地震工学 is an 学際的 branch of engineering that designs and analyzes structures, such as buildings and bridges, with 地震 in mind. Its overall goal is to make such structures more resistant to earthquakes. An earthquake (or seismic) engineer aims to construct structures that will not be damaged in minor shaking and will avoid serious damage or collapse in a major earthquake. Earthquake engineering is the scientific field concerned with protecting society, the natural environment, and the man-made environment from earthquakes by limiting the 地震リスク to 社会的に-経済的に acceptable levels.1 Traditionally, it has been narrowly defined as the study of the behavior of structures and geo-structures subject to 地震荷重; it is considered as a subset of 構造工学, 地盤工学, 機械工学, 化学工学, 応用物理学, etc. However, the tremendous costs experienced in recent earthquakes have led to an expansion of its scope to encompass disciplines from the wider field of 土木工学, 機械工学, 原子力工学, and from the 社会科学, especially 社会学, 政治学, 経済, and ファイナンス.2
地震工学の主な目的は次のとおりです。
Foresee the potential consequences of strong 地震 on 都市部 and civil infrastructure.
Design, construct and maintain structures to 実行 at earthquake exposure up to the expectations and in compliance with 建築基準法.3
A 適切に設計された構造 does not necessarily have to be extremely strong or expensive. It has to be properly designed to withstand the seismic effects while sustaining an acceptable level of damage.
地震荷重
地震荷重 means application of an earthquake-generated excitation on a structure (or geo-structure). It happens at contact surfaces of a structure either with the ground,5 with adjacent structures,6 or with 重力波 from 津波. The loading that is expected at a given location on the Earth's surface is estimated by engineering 地震学. It is related to the 地震災害 of the location.
耐震性能
地震 or 耐震性能 defines a structure's ability to sustain its main functions, such as its 安全性 and 保守性, で and 後 a particular earthquake exposure. A structure is normally considered 安全 if it does not endanger the lives and よく- of those in or around it by partially or completely collapsing. A structure may be considered 修理可能 if it is able to fulfill its operational functions for which it was designed.
主要な建築基準法に実装されている地震工学の基本概念は、建物が重大な損傷を被ることによって、しかし全体的に崩壊することなく、まれな非常に深刻な地震に耐えなければならないことを前提としています。7 On the other hand, it should remain operational for more frequent, but less severe seismic events.
耐震性能評価
エンジニアは、特定の地面の揺れにさらされる個々の建物への直接的な損傷に関連する実際のまたは予想される耐震性能の定量化されたレベルを知る必要があります。 このような評価は、実験的または分析的に実行できます。
実験的評価
Experimental evaluations are expensive tests that are typically done by placing a (scaled) model of the structure on a シェイク-テーブル that simulates the earth shaking and observing its behavior.8 Such kinds of experiments were first performed more than a century ago.9 Only recently has it become possible to perform 1:1 scale testing on full structures.
このような試験は費用がかかるため、主に構造物の地震挙動の理解、モデルの検証、解析方法の検証に使用される傾向があります。 したがって、適切に検証されると、計算モデルと数値手順は、構造物の耐震性能評価に大きな負担をかける傾向があります。
分析的/数値的評価
耐震性能評価 or 地震構造解析 is a powerful tool of earthquake engineering which utilizes detailed modelling of the structure together with methods of structural analysis to gain a better understanding of seismic performance of building and 非-建物構造。 正式な概念としての技術は、比較的最近の開発です。
In general, seismic structural analysis is based on the methods of 構造ダイナミクス.10 For decades, the most prominent instrument of seismic analysis has been the earthquake 応答スペクトル method which also contributed to the proposed building code's concept of today.11
However, such methods are good only for linear elastic systems, being largely unable to model the structural behavior when damage (i.e., 非-線形性) appears. Numerical ステップ- by -ステップ統合 proved to be a more effective method of analysis for multi-degree-of-freedom 構造システム with significant 非-線形性 under a 一時的 process of ground motion excitation.12 Use of the 有限要素法 is one of the most common approaches for analyzing non-linear 土壌構造の相互作用 computer models.
