Design method and device for thin prefabricated bottom plate of laminated slab and terminal

Abstract

The invention discloses a design method and device for a thin prefabricated bottom plate of a laminated slab and a terminal.The method comprises the steps that a target span is obtained, the target span is the calculated span of a plane truss prefabricated slab, and a first target steel bar specification is obtained based on the target span; performing stability rechecking on the first target steel bar specification to obtain a second target steel bar specification; and the thin prefabricated bottom plate under the second target steel bar specification is subjected to deformation rechecking, and the target minimum steel bar specification is obtained. The strength, the stability and the deformation of the reinforcing steel bars are rechecked based on the calculated span of the plane truss precast slab, so that the reinforcing steel bars with the minimum specification on the premise of meeting the rechecking condition are obtained, and the effect of reducing the using cost of the reinforcing steel bars as much as possible under the condition of meeting the practical purpose is achieved; and then a thin prefabricated bottom plate product of the laminated slab meeting the target span is designed.

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 a thin prefabricated base plate of a composite plate. 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] However, there is currently no systematic method for selecting the steel bar specifications for the thin prefabricated base plate of the "composite carbon fiber reinforced thin concrete flat steel bar truss composite plate" component.

[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 a thin prefabricated base plate of a composite plate, aiming to solve the problem that there is no systematic method for designing the steel bar specifications of the thin prefabricated base plate of a composite plate 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 method, device, and terminal for designing a thin prefabricated base plate of a composite panel, the method comprising:

[0009] Obtaining a target span, where the target span is a calculated span of the plane truss precast panel, and obtaining a first target steel bar specification based on the target span;

[0010] Performing a stability review on the first target steel bar specification to obtain a second target steel bar specification;

[0011] The deformation of the thin prefabricated base plate under the second target steel bar specification is reviewed to obtain the target minimum steel bar specification.

[0012] In one implementation, obtaining a first target steel bar specification based on the target span includes:

[0013] obtaining a target mid-span bending moment based on the target span;

[0014] Obtaining a steel bar strength verification formula, and calculating the minimum areas of the upper and lower chord steel bars corresponding to the target mid-span bending moment based on the steel bar strength verification formula;

[0015] A corresponding steel bar specification is selected based on the areas of the minimum upper and lower chord steel bars to obtain the first target steel bar specification, where the first target steel bar specification includes the upper and lower chord steel bar specifications and the distance between the upper and lower chord steel bars.

[0016] In one implementation, the steel bar strength verification formula is:

[0017]

[0018] k=1.927-0.00284h-0.0305d1-0.07d2;

[0019] Among them, 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, 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, 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, and f is the maximum value of the precast base plate. t is the design value of tensile strength of precast bottom slab concrete, h is the thickness of composite slab, d1 and d2 are the diameters of upper and lower chord steel bars of steel truss, respectively, and f′ y is the design value of steel bar compressive strength, f y is the design value of steel bar tensile strength.

[0020] In one implementation, performing stability review on the first target steel bar specification to obtain a second target steel bar specification includes:

[0021] Performing a stability review on the first target steel bar specification based on a target stability formula;

[0022] If the first target steel bar specification does not meet the stability requirement, the steel bar specification is gradually increased until the target stability formula is met to obtain the second target steel bar specification.

[0023] In one implementation, the target stability formula is:

[0024]

[0025] N c =σ′ s A′ s ;

[0026] Among them, N c is the design value of the equivalent axial pressure of the steel bar of the steel truss, γ0 is the structural importance factor during the construction stage, and f′ y is the design value of steel bar compressive strength, is the stability factor of the axially compressed member, A′ s is the cross-sectional area of ​​the upper chord steel bars of the steel truss, σ′ s is the design value of the stress in the upper chord of the reinforced truss.

[0027] In one implementation, the step of performing deformation review on the thin prefabricated base plate under the second target steel bar specification to obtain the target minimum steel bar specification includes:

[0028] Performing deformation review on the thin prefabricated base plate under the second target steel bar specification based on the target deformation calculation formula;

[0029] If the deformation of the thin precast base plate under the second target steel bar specification does not meet the deformation limit requirements of the current design code or standard, the steel bar specification is gradually increased until the deformation of the thin precast base plate meets the code limit for mid-span displacement, thereby obtaining the target minimum steel bar specification;

[0030] The target deformation calculation formula is:

[0031]

[0032] Where Δ is the calculated value of the mid-span displacement of the plane truss precast plate, is the axial force of the truss member caused by the unit generalized force, F N is the axial force of the truss member caused by the external load, EA is the axial stiffness of the truss member, and Δ0 is the displacement increment caused by the bending moment of the truss member.

