Steel frame construction method for old building transformation

Abstract

According to the steel frame construction method for old building transformation, the problem that it is difficult to guarantee that the original appearance of an outer wall of an original building can not be completely reserved on the basis that the commercial use structure requirement and the function requirement are met through a traditional old community transformation technology is solved. The method comprises the steps that geological investigation is conducted on the area where an old building needing to be transformed is located, structural characteristics of the old building are analyzed and calculated, a steel frame structure system and an old building reinforcing system outside the old building are designed, and the old building is reinforced according to the steel frame structure system and the old building reinforcing system outside the old building. According to the principle that an old building reinforcing system does not damage a strip-shaped foundation of an original structure of the old building, a beam plate type raft foundation is adopted, foundation reinforcing treatment is conducted on the old building, operation guarantee is provided for construction of a steel frame structure, and then after cracks of an original wall face are repaired, a roof is dismantled and repaired. And landscape building protective transformation which is ecological, suitable for swimming, suitable for industry and harmonious is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of building construction, in particular to a steel frame construction method for old building reconstruction. Background Art

[0002] With the development of social economy and the improvement of living environment, residential areas in cities that were built early, have outdated facilities and potential safety hazards can no longer meet people's related needs. These areas not only affect the quality of life of residents, but also restrict the sustainable development of cities. Therefore, the renovation of old residential areas has important practical significance. In the process of renovation, the historical and cultural value and modern needs of the community should be fully considered, with the goal of achieving a perfect integration of history and modernity, and improving the overall quality of the community and the quality of life of residents.

[0003] Most of the traditional methods of renovating old residential communities are to directly demolish and rebuild, which generates a large amount of solid waste. With the reconstruction of underground pipe networks and community roads, the original appearance and memory of the community will be gone. The cleaning and treatment of solid waste such as demolished wall bricks also requires a certain amount of cost. In addition, the traditional renovation of old residential communities focuses on residential functions and pays less attention to rejuvenation. It is difficult to ensure that the original appearance of the original building's exterior wall can be relatively intact while meeting the structural requirements and functional needs of commercial use. Summary of the invention

[0004] In order to solve the problem that traditional old residential area renovation technology in the background technology is difficult to ensure that the original appearance of the exterior wall of the original building can be relatively completely preserved on the basis of meeting the structural requirements and functional needs of commercial use, the present invention proposes a steel frame construction method for old building renovation.

[0005] The technical solution of the present invention is: a steel frame construction method for old building reconstruction, comprising the following steps: step 1, conducting geological survey on the area where the old building to be reconstructed is located, forming a geological survey report, and obtaining the maximum geological foundation load; Step 2: Analyze and calculate the structural characteristics of the old building, and design the steel frame structure system and the reinforcement system of the old building based on the maximum geological foundation load. Use the three-dimensional model technology to calculate and verify the construction sequence and structural load of the steel frame structure system and the reinforcement system of the old building, to ensure that the total load of the steel frame structure system and the reinforcement system of the old building at each construction stage is less than the maximum geological foundation load. Step 3: Based on the design of the old building reinforcement system, the original strip foundation of the old building is used, and the beam-slab raft foundation is used to reinforce the foundation of the old building without any damage to the original strip foundation of the old building. Step 4: Based on the design of the steel frame structure system, a steel frame structure system is constructed on the basis of the reinforcement treatment around the old building to provide auxiliary support for the old building; Step 5: According to the design of the old building reinforcement system, the exterior walls of the old buildings are reinforced with board walls and the cracks in the walls are repaired; Step six: Based on the design of the old building reinforcement system, the roof of the old building is protectively dismantled, repaired and rebuilt.

[0006] Preferably, in step 1, when conducting geological survey, drawings of old buildings are simultaneously drawn to check the distribution and usage status of pipelines in the old buildings; In step three, before reinforcing the foundation of the old building, the pipelines of the old building are first dismantled and modified.

