Attachment4-UFCSection11.pdf

UFC 3-260-01

17 NOVEMBER 2008

SECTION 11 TIEDOWNS, MOORING, AND GROUNDING POINTS

B11-1 TYPES OF EQUIPMENT

B11-1.1 Mooring and Grounding Point. A mooring and grounding point is a mooring casting with a grounding rod attached. Aircraft mooring and grounding points are used to secure parked aircraft and also serve as electrodes for grounding connectors for aircraft. Combined mooring and grounding points have previously been used by the Army but are not currently used as they do not meet mooring and grounding design loads required by TM 1-1500-250-23.

B11-1.2 Mooring Point. A mooring point is a mooring casting without a grounding rod attached, used to secure parked aircraft. Mooring points are used by the Army.

B11-1.3 Static Grounding Point. A static grounding point is a ground rod attached to a casting. The casting protects the ground rod but does not provide mooring capability.

Static grounding points are used by the Army in aprons and hangars.

B11-1.4 Static Grounding Tiedown. A static grounding tiedown is a 3-meter (10-foot) rod with a closed-eye bend. The static grounding tiedown is not intended to secure parked aircraft but may serve as an electrode connection for static grounding of aircraft.

Static grounding tiedowns are installed at many Air Force installations.

B11-1.5 Tiedown Mooring Eye. A tiedown mooring eye is a mooring casting with a grounding rod attached. They are similar to the mooring and grounding point discussed above. Tiedown mooring eyes are used by the Navy and Marine Corps.

B11-2 MOORING POINTS FOR ARMY FIXED- AND ROTARY-WING AIRCRAFT

B11-2.1 Type. A mooring point consists of a ductile iron casting, as shown in Figure B11-1. The mooring casting is an oval-shaped casting with a cross-rod to which mooring hooks are attached.

Figure B11-1. Army Mooring Point

152mm [6"]

51mm [2"] [3/8"]

51mm

[6.5"]

[3-1/2"] R

11mm [7/16"]

(2) 13mm [1/2"] DIA.

CORED HOLES

29mm

22mm [7/8"] DIA.

73mm [2-7/8"]

121mm [4-3/4"]

51mm [2"]

197mm [7-3/4"]

PLAN

SECTION

MOORING DEVICE TO BE CAST

IN DUCTILE IRON 80-55-06

OR EQUAL.

165mm

[1-1/8"]

89m m

9.5mm

[2"]

N.T.S.

B11-2.2 Design Load. Unless specifically waived in writing by the facility commander, all new construction of Army aircraft parking aprons will include aircraft mooring points designed for a 67,800-Newton (15,250-pound) load, as specified in TM 1- 1500-250-23 and applied at 19.15 degrees (19.15°) from the pavement surface, as illustrated in Figure B11-2.

Figure B11-2. Army Load Testing of Mooring Points

19.15°

[15,250 LB]

MOORING DEVICE

67,835 N

MOORING TESTS SHOULD BE ACCOMPLISHED USING A HYDRAULIC RAM OR

SIMILAR DEVICE AND AN APPROPRIATE REACTION (HEAVY VEHICLE, ETC.)

THAT IS CAPABLE OF APPLYING A TENSILE LOAD OF 71,172 N [16,000 LB]

THE LENGTH OF MOORING CHAIN AND CONNECTING SHACKLE SHOULD BE

SELECTED IN SUCH A WAY THAT AN ANGLE OF 19.15° FROM THE PAVEMENT

SURFACE (SEE ABOVE FIGURE) CAN BE MAINTAINED DURING LOAD TESTING.

APPROPRIATE SAFETY PRECAUTIONS SHOULD BE TAKEN AT ALL TIMES DURING

LOAD TESTING OPERATIONS.

TO PASS TEST REQUIREMENTS, MOORING POINTS SHALL NOT DEFORM

PERMANENTLY UNDER 71,172 N [16,000 LB] LOAD.

1.

2.

3.

4.

5.

