The main parameters of a self-propelled jib crane are: lifting capacity, hook lifting height, boom radius, boom length.
1. Determine the lifting capacity of the crane(), T:
Where is the mass of the element, t; – mass of lifting devices, t; - mass of the rigging unit, t;
10+0,28+0=10,28
2. Determine the lifting height of the hook()m:
Where is the lifting height of the crane hook, m; – p distance from the level of the tap drain to the support of the mounted element, m; – the height reserve required to move the element above the previously installed ones, m, is taken to be at least 0.5 m; – height (thickness) of the element in the lifting position, m; – height of lifting devices, m; – height of the pulley in the tightened position (1.5 – 5 m).
0+0,5+0,4+1,2=2,1
3. Determine the boom lift height:
Where is the boom lift height;
4. Determine the boom reach ( ):
= 
,
Where e is half the thickness of the boom at the level of the top of the mounted element or a previously mounted structure (1.5 m); c – minimum gap between the boom and the mounted element (0.5-1 m); d – distance from the center of gravity to the edge of the element close to the boom; a – half of the crane base (approximately 1.5 m); Hstr – boom lifting height, m; hш – distance from the crane parking level to the boom rotation axis, m.
= 
=2,5
Required boom length(L page) is determined by the formula:
L page = 
L page = =2.3
where is the boom lift height, m; – distance from the crane parking level to the boom rotation axis, m;
Calculation of crane parameters for the installation of beams and trusses. The required lifting capacity of the crane (Q cr) is determined by formula (1).
The lifting height of the hook (N cr) is determined by formula (2).
The required boom radius (l str) is determined by formula (3).
The boom length (L str) is determined by formula (5).
Q cr =q el +q gr +q basic =1.75+9.8+0=1.55 t.
N cr =h o +h z +h el +h gr =8.4+1+3.3+3.6=16.3 m;
N str =N cr +h p =16.3+2=18.3 m.
l page = 
= l page = 
= 4.2 m.
5. Determine the length of the arrow:
L page = = = 17.0 m.
Calculation of crane parameters for installation of crane beams
1. Determine the load capacity:
Q cr =q el +q gr +q basic =4.5+0.9+5.2=10.64 t.
2. Determine the lifting height of the hook:
N cr =h o +h s +h el +h gr =0+0.5+0.9+3.2=4.6 m;
3. Determine the boom lift height:
N str =N cr +h p =18.4+2=20.4 m.
4. Determine the required boom reach:
l page = = l page = 
+1.5= 2.7 m.
5.N str =N cr +h p =4.6+1.5=6.1 m.
6. Determine the length of the arrow:
L page = = = 4.7 m.
Scheme for determining the installation characteristics of the crane when installing roof beams (trusses).
Scheme for determining the installation characteristics of the crane when installing roof beams (trusses)
Calculation of crane parameters for installation of coating slabs. The required lifting capacity of the crane (Q cr) is determined by formula (1).
The lifting height of the hook (H cr) is determined by formula (2). h o for the covering slab is determined by the formula h o = h 1 + h 2, where h 1 is the height of the column from the crane parking level; h 2 – height of the beam (truss), m.
The boom lift height (N str) is determined by formula (4).
Minimum required boom radius(l page) is determined by formula (3).
Definition scheme installation characteristics crane when installing covering slabs.
The required boom radius for mounting the end plate is determined by the formula:
l page = l 2 pages min + ,
where is the span of the building, m; – width of the coating slab, m.
Boom length(L page) is determined by formula (5).
1. Determine the load capacity:
Q cr =q el +q gr +q basic =3.31+5.7+0=9.01 t.
2. Determine the lifting height of the hook:
h o =8.4+3.3=11.7 m.
N cr =h o +h z +h el +h gr =11.7+0.5+4.5+3.31=20.01 m;
5.8 = 6.4 (h 2) – 0.7 (column depth in the glass).
3. Determine the boom lift height:
N str =N cr +h p =20.01+2=22.01 m.
4. Determine the required boom reach:
l page = = l page = 
= 15.4 m.
5. Determine the required boom reach for mounting the end plates:
l page = 
= 15.8 m.
6. Determine the length of the arrow:
L page = = = 15.8 m.
Design parameters
Based on certain required parameters of lifting capacity, hook lifting height, boom radius, boom length, boom radius, boom length, two cranes are selected from reference sources whose characteristics correspond to the required ones or exceed them (by no more than 20%).
The tap is selected as a result of comparing the parameters that are presented in table.
In addition, it is advisable to carry out an economic comparison of the preferred cranes, comparing the cost of machine shifts. At the same cost of machine shifts, cranes with lower engine power and other more favorable indicators are preferable.
Conclusion. Taking into account the required technical parameters select the MGK16 tap.
The selection of a crane is made according to three main parameters:
Load capacity;
Hook reach;
The height of the lift, and in some cases the depth of lowering the hook.
When choosing a crane for construction work use working drawings of the object being built, taking into account the dimensions, shape and weight of prefabricated elements to be installed. Then, taking into account the installation location of the crane, the largest required boom reach and the required maximum lifting height are determined.
