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A representative from the Construction Unit will contact you accordingly. Stakeout Manual. Was this page helpful? Outline of site management after contract signature 31 The layout is drafted at different stages because it is impossible to reflect schemes showing moving construction machinery and working teams, the placement of lifting equipment, sites for material storage, etc.
Construction site layout is usually set out at a scale of or An example of a construction site layout for the erection of a frame is given in Figure 3.
Figure 3. Outline of site management after contract signature 35 The symbols used in the construction site layout are in Appendix 1 3. If a certain task can, technologically and from a management point of view, be initiated before completion of the directly preceding task, then the necessary readiness extent in a chronologically calculated chart on which moment of time is event of previous work must be identified in the chart.
The greatest advantage or freedom for the project manager in further construction time scheduling is available by this type of flow of work, with the beginning of all tasks in the network chart coming at the earliest possible time, and the possibility of completion at the latest, compared to other works. That is the best way to make use of slack time and to manipulate resources in the process of time scheduling.
In other words, in this case the initial schedule of works the non-chronological network or time-range chart is flexible. In addition, the formation of the technological model of construction as a network chart will significantly save time for the construction manager later on, because during further planning, for example when drafting monthly schedules during adjust- ment of the provisional overall plan , the initial chart does not generally require redrafting as the technological and organi- sational references initially set out in the network chart will ensure adherence to the essential sequences and references if the situation alters.
The second great advantage of the network and time-range models are the simplicity and speed of computing, which is important for formulating option solutions as well as adjusting the schedule of work during construction, and when considering the deviation of actual work fill schedules from the estimates.
An example of a network chart reflecting the relations and conditionality of construction works appears in Figure 3. Earth works 1 Earth works 2 Installation of openings Exterior finishing works Roof works Tile floors Foundation Foundation works 1 works 2 Concrete floors Temporary Construction Building buildings and site set up of building Construction of Inside Inside Take facilities envelope 1 building envelope 2 plastering painting over Internal water supply and sewage works Interior electrical works installation of cables Internal heating and ventilation works On-site communication installations Construction of on-site roads Greenery works 2 On-site water supply Greenery works 1 On-site electric installations On-site sewage works Figure 3.
If the presented solutions satisfy the contract conditions, then the chart is linked to calendar dates giving the dates of the start of construction and hand over of the completed building as set out by the contract. If the critical path turns out to be longer than the duration of construction set in the contract, then the technological and organisational solutions set as the basis for the network chart must be re-evaluated, verifying that the new solutions are feasible from the point of view of construction site conditions.
When deciding which option to choose in order to shorten con- struction duration, economic calculations should be followed taking into consideration the aforementioned, and other, sub- stantial factors for each specific construction project.
After introducing the necessary changes to the work schedule, the calendared work schedule is calculated. It follows from this that the compilation of the construction site layout and time schedule of construction works are mutually related, therefore finding a satisfying solution might take sev- eral iterations of the plan.
At the same time, there must be a desire and will to be prepared for multiple calculations of resource allocation, the drafting of their workloads workers, construction machinery, materials, etc. Outline of site management after contract signature 43 The construction company should create a classification system for works corresponding to its specialisation that elaborates on inter-company labour consumption norms or the reciprocal norms of labour productivity.
The availability of this kind of data system would allow significant economies on costs and the time spent preparing construction time scheduling. Table 3. The numerical val- ues should only be interpreted as an example illustrating the considerable variation of labour efficiency by type of work to assure the expediency of compiling such standards as well as the need for their periodic adjustment. Therefore, it is practical for large construction companies and consulting site planning firms to form a cata- logue of standardised network charts that represents the majority of technological and organisational descriptions of buildings.
The catalogue of network charts of a custom main contractor usually consists of no more than ten to twenty types of charts. For that purpose it is necessary to aggregate subsequent site work element costs estimated by unit prices analogous to direct costs into 15 standardised groups corre- lated with the nomenclature of the aggregated costs of the bidding stage see Section 2. Therefore, feedback is used to automate the formation of norms for the first stage of site management.
This means that at this stage construction site costs are esti- mated as direct costs of the construction, given at the level of unit prices. The resource requirements appertaining to the bill of quantities should be given according to the resource ordering form used in the company, if such a form is created, and should be printed out separately.
Presented in Table 3. It is an illustrative list of costs of temporary works or corresponding vital resources in general construction, thus is not necessarily complete. The first column, numeration code , corresponds to the cost group codes relating to temporary works estimates in the bidding stage see Table 2. The nomenclature of costs and resources presented in Chapters 2 and 3 can be regarded as an example of the typical temporary works that usually occur in dwelling and office building projects, as shown in Table 3.