NOTES

THE MOORING POINTS SHOULD BE LOADED IN 1,130 kg [2,500 LB]

INCREMENTS UP TO 44,482 N [10,000 LB] AND IN 4,448 N [1000 LB]

INCREMENTS UP TO 71,172 N [16,000 LB] WITH EACH LOAD INCREMENT

HELD FOR AT LEAST 60 SECONDS.

B11-2.3 Layout.

B11-2.3.1 Fixed-Wing Aprons. Mooring points should be located as recommended by the aircraft manufacturer or as required by the base.

B11-2.3.2 Rotary-Wing Aprons.

B11-2.3.2.1 Number of Moored Parking Spaces. Moored parking spaces will be provided for 100 percent of the authorized aircraft. The combined total of apron parking space and hangar parking space should provide sufficient parking for wind protection for all facilities’ authorized aircraft and typical transient aircraft. Additional parking spaces with mooring points may be added as necessary to ensure wind protection for all aircraft. The locations of these additional mooring points can be on pavements other than parking aprons. Prepared turf-surfaced areas are acceptable for rotary-wing aircraft mooring locations.

B11-2.3.2.2 Number of Mooring Points at Each Parking Space. Each rotary-wing aircraft parking space location will have six mooring points. Although some rotary-wing aircraft only require four mooring points, six will be installed to provide greater flexibility for the types of rotary-wing aircraft that can be moored at each parking space. The largest diameter rotor blade of the facilities’ assigned aircraft will be used for locating the mooring points within the parking space. The allowable spacing and layout of the six mooring points is illustrated in Figure B11-3. Parking space width and length dimensions are presented in Table 6-2 of Chapter 6.

Figure B11-3. Army Rotary-Wing Allowable Mooring Point Spacing

W

MOORING DEVICE (TYPICAL)

SEE FIGURE A12.1

1.

2.

3.

NOTES

LL

THE PREFERRED MOORING POINT SPACING FOR EACH AIRCRAFT PARKING

POSITION IS L =L = W = 6m [20.0']

IN NEW OR EXISTING RIGID PAVEMENT, THE MOORING POINTS WILL BE

AT LEAST 600mm [2'] AWAY FROM ANY PAVEMENT JOINT OR EDGE. TO MISS

THE PAVING JOINTS, THE SPACING OF THE MOORING POINTS MAY BE

VARIED AS FOLLOWS:

A. W, L AND L MAY VARY FROM 5 TO 6m [17 TO 20'].

B. W, L AND L NEED NOT BE EQUAL.

THE CONSTRUCTION TOLERANCE ON MOORING POINT LOCATION SHOULD

BE 50mm [±2"]

1 2

1 2

[2']STATIC GROUND

POINT

600mm

B11-2.3.2.3 Mooring Points on a Grid Pattern. A 6-meter by 6-meter [20-foot by 20-foot] mooring point grid pattern throughout the apron for mass aircraft parking aprons will not be authorized unless economically and operationally justified in writing by the installation commander. Figure B11-4 provides the recommended pavement joint and mooring point spacing should grid pattern mooring be utilized.

Figure B11-4. Army Rotary-Wing Mooring Points Layout

1.5m

1.

5m

6m [2

0'

6m [20'] TYPICAL

3m [10']

TYPICAL

3m [1

0'

T Y

P

IC

A L

TYPICAL MOORING

POINT

THIS IS THE RECOMMENDED JOINT SPACING FOR NEW CONCRETE PAVEMENT

WHERE MOORING DEVICES ARE JUSTIFIED AND AUTHORIZED THROUGHOUT

THE APRON. OTHER JOINT SPACINGS MAY BE USED AS LONG AS MOORING

DEVICES ARE SPACED AS SHOWN IN FIGURE B11-3.

NOTE

T Y

P

IC

A L

[5']

[5

B11-2.4 Installation

B11-2.4.1 Mooring Points for New Rigid Pavement Equal to or Greater Than 150 Millimeters (6 Inches) Thick. Mooring points for new rigid pavements will be provided by embedding the mooring devices in fresh Portland cement concrete (PCC).

