Modelling and Optimal Control of Tower Crane Motions - Case Study Example

Bid Proposal Student’s Name Course November 2012 Introduction Experience Design and calculation Cost breakdown Conclusion Introduction This document is response to your invitation to tender to design, manufacture and delivery the 100 kits. Each kit is expected to have the follwing among other things 1. A bridge to span 8m with a further 1.5m at each end as anchor locations which can withstand a 5 tonne central load. 2. A pair of towers each 4m high to act as supports for a cable winch system to carry goods and personnel over a gap of up to 80m. The expected payload will be up to 250kg. 3. A structural frame for a field clinic. This will have a floor 4m x 4m and be 2.5m high. The kit is expected to fit in a two ton truck that has 6m by 2m bed. Company profile Established by John as Johns Corporation, Johns corporation started operations as a light mechanical engineering company, in 1936. Its head office was in Sydney, Australia, from where it performed the functions of delivering light forklifts, cranes and involved in the construction industry. The firm capitalized on the design and making of rescue equipment since then. The vertical development enabled the company to acquire certification to venture into the business of making rescue equipment. Our company is one of the companies that is involved in construction of various portable archtectural and engineering structure. We have partnered and delivered various bid billed projects in areas of engineering, most notably the construction of portable structures for rescue missions in the former yugoslavia, Tsunami in Indonesia and Japan, Iran eartquake. We were involved in equipments that were used in New York and New Jersey. We have successfully managed this project thus we have a quality and experienced team. However, we have various changes expected in our organisation which includes the partnering with an archtectural firm who will be responsible for making our all designs. The archtecture in question has a wealthy experience in drawing and designing of buildings because he has worked with various multinational archtec firms. He will come to our organization with 30 years design experience attained in those organizations. After employing multiple strategies to limit expenditures, enhance revenues, and reverse substantial losses, the company immediately adopted cost-cutting measures and six-sigma to realize quality management, which is vital for quality products. Generally, the company has a reputation of proper organization and the earning of better revenues. The company’s effectiveness in winning over market assets, and concerns for safety; delight in providing services; smooth compliance with labor laws; and the worldwide expansion guaranteed Johns Corporation the needed competitive edge. These qualities elevated the company to become one of the largest and reputable rescue equiment manfucturere companies, over the past seven decades. In spite of the safety and economic problems that the industry faces, and the persistent challenge of working in a deregulated economy, its nerve center at Sydney. Modelling and Calculations Within a period of twenty days, we will be able to design the project into totality without leaving anything out. The equipments has been adequately designed for safe operations of pair of towers, a bridge and field. However, most often the pair of towers usage required trained handlers to handle during. Potential health, safety and other costs that may befall you don’t comply with the regulations or recommended safety procedures. We will provide comprehensive safety training to operators irrespective of the frequency of their operation of these equipment. Some of the key compliance points we will provide are, classroom and hands-on equipment training, experienced trainers, all pair of towers and bridge operators should be certified, the training will be site and equipment specific, reevaluation of all operators every 3 years, provision of refresher training in the event of near miss or unsafe operation, evaluation, training sessions are documented. Pair of towers- The pair of towers will be designed in such a way that overhead and side clearances are sufficient to carry out safe operations and to accommodate loads that are being moved. Pair of towers will be 4m high to help in carrying people over a distance of 80m. The structure tower will be as follows; The pairs of towers that are designed will mount to pulleys in conjunction with system designed above. When being operated the leg offers stability so that it does no fail to perform functions properly. The system will have a rope of up 80m for rescue mission it will have the ability lift load worth 250kg. A pair of towers that will support cable which system to carry people and goods over a gap of 80m and up to load capacity of 250kg at ago. In brief, the pair of towers will consists columns are placed across each side. The polipastos will required during the usage to make sure the two towers are above the ground. This will resemble the pulleys system when carrying goods as shown below; The diagram above shows how the pair of towers could be used during emergency cases. It has been designed in such a manner to allow the rescue team move the rescued along the tower line because of the confusion associated with the emergency cases. The mechanism of the tower is situated at the pulleys which rotate when pulled. It is operated by controlling