阅读说明：本技术 一种逆作式悬挑脚手架搭设方法 (Method for erecting reverse-construction type overhanging scaffold ) 是由 刘令良 胡小兵 孔正武 蒋涛 张磊 于 2020-05-20 设计创作，主要内容包括：一种逆作式悬挑脚手架搭设方法,包括以下步骤：1)搭设上层脚手架的首步架：在下层脚手架上预先搭设上层脚手架的首步架,使首步架中悬挑立杆的底端高出悬挑层楼面；2)在悬挑层楼面预埋锚固件：根据悬挑钢梁的安装位置预埋锚固件；3)安装悬挑钢梁：通过锚固件安装悬挑钢梁,在悬挑钢梁上安装定位支座；4)放松首步架至悬挑钢梁：悬挑钢梁安装好后,将悬挑立杆降落到悬挑钢梁上并用定位支座定位；5)上层脚手架的上层架体搭设：放松首步架后,按照常规搭设方法搭设上层脚手架的上层架体。本发明搭设方法消除了悬挑钢梁安装防护缺失的重大安全隐患,实现了悬挑层架体安全防护100%到位,有效保证了悬挑层架体的安全性能。(A method for building a reverse cantilever scaffold comprises the following steps: 1) the first step of building an upper scaffold: a first step frame of an upper scaffold is pre-erected on a lower scaffold, so that the bottom end of a cantilever vertical rod in the first step frame is higher than the floor of the cantilever floor; 2) embedding anchoring parts in the floor of the overhanging floor: embedding anchoring parts according to the installation position of the cantilever steel beam; 3) installing an overhanging steel beam: mounting an overhanging steel beam through an anchoring piece, and mounting a positioning support on the overhanging steel beam; 4) loosening the first step frame to the cantilever steel beam: after the cantilever steel beam is installed, the cantilever upright rod is descended onto the cantilever steel beam and is positioned by the positioning support; 5) the upper layer of the scaffold body of the upper layer is set up: and after the first step frame is loosened, an upper layer frame body of an upper layer scaffold is erected according to a conventional erection method. The erection method eliminates the major potential safety hazard of the mounting protection loss of the cantilever steel beam, realizes 100% in-place safety protection of the cantilever layer frame body, and effectively ensures the safety performance of the cantilever layer frame body.)

1. A method for erecting a reverse-construction type overhanging scaffold is characterized by comprising the following steps:

1) the first step of building an upper scaffold: taking a lower-layer scaffold extending out of the overhanging floor as a support, hanging a first step frame of an upper-layer scaffold in advance on the lower-layer scaffold, and enabling the bottom end of a hanging upright rod in the first step frame to be higher than the overhanging floor;

2) embedding anchoring parts in the floor of the overhanging floor: after the first step frame is erected, determining the mounting position of the cantilever steel beam and pre-burying an anchoring piece according to the mounting position of the cantilever steel beam;

3) installing an overhanging steel beam: after the concrete of the floor of the overhanging layer reaches the strength, installing an overhanging steel beam through an anchoring part, and meanwhile, installing a positioning support on the overhanging steel beam;

4) loosening the first step frame to the cantilever steel beam: after the cantilever steel beam is installed, the cantilever upright rod is descended onto the cantilever steel beam and is positioned through the positioning support;

5) the upper layer of the scaffold body of the upper layer is set up: after the first step frame is loosened to the cantilever steel beam, the upper layer frame body in the upper layer scaffold can be erected according to a conventional erection method.

2. The method for erecting a reverse-acting overhanging scaffold according to claim 1, wherein the bottom ends of the overhanging poles in the first step of step 1) are connected to the lower beams of the lower scaffold by fasteners, and diagonal braces are provided between the overhanging poles and the lower scaffold, and small beams are fixed between the overhanging poles.

3. The method for erecting a reverse-acting overhanging scaffold according to claim 2, wherein the overhanging vertical rods are dropped onto the overhanging steel beams by removing the fasteners in step 4).

4. The method for erecting a reverse-acting overhanging scaffold according to claim 3, wherein the step 5) further comprises connecting the overhanging poles and the lower layer cross bars together by fasteners.

5. The method for setting up the overhung scaffold according to claim 1, wherein the method for determining the installation position of the overhanging steel beam in the step 2) comprises the following steps: and (3) projecting laser by using a laser projector and aligning the laser with the lower end of the cantilever vertical rod, wherein the laser projection position is the central line of the mounting position of the cantilever steel beam.

