Design method and device for reducing use amount of lower chord steel bars of laminated slab and terminal

Abstract

The invention discloses a design method and device for reducing the using amount of lower chord steel bars of a laminated slab and a terminal, and the method comprises the steps that a target balance equation is constructed, and the target balance equation is an axial force balance equation of a plane truss prefabricated bottom plate component in the laminated slab in the construction stage; obtaining a target relational expression based on the target balance equation, wherein the target relational expression represents a cross section size relationship between an upper chord steel bar and a lower chord steel bar of the steel bar truss; and designing the lower chord steel bar diameter of the target steel bar truss based on the target relational expression. According to the method, the cross section size relationship between the lower chord steel bars and the upper chord steel bars of the target steel bar truss is inferred reversely by constructing the target balance equation, so that the dosage ratio of the upper chord steel bars and the lower chord steel bars is more reasonable, the design dosage of the lower chord steel bars of the steel bar truss is effectively reduced, and the production cost of the laminated slab is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of construction engineering, and in particular to a design method, a device and a terminal for reducing the amount of steel bars used in the lower chord of a composite slab. Background Art

[0002] While concrete composite slabs and steel truss decking are widely used in traditional prefabricated floor slab technology systems, structural flaws and process bottlenecks have severely hampered the industrialization of construction. Specifically, traditional concrete composite slabs suffer from performance shortcomings in multiple dimensions, including spatial utilization and mechanical performance. The precast layer thickness is fixed at 60mm, while the cast-in-place layer thickness typically fluctuates between 70 and 80mm. Structural designs with a total thickness of 130mm or greater add an additional 30mm of redundant thickness compared to conventional cast-in-place slabs. This not only compresses building space but also forces higher standards for foundation and load-bearing component design, leading to a surge in both material and construction costs.

[0003] In view of this, within existing technologies, a breakthrough was made in the traditional reinforcement paradigm for composite slabs. Through innovative lower chord reinforcement optimization algorithms and spatial topology reconstruction technology, the dual goals of reducing steel usage by 20% to 30% and reducing the temporary support system by 50% were achieved, while ensuring structural safety and redundancy. By reducing the thickness of the precast base slab from 60mm to 30mm, a 50% reduction in thickness, optimizing material usage reduced the component's deadweight by 18%, and relying on a flat truss structure to replace the traditional triangular truss, component transportation efficiency increased by 40%. The result was a "composite carbon fiber reinforced thin concrete flat steel truss composite slab" component. The reinforcement laying method is fully compatible with cast-in-place slabs, truly achieving equivalent mechanical performance between prefabricated floor slabs and cast-in-place structures.

[0004] Conventionally, the diameters of the upper and lower chord steel bars of a composite slab are usually designed to be the same. However, load tests have shown that the failure mode of composite carbon fiber reinforced thin concrete flat steel truss composite slabs is manifested as buckling failure of the upper chord steel bars, while no obvious cracks appear in the bottom slab. Therefore, a new dosage design method is needed to make the dosage ratio of the upper and lower chord steel bars more reasonable.

[0005] Therefore, the existing technology needs to be improved and enhanced. Summary of the Invention

[0006] In view of the above-mentioned defects of the prior art, the present invention provides a design method, device and terminal for reducing the amount of steel bars used in the lower chord of the composite slab, aiming to solve the problem of unreasonable ratio of upper and lower steel bars used in the composite carbon fiber reinforced thin concrete flat steel truss composite slab in the prior art.

[0007] In order to solve the above technical problems, the technical solutions adopted by the present invention are as follows:

[0008] A first aspect of the present invention provides a design method, device, and terminal for reducing the amount of steel bars used in the lower chord of a composite slab. The method comprises:

[0009] Constructing a target equilibrium equation, wherein the target equilibrium equation is an axial force equilibrium equation of a plane truss prefabricated bottom plate component in the composite slab during the construction phase;

[0010] Obtaining a target relationship based on the target equilibrium equation, wherein the target relationship represents a cross-sectional size relationship between an upper chord steel bar and a lower chord steel bar of the steel truss;

[0011] The diameter of the bottom chord steel bars of the target steel truss is designed based on the target relationship.

[0012] In one implementation, constructing the target balance equation includes:

[0013] A target reduction coefficient is designed, and the target equilibrium equation is obtained based on the target reduction coefficient so that the internal axial force in the cross section of the plane truss precast plate component is balanced. The target reduction coefficient is the reduction coefficient of the tensile stress of the precast bottom plate concrete relative to the design value of the concrete tensile strength.

[0014] In one implementation, the target balance equation is:

[0015] N=A' s σ′ s -A s σ s -cbkf t =0;

[0016] Where N is the design value of the axial force of the plane truss precast plate component, a′ s 、A s are the cross-sectional areas of the upper and lower chord steel bars of the steel truss, σ′ s , σ s are the design values ​​of the stress of the upper and lower chord steel bars of the steel truss, c is the thickness of the precast base plate, b is the spacing between steel trusses, corresponding to the effective precast base plate width of a single steel truss, k is the target reduction factor, f t is the design value of tensile strength of precast base slab concrete.