It is expedient for every build- ing company or potential group to elaborate on the analogous two-level classification for themselves, taking their own specia- lisations into account. Chapter 4 Suggestions for choosing construction cranes Chapter outline 4.
The chapter explains the restrictions, distances and measures one should consider while planning the construction site. The rules and calculations described in the following text guarantee the safe coordination of cranes and personnel on the site. These sugges- tions should be taken into consideration where construction site conditions allow. Unfortunately this is not applicable in all cases and it is certainly possible for several cranes to work simultaneously in close proximity.
All complicated situations, where following these safety requir- ements is impossible, have to be approached case by case. In these circumstances, special instructions for cranes and per- sonnel have to be compiled and supervision provided for all parties involved. It is important to understand that these instructions should not be general narratives but carefully cal- culated guidelines with danger distances, their identification signs, behaviour routines, etc. Every employee involved should understand the essence of different danger zones and what exactly they should do or be aware of before raising the hook.
Suggestions for choosing construction cranes 53 4. The distance between the building under construction and existing buildings, as well as safety requir- ements might affect the position and selection of the type of crane.
The lifting height and radius are determined by the chart in Figure 4. The overall dimension of the building and the parameters of the slope of the foundation recess, if necessary and the assem- bly parameters of precast elements are taken as a starting point. The vertical chart should be presented on the construction site layout CSL or on a separate sheet. Suggestions for choosing construction cranes 55 The required lifting capacity in tons is determined for the placement of various heavy precast elements in the most difficult lifting conditions of the crane.
For this purpose, the heaviest and furthest elements from the standing position are chosen, and their assembly parameters calculated. These results should be presented in the form presented in Table 4. The tower crane is chosen on the basis of a comparison between the assembly parameters of the elements hoisted and the lifting parameters of the crane, as shown in Table 4.
An example of presenting technical data of a suitable tower crane for particu- lar precast elements is presented in Figure 4. Here it should be borne in mind that determining the type of crane and its lifting capacity and the geometrical linking of the crane track to the building axes are iterative processes.
Assembly parameters of precast elements Lifting parameters of the crane Precast Assembly Assembly height m Assembly Trademark and technical Selected working parameters concrete weight t radius m data element Maximum radius m Working radius m Lifting capacity t Load take up Load take up Lifting height m Over lifting Tower height m Mounting Element Element device height device Total Total g1 g2 Gmax h1 h2 h3 h4 Hmax Rmax 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 1 Wall panel When determining the mounting height of the element see column 6 , the actual standing level of the crane measured from its bearing surface must be considered, not solely the assembly height set in the project.
The assembly radius of the crane column 11 depends on the assembly weight and the chosen assembly scheme — if one or several elements are mounted from one position, etc. Tower cranes moving on rails must be positioned next to the building under construction in order to comply with safety requirements, that is there must be safe distance between the closest parts of the building and the crane, and the edge of the a HC C 25 12 Figure 4.
Suggestions for choosing construction cranes 59 Building under construction Nearest longitudinal axis d2 Slewing radius of crane s1 D1 r1 Crane track axis Figure 4. The distance D1 of the crane track axis from the nearest longi- tudinal axis of the building is presented in Figure 4. The crane track can be built only on the grounds of a rati- fied outline project solution.
When setting the crane track in the proximity of a recess or trench with unsupported sides, their depth h5 must be taken into account along with the soil grain so that the edge of the crane track underlay nearest to the recess would be outside the collaps- ing prism of the recess slope, as shown in Figure 4.
While determining the distance d4 between the lower edge of the crane track underlay and rail axis, the particular parame- ters and requirements of chosen crane should be considered. When longitudinally linking the crane to the building under construction, the following must be determined: 1 the outermost stopping points of the crane in relation to the ends of the building; 2 the necessary length of the crane track.
Prior to the longitudinal link, the cross-linking of the crane must be completed, that is the location of the axis of the crane track has to be determined and executed as per the CSL. The outermost marks made on the axis of the crane track will determine the outermost stopping points of the crane. The calculated length of the crane track is adjusted upwards depending on the length of the track way link according to producer.
The longitudinal linking of the tower crane to the building under construction is presented in Figure 4. The safety distance between the slewing radius of the crane undercarriage or other overhanging part of the crane taken from reference books and the safety fence should be at least 0.
