LU506025B1 - A novel method for producing permanent concrete columns using prefabricated angle steel grid formwork - Google Patents
A novel method for producing permanent concrete columns using prefabricated angle steel grid formwork Download PDFInfo
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- LU506025B1 LU506025B1 LU506025A LU506025A LU506025B1 LU 506025 B1 LU506025 B1 LU 506025B1 LU 506025 A LU506025 A LU 506025A LU 506025 A LU506025 A LU 506025A LU 506025 B1 LU506025 B1 LU 506025B1
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- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 118
- 239000010959 steel Substances 0.000 title claims abstract description 118
- 238000009415 formwork Methods 0.000 title claims abstract description 91
- 239000004567 concrete Substances 0.000 title claims abstract description 75
- 238000004519 manufacturing process Methods 0.000 title claims description 14
- 239000011374 ultra-high-performance concrete Substances 0.000 claims abstract description 44
- 238000000034 method Methods 0.000 claims abstract description 31
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 15
- 238000013461 design Methods 0.000 claims description 15
- 238000012360 testing method Methods 0.000 claims description 12
- 239000002131 composite material Substances 0.000 claims description 9
- 239000004576 sand Substances 0.000 claims description 9
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 8
- 239000000203 mixture Substances 0.000 claims description 7
- 239000000843 powder Substances 0.000 claims description 7
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 claims description 6
- 239000000835 fiber Substances 0.000 claims description 5
- 238000012423 maintenance Methods 0.000 claims description 5
- 230000003014 reinforcing effect Effects 0.000 claims description 5
- 229910000019 calcium carbonate Inorganic materials 0.000 claims description 3
- 238000005056 compaction Methods 0.000 claims description 3
- 239000011241 protective layer Substances 0.000 claims description 3
- 239000004568 cement Substances 0.000 claims description 2
- 239000003638 chemical reducing agent Substances 0.000 claims description 2
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 claims 1
- 229910052791 calcium Inorganic materials 0.000 claims 1
- 239000011575 calcium Substances 0.000 claims 1
- 229910021487 silica fume Inorganic materials 0.000 claims 1
- 239000007787 solid Substances 0.000 claims 1
- 238000010276 construction Methods 0.000 abstract description 38
- 239000000463 material Substances 0.000 abstract description 5
- 230000008569 process Effects 0.000 abstract description 3
- 230000002787 reinforcement Effects 0.000 abstract 1
- 230000006835 compression Effects 0.000 description 8
- 238000007906 compression Methods 0.000 description 8
- 238000005516 engineering process Methods 0.000 description 5
- 239000006004 Quartz sand Substances 0.000 description 4
- 230000008901 benefit Effects 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 230000002708 enhancing effect Effects 0.000 description 3
- 239000002699 waste material Substances 0.000 description 3
- 238000003466 welding Methods 0.000 description 3
- 239000002023 wood Substances 0.000 description 3
- 239000011230 binding agent Substances 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- 230000007613 environmental effect Effects 0.000 description 2
- 230000003116 impacting effect Effects 0.000 description 2
- 239000002985 plastic film Substances 0.000 description 2
- 229920006255 plastic film Polymers 0.000 description 2
- 238000002360 preparation method Methods 0.000 description 2
- 230000001737 promoting effect Effects 0.000 description 2
- 239000010453 quartz Substances 0.000 description 2
- 230000002411 adverse Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000005266 casting Methods 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 238000006073 displacement reaction Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000004134 energy conservation Methods 0.000 description 1
- 238000003912 environmental pollution Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 239000010410 layer Substances 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 239000012528 membrane Substances 0.000 description 1
- 230000000116 mitigating effect Effects 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 238000005457 optimization Methods 0.000 description 1
- 238000009417 prefabrication Methods 0.000 description 1
- 230000002028 premature Effects 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 238000003908 quality control method Methods 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 239000011150 reinforced concrete Substances 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 239000002002 slurry Substances 0.000 description 1
- 239000004575 stone Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
- 230000007306 turnover Effects 0.000 description 1
Classifications
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B28/00—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
- C04B28/02—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing hydraulic cements other than calcium sulfates