基本的には、建物の耐震性能を評価するために数値解析を行っています。 パフォーマンス評価は、通常、非線形静的プッシュオーバー分析または非線形時間-履歴分析を使用して実行されます。 このような解析では、梁、柱、梁-柱の接合部、せん断壁などの構造コンポーネントの正確な非線形モデリングを実現することが不可欠です。したがって、実験結果は決定において重要な役割を果たします。個々のコンポーネントのモデリングパラメータ、特に重要な非-線形変形を受けるコンポーネント。 次に、個々のコンポーネントを組み立てて、構造の完全な非-線形モデルを作成します。 このように作成されたモデルは、建物のパフォーマンスを評価するために分析されます。
The capabilities of the structural analysis software are a major consideration in the above process as they restrict the possible component models, the analysis methods available and, most importantly, the numerical robustness. The latter becomes a major consideration for structures that venture into the non-linear range and approach global or local collapse as the numerical solution becomes increasingly unstable and thus difficult to reach. There are several commercially available Finite Element Analysis software's such as CSI-SAP2000 and CSI-PERFORM-3D, MTR/SASSI, Scia Engineer-ECtools, ABAQUS, and Ansys, all of which can be used for the seismic performance evaluation of buildings. Moreover, there is research-based finite element analysis platforms such as OpenSees, MASTODON, which is based on the MOOSEフレームワーク、RUAUMOKOおよび古いDRAIN-2D / 3D、これらのいくつかは現在オープンソースです。
地震工学研究
地震工学の研究とは、地震工学に関連する事実の発見と科学的説明、新しい発見に照らした従来の概念の改訂、および開発された理論の実用化を目的とした、フィールドおよび分析の両方の調査または実験を意味します。
The 国立科学財団 (NSF) is the main United States government agency that supports fundamental research and education in all fields of earthquake engineering. In particular, it focuses on experimental, analytical and computational research on design and performance enhancement of structural systems.
The 地震工学研究所 (EERI) is a leader in dissemination of 地震工学研究 related information both in the U.S. and globally.
A definitive list of earthquake engineering research related 揺れるテーブル around the world may be found in Experimental Facilities for Earthquake Engineering Simulation Worldwide.14 The most prominent of them is now E-Defense Shake Table15 in 日本.
米国の主要な研究プログラム
NSF also supports the George E. Brown, Jr. 地震工学シミュレーションのためのネットワーク
The NSF Hazard Mitigation and Structural Engineering program (HMSE) supports research on new technologies for improving the behaviour and response of structural systems subject to earthquake hazards; fundamental research on safety and reliability of constructed systems; innovative developments in 分析 and model based simulation of structural behaviour and response including soil-structure interaction; design concepts that improve 構造性能 and flexibility; and application of new control techniques for structural systems.16
(NEES) that advances knowledge discovery and innovation for 地震 and 津波 loss reduction of the nation's civil infrastructure and new experimental simulation techniques and instrumentation.17
NEESネットワークは、地理的に-分散、共有-された14の使用ラボを備えており、いくつかのタイプの実験作業をサポートしています。17 geotechnical centrifuge research, シェイク-テーブル tests, large-scale structural testing, tsunami wave basin experiments, and field site research.18 Participating universities include: コーネル大学; リーハイ大学; オレゴン州立大学; レンセラー工科大学; バッファロー大学, ニューヨーク州立大学; カリフォルニア大学バークレー校; カリフォルニア大学デービス校; カリフォルニア大学ロサンゼルス校; カリフォルニア大学サンディエゴ校; カリフォルニア大学サンタバーバラ校; イリノイ大学アーバナ校-シャンペーン; ミネソタ大学; ネバダ大学リノ校; and the テキサス大学オースティン校.17
The equipment sites (labs) and a central data repository are connected to the global earthquake engineering community via the NEEShub website. The NEES website is powered by HUBzero software developed at パデュー大学 for nanoHUB specifically to help the scientific community share resources and collaborate. The cyberinfrastructure, connected via インターネット2は、インタラクティブなシミュレーションツール、シミュレーションツール開発エリア、厳選された中央データリポジトリ、アニメーションプレゼンテーション、ユーザーサポート、テレプレゼンス、リソースのアップロードと共有のメカニズム、およびユーザーと使用パターンに関する統計を提供します。
このサイバーインフラストラクチャにより、研究者は次のことが可能になります。中央の場所にある標準化されたフレームワーク内でデータを安全に保存、整理、共有する。 同期されたリアルタイムのデータとビデオを使用して、リモートで実験を観察し、参加します。 研究実験の計画、実行、分析、および公開を容易にするために同僚と協力します。 複数の分散実験の結果を組み合わせ、物理実験をコンピューターシミュレーションとリンクさせて、システム全体のパフォーマンスを調査できるようにする計算シミュレーションとハイブリッドシミュレーションを実行します。
これらのリソースは共同で、土木および機械インフラストラクチャシステムの耐震設計と性能を改善するためのコラボレーションと発見の手段を提供します。
地震シミュレーション
The very first 地震シミュレーション were performed by statically applying some 水平慣性力 based on スケーリング 地動加速度のピーク to a mathematical model of a building.19 With the further development of computational technologies, 静的 approaches began to give way to 動的 ones.
