Design and construction method for installing a construction hoist on a cantilever structure

Abstract

The present invention belongs to the field of construction technology, and specifically relates to a design and construction method for installing a construction elevator on a cantilever structure. The present invention includes: the design of the elevator foundation, the recheck calculation of the bearing capacity of the cantilever structure, the construction of the elevator foundation, and the installation of the elevator. By checking the bearing capacity of the frame beam of the cantilever structure under the action of the elevator load, the construction of the elevator and the structural safety are ensured. By constructing the reinforcement according to the calculated reinforcement area of the frame beam before the construction of the cantilever structure, the technical problem that the construction of the next process is affected by the unloading support set at the bottom of the frame beam of the cantilever structure is solved. By installing a construction elevator on the cantilever structure, the problem that the construction site does not meet the installation space and position requirements of the elevator is solved, which is safe and reliable, greatly saves labor costs and construction period, and has significant economic and social benefits.

Description

Technical Field

[0001] The present invention relates to a design and construction method for installing a construction elevator on a cantilever structure, which is mainly applied to the technical field of cantilever structures. Background Art

[0002] At the design boundary between the main building and the surrounding podium buildings in construction projects, a cantilevered deformation joint is often set, or in order to enhance the front elevation effect of the main building, the conventional design spacing of decorative columns is generally less than or equal to 1.0 m, resulting in the inability to install a construction elevator at the construction site. Only manual carrying can be used to transport construction materials to the construction floors of the main building, which greatly increases a series of problems such as the secondary handling cost of materials and the construction period, and does not meet the requirements of environmental protection, energy conservation and green construction.

[0003] Chinese Patent CN105672471A discloses a construction elevator foundation and its construction method, in which one end of two box-shaped steel pipe beams is rigidly connected to a shear wall and the other end is simply supported on a frame beam, which does not meet the basic requirements of the structural balance system that the fixed support of the construction elevator foundation and the foundation weight are greater than the elevator load. Under the action of strong wind loads, the elevator lattice frame will twist and deform, and even collapse accidents may occur, which is common knowledge among professional technical personnel in the industry. This invention patent is just an idea and does not have feasibility.

[0004] In summary, the design and construction of installing a construction elevator on a cantilever structure have become a national key technical problem to be solved urgently. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a design and construction method for installing a construction elevator on a cantilever structure that is safe, reliable, economical, energy-saving, environment-friendly and easy to operate.

[0006] The design and construction method for installing a construction elevator on a cantilever structure according to the present invention is characterized by including the following steps:

[0007] I. Design of the elevator foundation

[0008] 1. Determine the geometric dimensions of the elevator foundation

[0009] The width of the elevator foundation is 50 mm to 100 mm beyond the extension of the frame beam of the cantilever structure on both sides of the deformation joint, and its length and thickness are determined according to the elevator instruction manual;

[0010] 2. Calculate the elevator load

[0011] 2.1. Calculate the elevator height according to the following formula: H = h1 - h2 + h3

[0012] In the formula: H - elevator height, unit: m;

[0013] h1 — Top elevation of building structure, unit: m;

[0014] h2 — Bottom elevation of lift foundation, unit: m;

[0015] h3 — Free end height at the top of the lift, unit: m;

[0016] 2.2. The number of standard sections is calculated by the following formula: n = H ÷ l

[0017] Where: n — Number of standard sections;

[0018] H — Lift height, unit: m;

[0019] l — Height of each standard section, unit: m;

[0020] 2.3. The design value of the self-weight of the lift is calculated by the following formula: F1 = k1(P1 + P2) + k2(P3 + P4 + P5)

[0021] Where: F1 — Design value of the self-weight of the lift, unit: kN;

[0022] k1, k2 — Dynamic coefficients of the operating load of the lift are taken as 2 and 1.4 respectively;

[0023] P1 — Self-weight of the lift cage, unit: kN;

[0024] P2 — Rated load of the lift, unit: kN;

[0025] P3 — Self-weight of the lift attachment, unit: kN;

[0026] P4 — Self-weight of the lift standard section (n × weight of a single standard section), unit: kN;

[0027] P5 — Self-weight of other accessories of the lift, unit: kN;

[0028] Among them, the self-weight of the lift includes the self-weight of the lift cage, the rated load of the lift, the self-weight of the lift attachment, the self-weight of the lift standard section, and the self-weight of other accessories of the lift.