- C04B28/04—Portland cements
-
- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04C—STRUCTURAL ELEMENTS; BUILDING MATERIALS
- E04C3/00—Structural elongated elements designed for load-supporting
- E04C3/30—Columns; Pillars; Struts
- E04C3/34—Columns; Pillars; Struts of concrete other stone-like material, with or without permanent form elements, with or without internal or external reinforcement, e.g. metal coverings
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2201/00—Mortars, concrete or artificial stone characterised by specific physical values
- C04B2201/50—Mortars, concrete or artificial stone characterised by specific physical values for the mechanical strength
- C04B2201/52—High compression strength concretes, i.e. with a compression strength higher than about 55 N/mm2, e.g. reactive powder concrete [RPC]
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Architecture (AREA)
- Structural Engineering (AREA)
- Ceramic Engineering (AREA)
- Civil Engineering (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Inorganic Chemistry (AREA)
- Materials Engineering (AREA)
- Organic Chemistry (AREA)
- On-Site Construction Work That Accompanies The Preparation And Application Of Concrete (AREA)
Abstract
This invention discloses a method and apparatus for utilizing precast angle steel grid permanent formwork concrete columns. It tackles the challenge of controlling construction quality during on-site binding, pouring of concrete columns. Simultaneously, as a method for prefabricated construction, its introduction streamlines the construction process, minimizes resource wastage in terms of labor and materials, and significantly enhances construction efficiency. The permanent formwork for concrete columns in this invention employs prefabricated angle steel embedded at the four corners, steel connecting plates, and ultra-high-performance concrete (UHPC). This setup provides a portion of the load-bearing capacity for the column structure. During subsequent assembly-type pouring, the concrete type can be chosen based on the component's designed load-bearing capacity. If necessary, a reinforcement cage can also be internally configured. The connection method for the precast angle steel grid permanent formwork concrete columns, as outlined in this invention, is currently suitable only for multi-story building structures.
Description
DESCRIPTION LU506025
A NOVEL METHOD FOR PRODUCING PERMANENT CONCRETE COLUMNS
USING PREFABRICATED ANGLE STEEL GRID FORMWORK
[0001] The present invention relates to the field of composite column technology, particularly to a novel method for producing permanent concrete columns using prefabricated angle steel grid formwork.
[0002] With the development of China's economy and construction technology, the construction industry has entered a period of transformation and upgrading. The modernization of the construction industry has highlighted the inevitability and importance of structural reforms in the supply side of the construction industry in various aspects such as technology and industry. Among these, the choice and implementation of the mode for constructing prefabricated component production bases for assembled buildings have significant research and practical significance for rapidly advancing and implementing the industrialization of the construction industry.
[0003] Regarding formwork engineering, traditional formwork mainly consists of wooden formwork and steel formwork. Although they can meet construction demands, dismantling these formworks is very cumbersome. According to statistics, in the construction of cast-in-place concrete structures, the formwork consumption is as high as 4 to 5 square meters per 1 square meter of concrete work, accounting for approximately one-third of the cost of cast-in-place concrete structures, and labor and time account for about half. The permanently embedded angle steel grid formwork involved in this invention can significantly reduce the demand for materials such as wood, simplifying on-site formwork removal, steel bar binding, and other construction procedures. Prefabricated steel components used for connecting columns between columns can also improve construction site work efficiency, ensure connection quality, and meet the environmental protection requirements of today's green construction.
[0004] The new type of embedded angle steel concrete column structure refers {9,506025 replacing the longitudinal bars in a traditional concrete column structure with rigid angle steel, and using steel plate hoops welded to the longitudinal angle steel instead of the ties in a traditional concrete column structure, forming a new structure composed of spatial steel framework and concrete. The advantage of this structure lies in the relatively simple internal steel framework construction in the concrete column and the ease of setting embedded parts. Simultaneously, the steel framework can be prefabricated in the factory, effectively reducing on-site construction for steel bar binding tests, and improving the overall quality of components.