[0033] In one implementation, the method for designing a thin prefabricated base plate of a composite plate further includes:

[0034] Acquire a span set, the span set including calculated spans of a plurality of plane truss precast panels;

[0035] Calculating the minimum steel bar specifications corresponding to the calculated span of each plane truss prefabricated panel in the span set respectively, and obtaining a span-steel bar specification correspondence table;

[0036] When a span to be queried is received, the minimum steel bar specification corresponding to the span to be queried is obtained based on the span-steel bar specification correspondence table.

[0037] A second aspect of the present invention provides a design device for a thin prefabricated base plate of a composite panel, comprising:

[0038] a strength review module, configured to obtain a target span, the target span being a calculated span of the plane truss precast panel, and to obtain a first target steel bar specification based on the target span;

[0039] a stability review module, configured to perform a stability review on the first target steel bar specification to obtain a second target steel bar specification;

[0040] The deformation review module is used to review the deformation of the thin prefabricated base plate under the second target steel bar specification to obtain the target minimum steel bar specification.

[0041] The third aspect of the present invention provides a terminal, which includes a processor and a computer-readable storage medium communicatively connected to the processor, the computer-readable storage medium is suitable for storing multiple instructions, and the processor is suitable for calling the instructions in the computer-readable storage medium to execute the steps of the design method of the thin prefabricated base plate of the composite plate as described in any one of the above items.

[0042] 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 method for designing a thin prefabricated base plate of a composite plate as described in any of the above items.

[0043] Compared with the prior art, the present invention provides a design method, device and terminal for a thin prefabricated base plate of a composite plate. The design method for the thin prefabricated base plate of the composite plate obtains a target span, which is the calculated span of a plane truss prefabricated plate. Based on the target span, a first target steel bar specification is obtained, and then the stability of the first target steel bar specification is reviewed to obtain a second target steel bar specification. Finally, the thin prefabricated base plate under the second target steel bar specification is subjected to a deformation review to obtain a target minimum steel bar specification. The design method for the thin prefabricated base plate of the composite plate proposed by the present invention reviews the strength, stability and deformation of the steel bars based on the calculated span of the plane truss prefabricated plate, thereby obtaining steel bars with the minimum specifications that meet the review conditions and usage specifications, thereby achieving the effect of minimizing the cost of steel bar use while meeting practical purposes, and thus designing a thin prefabricated base plate product for the composite plate that meets the target span. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 A flow chart of an embodiment of a method for designing a thin prefabricated base plate of a composite slab provided by the present invention;

[0045] Figure 2 A cross-sectional view of a planar truss prefabricated bottom plate component of a composite slab according to an embodiment of the method for designing a thin prefabricated bottom plate of a composite slab provided by the present invention;

[0046] Figure 3 A concrete stress-strain curve diagram of an embodiment of the design method of a thin prefabricated base plate of a composite slab provided by the present invention;

[0047] Figure 4 A structural principle diagram of an embodiment of a design device for a thin prefabricated base plate of a composite plate provided by the present invention;

[0048] Figure 5 A schematic diagram of the principles of an embodiment of a terminal provided by the present invention. DETAILED DESCRIPTION

[0049] 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.

[0050] 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.

[0051] 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.

[0052] The design method of the thin prefabricated base plate of the composite plate provided by the present invention can be applied to a terminal with computing capabilities. The terminal can execute the design method of the thin prefabricated base plate of the composite plate provided by the present invention to select the smallest specification of steel bars under the premise of meeting the conditions, so as to minimize the cost of using steel bars while achieving practical purposes.

[0053] Example 1

[0054] This embodiment provides a design method for a thin precast base plate for a composite slab. This method uses equilibrium equations to design the diameters of the upper and lower chord steel bars of a target steel truss. This allows for the use of smaller diameter lower chord steel bars in actual operation, effectively reducing the amount of lower chord steel bars used in the composite slab and further reducing the production cost of concrete flat steel truss composite slabs.

[0055] Specifically, if Figure 1 As shown, in one embodiment of the method for designing a thin prefabricated base plate of a composite board provided by the present invention, the design of the thin prefabricated base plate of the composite board includes the following steps:

[0056] S100: Obtain a target span, where the target span is a calculated span of a plane truss precast panel, and obtain a first target steel bar specification based on the target span.