Dynamic experiments on building and non-building structures may be physical, like シェイク-テーブルテスト, or virtual ones. In both cases, to verify a structure's expected seismic performance, some researchers prefer to deal with so called "real time-histories" though the last cannot be "real" for a hypothetical earthquake specified by either a building code or by some particular research requirements. Therefore, there is a strong incentive to engage an earthquake simulation which is the seismic input that possesses only essential features of a real event.
地震シミュレーションは、強い地球の揺れの局所的な影響の再現として理解されることがあります。
構造シミュレーション
Theoretical or experimental evaluation of anticipated seismic performance mostly requires a 構造シミュレーション which is based on the concept of structural likeness or similarity. 類似性 is some degree of 類推 or 類似性 between two or more objects. The notion of similarity rests either on exact or approximate repetitions of パターン in the compared items.
In general, a building model is said to have similarity with the real object if the two share 幾何学的類似性, 運動学的類似性 and 動的類似性. The most vivid and effective type of similarity is the キネマティック one. 運動学的類似性 exists when the paths and velocities of moving particles of a model and its prototype are similar.
The ultimate level of 運動学的類似性 is 運動学的同等性 when, in the case of earthquake engineering, time-histories of each story lateral displacements of the model and its prototype would be the same.
地震振動制御
地震振動制御 is a set of technical means aimed to mitigate seismic impacts in building and 非-建物 structures. All seismic vibration control devices may be classified as 受け身, アクティブ or ハイブリッド21 where:
パッシブコントロールデバイス have no フィードバック capability between them, structural elements and the ground;
アクティブ制御デバイス incorporate real-time recording instrumentation on the ground integrated with earthquake input processing equipment and アクチュエータ within the structure;
ハイブリッド制御装置 have combined features of active and passive control systems.22
When ground 地震波 reach up and start to penetrate a base of a building, their energy flow density, due to reflections, reduces dramatically: usually, up to 90 percent . However, the remaining portions of the incident waves during a major earthquake still bear a huge devastating potential.
After the seismic waves enter a 上部構造, there are a number of ways to control them in order to soothe their damaging effect and improve the building's seismic performance, for instance:
to 消散する the wave energy inside a 上部構造 with properly engineered ダンパー;
波エネルギーをより広い周波数範囲に分散させる。
to 吸収する the 共鳴 portions of the whole wave frequencies band with the help of so-called マスダンパー.23
調整された（受け身), as AMD for the アクティブ, and as HMD for the ハイブリッドマスダンパー, have been studied and installed in 高層ビル-、主に日本で、四半世紀の間。24
However, there is quite another approach: partial suppression of the seismic energy flow into the 上部構造 known as seismic or 免震.
For this, some pads are inserted into or under all major load-carrying elements in the base of the building which should substantially decouple a 上部構造 from its 下部構造 resting on a shaking ground.
The first evidence of earthquake protection by using the principle of base isolation was discovered in Pasargadae、現在はイランである古代ペルシャの都市で、紀元前6世紀にまでさかのぼります。 以下に、今日の地震振動制御技術のサンプルをいくつか示します。
ペルーの乾燥した-石の壁
ペルー is a highly 地震 land; for centuries the dry-stone 工事 proved to be more earthquake-resistant than using mortar. People of インカ文明 were masters of the polished 'dry-stone walls', called 切石, where blocks of stone were cut to fit together tightly without any モルタル。 インカは世界が今まで見た中で最高の石工の1つでした25 and many junctions in their masonry were so perfect that even blades of grass could not fit between the stones.
