Attachment_1,_Maintenance_Specifications_for_Springs.pdf

SAXC 01-1028-E Final i

MAINTENANCE SPECIFICATIONS

FOR SPRINGS

SAXC 01-1028E

Prepared for

Department of the Air Force 721st Civil Engineer Squadron

Engineering Flight Cheyenne Mountain Air Force Station

July 2002

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TABLE OF CONTENTS

1.0 Introduction

2.0 Overview

2.1 Description of Spring Assemblies

2.2 Shock Isolation Protection Level of Spring Assemblies

2.3 Description of Dampers

3.0 Safety Precautions

4.0 Removal and Reinstallation of Springs

4.1 In-Place Spring Inspection

4.2 Spring Removal

4.3 Spring Reinstallation

5.0 Inspection and Testing, and Recoating of Springs

5.1 Inspection and Testing

5.2 Coating

5.2.1. Vinyl Paint

5.2.2. Powder Coating

6.0 Inspection and Maintenance of Dampers

6.1 In-Place Damper Inspection and Maintenance

6.1.1. Type I Damper Inspection

6.1.2. Type II and III Damper Inspection

LIST OF FIGURES

Figure 1. Base Plate, Top Plate, and Shipping Rod Details Figure 2. Turnbuckle Detail Figure 3. Spring Attributes Figure 4. Spring and Damper Protected Buildings in the CMC Figure 5. Typical Spring and Damper Layout Under Building 12108 Figure 6. Type I Damper Figure 7. Type II Damper Figure 8. Type III Damper

LIST OF TABLES

Table 1. Spring Properties Table 2. Spring Quantities and Locations in the CMC Table 3. Damper Quantities and Locations in the CMC

REFERENCES

APPENDIX A - FORMS

APPENDIX B - SPECIFICATIONS

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1.0 Introduction

The function of the ground shock isolation system in the CMC is to provide protection for personnel, buildings, and equipment from manmade or naturally occurring shock waves. The system consists of spring assemblies and two types of dampers. This scope of this document is limited to the removal, refurbishment, and reinstallation of the spring assemblies and dampers.

2.0 Overview

2.1 Description of Spring Assemblies

Each spring assembly located at a building foundation consists of a metal base plate anchored with four symmetrically-placed anchor bolts to the concrete below, and a top plate welded to the steel beam above. The helical compression spring is located between the two plates and held in place by a metal keeper ring welded to each plate. A black paint mark at the edge of the base plate identifies the quadrant toward which the lower end of the spring is pointing.

Figure 1 shows the base plate and shipping rod details.

Figure 2 shows a detail of a turnbuckle used to hold a spring in compression during removal and replacement and/or shipping.

Figures 3 shows a typical spring and its nominal attributes. Spring properties are listed in Table 1.

Figure 4 shows a plan of the CMC which indicates the location of each of the spring-protected buildings. Spring assemblies are arranged on each side along the longitudinal dimension at the base of each structure and at the base of equipment platforms. The installation pattern for each building consists of an equal number of right and left helix assemblies placed alternately in line and opposite each other. Consecutive springs are positioned so that the bottom end coils are rotated 90 degrees.

Spring quantities and locations are listed in Table 2. Figure 5 shows the spring and damper layout under building 12108, which is typical of spring-protected buildings.

2.2 Shock Isolation Protection Level of Spring Assemblies

The ground shock isolation system will limit the shock absorbed by buildings and equipment to suitable levels according to function. The springs included in the scope of this report are intended to protect all major structures from ground accelerations of more than 1g.

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Figure 1. Base Plate, Top Plate, and Shipping Rod Details

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Figure 2. Turnbuckle Detail

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Figure 3. Spring Attributes

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Table 1. Spring Properties

Physical Properties Tensile Strength, Min. 215,000 lb/in2 Tensile Yield (at 0.2% offset), Min. 180,000 lb/in2 Shear Yield 120,000 lb/in2 Solid Stress, Max. 115,000 lb/in2 Shear Modulus 11,500 lb/in2 Longitudinal Elongation (in 2 in.), Min. 10% Longitudinal Reduction of Area, Min. 35%

Stiffness Properties Load Rate, Vertical 2,600 lb/in Load Rate, Horizontal (Ends Fixed) equal to 0.44 of vertical load rate 1,144 lb/in

Chemical Properties Carbon 0.55-0.65% Manganese 0.70-1.00% Molybdenum 0.25-0.35% Chromium 0.60-1.00% Silicon 0.20-0.35% Phosphorous 0.35% Max.