[0057] The obtaining of a first target steel bar specification based on the target span includes:

[0058] S110, obtaining a target mid-span bending moment based on the target span;

[0059] S120: Obtain a reinforcement strength verification formula, and calculate the minimum areas of the upper and lower chord reinforcement corresponding to the target mid-span bending moment based on the reinforcement strength verification formula;

[0060] S130. Select corresponding steel bar specifications based on the areas of the minimum upper and lower chord steel bars to obtain the first target steel bar specifications, where the first target steel bar specifications include the upper and lower chord steel bar specifications and the distance between the upper and lower chord steel bars.

[0061] The obtaining of a target mid-span bending moment based on the target span includes:

[0062] In the case of a single span and simply supported at both ends, the target mid-span bending moment is calculated based on the bending moment formula;

[0063] The bending moment formula is:

[0064]

[0065] Among them, M is the design value of the bending moment of the plane truss precast plate component, q is the external load, and L is the calculated span of the plane truss precast plate.

[0066] The steel bar strength verification formula is:

[0067]

[0068] k=1.927-0.00284h-0.0305d1-0.07d2;

[0069] Among them, 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, 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, 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, and f is the maximum value of the precast base plate. t is the design value of tensile strength of precast bottom slab concrete, h is the thickness of composite slab, d1 and d2 are the diameters of upper and lower chord steel bars of steel truss, respectively, and f′ y is the design value of steel bar compressive strength, f y is the design value of steel bar tensile strength.

[0070] Specifically, to address the space loss and cost increase caused by the redundant thickness of the prefabricated layers of traditional composite panels, the existing technology uses a "composite carbon fiber reinforced thin concrete flat steel truss composite panel" component to reduce the thickness of the prefabricated base plate from 60mm to 30mm, a 50% reduction in thickness. This revolutionary design not only reduces the component's own weight by 18% through material optimization, but also relies on a flat truss structure to replace the traditional triangular truss, increasing component transportation efficiency by 40%. In terms of material innovation, a fine stone concrete casting process is used, and a carbon fiber / basalt composite mesh with a pore size of 30mm×30mm is embedded. This composite reinforcement system increases the crack resistance of the prefabricated base plate by 3 times, the bending bearing capacity by 25%, and the ductility index by 1.8 times that of traditional components, effectively solving the technical problem of thin components being prone to cracking.

[0071] Reference Figure 2 , Figure 2 This is a cross-sectional view of the new composite slab component. 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 within the precast slab and provided with a 15mm adjustable protective layer. The web reinforcement extends to form a 40-50mm foot 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 controls positioning accuracy within ±2mm. Second, the close-fitting installation process eliminates joints between panels. The precast slab's four-sided design eliminates reinforcement, reducing formwork usage by 70% and shortening 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%, and 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 component of this technical system is the "composite carbon fiber reinforced thin concrete flat steel truss composite plate". Its steel bar laying method is fully compatible with the cast-in-place plate, and 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.

[0072] 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.

[0073] For this new type of composite slab, the conventional approach 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:

[0074]

[0075] 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 y is 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 and finite element analysis results show that the stresses on the top and bottom chords of the steel trusses are different.

[0076] However, in this embodiment, component testing revealed that the specimen exhibited buckling failure characteristics of the upper chord reinforcement. Notably, no visible cracks appeared at the bottom of the thin precast slab throughout the entire test. This phenomenon demonstrates the significant role played by the composite carbon fiber mesh in improving the ductile deformation capacity and crack resistance of concrete. It also demonstrates that the stress on the upper chord reinforcement of a steel truss is greater than that on the lower chord reinforcement. Therefore, the amount of lower chord reinforcement can be appropriately reduced without affecting the overall performance, thereby reducing the manufacturing cost of the composite slab.

[0077] Based on this, in this embodiment, a target equilibrium equation is constructed using a plastic design approach, assuming that the entire cross-section of the precast concrete floor is uniformly stressed and that its tensile stress is k times the design tensile strength value. In this embodiment, k is a target reduction factor. Specifically, the target reduction factor is designed to reduce the axial force of the planar truss precast floor components to zero based on the target reduction factor, resulting in the target equilibrium equation. The target reduction factor represents the reduction factor of the tensile stress of the precast floor concrete relative to the design tensile strength of the concrete.

[0078] Therefore, in this embodiment, the equilibrium equation can be expressed as:

[0079] N=A' s σ′ s -A s σ s -cbkf t =0;

[0080]

[0081] That is, the target balance equation is:

[0082] N=A′ s σ′ s -A s σ s -cbkf t =0;

[0083] 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 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, and f is the maximum value of the precast base plate. t is the design value of tensile strength of precast base slab concrete.

