CN113006588A - Inverted construction method of chimney platform - Google Patents
Inverted construction method of chimney platform Download PDFInfo
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- CN113006588A CN113006588A CN202110180952.6A CN202110180952A CN113006588A CN 113006588 A CN113006588 A CN 113006588A CN 202110180952 A CN202110180952 A CN 202110180952A CN 113006588 A CN113006588 A CN 113006588A
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- platform
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- lifting platform
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- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04H—BUILDINGS OR LIKE STRUCTURES FOR PARTICULAR PURPOSES; SWIMMING OR SPLASH BATHS OR POOLS; MASTS; FENCING; TENTS OR CANOPIES, IN GENERAL
- E04H12/00—Towers; Masts or poles; Chimney stacks; Water-towers; Methods of erecting such structures
- E04H12/34—Arrangements for erecting or lowering towers, masts, poles, chimney stacks, or the like
- E04H12/344—Arrangements for lifting tower sections for placing additional sections under them
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- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04G—SCAFFOLDING; FORMS; SHUTTERING; BUILDING IMPLEMENTS OR AIDS, OR THEIR USE; HANDLING BUILDING MATERIALS ON THE SITE; REPAIRING, BREAKING-UP OR OTHER WORK ON EXISTING BUILDINGS
- E04G3/00—Scaffolds essentially supported by building constructions, e.g. adjustable in height
- E04G3/28—Mobile scaffolds; Scaffolds with mobile platforms
- E04G3/30—Mobile scaffolds; Scaffolds with mobile platforms suspended by flexible supporting elements, e.g. cables
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- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04G—SCAFFOLDING; FORMS; SHUTTERING; BUILDING IMPLEMENTS OR AIDS, OR THEIR USE; HANDLING BUILDING MATERIALS ON THE SITE; REPAIRING, BREAKING-UP OR OTHER WORK ON EXISTING BUILDINGS
- E04G3/00—Scaffolds essentially supported by building constructions, e.g. adjustable in height
- E04G3/28—Mobile scaffolds; Scaffolds with mobile platforms
- E04G3/30—Mobile scaffolds; Scaffolds with mobile platforms suspended by flexible supporting elements, e.g. cables
- E04G3/32—Hoisting devices; Safety devices
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- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04H—BUILDINGS OR LIKE STRUCTURES FOR PARTICULAR PURPOSES; SWIMMING OR SPLASH BATHS OR POOLS; MASTS; FENCING; TENTS OR CANOPIES, IN GENERAL
- E04H12/00—Towers; Masts or poles; Chimney stacks; Water-towers; Methods of erecting such structures
- E04H12/28—Chimney stacks, e.g. free-standing, or similar ducts
Abstract
The invention provides a chimney platform inverted construction method, which belongs to the technical field of building construction, and is characterized in that a lifting platform is built in advance, a prefabricated top platform component is lifted to a top platform mounting position by the lifting platform, and the lifting platform and a concrete cylinder wall are temporarily locked by a chain block; chiseling out an embedded part of the top platform on the outer cylinder wall of the concrete according to the elevation of a horizontal beam of the top platform, and welding a cross beam corresponding to the top platform at a set position; erecting a tripod on a lifting platform, and sequentially hoisting and installing a top platform component, a top inclined support, a top arc channel steel truss, a top grid plate and a top railing by using a chain block; after the top platform is installed, sequentially installing a middle platform and a bottom platform; the invention realizes the construction of the chimney platform from top to bottom, and has the technical effects of low construction cost and short construction period.
Description
Technical Field
The invention relates to the technical field of building construction, in particular to a chimney platform inverted construction method.
Background
Generally, a self-supporting chimney and other high-rise buildings are installed in a sectional hoisting mode by using large machinery as hoisting equipment to build a steel platform, and the building process is from bottom to top. The existing platform building technology has the following disadvantages:
1. large machinery is used as lifting equipment, and the investment is high;
2. the construction period is longer due to the construction and later-stage disassembly of the lifting equipment;
3. the higher the height of the lifting device, the worse the safety.
Therefore, a chimney platform construction method which is simple, convenient and fast and has high construction efficiency is urgently needed.
Disclosure of Invention
The invention aims to provide a chimney platform inverted construction method, which is used for carrying out platform installation construction from top to bottom by installing a lifting platform, so that the platform installation construction is realized quickly and safely.
