Choose a mounting crane according to its characteristics. III
The feasibility of erecting building structures with one or another crane is established according to the installation flow diagram, taking into account the lifting of the maximum possible number of mounted structures from one parking lot with a minimum number of crane permutations.
When choosing a crane, first determine the path of movement along construction site and places of his parking.
Mounted structures are characterized by the mounting mass, mounting height and the required reach. For the installation of the heaviest elements of the building frame, self-propelled jib cranes are used. The choice of a mounting crane is made by finding three main characteristics: the required hook lifting height, lifting capacity and boom reach.
The choice of the crane was made on the basis of design schemes for installation, taking into account the dimensions of the building and maximum weight mounted elements - metal beams, weighing up to 1.35 tons.
For execution construction works mobile jib crane selected. The scheme of parameters for choosing a mounting jib crane is shown in Figure 3.1.
For truck-mounted cranes, the required maximum lifting capacity, hook lifting height and boom reach are determined.
Required lifting capacity of the crane: Q \u003d q 1 + q 2 \u003d 1.35 + 0.15 \u003d 1.505t,
where q 1 - the maximum mass of the lifted load, t;
q 2 - the mass of the traverse or other slinging device, i.e.
We accept Q = 1.5t.
Hook lifting height:
H tr hook \u003d h mount + h zap + h e + h str \u003d 12.4 + 1 + 0.5 + 3 \u003d 16.9 m,
where h mont = 12.4 m - the excess of the mounting horizon above the level of the crane parking;
h zap - stock height - minimum distance between the mounting level and the bottom of the mounted element (at least 0.5 m), m;
h e - height (or thickness) of the element in the mounting position, m;
h str - the height of the slinging in the working position from the top of the mounted element to the crane hook (laying of slings from 1:1 to 1:2, height within 1 ... 4m), m.
Figure 3.1- Scheme of parameters for selecting a mounting jib crane
Triangle ABC is similar to triangle A 1 B 1 C:
AB \u003d b + c / 2; b = 0.5...2.0 m; c \u003d 1/2 beam width \u003d 0.2 m;
AB \u003d 2 + 0.1 \u003d 2.1 m
BC \u003d h str + h floor;
h str \u003d 1 ... 3 m; h floor = 1.5m (in the contracted position);
BC \u003d 3 + 1.5 \u003d 4.5 m
B 1 C \u003d BC + h zap + h e + h mont - h ball;
h ball = 1.0...1.5 m; h mont =12.4m
B 1 C \u003d 4.5 + 1 + 0.5 + 12.4-1.5 \u003d 16.9 m
Required reach:
L \u003d L 0 + a, L \u003d 9 + 1 \u003d 10m
where, a = 0.5..1.0 m.
\u003d (2.1 × 16.9) / 4.5 \u003d 8.89 m.
Hook lifting height: H cr \u003d B 1 C + d-h floor \u003d 16.9 + 1.5-1.5 \u003d 16.9 m
Required boom length: L c \u003d 19.64 m
According to the calculated technical parameters, the KS-55713-6K jib pneumatic wheel truck crane was selected.
Crane specifications:
boom length 21 m;
load capacity 1.2 ... 25 t;
lifting height at max Q 9 m;
boom reach 20 ... 3 m.
Figure 3.2 - Load-altitude characteristics of the truck crane KS-55713-6K
The choice of the right truck crane for the installation of structures, at the stage of drawing up a construction organization project, largely determines the further sequential chain of work.
If it is known that the existing dimensions of the structure do not allow the use of lifting mechanisms that are available or that can be rented in the region at a reasonable price, then the technology for performing work changes.
In any case, a person who is engaged in solving a similar problem - meaning the choice of a lifting mechanism - should have the necessary information at hand:
Cargo characteristics of cranes;
- dimensions of the building - length, height, width;
- the possibility of dividing the building into separate blocks.
