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Seismic anchoring of computing equipment using the HPPlinth Rack Option Kit

best practice

Abstract.............................................................................................................................................. 2Introduction......................................................................................................................................... 2Structural calculations........................................................................................................................... 3

Inertia data ..................................................................................................................................... 3Anchorage calculations .................................................................................................................... 5

Vertical live load.......................................................................................................................... 5Lateral seismic force...................................................................................................................... 5Calculation for ground-level anchorage force................................................................................... 6Calcualtion for 2ndfloor and above anchorage force........................................................................ 8

Plinth anchoring scenarios .................................................................................................................... 9Plinth anchored on raised flooring...................................................................................................... 9Plinth anchored to solid floor ............................................................................................................. 9

Basic Plinth mounting procedure............................................................................................................ 9Conclusion.......................................................................................................................................... 9For more information.......................................................................................................................... 10Call to Action.................................................................................................................................... 10

Appendix: Plinth kit drawings............................................................................................................. 11

Excellence Winner of STC's InternationalTechnical Publication Competition, 2006
http://www.stc.org/comp/internationalCompetitions01_winners_ITPC.asp


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Abstract

Equipment racks are typically shipped with only basic provisions for stabilization. Rack installations ingeographical areas that present a risk of seismic activity require special consideration by data centerinstallation architects. This paper describes an HP solution for anchoring HP 10000 Series racks toavoid damage or serious injury in the event of building or floor movement. It provides engineeringdrawings, parameters, and calculations to help customers determine how to maximize the stability ofthe racks in their computing facilities.

Introduction

The HP 10000 Series rack is shipped with leveling feet and casters. These basic stabilization featuresare adequate for many installations. However, rack installation in some geographical locations mayrequire further consideration. A floor that shakes or moves due to severe vibrations or seismic activitycan create a catastrophe if heavy equipment is allowed to roll, slide, or fall.

The HP Plinth Rack Option Kit provides a means for anchoring an HP 10000 Series rack to the floorin geographical areas prone to seismic activity. The kit is designed to meet building code guidelinesfor anchoring HP 10000 Series racks for sizes up to 47U (Figure 1). HP Plinth kits are the solution for

physically securing components in geographical areas prone to seismic activity.

Figure 1. HP 10000 Series Racks

Each Plinth kit includes the parts necessary to assemble the Plinth and attach a rack to the Plinth. ThePlinth kit also includes four eyebolts that attach to the top of the rack to allow lifting the rack into placeon top of the Plinth. Before the Plinth can be attached, the rack casters must to be removed.

ot :To secure the Plinth to the floor, additional hardware not provided in thePlinth kit will be required. Drawings included in this document identifyhardware required for various types of installations.


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Structural calculations

ot :The calculations described in this document are based on data obtainedfrom the 1998 California building code, Title 24, Part 2.

Inertia dataThe HP 10000 Series racks are available in various heights of 14U, 22U, 36U, 42U, and 47U. Theinertia data provided in this section are based on a 42U HP 10000 Series rack with the dimensionsand center of gravity shown in Figure 2. Note that this document does not address the Plinth kit and14U rack combination.

Figure 2. Dimensions and center of gravity location for HP 10000 Series 42U rack

2056.5

303.12

600.0

1005.69

919.00445.05

1016.4NOTE: All dimensions given inmillimeters (mm).


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Figure 3 shows the polar moments of inertia for the HP 10000 Series 42U rack.

Figure 3. Polar moments of inertia for HP 10000 Series 42U rack

Table 1 lists the inertia parameters for the rack and Plinth assembly shown in Figure 2.

Table 1. Inertia parameters for the HP 10000 Series 42U rack

Polarmoment

Inertia with respect to coordinate(Metric (English))

Inertia at center of gravity(Metric (English))

Ixx 220150.0 Tonne-mm2(752290.38 lbm-in2) 79584.362 Tonne-mm2(271953.45

lbm-in2)

Ixy -15548.153 Tonne-mm2 (-53130.711 lbm-in2) 130.184 Tonne-mm2(444.8611 lbm-in2)

Ixz -35420.85 Tonne-mm2 (-121039.13 lbm-in2) 7.8307109 Tonne-mm2(26.758885

lbm-in2)

Iyx -15548.153 Tonne-mm2 (--53130.711 lbm-in2) 130.184 Tonne-mm2(444.8611 lbm-in2)

Iyy 195230.35 Tonne-mm2 (667135.65 lbm-in2) 67006.025 Tonne-mm2(228971.11

lbm-in2)

Iyz -52931.505 Tonne-mm2 (-180876.05 lbm-in2) -913.58806 Tonne-mm2(-3121.8875

lbm-in2)

