1. Basis for compilation.
Urumqi Wanda Plaza Hotel and A basement construction drawings;
Code for Acceptance of Construction Quality of Concrete Structure Engineering" GB50204-2011;
Safety Technical Code for Fastener Steel Pipe Scaffolding for Building Construction JGJ130-2011;
Concrete Quality Control Standard GB50164-2011;
Engineering Practice" 05J909;
Concrete Structure Reinforcement Structure》13G311-1;
Code for Reinforcement Design of Concrete Structures GB 50367-2006;
Technical Code for Safety of Building Demolition Engineering JGJ147-2004;
Current national and local norms, standards and procedures;
Urumqi Wanda project construction organization design.
IIProject Overview
Urumqi Wanda Plaza Shopping Center - Mandarin Hotel 2-6 axis design change, between the main building and the podium seam, from the raft to add a row of frame columns. According to the on-site construction situation, the construction of the second floor roof of the basement north of the post-pouring belt on the south side of the 2-6 axis has been completed, and the second-floor wall columns, beams and slabs of the basement south of the post-pouring belt have been completed and the formwork has been erected. The construction joint is added to the basement floor due to the change, and the construction joint is left at the 2-5 axis to the south 1 3 spans, and the 2-6 axis to the north 1 3 spans, of which the 2-6 axis to the north 1 3 span wall columns, beam plate reinforcement binding and formwork support are completed, and the concrete is not poured.
According to the design change drawings of Urumqi Wanda Plaza Shopping Center - Mandarin Hotel, it is necessary to cut off the roof beam plate of the second basement floor south of the 2-6 axis of the second basement, remove the 2-D 2-F axis DKL48 of the 2-6 axis, and chisel the outer wall of the frame column at the 2-6 axis of the 2-6 axis and the 2-m axis.
In this project, rhinestones are selected for non-vibration static demolition. The demolition part is a cantilever structure, and the transfer and transportation of the excision block should be done to avoid injury to the substructure or personnel caused by the fall of the excision block. The construction process should be carried out in strict accordance with the plan, and the selection of personnel and machinery should be considered.
The demolition and reconstruction of this project is large, and the construction period is tight, cross construction, the construction site is complex, and the safety work on the site should be reasonably organized, and attention should be paid to the safety of personnel and machinery and equipment.
IIIEngineering preparation
3.1. Technical preparation.
3.1.1. Ensure that the construction drawings and design changes are complete and study carefully, organize the drawings to be reviewed, and report the drawings to the owner and the design, and communicate and solve them immediately.
3.1.2. Conscientiously study the specifications and key points of drawing operation, be familiar with the construction characteristics and requirements of the project, and make a detailed construction technical disclosure to the operation team.
3.2. Preparation of personnel and equipment.
3.2.1. Personnel preparation.
The project needs to be equipped with 6 management personnel, including 1 technician, 1 quality inspector, 1 safety officer and 3 foremen.
Participating construction personnel should include rebar workers, carpenters, concrete workers, scaffolding workers, pay-off workers, water drillers, electricians, mechanics and other construction personnel, complete types of work, and through safety education and training, special types of workers should hold valid certificates to work. The staffing is shown in the table below:
Table 1: Construction Staffing Table.
3.2.2. Preparation of the machine.
Table 2: Construction Machinery and Tools Configuration Table.
In addition, prepare a number of tape measures, wooden scrapers, iron trowels, plastic sheets, sacks, etc.
3.3 Material preparation.
1) Concrete: The concrete strength of the outer wall of the basement is C35, and the micro-expansion concrete is usedThe concrete strength of beams and slabs is C35;The concrete strength of the frame column is C60. The impermeability of waterproof concrete is designed with P6 grade.
2) Reinforcing bar: The rebar used is HPB300 hot-rolled round rebar and HRB400 hot-rolled ribbed rebar.
3) Other materials: 15mm thick wood formwork, steel pipes, fasteners, springboards, wooden squares, dense safety nets, safety nets, iron wires, wire drawing rods, butterfly cards, expansion water stops, etc.
