than they were designed to support.

   Electrical Safety

   • Work on new and existing energized (hot) electrical circuits is prohibited until all power is shut off and grounds are attached.
   • An effective Lockout/Tagout system is in place.
   • Frayed, damaged or worn electrical cords or cables are promptly replaced.
   • All extension cords have grounding prongs.
   • Protect flexible cords and cables from damage. Sharp corners and projections should be avoided.
   • Use extension cord sets used with portable electric tools and appliances that are the three-wire type and designed for hard or extra-hard service. (Look for some of the following letters imprinted on the casing: S, ST, SO, STO.)
   • All electrical tools and equipment are maintained in safe condition and checked regularly for defects and taken out of service if a defect is found.
   • Do not bypass any protective system or device designed to protect employees from contact with electrical energy.
   • Overhead electrical power lines are located and identified.
   • Ensure that ladders, scaffolds, equipment or materials never come within 10 feet of electrical power lines.
   • All electrical tools must be properly grounded unless they are of the double insulated type.
   • Multiple plug adapters are prohibited.
   Floor and Wall Openings
   • Floor openings (12 inches or more) are guarded by a secured cover, a guardrail or equivalent on all sides (except at entrances to stairways).
   • Toeboards are installed around the edges of permanent floor openings (where persons may pass below the opening).

   Elevated Surfaces

   • Signs are posted, when appropriate, showing the elevated surface load capacity.
   • Surfaces elevated more than 48 inches above the floor or ground have standard guardrails.
   • All elevated surfaces (beneath which people or machinery could be exposed to falling objects) have standard 4-inch toeboards.
   • A permanent means of entry and exit with handrails is provided to elevated storage and work surfaces.
   • Material is piled, stacked or racked in a way that prevents it from tipping, falling, collapsing, rolling or spreading.

   Hazard Communication

   • A list of hazardous substances used in the workplace is maintained and readily available at the worksite.
   • There is a written hazard communication program addressing Material Safety Data Sheets (MSDS), labeling and employee training.
   • Each container of a hazardous substance (vats, bottles, storage tanks) is labeled with product identity and a hazard warning(s) (communicating the specific health hazards and physical hazards).
   • Material Safety Data Sheets are readily available at all times for each hazardous substance used.
   • There is an effective employee training program for hazardous substances.

   Crane Safety

   • Cranes and derricks are restricted from operating within 10 feet of any electrical power line.
   • The upper rotating structure supporting the boom and materials being handled is provided with an electrical ground while working near energized transmitter towers.
   • Rated load capacities, operating speed and instructions are posted and visible to the operator.
   • Cranes are equipped with a load chart.
   • The operator understands and uses the load chart.
   • The operator can determine the angle and length of the crane boom at all times.
   • Crane machinery and other rigging equipment is inspected daily prior to use to make sure that it is in good condition.
   • Accessible areas within the crane's swing radius are barricaded.
   • Tag lines are used to prevent dangerous swing or spin of materials when raised or lowered by a crane or derrick.
   • Illustrations of hand signals to crane and derrick operators are posted on the job site.
   • The signal person uses correct signals for the crane operator to follow.
   • Crane outriggers are extended when required.
   • Crane platforms and walkways have antiskid surfaces.
   • Broken, worn or damaged wire rope is removed from service.
   • Guardrails, hand holds and steps are provided for safe and easy access to and from all areas of the crane.
   • Load testing reports/certifications are available.
   • Tower crane mast bolts are properly torqued to the manufacturer's specifications.
   • Overload limits are tested and correctly set.
   • The maximum acceptable load and the last test results are posted on the crane.
   • Initial and annual inspections of all hoisting and rigging equipment are performed and reports are maintained.
   • Only properly trained and qualified operators are allowed to work with hoisting and rigging equipment.