[0029] 2.4. The design value of the uniform load on the lift foundation is calculated by the following formula:

[0030] Where: Q — Design value of the uniform load on the lift foundation, unit: KN / ㎡;

[0031] F1 — Design value of the self-weight of the lift, unit: kN;

[0032] A — Bottom area of the lift lattice frame, unit: ㎡;

[0033] 2.5. The design value of the self-weight of the lift foundation is calculated by the following formula: F2 = k3γabh

[0034] In the formula: F2—the design value of the self-weight of the lift foundation, unit: kN;

[0035] k3—the dynamic coefficient of the running load of the lift is taken as 1.2;

[0036] γ—the unit weight of reinforced concrete, unit: KN / m 3 ;

[0037] a—the length of the lift foundation, unit: m;

[0038] b—the width of the lift foundation, unit: m;

[0039] h—the thickness of the lift foundation, unit: m;

[0040] 3. Calculation of the bearing capacity of the lift foundation

[0041] 4. Setting of the edge-sealing beam of the lift foundation

[0042] The edge-sealing beams are set on both sides in the direction parallel to the width of the lift foundation;

[0043] II. Recheck calculation of the bearing capacity of the cantilever structure

[0044] 1. Calculation of the linear load of the frame beam of the cantilever structure

[0045] 1.1. The linear load of the lift self-weight acting on the frame beam of the cantilever structure is calculated according to the following formula:

[0046] In the formula: q1—the linear load of the lift self-weight acting on the frame beam, unit: KN / m;

[0047] F1—the design value of the lift self-weight, unit: kN;

[0048] a1—the effective length of the design value of the lift self-weight acting on the frame beam, taken as 1 m;

[0049] b—the width of the lift foundation, unit: m;

[0050] 1.2. The linear load of the lift foundation acting on the frame beam of the cantilever structure is calculated according to the following formula:

[0051] In the formula: q2—the linear load of the lift foundation acting on the frame beam, unit: KN / m;

[0052] F2—the design value of the self-weight of the lift foundation, unit: kN;

[0053] a—the length of the lift foundation, unit: m;

[0054] b—the width of the lift foundation, unit: m;

[0055] 2. Calculation of the bearing capacity of the cantilever structure

[0056] 3. Comparison of the design and reinforcement checking of the frame beam of the cantilever structure;

[0057] III. Construction of the lift foundation

[0058] 1. Locate the center line and side line according to the construction lift foundation design plan;

[0059] 2. Setting of the formwork support at the bottom of the lift foundation

[0060] 2.1 When there is a height difference between the cantilever structures on both sides of the deformation joint

[0061] 1) Set a support belt on the upper level of the frame beam on the higher side of the lift foundation, and set a support beam on the upper level of the frame beam on the lower side of the lift foundation, and make the top of the support belt and the support beam flush;

[0062] 2) Before installing the bottom formwork of the lift foundation on the higher side, fully lay extruded polystyrene boards, and then install the bottom formwork of the lift foundation. The construction methods of the formwork of the support beam and the bottom formwork of the lift foundation on the lower side are the same as those of the traditional technology;

[0063] 2.2 When the elevations of the cantilever structures on both sides of the deformation joint are the same

[0064] 1) Set support belts of the same height on the upper levels of the frame beams on both sides of the lift foundation;

[0065] 2) Before installing the bottom formwork of the lift foundation, fully lay extruded polystyrene boards, and then install the bottom formwork of the lift foundation;

[0066] 3. When the lift foundation is installed on the roof where the thermal insulation and waterproofing works have been completed, set wooden cushion boards at the bottom of the support belt or support beam;

[0067] 4. The construction of the side formwork, steel bar binding, and concrete pouring of the lift foundation are the same as those of the traditional construction method;

[0068] IV. Installation of the lift

[0069] 1) The concrete of the lift foundation reaches the design strength and the bottom formwork is removed;

[0070] 2) Install the construction lift by professional personnel according to the construction lift installation instructions.