Based on the available information, a decision is made on the use of the type of lifting mechanism - this can be:
Gantry or gantry cranes;
- tower cranes;
- self-propelled cranes on wheeled or caterpillar tracks;
- automobile cranes.
In addition to the type of crane, the possibility of using cranes with various types booms (meaning self-propelled and truck cranes) - such as:
Simple lattice boom;
- a simple lattice arrow with inserts;
- a simple lattice boom with a "jib";
- telescopic arrows.
Often, when it becomes necessary to perform installation in buildings with significant dimensions in terms of and not great height - truck cranes and self-propelled cranes are used - installation is carried out from inside the building - “on oneself”. Those. a self-propelled crane is located inside the building - it mounts structures around itself and gradually, at the exit outside the building, closes the gripper by mounting floor slabs and wall fencing - thereby closing the installation opening.
For long and tall buildings, it is more convenient to use a tower crane.
For underground structures of small width, gantry or portal cranes are better suited.
Today, with the advent of a large number high-performance truck cranes, high load capacity and long outreach - the choice of this type of cranes has become more relevant due to their lower cost. The types of tasks that are successfully solved with the help of truck cranes are really multifaceted: truck cranes are used for construction and installation, loading and unloading, etc. That's why, right choice work is a top priority.
So we decide, in our choice of a mobile crane (including an automobile one):
Crane lifting capacity - determined by the weight and dimensions of the heaviest building structure - with a minimum and maximum reach of the boom;
Crane boom length - boom reach - boom type - whether the truck crane can lift the load;
Are they safe design characteristics truck crane - to ensure necessary conditions security;
The basic dimensions of the crane - will the machine itself and its working bodies be able to move freely within working area and most importantly safe;
Well, to complete the picture, it is necessary to have a plan and sections of the building, as well as a plan of the construction site as part of the working draft.
According to their characteristics, truck cranes can have different dimensions, load capacity (6 - 160 tons) and boom length.
The boom is the most important part of the truck crane. The length, reach of the boom, the design capabilities of the truck crane determine the possibility of working at different heights, with different designs. The reach of the boom is calculated as the distance from the axis of the turntable to the center of the hook mouth. That is, it is the projection of the length of the crane boom on the horizontal axis. This can be a distance of 4 to 48 meters. The design of the boom consists of several sections, which allows you to work on different heights. Today, telescopic booms based on three sections are in demand - they are quite compact, but at the same time they provide lifting of cargo to a great height. "Gusek" is currently used quite rarely.
So, first of all, we determine the places of possible parking of the truck crane - we put the parking points on the plan (drawing) of the construction site, near the place of the proposed installation;
We draw concentric circles from the center of the turntable on the same site plan - smaller (this is the minimum reach of the boom) and large (this is the maximum reach of the boom) and look at what we have in the "danger zone". The "danger zone" is the area between the larger and smaller circles;
We draw attention to the presence in the danger zone of parts of buildings and structures, power lines, open ditches and pits;
We take into account the possibility of supplying technological transport to the installation area - panel carriers, etc.
Picture 1.
We take graphical information on the load characteristic of the crane and a section of the building. On the section of the building, we mark the point of possible parking of the crane and the height of the turntable. From the obtained point on the scale with a ruler, we set aside the maximum length of the boom, which will provide the load capacity we need. The load capacity of a 75 ton truck crane with a maximum reach of the boom can be only 0.5 tons. Do not forget to take into account the safe length of the slings (no more than 90 degrees between the slings) and the safe distance from the boom to the protruding building structures of at least 1 m.
Figure 2.
If we get the required parameters, that is, we can mount the desired structure in right place- then we stop there. If the experiment fails, we change parking places. If this does not help, then we change the tap. Miracles do not happen - the problem clearly has a solution.
As a selection option (if you have a load characteristic on a scale) - cut out (on the same scale) - a square of paper according to the size of the section of the building and begin to move it along the load characteristic diagram, achieving optimal compliance.
