JP5327647B2 - Damping structure - Google Patents

Description

  The present invention relates to seismic control technology for buildings, and more particularly to a seismic control structure for a computer center that requires high seismic performance.

As is well known, a computer center is required to have a high level of seismic performance against a huge earthquake because it is necessary to reliably prevent damages such as damage to expensive computers or damage to stored data due to an earthquake. It is.
For this reason, the seismic isolation structure that supports seismic isolation of the entire building with seismic isolation devices such as laminated rubber is effective, but conventional seismic isolation structures can cope with horizontal movement during an earthquake, but are not suitable for vertical movement. It is not always perfect because it cannot be dealt with sufficiently.

  In addition, a vibration control structure in which various vibration control dampers are installed in the building is also considered to be effective. For example, it has been studied to obtain a vibration control effect for vertical movement by a vibration reduction mechanism disclosed in Patent Document 1. This is achieved by adding an additional vibration system consisting of an additional beam and a rotary inertia mass damper to the beam to be damped and functioning as a tuned mass damper (TMD). It is designed to control the vertical movement of the beam to be controlled, and is expected to be popular in the future.

JP 2008-115552 A

However, it is assumed that the vibration reduction mechanism disclosed in Patent Document 1 is applied to a general structure of a general structure, and such a vibration reduction mechanism is applied to a special building such as a computer center. It is not realistic to apply it as it is.
In other words, the vibration reduction mechanism as shown in Patent Document 1 is applied without difficulty to a computer center that is usually different from a general building in its basic structure as well as its functions and required performance. In order to function effectively, it is indispensable to develop a comprehensive plan and a special design method including its form and basic structural form in consideration of the special characteristics of a computer center.

  In view of the above circumstances, an object of the present invention is to provide an effective and appropriate vibration control structure for applying a vibration reduction mechanism as disclosed in Patent Document 1 to a computer center.

  The present invention is a seismic control structure applied to a building whose main use is a computer center, and is provided with an equipment floor for installing related facilities on a floor immediately below a reference floor for installing a computer room, the equipment floor In addition, the floor beam of the equipment floor is used as the lower chord material, and the floor beam of the reference floor directly above is used as the upper chord material, and a bundle material and a diagonal material are provided between the lower chord material and the upper chord material. A main truss frame having a size equivalent to the height of the floor is provided, and an additional truss frame that behaves independently of the main truss frame is provided side by side on the main truss frame. A rotary inertia mass damper that is operated by a vertical relative vibration generated between the main truss frame and the additional truss frame at the time of the earthquake, In series with the rotary inertia mass damper The natural frequency of the additional vibration system constituted by the vibration control mechanism and the additional truss frame is changed to the natural frequency in the vertical direction of the main truss frame as the main vibration system. It is characterized by being synchronized.

According to the seismic control structure of the present invention, a facility floor is set immediately below the standard floor where the computer room is installed, and a high-rigidity main truss frame corresponding to the floor height is configured on the facility floor. In addition to being able to reduce vibrations in the computer room, especially vertical vibrations, an additional vibration system that functions as a TMD with an additional truss frame and a vibration control mechanism is provided for the main truss frame. An excellent seismic control effect can be obtained, the response acceleration and response displacement of the main truss frame can be sufficiently reduced, and the high level of seismic performance required for the computer center can be ensured.
In particular, since the damping mechanism functions as a TMD using a rotary inertia mass damper, a large inertia mass can be obtained with only a small mass weight, and thus sufficient without requiring a large additional mass like a conventional general TMD. A great vibration control effect can be obtained.
In addition, the tuning for functioning the damping mechanism by the rotary inertia mass damper as a TMD is based on the inertial mass obtained by the rotary inertia mass damper, the additional truss frame and the tuning according to the vertical rigidity of the main truss frame to be controlled. By setting the overall vertical stiffness by the spring appropriately, it can be performed easily and accurately, and it can effectively deal with a wide range of frequency components according to the assumed earthquake motion. is there.

The embodiment of the damping structure of the present invention is shown and is a figure showing the schematic structure of the frame of the whole building. FIG. It is a figure for demonstrating the basic composition of a frame same as the above. It is a figure which shows the vibration model for an analysis similarly. It is a figure which shows the item of the main truss frame. It is a figure which shows the item of a damping mechanism same as the above. It is a figure which shows an analysis result similarly. It is a figure which shows an analysis result similarly. It is a figure which shows an analysis result similarly.