[0017] In one implementation, the design target reduction factor includes:

[0018] A composite plate geometric model is constructed, and a finite element parametric analysis is performed on the composite plate under different parameters based on the composite plate geometric model and the target equilibrium equation to obtain a solution formula for the target reduction coefficient that satisfies the target equilibrium equation.

[0019] In one implementation, the target reduction coefficient is calculated as follows:

[0020] k=1.927-0.00284h-0.0305d1-0.07d2;

[0021] Where h is the thickness of the composite slab, d1 and d2 are the diameters of the upper and lower chord steel bars of the steel truss, respectively.

[0022] In one implementation, the target relationship is:

[0023]

[0024] Among them, A′ s 、A s are the cross-sectional areas of the upper and lower chord steel bars of the steel truss, σ' s , σ s are the design values ​​of the stress of the upper and lower chord steel bars of the steel truss, c is the thickness of the precast base plate, b is the spacing between steel trusses, corresponding to the effective precast base plate width of a single steel truss, k is the target reduction factor, f t is the design value of tensile strength of precast base slab concrete, f y is the design value of steel bar tensile strength.

[0025] In one implementation, designing the diameter of the bottom chord steel bar of the target steel bar truss based on the target relationship includes:

[0026] Obtaining a design stress value of the upper chord steel bars of the target steel truss, and calculating a cross-sectional area of ​​the upper chord steel bars of the target steel truss based on the design stress value and the design compressive strength value of the steel bars;

[0027] Obtaining a design stress value of the bottom chord steel bars of the target steel truss, and calculating a cross-sectional area of ​​the bottom chord steel bars of the target steel truss based on the design stress values ​​of the top and bottom chord steel bars of the target steel truss, a design value of the tensile strength of the steel bars, a cross-sectional area of ​​the top chord steel bars of the target steel truss, and the target reduction factor;

[0028] The diameter of the bottom chord steel bar of the target steel bar truss is obtained based on the cross-sectional area of ​​the bottom chord steel bar of the target steel bar truss.

[0029] A second aspect of the present invention provides a design device for reducing the amount of reinforcement used in the lower chord of a composite slab, comprising:

[0030] An equation construction module is used to construct a target equilibrium equation, wherein the target equilibrium equation is an axial force equilibrium equation of a plane truss prefabricated bottom plate component in a composite plate during the construction phase;

[0031] a relationship analysis module, configured to obtain a target relationship expression based on the target equilibrium equation, wherein the target relationship expression represents a relationship between the cross-sectional sizes of the upper chord steel bars and the lower chord steel bars of the steel truss;

[0032] The usage design module is used to design the diameter of the lower chord steel bars of the target steel bar truss based on the target relationship.

[0033] A third aspect of the present invention provides a terminal comprising a processor and a computer-readable storage medium communicatively connected to the processor, wherein the computer-readable storage medium is suitable for storing a plurality of instructions, and the processor is suitable for calling the instructions in the computer-readable storage medium to execute the steps of the design method for reducing the amount of steel bars used in the lower chord of a composite slab as described above.

[0034] A fourth aspect of the present invention provides a computer-readable storage medium storing one or more programs, which can be executed by one or more processors to implement the steps of the design method for reducing the amount of steel bars used in the lower chord of a composite slab as described in any of the above items.

[0035] Compared with the prior art, the present invention provides a design method, device, and terminal for reducing the amount of lower chord steel bars used in composite slabs. The design method for reducing the amount of lower chord steel bars used in composite slabs constructs a target equilibrium equation, which is the axial force equilibrium equation of the prefabricated bottom plate component of the plane truss in the composite slab during the construction phase. Then, based on the target equilibrium equation, a target relationship is obtained, which represents the cross-sectional size relationship between the upper and lower chord steel bars of the steel truss. Finally, the diameter of the lower chord steel bar of the target steel truss is designed based on the target relationship. The design method for reducing the amount of lower chord steel bars used in composite slabs proposed by the present invention reversely infers the cross-sectional size relationship between the lower and upper chord steel bars of the target steel truss by constructing a target equilibrium equation, thereby making the usage ratio of the upper and lower chord steel bars more reasonable, effectively reducing the design amount of the lower chord steel bars of the steel truss, and reducing the production cost of the composite slab. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 A flow chart of an embodiment of a design method for reducing the amount of reinforcement used in the lower chord of a composite slab provided by the present invention;

[0037] Figure 2 A cross-sectional view of a planar truss prefabricated bottom plate component of a composite slab according to an embodiment of the design method for reducing the amount of reinforcement used in the lower chord of a composite slab provided by the present invention;

