Optimal design method of polyurethane vibration isolation for structural raft based on uneven distribution of bearing capacity

Abstract

The present invention provides a structural raft polyurethane vibration isolation optimization design method based on uneven distribution of bearing capacity, characterized in that it includes: (a) determining a preliminary design scheme of a polyurethane vibration isolation layer according to a design scheme of a building structure; (b) using a finite element analysis method to perform a refined calculation of the structural raft bearing capacity of the building structure, including calculation of the deformation stiffness of the raft under the block column nodes; (c) determining the thickness of the polyurethane vibration isolation layer in each block area according to the calculation result of step (b); and (d) based on the thickness determined in step (c), further optimizing the preliminary design scheme of step (a) to meet the vibration isolation requirements. Based on the principle of uneven distribution of the bearing capacity of a building structure, the present invention takes into account the consistent vertical deformation conditions of the raft construction, optimizes and adjusts the size, thickness and layout of the polyurethane vibration isolation pad, and makes the vibration isolation measures of the building more economical and reasonable.

Description

Technical Field

[0001] The invention belongs to the technical field of building structure vibration control, and in particular relates to a structural raft slab polyurethane vibration isolation optimization design method based on uneven distribution of bearing capacity. Background Art

[0002] At present, in actual projects, when raft foundation is used for subway buildings, polyurethane vibration isolation pads are often used. When using this method, most people rely on experience to use a uniform polyurethane thickness layout, but the bearing capacity distribution at different positions in actual projects is uneven. At the same time, most polyurethanes are too thick, and there is still a large amount of waste for vibration reduction. Or after using a uniform polyurethane thickness, it is bound to lead to insufficient thickness of polyurethane in some parts to meet the vibration resistance requirements. Therefore, the uniform polyurethane specifications used in traditional projects will cause great waste of resources or fail to meet the vibration reduction requirements. At the same time, the price of one square meter of polyurethane material is about 2,000 yuan. If a uniform polyurethane material is used, it will cost a lot of money, which is difficult for the owner to accept.

[0003] When using polyurethane vibration isolation design for raft foundation for subway superstructures, the traditional solution relies solely on experience to determine a uniform thickness. However, the bearing capacity distribution in actual engineering is definitely uneven, which will cause inconsistent deflection deformation in various parts, and then lead to uneven settlement of the bottom of the building, which will have a huge impact on the durability of the building structure. At the same time, it will cause uneven stiffness waste and stiffness loss in different parts of the raft foundation, causing a certain degree of change in the resistance of the structure.

[0004] When the raft foundation polyurethane vibration isolation design is adopted for the subway superstructure, the existing projects generally directly determine the thickness of the polyurethane vibration isolation layer based on experience and uniformly lay it. However, due to the complex stress environment of the actual building, the load combination forms are complex and varied, resulting in different loads on different parts of the raft foundation. At the same time, due to the use of a polyurethane vibration isolation layer of uniform thickness, the deformation of the polyurethane vibration isolation layer in different parts is inconsistent. At the same time, due to the inconsistent bearing capacity of different parts, a large thickness of some parts of the polyurethane is not utilized, or the thickness of the polyurethane in some positions cannot meet the vibration reduction requirements. Therefore, the traditional layout plan relying on experience is neither scientific nor reasonable, and will also cause huge waste.

[0005] Therefore, new technologies and methods are needed to solve at least part of the above problems existing in the prior art. Summary of the invention

[0006] In view of the problems of performance mismatch and material waste in the current method of placing polyurethane vibration isolation pads under raft foundation to reduce the vibration hazards of subway superstructures, through optimization calculation, the vibration isolation pads are thickened under the foundation with large force, and the thickness of the vibration isolation pads is reduced under the foundation with small force. This avoids the problem of large economic losses caused by laying all polyurethane vibration isolation pads of the same thickness, thereby improving the economy of this method.

[0007] According to one aspect of the present invention, a method for optimizing the design of polyurethane vibration isolation of a structural raft based on uneven distribution of bearing capacity is provided, comprising:

[0008] (a) Determine the preliminary design of the polyurethane vibration isolation pad according to the design of the building structure;

[0009] (b) Using the finite element analysis method, the structural raft bearing capacity of the building structure is refined, including the calculation of the deformation stiffness of the raft under the block column nodes;

[0010] (c) determining the thickness of the urethane vibration isolation layer in each block area according to the calculation result of step (b); and

[0011] (d) Based on the thickness determined in step (c), further optimize the preliminary design of step (a) to meet the vibration isolation requirements.