Sulfur 0.35% Max.

Fabrication Data Free Height 47.4 in Solid Height 22.4 in Shipping Height 37.4 in Bar Diameter 3.0 in Bar Length 466.0 in Coil Inside Diameter 15.8 in Total Turns 8.2 Active Turns 6.7 Effective Active Turns 6.5

Material/Manufacturing Data Manufacturing Spec.: ASTM A125-65 Spring Material Spec.: ASTM A304-66, Grade 4161H Type of Ends: Ground Shot Peening Requirements 0.010 to 0.012 C Intensity, 98% Min. Coverage Hardness: 45.7 to 49.6 Rc

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Figure 4. Spring and Damper Protected Buildings in the CMC

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Table 2. Spring Quantities and Locations in the CMC

Location Spring Quantity

Building 1 176

Building 2 152

Building 3 186

Building 4 90

Building 5 36

Building 6 36

Building 7 36

Building 8 70

Building 9 74

Building 10 38

Building 11 112

Power Plant (12) 156

Cooling Tower Adit 2 (13) 44

Electrical Bay (14) 142

Chiller Building (15) 44

Air Handling Building (16) 22

Cooling Tower Adit 1 (17) 13

TOTAL 1,427

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Figure 5. Typical Spring and Damper Layout Under Building 1000

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Each spring is to be identified on a metal strip welded onto the steel beam immediately above the top plate. The numbering system is composed of four elements; for example, 1-2-R-1 identifies a spring as follows:

1 - Building 1 2 - Position 2 within the building (in accordance with the numbering system shown in Figure 5) R - Right-handed spring 1 - Previously mentioned paint mark (numbered clockwise beginning with the northwesternmost quadrant of the base plate).

A metal tag attached to each spring indicates the contract number under which the spring was purchased, the vendor’s name, the spring loading rate, the spring serial number, and the spring heat number.

2.3 Description of Dampers

The second element of the shock isolation system, the friction dampers, are of the multi-directional, coulomb type. There are three types of dampers:

Type I and Type III dampers have a constant response force of 4,800 lbs. (+10%) vertically and 2,100 lbs. (+10%) laterally.

Type II dampers have a constant response force of 2,100 lbs. (+10%) vertically and 1,000 lbs.

(+10%) laterally.

Each damper is located on a base plate attached to the concrete below with four anchor bolts. The concrete poured into the excavation is anchored to the floor by four rock bolts.

Each Type I damper consists of six cylinders and rods constructed with four cotter pins at each end and connected to the base plate and upper adjustment plate by clevis pins. The adjustment plate is welded to the steel beam supporting the building.

Type II and Type III dampers include a single cylinder connected to a top plate. The top plate is welded to the building and a horizontal slide plate that restricts lateral motion at the base of the cylinder.

Dampers are located at the corners of the buildings inside of the springs in the quantities and locations listed in Table 3.

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Table 3. Damper Quantities and Locations in the CMC

Location Damper Quantity

Type I Type II Type III

Building 1 16

Building 2 16

Building 3 16

Building 4 8

Building 5 4

Building 6 4

Building 7 4

Building 8 8

Building 9 8

Building 10 4

Building 11 8

Power Plant (12) 12

Cooling Tower Adit 2 (13) 4

Electrical Bay (14) 8 4

Chiller Building (15) 4

Air Handling Building (16) 4

Cooling Tower Adit 1 (17) 4

TOTAL 20 36 4

Each damper is identified with a metal strip in an identical location to the spring identification strips. The numbering system is composed of three elements; for example, 1-2-2 identifies a damper as follows:

1 - Building 1 2 - Position 1 within the building (numbered beginning with the damper nearest the

Number 1 spring be the Number 1 damper and continuing in the same direction as the springs)

2 - Type II damper The three types of dampers are shown in Figures 6, 7, and 8.