[0007] Preferably, before the foundation reinforcement treatment of the old building is carried out in step three, the external blockages in the old building are first removed, and then the doors and windows, ceilings and suspended ceilings are removed, and finally the non-bearing structures are removed.

[0008] Preferably, in step 4, when a steel frame structure system is constructed around the old building, the supporting columns and beams are surrounded and supported by a steel frame structure, and the floor slab adopts a steel truss floor deck structure; The stress ratio of the steel frame structure for the beam body is less than 0.8, and the stress ratio of the steel frame structure for the supporting column is less than 0.75.

[0009] Preferably, in step 2, when analyzing and calculating the structural characteristics of the old building, when calculating the response spectrum of a large earthquake, the structure is analyzed under wind load and various horizontal loads; when calculating the response spectrum of a small earthquake, the torsional coupling effect, accidental eccentricity and bidirectional seismic effect are analyzed.

[0010] Preferably, the wind load adopts a basic wind pressure with a recurrence period of 50 years, the maximum value of the inter-story displacement angle under the action of horizontal force is less than the limit value of 1 / 715, the maximum torsional displacement ratio of the floor is not greater than 1.5, the ratio of the first natural vibration period of torsion to translation is less than 0.9, and the floor shear force / inter-story displacement stiffness is greater than 0.65.

[0011] Preferably, in step five, when repairing the cracks, the static cracks are treated by grouting method, and the active cracks are treated by replacement method.

[0012] Preferably, in step 5, when the board wall is used to reinforce the exterior wall of the old building, an L-shaped tie bar is used to connect the board wall and the original exterior wall; During the construction of exterior walls and panel walls, tie bars are reserved for the steel frame structure with support columns and support beams, and the tie bars are welded to the steel columns and beams.

[0013] Preferably, in step six, when the original roof is dismantled, the removed tiles are classified and stored; when repairing, the main steel beams and secondary steel beams of the drum surface are first installed, and then the steel truss floor decking is installed, the roof eaves and roof panels are cast in place, and finally the original roof tiles are laid to rebuild the roof.

[0014] Preferably, in step six, when repairing the roof, a reinforced concrete roof panel is used for slope leveling, anchor bars are embedded in the panel, and the fine stone concrete or cement mortar leveling layer under the waterproof membrane at the junction of the roof and the protruding roof structure and at the roof downspout is smoothed into an arc with a radius of not less than 50 mm.

[0015] Advantages of the present invention: On the basis of retaining the original exterior walls of the building, the present invention further proposes a new concept of reinforcing beams and columns with a steel frame structure. On the basis of the original load-bearing structure inside the building, a new support system is constructed by partially opening holes and adding beams, plates and columns to complete the overall replacement of the original load-bearing structure of the old building, and then the roof is repaired.

[0016] The beam-slab raft foundation is used to increase the bearing capacity and stability of the foundation, providing operational guarantee for the construction of the steel frame structure. After the cracks on the original wall are repaired, the roof is demolished and repaired to achieve the technical orientation of the renovation and reinforcement of the old community. By rationally interweaving various processes, the exposure time of the old building demolition stage is reduced, and the roof construction is carried out in time to achieve the protective transformation of the landscape building that is "ecological, suitable for tourism, suitable for business, and harmonious".

[0017] The construction method of the present invention is simple to operate and has wide applicability. It can be applied to the protection and utilization of some urban and rural historical and cultural heritage, the renovation of old residential areas, etc. The steel structure occupies less indoor space and has little impact on the foundation of the original structure's exterior wall, and can achieve prefabricated construction, which is green and environmentally friendly. The steel component has a small cross-section and is lighter than reinforced concrete, which is convenient for construction and has a short construction period. The factory-processed steel structure has reliable quality, low overall cost, and is easy to promote. DETAILED DESCRIPTION

[0018] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] Embodiment 1: A steel frame construction method for old building renovation, comprising the following steps: Step 1, conducting a geological survey of the area where the old building to be renovated is located, forming a geological survey report, clarifying the bearing capacity of each soil layer, obtaining the maximum geological foundation load, and ensuring that temporary live loads and newly added frame structures during the renovation construction process will not produce foundation settlement; Simultaneously, drawings of old buildings are drawn to verify the pipeline distribution and usage status of old buildings.