The layout of points is shown in Figure B11-3 with mooring points at least 600 millimeters (2 feet) from the new pavement joints. This spacing will require close coordination between the parking plan and the jointing plan. Mooring points should be located a minimum of 600 millimeters (2 feet) from any pavement edge or joint and should provide proper cover for the reinforcing steel. Reinforcing bars should be placed around the mooring points as illustrated in Figure B11-5.

Figure B11-5. Slab Reinforcement for Army Mooring Point

1,000mm [3']

LONG. SEE NOTE.

MOORING DEVICE

(SEE FIGURE B11-1)

BARS

1,200mm [4'] LONG.

PLAN VIEW

THESE #6 REINFORCING BARS SHOULD BE PLACED 75mm [3"] FROM MOORING DEVICE AND 75mm [3"] BELOW PAVEMENT SURFACE.

THE ENDS OF REINFORCING BARS SHOULD BE PLACED 75mm [3"]

FROM PAVING JOINTS TO PROVIDE COVER.

1.

2.

NOTES

20mm [#6] BARS

20mm [#6]

B11-2.4.2 Mooring Points for Existing Rigid Pavement Equal to or Greater Than 150 Millimeters (6 Inches) Thick and in Uncracked Condition. The following method should be used to provide mooring points for existing rigid pavement in an uncracked condition. The pavement should have only a few slabs with random cracks and must not exhibit "D" cracking. Mooring points should be provided by core-drilling a 300-millimeter (12-inch) -diameter hole through the pavement and installing a mooring point as illustrated in Figure B11-6.

Figure B11-6. Mooring Point for Existing Rigid Pavement for Pavement Thickness Greater Than 150 Millimeters (6 Inches)

600mm [24"] MIN.

0m m [2

4" ] M

IN

[4

M

IN

MOORING DEVICE FOR

DETAILS SEE FIGURE B11-1

B B

300mm [12"] DIA. CORE HOLE

PLAN VIEW

EXISTING CONTRACTION

AND/OR CONSTRUCTION

JOINTS

SET TOP OF MOORING DEVICE

FLUSH WITH EXISTING PAVEMENT

SURFACE

CORE HOLE TO BE ROUGHENED

BY SAND BLASTING

50mm [2"] MIN.

[6"] OR

GREATER

CONCRETE WILL HAVE A MINIMUM

COMPRESSIVE STRENGTH 41.400 kPa [6000 psi], AND WILL BE PLACED IN AT LEAST 2

LIFTS. EACH LIFT WILL BE CONSOLIDATED

BY INTERNAL VIBRATION, ALLOW CONCRETE

SECTION B

EXISTING CONCRETE SHOULD HAVE

ONLY A FEW SLABS WITH CRACKS

IF THIS OPTION IS TO BE USED.

NOTE

TO "MUSHROOM" BELOW EXISTING SLAB.

m m

150 mm

[12"] DIA.

300 mm

B11-2.4.3 Mooring Points for Areas Not Covered Above. The following installation options should be used to provide mooring points for rotary-wing aircraft parked on the following pavements: existing rigid pavement less than 150 millimeters (6 inches) thick;

existing rigid pavement in a cracked or deteriorated condition; new or existing flexible pavement; turfed areas; and other areas where appropriate.

B11-2.4.3.1 Installation Option 1, Mooring Pad. This option is the preferred installation method and allows for placement of a new concrete pad with a minimum thickness of 200 millimeters (8 inches). The size of the pad should be a minimum of

7.3 meters (24 feet) wide by 13.4 meters (44 feet) long. The length and width may be increased to match the existing concrete joint pattern. The mooring pad, with six mooring points, is illustrated in Figure B11-7. The mooring devices should be installed as illustrated in Figure B11-1 and the concrete reinforced as illustrated in Figure B11-5.

Figure B11-7. Army Rotary-Wing Mooring Pad Detail

[2 0'

[2 4'

[2'] MIN.

6.1m [20'] 6.1m [20']

13.4m [44'] MIN.

