Steel reinforced concrete composite structure and construction method thereof

Abstract

The application discloses a steel structure concrete composite structure and a construction method thereof. The construction method is that concrete mixed with shape memory alloy fiber aggregate is poured into a cavity of a steel structure to form the steel structure concrete composite structure. The application can improve the crack resistance and shrinkage resistance of the concrete structure, avoid crack generation and internal cavity hollow caused by concrete shrinkage, and thus improve the forming quality of the steel structure concrete composite structure and the overall bearing capacity and durability of the steel structure concrete composite structure.

Description

Technical Field

[0001] This invention relates to the field of building engineering technology, and in particular to a steel-concrete composite structure and its construction method. Background Technology

[0002] In super high-rise core tube structures, outrigger trusses are installed between the outer frame columns and the core tube. Their primary purpose is to reduce lateral displacement. The mechanism involves increasing the axial force of the outer frame columns under horizontal loads, thereby increasing the overturning moment borne by the frame and simultaneously reducing the overturning moment of the inner core tube. The resulting inflection bending effectively increases the lateral stiffness of the structure, reduces lateral movement, and generally also reduces the shear force sharing ratio of the outer frame. For frame-core tube structures, the reduction in lateral displacement after installing outrigger trusses is significant, while for tube-in-tube structures, the effect is minimal. To ensure bending and compressive strength, the common structural form of outrigger trusses is a steel structure combined with a conventionally poured concrete-steel structure. The disadvantages are that due to the limited internal space of the steel structure, the quality of the internal concrete pouring is difficult to control, easily leading to cavities and other issues, making it difficult to guarantee overall construction quality. Furthermore, during concrete construction, the concrete is prone to temperature cracks and shrinkage cracks due to the heat of hydration and volume reduction during hardening. When cracks develop in the concrete within the steel structure cavity, its load-bearing capacity decreases significantly, affecting its compressive strength. Common methods to address the issues of cavities and cracks include adjusting the concrete mix design, using high-flow-rate fine-aggregate self-compacting concrete or self-compacting micro-expansion fine-aggregate concrete. However, these methods have stringent requirements for mix design and are susceptible to construction factors such as site conditions, making it difficult to guarantee the quality of the concrete molding. Furthermore, steel-concrete composite structures composed of steel-concrete composite columns also exhibit the aforementioned problems. Summary of the Invention

[0003] The purpose of this invention is to provide a steel-concrete composite structure and its construction method to solve the problems of quality issues such as cavities and cracks that easily occur in the concrete poured in traditional steel-concrete composite structures, as well as the difficulty in ensuring the molding quality of the concrete.

[0004] To address the aforementioned technical problems, the present invention provides a steel-concrete composite structure, comprising a steel structure with a hollow cavity, and concrete incorporating shape memory alloy fiber aggregate poured into the cavity of the steel structure.

[0005] To address the aforementioned technical problems, this invention also provides a construction method for a steel-concrete composite structure, in which concrete incorporating shape memory alloy fiber aggregate is poured into the cavity of a steel structure to form a steel-concrete composite structure.

[0006] Furthermore, the construction method for steel-concrete composite structures provided by the present invention further includes: a method for preparing concrete incorporating shape memory alloy fiber aggregate, wherein the method for preparing concrete incorporating shape memory alloy fiber aggregate includes incorporating shape memory alloy fiber aggregate into concrete mix, so that it is uniformly mixed in the concrete to form concrete incorporating shape memory alloy fiber aggregate.

[0007] Furthermore, the construction method of the steel-concrete composite structure provided by the present invention further includes: embedding a temperature sensor in the concrete containing shape memory alloy fiber aggregate within the steel-concrete composite structure, and extending the temperature sensor outside the steel-concrete composite structure via a wire and connecting it to a temperature measuring instrument.

[0008] Furthermore, in the construction method of the steel-concrete composite structure provided by the present invention, the shape memory alloy is a nickel-titanium-copper shape memory alloy.