[0071] The length and thickness of the lift foundation described in item 1 of step 1 are determined according to the lift instruction manual, which means determined according to the foundation design drawing in the instruction manual of the selected lift.

[0072] For the calculation of the bearing capacity of the lift foundation in Step 1, Item 3, the special-shaped plate module in the Lizheng Structural Toolbox software is used to check whether the bearing capacity, deflection, and cracks meet the requirements under the design value of the uniformly distributed local load of the orthographic projection of the lift lattice frame.

[0073] For the edge beam in Step 1, Item 4, the height of the edge beam is the same as the thickness of the lift foundation, the width meets the requirement of the height-width ratio of 2 to 3.5, and the reinforcement meets the requirement of the basic structural reinforcement ratio ≥ 0.2%.

[0074] For the calculation of the bearing capacity of the cantilever structure in Step 2, Item 2, the PKPM structural design module is used to establish models of vertical and horizontal components of three consecutive axial grids longitudinally and transversely within the range of the cantilever structures on both sides, and check whether the bearing capacity, deflection, and cracks of the frame beams of the cantilever structures on both sides meet the requirements under the action of all loads of the cantilever structure.

[0075] For the comparison between the design and verification of the reinforcement of the frame beam of the cantilever structure in Step 2, Item 3:

[0076] 1) When the structural design reinforcement of the frame beam of the cantilever structure is greater than or equal to the area of the reinforcement verified by the structure, and the deflection and cracks meet the requirements, it is determined that the frame beam of the cantilever structure meets the bearing capacity requirements;

[0077] 2) When the frame beam of the cantilever structure does not meet the bearing capacity requirements, the frame beam of the cantilever structure is constructed according to the area of the reinforcement verified, to ensure that the frame beam of the cantilever structure meets the bearing capacity requirements under the action of the lift load.

[0078] For the support belt in Step 3, Item 2, it is formed by pouring plain concrete with a thickness of 60 mm to 100 mm and a strength grade of C25 to C30.

[0079] For the support beam in Step 3, Item 2, it is a reinforced concrete beam with a reinforcement ratio ≥ 0.2% and a concrete strength grade of C25 to C30.

[0080] For the extruded polystyrene board in Step 3, Item 2, an extruded polystyrene board with a thickness of 60 mm to 100 mm is used to block the transfer of the lift foundation load to the cantilever slab and prevent the failure of the cantilever slab.

[0081] For the wooden cushion plate in Step 3, Item 3, it is to expand the contact area between the support belt or support beam and the roof insulation and waterproof layer, so that the bearing capacity of the roof insulation board meets the lift load requirements. The thickness of the wooden cushion plate is taken as 100 mm to 150 mm, and the length is calculated according to the following formula:

[0082]

[0083] In the formula: L—the length of the wooden cushion plate, unit: m;

[0084] F1—the design value of the self-weight of the lift, unit: kN;

[0085] F2—the design value of the self-weight of the lift foundation, unit: kN;

[0086] a1—the effective length of the action of the design value of the self-weight of the lift on the frame beam, taken as 1 m;

[0087] a—the length of the lift foundation, unit: m;

[0088] σ—the design value of the compressive strength of the extruded polystyrene board, unit: kN / ㎡.

[0089] The beneficial effects of the present invention are as follows:

[0090] 1) Through the design of the lift's overhanging foundation, the load of the lift is directly transmitted to the frame beam of the overhanging structure with higher bearing capacity, solving the major technical problem that it is impossible to install a construction lift on the overhanging structure.

[0091] 2) Through the bearing capacity check of the frame beam of the overhanging structure under the action of the lift load, the construction of the lift and the structural safety are guaranteed.