Crane capacity– a payload of payload lifted by a crane and suspended using removable lifting devices or directly to non-removable lifting devices. For some imported cranes, the mass of the lifted load also includes the mass of the hook cage, which must be taken into account when selecting a crane.
The required lifting capacity of the crane at the corresponding reach is determined by weight heaviest load with removable load-handling devices (grab, electromagnet, traverses, slings, etc.). The mass of the load also includes the mass of attachments attached to the mounted structure before it is lifted, and reinforcement structures load rigidity.
Q – crane lifting capacity;
P gr – mass of the lifted load;
P gr.pr. – weight of the load-handling device;
P n.m.pr. – mass of mounted mounting devices;
P k.u. – a lot of structures to strengthen the rigidity of the lifted element and container.
When choosing a crane for construction and installation work, it is necessary to ensure that the weight of the load being lifted, taking into account lifting devices and containers, does not exceed the permissible (certified) lifting capacity of the crane. To do this, it is necessary to take into account the maximum weight of the installed products and the need to move them by crane for installation to the most distant design position, taking into account the permissible lifting capacity of the crane at a given boom radius.
When selecting cranes with variable reach, it is necessary to pay attention Special attention that the lifting capacity of these cranes depends on the reach.
Necessary working radius R р is determined by the horizontal distance from the axis of rotation of the rotating part of the crane to the vertical axis of the load-handling member.
The working reach of the crane is calculated using the following options:
When tying up cranes with a slewing tower
R р – required working radius;
b – the distance from the building axis closest to the crane to the point farthest from the crane in the direction perpendicular to the axis of movement of the crane;
S – distance from the axis of rotation of the crane to the nearest axis of the building;
a is the distance from the axis of the building to its outer edge (protruding part);
n – approach clearance;
R p – the largest radius of the rotating part of the crane on the side opposite to the boom.
Figure 8.1 – Linking the mounting mechanism. Attaching a jib crane to a building
Figure 8.1, 8.2 shows the binding of the mounting mechanism
Figure 8.2 – Linking the mounting mechanism. Attaching a tower crane to a building
Distances a and b are determined from the working drawings of the building.
The approach clearance is taken as the distance between the protruding parts of a crane moving along ground rail tracks (its rotary or other most protruding part) and the nearest external contour of the building (including its protruding parts - canopies, cornices, pilasters, balconies, etc.), temporary construction devices located on or near a building (scaffolding, remote platforms, protective canopies, etc.), as well as buildings, stacks of cargo and other objects, must be in accordance with Article 2.18.6 PB 10-382-00 from the level ground or working platforms at a height of up to 2000 mm, at least 700 mm, and at a height of more than 2000 mm - at least 400 mm. For cranes with a rotating tower and the number of sections in the tower of more than two, this distance is taken to be at least 800 mm over the entire height due to the possible deviation of the tower from the vertical.
The distance between the rotating part of jib self-propelled cranes, in any of their positions, and buildings, stacks of cargo, scaffolding and other items (equipment) must be at least 1000 mm.
The largest radius of the rotating part of the crane on the side opposite to the boom is taken according to the crane's passport.
When installing the crane near unsupported slopes of pits, trenches or other excavations
For tower cranes
S=r+C+0.5d+0.5K
r is the distance from the axis of the building to the base of the pit slope;
C – distance from the base of the pit slope (excavation) to the edge of the ballast prism;
d – width of the base of the ballast prism
K – crane track track. (Figure 8.3)
Figure 8.3 – Approach dimensions
d=Sop.e.+2δ+3hb
S op.e. – size of the supporting element across the rail thread, mm;
δ – side arm of the ballast layer (δ≥200 mm);
3h b – size of two projections of slopes of the ballast layer with thickness h b, mm.
The following should be used as supporting elements:
When the load from the wheel on the rail is up to 250 kN inclusive - half sleepers or reinforced concrete slabs;
When the load from the wheel on the rail is over 250 kN - reinforced concrete beams.
General types and the dimensions of the supporting elements are given in G.3 of Appendix G SP 12-103-2002 “Ground crane rail tracks. Design, design and operation."
The slopes of the side sides of the ballast layer must be made with a slope of 1:1.5, therefore the size of two projections of the slopes of the ballast layer with a thickness of h b is 3h b.
The thickness of the ballast layer is determined by the project based on calculations and depends on the load on the crane wheel, the type of soil base, ballast material and the design of under-rail support elements.
The approximate ballast thickness is given in Table 8.1
Table 8.1 - Approximate ballast thickness
2. The distance between the axes of the sleepers should be 500 mm with permissible deviations of ±50 mm.
3. Crushed stone from natural stone of fraction 25-60 mm, gravel and gravel-sand mixture of fraction 3-60 mm (gravel) and 0.63-3 mm (sand) by weight no more than 20% should be used as crushed stone ballast.