In order to achieve the purpose, the invention provides a chimney platform inverted construction method, which comprises the following steps:
s1, a lifting platform is set up in advance, the prefabricated top platform component is lifted to the mounting position of the top platform by the lifting platform, and the lifting platform and the concrete cylinder wall are temporarily locked by a chain block; chiseling out an embedded part of the top platform on the outer cylinder wall of the concrete according to the elevation of a horizontal beam of the top platform, and welding a cross beam corresponding to the top platform at a set position;
s2, erecting a tripod on the lifting platform, sequentially hoisting a top layer inclined support, a top layer arc-shaped channel steel truss, a top layer grid plate and a top layer railing by using a chain block, and sequentially welding a top layer platform member, the top layer inclined support, the top layer arc-shaped channel steel truss, the top layer grid plate and the top layer railing to complete the installation of the top layer platform;
s3, lifting the prefabricated middle layer platform component to the mounting position of the middle layer platform by using the lifting platform, and welding the middle layer platform component to complete the middle layer platform mounting;
and S4, lifting the prefabricated bottom platform component to the mounting position of the bottom platform by using the lifting platform, and welding the bottom platform component to complete the mounting of the bottom platform.
Further, preferably, in step S2, after the top platform is installed, the vertical ladder at the lower part of the top platform is hoisted by using a chain block;
the vertical ladder is vertically vertical by using a hanging wire taper method, and the vertical ladder support is welded with the prefabricated part of the corresponding chimney cylinder wall.
Further, preferably, the building method of the lifting platform comprises the following steps:
s11, after the reinforced concrete outer cylinder of the chimney is capped, lifting the support top beam by using the scaffold lifting device;
s12, lifting the support top beam to the scaffold lifting platform by sections by using a small lifting lever, assembling and welding to complete the installation of the support top beam; wherein, the supporting top beam is installed along the flue direction;
s13, sequentially mounting a pulley block and a winch on the support top beam;
and S14, mounting a lifting platform on the support sky beam.
Further, preferably, the supporting roof beam is provided with a falling-preventing rope.
Further, preferably, the supporting roof beam is welded with an embedded part of the outer cylinder wall of the chimney; the supporting roof beam comprises two steel beams and a cross beam arranged between the two steel beams.
Further, in step S14, preferably, the method for installing a lifting platform on the supporting sky beam includes:
lifting the prefabricated single-piece truss and the central cylinder to a position to be installed from the chimney;
assembling the single-piece truss and the central cylinder to form a lifting platform;
taking the center of the lifting platform as the center of a circle and the radius of the central cylinder as the radius area as the central body of the lifting platform; taking the area outside the central body of the lifting platform as a lifting platform radiator; laying a steel plate in the radiator;
and connecting the lifting lug of the lifting platform with the lifting hook through a steel pin shaft.
Further, preferably, before the lifting platform is used, the method further comprises a step of performing a load test on the lifting platform, and the method comprises the following steps:
loading 4.5 tons of materials on a lifting platform, and standing for 30 minutes at a height of 50 cm from the ground;
loading 4.95 tons of materials on a lifting platform, and standing for 30 minutes at a height of 50 cm from the ground;
loading 4.95 tons of materials on a lifting platform, and carrying out 5 rounds up and down within a range of 3 meters away from the ground;
and if the lifting platform has no welded junction cracks and the steel wire rope clamp is loosened, judging that the load test of the lifting platform is qualified.
Further, preferably, the single truss is formed by welding double-spliced angle steel of less than 63; rolled steel plate with central cylinder of 〥 -14 mm in diameter
The steel cylinder of (1).
Further, preferably, after the steel plate is laid in the radiation body, the method further comprises: a movable railing is arranged on the lifting platform.
As described above, the chimney platform inverted construction method provided by the invention has the following beneficial effects that the lifting platform is built and then constructed from top to bottom:
1. compared with the lifting equipment of large machinery, the total weight of the lifting platform is only 4 tons, and the lifting platform has the characteristics of simplicity, portability and short construction period;
2. the vertical ladder component and the platform component are prefabricated, and the size of the component manufactured after solid lofting is accurate, so that the mounting quality is further improved;
3. the cost of the lifting equipment is low, and the popularization is easy;
4. the construction of the platform is carried out from top to bottom by building the lifting platform, so that the construction period is greatly shortened;
5. the lifting platform is subjected to load testing, and the construction safety is guaranteed.
To the accomplishment of the foregoing and related ends, one or more aspects of the invention comprise the features hereinafter fully described and particularly pointed out in the claims. The following description and the annexed drawings set forth in detail certain illustrative aspects of the invention. These aspects are indicative, however, of but a few of the various ways in which the principles of the invention may be employed. Further, the present invention is intended to include all such aspects and their equivalents.