3.18. Payment technical parameters for mobile crane selection.
To select the required crane, you should calculate the lifting capacity (Q), the height of the hook (H k), the hook reach (L k) and the length of the boom (l page)
Calculation of load capacity (Q). Q = q + q page + q nav , T; q is the weight of the mounted element, t
q we calculate for all montir. elements. We enter the calculations in the table.
Hook lifting height (H to ).
a) for columns H to = a + h uh + h page + h p
a - height of the mounting overlift, 0.5 ... 1 m
h e - the height of the mount. element
h str - slinging height
h p - reserve height, 1 ... 1.5 m
b) when lifting the structure onto the underlying elements. H to = h 0 + a + h uh + h page + h p
h 0 - the height of the underlying structure or mark on which the element is mounted.
3.19. Calculation of technical parameters for the selection of a tower crane.
Tower cranes are used with a large volume of mounted structures, with a building height of over 20m. Crane tracks should be arranged outside the soil punching pyramid. Depending on the width of the building to be erected, the cranes can be located on one side.
Tower cranes are divided by design
1. Tower cranes with fixed boom.
R to =L to =l str ≥ a1 + B;
a1 \u003d B to + b / 2 + 0.7
2. Tower cranes with a rotary boom
l str \u003d √ (L to -C to) 2 + (H to -h w +h floor) 2
R \u003d L k \u003d a1 + B; R – crane range.
h w - hinge height
h p - pulley height
H to - hook lifting height
a1 is the distance from the building to the middle of the crane runways.
B-width of a building or structure
L to - hook reach (horizontal projection of the boom)
Sk-distance from the hinge of the boom to the center of the crane runway
Lc - boom length
R to - the radius of the crane.
Calculation of load capacity(Q). Q \u003d q + q str + q nav, t; q is the weight of the mounted element, t
q str - weight of slinging equipment, t
q nav - the weight of hinged ladders or cradles, t
q we calculate for all montir. elements.
Hook outreach calculation (L to ) with a free choice of working positions.
L to – horizontal projection of the crane boom at the time of installation of the structure in the design position. During installation, lifting of the crane parking lot can be free, fixed, rationally selected (providing installation or lifting of several structures from one parking lot).
Free installation of the crane: L to \u003d √ (a 2 + b 2); l str \u003d √ L to 2 + (N to -h w +h floor) 2
Calculation of the hook reach and the length of the crane boom according to the optimal angle of the boom.
The calculation is carried out according to a fixed angle of inclination. We accept such a scheme when lifting heavy structures (beams, crossbars) or when the structure is remote from the parking lot (slabs)
Optimum tilt angle 60 ... 70 o
tgα C \u003d (N to -h W + h p) / (L to - C to)
L k \u003d (N k -h W + h p) / (tgα C) + C k
l str \u003d (L to - C to) / cosα C \u003d (H to -h W + h p) / sinα C
3.22. Crane selection method according to design parameters.
To select a crane, you need to know the following technical characteristics:
carrying capacity Q, t
hook lifting height Hk, m
hook reach L, m
boom length lstr, m
Q = q bunker + q lines + q concrete, t;
Hk \u003d h bet + h hands + h bunker + h fear + h chain hoist
L to - horizontal projection of the crane boom at the working moment or at the time of concrete placement. Determined based on the dimensions in the building and in the plan. It is advisable to lay concrete at least 2 cups from the 1st crane station. With a span of 12m, 4 foundations can be concreted from 1 parking lot.
L k \u003d √ (a 2 + b 2);
l str \u003d √L to 2 + (N to - h w + h floor) 2
Using a similar technique, we calculate the technical characteristics for all mounted elements.
The selection of cranes is performed in the following sequence:
a) According to the max value of the boom length, we determine the necessary crane and its brand from the reference book.
lfac≥lcalc
b) According to the reference book, page cranes, we select the schedule for changing the technical. har-to, the argument is the departure of the hook.
c) Knowing the hook reach, we determine the actual value according to the schedule. lifting capacity and lifting height of the hook.
d) Fact. characteristics of the selected crane must be at least calculated.