[0084] Then, the target reduction coefficient is designed by finite element parametric analysis and numerical fitting. Specifically, by constructing a geometric model of the composite plate, finite element parametric analysis is performed on the composite plate under different parameters based on the geometric model of the composite plate and the target equilibrium equation, and the solution formula for the target reduction coefficient that satisfies the target equilibrium equation is obtained.

[0085] Specifically, corresponding to different parameters L, h, d1, and d2, L is the calculated span 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.

[0086] 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 reversely calculated according to the target equilibrium equation to obtain many sets of coefficients k. Finally, a genetic algorithm is used to establish a functional relationship between k and parameters h, d1, and d2 to describe how the coefficient k changes with the changes in parameters h, d1, and d2.

[0087] Specifically, according to the results of finite element parametric analysis, the solution formula of the target reduction coefficient obtained by numerical fitting is:

[0088] k=1.927-0.00284h-0.0305d1-0.07d2;

[0089] 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.

[0090] Then, based on the target equilibrium equation and the upper chord reinforcement design formula, the design value formula of the lower chord reinforcement stress of the reinforced truss can be obtained as follows:

[0091]

[0092] Based on this, the final formula for rechecking the steel bar strength is:

[0093]

[0094] k=1.927-0.00284h-0.0305d1-0.07d2;

[0095] Among them, 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, 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, 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, and f is the maximum value of the precast base plate. t is the design value of tensile strength of precast bottom slab concrete, h is the thickness of composite slab, d1 and d2 are the diameters of upper and lower chord steel bars of steel truss, respectively, and f′ y is the design value of steel bar compressive strength, f y is the design value of steel bar tensile strength.

[0096] In this way, the minimum areas of the top and bottom chords that can be used while meeting the target mid-span bending moment can be calculated based on the reinforcement strength verification formula. The minimum diameters of the top and bottom chords are derived based on the minimum areas, and the corresponding rebar specifications can be selected. The top and bottom chord specifications corresponding to the minimum diameters of the top and bottom chords are the first target rebar specifications.

[0097] S200: Perform stability review on the first target steel bar specification to obtain a second target steel bar specification.

[0098] The step of performing stability review on the first target steel bar specification to obtain a second target steel bar specification includes:

[0099] S210, performing stability review on the first target steel bar specification based on a target stability formula;

[0100] S220. If the first target steel bar specification does not meet the stability requirement, the steel bar specification is gradually increased until the target stability formula is met, thereby obtaining the second target steel bar specification.

[0101] Specifically, after obtaining the first target steel bar specification based on the steel bar strength verification formula, the stability of the first target steel bar specification is verified based on the target stability formula. In other words, the first target steel bar specification is substituted into the target stability formula to check whether it satisfies the stability requirement.

[0102] In this embodiment, the target stability formula is:

[0103]

[0104] N c =σ′ s A′ s ;

[0105] Among them, N c is the design value of the equivalent axial pressure of the steel bar of the steel truss, γ0 is the structural importance factor during the construction stage, and f′ y is the design value of steel bar compressive strength, is the stability factor of the axially compressed member, A′ s is the cross-sectional area of ​​the upper chord steel bars of the steel truss, σ′ s is the design value of the stress in the upper chord of the reinforced truss.

[0106] In this embodiment, the stability coefficient of the axially compressed member is It is determined based on the current standard "Steel Structure Design Standard" GB50017.

[0107] Specifically, referring to the cross-section of the rolled round tube, the cross-section classification of the steel bar can adopt the Class A cross-section. The calculated length of the compressive web reinforcement is the inter-section length of the bar. When the diameter of the upper chord steel bar is 8mm, the calculated length of the upper chord steel bar is 0.9 times the inter-section length of the bar; when the diameter of the upper chord steel bar is 10mm, the calculated length of the upper chord steel bar is 1.1 times the inter-section length of the bar; when the diameter of the upper chord steel bar is 12mm, the calculated length of the upper chord steel bar is 1.3 times the inter-section length of the bar. Specifically, the calculated length of the steel bar is not the geometric length of the component (usually refers to the apparent length of the component that can be measured and seen), but the theoretical calculated length l0 that needs to be determined by calculation, and then the turning radius i of the steel bar is determined according to the cross-sectional geometric information such as the diameter of the steel bar, and then the slenderness ratio λ=l0 / i is obtained, and then the slenderness ratio is checked in the appendix of the "Steel Structure Design Standard" GB50017 to obtain the stability coefficient. Therefore, the calculation length is a key parameter for stable calculation.