[0009] Furthermore, the construction method for the steel-concrete composite structure provided by the present invention refers to the steel-concrete composite structure as a cantilever truss or a steel-concrete composite column.

[0010] To address the aforementioned technical problems, the present invention also provides a construction method for a steel-concrete composite structure, comprising:

[0011] A building model is established for the steel-concrete composite structure to be constructed, and the temperature and stress distribution within it is analyzed through the building model.

[0012] The size of the shape memory alloy fiber aggregate is determined based on the temperature distribution. The shape memory alloy fiber aggregate of the determined size is then incorporated into the concrete mix to form concrete with shape memory alloy fiber aggregate. The highest heat of hydration temperature of the concrete with shape memory alloy fiber aggregate must reach the prestressed reverse phase transformation temperature requirement of the shape memory alloy fiber aggregate.

[0013] Temperature measurement points are determined within the steel-concrete composite structure to be constructed based on stress and temperature distribution.

[0014] Concrete incorporating shape memory alloy fiber aggregate is poured into the cavity of a steel structure to form a steel-concrete composite structure. During pouring, it is necessary to ensure that the prestressed reverse phase transformation temperature of the shape memory alloy fiber aggregate is higher than the ambient temperature. Temperature sensors are pre-embedded at the temperature measurement points in the concrete incorporating shape memory alloy fiber aggregate. The temperature sensors are extended outside the steel-concrete composite structure via wires and connected to a temperature measuring instrument.

[0015] Furthermore, the construction method for the steel-concrete composite structure provided by the present invention involves pouring concrete incorporating shape memory alloy fiber aggregate into the cavity of the steel structure to form the steel-concrete composite structure before pouring the concrete incorporating shape memory alloy fiber aggregate into the cavity of the steel structure to form the steel-concrete composite structure. This is done by pouring the concrete incorporating shape memory alloy fiber aggregate into a civil engineering experimental model to determine whether the concrete incorporating shape memory alloy fiber aggregate can be compacted and whether the temperature reaches the prestressed reverse phase transformation temperature value of the shape memory alloy fiber aggregate. If at least one of the compaction and temperature fails to meet the standard, the size of the concrete incorporating shape memory alloy fiber aggregate and / or the mix proportion of the concrete are adjusted, and the civil engineering experimental model is tested again.

[0016] Furthermore, the construction method for the steel-concrete composite structure provided by the present invention also includes a concrete curing method. The concrete curing method includes real-time monitoring of the internal temperature of the concrete within the steel-concrete composite structure using a temperature measuring instrument and its connected temperature sensor. When the hydration heat temperature of the concrete rises slowly and cannot reach the inverse phase transition temperature of the shape memory alloy fiber aggregate, the steel-concrete composite structure is insulated or heated before the peak value of the hydration heat temperature of the concrete to ensure that the hydration heat temperature of the concrete reaches the inverse phase transition temperature of the shape memory alloy fiber aggregate.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0018] The steel-concrete composite structure and its construction method provided by this invention involve pouring concrete incorporating shape memory alloy fiber aggregate into the cavity of the steel structure. The heat of hydration of the concrete excites the shape memory alloy fiber aggregate to generate prestress, which resists stress changes caused by factors such as temperature and shrinkage during the concrete forming process. This balances the internal stress of the concrete structure, improves the crack resistance and shrinkage resistance of the concrete structure, avoids crack formation and internal cavity hollowing caused by concrete shrinkage, thereby improving the forming quality of the steel-concrete composite structure and its overall load-bearing capacity and durability. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the elevation structure of the outrigger truss node;

[0020] Figure 2 This is a schematic diagram of the temperature sensor distribution and the connected temperature measuring instruments within the outrigger frame.