[0092] 3) By constructing the reinforcement according to the reinforcement area checked by the frame beam before the construction of the overhanging structure, the technical problem that the construction of the next process is affected by the unloading support set at the bottom of the frame beam of the overhanging structure is solved.

[0093] 4) By fully covering the bottom of the lift foundation with extruded polystyrene boards, the technical problem that the lift foundation load is transmitted to the overhanging slab and causes the overhanging slab to be damaged is solved.

[0094] 5) By setting wooden cushion boards at the bottom of the support belt or support beam, the contact area between the support belt or support beam and the roof waterproof protection layer is enlarged, solving the technical problem that the roof insulation layer does not meet the requirements of the lift construction load.

[0095] 6) The construction method is simple, the construction speed is fast, the comprehensive construction cost is greatly saved, there is no welding phosgene pollution, meeting the requirements of green construction and energy conservation and environmental protection, and the economic and social benefits are remarkable. Description of the Drawings

[0096] Figure 1 It is the plan view of the lift foundation design;

[0097] Figure 2 It is when there is a height difference on both sides of the deformation joint in the A-A section;

[0098] Figure 3 It is when the elevations on both sides of the deformation joint in the A-A section are the same;

[0099] Figure 4 It is when there is a height difference on both sides of the deformation joint in the A-A section and the waterproof project is completed.

[0100] In the figure: 1. Lift foundation; 2. Cantilever structure; 3. Frame beam; 4. Lift lattice frame; 5. Support belt; 6. Support beam; 7. Wooden cushion plate; 8. Thermal insulation and waterproof layer; 9. Deformation joint; 10. Edge sealing beam. Specific implementation method

[0101] The present invention will be further described below with reference to the accompanying drawings:

[0102] As Figures 1 to 4 shown, the specific steps of the design and construction method of the construction lift installed on the cantilever structure of the present invention are as follows:

[0103] I. Lift foundation design

[0104] 1. Determine the geometric dimensions of the lift foundation

[0105] The width of the lift foundation 1 is 50 mm to 100 mm outside the extension of the frame beam 3 of the cantilever structure 2 on both sides of the deformation joint 9, and its length and thickness are determined according to the lift instruction manual;

[0106] 2. Lift load calculation

[0107] 2.1. The height of the lift is calculated by the following formula: H = h1 - h2 + h3

[0108] Where: H - the height of the lift, unit: m;

[0109] h1 - the top elevation of the building structure, unit: m;

[0110] h2 - the bottom elevation of the lift foundation, unit: m;

[0111] h3 - the free end height at the top of the lift, unit: m;

[0112] 2.2. The number of standard sections is calculated by the following formula: n = H ÷ l

[0113] Where: n - the number of standard sections;

[0114] H - the height of the lift, unit: m;

[0115] l - the height of each standard section, unit: m;

[0116] 2.3. The design value of the self-weight of the lift is calculated by the following formula: F1 = k1(P1 + P2) + k2(P3 + P4 + P5) Where: F1 - the design value of the self-weight of the lift, unit: kN;

[0117] k1, k2 - the dynamic coefficients of the lift operating load are taken as 2 and 1.4 respectively;

[0118] P1 - the self-weight of the lift cage, unit: kN;

[0119] P2—the rated load of the lift, unit: kN;

[0120] P3—the self-weight of the lift attachment, unit: kN;

[0121] P4—the self-weight of the lift standard sections (n × weight of a single standard section), unit: kN;

[0122] P5—the self-weight of other accessories of the lift, unit: kN;

[0123] 2.4. The design value of the uniformly distributed load on the lift foundation is calculated according to the following formula:

[0124] Where: Q—the design value of the uniformly distributed load on the lift foundation, unit: KN / ㎡;

[0125] F1—the design value of the self-weight of the lift, unit: kN;

[0126] A—the bottom area of the lift lattice frame, unit: ㎡;

[0127] 2.5. The design value of the self-weight of the lift foundation is calculated according to the following formula: F2 = k3γabh

[0128] Where: F2—the design value of the self-weight of the lift foundation, unit: kN;