Calculation of the shifting operational performance of the assembly crane (P uh ).
Crane productivity - the amount of cargo lifted per shift.
When lifting elements or loads of the same type
P e \u003d (Qt cm 60k g k in) / t c, t / cm or m 3 / cm
Q - the calculated value of the crane capacity, m 3 or t.
k g - coefficient of use of the crane in terms of load capacity, k g ≤ 1 \u003d Q calculated / Q actual
k in - the coefficient of use of the crane in time:
For tower cranes - 0.9
For crawler cranes - 0.85
For mobile cranes - 0.8
t c - cycle time
t c \u003d t manual + t machine, min
t manual = H in 60/R, min
R is the number of people or the standard number of installers in the link, YeniR (4-1)
t machine \u003d N in / V lifting + N to / V lowering + 2αn about k joint / 360 + S / V horizontal
S - distance m / y with crane stands (m), per 1 mounted element.
V mountains - travel speed (m / min)
H to - hook lifting height, m
α is the angle of rotation of the crane boom from the place of slinging to the place of installation.
V lifting - boom lifting speed (m / min)
n R - angular speed of rotation of the crane, rpm
V lowering - boom lowering speed (m / min)
k joint - the coefficient of alignment of the crane operation when turning, depends on α (for α ≤ 45 o, k c = 1; α > 45 o, k c = 0.9)
Average operating performance of the crane.
Distinguish performance when performing certain types of work, it is called element-by-element. Having calculated the installation performance of each element Pe1, Pe2, ... Pek, it is possible to calculate the average performance:
P exp average = (n1 q1) P e1 /(Σq i n i ) + (n2 q2) P e2 /(Σq i n i ) +… + (n i q 1 ) P uh i /(Σq i n i ), [t/cm],
where Σ q i n i – the total weight of the structure of the entire building, of all types of elements.
Occupational safety at urban construction and economy when using cranes and hoists.
Educational-methodical, practical and reference manual.
Authors: Roitman V.M., Umnyakova N.P., Chernysheva O.I.
Moscow 2005
1. OCCUPATIONAL HAZARDS WHEN USING CRANES AND LIFTS.
1.1. The concept of industrial hazard.
1.2. Dangerous zones at the construction site.
1.3. Examples of characteristic accidents and accidents associated with the use of cranes and hoists.
1.4. The main causes of accidents and accidents when using cranes and hoists.
2. GENERAL ISSUES OF LABOR SAFETY WHEN USING CRANES AND LIFTS.
2.1. General condition for ensuring labor safety.
2.2. Regulatory bases for ensuring labor safety when using cranes and hoists.
2.3. The main tasks of ensuring labor safety when using cranes and hoists.
3. ENSURING WORK SAFETY WHEN USING CRANES AND LIFTS.
3.1. Selection of cranes and their safe binding.
3.1.1. Crane selection.
3.1.2. Cross-linking of cranes.
3.1.3. Longitudinal binding of tower cranes.
3.2. Determination of the boundaries of hazardous areas of operation of cranes and hoists.
3.3. Ensuring labor safety in hazardous areas of cranes and hoists.
3.3.1. Instruments and safety devices installed on cranes.
3.3.2. Ensuring safety when installing cranes.
3.3.3. Protective grounding of crane tracks.
3.3.4. Ensuring safety in the joint operation of cranes.
3.3.5. Ensuring safety when using lifts.
3.4. Measures to limit the dangerous zone of the crane.
3.4.1. General provisions.
3.4.2. Forced restriction of the crane operation area.
3.4.3. Special Events to limit the hazardous area of the crane.
3.5. Ensuring labor safety when installing cranes near power lines.
3.6. Ensuring labor safety when installing cranes near recesses.
3.7. Ensuring safety in the storage of materials, structures, products and equipment.
3.8. Ensuring safety during loading and unloading operations.
4. SOLUTIONS TO ENSURE LABOR SAFETY IN ORGANIZATIONAL AND TECHNOLOGICAL DOCUMENTATION (PPR, POS, etc.) WHEN USING CRANES AND LIFTS.