[0005] Ultra-high-performance concrete (UHPC) is a new type of cement-based composite material with characteristics such as ultra-high strength, ultra-high toughness, relatively stable volume, and excellent durability. The use of ultra-high-performance concrete has a significant impact on improving the quality of buildings, effectively extending their service life, and enhancing disaster prevention and mitigation capabilities. It is suitable for China's current advocacy of energy conservation, emission reduction, and sustainable development principl
[0006] To avoid the issues of significant input of support formwork, low turnover utilization of formwork materials, high labor input, generation of substantial construction waste, and low construction efficiency in traditional formwork engineering, the present invention provides a novel method for producing permanent concrete columns using prefabricated angle steel grid formwork. This method simplifies on-site formwork removal, steel bar binding, and other construction procedures, achieving the production of new-type permanent non-dismantling formwork prefabricated components that are green and highly efficient, effectively addressing the existing problems in current formwork construction technology.
[0007] Technical Solution
[0008] The present invention proposes a method for producing permanent concrete columns using prefabricated angle steel grid formwork, including the angle steel 2 embedded in the permanent formwork, steel connecting plates 3 between angle steels, welding seams 4 connecting angle steels and connecting plates, UHPC (Ultra-High-Performance Concrete) 1 used for prefabricated permanent formwork, and internally filled plain concrete 5.
[0009] A method for producing permanent concrete columns using prefabricated,596025 angle steel grid formwork comprises the following steps:
[0010] Step one, preparing the required UHPC for prefabricated permanent formwork, determining the optimal mechanical performance of UHPC through tests such as cube compressive strength, compressive modulus of elasticity, flexural strength, etc.
For further cost optimization, this invention substitutes traditional quartz sand with ordinary washed river sand, having an apparent density of 2.62g/cm3, a fineness modulus of 2.6, sand content of 0.2%, and adjusts quartz powder to 400-mesh heavy calcium carbonate powder.
[0011] Step two, determining the dimensions of the rigid connecting plates 3 in the embedded angle steel composite structure of permanent formwork through load-bearing capacity calculations.
[0012] Step three, constructing the angle steel grid structure on a bottom plate made of square steel plates, placing angle steels 2 at the four corners of the column, calculating the required length of angle steels according to structural requirements, and leaving the necessary length for connections.
[0013] Step four, welding steel connecting plates 3 between angle steels according to the calculated dimensions and quantity from step one.
[0014] Step five, supporting the external formwork and internal membrane of the permanent formwork, leaving a 20mm protective layer thickness; the formwork thickness is determined by the calculated cross-sectional area dimensions of the embedded angle steel composite structure under actual load-bearing conditions.
[0015] Step six, using a horizontal axis forced mixer or a new type of mixer such as counter-current or planetary mixer to mix the ultra-high-performance concrete (UHPC) used in the formwork and pouring it.
[0016] Step seven, curing the angle steel grid formwork; due to the different properties of UHPC from ordinary concrete regarding shrinkage and creep, enhanced curing is necessary during construction, especially early wet curing; for the column permanent formwork described in the present invention, it requires early dismantling and curing.
[0017] Step eight, pouring ordinary concrete 5 inside the permanent formwork.
[0018] The present invention proposes a prefabricated connection method for constructing permanent concrete columns using prefabricated angle steel grid formwork.
The primary method involves connecting the angle steel in the upper and low@{,506025 concrete columns to prefabricated steel components using high-strength bolts. The main structures include: reserved bolt holes 7-13 in the concrete column angle steel and steel components, prefabricated steel component side face steel plates 16, reinforcing ribs 14, inside the prefabricated steel component side face, and internal reinforcing ribs 17 within the prefabricated steel component.
[0019] A prefabricated connection method for constructing permanent concrete columns using prefabricated angle steel grid formwork includes the following steps:
[0020] Step one, using the previously described method, connect the completed lower column poured according to the reserved angle steel and its bolt holes 7-13 to the prefabricated steel structural connector using high-strength bolts, corresponding sequentially to the numbered illustration.
[0021] Step two, connect the upper column of the UHPC permanent formwork structure with reserved angle steel and its bolt holes to the prefabricated steel structural connector using high-strength bolts.
[0022] Step three, completely pour ordinary concrete 5 into the upper column and the interior of the prefabricated rigid structural connector and thoroughly vibrate.