6. The method for erecting a reverse cantilever scaffold according to claim 1, wherein the fixed end length of the cantilever steel beam in the step 3) is not less than 1.25 times the cantilever end length.

7. The method for erecting the reverse-acting type overhanging scaffold according to claim 1, wherein the positioning support of the step 3) comprises a base and a limiting sleeve, the base is detachably fixed on the overhanging steel beam, and the limiting sleeve is fixed on the base; and 4) positioning the cantilever vertical rod through a limiting sleeve.

8. The method for erecting a reverse-acting overhanging scaffold according to claim 7, wherein the base is made of channel steel, through holes are formed at both sides of the base, and fastening bolts are passed through the through holes to fix the base on the outer side of the overhanging steel beam.

9. The method for erecting a reverse-acting overhanging scaffold according to claim 1, wherein the step 1) further comprises erecting a lower scaffold diagonal support between the lower scaffold and the lower floor.

Technical Field

The invention belongs to the field of construction of constructional engineering, and particularly relates to a method for building a reverse cantilever scaffold.

Background

The cantilever scaffold is widely applied to a multi-layer or high-rise building main structure construction outer frame, and the conventional cantilever scaffold building method generally comprises the steps of pre-embedding an anchor ring in a cantilever layer, installing a cantilever steel beam after concrete pouring is completed and certain strength is achieved, and finally building a cantilever scaffold body. When setting up the cantilever support body, because the operation personnel do not have outer protection, the potential safety hazard is big, often need set up in addition interim protection in order to ensure constructor's safety, therefore lead to the construction process many, construction cycle is longer. In addition, the vertical rods on the cantilever frame are usually positioned by the fixed steel bar heads prewelded on the cantilever steel beams, but the vertical rods are easy to deviate relative to the fixed steel bar heads of the steel pipes, and the fixed steel bar heads cannot adjust the positions, so that the vertical rods cannot be installed quickly and accurately, and the construction period is influenced.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: the method overcomes the defects of a conventional overhanging scaffold erection method, provides a reverse-construction overhanging scaffold erection method, and aims to eliminate major potential safety hazards caused by missing protection when an overhanging steel beam is installed, reduce the processes of erecting and dismantling temporary protection and accelerate the construction progress.

The technical scheme adopted by the invention is as follows: a method for building a reverse cantilever scaffold comprises the following steps:

1) the first step of building an upper scaffold: taking a lower-layer scaffold extending out of the overhanging floor as a support, hanging a first step frame of an upper-layer scaffold in advance on the lower-layer scaffold, and enabling the bottom end of a hanging upright rod in the first step frame to be higher than the overhanging floor;

2) embedding anchoring parts in the floor of the overhanging floor: after the first step frame is erected, determining the mounting position of the cantilever steel beam and pre-burying an anchoring piece according to the mounting position of the cantilever steel beam;

3) installing an overhanging steel beam: after the concrete of the floor of the overhanging layer reaches the strength, installing an overhanging steel beam through an anchoring part, and meanwhile, installing a positioning support on the overhanging steel beam;

4) loosening the first step frame to the cantilever steel beam: after the cantilever steel beam is installed, the cantilever upright rod can be descended onto the cantilever steel beam and positioned through the positioning support;

5) the upper layer of the scaffold body of the upper layer is set up: after the first step frame is loosened to the cantilever steel beam, the upper layer frame body in the upper layer scaffold can be erected according to a conventional erection method.

Preferably, the bottom of the vertical pole of encorbelmenting in step 1) first step adopts the fastener to connect on the lower floor's horizontal pole of lower floor's scaffold to set up the diagonal brace between the vertical pole of encorbelmenting and lower floor's scaffold, fixed little horizontal pole between the vertical pole of encorbelmenting simultaneously.

Preferably, the overhanging vertical rod is dropped onto the overhanging steel beam by removing the fastener in the step 4).

Preferably, step 5) further comprises connecting the overhanging pole and the lower layer cross bar together through a fastener.

Preferably, the method for determining the installation position of the cantilever steel beam in the step 2) comprises the following steps: and (3) projecting laser by using a laser projector and aligning the laser with the lower end of the cantilever vertical rod, wherein the laser projection position is the central line of the mounting position of the cantilever steel beam.

Preferably, the fixed end length of the cantilever steel beam in the step 3) is not less than 1.25 times of the cantilever end length.

Preferably, the positioning support in the step 3) comprises a base and a limiting sleeve, the base is detachably fixed on the cantilever steel beam, and the limiting sleeve is fixed on the base; and 4) positioning the cantilever vertical rod through a limiting sleeve.