Drawings
Other objects and results of the present invention will become more apparent and more readily appreciated as the same becomes better understood by reference to the following description and appended claims, taken in conjunction with the accompanying drawings. In the drawings:
FIG. 1 is a schematic view of a scenario of a chimney platform inversion construction method according to an embodiment of the invention;
FIG. 2 is a schematic structural view of a lift platform according to an embodiment of the present invention;
FIG. 3 is another schematic illustration of the lifting platform of one embodiment of the present invention;
wherein the content of the first and second substances,
1. supporting the top beam; 2. a fixed pulley; 3. lifting the platform; 31. a truss of the central body; 32. a central barrel; 33. a truss of radiators; 34. lifting lugs; 4. the wall of the chimney; 5. a movable pulley; 6. a railing.
Detailed Description
In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of one or more embodiments. It may be evident, however, that such embodiment(s) may be practiced without these specific details.
According to the chimney platform inverted construction method, the lifting platform is installed, the platform is installed and constructed from top to bottom, and the technical effect of quickly and safely installing the platform is achieved.
Various embodiments of the present invention will be described in detail below with reference to the accompanying drawings.
Fig. 1 illustrates a scenario of a chimney platform inversion construction method as a whole. Specifically, fig. 1 is a scene schematic diagram of a chimney platform inverted construction method according to an embodiment of the present invention; as shown in figure 1 of the drawings, in which,
the invention provides a chimney platform inverted construction method, which comprises the following steps: steps S1-S4.
S1, pre-building a lifting platform 3, lifting the prefabricated top platform component to a top platform mounting position by using the lifting platform 3, and temporarily locking the lifting platform and the concrete cylinder wall by using a chain block; and chiseling out the embedded part of the top platform on the outer cylinder wall of the concrete according to the elevation of the horizontal beam of the top platform, and welding the cross beam corresponding to the top platform at a set position.
In a specific implementation process, lofting and blanking are performed before the lifting platform is installed. Lofting and blanking are required for prefabrication of the lifting platform or each platform component. The construction team amplifies the samples according to the drawing 1:1, checks the drawing size and cuts node blanking templates according to the drawing, the design description and the relevant standards; the node blanking sample plate is inspected and approved by a quality inspector and then prefabricated.
And in the prefabricating process, the platform steel beams in each platform component are prefabricated one by one according to a design drawing, wherein the H-shaped steel beam of each layer of platform is lengthened by 100mm according to the drawing, and after actual data of the wall deviation of the concrete cylinder is obtained to be measured, secondary cutting is carried out before installation so as to compensate for the construction error of the cylinder wall. When blanking of the H-shaped steel beam is performed by semi-automatic cutting and splicing of flanges and webs, the joint position should be within the range of the span from the support 1/3, and the splicing seams of the H-shaped steel beam and the support 1/3 should be staggered by 150 mm. The technical requirements are in accordance with the requirements of the welding H-shaped steel standard.
Furthermore, in order to avoid the problem that the H-shaped steel beam is easy to generate angular deformation and longitudinal distortion of the wing plate, a reverse deformation method, a rigid fixing method, a reasonable welding sequence, welding parameters and other technological measures are adopted when the H-shaped steel beam is assembled and welded to prevent the generation of the angular deformation and the distortion phenomenon. Specifically, the construction standard is that the corrected steel surface should not have obvious concave surfaces and damages, and the surface scratch depth should not be more than 0.5 mm. Wherein, the local deflection rise f of the steel plate after steel correction is as follows: the web delta is less than or equal to 14mm, and f is 1/1000 and not more than 1.5 mm. The bending rise f of the angle steel, the channel steel and the I-shaped steel in the prefabricated part is L/1000 and is not more than 1.5 mm; the non-perpendicularity of the cutting section and the surface of the steel is not more than 10% of the thickness of the steel and not more than 2.0 mm; the cut surface of the plate must not have cracks, delamination and defects larger than 1.0 mm.
Specifically, the lifting platform system comprises a supporting top beam 1, a pulley block, 2 winches with 5t, a lifting platform 3 and the like. The principle of the system is similar to that of a portal lifting frame system, and the vertical transportation of steel, personnel, machines and tools used for construction and the like in the steel platform construction is born; the lifting platform system is provided with a support top beam as a stressed beam for vertical transportation, and the stressed beam transmits force to the reinforced concrete outer cylinder wall. The pulley block comprises a fixed pulley 2 and a movable pulley 5.
The lifting equipment is simple, portable, practical and easy to operate, the total weight of the lifting platform is only 4t, the lifting is easy, the speed is high, and the construction period is shortened; secondly, construction is carried out from top to bottom, the upper part and the lower part are smooth without obstruction, and the construction period is further shortened, so that the actual construction period is shortened by 30 percent compared with the original planned construction period; thirdly, the investment of the lifting equipment is low, the cost is saved, the economic benefit is improved, and the cost is saved by 50 percent compared with the cost of purchasing a whole set of forming lifting platform equipment only by a self-made lifting platform system.