4. For the manufacture of crane rail tracks, new or old rails of suitability groups I and II must be used.
For jib cranes r is the distance from the axis of the building to the base of the pit slope (excavation); C – the distance from the base of the pit slope (excavation) to the nearest support of the lifting machine, determined according to Table 8.2;
Table 8.2 - Minimum distances horizontally from the base of the excavation slope to the nearest machine supports (SNiP 12-03-2001 clause 7.2.4) (C)
To determine the characteristics of the soil when installing a lifting machine near a pit (excavation), it is necessary to be guided by an engineering-geological conclusion about soils, while if there are heterogeneous soils in the slope, the approach of the lifting machine is determined by one type of soil with
worst performance
(on the weakest soil) (Figure 8.4, 8.5).
Figure 8.4 - Installation of a rail crane at the pit slope Figure 8.5 - Installation of jib cranes at excavation slopes when installing a crane near buildings with basements or other underground hollow structures
When installing lifting machines near buildings (structures) with basements or other underground hollow structures, design institutes (project authors) must calculate
For tower cranes
2. The distance between the axes of the sleepers should be 500 mm with permissible deviations of ±50 mm.
r is the distance from the axis of the building to the outer edge of the basement wall closest to the tap;
C – distance from the outer edge of the basement wall closest to the crane to the nearest support of the lifting machine;
d – width of the base of the ballast prism;
K – crane track track;
L op is the size of the track or base of a crawler crane, and for lifting machines with outriggers - the size of the support contour.
Figure 8.6 - Installation of lifting machines near buildings with a basement, without calculating the extrusion of walls from crane loads
The approach of an attached crane to a building (structure) is determined by the minimum reach, which ensures installation of the crane closest to the tower structural elements buildings, taking into account the dimensions of the crane foundation and the conditions for attaching the crane to the building.
where Rmin is the minimum crane hook reach
Distances a and b are determined from the working drawings of the building in the part of the building where the crane is supposed to be installed.
The minimum reach of the crane hook is taken according to the crane passport.
The design of the foundation of an attached crane in each specific case is determined by calculations performed by a specialized organization.
The design for fastening the attachment crane to the building structure is developed by a specialized organization and agreed upon with the author of the building design.
Required lifting height h p is determined from the vertical installation mark of lifting machines (cranes) and consists of the following indicators:
height of the building (structure) h from the zero level of the building, taking into account the installation (parking) marks of the cranes to the top level of the building (structure) (upper installation horizon);
headroom equal to 2.3 m from the conditions safe production work at the top level of the building where people may be;
the maximum height of the transported load h gr (in the position in which it is moved) taking into account the mounting devices or reinforcement structures attached to the load,
length (height) of the load-handling device h gr.pr. in working position as shown in Figure 8.7. 8.8
where n is the difference between the elevations of the cranes and the zero elevation of the building (structure).
Figure 8.7 – Linking the mounting mechanism
Required lowering depth h op is determined from the elevation of the lifting crane vertically as the difference between the height of the building (structure) - when installing the crane on the structures of the structure being built, or the depth of the pit and the amount minimum heights load and load-handling device, as shown in Figure 4, with an increase in h op by 0.15-0.3 m to loosen the tension of the slings when unslinging.
Figure 8.8 – Linking the mounting mechanism
P gr - mass of the lifted (lowered) load;
h gr - height of the load;
h gr.pr. - length (height) of the load-handling device;
h h - height of the building;
h op - height (depth) of lifting (lowering);
Ur.s.k. - crane parking level;
Ur.z. - ground level;
Ur.d.k. - level of the pit bottom;
Ur.p. - floor (roof) level.
(when the crane is parked on the ground)
(when the crane is parked on the roof)
When choosing a crane with a luffing jib, it is necessary that a distance of at least 0.5 m be maintained from the boom dimensions to the protruding parts of the building, and at least 2 m vertically to the ceiling (covering) of the building and other areas where people may be located, as shown in Figures 1 and 2. If the crane boom has a safety rope, the indicated distances are taken from the rope according to Figure 8.9.
Required working radius;
Weight of the load being lifted;
The largest radius of the turning part of the crane;
Building size;
Lift height mark;
Figure 8.9 - Vertical tie-down of jib cranes with safety rope
For the installation of structures or products that require smooth and precise installation, cranes with smooth landing speeds are selected. The crane's compliance with the hook lifting height is determined based on the need to deliver products and materials to the maximum height, taking into account their dimensions and the length of the slings.
Cross-linking of crane tracks of tower cranes.
After selecting the crane, its final transverse alignment is carried out, with the design of the crane runways being clarified.
Longitudinal binding of crane tracks of tower cranes
To determine the extreme positions of the crane, notches are sequentially made on the axis of movement of the crane in the following order:
from the extreme corners of the outer dimension of the building on the side opposite to the tower crane - with a compass solution corresponding to the maximum working reach of the crane boom (Figure 8.10);
from the middle internal contour buildings - with a compass solution corresponding to the minimum reach of the crane boom;
from the center of gravity most heavy elements– a compass solution corresponding to a certain boom radius according to the load characteristics of the crane.
The extreme notches determine the position of the center of the valve in the extreme position and show the location of the heaviest elements.