[0108] Based on this, if the first target steel bar specification does not meet the stability requirement, the steel bar specification is gradually increased until the target stability formula is met, thereby obtaining the second target steel bar specification. Specifically, the steel bar specification is gradually increased according to the existing steel bar specifications (6, 8, 10, 12, etc.) until the stability requirement is met, thereby obtaining the second target steel bar specification.

[0109] S300: Perform deformation review on the thin prefabricated base plate under the second target steel bar specification to obtain a target minimum steel bar specification.

[0110] The deformation review of the thin prefabricated base plate under the second target steel bar specification to obtain the target minimum steel bar specification includes:

[0111] S310, performing deformation review on the thin prefabricated base plate under the second target steel bar specification based on a target deformation calculation formula;

[0112] S320: If the deformation of the thin precast base plate under the second target steel bar specification does not meet the deformation limit requirements of the current design code or standard, gradually increase the steel bar specification until the deformation of the thin precast base plate meets the code limit for mid-span displacement, thereby obtaining the target minimum steel bar specification.

[0113] The target deformation calculation formula is:

[0114]

[0115] Where Δ is the calculated value of the mid-span displacement of the plane truss precast plate, is the axial force of the truss member caused by the unit generalized force, F N is the axial force of the truss member caused by the external load, EA is the axial stiffness of the truss member, and Δ0 is the displacement increment caused by the bending moment of the truss member.

[0116] Specifically, after the second target steel bar specification is determined based on the target stability formula, the deformation of the thin precast base plate corresponding to the second target steel bar specification is verified based on the target deformation calculation formula. In other words, the second target steel bar specification is substituted into the target deformation calculation formula to check whether it meets the deformation requirements.

[0117] Specifically, because the stress on the plane truss precast slab composite components in the "composite carbon fiber reinforced thin concrete plane steel bar truss composite slab" does not conform to the plane section assumption, the deflection cannot be directly calculated based on the equivalent bending stiffness of the solid web section. By analyzing the stress state, the displacement is calculated using the principle of virtual work, where torque and shear are high-order small quantities and are ignored, resulting in the deformation calculation formula:

[0118]

[0119] Where Δ is the calculated value of the mid-span displacement of the plane truss precast plate, is the axial force of the truss member caused by the unit generalized force, F N is the axial force of the truss member caused by external load, EA is the axial stiffness of the truss member, is the bending moment of the truss member caused by the unit generalized force, M0 is the bending moment of the truss member caused by the external load, EI is the bending stiffness of the truss member, Defined as the displacement increment caused by the bending moment in a truss member.

[0120] When the midpoint of the thin precast slab is exactly at the intersection of the upper chord and the web, the All of them are high-order small quantities, Δ0 can be ignored, then the deformation calculation formula can be further simplified to obtain:

[0121]

[0122] In most cases, only the displacement increment of the upper chord of the mid-span interval caused by the bending moment is considered, and the multi-span continuous beam formula is used to simplify the calculation of Δ0, and the target deformation calculation formula is obtained: In the first case, when the midpoint of the thin precast slab is exactly at the midpoint of the length of the upper chord reinforcement bar, In the second case, when the midpoint of the thin precast slab is exactly at 1 / 4 or 3 / 4 of the length of the top chord reinforcement bar,

[0123] Specifically, the contribution of the precast concrete baseplate to the axial stiffness of the bottom chord reinforcement should be considered. During construction, the time from pouring the cast-in-place concrete layer to its solidification into the composite slab is relatively short. Therefore, in this embodiment, the creep effect of concrete is not considered. As can be seen from the aforementioned force analysis, this composite section does not satisfy the planar section assumption, and the area of ​​the precast concrete baseplate cannot be directly converted to the area of ​​the reinforcement based on the ratio of the elastic modulus of concrete to the reinforcement.

[0124] According to the test results, the precast concrete base plate did not crack under large deformation conditions, and the load-displacement curve was basically a straight line. Therefore, it was assumed that the stress-strain curve of the concrete reinforced with the composite carbon fiber mesh was a two-fold line, such as Figure 3 As shown, under the action of mid-span bending moment, the stress of precast bottom slab concrete is f t (design value of tensile strength of precast base slab concrete), the corresponding strain is ε0. Using the principle of energy equality, the axial stiffness EA of the truss member is calculated as follows:

[0125] First, calculate the equivalent elastic modulus of the precast base plate:

[0126]

[0127] Then the precast base plate is converted into steel reinforcement area:

[0128]

[0129] Among them, E eq is the equivalent elastic modulus, E s is the elastic modulus of the steel bar, σ0 and ε0 are the assumed elastic stress and actual strain of the precast bottom plate concrete under the mid-span bending moment. According to the energy equality principle, the two-fold nonlinear curve of concrete is equivalent to the elastic linear curve, and the slope of the equivalent linear curve is the equivalent elastic modulus, A c is the area of ​​precast base plate, A cs A is the converted steel reinforcement area of ​​the precast base plate. s is the cross-sectional area of ​​the bottom chord reinforcement of the steel truss.