The stones of the dry-stone walls built by the Incas could move slightly and resettle without the walls collapsing, a passive 構造制御 technique employing both the principle of energy dissipation (coulomb damping) and that of suppressing 共鳴 amplifications.26
動吸振器
Typically the 動吸振器 are huge concrete blocks mounted in 高層ビル or other structures and move in opposition to the 共振周波数 oscillations of the structures by means of some sort of spring mechanism.
The 台北101 skyscraper needs to withstand 台風 winds and earthquake 震え common in this area of Asia/Pacific. For this purpose, a steel 振り子 weighing 660 metric tonnes that serves as a tuned mass damper was designed and installed atop the structure. Suspended from the 92nd to the 88th floor, the pendulum sways to decrease resonant amplifications of lateral displacements in the building caused by earthquakes and strong 突風.
ヒステリシスダンパー
A ヒステリシスダンパー is intended to provide better and more reliable seismic performance than that of a conventional structure by increasing the dissipation of 地震入力 energy.27 There are five major groups of hysteretic dampers used for the purpose, namely:
流体粘性ダンパー（FVD）
粘性ダンパーには、補助ダンピングシステムであるという利点があります。 それらは楕円形のヒステリシスループを持ち、減衰は速度に依存します。 多少のメンテナンスが必要になる可能性がありますが、通常、地震後に粘性ダンパーを交換する必要はありません。 他のダンピング技術よりも高価ですが、地震荷重と風荷重の両方に使用でき、最も一般的に使用されるヒステリシスダンパーです。28
フリクションダンパー（FD）
Friction dampers tend to be available in two major types, linear and rotational and dissipate energy by heat. The damper operates on the principle of a クーロンダンパー. Depending on the design, friction dampers can experience スティック-スリップ現象 and 冷間溶接。 主な欠点は、摩擦面が時間の経過とともに摩耗する可能性があることです。このため、風荷重の放散には推奨されません。 地震用途で使用する場合、摩耗は問題ではなく、必要なメンテナンスはありません。 それらは長方形の履歴ループを持ち、建物が十分に弾力性がある限り、地震の後に元の位置に落ち着く傾向があります。
金属降伏ダンパー（MYD）
Metallic yielding dampers, as the name implies, yield in order to absorb the earthquake's energy. This type of damper absorbs a large amount of energy however they must be replaced after an earthquake and may prevent the building from settling back to its original position.
粘弾性ダンパー（VED）
粘弾性ダンパーは、風と地震の両方の用途に使用できるという点で便利です。通常、小さな変位に制限されます。 一部のブランドは米国の建物での使用が禁止されているため、テクノロジーの信頼性について懸念があります。
振り子ダンパーにまたがる（スイング）
免震
免震は、地震の運動エネルギーが建物の弾性エネルギーに伝達されるのを防ぐことを目的としています。 これらの技術は、構造物を地面から隔離することでこれを実現し、ある程度独立して移動できるようにします。 エネルギーが構造物に伝達される程度とエネルギーがどのように放散されるかは、使用される技術によって異なります。
鉛ゴムベアリング
Lead rubber bearing or LRB is a type of 免震 employing a heavy ダンピング. It was invented by ビル・ロビンソン、ニュージーランド人。29
Heavy damping mechanism incorporated in 振動制御 technologies and, particularly, in base isolation devices, is often considered a valuable source of suppressing vibrations thus enhancing a building's seismic performance. However, for the rather pliant systems such as base isolated structures, with a relatively low bearing stiffness but with a high damping, the so-called "damping force" may turn out the main pushing force at a strong earthquake. The video30 shows a Lead Rubber Bearing being tested at the UCSD Caltrans-SRMD facility. The bearing is made of rubber with a lead core. It was a uniaxial test in which the bearing was also under a full structure load. Many buildings and bridges, both in New Zealand and elsewhere, are protected with lead dampers and lead and rubber bearings. テパパトンガレワ, the national museum of New Zealand, and the New Zealand 国会議事堂 have been fitted with the bearings. Both are in ウェリントン which sits on an 活断層.29
スプリング- with -ダンパー免震装置
Springs-with-damper base isolator installed under a three-story town-house, サンタモニカ, California is shown on the photo taken prior to the 1994 ノースリッジ地震 exposure. It is a 免震 device conceptually similar to 鉛ゴムベアリング.