[0012] According to an embodiment of the present invention, the finite element analysis method of step (b) includes vibration testing of the vibration source, finite element numerical modeling, and vibration allowable target confirmation.

[0013] According to an embodiment of the present invention, step (b) includes calculating the displacement difference of each node, and step (c) quantifies the design thickness of the polyurethane according to the displacement difference, thereby ensuring coordinated deformation of the displacement of each node.

[0014] According to an embodiment of the present invention, the structural raft polyurethane vibration isolation optimization design method based on uneven distribution of bearing capacity also includes a step (e) after step (d): performing a cost budget analysis, locally optimizing the adjustment range until the cost requirements are met, and determining the final optimization design scheme.

[0015] According to the embodiment of the present invention, the urethane vibration isolation layer comprises a polyurethane elastic vibration damper, studs fixed to two ends of the elastic vibration damper, and a pressing plate pre-buried in the elastic vibration damper and integrated with the two end studs.

[0016] The technology of the present invention can be mainly applied to building structures with high requirements for environmental vibration and whose foundation form is a raft foundation; it can be used as a basis for selecting the thickness of the polyurethane vibration isolation pad on the raft foundation in such projects. When the system is used, it is necessary to calculate the displacement of each node under the raft foundation based on the basic mechanical principles and the finite element method, and arrange polyurethane of different thicknesses under it to ensure that the displacement of the lower part of the foundation is roughly equal. The technology has the following advantages:

[0017] (1) Reasonable use of materials and saving investment. The present invention uses the finite element analysis method to calculate the displacement difference of each node of the base and quantify the design thickness of the polyurethane. When the system is disturbed, it can ensure the coordinated deformation of the displacement of each node. Compared with the traditional method of using uniform thickness of polyurethane materials for paving, the amount of materials used is greatly reduced, the investment is minimized, and the project cost is saved.

[0018] (2) Scientific and reasonable design. By using modular polyurethane vibration isolation pads, through detailed analysis, calculation of material consumption, combined with theoretical demonstration and repeated adjustments of experimental verification, the displacement of the bottom of the raft foundation can be kept within the same order of magnitude, without the need for large-scale centralized configuration of vibration isolation pads, thus avoiding the incoordination of displacement at each point, the generation of internal forces, the increase of unnecessary loads, and the loss of structural stiffness.

[0019] (3) The vibration isolation pad material is highly applicable. The displacement difference calculated based on the basic mechanical principles can make the displacement of the raft bottom continuous and not much different. The specifications and types of vibration isolation pad materials laid on the bottom of different types of raft foundations are basically the same, and the material supplier only needs to quantify production based on thickness. Therefore, the vibration isolation pad material of the entire system is highly applicable, which is convenient for the same polyurethane material and the same standard configuration to be used in various projects or replaced during the operation and maintenance phase. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Hereinafter, some specific embodiments of the present invention will be described in detail in an exemplary and non-limiting manner with reference to the accompanying drawings. The same reference numerals in the accompanying drawings indicate the same or similar components or parts. It should be understood by those skilled in the art that these drawings are not necessarily drawn to scale. The objects and features of the present invention will become more apparent in view of the following description in conjunction with the accompanying drawings, in which:

[0021] Figure 1 A schematic diagram of a flow chart of a structural raft polyurethane vibration isolation optimization design method based on uneven distribution of bearing capacity according to one embodiment of the present invention;

[0022] Figure 2 The figure is a schematic diagram of a structural raft polyurethane vibration isolation design structure based on uneven distribution of bearing capacity according to one embodiment of the present invention, and shows polyurethane vibration isolation pads of different thicknesses. DETAILED DESCRIPTION

[0023] The following further describes a vibration control structure and design method for a subway adjacent to an ancient building according to the present invention in conjunction with the accompanying drawings. The following description is merely exemplary in nature and is not intended to limit the present invention.