[0130] byE=E s , A=A s +A cs The axial stiffness EA of the lower chord member of the truss can be calculated, and the axial stiffness EA of the upper chord member of the truss can be calculated as follows: s A′ s , A′ s is the cross-sectional area of ​​the top chord reinforcement of the steel truss.

[0131] After calculation and verification, the maximum mid-span displacement obtained using the simplified theoretical calculation method is close to the numerical value of the finite element analysis result, with a small error, and can be used for engineering design.

[0132] Based on this, the second target steel bar specification is substituted into the target deformation calculation formula. If the calculated displacement value exceeds the specification limit, the steel bar specification is increased by one or two levels. If the requirement is still not met, the thickness h of the composite slab is increased until the requirement is met. When the thickness h of the composite slab is increased, steps S100-S300 are repeated until the steel bar specification satisfies the steel bar strength verification formula, the target stability formula, and the target deformation formula.

[0133] Furthermore, in this embodiment, the design method of the thin prefabricated base plate of the composite plate further includes:

[0134] Acquire a span set, the span set including calculated spans of a plurality of plane truss precast panels;

[0135] Calculating the minimum steel bar specifications corresponding to the calculated span of each plane truss prefabricated panel in the span set respectively, and obtaining a span-steel bar specification correspondence table;

[0136] When a span to be queried is received, the minimum steel bar specification corresponding to the span to be queried is obtained based on the span-steel bar specification correspondence table.

[0137] Specifically, in more application examples, a span set can be designed in advance, and the span set covers the calculated spans of multiple commonly used plane truss precast panels. Then, the minimum steel bar specifications corresponding to the calculated spans of each plane truss precast panel in the span set are calculated separately. In this way, a span-steel bar specification correspondence table can be obtained, and the span-steel bar specification correspondence table covers the minimum steel bar specifications corresponding to the calculated spans of multiple commonly used plane truss precast panels. This is equivalent to calculating the minimum steel bar specifications corresponding to the calculated spans of commonly used plane truss precast panels in advance and recording them for archiving. In this way, when a span to be queried is received, the steel bar with the smallest specification corresponding to the span to be queried, provided that the conditions are met, can be quickly obtained based on the span-steel bar specification correspondence table, so that the most cost-effective steel bar specifications can be quickly found for production when it is actually used.

[0138] In summary, this embodiment provides a design method for a thin prefabricated base plate of a composite slab, by obtaining a target span, which is the calculated span of a plane truss prefabricated slab, obtaining a first target steel bar specification based on the target span, then performing a stability review on the first target steel bar specification to obtain a second target steel bar specification, and finally performing a deformation review on the thin prefabricated base plate under the second target steel bar specification to obtain a target minimum steel bar specification. The design method for a thin prefabricated base plate of a composite slab proposed in this embodiment, by performing a strength, stability, and deformation review of the steel bar based on the calculated span of the plane truss prefabricated slab, obtains steel bars with the smallest specifications that meet the use conditions and current specifications, thereby achieving the effect of minimizing the cost of steel bar use while meeting practical purposes, and further designing a thin prefabricated base plate product for a composite slab that meets the target span.

[0139] 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.

[0140] 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.

[0141] Example 2

[0142] Based on the above embodiments, the present invention also provides a design device for a thin prefabricated base plate of a composite plate. Figure 4 As shown, the design device of the thin prefabricated bottom plate of the composite plate includes:

[0143] A strength review module is configured to obtain a target span, where the target span is a calculated span of the plane truss precast plate, and obtain a first target steel bar specification based on the target span, as specifically described in the first embodiment;

[0144] a stability review module, configured to perform stability review on the first target steel bar specification to obtain a second target steel bar specification, as specifically described in the first embodiment;

[0145] The deformation review module is used to review the deformation of the thin prefabricated base plate under the second target steel bar specification to obtain the target minimum steel bar specification, as specifically described in the first embodiment.

[0146] Example 3

[0147] Based on the above embodiments, the present invention also provides a terminal, such as Figure 5 As shown, the terminal includes a processor 10 and a memory 20. Figure 5Only 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.

