Abstract
This paper is the third report in a series of studies on vertically loaded pile caps. In this paper, we discussed the initial cracking load of four pile caps. The experimental results by the authors' tests were compared with the calculated values from the three dimentional elastic finite element analysis and the equation to estimate the initial cracking load was derived on referring to the results of the finite element analysis. The calculated initial craking loads according to the equation derived by the authors were compared with those calculated from the finite element analysis, with the experimental results and with the design loads calculated on the provision for the moment in A. I. J. Building Code Requirements for Reinforced Concrete. The results obtained are as follows : 1) The calculated initial cracking loads according to the derived equation agree both with those calculated from the finite element analysis and with the experimental results. 2) In order to avoid the crack development under the design load, the pile cap must have the special design so that either the depth of slab is not thicker than the constant value calculated from the dimensions of pile cap, or the reinforcement ratio is smaller than the constant value calculated also from the cap dimensions.