Based on the found extreme crane stops, the length of the crane runways is determined:
or approximately
L p.p. – length of crane tracks, m;
1 cr – the distance between the extreme crane stands, determined from the drawing, m;
N cr – crane base, determined from reference books, m;
1 brake – the magnitude of the braking distance of the crane, taken to be at least 1.5 m;
1 dead end – the distance from the end of the rail to the dead ends is 0.5 m.
a - determination of the outermost parking positions from the condition of the maximum working reach of the boom;
b - determination of the outermost parking lots from the condition of minimum boom outreach;
c - determination of the outermost parking positions from the condition of the required boom reach;
d - determination of the extreme positions of the crane;
d - determination of the minimum length of crane runways;
Figure 8.10 - Determination of the extreme crane positions
The determined length of the crane runways is adjusted upward, taking into account the multiple length of the half-link, i.e. 6.25 m. Minimum permissible length crane tracks according to the rules of Rostekhnadzor is two links (25 m). Thus, the accepted path length must satisfy the following condition:
6.25 – length of one half-link of crane runways, m;
n sv – number of half-links.
If it is necessary to install the crane on one link, i.e., on a lay-up, the link must be laid on a rigid foundation that prevents subsidence of the crane tracks. Such a basis can be prefabricated foundation blocks or special prefabricated structures.
Linking crane runway fencing
The crane runway fencing is tied based on the need to maintain a safe distance between the crane structures and the fencing.
The distance from the axis of the rail closest to the fence to the fence is determined by the formula
– crane track width, m (taken from reference books);
– taken equal to 0.7 m;
– radius turntable(or other protruding part of the crane) are taken according to the crane’s passport data or reference books.
For tower cranes without a rotating part, it is maintained from the crane base. In final form with designation necessary details and dimensions, the binding of the paths is made in accordance with Fig. 8.11
The outermost stands of the tower crane must be tied to the axes of the building and marked on the road surface and the terrain with landmarks clearly visible to the crane operator and slingers.
e - linking of crane tracks;
1 - extreme crane stops; 2 - linking the outer parking lot to the axis of the building; 3 - control weight; 4 - end of the rail; 5 - place of installation of the dead end; 6 - crane base
Figure 8.11 – Path binding
The crane operator must have a clear view of the entire working area. The work area of the tower crane must cover the height, width and length of the building under construction, as well as the storage area for assembled elements and the road along which cargo is transported.
When tying up tower cranes, you should take into account the need for their installation and dismantling, paying special attention to the position of the boom and the counterweight located at the top in relation to the building (structure) being erected. During installation and dismantling of these cranes, the boom and the counterweight located at the top must be above the free area, i.e. should not fall on buildings under construction or existing ones and other obstacles.
Installation and dismantling of cranes is carried out in accordance with the instructions for their installation and operation.
calculate the crane's operating areas;
identify operating conditions and, if necessary, impose restrictions on the crane’s operating area
Calculation of crane lifting capacity
Initial data for calculating the crane:
Load lifting height, m - 5
Load lifting speed, m/s - 0.2
Boom radius, m - 3.5
Operating mode, duty cycle % - 25 (average)
The drive of the boom lifting and lifting mechanism is hydraulic.
Fig.1
We determine the crane's lifting capacity based on the stability equation.
hence the maximum permissible weight of the cargo will be equal to:
Where, Ku - load stability coefficient, Ku = 1.4;
Mvost - restoring moment;
Mopr - overturning moment;
GT is the weight of the tractor, from technical specifications GT = 14300 kg;
Gg is the weight of the load;
a is the distance from the center of gravity of the tractor to the tipping point;
b is the distance from the tipping point to the center of gravity of the load.
Calculation of the load lifting mechanism, boom
1) determine the multiplicity of the pulley, depending on the load capacity Q, according to the table (given below). (a=2)
2) Select the hook and the design of the hook suspension according to the atlas (hook No. 11)
3) I determine the efficiency of the chain hoist (h):
Where s is the efficiency of the pulley block
Bypass block efficiency
4) Determine the force in the rope:
I choose a rope type LK-R 6CH19 O.S. diameter 13
Where: d to - rope diameter (d to = 13 mm)
I accept Dbl = 240 mm. D b - I take more D b in advance. D b = 252 mm. For convenient placement of the gear coupling half inside the drum.
Hydraulic motor 210.12
P motor = 8 kW
n = 2400 min -1
I motor = 0.08 kgm 2
Shaft diameter = 20 mm.
U r = 80 (CZU - 160)
We take the value D b = 255 mm, rounding the calculated diameter to the nearest of the series of numbers R a 40 according to GOST 6636 - 69, while the actual lifting speed will increase slightly.
The discrepancy with the given speed is about 0.14%, which is acceptable.
Fig.2
R k = 0.54*d k = 0.54*13 = 7.02 ? 7 mm
Determine the wall thickness:
Z slave - number of working turns:
where t is the cutting step
Allowable compressive stress for cast iron SCh15 = 88 MPa
<3 составляет не более 10%, величину которого можно не учитывать, в нашем примере lб/Dб = 350/255 = 1,06 < 3 в этом случае напряжения изгиба будут равны:
With D k = 14.2 mm => stud thread = M16 d 1 = 14.2 mm stud material St3, [d] = 85
18) Brake selection.