0.6m

0.6m

MOORING POINT LOCATION (TYPICAL)

SEE FIGURE B11-1

PLAN VIEW

THIS MOORING PAD IS THE PREFERRED METHOD OF PROVIDING MOORING

POINTS IN GRASSED AREAS AND IN FLEXIBLE PAVEMENTS. FOR RIGID

PAVEMENT APPLICATIONS, THE SIZE OF THE PAD SHOULD BE INCREASED

TO MATCH THE EXISTING JOINT PATTERN.

THICKNESS OF THE PAD SHOULD BE DESIGNED TO CARRY THE EXPECTED

AIRCRAFT LOADS, BUT NOT LESS THAN 200mm [8"].

THE SLAB SHOULD BE DESIGNED AS A REINFORCED SLAB SO THAT

PAVEMENT JOINTING WILL NOT BE REQUIRED. IF JOINTED PAVEMENT IS

DESIRED, JOINT SPACING SHOULD BE ADJUSTED SO THAT MOORING

POINTS ARE A MINIMUM OF 0.6m [2'] FROM PAVEMENT JOINTS.

SEE FIGURE B11-6 FOR REINFORCING ADJACENT TO MOORING DEVICE.

TYPICAL PREFERRED SPACING BETWEEN MOORING DEVICES IS 6.1m [20']. SEE

FIGURE B11-3 FOR ALLOWABLE MOORING AND STATIC GROUND POINT SPACING.

1.

2.

3.

4.

5.

NOTES

PORTLAND CONCRETE PAD

M

IN

[2'] MIN.

[2'] MIN.

0.6m

6.

1m

7.

3m

N.T.S.

0.6m

[2'] MIN.

B11-2.4.3.2 Installation Option 2, Piers. This option allows the use of individual concrete piers for each mooring point, as shown in Figure B11-8. The diameter and length of the pier must be based on the strength of the soil, as presented in Table B11-1.

Figure B11-8. Army Mooring Point for Grassed Areas, Flexible Pavement, or Rigid Pavement - Thickness Less Than 150 millimeters (6 inches)

ASPHALT PAVEMENT, RIGID

PAVEMENT OR GRASSED

AREAS

MOORING DEVICE

(SEE FIGURE B11-1)

TIES

3 AT 150mm [6"]

TIES

3 AT 300mm [12"] m m m m [3

75mm [3"] CONCRETE

COVER (TYP.)

TIES AS

SHOWN

6-20mm [#6] BARS

VERTICAL

SEE NOTE 2

SECTION

A

CORE DRILL ASPHALT PAVEMENT. FOR PIER LENGTH

AND DIAMETER, SEE TABLE B11-1

SPIRAL REINFORCEMENT EQUIVALENT TO THE 13mm [#4]

TIES MAY BE USED.

SEE FIGURE B11-3 FOR ALLOWABLE MOORING AND STATIC

1.

2.

3.

NOTES

16mm [NO. 4] COPPER

CONDUCTOR

A A

[1

13mm [#4]

ELEVATION

N.T.S.

GROUND POINT SPACING

Table B11-1. Army Pier Length and Depths for Tiedowns

Cohesive Soils

Pier Diameter Pier Length

Unconfined Compressive Strength

(qu in kg/m2 [lb/ft2) m ft m ft qu < 5,000 kg/m2

(qu < 1,000 lb/ft2)

600 mm 2.0 ft 1,800 mm 6.0 ft

5,000< qu <19,500 kg/m2

(1,000< qu <4,000 lb/ft2)

500 mm 1.5 ft 1,800 mm 6.0 ft qu >18,500 kg/m2

(qu >4,000 lb/ft2)

500 mm 1.5 ft 1,200 mm 4.0 ft

Cohesionless Soils

Pier Diameter Pier Length

Friction Angle ∅ in Degrees m ft m ft

∅ < 20° 600 mm 2.0 ft 2,100 mm 7.0 ft

20° ≤ ∅ ≤ 30° 600 mm 2.0 ft 1,800 mm 6.0 ft

∅ > 30° 500 mm 1.5 ft 1,800 mm 6.0 ft

B11-3 EXISTING MOORING POINTS FOR ARMY. Existing mooring points will be tested for structural integrity and strength as detailed in Figure B11-2. If the existing mooring fails to meet the structural requirements listed herein, replacement of the mooring structure is required. If the existing mooring point has an attached ground rod, its electrical resistance value must be measured. If it fails to meet resistivity requirements, a new static ground rod is required.