The outermost stopping points of the crane should be drawn on the CSL and marked on the ground so that the markings are clearly visible to the crane operator and slinger. Continuous danger factors occur where the displacement of loads takes place with the help of lifting devices assembling and loading machinery. Such areas must be surrounded by safety or signal fences. The meaning of safety fences here is structures that prevent an outsider accidentally gaining access to the dangerous area.
The impact range of danger factors is around the building and its floors, and within the working area of the crane, where assembly and demolition of building components takes place. These areas are surrounded with signal fencing. The meaning of signal fencing here is structures that caution against danger factors and mark the areas of restricted access on the construc- tion site.
When working in these areas, special organisational and tech- nical precautions must be applied that ensure safety. The danger areas around the building are presented in Figure 4. Assembly area here means the land surrounding the building, wherein assembled elements or units could fall. This area should be marked on the CSL.
The assembly area should be considered potentially dangerous. For a building up to 20 m high, the width of the area s is 5 m. If the building is higher, the width increases as shown in Figure 4.
Materials must not be stored in the assembly area, or in the crane track area iso- lated by signal fencing. The boundary of the assem- bly area is marked on the CSL, for example as shown in Figure 4. Only assembly cranes and lifting machinery can be placed within these boundaries. Suggestions for choosing construction cranes 67 crane, and these will be marked out on the CSL. In the building site area, passages within the assembly area must be covered with pents see Figure 3.
The service area working area of the crane R1 refers to the land that is within the boundary drawn by the crane hook when moving an assembled unit. In the case of a tower crane, this will be determined on the CSL by semicircles equal to the maximum reach of the jib Rmax necessary for assembly in the outermost working positions of the crane, and the connecting straight lines in case there are no limitations on the moving range of the load, which might derive from construction site conditions.
The load movement area R2 refers to the area where the farthest end of an assembled unit of maximum length hanging from the crane hook can move. The risk area of the crane refers to the area within which the removable load part may fall to the ground, taking into con- sideration possible deviation dispersion from the vertical when falling. The hoist danger area s also depends on the height of construc- tion and is presented in Figure 4. Impact areas of the tower crane in vertical section are presented in Figure 4.
The danger area over the building during construction of its upper floors is characterised by Figure 4. The danger areas that develop over the building are drawn on the CSL during the vertical linking of the crane, but similarly they are drawn on the technological map, if such is compiled. These options vary accord- ing to crane type as well as to the number of cranes used simultaneously. The location and quantities of other important construction site elements, such as temporary roads and storage sites, etc.
For long rectangular-shaped buildings, the tower cranes are positioned either on one or two sides of the building, depend- ing on the width of the building, the lifting parameters of the cranes and the construction site conditions. For long buildings the building under construction and the crane track are divided into several zones cycles.
The length of each zone should not be less than double the working radius of the crane plus 5 m. Within the limits of each zone only one crane is generally allowed to work, the other crane must work in another zone or stand still with the boom turned in the oppo- site direction. In Figure 4. It is possible to place hoists for lifting materials as well as peo- ple on the other side of the building during construction.
A deficiency of this crane positioning is that it is a relatively more complicated arrangement of the simultaneous work of two cranes with reference to provide job safety.
Another option for two cranes to work simultaneously is pre- sented in Figure 4. The crane positioning scheme and safety distances presented in Figure 4. Because of safety regulations, both cranes cannot work simul- taneously in the area of the same lateral axis of the building. The whole working front of the building, particularly on a long building, has to be divided into assembly zones cycles as when two cranes are positioned on one side of the building.
Suggestions for choosing construction cranes 77 addition, schemes for carrying units to the mounting sites must be determined, coordinate the crane working schedules and the immediate executors of tasks provided with timely and necessary information. One more option, the simultaneous work of two cranes posi- tioned between two buildings under construction, is depicted in Figure 4. The assembly height, that is the maximum required height of the hook Hmax, is calculated the same way as for the tower crane in Equation 4.
After choosing particular crane c7, ho and cB should be checked and amended if necessary. Based on the safety distances s3 and s4, point A is calculated, which is the nearest possible point of the crane boom towards the unit. After that it is possible to draw the horizontal projection of the boom l2.
If the unit is assembled with an extended lattice jib see Figure 4. When making the decision about a specific crane, a check should be made as to whether the calculated boom length, radius and lifting capacity are sufficient to mount the unit respective to the chosen assembly scheme of the crane. When using a mobile crane with varying boom lengths, the chart of lifting parameters varies by each of the various boom lengths.