[0038] Figure 3 A structural principle diagram of an embodiment of a design device for reducing the amount of reinforcement used in the lower chord of a composite slab provided by the present invention;

[0039] Figure 4 A schematic diagram of the principles of an embodiment of a terminal provided by the present invention. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical solution and effect of the present invention clearer and more specific, the present invention is further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0041] It will be understood by those skilled in the art that, unless expressly stated otherwise, the singular forms "a", "an", "said" and "the" used herein may also include the plural forms. It should be further understood that the term "comprising" used in the description of the present invention refers to the presence of the features, integers, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof. It should be understood that when we refer to an element as being "connected" or "coupled" to another element, it may be directly connected or coupled to the other element, or there may be intermediate elements. In addition, "connected" or "coupled" as used herein may include wireless connections or wireless couplings. The term "and / or" used herein includes all or any units and all combinations of one or more associated listed items.

[0042] It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by those skilled in the art in the art to which the present invention belongs. It should also be understood that terms such as those defined in common dictionaries should be understood to have meanings consistent with their meanings in the context of the prior art and will not be interpreted in an idealized or overly formal sense unless specifically defined as herein.

[0043] The design method for reducing the amount of steel bars used in the lower chord of a composite plate provided by the present invention can be applied to a terminal with computing capabilities. The terminal can execute the design method for reducing the amount of steel bars used in the lower chord of a composite plate provided by the present invention to design the diameter of the steel bars in the lower chord of a composite plate.

[0044] Example 1

[0045] This embodiment provides a design method for reducing the amount of reinforcement used in the lower chord of a composite slab. This method uses equilibrium equations to design the diameters of the upper and lower chords of a target steel truss, enabling the use of smaller diameter lower chords in practice. This effectively reduces the amount of reinforcement used in the lower chord of the composite slab, further reducing the production cost of concrete flat steel truss composite slabs.

[0046] Specifically, if Figure 1As shown, in one embodiment of the design method for reducing the amount of steel bars used in the lower chord of a composite slab provided by the present invention, the design method for reducing the amount of steel bars used in the lower chord of a composite slab includes the following steps:

[0047] S100: Construct a target equilibrium equation, and obtain a target stress calculation formula based on the target equilibrium equation.

[0048] Specifically, against the backdrop of traditional prefabricated floor slabs facing multiple challenges, including high costs, low efficiency, and quality issues, Mr. Shan Chengmin's team has innovatively developed a thin, flat truss prefabricated slab technology system. Through structural reconstruction and material upgrades, this system has achieved a breakthrough improvement in the performance of prefabricated floors. This system, with its core design concept of "thinning, strengthening, and synergy," systematically addresses the technical pain points of traditional composite slabs and reinforced truss floor decks.

[0049] To address the space loss and increased costs caused by the redundant thickness of the precast layers of traditional composite slabs, the R&D team reduced the thickness of the precast baseplate from 60mm to 30mm, a 50% reduction. This revolutionary design not only reduces the component's deadweight by 18% through optimized material usage, but also relies on a flat truss structure to replace the traditional triangular truss, increasing component transportation efficiency by 40%. Regarding material innovation, a fine stone concrete casting process is employed, incorporating a 30mm x 30mm pore size carbon fiber / basalt composite mesh. This composite reinforcement system increases the precast baseplate's crack resistance by three times, its bending bearing capacity by 25%, and its ductility by 1.8 times that of traditional components, effectively addressing the technical challenge of thin components being prone to cracking.

[0050] Reference Figure 2 , Figure 2This is a cross-sectional view of the flat truss precast base plate component of this new composite slab. As can be seen, in terms of structural connection and construction process optimization, the flat truss thin precast slab achieves a qualitative leap in construction efficiency through three key technological innovations: First, the bottom reinforcement is embedded in the precast base plate and provided with a 15mm adjustable protective layer. The web reinforcement extends to form a 40-50mm skived structure. Combined with a mechanical interlocking system formed by cold-drawn steel wire with a diameter of ≥4.5mm, this improves the component's anti-slip capacity during hoisting by 60%, and maintains positioning accuracy within ±2mm. Second, the close-fitting installation process eliminates inter-slab joints. The precast slab's four-sided design reduces formwork usage by 70% and shortens the construction period by 3-5 days per thousand square meters. Third, the cast-in-place layer reinforcement is laid perpendicular to the truss reinforcement without protective layer blocks. This direct laying method improves rebar binding efficiency by 50%. The cast-in-place layer thickness can be flexibly adjusted within a range of 70-120mm according to project requirements, achieving dual optimization of structural performance and economic efficiency. The final product of this technical system is the "composite carbon fiber reinforced thin concrete flat steel truss composite slab" component, whose steel bar laying method is fully compatible with cast-in-place slabs. Its bidirectional force transmission performance has been verified by full-scale tests, truly realizing the equivalent substitution of prefabricated floor slabs and cast-in-place structures in mechanical properties.