FourthThe main construction process
Positioning and pay-off, inspecting the bottom support frame of the slab, dismantling the upper load-bearing frame of the floor slab, installing and debugging the rhinestone equipment, cutting the roof of the second underground floor, cutting the secondary beam, cutting the main beam, demolishing the exterior wall, removing the muck, binding the reinforcement of the frame column, supporting the beam and plate formwork, planting reinforcement and binding of the reinforcement of the beam and plate, and pouring concrete.
FiveConstruction methods of the main sub-projects
5.1. Measurement, positioning, and pay-off.
According to the plane coordinate control points and construction drawings provided by the owner, the total station is used to locate the position of the new frame column and the beams, slabs and wall edges to be removed. After the completion of the pay-off work, the follow-up construction work can only be carried out after the retest by the owner's supervision.
5.2. Install and debug water drilling tools.
Construction by professional rhinestone rig operators, according to the needs of the project to determine the size of the hole to choose the appropriate bit, the project is suitable for the use of a diameter of 100 bits, rhinestone rigs can only be constructed after normal installation and commissioning.
5.3. Demolition and renovation construction measures and methods.
The second floor of the basement is 54m, the concrete slab bottom beam plate formwork that needs to be cut off supports the full hall frame and can be used as the support frame for the demolition operation. The edge of the rhinestone opening should overlap with 15mm 20 to ensure that all the concrete and steel bars are cut off, the project opening is about 5070, and the concrete beam slab is cut into 15m 2m concrete block, the concrete block is completely cut off and then hoisted out and transferred by tower crane. After all the concrete is removed, the curved teeth cut by rhinestones around are chiseled off, and the cutting surface is polished and smooth, and the original structure must not be damaged when manually chiseled.
During the demolition operation, 1 safety officer and 2 foremen will be arranged to stand next to the operation.
5.3.1 Demolition and alteration of the exterior wall:
The wall that needs to be demolished is the outer wall of the second underground layer, because the construction of the demolition and reconstruction project is slow, in order not to affect the on-site backfill construction, two retaining walls are arranged on both sides of the demolition and reconstruction wall with a height of 8m, equipped with two-way c14@200, and C35 concrete is poured, as shown in Figure 1.
The 2-6 axis intersection 2-m axis is added to the frame column, and the outer wall is chiseled along the side of the 2-6 axis intersection 2-l axis column7m wide wall, the wall is 400mm thick, reinforced OS: hc14@150, vc22@200;is：hc14@150，vc20@200；tba6@300@400 plum in both directions. The 2-6 axis intersects the 2-l axis column side to the south 1The 2m range is chiseled with a drill, and the wall is 5 meters high4m, it is divided into three sections, pay attention to the hole should be drilled on both sides of the wall first, and then open a hole in the wall, used to fix the tower crane rope, when the tower crane rope hangs the wall board and the rope is in a straightened state, start the wall transverse drilling, until it is separated from the substructure and the tower crane will be transported out. There are about 220 openings, as shown in Figure 1.
After the exterior wall is removed, the curved teeth cut by rhinestones on the side of the 2-6 axis and 2-l axis frame column are chiseled off, polished and smoothed, and a groove 15mm deep and 20mm wide is chiseled along the middle of the wall to bury the expansion waterstop. Chisel the south of the wall and manually break the 500mm wall with a pickaxe, so that the original wall reinforcement is exposed.
The wall reinforcement at the frame column should be implanted into the frame column in the form of reinforcement planting, and the depth of reinforcement planting is 20d. The steel bar on the other side is welded on both sides with the steel bar chiseled out of the wall, and the welding length is 5d. The exterior wall and the new frame columns at the location of the exterior wall should be poured with slightly expanded concrete of a higher strength grade.