   Forklifts

   • Forklift truck operators are competent to operate these vehicles safely as demonstrated by their successful completion of training and evaluation.
   • No employee under 18 years old is allowed to operate a forklift.
   • Forklifts are inspected daily for proper condition of brakes, horns, steering, forks and tires.
   • Powered industrial trucks (forklifts) meet the design and construction requirements established in American National Standards Institute (ANSI) for Powered Industrial Trucks, Part II ANSI B56.1-1969.
   • Written approval from the truck manufacturer is obtained for any modification or additions which affect capacity and safe operation of the vehicle.
   • Capacity, operation and maintenance instruction plates, tags or decals are changed to indicate any modifications or additions to the vehicle.
   • Battery charging is conducted in areas specifically designated for that purpose.
   • Material handling equipment is provided for handling batteries, including conveyors, overhead hoists or equivalent devices.
   • Reinstalled batteries are properly positioned and secured in the truck.
   • Smoking is prohibited in battery charging areas.
   • Precautions are taken to prevent open flames, sparks or electric arcs in battery charging areas.
   • Refresher training is provided and an evaluation is conducted whenever a forklift operator has been observed operating the vehicle in an unsafe manner and when an operator is assigned to drive a different type of truck.
   • Load and forks are fully lowered, controls neutralized, power shut off and brakes set when a powered industrial truck is left unattended.
   • There is sufficient headroom for the forklift and operator under overhead installations, lights, pipes, sprinkler systems, etc.
   • Overhead guards are in place to protect the operator against falling objects.
   • Trucks are operated at a safe speed.
   • All loads are kept stable, safely arranged and fit within the rated capacity of the truck.
   • Unsafe and defective trucks are removed from service.

Duties of civil engineers

Civil engineers typically do the following:

• Analyze survey reports, maps, and other data to plan projects
• Consider construction costs, government regulations, potential environmental hazards, and other factors in planning stages and risk analysis
• Compile and submit permit applications to local, state, and federal agencies verifying that projects comply with various regulations
• Perform or oversee soil testing to determine the adequacy and strength of foundations
• Test building materials, such as concrete, asphalt, or steel, for use in particular projects
• Provide cost estimates for materials, equipment, or labor to determine a project's economic feasibility
• Use design software to plan and design transportation systems, hydraulic systems, and structures in line with industry and government standards
• Perform or oversee, surveying operations to establish reference points, grades, and elevations to guide construction
• Present their findings to the public on topics such as bid proposals, environmental impact statements, or property descriptions
• Manage the repair, maintenance, and replacement of public and private infrastructure

Many civil engineers hold supervisory or administrative positions ranging from supervisor of a construction site to city engineer. Others work in design, construction, research, and teaching. Civil engineers work with others on projects and may be assisted by civil engineering technician.

The federal government employs civil engineers to do many of the same things done in private industry, except that the federally employed civil engineers may also inspect projects to be sure that they comply with regulations.

Civil engineers work on complex projects, so they usually specialize in one of several areas.

Construction engineers manage construction projects, ensuring that they are scheduled and built in accordance with the plans and specifications. They are typically responsible for design and safety of temporary structures used during construction.

Geotechnical engineers work to make sure that foundations are solid. They focus on how structures built by civil engineers, such as buildings and tunnels, interact with the earth (including soil and rock). In addition, they design and plan for slopes, retaining walls, and tunnels.

Structural engineers design and assess major projects, such as buildings, bridges, or dams, to ensure their strength and durability.

Transportation engineers plan, design, operate, and maintain everyday systems, such as streets and highways, but they also plan larger projects, such as airports, ports, mass transit systems, and harbors.

EIFFEL TOWER

The Eiffel Tower  is an iron lattice tower located on the Champ de Mars inParis, France. It was named after the engineer Alexandre Gustave Eiffel, whose company designed and built the tower. Erected in 1889 as the entrance arch to the 1889 World Fair, it was initially criticised by some of France's leading artists and intellectuals for its design, but has become both a global cultural icon of France and one of the most recognizable structures in the world. The tower is the tallest structure in paris and the most-visited paid monument in the world; 6.98 million people ascended it in 2011. The tower received its 250 millionth visitor in 2010.

