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8/19/2019 Norma AREMA Para Ensayo a Flexion

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Concrete Ties

© 2001, American Railway Engineering and Maintenance-of-Way Association

AREMA Manual for Railway Engineering 30-4-27

c. The tie block and each of four ties submitted for testing shall be carefully measured and examined to

determine their compliance with the requirements of Section 4.2, Material and Section 4.3, Tie

Dimensions, Configuration and Weight. Upon satisfactory completion of this examination, the tie block

and two ties, which shall be known and identified as Tie “1” and “2”, shall be subjected to performance

tests specified in Article 4.9.1.4, Article 4.9.1.5, Article 4.9.1.6, Article 4.9.1.7, Article 4.9.1.8,

Article 4.9.1.9, Article 4.9.1.10, Article 4.9.1.11, Article 4.9.1.12, Article 4.9.1.13, and Article 4.9.1.14.

The remaining two ties, which will be known and identified as Ties “3” and “4”, will be retained by the

engineer for further test use and as a control for dimensional tolerances and surface appearance of ties

subsequently manufactured.

4.9.1.1 Sequence of Design Tests (Tie “1”)

The sequence of design performance tests using Tie “1” shall be as follows:

a. Rail Seat Vertical Load Test (described in Article 4.9.1.4). Shall be performed on one rail seat,

hereinafter designated rail seat A.

b. Center Negative Bending Moment Test (described in Article 4.9.1.6).

c. Center Positive Bending Moment Test (described in Article 4.9.1.7).

d. Rail Seat Vertical Load Test (described in Article 4.9.1.4). Shall be performed on the other rail seat,

hereinafter designated rail seat B.

e. Rail Seat Repeated Load Test (described in Article 4.9.1.5). Shall be performed on rail seat B.

f. Bond Development, Tendon Anchorage, and Ultimate Load Test (described in Article 4.9.1.8). Shall be

performed on rail seat A.

4.9.1.2 Sequence of Design Tests (Tie “2”)

The sequence of design performance tests using Tie “2” shall be as follows:

a. Fastening Insert Test (described in Article 4.9.1.9). Shall be performed on all inserts.

b. Fastening Uplift Test (described in Article 4.9.1.10a and b). Shall be performed on one rail seat.

c. Electrical Resistance and Impedance Test (described in Article 4.9.1.14).

4.9.1.3 Sequence of Design Tests (Tie Block)

The sequence of design performance tests using the tie block shall be as follows:

a. Tie Pad Test1 (described in Article 4.9.1.15).

b. Fastening Uplift Test Part A (described in Article 4.9.1.10).

c. Fastening Longitudinal Restraint test (described in Article 4.9.1.12).

d. Fastening Repeated load Test (described in Article 4.9.1.11).

e. Fastening Longitudinal Restraint Test (described in Article 4.9.1.12).

f. Fastening Uplift Test Part A (described in Article 4.9.1.10).

1 Test shall be conducted on three pads. The two pads providing highest and lowest spring rate values shall be discarded and remaining

pad shall be used for tests Article 4.9.1.3b through h.


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30-4-28 AREMA Manual for Railway Engineering

g. Fastening Lateral Restraint Test (described in Article 4.9.1.13).

h. Tie Pad Test (described in Article 4.9.1.15).

4.9.1.4 Rail Seat Vertical Load Test

With the tie supported and loaded as shown in Figure 30-4-7, a load increasing at a rate not greater than 5 kips(22 kN) per minute shall be applied until the load (P) required to produce the specified rail seat negative

moment from Section 4.4, Flexural Strength of Prestressed Monoblock Ties, Table 30-4-3 is obtained. This load

shall be held for not less than 3 minutes, during which time an inspection shall be made to determine if

structural cracking occurs. In like manner, the tie shall be supported and loaded as shown in Figure 30-4-8 to

produce the rail seat positive moment from Article 4.4.1, Table 30-4-3. An illuminated 5-power magnifying

glass may be used to locate cracks. If structural cracking does not occur, the requirements of each portion of

this test will have been met. Other material may be substituted for the rubber supports shown, by agreement

with the Engineer.