[0021] As shown in the figure:

[0022] 1. Stiffened column, 2. Stiffened beam, 3. Connecting frame, 31. Grouting hole, 4. Outrigger truss, 41. Steel structure, 42. Concrete with shape memory alloy fiber aggregate, 5. Wire, 6. Temperature measuring instrument, 7. Temperature sensor. Detailed Implementation

[0023] The present invention will now be described in detail with reference to the accompanying drawings. The advantages and features of the present invention will become clearer from the following description. It should be noted that the drawings are all in a very simplified form and use non-precise proportions, and are only used to facilitate and clarify the illustration of the embodiments of the present invention.

[0024] Please refer to Figures 1 to 2 This invention provides a steel-concrete composite structure 4, comprising a steel structure 41 with a hollow cavity, and concrete 42 incorporating shape memory alloy fiber aggregate poured into the cavity of the steel structure 41. The steel-concrete composite structure 4 illustrated in the figure is a cantilever truss, but it could also be other steel-concrete composite structures 4 such as steel-concrete composite columns. The joint structure of the cantilever truss includes stiffening columns 1, stiffening beams 2, connecting frames 3, and the cantilever truss itself.

[0025] Please refer to Figures 1 to 2 The present invention also provides a construction method for a steel-concrete composite structure 4, wherein concrete 42 containing shape memory alloy fiber aggregate is poured into the cavity of steel structure 41 to form a steel-concrete composite structure 4.

[0026] To obtain concrete 42 incorporating shape memory alloy fiber aggregate, the construction method of the steel-concrete composite structure 4 provided in this embodiment of the invention further includes: a method for preparing concrete 42 incorporating shape memory alloy fiber aggregate, wherein the method for preparing concrete 42 incorporating shape memory alloy fiber aggregate includes incorporating shape memory alloy fiber aggregate into concrete mix, so that it is uniformly mixed in the concrete to form concrete 42 incorporating shape memory alloy fiber aggregate.

[0027] Please refer to Figures 1 to 2 To monitor the temperature of the concrete within the steel-concrete composite structure 4, the construction method for the steel-concrete composite structure 4 provided in this embodiment of the invention further includes: pre-embedding a temperature sensor 7 within the concrete 42 containing shape memory alloy fiber aggregate within the steel-concrete composite structure 4; extending the temperature sensor 7 outside the steel-concrete composite structure 4 via a wire and connecting it to a temperature measuring instrument 6. The temperature measuring instrument 6 includes at least a microprocessor and a display.

[0028] To improve stress strength, the construction method of the steel-concrete composite structure 4 provided in this embodiment of the invention uses a nickel-titanium-copper shape memory alloy. Specifically, it can be made of Ti-45Ni-5Cu (atomic fraction, %) shape memory alloy, and the annealing temperature is controlled at 350-550℃.

[0029] This invention also provides a construction method for a steel-concrete composite structure 4, comprising:

[0030] Step 101: Establish a building model of the steel-concrete composite structure 4 to be constructed, and analyze the temperature and stress distribution within it through the building model.

[0031] Step 102: Determine the size of the shape memory alloy fiber aggregate based on the temperature distribution, and incorporate the determined shape memory alloy fiber aggregate into the concrete mix to form concrete 42 containing shape memory alloy fiber aggregate; the highest heat of hydration temperature of the concrete 42 containing shape memory alloy fiber aggregate must reach the prestressed reverse phase transformation temperature requirement of the shape memory alloy fiber aggregate. The mass mix proportion of each cubic meter of concrete 42 containing shape memory alloy fiber aggregate can be shown in Table 1 below:

[0032] water cement fly ash Shape memory alloy fiber aggregate fine aggregate coarse aggregate Water reducing agent 151 480 120 7.488 573 1069 13.9

[0033] Table 1

[0034] The coarse aggregate can be crushed stone, and the fine aggregate is sand, with units in kg. The design strength grade of concrete 42 with this mix proportion is C70, the concrete shrinkage stress is 0.468MPa~0.436MPa, the reverse phase transformation stress of the shape memory alloy is about 150MPa, the reverse phase transformation stress of the shape memory alloy fiber aggregate needs to offset the concrete shrinkage stress, and the dosage is calculated based on the concrete shrinkage stress to be 7.488kg~6.976kg. The length of the shape memory alloy fiber aggregate is 20~30mm, and the diameter is 0.2-0.3mm.