B11-3.1 Evaluation of Existing Mooring Points for Structural Adequacy

B11-3.1.1 Adequate Mooring Points. Existing 19-millimeter (0.75-inch) -diameter bimetallic, copper-covered steel rods, 1,800 millimeters (6 feet) long are considered adequate for immediate aircraft protection, provided the following conditions are met:

The existing rods are installed in rigid pavement.

The existing rods do not show signs of deformation or corrosion.

The existing rods are inspected for deformation and corrosion at least once a year and after each storm event with winds greater than 90 kilometers per hour (50 knots).

B11-3.1.2 Inadequate Mooring Points. At Army facilities, any existing rods that exhibit deformation or corrosion will be considered inadequate and require replacement.

All existing 19-millimeter (0.75-inch) -diameter, 1,800-millimeter (6-foot) -long rods in flexible (asphalt) pavement, including those with a Portland cement concrete (PCC) block at the surface, require replacement.

B11-3.2 Evaluation of Existing Mooring Points for Resistance. The maximum resistance measured, in accordance with IEEE Standard 142, of existing grounding points, will not exceed 10,000 ohms under normally dry conditions. If this resistance cannot be obtained, an alternative grounding system will be designed.

B11-4 STATIC GROUNDING POINTS FOR ARMY FIXED- AND ROTARY-WING

FACILITIES

B11-4.1 Type. A static grounding point for Army facilities is a 3-meter (10-foot) rod with a closed eye (see Air Force Static Ground, Figure B11-12) except when installed in a hangar. Inside hangars, the static ground point consists of a copperweld rod attached to a bronze casting with a threaded connection, as shown in Figure B11-9.

Figure B11-9. Army Grounding Point Inside Aircraft Hangars

70mm [2-3/4"] DIA.

73mm [2-7/8"]

19mm [3/4"]

2,400mm [8']

FINISHED APRON

4mm [NO. 10] BRASS BALL CHAIN

19mm [3/4"] N.C. THREAD

19mm [3/4"] COPPER-WELD GROUND

ROD

CAST BRONZE COVER

FRICTION FIT

CAST BRONZE

HOUSING

BRASS PIN 2

B11-4.2 Layout

B11-4.2.1 Fixed-Wing Layout. Static grounding points for fixed-wing aircraft will be located on the parking apron as recommended by the aircraft manufacturer or as required by the facility. Typically, one static grounding point is provided for every two parking spaces, and is located between the parking spaces.

B11-4.2.2 Rotary-Wing Layout. One static grounding point will be provided at each rotary-wing aircraft parking space, as shown in Figure B11-10.

B11-4.3 Installation. Static grounding points can be installed in new concrete or asphalt. New grounding points placed in turf areas will be constructed in a 12,000-square-millimeter (18-square-inch) concrete pad flush with existing ground. Static grounding points for turf areas are shown in Figure B11-11.

B11-4.4 Grounding Requirements. In accordance with IEEE Standard 81, the maximum resistance measured of new grounding points will not exceed 10,000 ohms under normal dry conditions. If this resistance cannot be obtained, an alternative grounding system will be designed.

Figure B11-10. Mooring and Ground Point Layout for Rotary-Wing Parking Space

6m

6m [20'] 6m [20']

STATIC GROUNDING

POINT

MOORING POINT-SIX

LOCATIONS TYPICAL

0.6m [2']

TIEDOWN

CABLE

Figure B11-11. Army Grounding Point for Turf Areas

450mm [18"]