T t?T st* K t,
T t = 19.55*1.75 = 34.21 Nm
I choose a band brake with a hydraulic drive, with a nominal T = 100 N*m
Brake pulley diameter = 200 mm.
T r = T st *K 1 *K 2 = 26.8 * 1.3 * 1.2 = 41.8 N * m
I choose an elastic bush-pin coupling with a brake pulley w = 200 mm.
T out = T st *U M *z M = 26.8*80*0.88 = 1885 N*m
Selected gearbox Ts3U - 160
U ed = 80; Tout = 2kNm; F k = 11.2 kN
21) Checking the start time.
The acceleration value at start corresponds to the recommendation for lifting mechanisms during loading and unloading operations [J] up to 0.6 m/s 2 is allowed. The slowness is due to the characteristics of the hydraulic drive.
The braking torque is determined by the selected engine T brake = 80 N*m.
Acceleration when braking:
The amount of deceleration during braking corresponds to the recommendations for lifting mechanisms during unloading and loading operations ([i] = 0.6 m/s 2).
Calculation of the boom lifting mechanism
4) Determine the force in the rope:
5) Selection of rope. According to the rules of ROSGORTEKHNADZOR, the rope is selected according to the breaking force specified in the standard or in the factory certificate:
Where: K is the safety factor, selected from the table (for average operating mode - 5.5)
I choose a rope type LK-R 6CH19 O.S. diameter 5.6 mm.
6) I determine the diameter of the blocks from the condition of the durability of the ropes according to the ratio:
Where: dk - rope diameter (dk = 5.6 mm)
e is the permissible ratio of the drum diameter to the rope diameter.
We accept according to ROSGORTEKHNADZOR standards for cranes general purpose and average operating mode e = 18.
I accept Dbl = 110 mm. D b - I take more D b in advance. D b = 120 mm. For convenient placement of the gear coupling half inside the drum.
7) I determine the power required to select the engine, taking into account the drive mechanism:
8) I select a hydraulic motor according to the value of P st from the atlas:
Hydraulic motor 210 - 12
P motor = 8 kW
n = 2400 min -1
T start = 36.2 Nm (starting), maximum 46 N*m.
I motor = 0.08 kgm 2
Shaft diameter = 20 mm.
9) Determine the rated torque on the motor shaft:
10) Determine the static torque on the motor shaft:
11) Determine the rotation speed of the drum:
12) Determine the gear ratio of the mechanism:
13) I select the gear ratio of a standard 3-speed spur gearbox from the atlas:
U r = 80 (CZU - 160)
14) I specify the drum rotation frequency:
15) I specify the diameter of the drum; in order to maintain the specified speed of lifting the load, it is necessary to increase the diameter, since its rotation speed decreased to 30 when choosing the value of the first number of the standard gearbox.
We take the value D b = 127 mm, rounding the calculated diameter to the nearest of the series of numbers R a 40 according to GOST 6636 - 69, while the actual lifting speed will increase slightly.
The discrepancy with the given speed is about 0.25%, which is acceptable.
16) Determine the dimensions of the drum:
Fig.2
I determine the groove cutting step for the rope:
R k = 0.54*d k = 0.54*5.6 = 3.02? 3 mm
Determine the wall thickness:
I determine the diameter from the bottom of the cutting groove:
I determine the number of threading turns:
Where: Z cr = 3, number of fastening turns
Z spare = 1.5 number of spare turns
Z slave - number of working turns:
17) Calculation of the drum for strength.
where t is the cutting step
Allowable compressive stress for cast iron SCh15 = 88 MPa
2) bending stress d and torsion f for short drums lb/db<3 составляет не более 10%, величину которого можно не учитывать, в нашем примере lб/Dб = 109,4/127 = 0,86 < 3 в этом случае напряжения изгиба будут равны:
We determine the equivalent voltages:
18) Calculation of fastening the rope to the drum.
I determine the force of the rope branch to the fastening plate:
where e = 2.71; f = 0.15; b = 3*p
where: K T - 1.5 friction force safety factor
Z m - 2 number of studs or bolts
The size of the lining is selected based on the diameter of the rope
With D k = 6.9 mm => stud thread = M8 d 1 = 6.9 mm stud material St3, [d] = 85
18) Brake selection.
I determine the static torque during braking:
The brake is selected taking into account the braking torque reserve i.e.
T t?T st* K t,
where: Kt - braking torque safety factor.
T t = 2.01*1.75 = 4.03 Nm
I choose a band brake with a hydraulic drive, with a nominal T t = 20 N*m
Brake pulley diameter = 100 mm.
19) Selection of coupling. The choice of coupling should be made according to the calculated torque:
T r = T st *K 1 *K 2 = 2.01 * 1.3 * 1.2 = 3.53 N * m
I choose an elastic bush-pin coupling with a brake pulley w = 100 mm.