Izx -35420.85 Tonne-mm2 (-121039.13 lbm-in2) 7.8307109 Tonne-mm2(26.758885

lbm-in2)

X

Z

Y


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Polarmoment

Inertia with respect to coordinate(Metric (English))

Inertia at center of gravity(Metric (English))

Izy -52931.505 Tonne-mm2 (-180876.95 lbm-in2) -913.58806 Tonne-mm2(-3121.8875

lbm-in2)

Izz 58950.162 Tonne-mm2 (201442.84 lbm-in2) 25252.254 Tonne-mm2(86291.294

lbm-in2)

NOTES:Principle moments of inertia:I1= 25232.272 Tonn-mm2 (86223.011 lbm-in

2)

I2= 67024.66 Tonn-mm2 (86223.011 lbm-in2)

I3= 79585.71 Tonn-mm2 (271958.05 lbm-in2)

Longitudinal anchorage spacing = 484 mm (19.05 inches)Transverse anchorage spacing = 845 mm (33.27 inches)

Anchorage calculations

Anchorage requirements are determined by the longitudinal and transverse stability calculations for arack. These calculations are made using the minimum-design, vertical-live-load weight of the rack andthe lateral seismic force placed on it.

Vertical live load

The 1998 California building code, title 24, part 2 states: The minimum vertical design live loadshall be 20 pounds per cubic foot (311N/m3) or 20 pounds per square foot (958Pa = 0.1389462ilb/in2), whichever is less, but not less than the actual loads.

As applied to the HP 10000 Series 42U Rack (with an actual live load of 1500 pounds), thecalculation is as follows:

Cabinet volume: 1.0164 x 0.600 x 2.0565 = 1.2541 m3

Cabinet area: 1.0164 x 0.600 = 0.60984 m2(945.25 in2)

Calculated Vertical Loadvolume: 311 x 1.2541 = 390.025N (87.68 lb)

Calculated Vertical Loadarea: 0.1389462 x 945.25 = 131.34 lb

Since the actual live load is heavier, 1500 pounds will be used for the minimum-design, vertical-live-load parameter.

Lateral seismic force

The total design lateral seismic force (Fp) is determined by the following formula:

Fpmax = 4.0CaIpW

An alternative method of calculating lateral seismic force is with the formula of Fp = [(apCaIp)/Rp](1+ hx/hr)W (with the exception that Fp shall not be less than 0.7CaIpW and need not be more than4CaIpW). Table 2 lists the parameters and the values used for the formulas.

Table 2. Parameters and values for lateral seismic force formulas

Parameter Description Value Note

W Total weight of cabinet (includingcomponents) [1]

1750 [1]

Ip Importance factor 1 [2]

Ap Numerical coefficient (cabinets) 1 [2]

Ca Seismic coefficient 0.66 [3]


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Parameter Description Value Note

Rp Component Response Modification Factor(cabinets)

3 [2]

hx Element or component attachment elevationwith respect to grade:

Bottom floor2ndfloor or higher

01

[2][2]

hr Structure roof elevation with respect to gradeBottom floor2ndfloor or higher

01

[2][2]

NOTES:[1] In a dual system, California building code states that the frame will resist at least

25 percent of the load independently, leaving 75 percent of the load to beresisted by the anchorage.

[2] Value from California Building Code Title 24, part 2.[3] Value from California Building Code Title 24, part 2, Zone 4, Na= 1.5

Calculation for ground-level anchorage force

The calculations for the anchorage force of a rack installation at ground level are as follows:

Fp= .75{[(1.0*.66*1.0)/3](1 +0)1750} = 288.75 lb

Fpmin= .75{0.7(.66)(1.0)1750} = 606.38 lb

Fpmax= .75{4(.66)(1.0)1750} = 3465.0 lb

The stability calculations shown in Table 3 use the Fpminvalue of 606.38 pounds.

Table 3.Stability calculations for anchorage at ground level

Parameter Calculation Value

Overturning moment 39.59 x 606.38 24006.58 in-

lb0.9 Resistingmoment

0.9 x 11.93 x 1750 18789.75 in-lb

Longitudinal stability, left

Anchorage force (24006.58-18789.75)/19.05

273.85 lb

Overturning moment 39.59 x 606.38 24006.58 in-lb

0.9 Resistingmoment

0.9 x 11.69 x 1750 18411.75 in-lb

Longitudinal stability,right

Anchorage force (24006.58-18411.75)/19.05

293.69 lb

Overturning moment -- 24006.58 in-lb

0.9 Resistingmoment

0.9 x 17.52 x 1750 27594 in-lb

Transverse stability,forward

Anchorage force Resisting moment is greaterthan the overturningmoment

No anchorageneeded


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0.9 Resistingmoment

0.9 x 18.66 x 1750 29389 in-lb

Transverse stability,backward

Anchorage force Resisting moment is greaterthan the overturning

moment

No anchorageneeded

Axial load per anchor

Pmax: 293.69/2 = 146.85 lb

Shear load per anchor

Vmax: 606.38/4 = 151.60 lb


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Calcualtion for 2ndfloor and above anchorage force