[0051] In this embodiment, the composite slab is a general term for a floor slab entity formed by a thin prefabricated base plate, a cast-in-place concrete layer, and additional steel bars after the cast-in-place concrete layer solidifies; the thin prefabricated base plate is a general term for a flat steel bar truss and a prefabricated concrete thin base plate, etc., which is produced in a factory and transported to the construction site for installation. It is an important component of the composite slab and is the main component that bears the load during the construction phase.

[0052] For this new type of composite slab, the current conventional practice is to design the diameters of the upper and lower chord steel bars to be the same size. The original upper and lower chord steel bar design formulas are:

[0053]

[0054] Among them, σ′ s , σ s are the design values ​​of the stress of the upper and lower chord steel bars of the reinforced truss, A′ s 、A s are the cross-sectional areas of the upper and lower chord steel bars of the reinforced truss, M is the design value of the bending moment of the plane truss precast plate component, h is the thickness of the composite plate, and a′ s 、a s are the distances from the center of the upper and lower chord steel bars of the steel truss to the upper and lower edges of the composite slab, respectively, and f′ y is the design value of steel bar compressive strength, f yis the design value of the tensile strength of the steel bars. It can be seen that the diameters of the top and bottom chords of the steel trusses designed using this formula are the same. However, tests have shown that the stresses on the top and bottom chords of the steel trusses are different.

[0055] Specifically, in this embodiment, a component test was carried out. The top and bottom rib diameters of the test specimens involved were both 10 mm, the plate length was 3600 mm, and the two ends of the specimens were simply supported. By testing three specimens, their minimum ultimate load was measured to be 6.85 kN / m 2 , this load value reached 1.7 times the standard value of the construction load. From the failure morphology, the specimen showed the buckling failure characteristics of the upper chord steel bars. When the failure occurred, the corresponding deflection was 1 / 88. It is worth noting that during the entire test process, no cracks visible to the naked eye appeared at the bottom of the precast slab. This phenomenon fully demonstrates that the composite carbon fiber mesh plays a significant role in improving the ductile deformation capacity and crack resistance of concrete. At the same time, it also shows that the stress on the upper chord steel bars of the steel truss will be greater than the stress on the lower chord steel bars. The amount of the lower chord steel bars can be appropriately reduced without affecting the overall use effect, so as to save the manufacturing cost of the composite slab.

[0056] Based on this, this embodiment proposes a design method for reducing the amount of lower chord steel bars used in composite slabs. By constructing a target equilibrium equation and then obtaining a target stress calculation formula based on the target equilibrium equation, the relationship between the diameter of the lower chord steel bars and the diameter of the upper chord steel bars that satisfies the target equilibrium equation is obtained.

[0057] Specifically, in this embodiment, the target equilibrium equation is the axial force equilibrium equation for the planar truss precast plate component. In constructing this target equilibrium equation, a plastic design approach is employed, assuming that the entire cross-section of the precast concrete base plate is uniformly stressed and that its tensile stress is k times the design tensile strength value, where, in this embodiment, k is a target reduction factor. Specifically, the target equilibrium equation is obtained by designing the target reduction factor so that the internal axial forces within the cross-section of the planar truss precast plate component are balanced, i.e., the net force of each component is zero. The target reduction factor represents the reduction factor of the tensile stress of the precast base plate concrete relative to the design tensile strength of the concrete.

[0058] Therefore, in this embodiment, the equilibrium equation can be expressed as:

[0059] N=A′ s σ′ s -A s σ s -cbkf t =0;

[0060]

[0061] That is, the target balance equation is:

[0062] N=A' s σ′ s -A s σ s -cbkf t =0;

[0063] Where N is the design value of the axial force of the plane truss precast plate component, M is the design value of the bending moment of the plane truss precast plate component, and A′ s 、A s are the cross-sectional areas of the upper and lower chord steel bars of the steel truss, σ′ s , σ s are the design values ​​of the stress of the upper and lower chord steel bars of the steel truss, c is the thickness of the precast base plate, b is the spacing between steel trusses, corresponding to the effective precast base plate width of a single steel truss, k is the target reduction factor, f t is the design value of tensile strength of precast base slab concrete.

[0064] In this embodiment, finite element parametric analysis is performed to design the target reduction coefficient by numerical fitting. Specifically, the designed target reduction coefficient includes:

[0065] A composite plate geometric model is constructed, and a finite element parametric analysis is performed on the composite plate under different parameters based on the composite plate geometric model and the target equilibrium equation to obtain a solution formula for the target reduction coefficient that satisfies the target equilibrium equation.

[0066] Specifically, corresponding to different parameters L, h, d1, and d2, L is the calculated length of the composite plate, h is the thickness of the composite plate, and d1 and d2 are the diameters of the upper and lower chord steel bars of the steel truss, respectively.