[0020] Step 2: Analyze and calculate the structural characteristics of the old building, and design the steel frame structure system and the reinforcement system of the old building based on the maximum geological foundation load. Use the three-dimensional model technology to calculate and verify the construction sequence and structural load of the steel frame structure system and the reinforcement system of the old building, to ensure that the total load of the steel frame structure system and the reinforcement system of the old building at each construction stage is less than the maximum geological foundation load. Among them, when analyzing and calculating the structural characteristics of old buildings, when calculating the response spectrum of large earthquakes, the structure is analyzed under wind load and various horizontal loads; when calculating the response spectrum of small earthquakes, the torsional coupling effect, accidental eccentricity and bidirectional seismic effect are analyzed; The wind load adopts the basic wind pressure with a return period of 50 years. The maximum value of the inter-story displacement angle under the action of horizontal force is less than the limit value of 1 / 715, the maximum torsional displacement ratio of the floor is not greater than 1.5, the ratio of the first natural vibration period of torsion and translation is less than 0.9, and the floor shear force / inter-story displacement stiffness is greater than 0.65; Reinforcement material selection: The inner wall adopts C30 fine stone slightly expanded concrete, which is self-compacting. The steel performance requirements require that the strength-to-yield ratio of steel should not be less than 1.2, and there should be an obvious yield step. The elongation of steel should be greater than 20%, and it should have good weldability. The load-bearing structure adopts 8.8 grade alloy steel anchor bolts and only rear-expanded bottom anchor bolts or special inverted cone adhesive anchor bolts can be used. The anchor bolts are implanted with Class A anchor glue. The carbon fiber cloth must use small tow fibers of polyacrylonitrile (PAN) below 15K. The repair mortar uses professional high-strength repair mortar with a bonding strength of not less than 2.5MPa. The brick wall protection adopts a special concrete protective agent.

[0021] Step 3: According to the design of the old building reinforcement system, firstly, the pipelines of the old building are dismantled and modified, and then the external blockages, doors and windows, ceilings, and non-load-bearing structures in the old building are dismantled in turn to reduce unnecessary loads for the entire building; Then, the original strip foundation of the old building is used. The beam-slab raft foundation is adopted to reinforce the foundation of the old building without any damage to the original strip foundation of the old building. The original building foundation is used, and the subsequent load is not greater than the original structure load. The settlement of the new structure foundation can be close to zero. Compared with the original building function, the new building plan reduces the load, that is, the inner wall is demolished, and the total mass of the whole building is less than the original building mass. The original building foundation can be used to transfer the column bottom load to the original building inner wall foundation through the beam-slab raft foundation; The construction process of foundation reinforcement treatment is as follows: first layout → arrangement of settlement observation points → determination of foundation pit excavation edge size → foundation excavation on the inner side of the original building outer wall → second layout → opening of inner wall at the foundation beam position → brick membrane masonry → reinforcement of 37 ash soil of the original building → construction of foundation beam cushion layer → tying and lap jointing of steel bars on the inner side of the original building outer wall → tying of foundation beam steel bars → third layout → laying of steel frame embedded slabs → pouring of ground beams → concrete maintenance → foundation backfill; Among them, the arrangement of settlement observation points: Set settlement observation points every 10m on the 1m line of the exterior wall structure of the old building, and must be set at the corners (yin and yang corners). The calibration points required for observation are set outside the building that is not demolished and renovated outside the 20-meter range; mark the outline of the foundation structure column on the indoor plane according to the axis position, and expand it 500mm to leave a foundation pit excavation construction surface. At the same time, according to the 1m line of the structure, accurately excavate to the specified depth, and do not over-excavate; Second setting out: After the excavation of the foundation pit is completed, the scope of the foundation 37 ash soil reinforcement and the foundation beam are set out for the second time according to the structural drawing; Opening holes in the inner wall at the foundation beam location: For reserved openings with a width not exceeding 300mm, lintel support may not be provided. For openings with a width exceeding 300mm, angle steel supports shall be provided at the mortar joints on both sides of the inner wall before opening the opening, and the support on each side shall not be less than 250mm in the width direction of the opening. The inner and outer wall angle steels shall be removed 7 days after the foundation beam is poured and cured. After the support is set, use static cutting equipment to open the hole for the ground beam; On the inner side of the 37-grain soil foundation of the original building's outer wall, C20 plain concrete is used to reinforce the foundation to expand the bearing capacity of the original building's foundation, and then the inner side of the original building's outer wall and the upper foundation beam are reinforced; The third time of laying out: After the foundation beam reinforcement is tied, the steel frame column embedded plate position is laid out to ensure the accuracy of the plane position and horizontal elevation of the steel frame column embedded plate. When laying the embedded plate, use wire tying and spot welding to fix it firmly to prevent the embedded plate from shifting during concrete pouring; After the foundation beam reinforcement binding and steel frame column embedded slabs are accepted, concrete pouring is carried out.