The construction method of the lifting platform comprises the following steps:
and S11, after the reinforced concrete outer cylinder body of the chimney is capped, lifting the support top beam 1 by using the scaffold lifting device.
The supporting top beam 1 is a horizontal component which directly bears external force caused by vertical transportation, and vertical transportation can be completed by arranging the fixed pulley block 2 on the supporting top beam and additionally arranging the winch, the lifting lock, the lifting platform 3, the electrical equipment and the like.
In a specific embodiment, the supporting sky beams are welded with embedded parts of the chimney wall 4; the supporting roof beam comprises two steel beams and a cross beam arranged between the two steel beams. Specifically, after the steel beams are placed and fixed in place, the distance between the two beams is adjusted, reinforcing ribs and connecting plates are welded, fixed pulleys are installed, and steel wire ropes are threaded by a 5t winch. The steel beam is made of two H-shaped steels (2H600 multiplied by 200 multiplied by 11 multiplied by 17, Q235B), the total length L is 11.7m, the calculated length L0 is 11.2m, the distance between the two steel beams is 200mm, and steel plates (-20 multiplied by 220 multiplied by 580@1000) are arranged at the upper flange and the lower flange of the steel beam for connection in order to ensure the integral stability; so as to be used as the lateral support of the steel beam and avoid the instability of the single steel beam.
The steel beam is welded on the embedded part at the top of the outer cylinder wall of the chimney, so that the lateral displacement and torsion of the beam at the support can be effectively prevented, and a connecting steel plate is arranged between the two beams to serve as a lateral support. The distance between the connecting steel plates is 1m, namely the length L of a compression flange of the beam is 1000mm, the width b1 of the flange is 200/2 mm which is 100mm, and L/b is 10 < 13.
In order to further ensure the safety of construction, the load value of members such as steel beams needs to be limited during the implementation process. In particular, the first and second (c) substrates,
when the construction platform is designed according to 8.6t (including the self weight of the platform and the weight of a lifting object), the actual value of the load is taken: 21.5KN for F1, 43KN for F2, and 125N/mm for fv2，f＝215N/mm2，E＝206000N/mm3,Ix＝74418.64cm4，S＝1431.58cm3，Wx＝2480.62cm3The weight of the beam is 103 kg/m. Meanwhile, the reinforcing effect of the connecting plate between the two beams is not considered in the calculation.
Beam support reaction force:
RB＝(F2×5.6+F1×0.6)/11.2＝(43×5.6+21.5×0.6)/11.2＝22.7KN。
maximum bending moment in the beam span:
Mmax＝RB×5.6+ql2/8＝22.7×5.6+2.06×11.22/8＝159.4KN·m。
bending normal stress:
δ is 159.4 × 106 × 300/2 × 744186400 is 32.1MPa < f is 215MPa, bending resistance meets the requirement.
Midspan maximum shear force: v86 +2.06 × 11.2 109.1KN
Zeta is VS/Itw is 109100 × 1431580/2 × 744186400 × 11 is 10MPa < fv is 125MPa, and the shearing resistance meets the requirement.
S12, lifting the support top beam 1 to the scaffold lifting platform 3 in sections by using a small lifting lever, assembling and welding to complete the installation of the support top beam 1; wherein, the supporting top beam 1 is installed along the flue direction.
Specifically, after the reinforced concrete outer cylinder is capped, a support beam (spliced by 2H600 multiplied by 200 multiplied by 11 multiplied by 17) is installed by using a scaffold lifting device, the support beam is lifted to a construction scaffold lifting platform of the outer cylinder of the chimney in sections by using a small pulling rod to be assembled and welded, and the support roof beam section meets the condition that the maximum load of the small pulling rod is controlled within 0.8t and is installed along the direction of a flue.
And S13, sequentially mounting a pulley block and a winch on the support top beam 1.
Then, an anti-falling rope is arranged on the supporting top beam. In particular, 4 lengths are placed from the supporting roof beam
The nylon anti-falling rope (the ultimate tension is 2.4t, the use tension is 0.6t, and each rope limits the use of 2 people) so as to ensure the safety of the people in the later construction, and the scaffold lifting system can be detached after the anti-falling rope is installed. The safety design requirement of the nylon anti-falling rope is that the weight of a single person is 80kg, the safety coefficient is 14, and 2 x 80 x 14 is 2240kg and 2400 kg.
The safety design requirements of the pulley are as follows: due to the selection of the steel wire rope
The pulley diameter is 300mm because the pulley curvature requirement is 16 times, and the pulley diameter D is 18 multiplied by 16 is 288 mm.