[0067] The stress design values ​​σ' of the upper and lower chord steel bars of the reinforced truss with different parameters L, h, d1, and d2 are obtained. s and σ s The calculation results are then back-calculated according to the target balance equation to obtain multiple sets of coefficients k, and finally a genetic algorithm is used to establish the functional relationship between k and parameters h, d1, and d2.

[0068] Specifically, in this embodiment, the four parameters involved are first studied: L, h, d1, and d2. Then, finite element analysis software is used to perform multiple calculations corresponding to different parameter combinations (i.e., different L, h, d1, and d2 values).

[0069] Each calculation will produce two sets of stress results: the design value of the stress of the upper and lower chord steel bars of the steel truss σ' s and σ s These stress values ​​are the stress responses of the top and bottom chords of the reinforced trusses in the plane truss precast slab components under specific conditions.

[0070] Back-calculation coefficient k: Based on the target balance equation, many sets of coefficient k are back-calculated.

[0071] The “inverse calculation” here means that, given σ′ s and σ s The value of , and the target equilibrium equation, can be solved for the value of k.

[0072] Then, a functional relationship is established based on the genetic algorithm. Specifically, a functional relationship is established to describe how the coefficient k changes with the changes of the parameters h, d1, and d2.

[0073] Specifically, a genetic algorithm is an optimization algorithm that mimics the principles of natural selection and genetics to find the optimal solution to a problem. In this scenario, the genetic algorithm is used to find a function that best fits the relationship between the values ​​of k and h, d1, and d2 previously obtained through finite element analysis.

[0074] The genetic algorithm continuously adjusts the parameters of the function (such as polynomial coefficients, exponents, etc.) through an iterative process to minimize the error between the predicted k value and the actual k value.

[0075] Finally, through the optimization process of the genetic algorithm, a functional relationship between k and h, d1, and d2 can be obtained.

[0076] This functional relationship can be used to predict the approximate value of k for given values ​​of h, d1, and d2 without having to perform complex finite element analysis again.

[0077] Specifically, according to the results of finite element parametric analysis, the solution formula of the target reduction coefficient obtained by numerical fitting is:

[0078] k=1.927-0.00284h-0.0305d1-0.07d2;

[0079] Where h is the thickness of the composite slab, d1 and d2 are the diameters of the upper and lower chord steel bars of the steel truss, respectively.

[0080] S200: Obtain a target relationship expression based on the target equilibrium equation, where the target relationship expression represents a cross-sectional size relationship between an upper chord steel bar and a lower chord steel bar of a steel truss.

[0081] Specifically, in this embodiment, the amount of upper chord reinforcement of the target reinforced truss is designed by reducing the amount of lower chord reinforcement of the composite slab. Therefore, the design formula of the upper chord reinforcement in the original upper and lower chord reinforcement design formula is maintained to design the amount of upper chord reinforcement. After obtaining the target relationship based on the target equilibrium equation, the amount of lower chord reinforcement of the target reinforced truss is designed based on the target relationship.

[0082] That is, in this embodiment, the design value formulas of the upper and lower chord steel bar stresses of the target steel bar truss are:

[0083]

[0084]

[0085] Where M is the design value of the bending moment of the plane truss precast plate component, a′ s 、a s are the distances from the center of the upper and lower chord steel bars of the steel truss to the upper and lower edges of the composite slab, A′ s 、A s are the cross-sectional areas of the upper and lower chord steel bars of the steel truss, σ′ s , σ s are the design values ​​of the stress of the upper and lower chord steel bars of the steel truss, c is the thickness of the precast base plate, b is the spacing between steel trusses, corresponding to the effective precast base plate width of a single steel truss, k is the target reduction factor, f t is the design value of tensile strength of precast base slab concrete, f′ y is the design value of steel bar compressive strength, f y is the design value of steel bar tensile strength.

[0086] S300: Designing a diameter of the lower chord steel bars of a target steel bar truss based on the target relationship.

[0087] The step of designing the diameter of the bottom chord steel bar of the target steel bar truss based on the target relationship includes:

[0088] Obtaining a design stress value of the upper chord steel bars of the target steel truss, and calculating a cross-sectional area of ​​the upper chord steel bars of the target steel truss based on the design stress value and the design compressive strength value of the steel bars;

[0089] Obtaining a design stress value of the bottom chord steel bars of the target steel truss, and calculating a cross-sectional area of ​​the bottom chord steel bars of the target steel truss based on the design stress values ​​of the top and bottom chord steel bars of the target steel truss, a design value of the tensile strength of the steel bars, a cross-sectional area of ​​the top chord steel bars of the target steel truss, and the target reduction factor;

[0090] The diameter of the bottom chord steel bar of the target steel bar truss is obtained based on the cross-sectional area of ​​the bottom chord steel bar of the target steel bar truss.