[0129] k3—the dynamic coefficient of the lift operating load, taking 1.2;

[0130] γ—the unit weight of reinforced concrete, unit: KN / m 3 ;

[0131] a—the length of the lift foundation, unit: m;

[0132] b—the width of the lift foundation, unit: m;

[0133] h—the thickness of the lift foundation, unit: m;

[0134] 3. Calculation of the bearing capacity of the lift foundation

[0135] 4. Setting of the edge sealing beam of the lift foundation

[0136] The edge sealing beam 10 is set on both sides along the width direction of the lift foundation 1;

[0137] II. Recheck calculation of the bearing capacity of the cantilever structure

[0138] 1. Calculation of the linear load of the frame beam 3 of the cantilever structure 2

[0139] 1.1. The linear load of the self-weight of the lift acting on the frame beam 3 of the cantilever structure 2 is calculated according to the following formula:

[0140] Where: q1 is the linear load exerted by the self-weight of the lift on the frame beam, unit: KN / m;

[0141] F1 is the design value of the self-weight of the lift, unit: kN;

[0142] a1 is the effective length of the design value of the self-weight of the lift acting on the frame beam, taking 1 m;

[0143] b is the width of the lift foundation, unit: m;

[0144] 1.2. The linear load of the lift foundation 1 acting on the frame beam 3 of the cantilever structure 2 is calculated according to the following formula:

[0145] Where: q2 is the linear load of the lift foundation acting on the frame beam 3, unit: KN / m;

[0146] F2 is the design value of the self-weight of the lift foundation, unit: kN;

[0147] a is the length of the lift foundation, unit: m;

[0148] b is the width of the lift foundation, unit: m;

[0149] 2. Calculation of the bearing capacity of the cantilever structure

[0150] 3. Comparison of the design and reinforcement checking of the frame beam 3 of the cantilever structure 2

[0151] III. Construction of the lift foundation

[0152] 1. Locate the center line and side line according to the design plan of the construction lift foundation 1;

[0153] 2. Setting of the formwork support at the bottom of the lift foundation

[0154] 2.1. When there is a height difference between the two cantilever structures 2 on both sides of the deformation joint 9

[0155] 1) Set the support belt 5 on the upper flat of the frame beam 3 on the higher side of the lift foundation 1, and set the support beam 6 on the upper flat of the frame beam 3 on the lower side of the lift foundation 1, and make the top of the support belt 5 flush with the top of the support beam 6;

[0156] 2) Before installing the bottom formwork of the lift foundation 1 on the higher side, fully lay the extruded polystyrene board, and then install the bottom formwork of the lift foundation 1. The construction methods of the formwork of the support beam 6 on the lower side and the bottom formwork of the lift foundation 1 are the same as those of the traditional technology;

[0157] 2.2. When the elevations of the two cantilever structures 2 on both sides of the deformation joint 9 are the same

[0158] 1) Set the support belts 5 with the same height on the upper flats of the frame beams 3 on both sides of the lift foundation 1;

[0159] 2) Before installing the bottom formwork of the lift foundation 1, fully lay extruded polystyrene boards, and then install the bottom formwork of the lift foundation 1.

[0160] 3. When the lift foundation 1 is installed on the roof where the thermal insulation and waterproof layer 8 project has been completed, set wooden cushion blocks 7 at the bottom of the support belt 5 or the support beam 6.

[0161] 4. The construction of the side formwork, steel bar binding, and concrete pouring of the lift foundation 1 are the same as the traditional construction methods.

[0162] IV. Lift Installation

[0163] 1) The concrete of the lift foundation 1 reaches the design strength and the bottom formwork is removed.

[0164] 2) Install the construction lift by professional personnel according to the installation instructions of the construction lift.

[0165] Among them:

[0166] The length and thickness of the lift foundation 1 described in item 1 of step 1 are determined according to the lift instruction manual, which means determined according to the foundation design drawing in the instruction manual of the selected lift.

