Load Test For Suspended Cradle

 

Load test for Suspended cradle

 

Documents Needed for Load testing

Cradle Manual  Design calculation of Support system  Wire rope certificate 

 

CHECK LIST 

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Check the manual and confirm that installation made as per the manual. Before going to load test, make sure that no major

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remarks in visual and functional test Make sure that the weather condition is as per the limit of manual

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Check the weight of all components in manual and

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calculate WLL as shown in figure Check the breaking strength and capacity of wire rope.

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WLL= Weight of platform + weight of suspension mechanism including motor winch and safety devices + Rated load

 

General procedures for testing 1.

Keep the cradle on ground such way that its wheels complete rest over ground

2.

3.

Load the platform with maximum rated capacity as mentioned as per manufacture. Load must be distributed equally on over all area of platform

4.

No person is permitted inside the cradle during load testing

5.

Check the cradle after 15 minutes if load causes any failure

6.

or visible damage to structure. Operate cradle by using remote up to one meter .

7.

Check the support have any extra movement movement or bending during up ward movement

8.

Also check the wire rope have any slippage slipp age over the winch during motion.

9.

If any of above observed during test consider as load test failure.

 

Calculation of testing load in Counter Weight support cradle 

WLL=3× WL L=3×b× b× Coun Counter ter weig weight/(a ht/(a))

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Test load=W load=WLL-W LL-Weight eight of platformplatform- weigh weightt of suspension mechanism including motor winch win ch and safe safety ty device devicess

 

Cont.. 

If the length of wire rope is i s exceed above

50 meter. Have to subtract it from the work load limit That is Tested Teste d load load =WLL=WLL- Weig Weight ht of platform platform-weight of suspension mechanism including motor mot or winc winch h and saf safety ety dev device icess- Weig eight ht of wire rope

 

Davit and Parapet support Check the maximum load carrying capacity of I beam .  Check the dimension of bolts and its maximum tension bearing capacity.  Check the rated capacity of cradle satisfying sati sfying the stability equations .  Apply the load same as rated capacity mention in manufacture manual(If manual(If it is satisfying)  If the cradle height is more than 50 m then Tested load =Rated load-(Wight load-(Wight of rope per meter× length) 

 

Davit support stability criteria

 

Parapet support Stability criteria

 

APPENDIX

 

Technical data of cradle

Table 1

 

Table 2

 

Cont..

Table 3

 

EXAMPLE

 

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A Suspended cradle have capacity of 630 kg support from from Davit support fixed fixed with 4 Nos of M 16 ,4.6 grade bolts with spacing of 100 mm .The length of I beam is 2 meter. meter. Check its stability .

Answer R1=25100 N (From Table 2).N=4 Total reaction R=N*R1=100,400 N a=2 m, b=0.1 m,W=630 Kg Stability Factor=R*b/W*a = 100400*0.1/630*2 =8 Which is greater greater than 3 so it is stable and can proceed for load testing.