An embodiment of the vibration control structure of the present invention will be described with reference to FIGS.
FIG. 1 shows a schematic structure of a frame of a computer center to which the vibration control structure of this embodiment is applied. This computer center is based on the fact that an equipment floor 2 for installing a machine room related to the computer room is secured immediately below the reference floor 1 (so-called CPU floor) for installing the computer room.
That is, the computer center of the present embodiment is basically a multi-layered building in which beams 4 on each floor are installed between pillars 3 as in a normal building as shown in FIG. 3A, but a computer room is installed. By setting up a facility floor 2 with a slightly lower floor height on the floor directly below the standard floor 1 and arranging the computer room and the machine room on the standard floor 1 and the facility floor 2 respectively, and arranging them vertically The plan is to integrate them functionally.
In the following description, among the beams 4 on each floor of the building, the one provided on the floor of the reference floor 1 is referred to as a floor beam 4a, and the one provided on the floor of the equipment floor 2 is referred to as a floor beam 4b.

  And as for the form of the frame as the structural frame of the entire computer center, the main truss frame 10 and the additional truss frame 20 are installed on the equipment floor 2 as shown in FIG. 1 in order to ensure sufficient seismic performance of the entire frame. At the same time, the main purpose is to install a vibration control mechanism 30 between the main truss frame 10 and the additional truss frame 20.

Specifically, as shown in FIG. 3 (b), the above-mentioned facility floor 2 is provided with studs 11 at a predetermined interval between the floor beam 4a on the reference floor and the floor beam 4b on the facility floor. Braces 12 are provided at important points, and a main truss frame 10 having a size corresponding to the height of the equipment floor 2 is formed as a whole.
In other words, the main truss frame 10 has the floor beam 4a on the reference floor 1 as the upper chord material, the floor beam 4b on the equipment floor as the lower chord material, the middle column 11 as the bundle material therebetween, and the brace 12 as the diagonal material. The main truss frame 10 functions as a structural element of a large beam called a so-called mega beam and has sufficient rigidity and seismic performance by itself.
The upper and lower floor beams 4a and 4b that function as the upper chord member and the lower chord member in the main truss frame 10 may be H-shaped steel as in the case of a normal steel beam, but in this embodiment, the studs that function as bundle members. A steel pipe can be suitably used as 11, and a steel rod or a steel material having an appropriate cross section can be suitably used as the brace 12 functioning as a diagonal member.
In the present embodiment, a maintenance passage is secured in the center of the facility floor 2, and the pillars 11 and braces 12 are omitted from the passage to secure an opening there.
Furthermore, as shown in FIG. 2, a slab 5 may be provided as usual on the floor of the equipment floor 2, but a free access floor is provided on the floor of the reference floor 1 for communication with the equipment floor 2. And good.

Similarly, the above-mentioned equipment floor 2 is provided with an additional truss frame 20 that is structurally insulated from the main truss frame 10 and behaves independently on both sides of the main truss frame 10.
That is, as shown in FIG. 3C, the additional truss frame 20 is spaced from the upper chord member 21 laid between the columns 1 slightly below the floor beam 4a of the reference floor 1 and the intermediate portion of the upper chord member 21. Two bundle members 23 suspended from each other, a lower chord member 22 laid between the bundle members 23, an oblique member 24 laid between both ends of the upper chord member 21 and the lower end of the bundle member 23, It is comprised by.
The bundle members 23 in the additional truss frame 20 are provided at positions on both sides of the bundle member (intermediate column 11) in the main truss frame 10 so as to avoid the passage, and the lower chord is constructed at the lower end of the bundle member 23. A slight clearance is secured between the material 22 and the slab 5 of the equipment floor 2, and the lower chord material 22 is provided in a state of floating on the floor surface.

As shown in FIG. 2A, the additional truss frame 20 is disposed on both sides of the main truss frame 10 with a slight space between them, and the additional truss frames 20 on both sides are illustrated in FIG. 2B. In this way, the connecting members 25 are connected at important points and are structurally integrated, but are structurally insulated from the main truss frame 10 and behave independently of the main truss frame 10 during an earthquake. Is.
In this embodiment, the upper chord member 21, the bundle member 23, the diagonal member 24, and the connecting member 25 constituting the additional truss frame 20 are all made of grooved steel. As shown in FIG. 2, as the lower chord member 22 provided at a position crossing the passage as shown in FIG. 2, double-use flat steel is used for the additional truss frame 20 on both sides so as to straddle it. A crossover plate 6 is provided so as not to hinder traffic in the passage.

Then, as shown in FIG. 2 and FIG. 3 (b), rotary inertia mass dampers 31 are respectively installed downward at the upper ends of the bundle members (intermediate columns 11) of the main truss frame 10 so as to face the passage. A leaf spring as a tuning spring 32 is provided between the upper chord members 21 of the additional truss frame 20 located on both sides of the rotary inertia mass damper 31, and the rotary inertia mass damper 31 is connected to the tuning spring 32. The rotary inertia mass damper 31 and the tuning spring 32 constitute the vibration control mechanism 30 of this embodiment.
The rotary inertia mass damper 31 in this embodiment is of a type that obtains a large rotary inertia mass by rotating a small mass weight (flywheel) via a ball screw mechanism, as shown in Patent Document 1. The rotary inertia mass damper 31 is fixed to the main truss frame 10 and the ball screw mechanism is connected to the additional truss frame 20 via the tuning spring 32, so that the main truss frame 10 and the additional truss can be connected in the event of an earthquake. The vibration control mechanism 30 is activated by relative vibration generated between the frames 20.