It should be noted that the power source for lifting and bearing the lifting platform is 2 double-drum 5t windlasses, the windlasses are arranged at the safety position which is 0m outside the layer of the chimney and is not less than 50m away from the root of the chimney, and the steel wire rope is steel wire rope
6X 19+1, 5t for the pulley.
In a specific embodiment, the verification process of the hoisting machine is as follows: the total load P is 86.0KN, the number n of hoisting steel wire ropes is 4, and each steel wire rope winds 3Each pulley has a resistance coefficient E of 1.02, the total resistance coefficient E of a single steel wire rope is E3 of 1.023, and the single steel wire rope is single
The 6 × 19+1 rope load P is 83.76/4 × 1.023 is 22.23KN, and all pulleys are loaded with 50KN under 5 times of safety factor.
Wherein, the factor of safety of pulley: a where (50/22.23) × 5 is 11.25; the minimum breaking force of the phi 18mm 6 multiplied by 19+1 steel wire rope is 146KN, and the safety coefficient of the steel wire rope of the hoisting system is as follows: the A rope is 146/22.23-6.57, so the steel wire rope is safe.
The load of the 5t double-drum winch at 5 times of the safety coefficient is as follows: and the safety factor is as follows, wherein the volume P is 50 multiplied by 2 KN: the winding a is 5 × 50 × 2/(22.23 × 2) ═ 21.55, so the hoist is safe.
2 steel ropes of the ground anchor of the winch are in diameter phi of 36mm (6 multiplied by 37+ 1-1870 MPa), and the traction force of the winch is 8.6/4-2.15 t when the steel ropes form an angle of 300 degrees with the horizontal direction. Then the anchor line is stressed: f2150 × 9.8/2cos300 12.165KN, steel wire rope stress safety factor: the requirement is satisfied when 51 is greater than 6 for 0.82 × 77.3 × 9.8 × 1000/12165. The dead weight of the ground anchor is 1.5 multiplied by 2.5 which is 8.4t, and the stress safety coefficient of the anchoring steel wire rope is as follows: 8.4 is multiplied by 9.8 is multiplied by 1000/12165sin300 is 14 is more than 6, which meets the requirement.
In the vertical steel wire rope guide ground anchor, the anchoring steel wire rope is stressed: f2150 × 9.8, 21.1KN, steel wire rope stress safety factor: 0.82 × 77.3 × 9.8 × 1000/21100 is more than 29, which meets the requirement. The dead weight of the ground anchor (1.5 multiplied by 1.5+2 multiplied by 0.4) multiplied by 2.5 is 12.4t, and the stress safety factor of the anchoring steel wire rope is 12.4 multiplied by 9.8 multiplied by 1000/21100 is 6.0, thus meeting the requirement. Therefore, the minimum safety factor of the power mechanism is 6.0, and the hoisting requirement of 5 times of the safety factor can be met.
And S14, mounting a lifting platform 3 on the support sky beam 1.
Fig. 2 and 3 illustrate the structure of the lifting platform as a whole. Specifically, fig. 2 is a schematic structural diagram of a lifting platform according to an embodiment of the present invention; FIG. 3 is another schematic structural view of a lift platform according to an embodiment of the present invention; as shown in figures 2 and 3 of the drawings,
in a specific embodiment, in step S14, the method for installing the lifting platform 3 on the supporting sky beam 1 includes:
s141, lifting the prefabricated single-piece truss and the central cylinder 32 to a position to be installed from the chimney;
wherein the single truss is formed by welding double-spliced angle steel of less than 63; rolled steel plate with central cylinder of 〥 -14 mm in diameter
The steel cylinder of (1).
Specifically, the lifting platform is an operation platform in the installation process of a chimney steel inner cylinder platform and an escalator. The two-layer about dividing, highly be 1 meter, machines equipment is placed to the lower floor, and the upper strata is placed the construction material, and personnel are under construction at upper platform during the operation. The platform is integrally of a truss structure, and all truss members are formed by welding double-spliced angle steel of less than 63; the central cylinder is made of steel plate with the diameter of 14mm rolled from 〥 ═ 14mm
The steel cylinder of (1); truss manufacturing and lofting on a construction platform to manufacture a moulding bed.
S142, assembling the single truss and the central cylinder to form a lifting platform;
s143, taking the center of the lifting platform 3 as a circle center and taking the radius of the central cylinder 32 as a radius area as a central body of the lifting platform; taking the area outside the central body of the lifting platform as a lifting platform radiator; laying a steel plate in the radiator;
because the diameter of the outer cylinder changes according to the gradient, the lifting platform is divided into a central body and a radiating body. The diameter of the central body is 8.5m, and the maximum diameter of the lifting platform after radiation is about 12.5 m. The lift platform hub is comprised of a lift platform hub truss 31; the lift platform radiator consists of a lift platform radiator truss 33.
