Some important points and bases of the "Design Guide for the Building Foundation against Seismic Force" enforced in September 1984 are introduced in this report.

As historical background, the two events accelerated to establish the Guide. The first is the enforcement of the New Earthquake Resistance Standard for building in 1981, and the second is the experience of damage of concrete piles due to the Off-Miyagi prefecture earthquake in 1978.

The Guide is composed of eight chapters. In Chapter 1, basic policies are described to provide structural safety of building foundation equal to or higher than that of superstructure, in allowable capacity design. Chapter 2 prescribes the setting of design external forces to be applied to building foundation. As for pile foundation, reduction of horizontal force to piles by effects of embedded portion is also described.

Design of spread foundation is introduced in Chapter 3, and design of pile foundation is introduced in Chapter 4, respectively. Since more problems are involved in pile foundation than spread foundation, more pages are assigned for pile foundation, i.e., bearing capacity, pull-out resistance,horizontal resistance and combined stresses of piles.

Allowable stresses of various pile materials are summarized in Chapter 5.

In Chapter 6 to Chapter 8, precautions for design of pile head joint,design of underground walls, and cutting method of pile head, are described respectively.

^*1 Head of Geotechnical Engineering Division, Structural Engineering Department, Building Research Institute, Ministry of Construction