The tower is 324 metres (1,063 ft) tall,  about the same height as an 81-storey building. Its base is square, 125 metres (410 ft) on a side. During its construction, the Eiffel Tower surpassed the Washington Monument to assume the title of the tallest man-made structure in the world, a title it held for 41 years, until the Chrysler Building in New York City was built in 1930. Because of the addition of the aerial atop the Eiffel Tower in 1957, it is now taller than the Chrysler Building by 5.2 metres (17 ft). Not includingbroadcast aerials, it is the second-tallest structure in France, after the Millau Viaduct.

The tower has three levels for visitors, with restaurants on the first and second. The third level observatory's upper platform is 276 m (906 ft) above the ground,  the highest accessible to the public in the European Union. Tickets can be purchased to ascend bystairs or lift (elevator) to the first and second levels. The climb from ground level to the first level is over 300 steps, as is the walk from the first to the second level. Although there are stairs to the third and highest level, these are usually closed to the public and it is generally only accessible by lift.

The design of the Eiffel Tower was originated by Maurice Koechlin and Émile Nouguier, two senior engineers who worked for theCompagnie des Établissements Eiffel, after discussion about a suitable centrepiece for the proposed 1889 Exposition Universelle, aWorld's Fair which would celebrate the centennial of the French Revolution. In May 1884 Koechlin, working at home, made an outline drawing of their scheme, described by him as "a great pylon, consisting of four lattice girders standing apart at the base and coming together at the top, joined together by metal trusses at regular intervals". Initially Eiffel himself showed little enthusiasm, but he did sanction further study of the project, and the two engineers then asked Stephen Sauvestre, the head of company's architectural department, to contribute to the design. Sauvestre added decorative arches to the base, a glass pavilion to the first level, and other embellishments. This enhanced version gained Eiffel's support: he bought the rights to the patent on the design which Koechlin, Nougier, and Sauvestre had taken out, and the design was exhibited at the Exhibition of Decorative Arts in the autumn of 1884 under the company name. On 30 March 1885 Eiffel presented a paper on the project to the Société des Ingénieurs Civils; after discussing the technical problems and emphasising the practical uses of the tower, he finished his talk by saying that the tower would symbolise

Little happened until the beginning of 1886, when Jules Grévy was re-elected as President and Édouard Lockroy was appointed as Minister for Trade. A budget for the Exposition was passed and on 1 May Lockroy announced an alteration to the terms of the open competition which was being held for a centerpiece for the exposition, which effectively made the choice of Eiffel's design a foregone conclusion: all entries had to include a study for a 300 m (980 ft) four-sided metal tower on the Champ de Mars. On 12 May a commission was set up to examine Eiffel's scheme and its rivals and on 12 June it presented its decision, which was that all the proposals except Eiffel's were either impractical or insufficiently worked out. After some debate about the exact site for the tower, a contract was finally signed on 8 January 1887. This was signed by Eiffel acting in his own capacity rather than as the representative of his company, and granted him 1.5 million francs toward the construction costs: less than a quarter of the estimated 6.5 million francs. Eiffel was to receive all income from the commercial exploitation of the tower during the exhibition and for the following twenty years. Eiffel later established a separate company to manage the tower, putting up half the necessary capital himself.

Work on the foundations started on 28 January 1887. Those for the east and south legs were straightforward, each leg resting on four 2 m (6.6 ft) concrete slabs, one for each of the principal girders of each leg but the other two, being closer to the river Seine, were more complicated: each slab needed two piles installed by using compressed-air caissons 15 m (49 ft) long and 6 m (20 ft) in diameter driven to a depth of 22 m (72 ft) to support the concrete slabs, which were 6 m (20 ft) thick. Each of these slabs supported a block built oflimestone each with an inclined top to bear a supporting shoe for the ironwork.