One of two three-story town-houses like this, which was well instrumented for recording of both vertical and horizontal 加速 on its floors and the ground, has survived a severe shaking during the ノースリッジ地震 and left valuable recorded information for further study.
シンプルなローラーベアリング
Simple roller bearing is a 免震 device which is intended for protection of various building and non-building structures against potentially damaging 横方向の衝撃 of strong earthquakes.
This metallic bearing support may be adapted, with certain precautions, as a seismic isolator to skyscrapers and buildings on soft ground. Recently, it has been employed under the name of 金属ローラーベアリング for a housing complex (17 stories) in 東京、日本.31
摩擦振り子ベアリング
Friction pendulum bearing (FPB) is another name of 摩擦振り子システム (FPS). It is based on three pillars:32
関節式摩擦スライダー;
球面凹面滑り面;
横方向の変位を抑制するための密閉シリンダー。
Snapshot with the link to video clip of a シェイク-テーブル testing of FPB system supporting a rigid building model is presented at the right.
耐震設計
耐震設計 is based on authorized engineering procedures, principles and criteria meant to デザイン or 改造 structures subject to earthquake exposure.19 Those criteria are only consistent with the contemporary state of the knowledge about 地震工学構造.33 Therefore, a building design which exactly follows seismic code regulations does not guarantee safety against collapse or serious damage.34
The price of poor seismic design may be enormous. Nevertheless, seismic design has always been a 試行錯誤 process whether it was based on physical laws or on empirical knowledge of the 構造性能 of different shapes and materials.
To practice 耐震設計, seismic analysis or seismic evaluation of new and existing civil engineering projects, an エンジニア should, normally, pass examination on 耐震原理35 which, in the State of California, include:
耐震データと耐震設計基準
工学的システムの地震特性
地震力
地震解析手順
耐震ディテーリングと建設品質管理
複雑な構造システムを構築するには、36 seismic design largely uses the same relatively small number of basic structural elements (to say nothing of vibration control devices) as any non-seismic design project.
Normally, according to building codes, structures are designed to "withstand" the largest earthquake of a certain probability that is likely to occur at their location. This means the loss of life should be minimized by preventing collapse of the buildings.
Seismic design is carried out by understanding the possible 故障モード of a structure and providing the structure with appropriate 強さ, 剛性, 延性, and 構成37 to ensure those modes cannot occur.
耐震設計要件
耐震設計要件 depend on the type of the structure, locality of the project and its authorities which stipulate applicable seismic design codes and criteria.7 For instance, カリフォルニア交通局's requirements called 耐震設計基準 (SDC) and aimed at the design of new bridges in California38 incorporate an innovative seismic performance-based approach.
The most significant feature in the SDC design philosophy is a shift from a 強制-ベースの評価 of seismic demand to a 変位-ベースの評価 of demand and capacity. Thus, the newly adopted displacement approach is based on comparing the 弾性変位 demand to the 非弾性変位 capacity of the primary structural components while ensuring a minimum level of inelastic capacity at all potential plastic hinge locations.
In addition to the designed structure itself, seismic design requirements may include a 地面の安定化 underneath the structure: sometimes, heavily shaken ground breaks up which leads to collapse of the structure sitting upon it.40 The following topics should be of primary concerns: liquefaction; dynamic lateral earth pressures on retaining walls; seismic slope stability; earthquake-induced settlement.41
原子力施設 should not jeopardise their safety in case of earthquakes or other hostile external events. Therefore, their seismic design is based on criteria far more stringent than those applying to non-nuclear facilities.42 The 福島第一原発事故 and 他の原子力施設への損害 that followed the 2011 Tōhoku earthquake and tsunami have, however, drawn attention to ongoing concerns over 日本の原子力耐震設計基準 and caused many other governments to 再-彼らの核計画を評価する. Doubt has also been expressed over the seismic evaluation and design of certain other plants, including the フェッセンハイム原子力発電所 in France.