In Table 4. Assembly parameters of precast elements Precast Assembly weight t Assembly height m Assembly concrete radius Element Load Total Mounting Over Element Load Total element m take up height lifting take up device device g1 g2 Gmax h1 h2 h3 h4 Hmax Rmax 1 2 3 4 5 6 7 8 9 10 11 1 Column This is done in similar fashion to the tower crane, as shown in Equations 4. The required lifting capacity and lifting height of the mobile crane is determined for placement of various weights of precast elements and for most difficult lifting conditions of a crane.
For this purpose, the most heavy and furthest elements from the crane standing position are chosen, and their assembly parameters are cal- culated, as shown in Table 4. The assembly radius Rmax is determined from the working scheme chosen, that is the sequence of mounting elements and the number of units planned to be lifted from the same standing position, etc. Based on the assembly parameters in Table 4.
The technical data for the chosen cranes is recorded, as shown in Table 4. The working parameters of crane then have to be set according to the assembly scheme chosen and compared with the calcu- lated assembly parameters of the precast elements see Table 4.
This can be accomplished by comparing the crane lifting charts with the required assembly parameters. The lifting charts can be presented differently by different crane producers see Figure 4. From this working radius, the chosen crane is able to lift to a height of 22 m, which also exceeds the required From this we can conclude that this crane is sufficient for lifting this particular column from the chosen working radius.
A similar exercise is completed for all other elements in the table. Table 4. Gmax G vs. The movement, positioning and operation of construction machinery in proximity to recesses, trenches and holes without extra support is allowed only at a distance determined in the plan of construction works, and must to be outside the margins of the recess slope collapse prism. The positioning of the crane can depend on the depth of the recess and the soil as shown in Figure 4.
If working with outriggers, the distance is taken from the centre of the outrigger. In contrast to the tower crane, this is done for every assembly position separately or only for the outermost positions. Suggestions for choosing construction cranes 89 7.
For mobile cranes equipped with a boom fall prevention device Figure 4. When lifting higher than 10 m, it is cal- culated similarly to s2 for tower cranes as shown in Figure 4. The width of the danger area of the slewing base of a lifting device as with an excavator is the sum of the radius of the slewing part and the safety distance 1 m. If the manufacturer has not given higher safety requirements in the technical documentation for the machine, the safety dis- tance within the working area of the device will be taken as being 5 m from its moving parts and appliances.
The protection zone of an aerial power line is in the form of areal space bounded on both sides by imaginary vertical lines along the areal line axes see Figure 4. See also the Electrical Safety Law. Surveillance area Danger area Bound of surveillance area Bound of danger area Figure 4.
Store of construction materials and use of lifting machinery are prohibited in the surveillance area without the agreement of the organisation that controls the line. Construction work in live overhead line surveillance area is acceptable only with written authorisation from the organi- sation that controls the line.
This means that this is not only a permission but exact instructions of how works should be arranged. The construction works have to be conducted under direct supervision of a white-collar worker responsible for job safety. One copy is given to the crane operator and the other to the person responsible for job safety foreman, supervisor, etc. If con- struction works are executed on the territory of an operating company, the work order must also have the signature of the person responsible from this company.
Before starting works in the surveillance area, the power must be disconnected from the overhead lines if possible. When voltage is kV or higher, construction machinery may only work under live overhead lines if the distance between any outlying part or removable unit of construction machinery and the lowest part of the overhead line is not smaller than the distances of surveillance area see Figure 4.
The safety distance s7 from the slewing axis of the crane to the nearest outermost wire of the power line Figure 4. The width of the area should be at least 5 m calculated from the outer con- tour of the hoist on the plan.
Safety requires that the upper ceiling of a building in service must not be in the danger area of the operating crane. If the lower floors of the building are still in the danger area of the crane, the windows facing the construction site must be covered with strong panels 9. The entrance facing the construction site 7 must be closed for the time of construction and taken to the safe side of the building 8.
The construction site fence bordering the building in service should be equipped with a protective screen The mini- mum width of the passage between the construction site fence and the building in service must be at least 1—1. For the situation presented in Figure 4. Suggestions for choosing construction cranes 97 4.
The restrictions applied are either compulsory or conventional. Compulsory restrictions are performed by installing sensors and limit switches. Conventional restrictions are oriented directly to the attention and experience of the crane operator, slinger or assembler.
The reference points for following conventional restrictions are marked on the construction site with clearly visible signs: red flags during daylight and additional red lights or a lantern gar- land during darkness warn the crane operators of when they are approaching the restricted area. The location of warning signs reference points and their design is indicated on the CSL. If they are relocated due to a change of assembly scheme, the crane operators and assemblers will be duly notified.