5.3.2 Demolition and alteration of beams and slabs:
Check whether the scaffolding that needs to be removed from the bottom of the beam and slab is fully supported and erected firmly in accordance with the construction plan of the hotel and the basement beam and plate formwork. After passing the inspection, the load-bearing scaffold on the upper part of the beam plate (that is, the roof beam plate formwork support scaffold of the basement layer has been erected) will be removed.
2-e 2-l axial intersection 2-6 to its south side post-pouring zone underground two-layer roof (i.e. -58m beam plate) Qi 2-6 axis column, beam edge overall excision, of which 2-6 axis intersection 2-D 2-F axis DKL48 along the inner edge of the beam excision. Because the dismantled beam plate is a cantilever structure, it should be gradually removed from the edge of the cantilever structure to the fixed end when dismantling, the plate should be removed first, then the secondary beam should be removed, and finally the main beam should be removed. The thickness of the plate to be cut is 300mm, as shown in Figure 3, the reinforcement of the plate surface and the bottom of the plate is c14@200, and the structural plan is shown in Figure 4, and the concrete slab is cut into 15m 2m or so concrete blocks, concrete beams cut into 15m 1m or so concrete blocks. After the concrete block is removed on three sides, it is tied and fixed with the tower crane rope, and the tower crane rope is in a straightened state and then begins to cut off the last side. When the concrete block is removed, it is lifted out with a tower crane. There are about 5,180 openings in the plate demolition project and about 2,100 holes in the beam demolition project. When excising, the bottom template of the slab, the wooden square and part of the steel pipe are excised together. The structural plan after the change is shown in Figure 5.
All the concrete is dismantled, the curved teeth cut by rhinestones around are chiseled off, the cutting surface is polished and smoothed, and the 2-5 axis to the south 1 3 spans to, 2-6 axis plate bottom support frame are all removed, and the beam plate template support frame is erected according to the change of the beam and plate position of the new frame column according to the change of the position of the beam and plate in the basement of the hotel and A.
After the beam and plate formwork is erected, the 2500mm wide plate surface north of the 2-6 axis is chiseled 40mm deep with an air pick to bury the new plate surface through reinforcement. The rest of the beam and plate reinforcement need to be planted, and the depth of reinforcement is 20d. According to the changed drawings, the beam and slab reinforcement were re-tied and the concrete was poured.
5.3.3 Added frame column reinforcement:
According to the change drawings, the position of the new frame column is positioned and set off, and the reinforcing bar is drilled with rhinestones. 122 holes were drilled, 35mm rhinestone was selected according to the size of the steel bar, the drilling depth was 25d, and the hole wall was chiseled with a percussion drill bit to weld the steel bar head after the hole was completed.
5.4. Reinforcement planting requirements.
According to the positioning and pay-off position, the depth of the column longitudinal reinforcement is not less than 25d, the depth of the beam plate is not less than 20d, and d is the diameter of the longitudinal reinforcement. The quality of the planting reinforcement should meet the following requirements:
1) The adhesive used in the structure of this project is Class A glue, which must be inspected for safety performance.
2) When the adhesive is inspected, the standard value of the adhesive shear strength should be based on the confidence level c 090. The requirement of a guarantee rate of 95.
3) The adhesive must be specially formulated modified epoxy resin adhesive or modified vinyl ester adhesive (including modified urethane adhesive), and its safety performance index must meet Table 4 in the Code for Reinforcement Design of Concrete Structures GB 50367-20065.6. The filler of the adhesive for planting anchors must be added when the factory makes the glue, and it is strictly forbidden to mix it at the construction site.
4) The shear performance of steel bonding must be qualified by damp heat aging inspection. The damp heat aging test should be carried out under the environmental conditions of 50 C temperature and 98 humidity according to the method specified in Appendix L of the Code for Reinforcement Design of Concrete Structures GB 50367-2006Aging time: not less than 90d;After the specimen after damp heat aging, the tensile shear test of steel should be carried out at room temperature, and the percentage of its strength reduction shall not be greater than 10 for grade A glue. It is not possible to use various inspection methods such as artificial weather and ultraviolet rays.