Preferably, the base is made of channel steel, through holes are formed in two sides of the base, and fastening bolts penetrate through the through holes to fix the base on the outer side of the cantilever steel beam.

Preferably, step 1) further comprises building a lower-layer scaffold inclined support between the lower-layer scaffold and the lower-layer floor.

The invention has the beneficial effects that:

1. according to the cantilever beam mounting method, the cantilever beam is mounted after the first step frame is cantilevered and pre-erected, so that the major potential safety hazard of mounting protection loss of the cantilever beam is eliminated, the safety protection of the cantilever layer frame body is 100% in place, and the safety performance of the cantilever layer frame body is effectively ensured;

2. the first step frame erected in the air is also used as a protective frame, so that the process of additionally erecting and dismantling the temporary protective handrail is reduced, compared with the conventional construction method that the temporary protection needs to be erected firstly, and the protective frame is dismantled after the cantilever beam is installed, so that the construction progress is accelerated, the labor and protective materials are saved, and the construction cost is greatly reduced;

3. the movable positioning support is adopted on the cantilever steel beam, so that the quick and accurate positioning of the vertical rod is ensured, the open flame welding operation of welding short steel bars on the steel beam is reduced, the potential safety hazard is reduced, the positioning support can be repeatedly recycled after being detached, and the cantilever steel beam is safe, economical and environment-friendly.

Drawings

FIG. 1 is a schematic flow diagram of the method for setting up the cantilever scaffold according to the present invention;

FIG. 2 is a front view of the flying preattack step of the present invention;

FIG. 3 is a side view of the overhead preattaching step of the present invention;

FIG. 4 is a sectional view of the cantilever beam and the first step of the present invention;

FIG. 5 is an installation view of the positioning pedestal and vertical rod of the present invention;

FIG. 6 is a block diagram of the alignment bracket of the present invention.

Detailed Description

The invention is further illustrated by the following figures and examples.

As shown in fig. 1 to 6, a method for erecting a reverse cantilever scaffold includes the following steps:

step 1) hanging a first scaffold 1 of an upper scaffold: when setting up the scaffold body of upper strata, utilize the lower floor scaffold 2 who stretches out overhanging floor 3 as the support, unsettled first step frame 1 of setting up upper scaffold in advance on lower floor scaffold 2 to guarantee to have certain unsettled height between the pole 11 bottom of overhanging in first step frame 1 and the floor 3 of overhanging floor, wherein unsettled height is confirmed by overhanging girder steel 4 height h1+ spacing sleeve pipe height h2+ reservation height h3 (namely unsettled height h = h1+ h2+ h 3). The setting method of the first step frame 1 comprises the following steps: adopt fastener 7 to connect the pole 11 of encorbelmenting of first step frame 1 on the lower floor horizontal pole 22 of lower floor scaffold frame 2 to set up between pole 11 of encorbelmenting and lower floor scaffold frame 2 and support with diagonal brace 12, the little horizontal pole 13 of fixed connection between pole 11 of encorbelmenting simultaneously, in order to guarantee the stability of first step frame 1 structure.

In this step, the lower scaffolding 2 to be supported must be set up strictly according to the design interval and the specification. The height of the lower-layer upright stanchion 21 extending out of the overhanging-layer floor 3 in the lower-layer scaffold 2 is preferably controlled to be 0.6m, and the requirement for fixing the upper-layer scaffold upright stanchion can be met. In order to unload the load of the pre-landing step frame 1, a lower-layer frame body inclined support 23 is arranged between the lower-layer floor 9 and the lower-layer scaffold 2.

Step 2) embedding anchoring parts 5 in the overhanging floor: and positioning and paying off by adopting a laser line projector, aligning the laser projected by the laser line projector with the lower end of the cantilever upright rod 11, and then enabling the laser projection position to be the central line of the mounting position of the cantilever steel beam 4. And embedding anchoring parts at two sides of the mounting position of the cantilever steel beam according to the mounting position of the cantilever steel beam.

In the step, an anchoring part 5 adopts a U-shaped unbonded and nondestructive easy-to-detach anchor ring, the diameter, the length and the like of the anchoring part are determined according to the construction scheme of an upper scaffold, an anchoring part processing plan is made, after a floor bottom die is erected, the anchoring position on a template is positioned and paid off according to a profile steel and anchor ring layout, the anchor ring is fixed on the template by iron nails according to the position of a plane layout after penetrating into a plastic base, then butter is smeared on screw rods on two sides of the anchor ring and a PVC protective sleeve is sleeved on the screw rods, and the upper opening and the thread teeth of the screw rods are protected by adhesive tapes.