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Figure 6. Type I Damper

Figure 7. Type II Damper

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Figure 8. Type III Damper

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3.0 Safety Precautions

Personnel and equipment hazards that may be encountered during performance of the removal, refurbishing, and reinstallation of the springs and dampers are marked as shown below. These hazard notices, which apply to the springs and dampers, are placed throughout this volume. The warnings are not intended to replace any existing warning signs within the Cheyenne Mountain Complex, and should be used in conjunction with such signs and good working practices.

WARNING

INDICATES A HAZARDOUS CONDITION THAT

COULD RESULT IN INJURY OR DEATH

CAUTION

INDICATES A HAZARDOUS CONDITION THAT

COULD RESULT IN DAMAGE TO EQUIPMENT.

NOTE

INFORMATION, SPECIAL INSTRUCTIONS, AND REMINDERS

PRECEDING A SPECIFIC STEP OF AN OPERATION,

MAINTENANCE, OR TROUBLE-SHOOTING TASK.

Other hazard condition notes that apply to the entire complex are as follows:

WARNING

THE COOLING TOWER ADITS, CTA-1 AND CTA-2 ARE DESIGNATED “NO-LONE”

AREAS. DO NOT ENTER ANY COOLING TOWER OR EXHAUST AREA

UNACCOMPANIED. NOTIFY YOUR SUPERVISOR AND CALL THE CCC (EXTENSION

3575) PRIOR TO ENTERING THESE AREAS. HARD HATS MUST BE WORN IN ALL

INDUSTRIAL AREAS. OTHER “NO-LONE” AREAS INCLUDE THE INDUSTRIAL

RESERVOIR AREA, UNDERNEATH ALL BUILDINGS, AND ON TOP OF ALL BUILDINGS.

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4.0 Removal and Reinstallation of Springs

4.1 In-Place Spring Inspection

Before removing a spring, measure and tabulate the following parameters and information (which should be measured as a part of regular annual inspections) on FORM TO BE DEVELOPED (included in Appendix A):

PARAMETER TOLERANCE

Loaded Height (1g Spring) 35.4 to 37.4 inches Lateral Tilt 0.50 Inches Longitudinal Tilt 1.00 Inch

INFORMATION NOTE

Overall Condition Presence of corrosion or physical damage Environment Wet and damp or corrosive atmosphere, standing water

4.2 Spring Removal

Prepare the spring for removal by performing the following operations:

1. Cut the welds that attachs the top plate to the beam of the building.

2. Install turnbuckles and shipping rods and by incrementally tightening the turnbuckles compress the spring adequately to allow its removal.

3. Remove the four nuts from the anchor bolts that secure the base plate to the concrete.

4. Wrap the spring with protective material to avoid damage to the spring and coating during removal

5. Remove the compressed spring from its location.

NOTE: IMMEDIATELY AFTER REMOVING EACH SPRING AN IDENTICAL SPRING

MUST BE REINSTALLED IN ITS PLACE USING THE STEPS FOR SPRING

REINSTALLATION.

4.3 Spring Reinstallation

1. Move the new spring into its intended location. Be sure to orient the spring correctly.

NOTE: WHEN INITIALLY ASSEMBLED, THE SHIPPING RODS CONTAINING EACH

SPRING COMPRESS THE SPRING 10 INCHES; THE TOTAL LOADING IS

APPROXIMATELY 26,000 LBS. FOR THAT REASON, DO NOT BURN OFF

OR CUT THE SHIPPING RODS. THEY MUST BE RELEASED AS DESCRIBED

IN STEP 3 BELOW.

2. Replace the nuts on the anchor bolts that secure the base plate to the concrete.

3. In order to maintain equal stress in each of a spring assembly, the spring shall be released in small increments by loosening the turnbuckles equal amounts. Each increment of loosening shall be on all four rods of the spring being installed to avoid personal injury or damage to the spring or building. After the turnbuckles are fully loosened and the spring is bearing on the bottom beam of the building, the turnbuckles may be removed.

