Method for predicting vibration of dry-type joined floor

Abstract

To provide a vibration prediction method of a dry joint floor capable of performing vibration prediction with high accuracy by a relatively simple method without performing highly accurate vibration analysis requiring time and labor in vibration prediction of the dry joint floor.SOLUTION: A vibration prediction method of a dry joint floor in which an end portion of a floor panel is joined by a joint metal fitting to a plurality of beams juxtaposed at intervals, wherein the vibration prediction is performed by the following formula (X): SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a method for predicting vibrations of a dry-jointed floor. [Background technology]

[0002] Floor vibration caused by people walking is a daily occurrence and can lead to strong discomfort for residents, so it is essential to consider minimizing floor vibration as much as possible when designing floors. A person's walking pace is generally around 2Hz, and it is considered desirable to design floors with a natural frequency of 10Hz or higher to avoid harmonic vibrations of 4Hz, 6Hz, and 8Hz.

[0003] In industrialized housing, dry joining is sometimes used to join beams and floor panels in order to improve construction efficiency, but this dry joining secures the beams and floor panels less firmly than wet joining, and currently there is no established method for analytically evaluating floor vibration.For example, there is a method for evaluating floor vibration of a dry-jointed floor in which a pair of opposing end sides (e.g., short sides) of a rectangular floor panel in plan view is placed on two beams placed next to each other, and the ends of the beam and floor panel are joined with joint metal fittings, while the other pair of end sides (e.g., long sides) are free and not fixed to the beams.

[0004] The magnitude of floor vibrations caused by people walking in a home cannot be easily predicted, and in order to make such predictions, it is common to model the target floor in a computer and perform vibration analysis.However, this creates new challenges, such as the time and effort required for the series of analyses, including modeling, and the cost of the analysis.

[0005] For the above reasons, there is a need for a method for predicting the vibration of dry-jointed floors that can predict vibration with high accuracy in a relatively simple manner, without having to perform highly accurate vibration analysis, which requires time and effort.

[0006] Here, a floor vibration analysis system is proposed in Patent Document 1. This floor vibration analysis system is a floor vibration analysis system that analyzes vibrations at vibration evaluation points present in an evaluation area that is rectangular in plan view and includes a beam structure in which minor beams are arranged in a space surrounded by major beams of a steel-framed building, and a rectangular floor slab supported by the beam structure. This floor vibration analysis system calculates the vertical acceleration of a time-varying vibration evaluation point when a time-varying excitation force acts as an external force at the vibration evaluation point in an evaluation area where a partition wall is located, and is equipped with a mass calculation unit that calculates the mass at the vibration of the vibration evaluation point from the weight of the floor slab of the evaluation area acting on the beam structure, a spring constant calculation unit that calculates the natural frequency of the floor in the evaluation area based on information about the beam structure and information about the floor slab and calculates the spring constant at the vibration of the vibration evaluation point based on the natural frequency, a damping constant calculation unit that calculates the damping constant at the vibration of the vibration evaluation point from at least information about the partition wall, and an acceleration calculation unit that calculates the acceleration of the time-varying vibration evaluation point as the vibration of a one-degree-of-freedom system of the floor slab and beam structure based on the time-varying excitation force, spring constant, mass, and damping constant. [Prior art documents] [Non-patent literature]

[0007] [Patent Document 1] Japanese Patent Publication No. 2022-158338 Summary of the Invention [Problem to be solved by the invention]

[0008] The floor vibration analysis system described in Patent Document 1 is said to be able to analyze floor vibrations of a building while taking into account the effects of partition walls. However, it is necessary to build a new system to analyze floor vibrations, and it is difficult to say that vibration prediction can be performed with high accuracy using a relatively simple method.

[0009] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a method for predicting the vibration of dry-jointed floors that can predict vibration with high accuracy in a relatively simple manner, without performing highly accurate vibration analysis that requires time and effort. [Means for solving the problem]

[0010] In order to achieve the above object, one aspect of the vibration prediction method for a dry-jointed floor according to the present invention is to: A vibration prediction method for a dry-jointed floor in which the ends of floor panels are joined to a plurality of beams arranged side by side at intervals by metal joints, comprising: The vibration prediction is performed by the following formula (X):

[0011]

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[0012] According to this embodiment, by using equation (X) to predict the vibration of a dry-bonded bed, it is possible to predict the vibration of a dry-bonded bed with high accuracy in a relatively simple manner, without having to perform highly accurate vibration analysis, which requires time and effort.