[0023] Step four, use concrete to smooth the joint between the upper and lower columns and the rigid components, forming a cohesive structure.
[0024] Step five, perform curing on the internal concrete.
[0025] Advantages: The method for constructing permanent concrete columns using prefabricated angle steel grid formwork proposed in this invention, compared to existing technology, presents the following technical advantages:
[0026] 1. The method significantly improves the construction efficiency of formwork engineering in construction by eliminating cumbersome processes like supporting and dismantling formwork, making construction more industrialized and modern.
[0027] 2. It effectively alleviates construction waste issues on construction sites. The permanent non-dismantling formwork proposed in this invention differs from traditional formwork, promoting green construction practices, reducing environmental pollution, and minimizing waste of wood resources in traditional wood formwork construction.
[0028] 3. The method for constructing permanent concrete columns UsiNg,506025 prefabricated angle steel grid formwork, as proposed in this invention, effectively streamlines the construction process during subsequent concrete pouring, enhancing construction efficiency while boasting environmental friendliness, ease of operation, and high energy efficiency.
[0029] 4. Due to the prefabrication of the formwork in the factory, with fewer uncontrollable factors on-site, the method in this invention results in higher production precision, lower errors compared to on-site construction, making subsequent installation easier and more aligned with structural design, thereby benefiting quality control in construction.
[0030] 5. The method for constructing permanent concrete columns using prefabricated angle steel grid formwork, as described in this invention, significantly increases the compressive strength of concrete columns due to the use of ultra-high-performance concrete and angle steel grid structure in the permanent formwork, promoting material and structural design savings.
[0031] 6. The construction connection method for prefabricated angle steel grid formwork columns, as described in this invention, is easily implementable at the construction site, saving labor and technical requirements, ensuring construction quality to a greater extent, and enhancing construction speed.
[0032] Preferably, when producing the embedded angle steel grid formwork, a section of angle steel should be reserved according to the design column height and bolt holes 7-13 should be set for subsequent connections.
[0033] Preferably, when mixing the ultra-high-performance concrete (UHPC) inside the permanent formwork, a horizontal axis forced mixer or a new type of mixer such as a counter-current or planetary mixer should be used.
[0034] Preferably, during the vibration of the ultra-high-performance concrete (UHPC) inside the permanent formwork, a high-frequency vibrator should be used for thorough vibration.
[0035] Preferably, for pouring the pre-mixed ultra-high-performance concrete (UHPC) inside the formwork, a flat pouring method is chosen, as described in this invention.
[0036] Preferably, to reduce costs, ordinary washed river sand is used instead of quartz sand in the ultra-high-performance concrete (UHPC) inside the permanent formwork.
[0037] Preferably, high-strength bolts are used for the connection between UPPe{,506025 and lower columns.
[0038] The accompanying drawings, which form a part of this application, are used to provide a further understanding of the invention, and the illustrative embodiments of the invention and their descriptions are used to explain the invention, and do not constitute an undue limitation of the invention.
[0039] Fig. 1 is a top sectional view of a concrete column with prefabricated angle steel lattice permanent formwork according to the present invention.
[0040] Fig. 2 is a front sectional view of a permanent formwork in a concrete column using prefabricated angle steel lattice permanent formwork according to the present invention.
[0041] Figure 3 is an overall structural diagram of the connection method of concrete columns with prefabricated angle steel lattice permanent formwork according to the present invention.
[0042] Fig. 4 is a side elevation view of precast steel connectors in the connection method of concrete columns with precast angle steel lattice permanent formwork according to the present invention.
[0043] Fig. 5 is a front elevation view of prefabricated steel connectors in the connection method of concrete columns with prefabricated angle steel lattice permanent formwork according to the present invention. wherein, 1- UHPC (Ultra-High-Performance Concrete) 2- Embedded angle steel in the permanent formwork 3- Steel connecting plates of the grid structure in the permanent formwork 4- Connection by welding between the connecting plates and angle steel 5-
Ordinary concrete inside the permanent formwork 6- Angle steel reserved for subsequent column-to-column connections 7-13- Reserved bolt holes in the concrete column angle steel and steel components 16- Side face steel plates of prefabricated steel components 14, 15- Reinforcing ribs inside the prefabricated steel component's front face 17- Internal reinforcing ribs of the prefabricated steel component
DETAILED DESCRIPTION OF THE INVENTION LU506025
[0045] Below, in combination with the accompanying drawings, further detailed explanations of specific embodiments of the present invention are provided: [0046] |.
