Dr. Ahmed Hussien Elyamany 2017 Questions

Transcription

1 Questions Question 1 (25 Marks): Select the best answer from the available choices for each of the following: 1. Cranes may be used for 2. cranes consist of a carrier and superstructure equipped with a boom and hook 3. The major factor controlling the load that may be safely lifted by a crane is 4. Factors influencing a crane s safe lifting capacity include 5. Factors influencing a crane s safe lifting capacity include 6. Factors influencing a crane s safe lifting capacity include 7. Tipping load is the load that cause the crane to 8. Load capacity chart give 9. For safe loading, load-handling devices are considered part of 10. Very heavy loads are usually lifted using 11. Use of extra. can boost the maximum crane capacity 12. Crane having a boom hinged near the base of a fixed mast is known 13. A crane with a Latticework Boom mounted on crawlers provide 14. A crane with Latticework Boom mounted on crawlers is the best choice to lift a load of 15. The main advantage of is moving around site and perform each lift with little setup crane is capable of traveling with a load. 17. is the part of crane that make it stable 18. The main disadvantage of. is that they are very heavy must be disassembled and moved by trucks to its next location 20. are able to travel on highways, eliminating the need to be moved by trucks to its next location 21. Wheel-mounted cranes may have the following parts except 22. have a single-engine machine and a short telescopic boom and outriggers can travel at speed on public roads, and on rough terrain at the job site using allwheel steering have 2-9 axles and are designed for lifting loads up to 1200 tons has a telescopic boom consists of a number of tubes fitted one inside the other often used for short term construction projects and rescue jobs Is only used for loading/unloading the truck are used in areas that are difficult to reach by conventional cranes has a hoist with trolley that runs horizontally along rails of small moveable frame has a hoist with trolley that runs horizontally along rails on two fixed beams on two side-walls often mounted along the side walls in the assembly area of factory located on ships and used for loading/unloading 33.. has two attached frames and 4 wheels and could be used in moving precast elements within precast factory. 1

2 34.. usually, fixed to the ground and sometimes attached to the sides of structures provide height and lifting capacity and are used in the construction of high-rise buildings. 36. The followings are parts of a tower crane except 37.. could be fixed or mobile carries a counterweight, usually of concrete blocks is the person helping crane operator in moving loads 40. Crane operator and signaler always use.. in inter-communication. 41. The rigger is responsible for the followings except 42. A tower crane is usually assembled by 43. Tower cranes have the following boom shapes except 44. The majority of tower cranes have. 45. Tower cranes with operate in areas of restricted horizontal clearance. 46. Tower cranes with can be operated in horizontal or luffed position. 47. Tower cranes with are able to reposition their hinged jibs to convert excess hook reach into added hook height. 48. Tower crane may be mounted on the following except cranes are supported by completed building floors 50. Tower crane capacity depends on the following except 51. The capacity of tower crane increased as 52. A crane with.. could be used in concrete pouring. 53. A crane with.. could be used in moving pipes 54. A crane with.. could be used in pile driving 55. A crane with.. could be used in picking metals 56. A crane with.. could be used in excavation 57. A crane with.. could be used in demolition work. 58. A crane with.. could be used in pile excavation. 59. A crane with.. could be used in lifting reinforcement steel 60. distance between crane and 50KV electricity line should not exceed 61. Crane accidents usually occur when 62.. should be used when there is danger caused by swinging load 63. Safe crane capacity is reduced by 50% when the crane is out of level by are economical for making a limited number of lifts in a short period of time with attachment can perform different types of works 66. Most of the time mobile cranes are move slowly and must travel on a level stable surface. 68. The maximum unsupported tower crane height is 69. To reach higher, tower crane may be attached to 70. Erecting. requires using mobile cranes. 71. Tower crane pieces are typically hauled to the job site by 72. Using tower cranes is safer and more efficient than moving with load m high tower crane is best fixed to 2