[0022] Step 4: Based on the design of the steel frame structure system, a steel frame structure system is constructed on the basis of the reinforcement treatment around the old building to provide auxiliary support for the old building; during transportation and storage, corresponding measures should be taken to prevent deformation of the steel structure parts; Among them, the supporting columns and beams of the old buildings are all surrounded and supported by steel frame structures. The frame beams and columns are designed to be non-yielding in medium earthquakes and elastic enveloping in small earthquakes. The floor slabs are made of reinforced truss floor deck structures. The stress ratio of the steel frame structure for the beams is less than 0.8, and the stress ratio of the steel frame structure for the supporting columns is less than 0.75. During transportation and storage, appropriate measures should be taken to prevent deformation of steel structures. The installation method and sequence of steel structures should be determined according to the structural characteristics, construction site conditions, etc. During installation, a stable spatial stiffness unit should be formed. During measurement and correction, the effects of temperature, sunlight, and welding deformation on structural deformation should be considered.

[0023] Step 5: According to the design of the old building reinforcement system, the exterior walls of the old buildings are reinforced with board walls and the cracks in the walls are repaired; Among them, when repairing cracks, static cracks are treated by grouting, using non-shrinkage cement grouting materials, epoxy-based grouting materials, etc.; active cracks, weathering, and erosion areas with more serious cracks are treated by replacement method; When the board wall is used to reinforce the exterior wall of the old building, the board wall thickness is 100mm, and C30 slightly expanded fine stone concrete is used through self-compacting to effectively avoid the problem of inadequate concrete vibration measures; the board wall and the original exterior wall are connected by L-shaped tie bars; when constructing the exterior wall and board wall, tie bars are reserved for the steel frame structure of the supporting columns and supporting beams, with a tie bar spacing of 200mm, and the tie bars are welded to the steel columns and steel beams; Among them, the layered formwork and layered pouring method is adopted during the board wall reinforcement construction. The original one-time pouring of a single room is changed to three-time pouring, which reduces the one-time concrete pouring amount, ensures the external vibration effect, and effectively prevents the phenomenon of insufficient vibration of concrete reinforcement wall; the use of self-compacting fine stone concrete can effectively avoid inadequate concrete vibration measures; the indoor wall casting adopts the pumping method, and by increasing the number of fixed pump pipes, the time used for moving the fixed pump pipe during the concrete pouring of the reinforced wall can be effectively shortened, thereby improving the concrete pouring efficiency; combined with the indoor structure distribution of the original building, holes are opened in advance for the indoor wall panels that affect the movement of the pump pipe, which reduces the time for pump pipe installation and ensures the fluidity of the concrete.