4.9.1.5 Rail Seat Repeated-Load Test

a. Following the vertical load test for positive moment on rail seat B, the load shall be increased at rate of at

least 5 kips (22 kN) per minute until the tie is cracked from its bottom surface up to the level of the lowerlayer of reinforcement.

b. After removal of the static rail seat load necessary to produce cracking, and substitution of ¹⁄₄ inch (6.35

mm) -thick plywood strips for those in Figure 30-4-8, the tie shall be subjected to 3 million cycles of

repeated loading with each cycle varying uniformly from 4 kips (17.8 kN) to the value of 1.1P. The

repeated loading shall not exceed 600 cycles per minute. If, after the application of 3 million cycles, the

tie can support the rail seat load (1.1P), the requirements of this test will have been met.

Figure 30-4-7. Rail Seat Negative Moment Test

M = NEGATIVE MOMENT AT THE RAIL SEAT AS

REQUIRED IN ARTICLE 4.4.1 OR ARTICLE 4.5.1


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4.9.1.6 Center Negative Bending Moment Test

With the tie supported and loaded as shown in Figure 30-4-9 a load increasing at a rate not grater than 5 kips

(22kN) per minute shall be applied until the load required to produce the specified negative center design

moment from Table 30-4-3 is obtained. The load shall be held for not less than 3 minutes, during which time an

inspection shall be made to determine if structural cracking occurs. An illuminated, 5-power magnifying glass

may be used to locate cracks. If structural cracking does not occur the requirements of this test will have been

met.

4.9.1.7 Center Positive Bending Moment Test

With the tie supported and loaded as shown in Figure 30-4-10, a load increasing at a rate not greater than 5

kips (22 kN) per minute shall be applied until the load required to produce the specified positive center design

moment from Table 30-4-3 is obtained. The load shall be held for not less than 3 minutes during which time an

inspection shall be made to determine if structural cracking occurs. An illuminated, 5-power magnifying glass

may be used to locate cracks. If structural cracking does not occur, the requirements of this test will have beenmet.

4.9.1.8 Bond Development, Tendon Anchorage, and Ultimate Load Test

a. Pretensioned concrete ties shall be tested for bond development, and ultimate strength as specified

below:

Figure 30-4-8. Rail Seat Positive Moment Test

M = POSITIVE MOMENT AT THE RAIL SEAT AS REQUIRED IN ARTICLE 4.4.1 FOR

PRESTRESSED MONOBLOCK TIES OR ARTICLE 4.5.1 FOR TWO BLOCK TIES


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(1) With the tie supported and loaded at rail seat A as shown in Figure 30-4-8, a load increasing at a rate

not greater than 5 kips (22 kN) per minute shall be applied until a total load of 1.5P is obtained (the

load P shall be as determined in “Rail Seat Vertical Load Test” for positive moment).

(2) If there is no more than 0.001 inch (0.025 mm) tendon slippage determined by an extensometer

reading to ¹⁄₁₀,₀₀₀ of an inch (¹⁄₄₀₀ mm), the requirements of this test will have been met. The

measurement shall be made on the outermost tendons of the lower layer. The load shall then be

increased until ultimate failure occurs and the maximum load obtained shall be recorded.

b. Post-tensioned concrete ties shall be tested for tendon anchorage and ultimate strength as specified

below:

With the tie supported and loaded as shown in Figure 30-4-8, a load increasing at a rate not greater than

5 kips (22 kN) per minute shall be applied until a total load equal to 1.5P is obtained. If the tie can

support this load for a period of 5 minutes, the requirements of this test will have been met. The load

shall then be increased until ultimate failure of the tie occurs, and the maximum load obtained shall be

recorded.

4.9.1.9 Fastening Insert Test

Fastening inserts shall be subjected to a pull-out test and a torque test as follows:

a. The pull-out test shall performed on each insert as shown on Figure 30-4-11. An axial load of 12 kips

(53.4 kN) shall be applied to each insert separately and held for not less than 3 minutes, during which

M = NEGATIVE MOMENT AT THE CENTER OF THE TIE AS REQUIRED IN ARTICLE 4.4.1

Figure 30-4-9. Tie Center Negative Moment Test


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time an inspection shall be made to determine if there is any slippage of the insert or any cracking of the

concrete.