[0035] Step 103: Determine the temperature measurement points within the steel-concrete composite structure 4 to be constructed based on the stress and temperature distribution.

[0036] Step 105: Concrete 42 incorporating shape memory alloy fiber aggregate is poured into the cavity of steel structure 41 to form a steel-concrete composite structure 4. During pouring, the prestressing inverse phase transition temperature of the shape memory alloy fiber aggregate must be higher than the ambient temperature. Temperature sensors 7 are pre-embedded at temperature measurement points within the concrete 42 containing the shape memory alloy fiber aggregate. The temperature sensors 7 are extended beyond the steel-concrete composite structure 4 via wires 5 and connected to a temperature measuring instrument 6. Ensuring the prestressing inverse phase transition temperature of the shape memory alloy fiber aggregate is higher than the ambient temperature during pouring ensures that the shape memory alloy fiber aggregate generates prestress in response to temperature changes. The temperature sensor 7 can be connected to the wires 5 using low-temperature soldering to prevent premature inverse phase transition of the shape memory alloy fiber aggregate's prestress. To prevent premature inverse phase transition of the shape memory alloy fiber aggregate's prestress, the temperature during construction must be strictly controlled. If necessary, the concrete should be cooled before pouring to reduce its temperature inside the steel structure 41. For the casting of steel structure 41, grouting holes 31 can be opened on the connecting frame 3 on its upper part, and grouting pipes can be extended into steel structure 41 through grouting holes 31.

[0037] To ensure the quality of the pouring, the construction method for the steel-concrete composite structure 4 provided in this embodiment of the invention may further include:

[0038] Step 104: Before pouring the concrete 42 containing shape memory alloy fiber aggregate into the cavity of the steel structure 41 to form the steel-concrete composite structure 4, the concrete 42 containing shape memory alloy fiber aggregate is poured through a civil engineering experimental model to determine whether the concrete containing shape memory alloy fiber aggregate can be poured densely and whether the temperature reaches the prestressed reverse phase transformation temperature value of the shape memory alloy fiber aggregate. If at least one of the dense pouring and temperature fails to meet the requirements, the size of the concrete containing shape memory alloy fiber aggregate and / or the concrete mix ratio are adjusted, and the civil engineering experimental model is tested again. Adjusting the concrete mix ratio can also ensure that the shape memory alloy fiber aggregate can be uniformly mixed and distributed in the concrete, ensuring the overall fluidity.

[0039] To improve the curing effect of the steel-concrete composite structure 4, the construction method of the steel-concrete composite structure 4 provided in this embodiment of the invention may further include:

[0040] Step 106, concrete curing method, the concrete curing method includes real-time monitoring of the internal temperature of the concrete in the steel-concrete composite structure 4 by using a temperature measuring instrument 6 and its connected temperature sensor 7. When the hydration heat temperature of the concrete rises slowly and cannot reach the reverse phase transformation temperature of the shape memory alloy fiber aggregate, the steel-concrete composite structure 4 is insulated or heated before the peak value of the hydration heat temperature of the concrete to ensure that the hydration heat temperature of the concrete reaches the reverse phase transformation temperature of the shape memory alloy fiber aggregate.

[0041] The steel-concrete composite structure 4 and its construction method provided in this embodiment of the invention involve pouring concrete 42 containing shape memory alloy fiber aggregate into the cavity of the steel structure 41. The heat of hydration of the concrete excites the shape memory alloy fiber aggregate to generate prestress, which resists stress changes caused by factors such as temperature and shrinkage during the concrete forming process, balances the internal stress of the concrete structure, improves the crack resistance and shrinkage resistance of the concrete structure, avoids crack formation and internal cavity hollowing caused by concrete shrinkage, thereby improving the forming quality of the steel-concrete composite structure 4 and its overall load-bearing capacity and durability.