20) Selecting a gearbox. It is produced according to the gear ratio U M = 80, the torque on the output shaft T out and the cantilever load F k on the output shaft.
T out = T st *U M *z M = 2.01*80*0.88 = 191.2 N*m
Selected gearbox Ts3U - 160
U ed = 80; T out = 2 kN*m; F k = 11.2 kN
21) Checking the start time.
Тbrake = ±Тst.brake. +T in1.t +T in2.t
The (+) sign should be taken when lowering the load, because in this case the braking time will be longer.
Moment of resistance of the inertia forces of the rotating parts of the drive at startup:
Moment of resistance due to drum inertia forces:
The amount of acceleration at startup corresponds to the recommendation for lifting mechanisms during loading and unloading operations. [J] up to 0.6.
21. Checking braking time:
Tbr = ±Tst.t. +T in1t +T in2t
Where: T brake - average braking torque of the engine; the plus sign should be taken when lowering the load, since in this case the braking time will be longer;
T st.t - static moment of resistance during braking;
T in1t - moment of resistance from the inertia forces of the rotating parts of the drive during braking;
T in2t - moment of resistance from the inertial forces of translationally moving masses during braking.
The braking torque is determined by the selected engine T brake = 25 N*m.
I determine the moments of resistance during braking:
Acceleration when braking:
The amount of deceleration during braking corresponds to the recommendations for lifting mechanisms during unloading and loading operations ([i] = 0.6 m/s 2).
Section 4. Calculation of metal structures
tractor pipe layer crane boom
Calculation of metal structures includes:
1) calculation of the strength of the metal structure of the boom
2) calculation of the strength of the block axis
3) calculation of the strength of the boom support axis
The load acting on the axis of the rope guide block is Q = 2930 kg = 29300 N. The block is mounted on the axis on 2 radial bearings. Since the axis of the guide block is stationary and is under the influence of a constant load, the static bending strength is calculated. The calculated axis can be considered as a two-support beam, freely located on supports, with two concentrated forces P acting on it from the bearings. The distance (a) from the axle support to the load is taken to be 0.015 m.
Rice. 3
The diagram of bending moments is a trapezoid, and the value of the bending moment will be equal to:
T IZG =P*a=(Q/2)*a=2.93*9810*0.015/2=215.5 N
The required axle diameter is determined from the following formula:
From a series of numbers I accept standard value block axis diameter d=30 mm.
We calculate the strength of the arrow axis.
where S cm is the crushing area, S cm = рdД,
where D is the thickness of the eyelet, m.
S cm = p*0.04*0.005 = 0.00126 m2,
Fcm = G str * cos(90-b) + G gr * cos(90-b) + F pcs * cosg + F k * cosv,
where: b - boom angle,
c - angle of inclination of the cable of the load lifting mechanism,
g - angle of inclination of the boom lifting mechanism cable.
F cm = 7*200 * cos(90-b) + G gr * cos(90-b) + F piece * cosg + Fk * cosв = 37641.5 N,
From here we take the diameter of the arrow axis to be 40 mm.
At the same time, let’s calculate the compression tension of the arrow:
Taking l as 140, taking the embedment coefficient as 1, we determine that the cross-sectional area is equal to:
S = 140*ts / F szh = 140*0.45 / 37641.5 = 16.73 cm 2,
We also find the required radius of gyration:
r = lpage / 140 = 0.05 m = 5 cm.
We accept the 20-P channel according to the prototype: r = 8.08 cm, S = 87.98 cm 2, W = 152 cm 3.
We calculate the compressive stress:
We are looking for a bending force acting perpendicular to the inclination of the arrow.
M izg =l str *=11951.9 N*m
The moment of resistance will be equal to
W = 2W = 2*152 = 304 cm3.
yizg = 11951.9 / 304 = 39.32 MPa,
which is less than acceptable.
Let's calculate the equivalent voltage:
which is also less than acceptable.
Main technical parameters of the self-propelled jib crane:
N tr– required boom lift height, m;
L tr- required boom radius, m;
Q tr – required hook load capacity, t;
I page- required boom length, m.
To determine the technical parameters of the crane, it is necessary to select slinging devices for the installation of prefabricated elements. The data is entered into the table “Slinging devices for installation of prefabricated elements” according to the form.
Scheme of building installation (for a covering slab) using a self-propelled jib crane:
Required boom lifting height - N tr determined by the formula:
N tr =h 0 + h s + h e + h s + h p, m,
Where h 0- excess of the support of the mounted element above the crane parking level, m;
h z– height reserve (not less than 0.5 m according to SNiP 12.03.2001), m;
h e- height of the element in the mounted position, m;
h s- sling height, m;
h p- height of the cargo pulley (1.5 m), m.
N tr = m
Required range of arrows - L tr determined by the formula:
L tr = (N tr - h w)x(c+d+b/2)/(h p +h c)+a, m,
Where N tr- required boom lift height;
h sh
With- half of the boom cross-section at the level of the top of the mounted element (0.25 m), m;
d– safe approach of the boom to the mounted element (0.5-1m), m;
b/2- half the width of the mounted element, m;
h p- height of the cargo pulley (1.5 m), m;
h s- sling height, m;
A
…………… m
Required load capacity mounting hook Q tr- determined by the formula:
Q tr =Q e +Q s, T,
Where Q e– weight of the mounted element, t;
Q with- weight of the sling device, i.e.