[0091] Specifically, That is the target relationship. Based on the stress design value formula of the upper and lower chord steel bars of the target steel truss, and obtaining the stress design values ​​of the upper and lower chord steel bars of the target steel truss, the cross-sectional area of ​​the lower chord steel bars of the target steel truss can be calculated based on the target relationship and the value of k. Based on the cross-sectional area of ​​the lower chord steel bars of the target steel truss, the corresponding amount of the lower chord steel bars required for the final target composite plate can be obtained.

[0092] It can be seen that by adopting the innovative method of reducing the amount of lower chord steel bars of the composite slab provided in this embodiment, the diameter of the lower chord steel bars can be greatly reduced, saving the amount of steel bars, and being safe and reliable. Specifically, according to conventional practice, the diameter of the upper and lower chord steel bars is the same value, as shown in the original upper and lower chord steel bar design formulas. This is determined by the algorithm and must be the same, which makes the stress of the lower chord steel bar very small, which is not economical. By adopting the method in this article, it can be adjusted as needed, as long as the steel bar stress calculated by the target relationship does not exceed the design specification limit. For example, if the upper chord steel bar is 12, the lower chord steel bar can be 10, 8, or even 6 according to calculation. Compared with 12, the steel bar area can be saved by 31%, 55%, and 75%, respectively.

[0093] In summary, this embodiment provides a design method for reducing the amount of lower chord steel bars in a composite slab by constructing a target equilibrium equation, which is the axial force equilibrium equation of the prefabricated bottom plate component of the plane truss in the composite slab during the construction phase. Then, based on the target equilibrium equation, a target relationship is obtained, which represents the cross-sectional size relationship between the upper chord steel bars and the lower chord steel bars of the steel truss. Finally, based on the target relationship, the diameter of the lower chord steel bars of the target steel truss is designed. The design method for reducing the amount of lower chord steel bars in a composite slab proposed in this embodiment reversely infers the cross-sectional size relationship between the lower chord steel bars and the upper chord steel bars of the target steel truss by constructing a target equilibrium equation, thereby making the usage ratio of the upper and lower chord steel bars more reasonable, effectively reducing the design amount of the lower chord steel bars of the steel truss, and reducing the production cost of the composite slab.

[0094] It should be understood that although the steps in the flowcharts provided in the accompanying drawings of the present invention are shown in sequence as indicated by the arrows, these steps are not necessarily performed in the order indicated by the arrows. Unless otherwise specified herein, there is no strict order restriction on the execution of these steps, and these steps can be performed in other orders. Moreover, at least a portion of the steps in the flowcharts may include multiple sub-steps or multiple stages, and these sub-steps or stages are not necessarily performed at the same time, but can be performed at different times. The execution order of these sub-steps or stages is not necessarily sequential, but can be performed in rotation or alternation with other steps or at least a portion of the sub-steps or stages of other steps.

[0095] Those skilled in the art will understand that all or part of the processes in the above-mentioned embodiment methods can be implemented by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided by the present invention may include non-volatile and / or volatile memory. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in many forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), Synchronous Link DRAM (SLDRAM), Rambus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), etc.

[0096] Example 2

[0097] Based on the above embodiments, the present invention also provides a design device for reducing the amount of steel bars used in the lower chord of a composite slab. Figure 3 As shown, the design device for reducing the amount of reinforcement used in the lower chord of the composite slab includes:

[0098] An equation construction module, for constructing a target equilibrium equation, wherein the target equilibrium equation is an axial force equilibrium equation of a plane truss prefabricated bottom plate component in a composite slab during the construction phase, as specifically described in the first embodiment;

[0099] a relationship analysis module, configured to obtain a target relationship expression based on the target equilibrium equation, wherein the target relationship expression represents a cross-sectional relationship between an upper chord steel bar and a lower chord steel bar of a steel truss, as specifically described in the first embodiment;

[0100] The usage design module is used to design the diameter of the lower chord steel bars of the target steel bar truss based on the target relationship, as specifically described in the first embodiment.

[0101] Example 3

[0102] Based on the above embodiments, the present invention also provides a terminal, such as Figure 4 As shown, the terminal includes a processor 10 and a memory 20. Figure 4 Only some of the components of the terminal are shown, but it should be understood that implementation of all of the shown components is not required, and more or fewer components may be implemented instead.

[0103] In some embodiments, the memory 20 may be an internal storage unit of the terminal, such as a hard disk or memory of the terminal. In other embodiments, the memory 20 may also be an external storage device of the terminal, such as a plug-in hard disk, a smart memory card (Smart Media Card, SMC), a secure digital (Secure Digital, SD) card, a flash card (Flash Card), etc. equipped on the terminal. Furthermore, the memory 20 may also include both an internal storage unit of the terminal and an external storage device. The memory 20 is used to store application software and various types of data installed on the terminal. The memory 20 may also be used to temporarily store data that has been output or is to be output. In one embodiment, a design program 30 for reducing the amount of steel bars used in the lower chord of a composite plate is stored on the memory 20, and the design program 30 for reducing the amount of steel bars used in the lower chord of a composite plate can be executed by the processor 10, thereby realizing the design method for reducing the amount of steel bars used in the lower chord of a composite plate in the present application.