4.1 General provisions.
4.2. Stroygenplan.
4.3. Technological schemes.
3.1. Selection of cranes and their safe binding.
3.1.1. Crane selection.
The choice of a crane for the construction of an object is carried out according to three main parameters: lifting capacity, boom reach and load lifting height.
The required lifting capacity of the crane for the construction of a particular facility and the corresponding boom reach is determined by the mass of the heaviest load. The following are taken into account in the mass of the load: the mass of removable load-handling devices (traverse, slings, electromagnets, etc.), the mass of attachments mounted on the mounted structure before it is lifted and structures increase the rigidity of the load during installation.
The actual lifting capacity of the crane Qf must be greater than or equal to the allowable Qdop and is determined from the expression:
Q f \u003d P gr + P zah.pr + P nav.pr + P us.pr ≥ Q add (3.1)
P gr- the mass of the lifted load;P input- weight of the lifting device;
P nav.– mass of mounted mounting devices;
P us.pr- the mass of the reinforcement of the element being lifted during the installation process.
The reach of the boom and the required lifting height of the load is set depending on the mass of the heaviest and most remote structure, taking into account the width and height of the building.
The required lifting height H gr is determined from the crane installation mark by adding the following indicators vertically (Fig. 3.1.):
- the distance between the crane parking mark and the zero mark of the building (±h st.cr);
- the height of the job from the zero mark to the upper mounting horizon h zd ;
- a margin of height equal to 2.3 m, from the conditions of safe work on the upper mounting horizon (h without = 2.3 m);
- the maximum height of the transported cargo, taking into account the devices attached to it - h gr;
- height of the lifting device h zah.pr ;
H gr = (h zd ± h st.cr ) + h without + h gr + h zah.pr , (m) (3.2)
In addition, to ensure the safety of work in these conditions, it is necessary that the distance from the counterweight console or from the counterweight located under the tower crane console to the platforms where people can be is at least 2 m.
When choosing a crane with a lifting boom, it is necessary that a distance of at least 0.5 m be observed from the boom dimension to the protruding parts of buildings, and at least 2 m vertically to the covering (overlapping) of the building and other sites where people can be (Fig. 3.2). If the crane boom has a safety rope, the indicated distances are taken from the rope.
Fig.3.2. Ensuring labor safety when using cranes with a lifting boom for the installation of elements of upper facilities under construction (reconstruction).
The main parameters of a self-propelled jib crane are: lifting capacity, hook lifting height, boom reach, boom length.
1. Determine the lifting capacity of the crane(), T:
Where is the mass of the element, t; - mass of load-handling devices, t; - weight of the rigging installation, t;
10+0,28+0=10,28
2. Determine the height of the hook()m:
Where is the lifting height of the crane hook, m; - distance from the level of the tap outlet to the support of the mounted element, m; – height margin required to move the element above the previously installed ones, m, is assumed to be at least 0.5 m; – height (thickness) of the element in the lifting position, m; – height of load-handling devices, m; - the height of the chain hoist in the tightened position (1.5 - 5 m).
0+0,5+0,4+1,2=2,1
3. Determine the height of the boom:
Where - the height of the boom;
4. Determine the reach of the arrow ( ):
= 
,
Where e is half the thickness of the boom at the level of the top of the mounted element or the previously mounted structure (1.5 m); c - the minimum gap between the boom and the mounted element (0.5-1 m); d is the distance from the center of gravity to the edge of the element closest to the boom; a - half of the crane base (approximately 1.5 m;); Нstr - boom lifting height, m; hsh - distance from the level of the crane parking to the axis of rotation of the boom, m.