4. Weld the top plate to the bottom of the building beam.

5. Recoat base plate as necessary with appropriate coatings for type of paint or coating used on spring.

6. Record the parameters listed in Section 4.1 (In-Place Spring Inspection).

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5.0 Inspection and Testing, and Recoating of Springs

5.1 Inspection and Testing

After springs are removed, spring shall be cleaned by plastic media blasting to White Metal Blasting SSPC-SP5 (SSI-Sa3), or NACE #1. Baseplates may be cleaned by plastic media blasting or by using hand and power tools.

Randomly select thirty percent of the springs and test as follows:

1. Check and record the following information on the appropriate forms (included in Appendix A):

a. Perpendicularity

b. Uniformity of Pitch

c. Permanent set

d. Free height

e. Vertical spring rate

2. Test spring and base plates for defects by either magnetic particle inspection (wet or dry method), X-ray, or ultrasound.

3. Remove all defects and pitted areas by grinding only to extent that spring remains within specification.

4. Remove sharp edges that may damage subsequent coating from the ends of spring.

5. Grind exterior edge of keeper ring on end plates to be powder coated to a minimum 1/4” radius.

6. Stress relieve spring.

7. Compress spring to solid height six times with a load not exceeding 125% of the solid load of 65,000 lbs. at a 1.5 second frequency to achieve the greatest amount of material loading.

8. Perform final magnetic particle, X-ray, or ultrasound inspection of spring.

9. Shot peen springs according to the following standard:

Coverage 98% (Min.)

Arc Height 0.010C to 0.012C Shot Size S-460 Shot Grade SAE J-444A

10. Recheck and record items a-e in step 1 above and record the information on the appropriate forms (included in Appendix A)

11. Apply a thin film of petroleum based coating to protect the spring from corrosion if it will not be coated immediately.

5.2 Coating

Either of the two coating methods listed below may be used.

5.2.1. Epoxy Paint

Solvent clean spring, then paint with two layers of semi-gloss off-white paint as follows:

Epoxy Phenolic Paint 5.0 to 6.0 mils dry film thickness (DFT) Epoxy Phenolic Paint 5.0 to 6.0 mils dry film thickness (DFT)

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The total thickness of both coats shall be between 10.0 and 12.0 mils total average DFT.

See Appendix B for specification for epoxy phenolic paint for springs.

5.2.2. Powder Coating

Powder coating for springs shall be a Vinyl 11 powder coating applied in a fluidized powder bed.

Powder coating shall be Atofina Chemical Company Rilsan®, Morton International Powder Coatings Corvel 70000/75000, or equal.

To powder coat a spring, follow these steps:

1. Solvent clean spring in preparation for powder coating. If powder coating is to be done at a later time, coat the spring with water-soluble oil to prevent oxidation of the exposed metal.

2. Mask threaded holes in top and bottom plates.

3. Apply primer if required for powder coating used.

4. Apply powder coating to spring and end plates to a FINAL thickness of 7.50 mils

(min.) - 15.0 mils (max.).

NOTE: Spring must not be heated to a temperature higher than 700 degrees F.

during the powder coating process.

5. After reinstalling spring and end plates as described in Section 4.3 “Spring Reinstallation” any damage to the powder coating shall be repaired in place by using a flame sprayed ethylene methacrylic acid (E.M.A.A.) copolymer powder.

See Appendix B for manufacturer’s specification for Vinyl 11 powder coating and E.M.A.A. copolymer powder..

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6.0 Inspection and Maintenance of Dampers

6.1 In-Place Damper Inspection and Maintenance

The damper assemblies are designed and manufactured to require virtually no routine maintenance. All surfaces, per specification, are either inherently corrosion-resistant or treated to be so. All attaching fasteners are double locked and adjustments are double locked and location marked after testing by the manufacturer. During inspection and work on dampers, take care to not touch the horizontal slide plate surfaces or the ram with hard objects; damaging those surfaces may affect damper performance. Annually check each unit as follows:

6.1.1. Type I Damper Inspection

1. Remove fabric skirt (if installed).

2. Wipe all surfaces clean with a dry cloth.

3. Remove all damping cylinders by removing cotter pins and clevis pins.

4. Remove the bottom damper unit frame by unbolting from the foundation blocks.

5. Thoroughly clean and paint with one coat of an epoxy phenolic paint taking care to not allow paint to remain on the cylinder dampers. See Appendix B for paint specification.