Q tr determined from the installation conditions of the heaviest element.
Q tr = …………. + ……………. = ……………. tn
Required boom length - I page determined by the formula:
I str = (N tr -h w) 2 + (L tr -a) 2, m,
Where N tr- required boom lift height, m;
L tr- required boom radius, m;
h sh- height of the boom heel hinge (calculate 1.25-1.5 m), m;
A- distance from the center of gravity of the crane to the heel of the boom hinge (1.5 m).
I page = =…………… m
Selecting a Truck crane ……………….. with a lifting capacity of ……t
The main lattice boom of the crane has a length of ………….m
Technical characteristics with boom length …………….m:
Load capacity on outriggers at boom outreach, t
The greatest - ……………..
The least – ………………….
Boom radius, m
The largest one is …………….
The smallest one is ……………….
Height of hook lift when boom extends,
The greatest - ………………..
The least - …………………
3.1. Selection of a lifting crane.
3.1.1. The crane is selected according to three main parameters: lifting capacity, reach and lifting height, and in some cases, lowering depth.
3.1.2. The crane operator must have an overview of the entire working area. The work area of the tower crane must cover the height, width and length of the building under construction, as well as the storage area for assembled elements and the road along which cargo is transported.
3.1.3. When choosing a crane for construction and installation work, it is necessary to ensure that the weight of the load being lifted, taking into account lifting devices and containers, does not exceed the permissible (certified) lifting capacity of the crane. To do this, it is necessary to take into account the maximum weight of the installed products and the need to move them by crane for installation to the most distant design position, taking into account the permissible lifting capacity of the crane at a given boom radius.
3.1.4. For the installation of structures or products that require smooth and precise installation, cranes with smooth landing speeds are selected. The crane's compliance with the hook lifting height is determined based on the need to deliver products and materials to the maximum height, taking into account their dimensions and the length of the slings. When choosing a crane for construction work, working drawings of the object being built are used, taking into account the size, shape and weight of the prefabricated elements to be installed. Then, taking into account the installation location of the crane, the largest required boom reach and the required maximum lifting height are determined.
3.1.5. The lifting capacity of a crane is a payload of useful mass lifted by a crane and suspended using removable lifting devices or directly to non-removable lifting devices. Jib slewing cranes provide the ability to lift loads in all positions of the rotating part. For some imported cranes, the mass of the lifted load also includes the mass of the hook cage, which must be taken into account when developing the PPR.
The required lifting capacity of the crane at the corresponding reach is determined by the mass of the heaviest load with removable lifting devices (grab, electromagnet, traverse, slings, etc.). The weight of the load also includes the weight of attachments mounted on the mounted structure before it is lifted, and structures for reinforcing the rigidity of the load.
The crane's lifting capacity () must be greater than or equal to the mass of the load being lifted, plus the mass of the lifting device, plus the mass of mounted mounting devices, plus the mass of the structures that reinforce the rigidity of the lifted element.
For variable reach cranes, the lifting capacity depends on the reach.
3.1.6. The required working reach is determined by the horizontal distance from the axis of rotation of the rotating part of the crane to the vertical axis of the load-handling member as shown in Figure 1.
Lift height mark;
Required working radius;
The largest radius of the rotating part of the crane on the side opposite to the boom;
Height of the building (structure);
Lifting height;
Crane track track;
The minimum distance from the protruding part of the building to the axis of the rail, 
;
The size of the zone in which people are prohibited is determined in the PPR;
Approach clearance;
Rail head mark;
Main elevations;
________________
* Due to the possible deviation from the vertical of a rotating tower with a height of more than two sections and a cargo pulley, the approach clearance should be taken as 800 mm instead of 400 mm over the entire height.
** From the most protruding part of the tap.
Figure 1 - Attaching a tower crane to a building
3.1.7. The required lifting height is determined from the installation level of lifting machines (cranes) vertically and consists of the following indicators: the height of the building (structure) from the zero level of the building, taking into account the installation (parking) marks of the cranes to the top level of the building (structure) (upper installation horizon), headroom equal to 2.3 m from the conditions of safe work at the top level of the building where people may be, the maximum height of the moved load (in the position in which it is moved) taking into account the mounting devices or reinforcement structures attached to the load, length ( height) of the load-handling device in the working position as shown in Figures 1, 2, 3.
where is the difference between the elevations of the cranes and the zero elevation of the building (structure).