CONCRETE

PAD

ARMY STATIC

GROUNDING POINT

EXISTING

GROUND

PAD CONSTRUCTED FLUSH

WITH EXISTING GROUND

150mm [6"] CONCRETE MARKER PAD

OVER EXISTING SOIL

GROUND ROD WITH SCREW

3,000mm [10'] COPPER

TYPE BOTTOM ANCHOR

B11-5 AIR FORCE TIEDOWNS AND STATIC GROUNDS

B11-5.1 General. For the Air Force, tiedowns will be constructed in accordance with Figures B11-14 and B11-15 and may be used as a static ground provided they meet the requirements given in paragraph B11-5.4. For maximum flexibility, they may be installed in 4.6-meter (15-foot), 6.1-meter (20-foot), or 9.1-meter (30-foot) grids, or offset grids. At minimum, place tiedowns as indicated in aircraft Technical Orders or Facility Requirements Documents. Ideally, tiedowns will be centered in slabs, but, at minimum, shall not be located less than 914 millimeters (3 feet) from any joint.

B11-5.1.1 If tiedowns are intended to also be used as static grounds, soil conditions may require that a ground rod be installed. When a ground rod is included, bond it to the tiedown bar.

B11-5.1.2 Static grounding points will be installed using a minimum 3-meter (10-foot) rod with a closed eye. The 3-meter (10-foot) rod will have a diameter of not less than 19 millimeters (0.75 inch) and the top will be a closed forged eye or a shepherd's hook bend with clamped sleeve, having an inside diameter of not less than 40 millimeters (1.5 inches) (see Figure B11-12). The rod may be copper, copper-clad steel, galvanized steel, or copper-zinc-silicone alloy. The Air Force static ground is used only as a static ground, not an electrical ground, and is not designed to withstand the uplift forces imposed for mooring aircraft. On aprons, stencil the pavement near each static ground with the legend "Static Ground Only" in 102-millimeter (4- inch) block letters. Black lettering on a yellow background that extends a minimum of 51 mm (2 in) beyond the outermost edges of the letters is recommended.

B11-5.1.3 Inside hangars, Air Force activities may use the Army static ground fixture shown in Figure B11-9. All static ground fixtures inside hangars must be connected to the building ground and all grounds must be bonded.

B11-5.2 Layout. Static grounds and tiedowns will be configured and spaced in accordance with the requirements of the mission aircraft and will vary from aircraft to aircraft. An example of a multiple fixed-wing aircraft tiedown layout is shown in Figure B11-13.

Figure B11-12. Air Force Static Ground

19mm

19mm

5m m m m m m

[4

/2

A P

P R

O X

DETAIL OF EYE AND

SLEEVE ASSEMBLY 127mm [5"] DIA. MIN.

PAVEMENT

150mm [6"] MAX.

5m m

A A

B

B

APPROX. 80mm [3-1/4"] R.

ANCHOR

ANCHOR

EDGES ROUNDED

SECTION A

SECTION

B

DETAIL OF PAVEMENT RECESS

FOR CONCRETE

[3/4"] R

[3/4"] R

[1

[1

/2

[3

38 mm [1.5"]

THREADED OR

WELDED SCREW

ANCHOR FOR

FLEXIBLE PAVEMENT

SHEPHERDS HOOK

OR FORGED EYE

19mm [3/4"] MIN DIAMETER x 3,000mm [10'] COPPER, COPPER

CLAD STEEL, GALVANIZED

STEEL, OR

COPPER-ZINC-SILICONE ALLOY

COPPER COMPRESSION

SLEEVE FOR SHEPHERDS

HOOK STYLE ROD ENDS

NOTES

1. STATIC TIEDOWN GROUNDS ARE NOT INTENDED

AS AIRCRAFT TIEDOWNS OR THRUST ANCHORS.

2. THESE WILL BE USED AS EXTERIOR STATIC

GROUND POINTS FOR ARMY ROTARY WING

AIRCRAFT.

Figure B11-13. Example of Air Force Multiple Tiedown Layout for Fixed-Wing Aircraft

6m [20']

18m [60']

6m [20']

17m [56']

9m

3m [10']

B-1B BLAST DEFLECTOR

B-1B TIEDOWN

LOCATION

THIS IS AN EXAMPLE FOR ONE AIRCRAFT (B-1B).

FOR SPECIFIC AIRCRAFT DIMENSIONS REFERENCE

THE AIRCRAFT TECHNICAL ORDER (T.O.)