Preparation of the required UHPC (Ultra-High-Performance Concrete) for prefabricated permanent formwork: [0047] The optimal mix ratio of UHPC was determined through tests on mechanical properties such as cube compressive strength, compressive modulus of elasticity, and flexural strength. In order to further optimize and reduce material costs, the present invention substituted traditional quartz sand with ordinary washed river sand, having an apparent density of 2.63g/cm3, a fineness modulus of 2.5, and a sand content of 0.2%. Additionally, the quartz powder was adjusted to 400-mesh heavy calcium carbonate powder. [0048] After preparation, UHPC was designed according to the mix ratio in Table 1 to create 100mm cube specimens. Cube compressive strength tests were conducted using a hydraulic servo testing machine, resulting in an average compressive strength of 130MPa for UHPC. [0049] Excessive fiber content can affect the flexural strength of UHPC, and an excessive amount of steel fibers can reduce the flowability of UHPC, making pouring and mixing significantly more challenging, thereby impacting the quality of the finished components. Therefore, it is advisable to moderately reduce the fiber rigidity proportion. Additionally, the elastic modulus of UHPC has a significant relationship with the water-binder ratio. Experimental results showed that under the same fiber content conditions, specimens with lower water-binder ratios had higher elastic modulus.
Table 1 Mix ratio of UHPC fum powder sand steel reducer
[0052] 2. Manufacture of the UHPC permanent template with built-in angle steel lattice composite structure;
[0053] Step 1: Calculate the size of the rigid batten plate 3 in the permanent formwork of the built-in angle steel composite structure through the design bearing capacity;
[0054] In the present invention, because steel battens are equivalent to stirrups jn,596025 ordinary column members, the minimum stirrup ratio of members is calculated according to the characteristic value of minimum stirrup ratio of design axial compression ratio under different seismic grades specified in Code for Design of Concrete Structures, so as to determine the size and quantity of steel battens in members; In this invention, the design axial compression ratio and the test axial compression ratio are obtained by conversion. By consulting relevant literature, the conversion relationship between them is: Na = 2. 14No, where nd is the design axial compression ratio; No is the test axial compression ratio; The experimental axial compression ratio is calculated by the expression of axial compression ratio of ordinary reinforced concrete columns specified in Code for Design of Concrete Structures (GB50011) and Code for Seismic Design of
Buildings (GB50011).
[0055] By observing the model column method to calculate the load-displacement (p- A) relationship of the specimen, it is concluded that when the experimental axial compression ratio no, the axial compressive strength design value fc, the steel ratio Ps, the yield strength fy and the shear span ratio A are constant, the p-A curve under different stirrup ratios can be obtained, which has little influence on the bearing capacity of the building, but has a great role in improving the ductility of the building; Therefore, the
UHPC permanent formwork with built-in angle steel lattice combined structure can appropriately increase the stirrup ratio to improve the ductility of the structure;
[0056] Step Two: Create a combined structural framework using angle steel on the bottom plate made of square steel, positioning angle steel 2 at the four corners of the column, calculating the required length of angle steel according to structural requirements, and leaving additional length for the necessary connection.
[0057] Step Three: Based on the calculated dimensions and quantity of the connecting plates in Step One, weld the steel connecting plates 4 between the angle steel as shown in the diagram.
[0058] Step Four: Support the outer mold and inner film of the permanent formwork, leaving a 20mm protective layer. The thickness of the formwork is determined by the cross-sectional area dimensions of the internal angle steel structure calculated based on the actual load-bearing capacity.
[0059] Step Five: Utilize a horizontal-axis forced mixer, counterflow mixer, or planetary mixer to mix the Ultra-High Performance Concrete (UHPC) used inside the formwork.