Load height characteristics of the crane
Required working radius;
Weight of the load being lifted;
Lifting height;
Building height;
Height of the lifted (moved) load;
Length of lifting device;
Distance from the axis of the crane to the axis of the building;
The size of the zone in which people are prohibited;
Dimensions between the axes of the building;
The distance from the axis of the building to its outer edge (protruding part);
Approach clearance;
Lift height mark;
Figure 2 - Linking the jib crane to the building
Required working radius;
The largest radius of the turning part of the crane;
Pit depth;
Height of the lifted (moved) load;
Length of lifting device;
Lifting height;
Crane track track;
Distance from the axis of the crane to the axis of the building;
Dimensions between the axes of the building;
Distance from the base of the pit slope to the edge of the ballast prism;
Distance from the axis of the building to the base;
Distance from the rail axis to the rail crane track fence;
Width of the base of the ballast prism;
Lift height mark;
Rail head mark;
Main marks of building structures.
Figure 3 - Installation of a rail crane at the pit slope
3.1.8. The required lowering depth is determined from the installation mark of the load-lifting crane vertically as the difference between the height of the building (structure) - when installing the crane on the structures of the structure being built, or the depth of the pit and the sum of the minimum heights of the load and the load-handling device, as shown in Figure 4, with an increase of 0 ,15-0.3 m to ease the tension of the slings when unslinging.
where is the height of the building (structure) from the zero mark to the floor (roof) mark on which the crane is installed;
Depth of the pit (structure) from the ground level to the bottom mark of the pit (structure);
The difference between the ground elevations and the zero elevation of the building (structure);
The difference between the elevation of the crane and the elevation of the ceiling (roof), or the surface of the earth on which the crane is installed.
Mass of the lifted (lowered) load;
Load height;
Length (height) of the load-handling device;
Building height;
Height (depth) of lifting (lowering);
Crane parking level;
Ground level;
Pit bottom level;
Floor (roof) level.
(when the crane is parked on the ground)
(when the crane is parked on the roof)
Figure 4 - Installation of cranes for lowering (raising) loads below the parking level
3.1.9. In cramped conditions, where preschool and educational institutions, when choosing a crane, it is recommended to use stationary cranes.
3.2. Selection of crane-manipulator.
3.2.1. The selection of loader cranes is carried out in the same way as lifting cranes according to the main parameters: lifting capacity, reach, lifting height and lowering depth.
In this case, the load-height characteristics of the manipulator crane are taken into account for all combinations of its operating conditions and the design under which operation is envisaged.
3.2.2. The required lifting capacity of the crane and working reach are determined similarly to the instructions in paragraphs 3.1.5 and 3.1.6.
3.2.3. The required lifting height is determined from the vertical mounting mark of the crane-manipulator unit (CMU) on the vehicle to the load-handling device, which is in the upper position, the maximum required to perform the work, as shown in Figure 5.
where is the height of the crane-manipulator mounting on the vehicle;
Load height;
Height (length) of the load-handling device;
Headroom;
The height of the load receiving area from the parking level of the crane.
Load height characteristics without attachments
Required working radius;
Height of the lifted (moved) load;
Height of the load-handling device;
Cargo weight;
Installation height of the crane manipulator from the ground (road surface);
Lifting height;
CMU installation level;
Loading platform level
Figure 5 - Binding the crane
3.3. Selection construction hoist.
3.3.1. The selection of a construction lift is made according to two main parameters: load capacity and lifting height. Freight lifts equipped with load-handling devices (monorail, jib, etc.), in addition - by reach.
3.3.2. The lifting capacity of a construction hoist is the mass of cargo and (or) people that the load-carrying device (cabin, loading platform, monorail, jib, etc.) and the hoist as a whole are designed to lift.
The lifting capacity of a construction hoist is determined by its passport.
The lifting capacity of a construction hoist () must be greater than or equal to the weight of the load being lifted, i.e.
3.3.3. The lifting height is determined by the vertical distance from the lift parking level to the load-carrying device in the upper position:
When lifting cargo and (or) people in the cabin, on a platform or in a cradle - to the floor level of the load-carrying device;
When lifting a load on a load-handling device - up to the supporting surface of the hook.
The required lifting height (), determined depending on the construction conditions and the type of construction lift, as shown in Figure 6, must be less than or equal to the lifting height of the construction lift () specified in its passport, i.e.
b) , m), established by passport construction lift, i.e.
The type and brand of lifting machine necessary to ensure the construction (installation) of the facility, indicating its brief technical characteristics, justification for the height of the hook, reach and lifting capacity;
A list of necessary lifting devices (slings, pincers, grips, traverses, containers, containers, etc.) indicating the type, quantity and lifting capacity;
Scaffolds, racks, platforms, cassettes, pyramids necessary for carrying out work and receiving cargo;
Equipment that provides temporary fastening of elements before their unfastening;
A list (by weight) of building parts and structures indicating the boom radii on which they will be laid (mounted);
Availability and placement of warning signs and posters;
Methods (schemes) of slinging, ensuring the supply of elements during storage and installation in a position corresponding to or close to the design one and their locations;
Installation locations and power of lighting devices;
Locations and parameters air lines power transmission;
Structures and devices of the crane base for the installation of jib cranes (application reinforced concrete slabs and etc.);
Location and design of crane rail fencing;
Project for the installation of crane tracks, made in accordance with GOST R 51248-99;
Safe installation of cranes near slopes, pits (trenches), buildings and structures under construction.