(AVAILABLE FROM MAINTENANCE ASSISTANCE

PROGRAM OFFICE).

[30']

C OF PARKING SPOTL C OF PARKING SPOTL

NOTE:

B11-5.3 Installation

B11-5.3.1 Static Grounds in Rigid Pavement. Where static grounds are to be installed in rigid pavement, the rods may be installed without bottom anchors. Static grounds should be offset a minimum of 600 millimeters (2 feet) from any pavement edge, joint, or tiedown point.

B11-5.3.2 Static Grounds in Flexible Pavements. Where flexible pavement is to be constructed, static grounding rods will be equipped with a screw-type bottom end having a wing diameter of not less than 127 millimeters (5 inches), as shown in Figure B11-12. The helical anchor may be welded to the rod or the rod may be threaded to permit attachment to the bottom anchor.

B11-5.3.3 Pavement Recess Design. The top of the static ground will be set at pavement grade or not more than 6 millimeters (0.25 inch) below grade. A smooth, rounded-edge recess 75 millimeters (3 inches) wide and not more than 150 millimeters (6 inches) long will be provided in the pavement around the eye for accessibility and attachment of grounding cables. This is shown in Figure B11-12.

Figure B11-14. Air Force Aircraft Tiedown, Profile

127mm [5"]

NOTES:

1. PLACE TIE DOWNS AS INDICATED IN AIRCRAFT TECHNICAL ORDER OR FACILITY REQUIREMENTS

DOCUMENT. IF THE TIEDOWN IS INTENDED TO ALSO BE USED AS A STATIC GROUND, SOIL

CONDITIONS MAY REQUIRE THAT A GROUND ROD BE INSTALLED. WHEN A GROUND ROD IS

INCLUDED, BOND IT TO THE TIEDOWN BAR.

2. MINIMUM DISTANCE FROM TIEDOWN CENTER POINT TO AN UNDOWELED JOINT IS 914 mm (3').

WHEN TIE DOWNS OCCUR 914mm [3 '] FROM A SINGLE JOINT, ORIENT BAR PARALLEL WITH THE JOINT. IF CENTER POINT OCCURS 914mm (3') FROM ADJACENT JOINTS, ORIENT BAR PARALLEL

WITH EITHER JOINT.

3. BAR WILL BE 32mm [1.25"] AISI 4130.

4. MINIMUM SLAB THICKNESS IS 254mm [10"].

5. PIER DIMENSIONS FOR ASPHALT PAVEMENTS MUST BE DESIGNED TO ACCOMMODATE

ANTICIPATED UPLIFT FORCES. FOR 17,100 kg (37,700 LBS) MINIMUM PIER DIMENSIONS ARE 1.83m x 1.83m x 2.13m (6' x 6' x 7').

6. FOR INSTALLATION IN PREEXISTING SLABS, INSTALL 1" Ø x 16" DOWEL RODS CENTERED AT HALF

SLAB DEPTH , ALL FOUR SIDES AS SHOWN IN THE PLAN VIEW. MINIMUM ANCHOR BLOCK

DIMENSIONS IN THIS CASE ARE 254mm [10"] x 1,067mm [42"] x 1,067mm [42"].

76mm [3"] R

146mm [5.75"]

914.4mm [36"]

254mm [10"] MINIMUM

92.25mm [3.75"]

178mm [7"] 127mm [5"] 152mm [6"]

#5 REBAR, FOUR

EACH WAY, TYP

114mm [4.5"]

DOWELS REQUIRED FOR

INSTALLATION IN PREEXISTING SLABS,

SEE NOTE 6

406mm [16"]

DOWEL

PRE-EXISTING

SLABS

Figure B11-15. Air Force Aircraft Tiedown, Plan

25mm [1"]

DOWELS

1,067mm [42"]

1,067mm [42"] 76mm [3"] MIN

305mm [12"] MIN

152mm 6"]

203 mm [8"]

203 mm [8"]

1m (3') MIN TO JOINT

1m (3') MIN TO JOINT

B11-5.4 Grounding Requirements. The maximum resistance of new static grounds, measured in accordance with IEEE Standard 81, should not exceed 10,000 ohms under normal dry conditions. If this resistance cannot be achieved, an alternative grounding system should be considered. Tiedowns that meet the above requirements may be used as static grounds.

