Lateral pile load test - Deflection measurement

[vinothsekar]

Hi,

We are doing a Lateral pile load test on land pile of dia 1.4m for a marine stimulated condition by considering the dredge level 14.5 m by providing the outer casing dai 1.6m upto the above dredge level.

Design load is 10 T and Test load is 20T.

We are going to fix two dial gauges, one at the cut off level and other at 2.0m below cut off level. By consider the depth of fixity, the dredge level deflection will be interpolated by linear interpolation method with the help of two fixed dial gauges at different pile top level.

Please give the suggestion that without providing strain gauges or Inclinometer, Is it possible to measure the lateral deflection by linear interpolation method.

Also, Please suggestion the other method to measure the lateral deflection of the marine piles.

Vinothkumar S
Geotechnical Engineer

 

[Settingsun]

Does this actually simulate the marine pile accurately enough? I'd have thought the extra 14.5m of overburden on the land pile test will reduce the land pile deflection.

 

[oldestguy]

At least for a back up, set up a surveyor's transit some distance away to sight on a horizontal surveyor's rod periodically in the test. Sight on a fixed reference beyond also. I should add the deflection required for a "good" test may be far beyond the capabilities of dial gauges. I'd be prepared for maybe a half meter deflection as a possibility.

 

[aeoliantexan]

If I understand correctly, the test pile will be cantilevered above the 14.5 M depth. With a lateral load applied at the top, the moment will increase with depth, and the radius of curvature and slope will also increase with depth. The pile won't be linear, so you can't calculate the deflection at 14.5 meters by assuming it is linear. However, you should be able to calculate the shape of the cantilevered pile quite accurately if you know the properties of the section, because you will know the moment and shear at all depths down to 14.5 meters. You probably can use the equations for deflection of a cantilever beam from the Steel Design Manual or other reference. Knowing the calculated deflection and the slope at the dredge line, you should be able to calculate the deflection at the dredge line.

I share Steve49's concern that this may not be an accurate simulation of the behavior of the marine pile.

 

[vinothsekar]

Hi everyone,

Thank you for your valuable feedback.

Vinothkumar S
Geotechnical Engineer

 

[Geosubhtech]

If i understood properly, irrespective of predicting deflection along the pile the pile measurement at pile head (deflection, slope, B.M.) can allow you to produce a pile soil response to predict the deflection and capacity. The reference could be done to
L. C. Reese and W. R. Cox, "Soil Behavior from Analysis of Tests of Uninstrumented Piles under Lateral Loading," in Performance of Deep Foundations, ed. R. Lundgren and E. D'Appolonia (West Conshohocken, PA: ASTM International, 1969), 160-176.
I had never adopted this in work but i read this for understanding. Hope this will give some help.

But have seen many case studies which use the method as told by Oldestguy.