In order to ensure that conventional restrictions will be fol- lowed, the instruction of works management is drawn up for each specific situation. All particular requirements relating to crane operations are drawn onto the CSL, with necessary explanations providing an unambiguous and complete interpretation of the presented solution. Chapter 5 Suggestions for calculating resource requirements Chapter outline 5.
The timely and proper completion of access roads significantly influences the course and costs of construction. Permanent roads are generally built after levelling of the area and completion of drainage and utility networks. Those per- manent roads on the other hand that are usable for transport of construction materials and which do not interfere with overall construction site management may be built earlier together with temporary roads linking them to the unified road network of the construction site.
Suggestions for calculating resource requirements Temporary roads should preferably be built on the alignment of future permanent roads without laying the last coating. Only if temporary roads lead to temporary storage areas or to build- ings away from the alignments of permanent roads should the cost of temporary roads be calculated to the full extent.
Safer construction site traf- fic schemes are circular and one-way traffic schemes, which help to prevent vehicle collisions and traffic jams. When plan- ning roads, dead ends that make it difficult for drivers to turn the vehicle around to drive out of the construction site should be avoided.
It is unacceptable to build temporary road over under- ground utility networks and in direct proximity to the setting up of utility networks, as this could result in slope collapse and deformation of wearing surface. The construction site layout must precisely indicate with sym- bols and explanatory notes the entrance and exit roads, traffic directions, turning places, stopping area for vehicles for unloading and all the linking scales of the planned road units. On construction site with an area of over 5 ha, there must be at least two entrances on each side of the site.
In front of the construction site entrance, a traffic scheme must be installed for vehicles with clearly visible traffic signs no entrance, limited speed, etc. The width of the drive section on a single-lane road is 3. In case of heavier vehicles 25—30 t or more , the width of the road can increase up to 8 m. Suggestions for calculating resource requirements In the case of single-lane traffic, road extensions of up to 6 m are constructed with the length of 12—18 m to ensure passing space for vehicles travelling in opposite directions.
Road exten- sions are also built in the area of loading works, for example in the crane service area. Such passing places are made for at least every m section of road. The turning radius of the road is selected in accordance with the manoeuvring capability of vehicles, but is not less than 12 m. In curves, the width of the road must be increased to 5 m. Minimum visibility requirements on the road surface are at least 50 m for single-lane and 30 m for two-lane road.
The basis for selecting a road type is traffic density, the type and mass of construction machinery and the construction site geological and hydrogeological data.
If the bearing capacity and hydrogeological condition of the soil are good, then surface-dressed roads are generally built on smaller sites. Furthermore, it must be borne in mind that prestressed concrete surface slabs can be used three or four times against only one or two times for normal concrete slabs.
If a temporary road crosses a railway, boarding with a counter rail has to be installed in the crossing area and the counter rail has to be installed at the same level as the head of the rail. Surface-dressed roads are used for one-lane roads with a traffic density of up to three cars per hour where there are well- drained soils see Figure 5. Suggestions for calculating resource requirements of a grader.
In the case of heavy loads or an unfavourable sub-base, the road is reinforced with a profiled macadam, gravel or slag covering. The laid coverings are compacted by rolling. In the case of intense car traffic, the reinforced macadam, gravel or slag covering is laid on a sand sub-base compacted with heavy rollers beforehand.
The main construction materials — gravel, bricks, concrete elements, etc. Stores of materials in the storehouses should be as small as possible while still being enough to ensure uninterrupted work.
Construction site storage can be divided into open, closed and half-open storage. Open storage is intended for those materials that do not need protection from weather, such as gravel, con- crete and precast concrete elements, bricks, ceramic pipes, etc.
Open storage is mainly located within the range of the tower crane to avoid the need for separate conveyance of assembly units. Only in exceptional cases due to construction site restric- tions the precast elements can be stored outside the range of assembly crane.
Closed storage can be heatable or non-heatable. During construction inventory, temporary buildings are broadly used as closed storage.
Half open storage — pents — are built to store materials that need protection from either direct sunshine or rain, such as carpentry, soft roofing felt, etc. Roads must be laid to the storage areas. When storing assem- bly units within the working range of the crane, the stacking sites for various units must be selected so that, in order to con- vey the units to the planned position, the crane would have to move as little as possible and make a minimal number of boom turns.
For that purpose, units of the same type should be stored at various sites beside the building under construction. The heavier elements and the most frequently used materials must be stored closer to the crane. Requirements for storage of assembly units: 1 Precast elements must be stored in the technological order of assembly as close to the mounting site as possible.
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