Pile Group Orientation and Literature - Bridge Engineering Specific

[Farhaad Shaik]

Hi All,

I have just signed up and I am a new member so apologies in advance if I am asking a question that has already been answered before. Just that I am under time pressure to develop and understanding of the subject I will be discussing below and kindly request any assistance or guidance on the following:

Firstly, I am a bridge engineer and have completed the design of a 3-span post tensioned beam and slab bridge until pilecap level. We have appointed a contractor for the geotechnical drilling investigation and within a month or so will be in a position to access results for UCS tests on rock samples as client regulations dictates all bridges be socketed into rock and given that the said bridge is a river bridge, it is more logical to rely on end bearing.

Before reaching out today, I have attempted to find research literature for some guidance regarding below but realized that I have spent alot of time on research with no tangible results to completing my task. My question are as follows:

1. On skew bridges - what are the benefits of option 1 and 2 and when would one use each pile group arrangement. I suspect it has to do with the resolution of forces perpendicular or at an angle to each pile but the complication comes in with the high bending moment of the abutment wall on the pilecap and the axial load from the deck (DL + Traffic + Supplementary Actions) are greater than the horizontal force.

2. I am aware that there are a lot of textbooks that cover pile design. Is there a small list of textbooks with demonstrative examples I can consult to guide me through the design of a pile group from start to end and outlining important considerations?

3. I am expecting to receive modulus of sub-grade reactions from the geotechnical engineer upon the completion of the grilling investigations which I will use when I set up a 3D model of the pilecap and piles. I have read that when piles are very closely spaced, then the stiffness of adjacent piles are reduced by half or a quarter to possibly simulate a disturbance in the ground. Is there any literature, rule of thumb I can follow?...unfortunately, I cant remember where I read this from.

Thank you and eagerly await responses/comments.

 

[SlideRuleEra]

"Lateral Load Capacity of Piles"

You should be working with an engineer who has more applied engineering experience on this subject. You have done much study, and that is good, but this will take you only so far. The "jump" from theory to application of theory is not something that can described in a paper or book.

 

[BNGeo]

FHWA and AASHTO LRFD Design manuals for lateral load analysis using soil-pile interaction, including modifiers to account for pile spacing. But, overall I agree with the above comment that this is not something that is quickly jumped into without any additional guidance.