Document: NUREG-0800
Document ID: 072325a8-02ea-4d59-bb3f-06592c340804
Document Type: srp
Title: The Aluminum Association, Specification for Aluminum Structures
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0520/ML052070327.pdf
Revision Date: 2023-06
Chapter: 3
Section ID: 3.4
CFR Part: 
CFR Title: 

Content:
braced by floors. He further states that actual peak acceleration should be used if any yielding or cracking of the walls is to be avoided. These requirements, according to Whitman (1991), can lead to quite large lateral soil pressures. Chang et al. (1990) described a study that evaluated the uncertainties of several analytical solutions by comparing the computed and recorded dynamic lateral soil pressures on the embedded wall of the Lotung, Taiwan 1/4-scale model structure during several moderate earthquakes. In this study, a 1/4-scale reactor containment model structure was embedded at a depth of 4.57 m (15 ft) below the ground surface. The analysis of recorded data showed that the 3.8.4-53 DRAFT Rev. 2 - April 1996 magnitude of dynamic lateral soil pressures was significantly lower than that predicted by published elastic solutions (ASCE 4-86 and EERL 73-50). The recorded dynamic lateral pressure increments were similar to, or lower than, those calculated by the M-O method. On the basis of the results of this study, Whitman concluded that it may suffice to use the M-O equation together with the actual expected peak acceleration Whitman 1991. Although the above conclusion may be generally true, it appears that Whitman's conclusion did not cover certain additional field data and discussions provided by Chang et al. (1990). These relate to (1) the effect of variation of the backfill shear modulus with depth and (2) the effect of the rocking motion on the dynamic lateral pressure distribution, which were measured at the Lotung site. The soil shear modulus is generally smaller at the ground surface because of low confining pressure and gradually increases with depth, contrary to the constant modulus assumption in elastic solutions. Probably because of this factor, the recorded dynamic earth pressures were substantially smaller than those given by the elastic solutions (Chang et al. 1990). On the basis of a detailed study of the Lotung site data, Chang et al. (1990)