Masaru Kitaura

Erratum: “Earthquake-Induced Structural and Nonstructural Damage in Hospitals” [Earthquake Spectra 27, 617–634 (2011)]

1. The first paragraph on page 624 should be replaced with the following text: As a result of this earthquake, the first “Hospital Seismic Safety Act” was developed (California Seismic Safety Commission 2001), with a focus on structural and nonstructural resistance (Meehan 1984); however, the 1994 Northridge Earthquake demonstrated that the Act was successful in protecting structures, but damage to nonstructural components, such as plumbing and ceiling systems, was still extensive in post-1973 buildings (California Seismic Safety Commission 2001). The Act was amended by Senate Bill 1953 after the Northridge Earthquake to require seismic evaluations; if hospitals were then found to have structural or nonstructural vulnerabilities, retrofits or replacements were also required. In essence, the legislation in California has been developed from lessons learned from previous experience and reflected the complexity of hospitals systems. There is a need, therefore, for other regions of the world that are threatened by earthquakes to develop and enforce hospital resilience legislation based in part on lessons learned from Iran, Algeria, Japan, Taiwan, California, and other regions.

Rocking Component of Earthquake Induced by Horizontal Motion in Irregular Form Ground

Two horizontal components and a vertical component are usually employed in seismic observations. Therefore, only those components are used as the input ground motions in seismic design code. However, there must be rotational or rocking component together with basic three components in ground motion, because of the existence of Rayleigh wave, phase difference between vertical components at grounds with different stiffness, and no mechanism preventing ground motion from being horizontal for excitations from various directions. Seismographs are generally installed more than several hundred meters apart from each other even in arrayed observations. This distance is too long to identify the existence of rotational or rocking component. And there is no seismograph which can measure this component. Since there has been no information on this component, such component cannot be taken into account in seismic design code. However such component may have an impact on some rigid structures as well as flexible structures. It is indispensable to examine the effects of this component on structural response. In this study, experiments using the model ground excited by a shaking table and simulations of ground motion using FEM are carried out, in which existence of rocking components are examined in earthquake motion generated at various grounds such as the ground with irregular form foundation. Consequently, the experiment and analysis verified existence of rocking motion component. It is shown that the vibration of horizontal direction is the generating factor of rocking motion components in the experiment and that the vibration of vertical direction is the amplifying factor of rocking motion components. Moreover, rocking motion component is large near the border between two different grounds, and depends on the vertical amplitude of vibration and on excitation frequency.

A Study on Flood Control of the Joganji-River from Feudal Period to Meiji Era

1. 常願寺川の概要 富山県の河川は3,000m級 の急峻な山岳地帯を流 れ下 り、わずかな平地部を貫いて海に注ぐ急流河川が多 く、有史以来これ らの河川は、幾度となく氾濫を繰 り返 してきた。江戸時代の著名な学者である室鳩巣(む ろき ゅうそう)が 、 「越中百里山河壮な り」と称 したように、 東西90km、 南北76kmの 富山県内には大小幾多の河川 が流れてお り、それ らの河川における治水の重要性こそ が、1883(明 治16)年 に石川県か ら富山県が分離、独立 し た契機ともなったのである。1) 富山県の誕生後も治水事業は富山県の最重点施策とし て取り組まれてきた。富山県となった明治16年 か ら特に 水害の発生が多かった20年 間について県の決算を調べ てみると、県財政の平均5割 が河川費に充てられ、時に は8割 になったときもあった(表-1参 照)。2) このように富山県の歴史は、洪水のたびごとに氾濫し、 流路を変えて奔流する河川との闘いの歴史で もあった。 なかでもわが国の代表的な急流荒廃河川であり、治水史 に残る常願寺川について述べる。 富山 ・岐阜両県境北アルプスの北ノ俣岳(標高 表-1 富山県 歳 出額 中 、常願 寺川河 川費 の割合(決 算)