x5bulldog
Structural
- Jan 8, 2008
- 27
I have read the post "Minimum shear reinforcement in pile caps?" posted on 1 APR 2012.
From reading posts, most prefer designing pile caps using the strut-and-tie model. Which is pretty basic for 2-pile, 4-pile arrangements or pretty much symmetric layouts. But at the same time there is CRSI which shows how to design pile caps based on flexure, one-way shear, two-way shear plus other special investigations to consider for one-way and two-way shear. CRSI has tables for different # of piles.
So my question is: Using the strut-&-tie model, I have a pile cap supported by two piles which is satisfactory. Now designing the pile cap based on CRSI, one way shear is No good so I need shear reinforcement. CRSI uses no shear reinforcement in their tables so the concrete can take all the shear . CRSI refers back to ACI 318 for one-way and two-way shear checks (but not the special investigation one-way two-way shear). ACI Chapter 15 section for shear in footings has pile caps (also footing supported on piles) mentioned in those sections which refers you back to Chapter 11 for shear design.
So I believed if using CRSI and then checking one-way shear, If the concrete alone cannot take the shear; Vu >= (phi)Vc/2 of section ACI 318 11.5 of minimum shear reinforcement need not be met......correct?
At the same time the governing building code which is the International Building Code (IBC) does not allow any soil beneath the pile cap to aid the piles.
From reading posts, most prefer designing pile caps using the strut-and-tie model. Which is pretty basic for 2-pile, 4-pile arrangements or pretty much symmetric layouts. But at the same time there is CRSI which shows how to design pile caps based on flexure, one-way shear, two-way shear plus other special investigations to consider for one-way and two-way shear. CRSI has tables for different # of piles.
So my question is: Using the strut-&-tie model, I have a pile cap supported by two piles which is satisfactory. Now designing the pile cap based on CRSI, one way shear is No good so I need shear reinforcement. CRSI uses no shear reinforcement in their tables so the concrete can take all the shear . CRSI refers back to ACI 318 for one-way and two-way shear checks (but not the special investigation one-way two-way shear). ACI Chapter 15 section for shear in footings has pile caps (also footing supported on piles) mentioned in those sections which refers you back to Chapter 11 for shear design.
So I believed if using CRSI and then checking one-way shear, If the concrete alone cannot take the shear; Vu >= (phi)Vc/2 of section ACI 318 11.5 of minimum shear reinforcement need not be met......correct?
At the same time the governing building code which is the International Building Code (IBC) does not allow any soil beneath the pile cap to aid the piles.