Step 3), installing an overhanging steel beam 4: the cantilever steel beam 4 is installed when the concrete of the cantilever floor 3 can completely bear the load of the operation on the upper scaffold and the frame body. The cantilever steel beam 4 is fixed by the pre-buried anchoring piece 5, the length of the fixed end of the cantilever steel beam 4 is not less than 1.25 times of the length of the cantilever end, and the connection with a building must be reliable. The fixing method with the anchor 5 comprises the following steps: the anchoring part 5 adopts an anchor ring, firstly tears off the adhesive tape on the upper end of the screw thread, then directly arranges the cantilever steel beam 4 in the middle of the anchor ring, presses up a steel plate and a gasket, firstly simply fixes by using a single nut, after the cantilever steel beam 4 is accurately aligned and positioned with the fixed point of the cantilever vertical rod, a second nut is screwed up and fixed firmly, the lateral gap between the anchor ring and the cantilever steel beam 4 is blocked by a wedge, and the end part of each cantilever steel beam 4 is reinforced by adopting a steel wire rope 8 to be inclined.

In this step, a positioning support 6 should be installed on the cantilever steel beam 4. The positioning support 6 consists of a movable base 61 and a limiting sleeve 63, wherein the base 61 is made of No. 18 channel steel with the length of 120mm, and the limiting sleeve 63 is made of a short steel pipe with the height of 100mm and the diameter of 55 mm. The limiting sleeve 63 is welded in the middle of the web plate of the base 61, and two sides of the flange of the base 61 are drilled and symmetrically provided with a pair of fastening bolts 62.

Step 4) loosening the first step frame 1 to the cantilever steel beam 4: after the cantilever steel beam 4 is installed, the bottom end of the cantilever upright rod 11 which is erected in advance can be descended onto the cantilever steel beam 4 and the cantilever upright rod 11 is positioned by adopting the limiting sleeve 63. Specifically be, remove base 61 to the pole 11 lower extreme of encorbelmenting earlier, will encorbelment pole 11 and descend to spacing sleeve pipe 63 one by one in, reuse fastening bolt 62 is fixed base 61, and reuse fastener 7 will encorbelment pole 11 and lower floor's horizontal pole 22 and link together simultaneously to accurate control encorbelments pole 11's positional deviation, prevents that the pole 11 that encorbelments from sliding and off normal.

Step 5), setting up an upper layer frame body of an upper layer scaffold: after the first step frame 1 is loosened to the cantilever steel beam 4, the upper layer frame body of the upper layer scaffold can be erected according to a conventional erection method. According to the special construction scheme and the standard requirements, the large cross rods, the scissor supports, the scaffold boards and the like are respectively erected, and wall connecting pieces are reserved according to the requirements. After each section of the scaffold is erected, the scaffold can be accepted for use after being checked and accepted.

The invention is suitable for the erection of the cantilever external scaffold in the construction of the main structure of a multi-storey or high-rise residence. The following are two specific engineering examples applying the construction technology of the invention:

example one

A four-section project of an installation project of a certain arrangement community has the project building area of 56963.47 m2, the construction cost of 11419.33 ten thousand yuan, the underground layer and the underground 24 layer. The common landing scaffold is adopted for the 1-3 floors of the skirt building, the 16# I-steel overhanging scaffold is adopted for the 4 floors, the reverse construction type overhanging scaffold construction technology is applied to the project, the construction quality and the safety are reliably guaranteed, no safety accidents of any size occur, the construction period is shortened by about 6 days compared with the conventional construction technology, the material and labor cost is reduced by 27000 yuan, and the economic benefit is obvious.

Example two

The total building area of a project of a school in the first period of reconstruction and extension is about 100075.91m 2. The comprehensive building (15 #) and the shift building (23 #) are high-rise buildings, overhanging scaffolds are erected in three sections from above the second floor during main construction, the total height of the overhanging scaffolds is 51.3m, and 18# I-steel is adopted. The overhanging scaffold adopts a reverse construction type overhanging scaffold construction technology, avoids the loss of outer frame protection when the overhanging scaffold is erected, eliminates potential safety hazards, has no safety accidents in the construction process, and obtains the consistent and favorable comment of construction and supervision units. Compared with the conventional construction process, the construction period is shortened by about 7 days, the material and labor cost is reduced by 32000 yuan, and the economic benefit is obvious.