B11-6 TIEDOWN MOORING EYES FOR NAVY AND MARINE CORPS.

Requirements, layout, and installation details for Navy and Marine Corps tiedown mooring eyes are found in Figure B11-16. Requirements, layout, and installation details for Navy and Marine Corps grounding arrangements are found in MIL-HDBK-274.

Figure B11-16. Navy and Marine Corps Mooring Eye/Tiedown Details

H/3

TIEDOWN/MOORING EYE-TYPE A

BAR Ø

NOT TO SCALE

DEPRESSION

HEMISPHERICAL

TROWELED

ADJUST TO SATISFY

DIMENSION "H"

CONTRACTOR TO

H

NOT TO SCALE

DEPRESSION

HEMISPHERICAL

TROWELED

LC

3" R

TIEDOWN/MOORING EYE (RETROFIT) DETAIL

610mm [2'-0"]

[5" TO 6"]

H

2. WHEN REBAR FOR EYE OCCURS WITHIN 304mm (1') OF JOINT,

1. PLACE MOORING EYES AS INDICATED ON PLANS.

ORIENT REBAR PARALLEL TO JOINT.

NOTES

BAR SIZES

127 to 152mm

25.4mm [1"] R

76.2mm [3"] R

25.4mm [1"] R

63.5mm +/- 6mm [2.5" +/- 1/4"]

H <254mm

[<10"] 254 TO 305mm

[10" TO 12"]

330 TO 406mm

[13" TO 16"]

BAR Ø

19mm [0.75"]

25.4mm [1"]

31.75 [1.25"]

25.4mm [1"] R

305mm [12"] CORE

[5" TO 6"]

127 to 152mm

63.5mm +/- 6mm [2.5" +/- 1/4"]

EXISTING

CONCRETE

102mm x 254mm x 19mm [4" x 10" x 3/4"]

PLATE (SNUG FIT WITH BAR)

PLAIN BAR ASTM A572 WITH HEAVY HEX NUTS

25mm [1"] DIA. BAR FOR PAVEMENTS < 254mm

[10"] THICK

32mm [1.25"] DIA. BAR FOR PAVEMENTS > 254mm

[10"] THICK

H

76mm[3"]

76mm [3"]

NOTES

1. PLACE MOORING EYES AS INDICATED ON PLANS.

2. DO NOT PLACE MOORING EYE WITHIN 1M [3'] OF ANY CRACK OR JOINT.

3. THEORETICAL ULTIMATE PULLOUT CAPACITY FOR 25mm [1"] BAR AND PAVEMENT < 254mm [10"] IS 111 ,205

NEWTONS [25,000 LBS].

4. THEORETICAL ULTIMATE PULLOUT CAPACITY FOR 32mm [1.25"] BAR AND PAVEMENT > 254mm [10"] IS 200,170

NEWTONS [45,000 LBS].

SEQUENCE:

1. CORE PAVEMENT.

2. EXTEND SHAFT TO A MINIMUM DEPTH AND 76mm [3"] MINIMUM UNDERCUT SHOWN.

3. MAINTAIN SHAFT TILL PCC PLACEMENT.

4. PLACE BAR ASSEMBLY AND NEW CONCRETE (4,000 PSI MIN).

3. BAR SHALL BE SMOOTH (PLAIN ASTM A615, GRADE60, HOT-DIPPED

GALVANIZED IN ACCORDANCE WITH ASTM A123) UNLESS

OTHERWISE NOTED.

472mm DIA. SHAFT

76mm [3"] MIN. AT PERIMETER

COAT WITH EPOXY, ASTM C-881, TYPE V,

GRADE AS APPROVED, PRIOR TO NEW

CONCRETE PLACEMENT

4. IF DEFORMED BAR IS TO BE USED, BARBEND R = 127 mm [5"].

4-13 OBSTRUCTIONS AND AIRFIELD AIRSPACE CRITERIA.