[0148] 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 a thin prefabricated base plate of a composite panel is stored on the memory 20, and the design program 30 for a thin prefabricated base plate of a composite panel can be executed by the processor 10, thereby realizing the design method for a thin prefabricated base plate of a composite panel in the present application.

[0149] In some embodiments, the processor 10 can be a central processing unit (CPU), a microprocessor or other chip, used to run the program code or process data stored in the memory 20, such as executing the design method of the thin prefabricated base plate of the composite plate.

[0150] In one embodiment, when the processor 10 executes the design program 30 of the thin prefabricated base plate of the composite plate in the memory 20, the following steps are implemented:

[0151] Obtaining a target span, where the target span is a calculated span of the plane truss precast panel, and obtaining a first target steel bar specification based on the target span;

[0152] Performing a stability review on the first target steel bar specification to obtain a second target steel bar specification;

[0153] The deformation of the thin prefabricated base plate under the second target steel bar specification is reviewed to obtain the target minimum steel bar specification.

[0154] In one implementation, obtaining a first target steel bar specification based on the target span includes:

[0155] obtaining a target mid-span bending moment based on the target span;

[0156] Obtaining a steel bar strength verification formula, and calculating the minimum areas of the upper and lower chord steel bars corresponding to the target mid-span bending moment based on the steel bar strength verification formula;

[0157] A corresponding steel bar specification is selected based on the areas of the minimum upper and lower chord steel bars to obtain the first target steel bar specification, where the first target steel bar specification includes the upper and lower chord steel bar specifications and the distance between the upper and lower chord steel bars.

[0158] In one implementation, the steel bar strength verification formula is:

[0159]

[0160] k=1.927-0.00284h-0.0305d1-0.07d2;

[0161] Among them, 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, 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, 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, and f is the maximum value of the precast base plate. t is the design value of tensile strength of precast bottom slab concrete, h is the thickness of composite slab, d1 and d2 are the diameters of upper and lower chord steel bars of steel truss, respectively, and f′ y is the design value of steel bar compressive strength, f y is the design value of steel bar tensile strength.

[0162] In one implementation, performing stability review on the first target steel bar specification to obtain a second target steel bar specification includes:

[0163] Performing a stability review on the first target steel bar specification based on a target stability formula;

[0164] If the first target steel bar specification does not meet the stability requirement, the steel bar specification is gradually increased until the target stability formula is met to obtain the second target steel bar specification.

[0165] In one implementation, the target stability formula is:

[0166]

[0167] N c =σ′ s A′ s ;

[0168] Among them, N c is the design value of the equivalent axial pressure of the steel bar of the steel truss, γ0 is the structural importance factor during the construction stage, and f′ y is the design value of steel bar compressive strength, is the stability factor of the axially compressed member, A′ s is the cross-sectional area of ​​the upper chord steel bars of the steel truss, σ′ s is the design value of the stress in the upper chord of the reinforced truss.

[0169] In one implementation, the step of performing deformation review on the thin prefabricated base plate under the second target steel bar specification to obtain the target minimum steel bar specification includes:

[0170] Performing deformation review on the thin prefabricated base plate under the second target steel bar specification based on the target deformation calculation formula;

[0171] If the deformation of the thin precast base plate under the second target steel bar specification does not meet the deformation limit requirements of the current design code or standard, the steel bar specification is gradually increased until the deformation of the thin precast base plate meets the code limit for mid-span displacement, thereby obtaining the target minimum steel bar specification;

[0172] The target deformation calculation formula is:

[0173]

[0174] Where Δ is the calculated value of the mid-span displacement of the plane truss precast plate, is the axial force of the truss member caused by the unit generalized force, F N is the axial force of the truss member caused by the external load, EA is the axial stiffness of the truss member, and Δ0 is the displacement increment caused by the bending moment of the truss member.

[0175] In one implementation, the method for designing a thin prefabricated base plate of a composite plate further includes:

[0176] Acquire a span set, the span set including calculated spans of a plurality of plane truss precast panels;

[0177] Calculating the minimum steel bar specifications corresponding to the calculated span of each plane truss prefabricated panel in the span set respectively, and obtaining a span-steel bar specification correspondence table;

[0178] When a span to be queried is received, the minimum steel bar specification corresponding to the span to be queried is obtained based on the span-steel bar specification correspondence table.

[0179] Example 4

[0180] 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 of the thin prefabricated base plate of the composite plate as described above.