故障モード
故障モード is the manner by which an earthquake induced failure is observed. It, generally, describes the way the failure occurs. Though costly and time consuming, learning from each real earthquake failure remains a routine recipe for advancement in 耐震設計 methods. Below, some typical modes of earthquake-generated failures are presented.
The lack of 強化 coupled with poor モルタル and inadequate roof-to-wall ties can result in substantial damage to an 補強されていない組積造の建物。 ひどくひびが入った壁や傾いた壁は、最も一般的な地震による被害の一部です。 また、壁と屋根または床のダイアフラムの間で発生する可能性のある損傷も危険です。 フレーミングと壁の間の分離は、屋根と床システムの垂直サポートを危険にさらす可能性があります。
ソフトストーリー効果. Absence of adequate stiffness on the ground level caused damage to this structure. A close examination of the image reveals that the rough board siding, once covered by a レンガベニア, has been completely dismantled from the studwall. Only the 剛性 of the floor above combined with the support on the two hidden sides by continuous walls, not penetrated with large doors as on the street sides, is preventing full collapse of the structure.
土の液状化. In the cases where the soil consists of loose granular deposited materials with the tendency to develop excessive hydrostatic pore water pressure of sufficient magnitude and compact, 液化 of those loose saturated deposits may result in non-uniform 和解 and tilting of structures. This caused major damage to thousands of buildings in Niigata, Japan during the 1964年の地震.43
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地すべり落石. A 地すべり is a geological phenomenon which includes a wide range of ground movement, including 落石. Typically, the action of 重力 is the primary driving force for a landslide to occur though in this case there was another contributing factor which affected the original 斜面の安定性: the landslide required an 地震の引き金 before being released.
隣接する建物に対してドキドキ. This is a photograph of the collapsed five-story tower, St. Joseph's Seminary, カリフォルニア州ロスアルトス which resulted in one fatality. During ロマプリエータ地震, the tower pounded against the independently vibrating adjacent building behind. A possibility of pounding depends on both buildings' lateral displacements which should be accurately estimated and accounted for.
At ノースリッジ地震, the Kaiser Permanente concrete frame office building had joints completely shattered, revealing 不十分な閉じ込め鋼, which resulted in the second story collapse. In the transverse direction, composite end せん断壁, consisting of two ワイス of brick and a layer of 吹き付けコンクリート that carried the lateral load, peeled apart because of 不十分な-関係 and failed.
Poor detailing of the 強化 (lack of concrete confinement in the columns and at the beam-column joints, inadequate splice length).
Seismically weak ソフトストーリー at the first floor.
基礎効果の滑り落ち of a relatively rigid residential building structure during 1987年ホイッティアーナロウズ地震. The magnitude 5.9 earthquake pounded the Garvey West Apartment building in Monterey Park, California and shifted its 上部構造 about 10 inches to the east on its foundation.
If a superstructure is not mounted on a 免震 system, its shifting on the basement should be prevented.
強化コンクリート column burst at ノースリッジ地震 due to 不十分なせん断補強モード which allows main reinforcement to バックル outwards. The deck unseated at the ヒンジ and failed in shear. As a result, the La Cienega-Venice 地下道 section of the 10 Freeway collapsed.
ロマプリエータ地震: side view of reinforced concrete -列の失敗をサポート which triggered 上甲板は下甲板に崩壊します of the two-level Cypress viaduct of Interstate Highway 880, Oakland, CA.
擁壁の破損 at ロマプリエータ地震 in Santa Cruz Mountains area: prominent northwest-trending extensional cracks up to 12 cm (4.7 in) wide in the concrete 余水吐 to Austrian Dam, the north アバットメント.