6. Reinstall the bottom damper unit frame using new corrosion resistant nuts and the existing anchor bolts. Paint anchor bolts after bottom frame reinstallation.

7. Clean and paint the upper damper unit frame in place in the same manner.

8. Rebuild or obtain new hydraulic damping cylinders.

9. Install rebuilt or new damping cylinders, ensuring that all cotter pins and clevis pins are in place.

10. Check to ensure that all height adjustment locking nuts are tight.

11. Touch up nicks and scratches in place with the three coat system described above.

12. Restore fabric skirt to original position and repair tears or punctures.

6.1.2. Type II and III Damper Inspection

1. Remove fabric skirt (if installed).

2. Check for entry of debris, etc. and remove.

3. Wipe all surfaces clean with a dry cloth.

4. Thoroughly clean and paint with one coat of an epoxy phenolic paint taking care to not allow paint to remain on the cylinder dampers. See Appendix B for paint specification.

5. Apply LPS 3 corrosion inhibitor (LPS Research Labs; conforms to MIL-C-16173E

Grade 2 Class I) or equal lightly to all surfaces EXCEPT horizontal slide plate and ram.

6. Restore fabric skirt to original position and repair tears or punctures.

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REFERENCES

NORAD Cheyenne Mountain Complex Operation-Maintenance Manual Volumes 14 and 14A, Black and Veatch, 1983.

Structural Adequacy, Remediation, and Condition Study for CMC Buildings 11000 and 12108 (Electrical Bay). New Mexico Engineering Research Institute, University of New Mexico, October 1993.

WEBSITE REFERENCES

Atofina Chemicals Technical Polymer Website, http://www.atofinachemicals.com/techpol

Morton International Powder Coatings Website, http://www.mortonpowder.com

Dupont Company, http://ww.dupont.com/industrial-polymers http://www.atofinachemicals.com/techpol/rilsan-literature.cfm http://www.atofinachemicals.com/techpol/rilsan-literature.cfm

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APPENDIX A

INSPECTION FORMS

IN-PLACE SPRING INSPECTION FORM

DATE: _______ Building No. ________ Spring No._________ Recorded by: ________________ Tag Data _____________________________________________ Hand/Twist ________________ Environment _____________________________________________________________________ Spring Condition _________________________________________________________________ Top Plate Condition ______________________________________________________________ Base Plate Condition _____________________________________________________________

IN-PLACE PARAMETERS TOLERANCE

Loaded Height (1g Spring) _____________________ 35.4 to 37.4 inches Lateral Tilt _____________________ 0.50 Inches Longitudinal Tilt _____________________ 1.00 Inch

SPRING INSPECTION FORM

DATE: _______ Building No. ________ Spring No._________ Recorded by: ________________ Tag Data _____________________________________________ Hand/Twist ________________

FREE-STANDING PARAMETERS

Perpendicularity _______________ Free Height __________________ Uniformity of Pitch _______________ Vertical Spring Rate __________________ Permanent set _______________

REPAIR COMMENTS/TEST DATA:

APPENDIX B

SPECIFICATIONS AND MSDS

Blast Cleaning Specification Springs to be painted shall be blast cleaned according to Steel Structures Painting Council (SSPC) White Metal Blasting SSPC-SP5 (SSI-Sa3), or National Association of Corrosion Engineers (NACE) White Metal Blast Cleaning NACE 1.

The definition of that specification requires the removal of all visible rust, mill scale, paint and contaminants, leaving the metal uniformly white or gray in appearance. This specification is used where maximum performance of protective coatings is necessary due to exceptionally severe conditions such as constant immersion in water or liquid chemicals.

Three Coat Paint Specification for Dampers First Coat paint shall conform to Federal Specification TT-P-641, Type III, zinc-dust-zinc oxide-phenolic resin primer or MIL-P-12742B, phenolic primer, minimum dry film thickness of 1.5 mils.

Second Coat shall be the same as the first, tinted for contrast.

Third Coat shall conform to Federal Specification TT-E-522, enamel, phenolic, lusterless, minimum dry film thickness of 1.0 mil.