3 m high tower crane is best fixed to m high tower crane is best fixed to 76. After tower crane is dismantled, the concrete base should 77. The area covered by a tower crane depend on 78. The area covered by a tower crane depend on the following except 79. To get adequate coverage using tower crane 80. It is more economical to use tower crane with capacity to lift % of the load on hand every day. 81. If 75% of project loads range between 1-5 tons and 25% of loads range between tons, it is most economical to 82. should select locations, capacities, heights, and numbers of tower cranes. 83. Number of tower cranes in one project depend on 84. Tower cranes are usually leased 85. For a company specialized in building skyscrapers, it is more economical to. tower cranes. 86. Unloading a truck immediately by a tower crane, prevents the followings except Cost incurred by lifting must be estimated and included in the project budget at the time of 88. Largest variable time in the cycle time of tower crane is time of 89. Preparing and rigging the load are tasks of 90. Hoisting the load using a tower crane is the task of. 91. Unloading the load using a tower crane is the task of. 92. Selected a method for placing concrete must take into account the following except. 93. Tower cranes are typically used when operating space is. 94. Pouring concrete using a crane with bucket is an economical solution in the following cases except Pouring concrete using a pump is an economical solution in the following cases except The amount of pressure that has to be developed by the pump to place the concrete depend on the following except. 97. The most economical method to pour 130 m3 concrete for a slab with an area 25x25m in 12th floor is. 98. The most economical method to pour 30 m3 concrete for walls and columns of 12th floor is. 99. The most economical method to pour 120 m3 concrete for a 100m long and 4m height wall is The most economical method to pour 120 m3 concrete with 2cm slump for a 25x25m slabon-grade is has a unit weight less than 120 lb/cu ft 102. The process of proportioning cement, water, aggregates, and additives prior to mixing concrete is called significantly increased resistance to freezing and thawing should not be used for reinforced concrete where the steel will be in contact with the concrete. 3

4 105. The process of providing the required water and maintaining a favorable temperature for a period of time after placing concrete is called 106. If prestressed beam were to be lifted at the top center, it will result in 107. Aggregate weight in a concrete mix = 500 kg, sand weight = 300 kg, water weight = 80 kg, cement weight = 160 kg. calculate the weight of water required for 5 bags of cement of 50 kg each systems generally cost more than other systems, and require near-continual maintenance Is a dewatering system that keeps water inside the soil provides both a water cutoff and a structural cofferdam wheelbarrows, buggies, chutes, conveyors, pumps, buckets, and trucks are equipment that can be used in is used to permit early removal of forms and in cold-weather concreting Unit weights of heavy weight concrete may range from 114. Placing the plastic concrete into forms at site and allowing it to harden is called decrease setting time and increase the early strength of concrete is concrete to which an initial compression load has been applied is concrete used on inclined surfaces is a structure used to excavate below water level, where the excavation is performed from within that structure used to delay the setting of concrete when pumping concrete over long distances Concrete in truck mixers should be discharged within may be used for plain concrete, but with compressive strengths 10 20% lower than normal Standard truck mixer capacity ranges from is concrete that has been cast into the desired shape prior to placement in a structure often selects the dewatering method and is responsible for its design and operation Is a system used to accelerate the consolidation of the soil under structures 4