Each shoe was anchored into the stonework by a pair of bolts 10 cm (4 in) in diameter and 7.5 m (25 ft) long. The foundations were complete by 30 June and the erection of the ironwork began. The very visible work on-site was complemented by the enormous amount of exacting preparatory work that was entailed: the drawing office produced 1,700 general drawings and 3,629 detailed drawings of the 18,038 different parts needed. The task of drawing the components was complicated by the complex angles involved in the design and the degree of precision required: the position of rivet holes was specified to within 0.1 mm (0.004 in) and angles worked out to onesecond of arc. The finished components, some already riveted together into sub-assemblies, arrived on horse-drawn carts from the factory in the nearby Parisian suburb of Levallois-Perret and were first bolted together, the bolts being replaced by rivets as construction progressed. No drilling or shaping was done on site: if any part did not fit it was sent back to the factory for alteration. In all there were 18,038 pieces joined by two and a half million rivets.

At first the legs were constructed as cantilevers but about halfway to the first level construction was paused in order to construct a substantial timber scaffold. This caused a renewal of the concerns about the structural soundness of the project, and sensational headlines such as "Eiffel Suicide!" and "Gustave Eiffel has gone mad: he has been confined in an Asylum" appeared in the popular press.At this stage a small "creeper" crane was installed in each leg, designed to move up the tower as construction progressed and making use of the guides for the lifts which were to be fitted in each leg. The critical stage of joining the four legs at the first level was complete by the end of March 1888. Although the metalwork had been prepared with the utmost precision, provision had been made to carry out small adjustments in order to precisely align the legs: hydraulic jacks were fitted to the shoes at the base of each leg, each capable of exerting a force of 800 tonnes, and in addition the legs had been intentionally constructed at a slightly steeper angle than necessary, being supported by sandboxeson the scaffold. Although construction involved 300 on-site employees, only one person died thanks to Eiffel's stringent safety precautions and use of movable stagings, guard-rails, and screens.

Working of total station

1. A total station or TST (total stationtheodolite) is an electronic/optical instrument used in modern surveying and building construction. The total station is an electronic theodolite (transit) integrated with an electronic distance meter (EDM) to read slope distances from the instrument to a particular point.

2. Angle measurement

   Most modern total station instruments measure angles by means of electro-optical scanning of extremely precise digital bar-codes etched on rotating glass cylinders or discs within the instrument. The best quality total stations are capable of measuring angles to 0.5 arc-second. Inexpensive "construction grade" total stations can generally measure angles to 5 or 10 arc-seconds.

3. Distance measurement

   Measurement of distance is accomplished with a modulated microwave or infrared carrier signal, generated by a small solid-state emitter within the instrument's optical path, and reflected by a prism reflector or the object under survey. The modulation pattern in the returning signal is read and interpreted by the computer in the total station. The distance is determined by emitting and receiving multiple frequencies, and determining the integer number of wavelengths to the target for each frequency. Most total stations use purpose-built glass corner cube prism reflectors for the EDM signal. A typical total station can measure distances with an accuracy of about 1.5 millimeters (0.0049 ft) + 2 parts per million over a distance of up to 1,500 meters (4,900 ft).^[2]
   Reflectorless total stations can measure distances to any object that is reasonably light in color, up to a few hundred meters.

4. Coordinate measurement

   Some total stations can measure the coordinates of an unknown point relative to a known coordinate can be determined using the total station as long as a direct line of sight can be established between the two points. Angles and distances are measured from the total station to points under survey, and the coordinates (X, Y, and Z or easting, northing and elevation) of surveyed points relative to the total station position are calculated using trigonometry and triangulation. To determine an absolute location a Total Station requires line of sight observations and must be set up over a known point or with line of sight to 2 or more points with known location.
   For this reason, some total stations also have a Global Navigation Satellite System receiver and do not require a direct line of sight to determine coordinates. However, GNSS measurements may require longer occupation periods and offer relatively poor accuracy in the vertical axis.

5. Data processing

   Some models include internal electronic data storage to record distance, horizontal angle, and vertical angle measured, while other models are equipped to write these measurements to an external data collector, such as a hand-held computer.
   When data is downloaded from a total station onto a computer, application software can be used to compute results and generate a map of the surveyed area. The newest generation of total stations can also show the map on the touch-screen of the instrument immediately after measuring the points.