[0167] For the bearing capacity calculation of the lift foundation 1 described in item 3 of step 1, the special-shaped plate module in the Lizheng Structural Toolbox software is used to check whether the bearing capacity, deflection, and cracks meet the requirements under the design value of the uniformly distributed local load of the orthographic projection of the lift grid frame 4.

[0168] The height of the edge-sealing beam 10 described in item 4 of step 1 is the same as the thickness of the lift foundation 1, the width meets the requirement of the height-width ratio of 2 - 3.5, and the steel bar reinforcement meets the requirement of the basic structural reinforcement ratio ≥ 0.2%.

[0169] For the bearing capacity calculation of the cantilever structure 2 described in item 2 of step 2, the PKPM structural design module is used to respectively establish the models of vertical and horizontal components of three consecutive axial grids in the longitudinal and transverse directions within the range of the two-sided cantilever structure 2, and check whether the bearing capacity, deflection, and cracks of the frame beam 3 of the two-sided cantilever structure 2 meet the requirements under the action of all loads of the cantilever structure 2.

[0170] Comparison of the design and verification of the reinforcement of the frame beam 3 of the cantilever structure 2 described in item 3 of step 2:

[0171] 1) When the structural design reinforcement of the frame beam 3 of the cantilever structure 2 is greater than or equal to the structural verification reinforcement area, and the deflection and cracks meet the requirements, it is determined that the frame beam 3 of the cantilever structure 2 meets the bearing capacity requirements.

[0172] 2) When the frame beam 3 of the cantilever structure 2 does not meet the bearing capacity requirements, construct the frame beam 3 of the cantilever structure 2 according to the calculated reinforcement area to ensure that the frame beam 3 of the cantilever structure 2 meets the bearing capacity requirements under the action of the elevator load.

[0173] The support belt 5 described in item 2 of step three is formed by pouring plain concrete with a thickness of 60 mm to 100 mm and a strength grade of C25 to C30.

[0174] The support beam 6 described in item 2 of step three is a reinforced concrete beam with a reinforcement ratio ≥ 0.2% and a concrete strength grade of C25 to C30.

[0175] The extruded polystyrene board described in item 2 of step three is an extruded polystyrene board with a thickness of 60 mm to 100 mm, which blocks the transfer of the elevator foundation 1 load to the cantilever slab and prevents the cantilever slab from being damaged.

[0176] The wooden cushion plate 7 described in item 3 of step three is to expand the contact area between the support belt 5 or the support beam 6 and the roof thermal insulation and waterproof layer 8 so that the bearing capacity of the roof insulation board meets the elevator load requirements. The thickness of the wooden cushion plate 7 is taken as 100 mm to 150 mm, and the length is calculated by the following formula:

[0177]

[0178] In the formula: L—the length of the wooden cushion plate, unit: m;

[0179] F1—the design value of the self-weight of the elevator, unit: kN;

[0180] F2—the design value of the self-weight of the elevator foundation, unit: kN;

[0181] a1—the effective length of the design value of the self-weight of the elevator acting on the frame beam, taken as 1 m;

[0182] a—the length of the elevator foundation, unit: m;

[0183] σ—the design value of the compressive strength of the extruded polystyrene board, unit: kN / ㎡.

Claims

1. A design and construction method for installing a construction elevator on a cantilever structure, characterized by including the following steps: I. Design of the elevator foundation 1. Determine the geometric dimensions of the elevator foundation The width of the elevator foundation is 50 mm to 100 mm beyond the extension of the frame beam of the cantilever structure on both sides of the deformation joint, and its length and thickness are determined according to the elevator instruction manual; 2. Calculate the load of the elevator and the elevator foundation 2.

1. Calculate the height of the elevator according to the following formula: H = h1 - h2 + h3 Where: H - the height of the elevator, unit: m; h1 - the top elevation of the building structure, unit: m; h2 - the bottom elevation of the elevator foundation, unit: m; h3 - the free end height at the top of the elevator, unit: m; 2.