5 Question 2 (10 marks): ABC Construction is a company constructing an office building. Building description Building has 30 floors. The average area of each floor is 25x25 m with area 800 m 2 /floor and floor height of 3.5 m. Average height of concrete column is 3.2 m above the top surface of floor slab. Concrete The average quantity of concrete needed for each floor slab is 200 m 3, while 50 m 3 of concrete is needed for walls and columns of each floor. Normal weight concrete with unit weight 2.5 ton/m 3 is used for slabs and columns. According to specs ready mix concrete is to be used. Ready mix concrete will be transported to project site using truck-mixers with capacity of 5 m 3 each, arriving to site at a rate of 50 m 3 /hr. A tower crane with concrete bucket and a pump truck are available for placing concrete. Pump Truck Pump truck with 60 m boom length is used to pump concrete. The vertical reach of the pump boom is 42 m and the rest 18 m of boom length is needed to cover the pouring surface. The pump truck maximum rate of concrete pumping is 50 m 3 /hr. Pump truck renting include 220 L.E/day for mobilization and basic setting, 8 L.E/m 3 of pumped concrete, and 190 L.E/day for the operator and helper. Assume 8 working hour per working day and 50 min per working hour. Tower crane A Liebherr tower crane with a concrete base is available for lease. The crane capacity is verified for lifting minimum load of 4 tons with radius of 28 m and maximum load of 18 tons with radius of 12 m. Available is a 1.8 m 3 concrete bucket for concrete pouring. The tower crane has an average hoisting speed of 28 m/min. the rest of the cycle for pouring concrete using the concrete bucket is about 2.9 min. It is required to: 1) Calculate the highest floor reached by the pump truck for concrete placing. 2) Calculate the cost of pouring 1 m 3 of concrete in walls and columns of 10 th floor using pump truck. 3) Calculate the duration of pumping concrete to 10 th floor slab. 4) Calculate the maximum radius reached by the concrete bucket when filled with concrete. 5) Calculate the production rate (PR) of pouring concrete in walls and columns of 10 th floor using concrete bucket. 6) Calculate the cost of pouring 1 m 3 of concrete using PR calculated in part (5). 7) Based on parts (2) and (6), which pouring method is most economic for 10 th floor. 8) Calculate the production rate of pouring concrete using concrete bucket for 22 th floor slab. 9) Calculate the cost of placing 1 m3 of concrete using PR calculated in part (8). 10) Calculate number of truck mixers should arrive at site when using concrete bucket for pouring 10 th floor walls and columns so that no truck mixer is idle. 5

6 Question 3 (5 marks): For the following tasks, select the most suitable crane and the most suitable attachment. Task Most suitable crane number 1) Lifting 10 sacks of cement (50 kg/sack) from the ground to the 2 th floor of a building. 2) Lifting 10 pallets (200 pieces/pallet and 0.8 ton/pallet) of cement bricks from trucks to each floor from 1 st to 2 th 3) Lifting 1 unit of air conditioning (10 ton each) to the top of 20 th floor 4) Placing concrete in columns of the 22 th floor 5) Inserting sheet piles along the perimeter of building foundation 6) Moving a 2 ton precast beam from manufacturing area to storage area 7) Lifting 1.5 ton precast beam to the top of a frame 5 m high. Available cranes are; Crane 1 Crane 2 Crane 3 Crane 4 Crane 5 Crane 6 Crane 7 Crane 8 Crane 9 Crane 10 Most suitable attachment number Wheel-mounted crane with 45 m long telescoping boom, 6 axles, and 75 ton lifting capacity. Mobile tower crane with 51 m long articulated jib, and 3.3 ton lifting capacity. Wheel-mounted crane with 53 m long latticework boom, and 190 ton lifting capacity. Truck-mounted crane with articulated boom and 2.6 ton lifting capacity. Crawler-mounted crane with 111 m long Latticework boom, and 391 ton lifting capacity. Straddle crane with 3 ton lifting capacity. Rough Terrain crane with 8 m long telescoping boom, 1 control station, and 1 ton lifting capacity. Tower crane with fixed base and 68 m long Horizontal jib, and 4 ton lifting capacity. Derrick Crane with 1 m long boom and 200 kg lifting capacity Tower crane with climbing base and 33 m long Luffing boom, and 3.9 ton lifting capacity. Available attachments are; Attachment 1 Attachment 2 Attachment 3 Attachment 4 Attachment 5 Attachment 6 Attachment 7 Attachment 8 Attachment 9 Attachment 10 Skips Loading Platform drop hammer Concrete bucket (capacity of 1m 3 ) Grapples Basket sling Clam shell bucket Single chain sling wrecking ball Auger 6