= 
=2,5
Required arrow length(L str) is determined by the formula:
L str = 
L str \u003d \u003d 2.3
where is the height of the boom, m; - distance from the level of the crane parking to the axis of rotation of the boom, m;
Calculation of crane parameters for the installation of beams and trusses. The required lifting capacity of the crane (Q cr) is determined by the formula (1).
The height of the hook (H kr) is determined by the formula (2).
The required reach of the boom (l str) is determined by the formula (3).
The length of the arrow (L str) is determined by the formula (5).
Q cr \u003d q el + q gr + q main \u003d 1.75 + 9.8 + 0 \u003d 1.55 t.
N cr \u003d h o + h s + h el + h gr \u003d 8.4 + 1 + 3.3 + 3.6 \u003d 16.3 m;
N str \u003d N cr + h p \u003d 16.3 + 2 \u003d 18.3 m.
l str = 
= l str = 
= 4.2 m.
5. Determine the length of the arrow:
L str = = = 17.0 m.
Calculation of crane parameters for the installation of crane beams
1. Determine the load capacity:
Q cr \u003d q el + q gr + q main \u003d 4.5 + 0.9 + 5.2 \u003d 10.64 t.
2. Determine the height of the hook:
N cr \u003d h o + h s + h el + h gr \u003d 0 + 0.5 + 0.9 + 3.2 \u003d 4.6 m;
3. Determine the height of the boom:
N str \u003d N cr + h p \u003d 18.4 + 2 \u003d 20.4 m.
4. Determine the required boom reach:
l str = = l str = 
+1.5= 2.7 m.
5.N str \u003d N cr + h p \u003d 4.6 + 1.5 \u003d 6.1 m.
6. Determine the length of the arrow:
L str = = = 4.7 m.
Scheme for determining the installation characteristics of the crane during the installation of beams (trusses) of the coating.
Scheme for determining the installation characteristics of the crane during the installation of beams (trusses) of the coating
Calculation of crane parameters for the installation of floor slabs. The required lifting capacity of the crane (Q cr) is determined by the formula (1).
The hook lifting height (H kr) is determined by the formula (2)., h o for the coating slab is determined by the formula h o \u003d h 1 + h 2, where h 1 is the height of the column from the crane parking level; h 2 - deduction of a beam (truss), m.
The height of the boom (H str) is determined by the formula (4).
Minimum Required boom reach(l str) is determined by formula (3).
Scheme for determining the installation characteristics of the crane during the installation of roof slabs.
The required boom reach for mounting the end plate is determined by the formula:
l str \u003d l 2 str. min +,
where is the span of the building, m; – width of the slab, m.
Arrow length(L str) is determined by the formula (5).
1. Determine the load capacity:
Q cr \u003d q el + q gr + q main \u003d 3.31 + 5.7 + 0 \u003d 9.01 t.
2. Determine the height of the hook:
h o \u003d 8.4 + 3.3 \u003d 11.7 m.
N cr \u003d h o + h s + h el + h gr \u003d 11.7 + 0.5 + 4.5 + 3.31 \u003d 20.01 m;
5.8 \u003d 6.4 (h 2) - 0.7 (deepening of the column in the glass).
3. Determine the height of the boom:
N str \u003d N cr + h p \u003d 20.01 + 2 \u003d 22.01 m.
4. Determine the required boom reach:
l str = = l str = 
= 15.4 m.
5. Determine the required boom reach for mounting the end plates:
l str = 
= 15.8 m.
6. Determine the length of the arrow:
L str = = = 15.8 m.
According to certain required parameters of load capacity, hook lifting height, boom reach, boom length, boom reach, boom length, two cranes are selected from reference sources, the characteristics of which correspond to the required ones or exceed them (by no more than 20%).
A crane is selected as a result of comparing the parameters that are presented in table.
In addition, it is advisable to perform an economic comparison of preferred cranes, comparing the cost of machine shifts. With the same cost of machine shifts, cranes with lower engine power and other more favorable indicators are preferable.
Output. Taking into account the required technical parameters, we select the MGK16 crane.
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