   Applications

   Total stations are mainly used by land surveyors and civil engineers, either to record features as in topographic surveying or to set out features (such as roads, houses or boundaries). They are also used by archaeologists to record excavations and by police, crime scene investigators, private accident reconstructionists and insurance companies to take measurements of scenes. Meteorologists also use total stations to track weather balloons for determining upper-level winds.

   Mining

   Total stations are the primary survey instrument used in mining surveying.
   A total station is used to record the absolute location of the tunnel walls (stopes), ceilings (backs), and floors as the drifts of an underground mine are driven. The recorded data are then downloaded into a CAD program, and compared to the designed layout of the tunnel.
   The survey party installs control stations at regular intervals. These are small steel plugs installed in pairs in holes drilled into walls or the back. For wall stations, two plugs are installed in opposite walls, forming a line perpendicular to the drift. For back stations, two plugs are installed in the back, forming a line parallel to the drift.
   A set of plugs can be used to locate the total station set up in a drift or tunnel by processing measurements to the plugs by intersection and resection.

   Mechanical and Electrical Construction

   Total stations have become the highest standard for most forms of construction layout.
   It is most often used in the X and Y axis to layout the locations of penetrations out of the underground utilities into the foundation, between floors of a structure, as well as roofing penetrations.
   Because more commercial and industrial construction jobs have become centered around Building Information Modeling (BIM) the coordinates for virtually every pipe, conduit, duct and hanger support are available with digital precision. The application of communicating a virtual model to a tangible construction potentially eliminates labor costs related to moving poorly measured systems, as well as time spent laying out these systems in the midst of a full blown construction job in progress.

Taj mahal (INDIA)

The Taj  Mahal Commissioned in 1632 by the Mughal emperor Shah Jahan to house the worldly remains of his third wife, Mumtaz Mahal, the Taj Mahal stands on the southern bank of the Yamuna River. The mausoleum is widely recognized as "the jewel of Muslim art in India" and remains as one of the world’s most celebrated structures and a symbol of India’s rich history.

Regarded by many as the best example of the Mughal architecture, it is a perfect blend combining elements from Islamic,Persian, Ottoman Turkish as well as Indian architectural styles.

The famed mausoleum complex of white domed marble of the Taj Mahal, it actually is an integrated complex of many structures. The construction began around 1632 and was completed around in 22 years, in 1653, employing around 20,000 artisans and craftsmen throughout the empire. The construction was entrusted to a board of architects, the chief architect probably beingUstad Ahmad Lahauri, an Indian of Persian descent.

In 1631, Shah Jahan, emperor during the Mughal empire's period of greatest prosperity, was grief-stricken when his third wife, Mumtaz Mahal, a Persian princess, died during the birth of their 14th child, Gauhara Begum.^[16] Construction of the Taj Mahal began in 1632.^[17] The court chronicles of Shah Jahan's grief illustrate the love story traditionally held as an inspiration for Taj Mahal.^[18][19] The principal mausoleum was completed in 1648 and the surrounding buildings and garden were finished about five years later. The Emperor himself described the Taj  in these words  

Should guilty seek asylum here,
Like one pardoned, he becomes free from sin.
Should a sinner make his way to this mansion,
All his past sins are to be washed away.
The sight of this mansion creates sorrowing sighs;
And the sun and the moon shed tears from their eyes.
In this world this edifice has been made;
To display thereby the creator's glory.
 

Outlying buildings

The Taj Mahal complex is bounded on three sides by crenellated red sandstone walls, with the river-facing side left open. Outside the walls are several additional mausoleums, including those of Shah Jahan's other wives, and a larger tomb for Mumtaz's favourite servant.

The main gateway (darwaza) is a monumental structure built primarily of marble which is reminiscent of Mughal architecture of earlier emperors. Its archways mirror the shape of tomb's archways, and its pishtaq arches incorporate the calligraphy that decorates the tomb. The vaulted ceilings and walls have elaborate geometric designs, like those found in the other sandstone buildings of the complex.