[0060] When pouring the UHPC prepared inside the formwork, two methods can bg)506025 used: flat pouring and narrow pouring. Given the excellent fluidity and self-leveling properties of UHPC, this invention chooses the flat pouring method to achieve a smoother and denser appearance of the component.
[0061] Step Six: Employ a high-frequency vibrating device to fully vibrate the UHPC within the angle steel framework of the permanent formwork.
[0062] Step Seven: Perform maintenance on the permanent formwork composed of angle steel structures. Due to the difference in shrinkage and creep properties between
UHPC and ordinary concrete, stronger maintenance is required during construction, especially in early-stage moist curing. For the column permanent formwork described in this invention, an early demolding and maintenance are necessary. High-temperature curing is advantageous for increasing the component's density due to the pozzolanic reaction in UHPC. Considering the use of admixed Ultra-High Performance Concrete, the curing time should not be less than 14 days, maintaining the internal concrete temperature below 75°C, with measures to prevent a temperature difference greater than 25°C between the interior and exterior of the test specimens. Initially, misting is preferred over water sprinkling during early-stage curing to avoid adverse effects such as concrete cracking caused by significant temperature differences inside and outside the concrete. For the components using the combined structure of internal angle steel and UHPC, a curing box is used for 90°C hot water curing, with specific measures: (1) demold after stationary indoor placement for 1 day after casting completion; (2) apply hot water curing using a curing box for 2 days; (3) standard indoor curing at room temperature for 28 days.
[0063] In actual implementation, the load-bearing capacity of the prefabricated angle steel permanent formwork concrete column in this invention is closely related to the strength of the steel and the internal concrete. Therefore, suitable steel grades and concrete strength levels need to be selected based on the design load-bearing capacity of the overall structure.
[0064] In practical implementation, to prevent premature shear failure of components, it is necessary to adjust the shear span ratio of the structure according to the actual design size requirements. A=M/(VhO), where M is the moment at the end of the frame column, V is the shear force at the end of the frame column, and hO is the effective height of the column section parallel to the moment M.
It is generally known that the reasonable configuration of stirrups (and the stegl,506025 connecting plates in this invention) can effectively adjust the overall shear span ratio of the component.
[0065] Three: Pouring ordinary concrete inside the permanent formwork;
[0066] Since the cross-sectional area of the external permanent formwork is relatively small, quartz sand is used in place of stone in the internal poured concrete to ensure the integrity of the test specimens and the sufficient load-bearing capacity of the column specimens. The concrete strength level is selected based on the actual design load-bearing capacity requirement.
[0067] During concrete pouring, avoid dumping and impacting the formwork; when the height exceeds 2 meters, use a chute to feed the concrete gradually. The free fall height from the discharge pipe mouth to the pouring layer should not exceed 1.5 meters, and the concrete must be poured within five hours.
[0068] During pouring, the vibrating duration should ensure the production of slurry on the concrete surface, with no air bubbles, until there is no sinking. The vibrating device should be inserted evenly in a floral pattern, moving in a matrix sequence, with the distance between positions not exceeding 40cm to ensure no missed vibrations or excessive vibrations.
[0069] After second and third surface compactions of the concrete, cover it immediately. After the concrete reaches its final setting, first wet it thoroughly with water, then seal it with plastic film. Regularly check the surface of the plastic film. If there are no water droplets on the film surface, water should be sprinkled again. The curing time should not be less than 7 days.
[0070] Four: The invention also includes a method for connecting prefabricated angle steel permanent formwork concrete columns during construction;
[0071] Step One: Use high-strength bolts to connect the lower column, completed according to the above method, with the reserved angle steel and its bolt holes 7-13 to the prefabricated steel structural connector, ensuring a one-to-one correspondence with the numbered connections in the diagram.
[0072] Step Two: Connect the upper column of the UHPC permanent formwork, which has not yet been poured with ordinary concrete, using the reserved angle steel and its bolt holes with the prefabricated steel structural connector through high-strength bolts.
[0073] Step Three: Pour ordinary concrete 5 entirely into the upper column and th&,506025 precast rigid structural connection elements from the top of the upper column and vibrate sufficiently.
