The author’s database will undoubtedly serve as a valuable resource for geotechnical engineers involved with excavations, their support, and control of deformations. A number of points should, however, be considered when examining the various tables, plots, and preliminary conclusions presented in the paper. The degree of support preloading is especially important in understanding the behavior of excavation support systems. This is particularly well illustrated considering the source of the author’s Fig. 1. Using parametric finite-element analyses, Mana and Clough ~1981! suggested the following expression to estimate the maximum lateral movement of excavations in soft to firm clay: dHmax5dHesta Ma wa Sa Pa B (1) where dHmax5maximum estimated movement for design case; dHest5estimated lateral movement based on chart relating lateral movement, dH, and base stability factor of safety, FS ~e.g., Fig. 13!; a M5factor related to soil modulus of elasticity multiplier, M, with a range of 0.4 ‐1.7; a w5factor related to wall stiffness and strut spacing, EI/@s 4 gl#, with a range of 0.5‐1.1; a S5factor related to strut stiffness per unit of length, S/@s 4 gl#, with a range of 0.4 ‐1.2, base case of 1.0; a P5factor related to strut preload with a range of 1.0 ~no preload! to 0.5 for lateral movements and 0.25 for vertical movements when relatively high prestresses are applied; a B5factor related to excavation width ~B! with a range of 1.0 ~B50.75H, base case! to 2.0; H5total excavation depth ~wall height!; E5modulus of elasticity of the wall; I5internal moment of inertia of the wall per unit length; and s5average vertical spacing between struts. It is clear that Mana and Clough ~1981! considered that there are many factors that quantitatively influence deformation. Based on this work, Clough et al. ~1989! then combined several of these factors to relate lateral movement, wall stiffness, vertical strut spacing, and base stability factor of safety. By extension, several of the factors above should also be applied to the methods of Clough et al. ~1989!, whereby the predicted behavior of the basic system is provided by Fig. 1. If, for instance, an excavation support system in medium stiff clay (design pressure50.4gH) under consideration included preloading to 100% of the design load, the anticipated lateral movements could be about half those anticipated through use of Fig. 1.