5) For the on-site inspection of the anchorage quality of the planting bar, random sampling is carried out for on-site non-damage inspection. The design value of the tensile bearing capacity of the planting reinforcement is nt=fy*as. The methods and evaluation standards of on-site inspection are shown in Appendix N of the Code for Design of Reinforcement of Concrete Structures GB 50367-2006.
OneConstruction safety assurance measures
1) In the process of operation, the safety supervision of the safety officer must be obeyed, illegal operations are prohibited, and the horizontal protection of the working surface must be done on the working surface.
2) Three-dimensional cross operation is strictly prohibited for demolition construction.
3) When the operator uses the hand-held machine, it is strictly forbidden to overload or operate with faults.
4) During the demolition operation, it is strictly forbidden for personnel to gather or stack materials on the floor slab, and the operators should stand on a stable structure or scaffolding to operate, and the dismantled components should have a safe place to be placed.
5) The demolition construction should be carried out from top to bottom, layer by layer;Non-load-bearing structures should be dismantled first, and then load-bearing structures. To dismantle the frame structure building, the construction must be carried out in the order of floor slabs, secondary beams, main beams, and columns. For buildings that are only partially demolished, the remaining parts must be reinforced before being separated.
6) When manually demolishing the building wall, it is strictly forbidden to use the method of excavation or tearing down.
7) The load-bearing beams and columns of the building should be dismantled after all the components they carry are dismantled.
8) When dismantling the beam or cantilever member, effective fall control measures should be taken to cut off the support at both ends.
9) During the construction, a special person must be responsible for monitoring the structural status of the demolished building and making a record. When it is found that there is a trend of unstable state, it is necessary to stop the operation and take effective measures to eliminate the hidden danger.
10) When dismantling the construction, the construction should be carried out in accordance with the mechanical equipment and hoisting plan selected by the construction organization design, and it is strictly forbidden to overload the operation or arbitrarily expand the scope of use. The site for the use of machinery and equipment must ensure sufficient bearing capacity, and the machinery shall not rotate and walk at the same time during operation.
11) When carrying out high-altitude demolition operations, lifting tools must be used to lift down larger components or heavy materials in time. The dismantled materials should be cleaned up in time, classified and stacked in the designated place, and it is strictly forbidden to throw them downward.
12) The scaffolding and safety net used in the demolition construction must be erected by professionals according to the design plan, and can only be used after the relevant personnel have passed the acceptance, and the operator should keep a safe distance when working horizontally.
13) When the safety protection facilities are accepted, they should be inspected item by category and have acceptance records.
14) Operators must be equipped with corresponding labor protection supplies and use them correctly.
15) The construction unit must delineate the dangerous area at the demolition construction site according to the safety construction organization design or safety special construction plan of the demolition project, and set up a cordon and related safety signs, and should send a special person to supervise.
16) During the construction of the demolition project, when a major danger or production safety accident occurs, the emergency plan should be launched in time to eliminate the danger, organize rescue, protect the accident site, and report to the relevant departments.
17) The vehicle for removing the muck should be closed or covered, and there should be a special person to direct when entering and leaving the site. The operation time of removing and transporting the muck shall comply with the relevant regulations of the place where the project is located.
18) When working at height, you must fasten your seat belt and wear safety non-slip shoes.
19) The power supply electrical appliances are responsible for the special person, and pay close attention to whether the electrical box machinery leaks
20) During the construction process, the drilling workers must strictly separate water and electricity during the construction operation, and should be equipped with insulating protective equipment, such as rubber shoes, insulating gloves and other protective equipment.
21) When prying, pulling, pushing, pulling and other operations on the working surface, you must pay attention to avoid losing your balance or throwing things out when you exert too much force.
22) When manually transferring the concrete blocks that have been cut, it is necessary to unify the command and coordinate the actions to avoid the concrete blocks from toppling and causing smashing injuries.
23) It is strictly forbidden to do other operations under and around the chiseling area, and a safety warning area is set up.