[0024] Step 6: According to the design of the old building reinforcement system, the old building roof is protectively dismantled, repaired and rebuilt; The specific steps of roof removal are: brick flue removal → tile protective removal → tile bonding mortar, wooden purlins, and wooden purlins removal → wooden roof frame removal; The steps of roof reconstruction are: first install the main steel beams and secondary steel beams of the drum surface, then install the steel truss floor deck, use the cast-in-place process for the roof eaves and roof panels, and finally lay the original roof tiles to rebuild the roof; Specifically, the reinforced concrete roof panel is used for slope leveling, anchor bars are embedded in the roof panel (Ф10@900×900mm steel bars, extending 30mm from the thermal insulation layer, and the depth of the steel bars embedded in the panel is 80mm) → leveling layer construction (leveling layer 20mm thick 1:2.5 cement mortar) → laying the first layer of waterproof coating (the first layer of waterproof coating uses 2.0mm thick non-curing rubber asphalt, and the places above the roof such as roof pipes and flues must be turned up, and the turning height must not be less than 300mm from the finished surface) → second layer of waterproof material (the second layer of waterproof material uses Use 3.0mm thick SBSП, and lay it on the waterproof materials above the roof such as the roof pipes and flues, and the height of the upturn shall not be less than 300mm from the finished surface) → Insulation layer (100mm thick extruded polystyrene board B1 grade) → Clean, inspect and repair → Insulation layer acceptance → Lay the horizontal tile layer (using 1:3 cement mortar), the thinnest part of the horizontal tile layer is ≥20mm (with Ф6@500×500mm steel mesh inside and the roof panel embedded with Ф10mm steel bar head) → Lay the original tiles (clean and repair the original tiles in advance); The fine stone concrete or cement mortar leveling layer under the waterproof membrane at the junction of the roof and the protruding roof structure and at the roof downspout is smoothed into an arc with a radius of not less than 50mm; When pouring a new roof, the entire roof is divided into 4 construction areas according to units. Expansion joints are set every 6m in both directions of each construction area. Different construction areas are poured in sequence.

[0025] Embodiment 2: A steel frame construction method for old building reconstruction. The difference between this embodiment and embodiment 1 is that in step 6, the tie bars reserved on the wall are welded to the newly built steel frame structure during the beam and column construction. The welding connection process adopts the skipping method, and the welding connection is performed in a skipping construction mode. After the temperature drops, secondary welding is performed to avoid excessive deformation of the steel frame caused by local high temperature welding. The other methods are the same as embodiment 1.

[0026] Example 3: A steel frame construction method for old building reconstruction. The difference between this example and Example 1 is that before the wall is planted with reinforcement, a φ8mm small hollow water drill is used instead of an ordinary spiral drill to perform the drilling operation before the reinforcement is planted in the original building brick wall, thereby reducing the damage to the original building brick body caused by the reinforcement. The other methods are the same as Example 1.

[0027] Embodiment 4: A steel frame construction method for old building reconstruction. The difference between this embodiment and embodiment 1 is that the board wall reinforcement adopts the method of pouring in batches, and the template used for supporting the formwork is provided with a φ10mm observation hole every 300mm in the horizontal direction, so as to facilitate the observation and control of the concrete pouring height. The other methods are the same as those in embodiment 1.

[0028] Embodiment 5: A steel frame construction method for old building reconstruction, the difference between this embodiment and embodiment 1 is that the force-bearing support rods for the board wall reinforcement used for the formwork are opened in advance in the inner partition wall perpendicular to the original building outer wall, which is convenient for the installation and fixation of the rods, and cooperates with the inclined support fixed on the hollow floor of the original building to ensure the force stability of the board wall reinforcement formwork. Other methods are the same as embodiment 1.

[0029] It is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be regarded as exemplary and non-restrictive from all points of view, and the scope of the present invention is limited by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention.