Ground shaking triggered 土の液状化 in a subsurface layer of 砂, producing differential lateral and vertical movement in an overlying 甲羅 of unliquified sand and シルト. This 地盤破壊のモード, termed 横方向の広がりは、液状化-関連の地震被害の主な原因です。44
Severely damaged building of Agriculture Development Bank of China after 2008年四川大地震: most of the 梁と橋脚柱はせん断されています. Large diagonal cracks in masonry and veneer are due to in-plane loads while abrupt 決済 of the right end of the building should be attributed to a 埋め立て地 which may be hazardous even without any earthquake.45
津波の2倍の影響: 海の波 hydraulic プレッシャー and 浸水. Thus, インド洋地震 of December 26, 2004, with the 震源地 off the west coast of スマトラ, Indonesia, triggered a series of devastating tsunamis, killing more than 230,000 people in eleven countries by 巨大な波で周囲の沿岸コミュニティを氾濫させる up to 30 meters (100 feet) high.47
地震-耐性のある建設
地震建設 means implementation of 耐震設計 to enable building and non-building structures to live through the anticipated earthquake exposure up to the expectations and in compliance with the applicable 建築基準法.
設計と建設は密接に関連しています。 優れた技量を達成するために、メンバーとそのつながりの詳細は可能な限り単純にする必要があります。 一般的な建設と同様に、地震建設は、利用可能な建設資材を前提として、インフラストラクチャの構築、改造、または組み立てで構成されるプロセスです。48
The destabilizing action of an earthquake on constructions may be 直接 (seismic motion of the ground) or 間接 (earthquake-induced landslides, 土の液状化 and waves of tsunami).
構造物は安定しているように見えますが、地震が発生した場合は危険にすぎません。49 The crucial fact is that, for safety, earthquake-resistant construction techniques are as important as 品質管理 and using correct materials. 地震請負業者 should be 登録済み in the state/province/country of the project location (depending on local regulations), 結合 and 被保険者要出典.
To minimize possible 損失、建設プロセスは、地震が建設終了前にいつでも発生する可能性があることを念頭に置いて編成する必要があります。
Each 建設計画 requires a qualified team of professionals who understand the basic features of seismic performance of different structures as well as 施工管理.
アドビの構造
Around thirty percent of the world's population lives or works in earth-made construction.50 アドビ type of 泥レンガ is one of the oldest and most widely used building materials. The use of アドビ is very common in some of the world's most hazard-prone regions, traditionally across Latin America, Africa, Indian subcontinent and other parts of Asia, Middle East and Southern Europe.
アドビの建物は、強い地震に対して非常に脆弱であると考えられています。51 However, multiple ways of seismic strengthening of new and existing adobe buildings are available.52
アドベ建設の耐震性能を改善するための主な要因は次のとおりです。
建設の品質。
コンパクトなボックス-タイプのレイアウト。
耐震補強。53
石灰岩と砂岩の構造
石灰岩 is very common in architecture, especially in North America and Europe. Many landmarks across the world are made of limestone. Many medieval churches and castles in Europe are made of 石灰岩 and 砂岩 masonry. They are the long-lasting materials but their rather heavy weight is not beneficial for adequate seismic performance.
Application of modern technology to seismic retrofitting can enhance the survivability of unreinforced masonry structures. As an example, from 1973 to 1989, the ソルトレイクシティと郡庁舎 in ユタ was exhaustively renovated and repaired with an emphasis on preserving historical accuracy in appearance. This was done in concert with a seismic upgrade that placed the weak sandstone structure on base isolation foundation to better protect it from earthquake damage.
木造フレーム構造
木骨造 dates back thousands of years, and has been used in many parts of the world during various periods such as ancient Japan, Europe and medieval England in localities where timber was in good supply and building stone and the skills to work it were not.
The use of 木骨造 in buildings provides their complete skeletal framing which offers some structural benefits as the timber frame, if properly engineered, lends itself to better 耐震性.54
ライト-フレーム構造
ライト-フレーム構造 usually gain seismic resistance from rigid 合板 shear walls and wood structural panel ダイヤフラム.55 Special provisions for seismic load-resisting systems for all 集成材 structures requires consideration of diaphragm ratios, horizontal and vertical diaphragm shears, and コネクタ/ファスナー values. In addition, collectors, or drag struts, to distribute shear along a diaphragm length are required.
補強された組積造構造
A construction system where 鉄筋 is embedded in the モルタル目地 of 組積造 or placed in holes and that are filled with コンクリート or グラウト is called 鉄筋組積造.56 There are various practices and techniques to reinforce masonry. The most common type is the reinforced 中空ユニット組積造.