NOTE: Mortar cracking in the vicinity of the insert is not a cause for failure. If failures occur, then the

requirements of this test will not have been met. Inability of the insert itself to resist the 12

kips (53.4 kN) load without permanent deformation shall also constitute failure of this test.

b. Following successful completion of the insert pull-out test, the torque test shall be performed on each

insert. A torque of 250 ft-lbarema (339 N•m) shall be applied about the vertical axis of the insert by

means of a calibrated torque wrench and a suitable attachment to the insert. The torque shall be held for

not less than 3 minutes. Ability of the insert to resist this torque without rotation, cracking of the

concrete, or permanent deformation shall constitute passage of this test.

4.9.1.10 Fastening Uplift Test

a. An 18 to 20 inches (460 mm - 510 mm) piece of the proper section of rail shall be secured to one rail seat

using a complete rail fastening assembly, including pads, bolts, clips and associated hardware, as

recommended by the manufacturer of the rail fastening system. In accordance with the loading diagram

in Figure 30-4-12, an incremental load shall be applied to the rail. The load P (measured load plus

unsupported tie weight plus frame weight) at which separation of the rail from pad or pad from rail seat

occurs (whichever occurs first) shall be recorded.1

1”P” shall not exceed 10 kips (44.5 kN).

M = POSITIVE MOMENT AT THE CENTER OF THE TIE AS REQUIRED IN ARTICLE 4.4.1

Figure 30-4-10. Tie Center Positive Moment Test


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b. The load shall then be completely released. A load of 1.5P not to exceed 10 kips (44.5 kN) shall then be

applied. The inserts shall not pull out or loosen in the concrete and no component of fastening system

shall fracture nor shall the rail be released.

4.9.1.11 Fastening Repeated-Load Test

a. An 18 to 20 inches (460 mm - 510 mm) section of new rail from which loose mill scale has been removed

by wiping with a cloth shall be secured to the rail seat in the block using a complete rail fastening

assembly. In accordance with the loading diagram in Figure 30-4-12 determine the load P that will justcause separation of the rail from the rail seat pad or the pad from the rail seat whichever occurs first. 1

This load may be determined during the Fastening Uplift Test described in Article 4.9.1.10 in which case

a new set of fastening clips shall be used for the repeated load test.

b. An 18 to 20 inches (460 mm - 510 mm) section of new rail from which loose mill scale has been removed

by wiping with a cloth shall be secured to the rail seat in the tie block using a complete rail fastening

assembly. In accordance with the loading diagram in Figure 30-4-13, alternating downward and upward

loads shall be applied at an angle of 20 degrees to the vertical axis of the rail at a rate not exceed 300

cycles per minute for 3 million cycles. The rail shall be free to rotate under the applied loads. One cycle

shall consist of both a downward and an upward load. The magnitude of the upward load shall be 0.6P

where P is the load determined in paragraph a . If springs are used to generate the upward load thedownward load shall be 30 kips (133.5 kN) plus 0.6P. If a double-acting hydraulic ram is used to generate

both the upward and the downward load, the downward load shall be 30 kips (133.5 kN).

c. This repeated load test may generate heat in elastomeric rail seat pads. Heat build-up in such pads must

not be allowed to exceed 140 degrees F (71 degrees C). Heat build-up can be controlled by reducing the

rate of load application or by providing periods of rest to allow cooling of the pad to take place.

d. Rupture failure of any component of the fastening system shall constitute failure of this test.

Figure 30-4-11. Insert Pullout Test


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Figure 30-4-12. Fastener Uplift Test


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e. For this test, retorquing of threaded elements subsequent to the completion of 500,000 cycles of load

shall not be permitted without the written approval of the engineer.

4.9.1.12 Fastening Longitudinal Restraint Test

Both before and after the performance of the Fastening Repeated Load Test, above, and without disturbing the

rail fastening assembly in any manner other than retorquing anchor bolts, the tie and fastening shall be

subjected to a longitudinal restraint test. A longitudinal load shall be applied as shown in Figure 30-4-14 in

increments of 0.4 kips (1.8 kN) with readings taken of longitudinal rail displacement after each increment.

Readings of rail displacement shall be the average of the readings of two dial indicators reading to ¹⁄₁ ,₀₀₀ of an

inch, (0.025 mm), one placed on each side of the rail with plungers parallel to the longitudinal axis of rail. The

load shall be applied in a direction coinciding with the longitudinal axis of the rail. The load shall be increased

M = FOR DETERMINATION OF P SEE ARTICLE 4.9.1.11a

Figure 30-4-13. Fastening Repeated Load Test


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incrementally until a load of 2.4 kips (10.7 kN) is reached. This load shall be held for not less than 15 minutes.

