Pile load tests - When are they required?

[cliff234]

I am confused as to when IBC 2009 requires pile load tests.

At first reading, Section 1810.3.3.1.1 implies that load tests are required only for piles with capacities greater than 40 tons. Upon closer reading however, one could make the case that all piles need to be load tested for axial load. Yes, I am parsing the grammatical structure of Section 1810.3.3.1.1. Section 1810.3.3.1.2 further implies that load tests for determining allowable compressive strengths of piles are not always required. I am inclined to believe that my first interpretation (load tests are only required for piles > 40 ton capacity) is correct.

Section 1810.3.3.1.5 discusses tension capacities of piles and states that either an approved method of analysis may be used to determine tension capacity or a load test may be used.

Section 1810.3.3.2 discusses allowable lateral loads of piles and states that the either an approved method of analysis may be used to determine the lateral load capacity or a load test may be used.

My understanding is that issues related to whether load tests are required are in Chapter 18. Chapter 17 (Special Inspections) deals only with how to inspect piles as the work is being performed and does not deal with when load test are required. In other words, IF you do a pile load test, then you need to follow Table 1704.8.

I would appreciate feedback as to whether or not my interpretations are correct.

Also, thank you to those who answered my previous question (the first that I asked on this forum) several weeks ago! This is a very useful website!

 

[JAE]

I think 1810.3.3.1.2 states three criteria where load tests kick in:

1. If you exceed compressive stresses shown in Table 1810.3.2.6
2. Where the design load for any deep foundation element is in doubt (i.e. you aren't sure of the soil capacity via approved equations)
3. You use a cast-in-place deep foundation with enlarged bases made of compacted concrete or precast base.

Also - section 1810.1.2 suggests load tests for re-use of existing foundations but that may not be what you are looking at here.

I think item 2 above is the main culprit when it comes to load tests.

If a geotechnical engineer offers specific design criteria (end bearing capacity, skin friction, etc.) for cast type foundations or you are less than 40 tons for driven piling, then load tests are not required.