The calculations for the anchorage force of a rack installation at levels above ground are as follows:

Fp= .75{[(1.0*.66*1.0)/3](1 +3)1750} = 1155 lb

Fpmin= .75{0.7(.66)(1.0)1750} = 606.38 lb

Fpmax= .75{4(.66)(1.0)1750} = 3465.0 lb

The stability calculations shown in Table 4 use the Fpvalue of 1155 pounds.

Table 4.Stability calculations for anchorage levels above ground


Overturning moment 39.59 x 1155 45726.45 in-lb

0.9 Resistingmoment

0.9 x 11.93 x 1750 18789.75 in-lb

Longitudinal stability, left

Anchorage force (45726-18789.75)/19.05 1414 lb

Overturning moment 39.59 x 1155 45726.45 in-lb

0.9 Resistingmoment

0.9 x 11.69 x 1750 18411.75 in-lb

Longitudinal stability,right

Anchorage force (45726-18411.75)/19.05 1433.84 lb


0.9 Resistingmoment

0.9 x 17.52 x 1750 27594 in-lb

Transverse stability,forward

Anchorage force (45726.45-27594)/33.27 545.01 lb


0.9 Resistingmoment

0.9 x 18.66 x 1750 29389 in-lb

Transverse stability,backward

Anchorage force (45726.45-29389.5)/33.27

491.04 lb

Axial load per anchor

Pmax: 1433.84/2 = 716.92 lb

Shear load per anchor

Vmax: 1155/4 = 288.75 lb


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Plinth anchoring scenarios

The Plinth kit is adaptable to racks mounted on either solid or raised flooring.

ot :For detailed information about anchoring, refer to the drawings in theappendix of this document.

Plinth anchored on raised flooring

In a facility where the Plinth will rest on raised flooring, the Plinth may be anchored using a system ofstruts and channel posts as shown in drawings S2 and S5 in the appendix.

Plinth anchored to solid floor

In a facility where the Plinth will rest on a solid floor, the Plinth may be anchored using four boltsscrewed into a solid floor as shown in drawings S1, S3, and S4 in the appendix.

Basic Plinth mounting procedureInstalling the Plinth requires the following basic steps:

1.Assemble the Plinth according to the installation guide included in the Plinth kit.2. Determine the method of anchoring the Plinth to the floor.3.Attach the four eyebolts to the top of the rack as necessary to help position or move the rack.4. Remove all leveling feet and castors as necessary from the bottom of the rack.5. Place the plinth into position on the floor and anchor using an appropriate method for the type of

floor in the facility.6. Place the rack onto Plinth, lining up the rack caster holes with the top holes of the Plinth.7. Install bolts through the aligned holes and tighten.

ot :The Plinth kit contains all hardware required for assembling the Plinth andmounting the rack onto the Plinth. Additional hardware may be requiredfor securing the Plinth to raised flooring or a solid floor.

Conclusion

For areas where ground movement and/or seismic activity is a concern, the HP Plinth Rack Option kit

offers a solution to the issue of equipment stability. Designed specifically for HP10000 Series Rackproducts, the HP Plinth Rack Option kit provides maximum stabilization for data centers implementingHP solutions.


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For more information

For more information about HP ProLiant servers and solutions, access the HP website at:

www.hp.com/servers/proliant

Call to Action

To help us better understand and meet your needs for ISS technology information, please sendcomments about this paper to: [email protected]
http://www.hp.com/servers/proliantmailto:[email protected]:[email protected]://www.hp.com/servers/proliant


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Appendix: Plinth kit drawings

The drawings in this appendix provide detailed information to help customers determine the hardware needed to securthe Plinth hardware and HP rack to a specific type of floor. Since reading details in these drawings is difficult on screewe recommend printing the drawings for easier reference.


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2004 Hewlett-Packard Development Company, L.P. The informationcontained herein is subject to change without notice. The only warranties forHP products and services are set forth in the express warranty statementsaccompanying such products and services. Nothing herein should be construedas constituting an additional warranty. HP shall not be liable for technical oreditorial errors or omissions contained herein.

TC041001BP, 10/2004

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