After the steel plate is laid in the radiation body, a movable railing 6 is arranged on the lifting platform.
And S144, connecting the lifting lug 34 of the lifting platform with the lifting hook through a steel pin shaft.
In general, firstly, the lifting platform is manufactured on a construction platform outside a chimney, the single-piece truss and the central cylinder are assembled and welded respectively, and then the lifting platform is conveyed into the chimney to be assembled. After the lifting platform framework is combined, the part outside the lifting platform framework, which takes the center of the platform as the circle center and the radius of the inner steel cylinder as the radius, is fully paved by a steel plate with the thickness of 3mm, and movable railings are arranged at the edges. Then, after the whole lifting platform is combined, the lifting hook and the lifting lug of the lifting platform are used
And connecting the 45# steel pin shaft.
In one embodiment, the lifting lug of the platform is machined by a steel plate with the thickness of 30mm (-1020 multiplied by 640 multiplied by 30), the material Q345B is adopted, the safety factor is 1.34, the allowable stress [ delta s ] is 345/1.34 which is 257.5 MPa, the total weight of the platform and the member is considered according to 8.6t, and the size hf of the welding seam is 18 mm.
In addition, the design requirement of the lifting lug of the lifting platform is as follows:
the section value is that A is 30 multiplied by 135 multiplied by 2 is 8010mm2。
Maximum allowable load: and N is 8010 multiplied by 257.5 multiplied by 2062575N, namely the bearing capacity of the lifting lug is 206t > 8.6t, which meets the requirement.
Weld bearing calculation (fillet height Δ ═ 18): the value of the welding seam section is A ═ 18 ÷ 1.414 ÷ 2X 4X 550 ═ 14002mm2(ii) a Maximum allowable load of weld: n14002 × 257.5N 3605515N; namely, the bearing capacity of the welding seam is more than 360t and more than 8.6t, thereby meeting the requirement.
The design requirement on the safety of the pin shaft is that the pin shaft comprises a fixed pulley block pin shaft on the supporting beam and a pin shaft connected with the lifting platform;
d80 is selected as the pin shaft, L is 220mm, the material is 45# steel, and the allowable tensile stress [ Delta s ] is 345/1.5 is 230Mpa according to 1.5 times of safety factor; [ v ] 0.6 [ δ s ] 154.5 Mpa; w ═ pi d3/32, the total weight of the platform and the building block was considered at 8.6 t.
In addition, with the round pin axle that promotes the platform and link to each other:
δ＝M/W＝ql/4W＝8600×9.8×0.17×32/3.14×0.083×4＝71.3MPa＜230Mpa。
V＝8600×9.8/3.14×0.042＝16.8MPa。
the supporting beam fixed pulley block pin shaft and the pin shaft of the pulley block connected with the lifting platform meet the requirements, and the calculation method is the same as the above.
Wherein, the design requirements of fixing the rope head shaft and guiding the fixed pulley on the supporting beam are as follows: the pin shaft is phi 80, L is 500mm, and the other parts are the same as the above, the stress F of the single rope is 8.6 multiplied by 9.8/2 is 42140N, and the single rope can be calculated according to pure shearing:
v is 42140/3.14 multiplied by 0.042 is 8.4Mpa < 154.5Mpa, which meets the requirement.
In a specific embodiment, before the lifting platform is used, the method further comprises the step of carrying out load test on the lifting platform. Assuming that the self weight of the lifting platform is 4.089t, 3t of single loading components are preset, about 0.45t of an electric welding machine 6, about 0.3t of oxygen and acetylene bottles are preset, and the name of a load test to be carried out on the lifting platform of a worker 10 before use is about 0.75t, which is 8.589t in total. The weight of the load test is 110% overload, and a 4.95t weight component needs to be placed on the lifting platform for the test.
The steps of the load test of the lifting platform comprise:
carrying out a load test on the lifting platform, wherein the load test is carried out by 3 steps, and the method specifically comprises the following steps:
s151, loading 4.5 tons of materials on the lifting platform 3, and standing for 30 minutes at a position 50 cm away from the ground;
s152, loading 4.95 tons of materials on the lifting platform 3, and standing for 30 minutes at a position 50 cm away from the ground;
s153, loading 4.95 tons of materials on the lifting platform 3, and carrying 5 rounds up and down within a range of 3 meters from the ground; and if the lifting platform 3 has no welded junction crack and no steel wire rope clamp is loosened, judging that the load test of the lifting platform is qualified.
After the lifting platform is subjected to a load test, 2 chimney beams are uniformly distributed from the top to the bottom of the chimney
The steel wire rope passes through the lifting platform (guide rope) and is tensioned by a 5t hoist.