[0013] Here, floor panels that form the dry-jointed floors that are the subject of vibration prediction can be deck plates, plywood (including structural plywood), cross-laminated timber (CLT), laminated veneer lumber (LVL), autoclaved lightweight concrete (ALC), etc. Floor panels include joist floor panels with steel joists (for example, steel joist floor panels), as well as floor panels that do not have joists, such as ALC panels. Steel beams made of shaped steel materials such as H-shaped steel can be used for the beams that are the subject of the beam model.

[0014] Additionally, the beams that support the floor panels include main girders that span between columns and sub-girders that span between main girders, but "multiple beams arranged side by side at intervals" means main girders and sub-girders that are arranged side by side, or sub-girders and sub-girders that are arranged side by side.Multiple floor panels are placed on multiple beams (main girders and sub-girders) made of H-shaped steel or the like that are arranged side by side, and the ends of each floor panel are dry-joined to the beams via metal joints.

[0015] In this embodiment, the vibration of a dry-jointed floor is predicted based on the cumulative deflection of the beams calculated, for example, by structural calculations. The cumulative deflection of the beams in formula (X) is the sum of the deflection of the main beam (including the primary support beam) that supports the sub-beams and the deflection of the sub-beams supported by the main beams, and the vibration of the dry-jointed floor is predicted based on the total deflection of the main beams and sub-beams.

[0016] In addition, structural design engineers responsible for structural calculations for conventional buildings mainly perform structural calculations, and because consideration of environmental vibrations, including walking vibrations, is related to livability, such consideration is limited to important cases, for example, and individual consideration of environmental vibrations is conducted separately from structural calculations and is generally outside the scope of the structural design engineer's responsibilities.In contrast, according to this aspect, the cumulative deflection of the beams calculated by structural calculations can be used to predict the vibration of dry-jointed floors, so structural design engineers can predict the vibration of dry-jointed floors in addition to structural design.

[0017] Another aspect of the vibration prediction method for a dry-jointed floor according to the present invention is to The method is characterized in that a and b are set by performing multiple regression analysis using a plurality of measured values ​​related to floor vibration.

[0018] According to this embodiment, by performing multiple regression analysis using multiple past measurements of floor vibration (measurements of floor vibration in various building properties) and setting the coefficients a and b in formula (X), it is possible to define formula (X) with high accuracy for predicting the vibration of dry-bonded floors.

[0019] In another aspect of the vibration prediction method for a dry-jointed floor according to the present invention, The beams supporting the dry joint floor are: A small beam supported by a pair of girders and on which the dry joint floor is placed, or A sub-beam supported by the primary support beam and the main beam and on which the dry joint floor rests, or A sub-beam supported by a pair of primary support beams and on which the dry joint floor is placed.

[0020] According to this embodiment, the beam used to calculate the cumulative deflection in formula (X) is a sub-beam that supports a dry-jointed floor, and this sub-beam is one of the following: a sub-beam supported by a pair of main beams and on which a dry-jointed floor is placed, a sub-beam supported by a primary support beam and main beam and on which a dry-jointed floor is placed, or a sub-beam supported by a pair of primary support beams and on which a dry-jointed floor is placed.Therefore, the cumulative deflection of the main beams and sub-beams that are joined at both ends of the sub-beam can be used, and it is possible to realize vibration prediction of a dry-jointed floor using the cumulative deflection of the main beams and sub-beams that form horizontal frames of various configurations. [Effects of the Invention]

[0021] As can be understood from the above explanation, according to the vibration prediction method for dry-bonded floors of the present invention, vibration prediction for dry-bonded floors can be performed with high accuracy using a relatively simple method, without having to perform highly accurate vibration analysis, which requires time and effort. [Brief explanation of the drawings]