[0181] 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 a thin prefabricated base plate of a composite plate, characterized in that: The design method of the thin prefabricated base plate of the composite plate includes: Obtaining a target span, where the target span is a calculated span of the plane truss precast panel, and obtaining a first target steel bar specification based on the target span; Performing a stability review on the first target steel bar specification to obtain a second target steel bar specification; The deformation of the thin prefabricated base plate under the second target steel bar specification is reviewed to obtain the target minimum steel bar specification.

2. The design method of a thin prefabricated base plate of a composite plate according to claim 1, characterized in that: The obtaining of a first target steel bar specification based on the target span includes: obtaining a target mid-span bending moment based on the target span; Obtaining a steel bar strength verification formula, and calculating the minimum areas of the upper and lower chord steel bars corresponding to the target mid-span bending moment based on the steel bar strength verification formula; A corresponding steel bar specification is selected based on the areas of the minimum upper and lower chord steel bars to obtain the first target steel bar specification, where the first target steel bar specification includes the upper and lower chord steel bar specifications and the distance between the upper and lower chord steel bars.

3. The design method of a thin prefabricated base plate of a composite plate according to claim 2, characterized in that: The steel bar strength verification formula is: k=1.927-0.00284h-0.0305d1-0.07d2; Among them, 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, 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, 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, and f is the maximum value of the precast base plate. t is the design value of tensile strength of precast bottom slab concrete, h is the thickness of composite slab, d1 and d2 are the diameters of upper and lower chord steel bars of steel truss, respectively, and f′ y is the design value of steel bar compressive strength, f y is the design value of steel bar tensile strength.

4. The design method of a thin prefabricated base plate of a composite slab according to claim 1, characterized in that: The step of performing stability review on the first target steel bar specification to obtain a second target steel bar specification includes: Performing a stability review on the first target steel bar specification based on a target stability formula; If the first target steel bar specification does not meet the stability requirement, the steel bar specification is gradually increased until the target stability formula is met to obtain the second target steel bar specification.

5. The design method of a thin prefabricated base plate of a composite slab according to claim 4, characterized in that: The target stability formula is: N c =σ′ s A′ s ; Among them, N c is the design value of the equivalent axial pressure of the steel bar of the steel truss, γ0 is the structural importance factor during the construction stage, and f′ y is the design value of steel bar compressive strength, is the stability factor of the axially compressed member, A′ s is the cross-sectional area of ​​the upper chord steel bars of the steel truss, σ′ s is the design value of the stress in the upper chord of the reinforced truss.

6. The design method of a thin prefabricated base plate of a composite slab according to claim 1, characterized in that: The deformation review of the thin prefabricated base plate under the second target steel bar specification to obtain the target minimum steel bar specification includes: Performing deformation review on the thin prefabricated base plate under the second target steel bar specification based on the target deformation calculation formula; If the deformation of the thin precast base plate under the second target steel bar specification does not meet the deformation limit requirements of the current design code or standard, the steel bar specification is gradually increased until the deformation of the thin precast base plate meets the code limit for mid-span displacement, thereby obtaining the target minimum steel bar specification; The target deformation calculation formula is: Where Δ is the calculated value of the mid-span displacement of the plane truss precast plate, is the axial force of the truss member caused by the unit generalized force, F N is the axial force of the truss member caused by the external load, EA is the axial stiffness of the truss member, and Δ0 is the displacement increment caused by the bending moment of the truss member.

7. The design method of a thin prefabricated base plate of a composite slab according to claim 1, characterized in that: The design method of the thin prefabricated base plate of the composite plate also includes: Acquire a span set, the span set including calculated spans of a plurality of plane truss precast panels; Calculating the minimum steel bar specifications corresponding to the calculated span of each plane truss prefabricated panel in the span set respectively, and obtaining a span-steel bar specification correspondence table; When a span to be queried is received, the minimum steel bar specification corresponding to the span to be queried is obtained based on the span-steel bar specification correspondence table.

8. A design device for a thin prefabricated base plate of a composite plate, characterized in that: include: a strength review module, configured to obtain a target span, the target span being a calculated span of the plane truss precast panel, and to obtain a first target steel bar specification based on the target span; a stability review module, configured to perform a stability review on the first target steel bar specification to obtain a second target steel bar specification; The deformation review module is used to review the deformation of the thin prefabricated base plate under the second target steel bar specification to obtain the target minimum steel bar specification.

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 is suitable for storing multiple instructions, and the processor is suitable for calling the instructions in the computer-readable storage medium to execute the steps of the design method of the thin prefabricated base plate of the composite plate 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 of the thin prefabricated base plate of the composite plate as described in any one of claims 1-7.

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