S2, erecting a tripod on the lifting platform, sequentially hoisting the top-layer diagonal bracing, the top-layer arc-shaped channel steel truss, the top-layer grid plate and the top-layer railing by using a chain block, and sequentially welding the top-layer diagonal bracing, the top-layer arc-shaped channel steel truss, the top-layer grid plate and the top-layer railing to complete the installation of the top-layer platform.
In a specific embodiment, in step S2, after the top platform is installed, the vertical ladder at the lower part of the top platform is hoisted by using a chain block; the vertical ladder is vertically vertical by using a hanging wire taper method, and the vertical ladder support is welded with the prefabricated part of the corresponding chimney cylinder wall.
Wherein, the straight ladder is prefabricated, 1-2 moulds are needed to be made when the step plate of the straight ladder is manufactured, so as to facilitate batch manufacturing; wherein, the distance between the step boards is +/-2 mm, the diagonal deviation is +/-2 mm, and the straightness of the step boards is less than or equal to 2 mm. The installation of the steel platform and the steel ladder is mainly a construction method for integrally hoisting the processed and manufactured components by a lifting platform system.
Specifically, the vertical ladder should be inserted and installed in the installation and construction process of each layer of platform, and the steel beam hanging hoist on the upper layer of platform is used for hoisting the vertical ladder on the lower part of the layer of platform. The installation adopts the installation sequence from top to bottom, and the method of the wire hanging awl is used for making the vertical ladder vertical and firmly welding the vertical ladder support with the embedded part on the cylinder wall when the vertical ladder is installed. And simultaneously carrying out rust removal and corrosion prevention on the welding position.
S3, lifting the prefabricated middle layer platform component to the mounting position of the middle layer platform by using the lifting platform, and welding the middle layer platform component to complete the middle layer platform mounting;
and S4, lifting the prefabricated bottom platform component to the mounting position of the bottom platform by using the lifting platform, and welding the bottom platform component to complete the mounting of the bottom platform.
In short, taking the installation of 5-layer steel platforms as an example, the specific construction method of each level of steel platform comprises the following steps:
1. firstly, conveying a 5 th layer of platform component into a chimney and hoisting the chimney to a lifting platform; starting a 5t winch to lift the steel beam of the 5 th-layer platform (namely the top-layer platform) to a 206m installation position; it should be noted that, the constructor should ascend with the lifting platform and the steel beam synchronously, monitor closely during the lifting process, and adjust the level of the lifting platform (the winch operation controller must be guided to the lifting platform) according to the instructions of the monitoring personnel if the steel beam inclines. In addition, all articles placed on the lifting platform are firmly bound with the lifting platform by ropes, so that the platform is prevented from inclining during lifting, the articles on the lifting platform are prevented from scattering, personnel are injured, and equipment is prevented from being damaged.
2. When the lifting platform rises to 206m, the winch is instructed to stop, the lifting platform is temporarily locked by a 5T chain block, and a constructor positions steel beams at all positions in place by using the chain block and a tripod;
3. and measuring the elevation of the horizontal beam of the 5 th-layer platform (according to the size of the outer cylinder construction indicator) by using a rope, then chiseling all embedded parts of the platform at the layer by using a hammer, and calculating the perimeter of the platform at the position by measuring the actual diameter of the embedded parts at the elevation. Further, evenly dividing the beam into 8 parts according to the circumference, namely determining the positions of 8 beams; then, the cross beam is leveled in the radial direction and the circumferential direction by using a level ruler and a water pipe for measurement, the cross beam is centered in the radial direction, and finally the cross beam is welded firmly (the cross beam is hoisted by using a tripod temporarily erected on a platform).
4. After 8 crossbeams on the 5 th layer are welded firmly, a chain block of 2t is hung on the crossbeams in a bolt mode, and the inclined supports below the crossbeams are lifted, aligned and welded. After the cross beam and the diagonal braces are welded firmly, the arc-shaped channel steel truss for supporting the steel grating plate is hoisted, the welding is firm, the grating plate and the railing are installed at last, and the platform steel structure is installed at the moment.
5. And after the steel structures of the top platform are completely installed in place, checking and accepting, welding and recording according to the drawing size.
6. And so on, the installation of the following platforms is completed step by step. When the temporary lifting platform is installed on a 2-layer platform or a 1-layer platform, the outer diameter of the temporary lifting platform needs to be correspondingly expanded. And (4) immediately checking and accepting each layer of steel beam after being installed, and laying the steel grating plate walkways and the railings in time.