[0074] Step Four: Use concrete to flatten the connection between the upper and lower columns' rigid components on the side and front faces, creating a unified appearance between the upper and lower columns and the connection points.
[0075] Step Five: Perform maintenance on the internal concrete.
[0076] The specific embodiment described above further details the purpose, technical scheme and beneficial effects of the present invention; It should be understood that the above is only a specific embodiment of the invention, and it is not used to limit the invention. Any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the invention should be included in the protection scope of the invention.
Claims (4)
1. Method for producing a prefabricated angle steel grid permanent formwork concrete column, including the following steps: step 1: prepare ultra-high-performance concrete required for the prefabricated permanent formwork; determine the optimal mix ratio of ultra-high-performance concrete by testing its mechanical properties, including compressive strength and modulus of elasticity; the fine sand used is washed river sand with an apparent density of 2.62g/cm°, a fineness modulus of 2.6, 0.2% silt content, and 400-mesh heavy calcium carbonate powder; mix ratio of ultra-high-performance concrete: cement: 1 silica fume: 0.24 calcium powder: 0.31 fine sand: 1.0 water: 0.22 steel fiber: 0.016 water reducing agent: 0.037 once prepared, design and create cubic test blocks according to the mix ratio; conduct compressive strength tests on the cubic blocks, obtaining an average compressive strength of 130MPa for the ultra-high-performance concrete; step 2: calculate the dimensions and quantity of steel patch plates (3) in the permanent formwork according to the designed load-bearing capacity; step 3: construct an internal angle steel grid composite structure on the bottom plate made of square steel plates; place angle steels (2) at the four corners of the column, calculating the required length based on structural requirements and leaving a length for connection; step 4: weld steel patch plates (3) between the angle steels based on the dimensions and quantity calculated in step 2; step 5: support the outer and inner molds of the permanent formwork, leaving a 20mm protective layer thickness; determine the mold thickness based on the sectional dimensions of the internal angle steel grid composite structure configured under actual load-bearing conditions; step 6: mix and pour ultra-high-performance concrete (1) using a forced horizontal shaft mixer or counter-current/planetary mixer inside the formwork;
step 7: cure the permanent formwork, demold after 1 day indoors, perform hot wat@{,506025 curing for 2 days using a curing box, followed by standard indoor curing at room temperature for 28 days; step 8: pour ordinary concrete inside the permanent formwork.
2. According to claim 1, a method for producing a prefabricated angle steel grid permanent formwork concrete column: the permanent formwork pouring of ultra-high-performance concrete (1) is done using flat pouring methods, ensuring thorough compaction and maintenance; the internal ordinary concrete strength should be calculated based on the designed load-bearing capacity, and reinforcing cages are added to increase its load-bearing capacity.
3. According to claim 1, a method for producing a prefabricated angle steel grid permanent formwork concrete column: before pouring the internal ordinary concrete, the inner wall of the prefabricated permanent formwork should be cleaned and roughened to facilitate better connection.
4. A connection method for a prefabricated angle steel grid permanent formwork concrete column: step 1: connect the completed lower column, made using the method as described in claim 1, to prefabricated steel structural connectors via reserved angle steels and bolt holes using high-strength bolts; step 2: connect the UHPC permanent formwork of the internal angle steel grid composite structure, where ordinary concrete has not been poured, to prefabricated steel structural connectors via reserved angle steels and bolt holes using high-strength bolts; step 3: completely pour ordinary concrete (11) from the top of the column to fill the upper column and the internal prefabricated steel structural connector, ensuring thorough compaction; step 4: use concrete to smooth the connection points of the steel components between the upper and lower columns' vertical and lateral surfaces, forming a solid connection; step 5: cure the internal ordinary concrete.
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| LU506025A LU506025B1 (en) | 2024-01-04 | 2024-01-04 | A novel method for producing permanent concrete columns using prefabricated angle steel grid formwork |
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| LU506025A LU506025B1 (en) | 2024-01-04 | 2024-01-04 | A novel method for producing permanent concrete columns using prefabricated angle steel grid formwork |
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