At the far end of the complex, there are two grand red sandstone buildings that face the sides of the tomb. Their backs parallel the western and eastern walls, and the two buildings are precise mirror images of each other. The western building is a mosque and the other is the jawab(answer), whose primary purpose was architectural balance, although it may have been used as a guesthouse. The distinctions between these two buildings include the lack of mihrab (a niche in a mosque's wall facing Mecca) in the jawab and that the floors of jawab have a geometric design, while the mosque floor was laid with outlines of 569 prayer rugs in black marble. The mosque's basic design of a long hall surmounted by three domes is similar to others built by Shah Jahan, particularly to his Masjid-Jahan Numa, or Jama Masjid, Delhi. The Mughal mosques of this period divide the sanctuaryhall into three areas, with a main sanctuary and slightly smaller sanctuaries on either side. At the Taj Mahal, each sanctuary opens onto an enormous vaulting dome. These outlying buildings were completed in 1643.

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Construction

According to the legend, Shah Jahan decreed that anyone could keep the bricks taken from the scaffold, and thus it was dismantled by peasants overnight. A fifteen kilometer (9.3 mi) tamped-earth ramp was built to transport marble and materials to the construction site and teams of twenty or thirty oxen pulled the blocks on specially constructed wagons.An elaborate post-and-beam pulley system was used to raise the blocks into desired position. Water was drawn from the river by a series of purs, an animal-powered rope and bucket mechanism, into a large storage tank and raised to a large distribution tank. It was passed into three subsidiary tanks, from which it was piped to the complex.The Taj Mahal is built on a parcel of land to the south of the walled city of Agra. Shah Jahan presented Maharajah Jai Singh with a large palace in the center of Agra in exchange for the land. An area of roughly three acres was excavated, filled with dirt to reduce seepage, and leveled at 50 metres (160 ft) above riverbank. In the tomb area, wells were dug and filled with stone and rubble to form the footings of the tomb. Instead of lashed bamboo, workmen constructed a colossal brick scaffold that mirrored the tomb. The scaffold was so enormous that foremen estimated it would take years to dismantle.

The plinth and tomb took roughly 12 years to complete. The remaining parts of the complex took an additional 10 years and were completed in order of minarets, mosque and jawab, and gateway. Since the complex was built in stages, discrepancies exist in completion dates due to differing opinions on "completion". For example, the mausoleum itself was essentially complete by 1643, but work continued on the rest of the complex. Estimates of the cost of construction vary due to difficulties in estimating costs across time. The total cost has been estimated to be about 32 million Rupees at that time.

The construction of the Taj Mahal was entrusted to a board of architects under imperial supervision, including Abd ul-Karim Ma'mur Khan, Makramat Khan, and Ustad Ahmad Lahauri. Lahauri  is generally considered to be the principal designer.The Taj Mahal was constructed using materials from all over India and Asia and over 1,000 elephants were used to transport building materials. The translucent white marble was brought from Makrana, Rajasthan, the jasper from Punjab, jade and crystal from China. The turquoise was fromTibet and the Lapis lazuli from Afghanistan, while the sapphire came from Sri Lanka and the carnelian from Arabia. In all, twenty eight types of precious and semi-precious stones were inlaid into the white marble.

A labour force of twenty thousand workers was recruited across northern India. Sculptors from Bukhara, calligraphers from Syria and Persia, in-layers from southern India, stone cutters from Baluchistan, a specialist in building turrets, another who carved only marble flowers were part of the thirty-seven men who formed the creative unit. Some of the builders involved in construction of Taj Mahal are:

• Ismail Afandi (a.k.a. Ismail Khan) - had previously worked for the Ottoman Sultan and is regarded by some as the designer of the main dome.
• Ustad Isa, born either in Shiraz, Ottoman Empire or Agra – credited with a key role in the architectural design and main dome.
• 'Puru' from Benarus, Persia – has been mentioned as a supervising architect.
• Qazim Khan, a native of Lahore – cast the solid gold finial.
• Chiranjilal, a lapidary from Delhi – the chief sculptor and mosaicist.
• Amanat Khan from Shiraz, Iran – the chief calligrapher.
• Muhammad Hanif – a supervisor of masons.
• Mir Abdul Karim and Mukkarimat Khan of Shiraz – hand led finances and management of daily production.