and moderating the stretcher which is adjustable. We will design it efficiently so that it can achieve accurate results. This will require us to have dowels and holes in the drums which are identical to each other. The drum will have a motor which will be used to drive the pulley. The toggle will be used in controlling the ropes of the tower during the period of evacuation. The pair of tower will have the following:- an engine, pressure boost, hydraulic oil level, filter, gear box and engine coolant. The pair tower will be expected to a stainless steel wire which will be not less than 80m for the safety during the rescue mission worldwide. This will ensure the safety of the personnel who are rescued. The pair of towers will be having 320kg that is 160kg when single this will ensure that they are able to carry weight of about 250kg. It is designed in a manner that it allows rescue load not exceed the weight of the towers. It will carry a single load of 250kg at ago at the time of 30s that is 500kg/m. this can be used to rescue individuals stuck in building on fire, underground rescue missions, people stuck in flooded area and many other places which are confined and individual’s needs to rescue. The rope that will be used will be assumed to stretchable and to carry on this pair of towers should be proportional to elasticity of the rope. The force to be applied is determined as follows; MAXIMUM force=mg[1+ m is the weight to be lifted by the pair of towers, F is the fall factor of the rope to be used and s is the percentage stretch. In the pair of towers designed is assumed to be have 3% stretch and fall factor of 0.75 Maximum force=250x 9.81[1+ =12.26kN Since the maximum force is 12.26kN the maximum possible value before the cable breaks can be arrived as The time to move the crate up a distance starting from rest can be found from Setting = 0 and solving for , we find Our equation applies only for (the create reaches the window after it leaves the ground). Taking the positive root and substituting numerical values. 4.88 s This is the minimum possible to haul the crate up without breaking the rope. No load should pass over any worker, the loads of the pair of towers should not exceed the maximum rated capacity, and the loads should be handled as per the height, weight and capacity of the pair of towers. A pair of towers operator should have clear view of the path or else a signal handler trained in signaling be employed to handle the pair of towers traffic at the workplace. Loads should be carried as close to the ground, and loads that run the risk of tipping or falling over should be adequately secured. We will build it to have higher winch performance on the luff and the hoist section, with modernized hydraulics as opposed to the diesel hydraulics. The entire structure has to be modified to accommodate extra winches, extra modular booms and two-piece machinery deck. A fly jib can also be used if wanted by the client. The machinery deck can be split into two for ease of transportation by removing joint pins, facilitating new needs for construction transportation. Multiple variable displacement hydraulic pumps are used to operate the luff, slew, hoist and climbing components of the tower. The winches are fitted with parallel grooved drums and a splash lubricated, oil immersed disc brake (to minimize danger and optimize lubrication). Also for safety purposes, the luff drum is fitted with a pawl and ratchet system that engages as soon as the tower is shut down (Favelle Favco, 2003: 5). These winches have a double fall hook but the option of a single fall hook fly winch is also available (Favelle Favco, 2003: 5). The rate of movement on an pair of towers will be controlled by hand with the help of extraneous booms. The slew rate has to be calculated in a number of ways as wind, vibration and weight all contribute to the slew rate. The luffing jib can also be moved horizontally to work in confined spaces without having to dismantle the crane. Field clinic- Aftergoing through the invitation to tender for the construction of evacuation kit where a field clinic is required measuring 4m by 4m and 2.5m high I have come up with the following structure as the floor layout. The structure has frames which will allow a patition during evacuation mission. The frame will consist of steel rods which will have places for bolts. At the joints bolts will be used to connect various parts of the frame structure. The structure will use canvous as the roof and walls however our mandate is to design and construct a standardized frame which is portable and can be used for the intended purpose. The design of the ground and walls structure will only include features that involve steel rods that can be disjointed when the mission is over. Floor Layout Bridge designing- The bridge is expected to span 8 meters long with a further 1.5 meters at the end of each anchor locations. The bridge is having load allowance of 5 tonne at the central. It will have steel girders with 100% compatibility. The materials that can be used in the construction of these bridge include:- precast in forcing steel, structural bolts, anchor roads, piling, concrete, bridgerail, handrail The above diagram shows the spacing design and bridge structure that will used however they will not be fixed. The reinforcement adopted are strong enough to withstand the weight of 5 tonne at the centre during operation. The bridge has two joints which makes it portable and can be used. The bridge will