الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Construction projects are divided to so many categories such as Silos, infrastructure works, building works, industrial factories , tunnels, bridges, towers , marine works, oil and gas
works , etc. the common thing between all of these projects are Lifting and handling.
We cannot execute the above mentioned scope without the lifting and handling phase.
Lifting can classified as a kike off activity in any time schedule for any project. What ever small, medium or large projects, there are so many projects delayed due to shortage and fail
. to execute the anticipated lifting phase for lifting materials and moving materials.
This research presents the results of a survey undertaken to determine and evaluate the most severe and most frequent factors causing delaying and stopping for projects.
The results of the study proved that construction projects need cranes for lifting, handling materials and equipments and we can’t save time and money for big area projects and high buildings without cranes.
This research validates that tower crane is very important for projects especially big, wide and high constructions. The tower crane is a modern form of balance crane. Tower cranes often give the best combination of height and lifting capacity and are used in the construction of tall buildings. Tower Cranes are cranes comprising a vertical tower with ajib located at the top of the tower. Each crane have log book must updated daily and sign by the operator. Tower crane have many types according to tower type and jib type. Tower crane must be designed by a competent person. Tower crane stability depends on stabilizing and overturning moments, counterweights, arrangement of the central ballast block, crane ties, wind conditions and loads of the cranes. Tower crane erection details will vary with different machines. Tower crane have four basic types of mounting configurations.
The erecting and dismantling of a tower crane is construction work. There are a number of activities associated with this work that are high risk construction activities such as a person could fall at least two meters in construction work, crane collapse, falls from heights and Falling objects. We can minimize the risk of injury from crane collapse by making pre¬erection inspections and tests, climbing tower cranes-ways, precautions for certain tower cranes with moving counterweights. We can minimize risk of injury from falling from a height by systems such as edge protection systems, travel restraint systems, fall-arrest harness systems. We can prevent or minimize risk of injury from falling objects by exclusion zones, too11anyards, mesh screens, scheduling of work and restraining systems. Tower crane was inspected by a competent person daily, weekly, monthly, and yearly and every 10 year.
Tower crane cost factors are initial cost, training cost, running cost and maintenance cost. Every tower crane must be equipped with several properly installed and set limit switches to prevent crane overload such trolley limit switch, hook height Limit Switch, rail travel limit switch, lufting jib limit switch, hoist drum stop limit switches and jib pendant tension overload switch. A tower crane must weathervane if lift unattended. An anemometer (wind gauge) should be fixed on each tower crane, in an appropriate location, to provide an accurate wind speed reading. Camera device can be attached with tower crane to help the operator to seeing the load from height. Anti-collision control can be attached with tower crane.
There is some cranes have a saddle jib such GG tower crane. This large saddle jib allows the cranes to have a jib up to 150 m long on each side, giving a working diameter on the largest model of 300 m.