[0104] In some embodiments, the processor 10 may be a central processing unit (CPU), a microprocessor, or other chip, configured to execute program codes or process data stored in the memory 20, such as executing the design method for reducing the amount of steel bars used in the lower chord of a composite slab.

[0105] In one embodiment, when the processor 10 executes the design program 30 for reducing the amount of reinforcement used in the lower chord of a composite slab in the memory 20, the following steps are implemented:

[0106] Constructing a target equilibrium equation, wherein the target equilibrium equation is an axial force equilibrium equation of a plane truss prefabricated bottom plate component in the composite slab during the construction phase;

[0107] Obtaining a target relationship based on the target equilibrium equation, wherein the target relationship represents a cross-sectional size relationship between an upper chord steel bar and a lower chord steel bar of the steel truss;

[0108] The diameter of the bottom chord steel bars of the target steel truss is designed based on the target relationship.

[0109] In one implementation, constructing the target balance equation includes:

[0110] A target reduction coefficient is designed, and the target equilibrium equation is obtained based on the target reduction coefficient so that the internal axial force in the cross section of the plane truss precast plate component is balanced. The target reduction coefficient is the reduction coefficient of the tensile stress of the precast bottom plate concrete relative to the design value of the concrete tensile strength.

[0111] In one implementation, the target balance equation is:

[0112] N=A' s σ′ s -A s σ s -cbkf t =0;

[0113] Where N is the design value of the axial force of the plane truss precast plate component, A′ s 、A s are the cross-sectional areas of the upper and lower chord steel bars of the steel truss, σ' s , σ s are the design values ​​of the stress of the upper and lower chord steel bars of the steel truss, c is the thickness of the precast base plate, b is the spacing between steel trusses, corresponding to the effective precast base plate width of a single steel truss, k is the target reduction factor, f t is the design value of tensile strength of precast base slab concrete.

[0114] In one implementation, the design target reduction factor includes:

[0115] A composite plate geometric model is constructed, and a finite element parametric analysis is performed on the composite plate under different parameters based on the composite plate geometric model and the target equilibrium equation to obtain a solution formula for the target reduction coefficient that satisfies the target equilibrium equation.

[0116] In one implementation, the target reduction coefficient is calculated as follows:

[0117] k=1.927-0.00284h-0.0305d1-0.07d2;

[0118] Where h is the thickness of the composite slab, d1 and d2 are the diameters of the upper and lower chord steel bars of the steel truss, respectively.

[0119] In one implementation, the target relationship is:

[0120]

[0121] Among them, A′ s 、A s are the cross-sectional areas of the upper and lower chord steel bars of the steel truss, σ' s , σ s are the design values ​​of the stress of the upper and lower chord steel bars of the steel truss, c is the thickness of the precast base plate, b is the spacing between steel trusses, corresponding to the effective precast base plate width of a single steel truss, k is the target reduction factor, f t is the design value of tensile strength of precast base slab concrete, f y is the design value of steel bar tensile strength.

[0122] In one implementation, designing the diameter of the bottom chord steel bar of the target steel bar truss based on the target relationship includes:

[0123] Obtaining a design stress value of the upper chord steel bars of the target steel truss, and calculating a cross-sectional area of ​​the upper chord steel bars of the target steel truss based on the design stress value and the design compressive strength value of the steel bars;

[0124] Obtaining a design stress value of the bottom chord steel bars of the target steel truss, and calculating a cross-sectional area of ​​the bottom chord steel bars of the target steel truss based on the design stress values ​​of the top and bottom chord steel bars of the target steel truss, a design value of the tensile strength of the steel bars, a cross-sectional area of ​​the top chord steel bars of the target steel truss, and the target reduction factor;

[0125] The diameter of the bottom chord steel bar of the target steel bar truss is obtained based on the cross-sectional area of ​​the bottom chord steel bar of the target steel bar truss.

[0126] Example 4

[0127] The present invention also provides a computer-readable storage medium, which stores one or more programs, and the one or more programs can be executed by one or more processors to implement the steps of the design method for reducing the amount of steel bars used in the lower chord of a composite slab as described above.

[0128] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A design method for reducing the amount of steel bars used in the lower chord of a composite slab, characterized in that: The design method for reducing the amount of steel bars used in the lower chord of the composite slab includes: Constructing a target equilibrium equation, wherein the target equilibrium equation is an axial force equilibrium equation of a plane truss prefabricated bottom plate component in the composite slab during the construction phase; Obtaining a target relationship based on the target equilibrium equation, wherein the target relationship represents a cross-sectional size relationship between an upper chord steel bar and a lower chord steel bar of the steel truss; The diameter of the bottom chord steel bars of the target steel truss is designed based on the target relationship.