[0042] The steel-concrete composite structure 4 and its construction method provided in this embodiment of the invention can ensure the offsetting of internal stress in concrete by controlling the construction operation temperature and concrete curing temperature; it has the advantages of convenient operation, simple procedures, and easy control of construction quality.

[0043] The steel-concrete composite structure 4 and its construction method provided in this embodiment of the invention feature a tight connection between the concrete 42, which incorporates shape memory alloy fiber aggregate, and the steel structure 41, reducing the exposed area and improving the corrosion resistance of the steel structure 41. This also enhances the fire resistance of the steel-concrete composite structure 4. At higher temperatures, the internal concrete generates prestress, improving the overall bending and load-bearing capacity of the structure and preventing collapse.

[0044] This invention is not limited to the specific embodiments described above. Obviously, the embodiments described above are only a part of the embodiments of this invention, not all of them. All other embodiments obtained by those skilled in the art based on the described embodiments of this invention are within the scope of protection of this invention. Those skilled in the art can make other modifications and variations to this invention. Therefore, if these modifications and variations of this invention fall within the scope of the claims of this invention, then this invention also intends to include these modifications and variations.

Claims

1. A construction method for a steel-concrete composite structure, characterized in that, include: A building model is established for the steel-concrete composite structure to be constructed, and the temperature and stress distribution within it is analyzed through the building model. The size of the shape memory alloy fiber aggregate is determined based on the temperature distribution. The shape memory alloy fiber aggregate of the determined size is then incorporated into the concrete mix to form concrete with shape memory alloy fiber aggregate. The highest heat of hydration temperature of the concrete with shape memory alloy fiber aggregate must reach the prestressed reverse phase transformation temperature requirement of the shape memory alloy fiber aggregate. Temperature measurement points are determined within the steel-concrete composite structure to be constructed based on stress and temperature distribution. Concrete incorporating shape memory alloy fiber aggregate is poured into the cavity of the steel structure to form the steel-concrete composite structure. During pouring, it is necessary to ensure that the prestressed reverse phase transition temperature of the shape memory alloy fiber aggregate is higher than the ambient temperature. Temperature sensors are pre-embedded at the temperature measurement points within the concrete incorporating shape memory alloy fiber aggregate. The temperature sensors are extended beyond the steel-concrete composite structure via wires and connected to a temperature measuring instrument.

2. The construction method for the steel-concrete composite structure according to claim 1, characterized in that, Before pouring concrete incorporating shape memory alloy fiber aggregate into the cavity of a steel structure to form a steel-concrete composite structure, a civil engineering experimental model is used to pour the concrete incorporating shape memory alloy fiber aggregate to determine whether the concrete can be densely poured and whether the temperature reaches the prestressed reverse phase transformation temperature value of the shape memory alloy fiber aggregate. If at least one of the dense pouring and temperature fails to meet the requirements, the size of the concrete incorporating shape memory alloy fiber aggregate and / or the mix proportion of the concrete are adjusted, and the civil engineering experimental model is tested again.

3. The construction method for the steel-concrete composite structure according to claim 1, characterized in that, It also includes a method for concrete curing, which involves real-time monitoring of the internal temperature of the concrete in the steel-concrete composite structure using a temperature measuring instrument and its connected temperature sensor. When the hydration heat temperature of the concrete rises slowly and cannot reach the inverse phase transition temperature of the shape memory alloy fiber aggregate, the steel-concrete composite structure is insulated or heated before the peak value of the hydration heat temperature of the concrete to ensure that the hydration heat temperature of the concrete reaches the inverse phase transition temperature of the shape memory alloy fiber aggregate.

4. The construction method for the steel-concrete composite structure according to claim 1, characterized in that, The shape memory alloy is a nickel-titanium-copper shape memory alloy.

5. The construction method for the steel-concrete composite structure according to claim 1, characterized in that, The steel-concrete composite structure is a cantilever truss or a steel-concrete composite column.

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