  The vibration control structure of the present embodiment constitutes an additional vibration system with the above-described vibration control mechanism 30 and the additional truss frame 20, and adds the additional vibration system to the main truss frame 10 as the main vibration system. By synchronizing the natural frequency in the vertical direction of the additional vibration system with the natural frequency in the vertical direction of the main truss frame 10, the entire additional vibration system functions as a TMD for the main vibration system and has excellent damping effect. Is obtained.

As described above, according to the vibration control structure of the present embodiment, the equipment floor 2 is set immediately below the reference floor 1 for installing the computer room, and the equipment floor 2 has a high rigidity equivalent to the floor height. Since the main truss frame 10 is configured, vibrations in the computer room during an earthquake, in particular, vertical vibrations can be reduced naturally, and in addition to the main truss frame 10, TMD by the additional truss frame 20 and the vibration control mechanism 30 is provided. As an additional vibration system that functions as a large-scale earthquake is provided, an excellent vibration control effect can be obtained even in a large earthquake, and the response acceleration and response displacement of the main truss frame 10 can be sufficiently reduced, which is required for a computer center. High seismic performance can be secured.
In particular, since the damping mechanism 30 functions as a TMD using the rotary inertia mass damper 31, a large inertia mass can be obtained with only a small mass, and thus a large additional mass is not required as in the conventional general TMD. A sufficient vibration control effect can be obtained.
Further, the tuning for causing the damping mechanism 30 to function as the TMD by the rotary inertia mass damper 31 is performed according to the vertical rigidity of the main truss frame 10, the inertia mass obtained by the rotary inertia mass damper 31, the additional truss frame 20, and By appropriately setting the overall vertical rigidity by the tuning spring 32, it is possible to carry out easily and accurately, and it is possible to effectively deal with a wide range of frequency components according to the assumed earthquake motion. it can.

Hereinafter, the effect of the vibration control structure of the present invention is illustrated by time history response analysis.
The seismic damping structure of the present invention is modeled as shown in FIG. 4 and a case is assumed where an evenly distributed load 261 kN / m acts on the upper chord member of the main truss frame 10.
As the specifications of the main truss frame 10, the A type and the B type shown in FIG. The A type was I = 7825500 cm ⁴ and the primary natural frequency was 6.217 Hz, and the B type was I = 5391000 cm ⁴ and the primary natural frequency was 5.16 Hz (see FIG. 5 for other specifications).
Incidentally, each floor loading of standard floor 1 and equipment floor 2 and ^{12kN / m 2, 16kN / m} 2, the deflection constant of the central portion of the main truss Frame 10 in that case is approximately 8 mm.

As shown in Fig. 6, the specifications of the vibration control mechanism 30 have a rotary inertia mass of 9320kg for both the A type and B type, and the vertical rigidity (truss spring) of the additional truss frame 20 is 3.44 x 10 ⁷ N per location. The vertical stiffness is adjusted to 4.02 × 10 ⁷ N / m for the A type and 2.03 × 10 ⁷ N / for the B type by adjusting the plate thickness and shape dimensions of the leaf spring as the tuning spring 32. m was tuned to the primary natural frequency in each case. The attenuation coefficient was 1.82 × 10 ⁵ N / m / s for the A type and 1.52 × 10 ⁵ N / m / s for the B type.

Seismic response analysis by vertical motion is performed for the above model. The structural damping was the initial stiffness proportional type of 2% with respect to the primary natural period. The ticking time was 0.0025 seconds.
The input seismic motion was El Centro UD (multiplying the horizontal motion by 50kine standardized magnification), Taft UD (same as above), and notification wave UD (1995 uses JMA Kobe UD).

The response analysis results for the maximum response acceleration and the maximum response displacement are shown in FIGS. FIG. 9 shows acceleration and displacement response waveforms when the A type is El Centro UD as the input ground motion.
From these results, it can be seen that according to the damping structure of the present invention, a sufficient response reduction effect can be obtained for both acceleration and displacement in the case of non-seismic control.

  The embodiment of the present invention has been described above. However, the above embodiment is merely a preferred example, and the present invention is not limited to the above embodiment, and the main truss frame 10 installed on the equipment floor 2 is added. As long as it does not deviate from the gist of the present invention to intervene the vibration control mechanism 30 using the rotary inertia mass damper 31 between the truss frame 20 and function as TMD, for example, the following suitable as listed below It is possible to make design changes and applications.

