A study is conducted on systems of concentric annular and circular foundations on the surface of a stratum. The dynamic flexibilities of each of the foundations in the presence or absence of the other are compared. Furthermore, the motion of the circular foundation due to loads on the annular foundation is examined in comparison with the displacements and rotations resulting from the same loads on a single circular foundation of radius equal to the outer radius of the annular foundation. The effects of structural inertia on the interaction between the foundations are explored both for loads on the structure, which is supported on the annular foundation, and for ground motion.

Recommendations are presented for determining unit point and shaft resistances for precast prestressed concrete piles embedded in the Yorktown Formation, the bearing stratum for most major structures in tidewater Virginia. The soil is subject to loss of strength during performance of the Standard Penetration Test (SPT) due to the creation of excess pore pressures that result in a significant reduction of the SPT resistance values. Pile driving has a similar effect on the soils, and this was documented in the study. Thus, ultimate pile capacities determined by dynamic methods will be significantly underestimated. New design parameters are developed by load testing three instrumented piles and correlating the results with the SPT resistance. The SPT correlation factors are then used to reevaluate the capacity of previous load tests and provide good estimates of ultimate pile capacity. The design parameters are considered applicable for use through the region with the few exceptions noted.

The present study examines the lateral earth pressure transferred to a rigid retaining wall by granular fill confined between the wall and an adjacent rock face. The centrifuge modeling technique is used to test small models in which rotation of the wall about its base can be controlled, thus allowing observation of changes in pressure from the at‐rest to the active condition. Janssen's silo pressure equation may be reasonably used for estimation of the atrest pressure, using an earth pressure coefficient, $K=1-\sin \Phi \text{.}$ Significant variations from the estimated pressure may occur next to the wall as a result of small variations in placement conditions. A conservative approach may be to use a decreased Φ value in calculating K. In the active condition, progressive failure in the soil results in a decreased Φ, which should be used when estimating wall pressure. These estimates may be obtained from stress characteristic solutions, or from the silo pressure equation in which a K value compatible with the values of Φ and δ (wall fraction angle) is used.

Observations on a new cellular wharf bulkhead adjacent to an older similar structure provide the opportunity to assess the suitability of a newly proposed design procedure. Data are obtained that justify the use of the new procedure and demonstrate its importance through the savings of 272 Mg (300 tons) of steel on the project. The observations add significantly to the store of performance data for cellular bulkheads and cofferdams. It is shown that cellular structures can accommodate relatively large settlements and lateral movements and that a stiff concrete deck substantially minimizes differential lateral movement. Deep underwater compaction of cohesionless cell fills essentially eliminates settlement due to fill compression. Adequate forecasts of deflection of cells can be made by relatively simple methods; however, settlement forecasts on sands are less reliable.

Analysis of test results for intact and granulated marbles (cemented and noncemented granular materials) adds to the indications that strain softening does not express a real material behavior; it highlights similarities in stressstrain relations and confirms equality of a stress and a plastic strain invariant. The physical meaning of the parameters of a yield equation, which express energy dissipating in frictional and nonfrictional processes and define the deviation from the normality condition, is shown. A hardening rule that takes into account friction and dilatancy is formulated from yield relations and from an experimentally proved consistency condition. Variation of constitutive parameters and evolution of various yield states is considered together with application of the hardening rule. Variation of the normality condition deviation angle along yield states obtained under low and very high confinement is constitutively modeled. Meridian and deviatoric sections of yield surfaces, obtained by low and high pressure experiments and substantiated by results compiled from the literature, are considered. A polyaxial yield equation and hardening rule are proposed and experimentally verified.

A numerical method is presented for the analysis of general three‐dimensional pile groups. The features of the pile‐group model may include battered piles, different pile sizes, non‐uniform pile sections, soil nonlinearity, soil inhomogeneity, and pile‐soil‐pile interaction. A typical six‐pile group is analyzed and compared with results from three other computer programs for pilegroup analysis that are based on different approaches. This method is then used to analyze field and laboratory tests on groups of battered and vertical piles. The computed solutions are shown to be in good general agreement with the measured data.

A numerical method to calculate the load-settlement of an axially loaded pile is presented. The method is based on an iterative scheme that tests the global equilibrium conditions and the load transfer (t-z) equations. The scheme is both accurate and computationally very economical.