Claims

1. A steel frame construction method for old building reconstruction, characterized in that: The following steps are involved: Step 1: Conduct geological surveys on the area where the old building to be renovated is located, form a geological survey report, and obtain the maximum geological foundation load; Step 2: Analyze and calculate the structural characteristics of the old building, and design the steel frame structure system and the reinforcement system of the old building based on the maximum geological foundation load. Use the three-dimensional model technology to calculate and verify the construction sequence and structural load of the steel frame structure system and the reinforcement system of the old building, to ensure that the total load of the steel frame structure system and the reinforcement system of the old building at each construction stage is less than the maximum geological foundation load. Step 3: Based on the design of the old building reinforcement system, the original strip foundation of the old building is used, and the beam-slab raft foundation is used to reinforce the foundation of the old building without any damage to the original strip foundation of the old building. Step 4: Based on the design of the steel frame structure system, a steel frame structure system is constructed on the basis of the reinforcement treatment around the old building to provide auxiliary support for the old building; Step 5: According to the design of the old building reinforcement system, the exterior walls of the old buildings are reinforced with board walls and the cracks in the walls are repaired; Step six: Based on the design of the old building reinforcement system, the roof of the old building is protectively dismantled, repaired and rebuilt.

2. A steel frame construction method for old building reconstruction as claimed in claim 1, characterized in that: In step 1, while conducting geological survey, drawings of old buildings are simultaneously drawn to check the distribution and usage of pipelines in old buildings; In step three, before reinforcing the foundation of the old building, the pipelines of the old building are first dismantled and modified.

3. A steel frame construction method for old building reconstruction as claimed in claim 1, characterized in that: Before carrying out the foundation reinforcement treatment of the old building in step three, first remove the external blockages inside the old building, then remove the doors and windows, ceilings, and finally remove the non-load-bearing structures.

4. A steel frame construction method for old building reconstruction as claimed in claim 1, characterized in that: In step 4, when constructing a steel frame structure system around the old building, the supporting columns and beams are surrounded and supported by the steel frame structure, and the floor slab adopts a steel truss floor deck structure; The stress ratio of the steel frame structure for the beam body is less than 0.8, and the stress ratio of the steel frame structure for the supporting column is less than 0.

75.

5. A steel frame construction method for old building reconstruction as claimed in claim 1, characterized in that: In step 2, when analyzing and calculating the structural characteristics of the old building, when calculating the response spectrum of a large earthquake, the structure is analyzed under wind loads and various horizontal loads; when calculating the response spectrum of a small earthquake, the torsional coupling effect, accidental eccentricity and bidirectional seismic effects are analyzed.

6. A steel frame construction method for old building reconstruction as claimed in claim 5, characterized in that: The wind load adopts the basic wind pressure with a recurrence period of 50 years. The maximum value of the inter-story displacement angle under the action of horizontal force is less than the limit value 1 / 715, the maximum torsional displacement ratio of the floor is not greater than 1.5, the ratio of the first natural vibration period of torsion and translation is less than 0.9, and the floor shear / inter-story displacement stiffness is greater than 0.

65.

7. A steel frame construction method for old building reconstruction as claimed in claim 1, characterized in that: In step five, when repairing the cracks, the static cracks are treated by grouting method, and the active cracks are treated by replacement method.

8. A steel frame construction method for old building reconstruction as claimed in claim 1, characterized in that: In step 5, when the board wall is used to reinforce the exterior wall of the old building, the board wall and the original exterior wall are connected by L-shaped tie bars; During the construction of exterior walls and panel walls, tie bars are reserved for the steel frame structure with support columns and support beams, and the tie bars are welded to the steel columns and beams.

9. A steel frame construction method for old building reconstruction as claimed in claim 1, characterized in that: In step six, when the original roof is dismantled, the removed tiles are classified and stored; when repairing, the main steel beams and secondary steel beams of the drum surface are installed first, and then the steel truss floor decking is installed, the roof eaves and roof panels are cast in place, and finally the original roof tiles are laid to rebuild the roof.

10. A steel frame construction method for old building reconstruction as claimed in claim 9, characterized in that: In step six, when repairing the roof, reinforced concrete roof panels are used for slope leveling, anchor bars are embedded in the panels, and the fine stone concrete or cement mortar leveling layer under the waterproof membrane at the junction of the roof and the protruding roof structure and at the roof downspout is smoothed into an arc with a radius of not less than 50 mm.