[0024] Figure 1 A schematic diagram of a flow chart of a structural raft polyurethane vibration isolation optimization design method based on uneven distribution of bearing capacity according to one embodiment of the present invention; Figure 2 The schematic diagram of the polyurethane vibration isolation design structure of the structural raft based on uneven distribution of bearing capacity according to one embodiment of the present invention. Figure 1-2 According to the structural raft polyurethane vibration isolation optimization design method based on uneven distribution of bearing capacity of the present invention, firstly, based on the design scheme of the building structure, a preliminary design scheme of the polyurethane vibration isolation pad is determined by using a traditional method; then, a finite element analysis method is used to perform a refined calculation of the bearing capacity of the structural raft (10) of the building structure, including calculation of the deformation stiffness of the raft under the node of the block column (20), for example, by performing a refined calculation through vibration testing of the vibration source, finite element numerical modeling, and vibration allowable target confirmation; the displacement difference of each node is calculated, and the design thickness of the polyurethane pad (30) is quantified according to the displacement difference, and the thickness of the polyurethane vibration isolation pad in each block area is determined, thereby further optimizing the preliminary design scheme to ensure the coordinated deformation of the displacement of each node.

[0025] like Figure 2 As shown, the structure involved in the method of the present invention includes a column (column foundation) (20): a self-contained foundation for a single column or a tall structure; a raft (10) (raft foundation): composed of a bottom plate, a beam, etc. The building load is large and the foundation bearing capacity is weak. A concrete bottom plate raft is often used to bear the building load and form a raft foundation. It has good integrity and can well resist uneven settlement of the foundation; and a polyurethane vibration isolation pad (30): the polyurethane vibration isolation pad can be used in the prior art, for example, it can include a polyurethane elastomer, in which a pressure plate that is integrated with the studs at both ends is pre-embedded, and is integrated with the elastic vibration damping body. This scheme adopts this structure, which has high tensile strength and tear resistance, good elasticity, good vibration damping effect, and corrosion resistance, anti-aging performance and overall quality all exceed the existing rubber vibration dampers.

[0026] refer to Figure 1 The structural raft polyurethane vibration isolation optimization design method based on uneven distribution of bearing capacity of the present invention may also include subsequent steps, such as conducting cost budget analysis and local optimization adjustment range until the cost requirements are met. That is, after the vibration isolation requirements are technically met, the parameters can be further adjusted to optimize economically, thereby determining the final optimized design scheme.

[0027] The method of the present invention is clear and has strong executability. It brings good economic effects and greatly saves resources. It is a new and unique solution. In addition, when the raft foundation polyurethane vibration isolation layer is used for the subway building, due to the uneven bearing capacity of the structural foundation, the idea and method of vibration isolation in different areas is adopted. According to the detailed calculation of the structural bearing capacity and the calculation of the deformation stiffness of the raft under the block column node, the polyurethane thickness of the block area is determined to achieve the purpose of vibration isolation in different areas.

[0028] The above is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent structural change made to the above embodiment according to the technical essence of the present invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A structural raft polyurethane vibration isolation optimization design method based on uneven distribution of bearing capacity, characterized in that: include: (a) Determine the preliminary design of the polyurethane vibration isolation pad according to the design of the building structure; (b) Using the finite element analysis method, the structural raft bearing capacity of the building structure is refined, including the calculation of the deformation stiffness of the raft under the block column nodes; (c) determining the thickness of the urethane vibration isolation pad in each block area according to the calculation result of step (b); as well as (d) based on the thickness determined in step (c), further optimizing the preliminary design of step (a) to meet the vibration isolation requirements; Wherein, the finite element analysis method of step (b) includes vibration testing of the vibration source, finite element numerical modeling and vibration allowable target confirmation; Step (b) further comprises calculating the displacement difference of each node, and step (c) quantifying the design thickness of the polyurethane according to the displacement difference, thereby ensuring that the displacement of each node is coordinated and deformed; The method further comprises a step (e) after the step (d): performing a cost budget analysis, locally optimizing and adjusting the scope until the cost requirements are met, and determining a final optimized design solution.

2. The structural raft polyurethane vibration isolation optimization design method based on uneven distribution of bearing capacity according to claim 1 is characterized in that: The urethane vibration isolation layer comprises a polyurethane elastic vibration damping body, studs fixed at two ends of the elastic vibration damping body, and a pressing plate pre-buried in the elastic vibration damping body and integrated with the studs at the two ends.

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