[0022] [Figure 1] This is a schematic diagram illustrating an example of a method for calculating the cumulative deflection of the main beam and sub-beam supporting the dry-jointed floor. [Figure 2] FIG. 10 is a schematic diagram illustrating another example of a method for calculating the cumulative deflection of the main beam and the secondary beam supporting the dry-jointed floor. [Figure 3A] This is a cross-sectional view of the joint of a dry-jointed floor during a heel vibration test. [Figure 3B] FIG. 10 is a diagram showing a list of test case numbers. [Figure 4] FIG. 10 is a diagram showing the relationship between the cumulative deflection of a beam and the natural frequency, determined by a heel vibration test. DETAILED DESCRIPTION OF THE INVENTION

[0023] An example of a method for predicting vibrations of a dry-bonded floor according to an embodiment will be described below with reference to the accompanying drawings. Note that in this specification and drawings, substantially identical components may be designated by the same reference numerals to avoid redundant explanation.

[0024] [Method for predicting vibration of dry-type jointed floors according to the embodiment] An example of a vibration prediction method for a dry-jointed floor according to an embodiment will be described with reference to Figures 1 to 4. Here, Figures 1 and 2 are both schematic diagrams illustrating an example of a method for calculating the cumulative deflection of a sub-beam supporting a dry-jointed floor. Also, Figure 3A is a cross-sectional view of a joint of a dry-jointed floor in a heel vibration test, and Figure 3B is a diagram showing a list of the number of test cases. Furthermore, Figure 4 is a diagram showing the relationship between the cumulative deflection of the beam and the natural frequency, as determined by the heel vibration test.

[0025] One example of a method for calculating the cumulative deflection of the main and secondary beams supporting a dry-jointed floor is the method shown in Figures 1 and 2.

[0026] The example shown in Figure 1 shows how to calculate the cumulative deflection of a main beam and a secondary beam supporting a dry-jointed floor when both ends of the secondary beam are supported by a pair of main beams.

[0027] Because the lengths of the pair of main girders and the joint positions of the ends of the sub-girders on the pair of main girders are different, the deflection of the sub-girder joint positions on both main girders: δ1 and δ2 are calculated separately, and the average value of these is calculated. After that, the deflection of the sub-girder: δa is calculated from this average value, and the average deflection of the main girders and the deflection of the sub-girder are added to calculate the cumulative deflection of the main girders and sub-girders: δtotal. This δtotal is used as the deflection of the dry-jointed floor supported by the main girders and sub-girders.

[0028] On the other hand, the example shown in Figure 2 shows a method for calculating the cumulative deflection of the main beam and sub-beam supporting a dry-jointed floor when one end of the sub-beam is joined to the main beam at a midpoint, the other end of the sub-beam is joined to the primary support beam at a midpoint, one end of the primary support beam is supported at a midpoint on the main beam, and the other end of the primary support beam is supported by, for example, a column.

[0029] To calculate the deflection of the primary support beam, the deflection of the main girder to which one end is joined (δ3) is calculated, and the deflection of the primary support beam at the position where one end of the sub-beam is joined (δ1) is calculated by dividing the left and right lengths of the primary support beam using the deflection of the main girder (δ3).The deflection of the primary support beam (δb) is then added to this calculation result to calculate the deflection of the primary support beam to which one end of the sub-beam is joined.

[0030] Next, calculate the average of the deflection of the primary support beam and the deflection at the joint of the main beam where the other end of the secondary beam is joined: δ2, and add the deflection of the secondary beam: δa to this average to calculate the cumulative deflection of the main beam and secondary beam: δtotal. This δtotal is used as the deflection of the dry-jointed floor supported by the main beam, primary support beam, and secondary beam.

[0031] Although not shown in the figure, there are cases where both ends of a sub-beam are joined to a primary support beam. In this case, the deflection of the primary support beam as explained with reference to Figure 2 is calculated for each primary support beam, and the deflection of the sub-beam is added to the average value of these to calculate the cumulative deflection of the main beam, primary support beam, and sub-beam.

[0032] To calculate the cumulative deflection of the sub-beams supporting the dry-jointed floor, a structural design engineer can create a beam model in a computer and apply the load (fixed load) of the dry-jointed floor, etc. and the live load, etc. to the sub-beams to calculate the cumulative deflection along with the structural calculations. Alternatively, a structural design engineer can create a beam model as shown in Figures 1 and 2, etc., and calculate the cumulative deflection of the sub-beams by hand, etc.