2. Calculate the number of standard sections according to the following formula: n = H ÷ l Where: n - the number of standard sections; H - the height of the elevator, unit: m; l - the height of each standard section, unit: m; 2.

3. Calculate the design value of the self-weight of the elevator according to the following formula: F1 = k1(P1 + P2) + k2(P3 + P4 + P5) Where: F1 - the design value of the self-weight of the elevator, unit: kN; k1, k2 - the dynamic coefficients of the elevator operating load are taken as 2 and 1.4 respectively; P1 - the self-weight of the elevator cage, unit: kN; P2 - the rated load of the elevator, unit: kN; P3 - the self-weight of the elevator attachment, unit: kN; P4 - the self-weight of the elevator standard section, the self-weight of the elevator standard section = n × the weight of a single standard section, unit: kN; P5 - the self-weight of other accessories of the elevator, unit: kN; 2.

4. Calculate the design value of the uniform load on the elevator foundation according to the following formula: Where: Q - the design value of the uniform load on the elevator foundation, unit: KN / ㎡; F1 - the design value of the self-weight of the elevator, unit: kN; A - the bottom area of the elevator lattice frame, unit: ㎡; 2.

5. Calculate the design value of the self-weight of the elevator foundation according to the following formula: F2 = k3γabh Where: F2 - the design value of the self-weight of the elevator foundation, unit: kN; The dynamic coefficient of the operating load of the lift is taken as 1.2; γ—Unit weight of reinforced concrete, unit: KN / m 3 ; a—Length of the lift foundation, unit: m; b—Width of the lift foundation, unit: m; h - Thickness of the lift foundation, unit: m; 3. Calculation of the bearing capacity of the lift foundation 4. Setting of the edge-sealing beam of the lift foundation Edge-sealing beams are set on both sides parallel to the width direction of the lift foundation; II. Recheck calculation of the bearing capacity of the cantilever structure 1. Calculation of the linear load of the frame beam of the cantilever structure 1.

1. The linear load of the lift self-weight acting on the frame beam of the cantilever structure is calculated according to the following formula: In the formula: q1—The linear load of the lift self-weight acting on the frame beam, unit: KN / m; F1—Design value of the lift self-weight, unit: kN; a1—Effective length of the design value of the lift self-weight acting on the frame beam, taken as 1 m; b—Width of the lift foundation, unit: m; 1.

2. The linear load of the lift foundation acting on the frame beam of the cantilever structure is calculated according to the following formula: Where: q2—the linear load exerted by the lift foundation on the frame beam, unit: KN / m; F2—the design value of the self-weight of the lift foundation, unit: kN; a—the length of the lift foundation, unit: m; b—the width of the lift foundation, unit: m; 2. Calculation of the bearing capacity of the cantilever structure 3. Comparison of the design and reinforcement checking of the frame beam of the cantilever structure; III. Construction of the lift foundation 1. Locate the center line and side lines according to the construction lift foundation design plan; 2. Setting of the formwork support at the bottom of the lift foundation 2.

1. When there is a height difference between the cantilever structures on both sides of the deformation joint 1) A support belt is set on the upper level of the frame beam on the higher side of the lift foundation, and a support beam is set on the upper level of the frame beam on the lower side of the lift foundation, and the support belt and the top of the support beam are made flush; 2) Before installing the bottom formwork of the lift foundation on the higher side, extruded polystyrene boards are fully paved, and then the bottom formwork of the lift foundation is installed. The construction methods of the support beam formwork and the bottom formwork of the lift foundation on the lower side are the same as those of the traditional technology; 2.

2. When the elevations of the cantilever structures on both sides of the deformation joint are the same 1) Support belts of the same height are set on the upper levels of the frame beams on both sides of the lift foundation; 2) Before installing the bottom formwork of the lift foundation, fully lay extruded polystyrene boards, and then install the bottom formwork of the lift foundation; 3. When the lift foundation is installed on the roof where the thermal insulation and waterproofing works have been completed, set wooden cushion boards at the bottom of the support belt or support beam; 4. The construction of the side formwork of the lift foundation, steel bar binding, and concrete pouring are the same as the traditional construction methods; IV. Lift Installation 1) The concrete of the lift foundation reaches the design strength and the bottom formwork is removed; 2) Install the construction lift by professional personnel in accordance with the installation instructions of the construction lift.