2. The design method for reducing the amount of reinforcement used in the lower chord of a composite slab according to claim 1 is characterized in that: The constructing target balance equation includes: A target reduction coefficient is designed, and the target equilibrium equation is obtained based on the target reduction coefficient so that the internal axial force in the cross section of the plane truss precast plate component is balanced. The target reduction coefficient is a reduction coefficient of the tensile stress of the precast bottom plate concrete relative to the design value of the concrete tensile strength.

3. The design method for reducing the amount of reinforcement used in the lower chord of a composite slab according to claim 1 is characterized in that: The target balance equation is: N=A' s in s -A s s s -cbkf t =0; Where N is the design value of the axial force of the plane truss precast plate component, A′ s 、A s are the cross-sectional areas of the upper and lower chord steel bars of the steel truss, σ′ s , σ s are the design values ​​of the stress of the upper and lower chord steel bars of the steel truss, c is the thickness of the precast base plate, b is the spacing between steel trusses, corresponding to the effective precast base plate width of a single steel truss, k is the target reduction factor, f t is the design value of tensile strength of precast base slab concrete.

4. The design method for reducing the amount of reinforcement used in the lower chord of a composite slab according to claim 2 is characterized in that: The design target reduction factor includes: A composite plate geometric model is constructed, and a finite element parametric analysis is performed on the composite plate under different parameters based on the composite plate geometric model and the target equilibrium equation to obtain a solution formula for the target reduction coefficient that satisfies the target equilibrium equation.

5. The design method for reducing the amount of reinforcement used in the lower chord of a composite slab according to claim 4 is characterized in that: The solution formula for the target reduction coefficient is: k=1.927-0.00284h-0.0305d1-0.07d2; Where h is the thickness of the composite slab, d1 and d2 are the diameters of the upper and lower chord steel bars of the steel truss, respectively.

6. The design method for reducing the amount of reinforcement used in the lower chord of a composite slab according to claim 1 is characterized in that: The target relationship is: Among them, A' s 、A s are the cross-sectional areas of the upper and lower chord steel bars of the steel truss, σ′ s , σ s are the design values ​​of the stress of the upper and lower chord steel bars of the steel truss, c is the thickness of the precast base plate, b is the spacing between steel trusses, corresponding to the effective precast base plate width of a single steel truss, k is the target reduction factor, f t is the design value of tensile strength of precast base slab concrete, f y is the design value of steel bar tensile strength.

7. The design method for reducing the amount of reinforcement used in the lower chord of a composite slab according to claim 2, characterized in that: The step of designing the diameter of the bottom chord steel bar of the target steel bar truss based on the target relationship includes: Obtaining a design stress value of the upper chord steel bars of the target steel truss, and calculating a cross-sectional area of ​​the upper chord steel bars of the target steel truss based on the design stress value and the design compressive strength value of the steel bars; Obtaining a design stress value of the bottom chord steel bars of the target steel truss, and calculating a cross-sectional area of ​​the bottom chord steel bars of the target steel truss based on the design stress values ​​of the top and bottom chord steel bars of the target steel truss, a design value of the tensile strength of the steel bars, a cross-sectional area of ​​the top chord steel bars of the target steel truss, and the target reduction factor; The diameter of the bottom chord steel bar of the target steel bar truss is obtained based on the cross-sectional area of ​​the bottom chord steel bar of the target steel bar truss.

8. A design device for reducing the amount of steel bars used in the lower chord of a composite slab, characterized in that: include: An equation construction module is used to construct a target equilibrium equation, wherein the target equilibrium equation is an axial force equilibrium equation of a plane truss prefabricated bottom plate component in a composite plate during the construction phase; a relationship analysis module, configured to obtain a target relationship expression based on the target equilibrium equation, wherein the target relationship expression represents a relationship between the cross-sectional sizes of the upper chord steel bars and the lower chord steel bars of the steel truss; The usage design module is used to design the diameter of the lower chord steel bars of the target steel bar truss based on the target relationship.

9. A terminal, characterized in that: The terminal includes: a processor, a computer-readable storage medium communicatively connected to the processor, the computer-readable storage medium being suitable for storing a plurality of instructions, and the processor being suitable for calling the instructions in the computer-readable storage medium to execute the steps of the design method for reducing the amount of steel bars used in the lower chord of the composite slab as described in any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that The computer-readable storage medium stores one or more programs, and the one or more programs can be executed by one or more processors to implement the steps of the design method for reducing the amount of steel bars used in the lower chord of a composite slab as described in any one of claims 1 to 7.

Images