have a load capacity of 2 tonne but this will depend on the ground of rescue. Soft grounds will require less load due to the fact that it not safe to carry large load. The framework of the shall be made at a temperature of +25o C however will be able to at temperature of +38o C to -8o C. This temperatures will provide a bearing in which environment the bridge will be used without expansion or contraction. Contraction and expansion are likely to change the strength of the bridge. The bridge will have a continuous steel girder which will be joint at the centre when in use. The base will be designed in a manner that it will be at the centre with stiffeners which will provide the bearing. The voids should have enough space to anchor the bridge. The length changes of the bridge are accommodated in the temperatures mentioned in this proposal. The length mentioned in this is measured at the bottom of the bridge at a room temperature of 250C. We will provide abutment and piers for the bridge to allow the bridge be used in areas where it is very cold upto -80C. The longitudinal of the bridge will have a minimum of 1%. However it is possible for it to reduce to 0.5%. The main reason for this is because the bridge can be used in areas where there is a lot of water. The proposed bridge being portable will have a structure that supports tiny walls piers and abutment. It will have a vertical clearance of 5metres. The critical vertical clearance should be 3metres. However the minimum vertical clearance is set to be 3.2metres. It will have skew angles of 11031’ and a side walk which has a median of 3%. The bridge will be 8m long and have 1.5m at each end as anchors. It will have a joint at the centre which will be disconnected in case of transportation. It will be 1.5m wide with 1 % grade, a Manning’s roughness coefficient (n) of 0.015; it will be designed to have a cross section slope of 0.2% while the runoff coefficient will be assumed to be 0.9. Will assume 10 year frequency and design intensity of 2.1 per minute. The bridge will require a concentration of This is concentation at anchors without tilting while other parts of bridge have no any load. The bridge has the capacity to help ferry loads at a flow of Therefore the bridge will have fully load capacity for a total of continuous without stress. The inlet efficient of the rescue brdge will be computed as follows The bridge will be able to accept the speed of 1.3m/s while using it. This is arrived as; . A Pair of Towers Maintenance and Modification- There should be periodic maintenance and repairs of a pair of towers. Any modifications such as addition to the load capacity should be carried with written sanction from the our qualified engineer. There should be regular inspection, testing and maintenance of pair of towers. The instructions should be written, and the frequency of the inspections, testing and maintenance should be based on the amount of work done by these pair of towers. The instructions in place should at least match the minimum requirements has lain out by the manufacturer of the equipment. Proper records of all inspection, testing and maintenance carried out on each pair of towers should be maintained at the workplace. In order to make the equipments safe it should be washed when used especially in dirty areas. The winches that will be designed in this pair of towers will not complex to clean since they will allow the cables to be unrolled so that for cleaning can be easy. The winches will not be of a large length especially larger than the rope that will be used. This means we will use capstan winches which can be wrapped to enable the clumps to rotate and roll in number of times. The main purpose of capstan winches is to enable the rescuers manage to use a length that is the size of the load they are carrying. Cost Breakdown Cost is an important element that has to be taken into account when one is either building or designing with an aim of attaining a high safety standards. Description Quantity Unit Bid Price Total Value A Bridge 1 100 7612.50 761,250 A Pair of Towers 1 100 8,5000 850,000 Field clinic 1 100 4,727 472,700 Total cost 2,083,950 Cost estimate for mobile clinic Description Price per Unit ($) Number of Units Total Cost per Unit Poles 60 12 720 Ropes 20 5 100 Frame Retadant 1,500 1 1,500 Sun Forge 1,000 1 1,000 Sord 400 1 400 3,720 Storage and Shipping Cost (10%) 372 4,092 Freight, and Insurance Cost (5%) 205 4,297 GTS Tax @ 10% 430 Total cost 4,727 The cost per bridge Details Cost per Unit Number of Units Total Cost Steel pilling 14 by 89 40 50 2,000 Steel pilling 24 pipe inch 95 4 380 Drilled shaft 4 ft 300 1 300 Bearing material 4,000 1 4,000 Plate girders 1.5 15 22.50 Box girders 2 15 30 Solid flat slab 1 130 130 Single pier 250 3 750 7,612.50 Conclusion Our bid is based on the market rate and the product will be delivered within a period of 21 days without delay. We have delivered similar products to various organizatons. We undertake full responsibilities for delays and failure of the item. If the item fails we will repair it or replace it within a period of one year. If given the contract to supply the kit we will be happy and deliver within a short of period. References Favelle F, (2003). M440D Construction Tower Crane Specifications. Getting, J. (2008). Tower Crane Accidents: Causes, Concern and Correct Procedures. MichiganSafety Conference. Golafshani, Ali. R. (1999). Modelling and Optimal Control of Tower Crane Motions. University of Waterloo. Read More