Specific configurations of the main truss frame 10 and the additional truss frame 20 are arbitrary, and may be optimally designed according to the scale and form of the entire computer center, the plan plan, and other various conditions.
In particular, in the above embodiment, the main truss frame 10 and the additional truss frame 20 are configured so as not to block the position of the channel because the passage is provided in the center of the equipment floor 2, and the lower truss material of the additional truss frame 20 22 is made of flat steel, but if there is no such need, the position of the bundle material (intermediate column 11) and the diagonal material (brace 12) in the main truss frame 10 as well as the whole of the additional truss frame 20 The form is also arbitrary.
However, since a large number of ducts and cables are installed vertically and horizontally on the facility floor 2, it is not preferable that the machine room is divided by the main truss frame 10 and the additional truss frame 20, and the main truss frame 10 and the additional truss Sufficient space for passing ducts and cables through both frames 20 should be secured. In this regard, if a full-sized beam having a large cross section is provided as the main truss frame 10 and the additional truss frame 20, it is necessary to provide a large number of large-diameter beam through-holes. Since the truss frame is in the form of a beam, there is no need to consider such a through hole, which is extremely reasonable.
In the above embodiment, the additional truss frame 20 is installed on both sides of the main truss frame 10 so that a good balance is naturally obtained. However, this is not necessarily the case and there is a problem in securing the lateral balance. Otherwise, a single additional truss frame 20 may be arranged on one side of the main truss frame 10.

The rotary inertia mass damper 31 constituting the vibration control mechanism 30 is preferably of the type in which a small mass weight is rotated by a ball screw mechanism as in the above embodiment, and in that case, a tuning spring 32 is used as in the above embodiment. Although it is realistic to connect the leaf spring as a ball screw mechanism, the vibration control mechanism 30 in the present invention may be any mechanism that can function as a TMD by using the inertial mass effect to obtain a desired additional mass. As long as that is the case, the specific configuration of the vibration control mechanism 30 is not limited and is arbitrary.
Of course, the capacity, installation position, and number of installations of the vibration control mechanism 30 may be optimally designed so as to obtain a desired vibration control effect in consideration of the forms of the main truss frame 10 and the additional truss frame 20. For example, in the above embodiment, two sets of vibration control mechanisms 30 are installed on both sides of the passage just below the upper chord material (floor beam 4a of the reference floor 1) of the main truss frame 10, but the number of vibration control mechanisms 30 is installed. It may be appropriately increased or decreased as necessary, and the installation position is also arbitrary, for example, it may be installed near the floor surface of the equipment floor 2, and in that case, the bundle of the main truss frame 10 (intermediate column 11) The vibration control mechanism 30 may be interposed between the lower chord member and the lower chord member (the floor beam 4b of the equipment floor 2) and the lower chord member 22, the bundle member 23 or the diagonal member 24 of the additional truss frame 20.
Furthermore, the form of installation of the vibration control mechanism between the main truss frame 10 and the additional truss frame 20 is also arbitrary. For example, contrary to the above embodiment, the rotary inertia mass damper 31 is attached to the additional truss frame 20. Fixing and connecting the tuning spring 32 to the main truss frame 10 works similarly.

1 Standard floor 2 Equipment floor 3 Column 4 Beam 4a Floor beam on the standard floor (upper chord material of main truss frame)
4b Floor beams on equipment floor (lower truss material of main truss frame)
5 Slab 6 Crossing board 10 Main truss frame 11 Space pillar (bundle)
12 Braces (diagonal)
20 Additional truss frame 21 Upper chord material 22 Lower chord material 23 Bundling material 24 Diagonal material 25 Connecting material 30 Damping mechanism 31 Rotating inertia mass damper 32 Tuning spring

Claims (1)

It is a seismic control structure that is applied to buildings that mainly use computer centers,
There is an equipment floor for installing related equipment on the floor directly below the standard floor for installing the computer room.
In the equipment floor, by using the floor beam of the equipment floor as a lower chord material and by setting the floor beam of the reference floor directly above the upper chord material as a bundle material and a diagonal material between the lower chord material and the upper chord material, Establish a main truss frame with the same dimensions as the floor height of the equipment floor,
An additional truss frame that behaves independently of the main truss frame is provided side by side with the main truss frame, and a vibration control mechanism is interposed between the main truss frame and the additional truss frame,
The damping mechanism includes a rotary inertia mass damper that is operated by a vertical relative vibration generated between the main truss frame and the additional truss frame during an earthquake, and a tuning spring connected in series to the rotary inertia mass damper. The natural frequency of the additional vibration system composed of the vibration control mechanism and the additional truss frame is synchronized with the natural frequency in the vertical direction of the main truss frame as the main vibration system. Characteristic damping structure.

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