The rail shall not move than 0.20 inch (5 mm) during the initial 3-minute period, and there shall be no more

than 0.01 inch (0.25 mm) movement of the rail after the initial 3 minutes. The fastening shall be capable of

meeting the requirements of this test in either direction. If these criteria are met, the tie and fastenings will

have successfully passed this test.

4.9.1.13 Lateral Load Restraint Test

a. With a suitable length of new rail of the size to be used in the track affixed to the tie block in a manner

appropriate to the fastening being used, the entire assembly is supported and loaded as shown in

Figure 30-4-15. The loading head is to be fixed against translation and rotation. The wood block shall be

10″ × 10″ × ³ ⁄₄″ thick (254 mm × 254 mm × 19 mm) 5 ply, exterior grade plywood.

(1) A preload of 20 kips (89 kN) is to be applied to the rail to seat the rail in the fastening. Upon release

of the preload, a zero reading is to be taken on the dial indicators which measure rail translation.

Load is to be applied at a rate not to exceed 5 kips (22 kN) per minute until either 41 kips (182 kN)

has been applied or the rail base has translated ¹⁄₈ inch (3.18 mm), whichever occurs first. Inability

of the fastening to carry the 41 kip (182 kN) load with ¹⁄₈ inch (3.18 mm) or less of rail translation

shall constitute failure of this test. Complete failure of any component of the tie or fastening is cause

for rejection.

(2) With all load removed from the rail, a roller nest is placed between the fixed loading head and the

wood block on the rail head. The roller nest shall not offer resistance to lateral movement of the rail

head.

b. After taking zero reading on the dial indicators, which measure gage widening and rail translation, a

load of 20.5 kips (90.2 kN) is to be applied at a rate not to exceed 5 kips (22 kN) per minute. Rail rotation,

gage widening less rail translation, greater than ¹⁄₄ inch (6.35 mm) shall constitute failure of this test.

4.9.1.14 Electrical Impedance Test

a. Two short pieces of rail are affixed to Tie 2 using tie pads, insulators and fastenings in a manner

appropriate to the fastening system to be used.

b. The complete assembly shall be immersed in water for a minimum of 6 hours.

c. Within 1 hour after removal from water an a-c 10-volt 60-Hertz potential is applied across the two rails

for a period of 15 minutes. If the rails are rusty or contain mill scale, the contact points must be cleaned

d. The current flow in amperes is read using an a-c ammeter and the impedance determined by dividing the

voltage (10) by the current flow in amperes.

e. If the ohmic impedance determined in paragraph c exceeds 20,000 ohms, the tie will have passed the test

4.9.1.15 Tie Pad Test

a. The tie pad shall be loaded vertically using a rail section in a manner similar to its use in the fastening

system.

b. A cyclic load varying from 4 kips to 30 kips (17.8 kN to 134 kN) shall be applied continuously at a rate of

4 to 6 cycles per second for a total of 1,000 cycles.


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c. A static load shall be applied, at a rate between 3 and 6 kips/min (13.4 and 26.7 kN/min) in increments of

1 kip (4.45 kN) up to a maximum of 50 kips (223 kN). For each load increment, vertical pad deflection

shall be measured to the nearest 0.0001 inch (0.0025 mm) and recorded values for vertical load versus

Figure 30-4-14. Fastening Longitudinal Restraint Test


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deflection shall be plotted on a graph. Spring rate, as determined by the slope of the line connecting the

points representing pad deflections at 24 and 44 kips (107 kN and 196 kN) shall be calculated.

d. Load shall be released and pad deflection recorded 10 seconds after load removal.

e. The requirements of this test will have been met, if

(1) Pad returns to within 0.002 inch (0.051 mm) of its original position 10 seconds after load removal.

(2) Spring rate values determined from both pad tests, conducted as part of the design performance testsspecified in Article 4.9.1.3, do not vary by more than 25%.

(3) Spring rate values determined from initial tests in Article 4.9.1.3a conducted on the three test pads,

as part of the design performance tests specified do not vary by more than 25%.

(4) Spring rate values determined from final tests in Article 4.9.1.3h conducted on the two test pads, as

part of the design performance tests specified do not vary by more than 25%.

Figure 30-4-15. Fastening Lateral Restraint Test

norma arema para ensayo a flexion

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