[0033] Next, the details and results of the heel vibration test will be explained with reference to Figures 3 and 4. The subjects of the test were six three-story heavy-duty steel-frame rigid-frame houses (designed and constructed by the applicant). At the time of the test, finishing materials such as wallpaper and flooring had already been installed, and no fixtures or other furniture were installed inside the rooms. The ALC panels had a maximum width of 0.606 m and a length of 1.82 m, and two sides in the width direction were in contact with the beams via vibration-isolating rubber and fixed with metal joints, as shown in Figure 3A.

[0034] In this heel vibration test, a MEMS acceleration sensor (sensor part: MA352, manufactured by Seiko Epson, resolution 0.06 μG, sampling frequency 500 Hz (200 Hz for some measurements), case and communication part: manufactured by Logical Product) was used as the measuring instrument.

[0035] Heel vibration was performed three times for each test case. The first natural frequency f (hereinafter referred to as the natural frequency) was defined as the frequency showing the first peak value of the Fourier spectrum of the acceleration waveform, and the average value of the three times was used as the result.

[0036] The test results are shown in Figure 4 as the relationship between cumulative deflection and natural frequency. The figure also shows a regression curve. Of the test results, four data points were excluded from the results because there was an exterior wall panel (a resistance element not reflected in cumulative deflection) directly below the measurement point. The cumulative deflection was calculated by using the deflection of the main and secondary beams when subjected to a fixed load + live load calculated in the structural design to calculate the absolute displacement of the beams near the measurement point.

[0037] According to Figure 4, there is a tendency for the natural frequency to decrease as the cumulative deflection increases. In general, it is desirable for floors to have a natural frequency of 10 Hz or higher to avoid vibration problems caused by harmonic resonance when walking. In recent years, even in industrialized housing, there has been a desire to create large spaces using long-span beams, and floors with natural frequencies close to 10 Hz are being designed. Therefore, it is important to estimate the natural frequency at the design stage.

[0038] In practice, it is difficult to estimate the natural frequency of a small detached building compared to a general building, such as the one surveyed in this experiment. However, based on the results shown in Figure 4, it is possible to easily estimate the natural frequency of the floor at the time of design using the following formula (Q).

[0039]

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[0040] The coefficients a and b are set by performing multiple regression analysis using actual measurements of floor vibrations in multiple real properties in the past. In Figure 4, coefficient a is set to 2.97 and coefficient b is set to 12.23.

[0041] From Figure 4, based on the identified regression curve, the natural frequency of the floor is 15 Hz when the cumulative deflection of the beam is 0.8 cm, and when the 95% lower limit curve is applied, the result is slightly below 10 Hz.

[0042] For this reason, when structural design engineers check the natural frequency of a floor in accordance with the structural design, they should use a cumulative deflection of about 1.0 cm as the standard for the beam, and if the cumulative deflection is about 1.0 cm, they can set the natural frequency of the floor to 10 Hz or higher, and can confirm that the design has been designed to minimize floor vibration.

[0043] It should be noted that the present invention is not limited to the configurations shown here, and other embodiments may be possible in which other components are combined with the configurations described in the above embodiments. In this regard, the present invention can be modified within the scope of the present invention, and can be appropriately determined depending on the application form.

Claims

1. A vibration prediction method for a dry-jointed floor in which the ends of floor panels are joined to a plurality of beams arranged side by side at intervals by metal joints, comprising: A method for predicting vibration of a dry-bonded floor, characterized in that the vibration prediction is performed using the following formula (X). [Equation 1]

2. 2. The method for predicting vibration of a dry-jointed floor according to claim 1, wherein a and b are set by performing multiple regression analysis using a plurality of measured values ​​of floor vibration.

3. The beams supporting the dry joint floor are: A small beam supported by a pair of girders and on which the dry joint floor is placed, or A sub-beam supported by the primary support beam and the main beam and on which the dry joint floor rests, or The method for predicting vibration of a dry-jointed floor as described in claim 1 or 2, characterized in that the dry-jointed floor is one of a pair of primary support beams and a sub-beam on which the dry-jointed floor is placed.

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