In summary, the present invention relates to a chimney platform upside-down mounting construction method, which is suitable for mounting internal platforms such as high-rise buildings and structures, for example, chimneys, high towers, etc. The chimney platform is constructed from top to bottom through the self-built lifting platform, the process flow is simple, and the operation is easy; in addition, the lifting platform and the lifting equipment are light and practical, the lifting speed is high, and the construction period is effectively shortened. Platform and steel ladder steel component are according to engineering entity laying-out, processing, preparation, installation, and the deviation probability is less, and component quality is easily controlled to reach safe construction, swift construction, can reach the technological effect that effectively improves economic benefits.
However, it should be understood by those skilled in the art that various modifications can be made to the above-described method for upside-down mounting a chimney platform according to the present invention without departing from the scope of the present invention. Therefore, the scope of the present invention should be determined by the contents of the appended claims.
Claims (9)
1. A chimney platform inversion construction method is characterized by comprising the following steps:
s1, a lifting platform is set up in advance, the prefabricated top platform component is lifted to the mounting position of the top platform by the lifting platform, and the lifting platform and the concrete cylinder wall are temporarily locked by a chain block; chiseling out the embedded part of the top platform on the outer cylinder wall of the concrete according to the elevation of the horizontal beam of the top platform, and welding the cross beam corresponding to the top platform at a set position;
s2, erecting a tripod on the lifting platform, sequentially hoisting a top layer inclined support, a top layer arc-shaped channel steel truss, a top layer grid plate and a top layer railing by using a chain block, and sequentially welding the top layer platform member, the top layer inclined support, the top layer arc-shaped channel steel truss, the top layer grid plate and the top layer railing to complete the installation of the top layer platform;
s3, lifting the prefabricated middle layer platform component to the mounting position of the middle layer platform by using the lifting platform, and welding the middle layer platform component to complete the middle layer platform mounting;
and S4, lifting the prefabricated bottom platform component to the mounting position of the bottom platform by using the lifting platform, and welding the bottom platform component to complete the mounting of the bottom platform.
2. The inverted chimney platform construction method according to claim 1,
in step S2, after the top platform is mounted, the vertical ladder at the lower part of the top platform is hoisted by using the chain block;
and (3) utilizing a hanging wire taper method to enable the vertical ladder to be vertical, and welding the vertical ladder support with the prefabricated part of the corresponding chimney cylinder wall.
3. The chimney platform inverted construction method according to claim 1, wherein the building method of the lifting platform comprises the following steps:
s11, after the reinforced concrete outer cylinder of the chimney is capped, lifting the support top beam by using the scaffold lifting device;
s12, lifting the support top beam to the scaffold lifting platform by sections by using a small lifting lever, assembling and welding to complete the installation of the support top beam; the supporting top beams are installed along the direction of the flue;
s13, sequentially mounting a pulley block and a winch on the support top beam;
and S14, installing a lifting platform on the supporting sky beam.
4. The inverted construction method for the chimney platform according to claim 3, characterized in that the supporting sky beam is provided with an anti-falling rope.
5. The chimney platform upside-down construction method according to claim 3,
the supporting top beam is welded with the embedded part of the outer cylinder wall of the chimney; the supporting roof beam comprises two steel beams and a cross beam arranged between the two steel beams.
6. The inverted chimney platform construction method according to claim 3, wherein in step S14, the method for installing the lifting platform on the supporting sky beam includes:
lifting the prefabricated single-piece truss and the central cylinder to a position to be installed from the chimney through the lifting device;
assembling the single-piece truss and the central cylinder to form a lifting platform;
taking the center of the lifting platform as the center of a circle and the area with the radius of the central cylinder as the radius as the central body of the lifting platform; taking the area outside the central body of the lifting platform as a lifting platform radiator; laying a steel plate in the radiation body;
and connecting the lifting lug of the lifting platform with the lifting hook through a steel pin shaft.
7. The chimney platform upside-down construction method according to claim 6, further comprising a step of performing a load test on the lifting platform before the lifting platform is used, comprising:
loading 4.5 tons of materials on the lifting platform, and standing for 30 minutes at a height of 50 cm from the ground;
loading 4.95 tons of materials on the lifting platform, and standing for 30 minutes at a height of 50 cm from the ground;
loading 4.95 tons of materials on the lifting platform, and carrying out 5 rounds up and down within a range of 3 meters from the ground;
and if the lifting platform has no welded junction cracks and the steel wire rope clamp is not loosened, judging that the load test of the lifting platform is qualified.
8. The chimney platform upside-down construction method according to claim 6,
the single truss is formed by welding double-spliced angle steel with angle of 63; the diameter of the steel plate rolled with the central cylinder of 〥 -14 mm is
The steel cylinder of (1).
9. The inverted chimney platform construction method according to claim 6, wherein after the steel plate is laid in the radiation body, the inverted chimney platform construction method further comprises the following steps:
and a movable railing is arranged on the lifting platform.
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Application publication date: 20210622 |