To achieve a 延性 behavior in masonry, it is necessary that the 剪断強度 of the wall is greater than the 曲げ強度.57 The effectiveness of both vertical and horizontal reinforcements depends on the type and quality of the masonry units and モルタル.
The devastating 1933年ロングビーチ地震 revealed that masonry is prone to earthquake damage, which led to the カリフォルニア州法 making masonry reinforcement mandatory across California.
鉄筋コンクリート構造物
強化コンクリート is concrete in which steel reinforcement bars (鉄筋) or 繊維 have been incorporated to strengthen a material that would otherwise be もろい. It can be used to produce ビーム, 列、床または橋。
プレストレストコンクリート is a kind of 強化コンクリート used for overcoming concrete's natural weakness in tension. It can be applied to ビーム, floors or bridges with a longer span than is practical with ordinary reinforced concrete. Prestressing 腱 (generally of high tensile steel cable or rods) are used to provide a clamping load which produces a 圧縮応力 that offsets the 引張応力 that the concrete 圧縮部材 would, otherwise, experience due to a bending load.
To prevent catastrophic collapse in response earth shaking (in the interest of life safety), a traditional reinforced concrete frame should have 延性 joints. Depending upon the methods used and the imposed seismic forces, such buildings may be immediately usable, require extensive repair, or may have to be demolished.
プレストレスト構造
プレストレスト構造 is the one whose overall 威厳, 安定 and 安全 depend, primarily, on a プレストレス. プレストレス means the intentional creation of permanent stresses in a structure for the purpose of improving its performance under various service conditions.58
プレストレスには、次の基本的なタイプがあります。
事前-圧縮（ほとんどの場合、構造の自重で）
プリテンション with high-strength embedded tendons
投稿-テンション with high-strength bonded or unbonded tendons
Today, the concept of プレストレスト構造 is widely engaged in design of 建物, underground structures, TV towers, power stations, floating storage and offshore facilities, 原子炉 vessels, and numerous kinds of 橋 systems.59
A beneficial idea of プレストレス was, apparently, familiar to the ancient Rome architects; look, e.g., at the tall 屋根裏 wall of コロッセオ working as a stabilizing device for the wall 桟橋 beneath.
鉄骨構造
鉄骨構造 are considered mostly earthquake resistant but some failures have occurred. A great number of welded スチールモーメント-抵抗フレーム buildings, which looked earthquake-proof, surprisingly experienced brittle behavior and were hazardously damaged in the 1994年ノースリッジ地震.60 After that, the 連邦緊急事態管理庁 (FEMA) initiated development of repair techniques and new design approaches to minimize damage to steel moment frame buildings in future earthquakes.61
For 構造用鋼 seismic design based on 負荷および抵抗係数の設計 (LRFD) approach, it is very important to assess ability of a structure to develop and maintain its bearing resistance in the 非弾性 range. A measure of this ability is 延性, which may be observed in a 素材自体, in a 構造要素, or to a 全体の構造.
As a consequence of ノースリッジ地震 experience, the American Institute of Steel Construction has introduced AISC 358 "Pre-Qualified Connections for Special and intermediate Steel Moment Frames." The AISC Seismic Design Provisions require that all 鋼製モーメント抵抗フレーム employ either connections contained in AISC 358, or the use of connections that have been subjected to pre-qualifying cyclic testing.62
地震損失の予測
地震損失の見積もり is usually defined as a ダメージ率 (DR) which is a ratio of the earthquake damage repair cost to the 総価値 of a building.63 予想される最大損失 (PML) is a common term used for earthquake loss estimation, but it lacks a precise definition. In 1999, ASTM E2026 'Standard Guide for the Estimation of Building Damageability in Earthquakes' was produced in order to standardize the nomenclature for seismic loss estimation, as well as establish guidelines as to the review process and qualifications of the reviewer.64
Earthquake loss estimations are also referred to as 地震リスク評価。 リスク評価プロセスには、一般に、さまざまな地動の確率と、それらの地動の下での建物の脆弱性または損傷を判断することが含まれます。 結果は、建物の交換価値のパーセントとして定義されます。65