2. The design and construction method for installing a construction lift on the cantilever structure according to claim 1, wherein: The length and thickness of the lift foundation described in item 1 of step 1 are determined according to the lift instruction manual, which means determined according to the foundation design drawing in the instruction manual of the selected lift.

3. The design and construction method for installing a construction lift on the cantilever structure according to claim 1, wherein: The calculation of the bearing capacity of the lift foundation described in item 3 of step 1 is to use the special-shaped plate module in the Lizheng Structural Toolbox software to check whether the bearing capacity, deflection and cracks meet the requirements under the design value of the local uniform load of the orthographic projection of the lift lattice frame.

4. The design and construction method for installing a construction lift on the cantilever structure according to claim 1, wherein: The height of the edge-sealing beam described in item 4 of step 1 is the same as the thickness of the lift foundation, the width meets the requirement of the height-width ratio of 2 - 3.5, and the reinforcement meets the requirement of the basic structural reinforcement ratio ≥ 0.2%.

5. The design and construction method for installing a construction lift on the cantilever structure according to claim 1, wherein: The calculation of the bearing capacity of the cantilever structure described in item 2 of step 2 is to use the PKPM structural design module to establish models of vertical and horizontal components of three consecutive axial grids in the longitudinal and transverse directions within the range of the cantilever structures on both sides respectively, and check whether the bearing capacity, deflection and cracks of the frame beams of the cantilever structures on both sides meet the requirements under the action of all loads of the cantilever structure.

6. The design and construction method for installing a construction lift on the cantilever structure according to claim 1, wherein: Comparison of the design and reinforcement checking of the frame beam of the cantilever structure described in item 3 of step 2: 1) When the structural design reinforcement of the frame beam of the cantilever structure is greater than or equal to the reinforcement area of the structural checking, and the deflection and cracks meet the requirements, it is determined that the frame beam of the cantilever structure meets the bearing capacity requirements; 2) When the frame beam of the cantilever structure does not meet the bearing capacity requirements, construct the frame beam of the cantilever structure according to the reinforcement area of the checking to ensure that the frame beam of the cantilever structure meets the bearing capacity requirements under the action of the lift load.

7. The design and construction method for installing a construction lift on the cantilever structure according to claim 1, wherein: The support belt described in item 2 of step 3 is formed by pouring plain concrete with a thickness of 60mm - 100mm and a strength grade of C25 - C30.

8. The design and construction method for installing a construction lift on the cantilever structure according to claim 1, wherein: The support beam described in item 2 of step 3 is a reinforced concrete beam with a reinforcement ratio ≥ 0.2% and a concrete strength grade of C25 - C30.

9. The design and construction method for installing a construction lift on the cantilever structure according to claim 1, wherein: The extruded polystyrene board described in item 2 of step 3 is an extruded polystyrene board with a thickness of 60mm - 100mm to block the transfer of the lift foundation load to the cantilever slab and prevent the failure of the cantilever slab.

10. The design and construction method for installing a construction lift on the cantilever structure according to claim 1, wherein: The wooden cushion plate described in item 3 of step 3 is to expand the contact area between the support belt or support beam and the roof thermal insulation and waterproof layer so that the bearing capacity of the roof insulation board meets the lift load requirements. The thickness of the wooden cushion plate is taken as 100mm - 150mm, and the length is calculated according to the following formula: Where: L—the length of the wooden cushion plate, unit: m; F1—the design value of the self-weight of the lift, unit: kN; F2—the design value of the self-weight of the lift foundation, unit: kN; a1—the effective length of the design value of the self-weight of the lift acting on the frame beam, taken as 1m; a—the length of the lift foundation, unit: m; σ—the design value of the compressive strength of the extruded polystyrene board, unit: kN / ㎡.

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