History

Soon after the Taj Mahal's completion, Shah Jahan was deposed by his son Aurangzeb and put under house arrest at nearby Agra Fort. Upon Shah Jahan's death, Aurangzeb buried him in the mausoleum next to his wife.Abdul Hamid Lahauri, the author of the Badshahnama, the official history of Shah Jahan's reign, calls Taj Mahal rauza-i munawwara, which means the illumined or illustrious tomb.

In the 18th century, the Jat rulers of Bharatpur invaded Agra and attacked the Taj Mahal, the two chandeliers, one of agate and another of silver, which were hung over the main cenotaph, were taken away by them, also the gold and silver screen. According to Mughal historian Kanbo, the 15-foot high finial at the top of the main dome of the Taj Mahal was covered with a gold shield and this was also removed during the Jat despoliation.

By the late 19th century, parts of the buildings had fallen badly into disrepair. During the time of the Indian rebellion of 1857, the Taj Mahal was defaced by British soldiers and government officials, who chiselled out precious stones and lapis lazuli from its walls. At the end of the 19th century, British viceroy Lord Curzon ordered a sweeping restoration project, which was completed in 1908. He also commissioned the large lamp in the interior chamber, modelled after one in a Cairo mosque. During this time the garden was remodelled with British-style lawns that are still in place today.

Threats

More recent threats have come from environmental pollution on the banks of Yamuna River including acid rain  due to the Mathura Oil Refinery, which was opposed by Supreme Court of India directives.The pollution has been turning the Taj Mahal yellow. To help control the pollution, the Indian government has set up the Taj Trapezium Zone (TTZ), a 10,400-square-kilometre (4,000 sq mi) area around the monument where strict emissions standards are in place.^[54]In 1942, the government erected a scaffolding in anticipation of an air attack by Japanese Air Force. During the India-Pakistan warsof 1965 and 1971, scaffoldings were again erected to mislead bomber pilots.

Concerns for the tomb's structural integrity have recently been raised because of a decline in the groundwater level in the Yamuna riverbasin which is falling at a rate of around 5 feet a year. In 2010, cracks appeared in parts of the tomb, and the minarets which surround the monument were showing signs of tilting, as the wooden foundation of the tomb may be rotting due to lack of water. In 2011 it was reported that some predictions indicated that the tomb could collapse within 5 years.

Tourism

The small town to the south of the Taj, known as Taj Ganji or Mumtazabad, was originally constructed with caravanserais, bazaars and markets to serve the needs of visitors and workmen. Lists of recommended travel destinations often feature the Taj Mahal, which also appears in several listings of seven wonders of the modern world, including the recently announced New Seven Wonders of the World, a recent poll  with 100 million votes.The Taj Mahal attracts a large number of tourists. UNESCO documented more than 2 million visitors in 2001, including more than 200,000 from overseas.A two tier pricing system is in place, with a significantly lower entrance fee for Indian citizens and a more expensive one for foreigners. Most tourists visit in the cooler months of October, November and February. Polluting traffic is not allowed near the complex and tourists must either walk from parking lots or catch an electric bus. The Khawasspuras (northern courtyards) are currently being restored for use as a new visitor center.

The grounds are open from 06:00 to 19:00 weekdays, except for Friday when the complex is open for prayers at the mosque between 12:00 and 14:00. The complex is open for night viewing on the day of the full moon and two days before and after, excluding Fridays and the month of Ramadan. For security reasons only five items—water in transparent bottles, small video cameras, still cameras, mobile phones and small ladies' purses—are allowed inside the Taj Mahal.