電子機器のに当たっては、コストミニマムで耐用年数を満たすことが要求されている。ところが、最近の高密度実装化と地球環境調和型の要求される中で、設計者がに当たって重要なことがらを見落としている。これらの問題点を指摘し、設計者が今後のにこれらの問題点を考慮して設計するように望まれる。

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Some partial factors have been proposed to introduce the level-one reliability-based design method for port facilities. However, any particular partial factor for Sand-Compaction-Pile (SCP) method has not been proposed.
In order to establish the partial factors for circular arc slip failure mode of port facilities including SCP improved ground, reliability indices against that failure mode were checked. In this analysis, the probability distribution of friction coefficient of SCP on the basis of SPT-N records is identified. As the result of the analysis, it is confirmed that the safety level by the present design method is higher than that of the minimum expected total cost, and that some parameters, such as SCP-friction coefficient, has a significant impact on stability. On the basis of the sensitivity factors of parameters, the partial factors designed for facilities including SCP improved ground are proposed.

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構造物の設計法は、従来の許容応力度法に基づいた仕様規定型設計体系からに基づいた性能規定型設計体系に移行している。しかしながら、構造物の中でも地盤構造物への性能設計/の導入は、他のコンクリート構造物や鋼構造物と比較して遅れているのが現状である。これは、地盤材料が持つ本来的な不確定性および設計手法・解析手法の予測精度の低さに起因するものと考えられる。を実現することは、より安全で経済的な構造物を提供することに繋がるため、上記の問題に対処し、地盤構造物の性能設計/手法を開発することは喫緊の課題となっている。本研究では、データ同化手法の中でも非線形問題に容易に適用可能な粒子フィルタに着目し、その土構造物のへの適用性について検証する。はじめに、粒子フィルタを用いた地盤構造物の手法を提案し、その概要を示す。その後、土構造物の建設を模擬した数値シミュレーションを対象に、提案手法の適用性について議論する。

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は新しい技術分野である。 ばね工業では信頼性工学の適用はまだ信頼性試験の段階に止まっていて, についての研究資料は少ない。 本研究では長年の信頼性研究にもとづいて, 応力分布と強度分布の干渉理論を圧縮コイルばねに応用し, その公式を導いた。 特に, ショットピーニングやホットセッチングなどの製造工程が, 製品の寿命に及ぼす影響を設計パラメタとしてはじめて導入した。 また, 設計の信頼性と製品の材料強度及び製造手段レベルとの関係を定式化し, ばねのの理論体系の基礎を確立した。

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本研究では, 全国のケーソン式混成堤の設計資料より収集した33ケースを用い, 森屋ら (2003) の提案する設計波 (50年確率波) 1波による滑動量に基づく破壊確率と, 下迫・高橋 (1998) の提案する設計供用期間中の来襲波群による累積滑動量に基づく破壊確率との比較を行った.その結果, 設計供用期間中の滑動安全性に対する波浪の極値分布形の影響は大きく, 前者を制御しても後者としては危険な設計になることがわかった.次に波浪の極値分布形等の設計条件によって前者の目標値を修正し, 森屋ら (2003) によるレベル1法に適用する手法を提案し, 簡易なレベル1設計法でありながら, 設計供用期間中の滑動安全性を制御対象とした設計が可能となることを示した.

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Level 2 performance based design, which considers the probability of design values as normal or lognormal distribution, is introduced for coastal pumping stations. Considering inundation risk, the outer forces are assumed to be the increase of water levels in drainage canals caused by inflow, and counter forces are assumed to be the decrease of water levels in drainage canals caused by pumping discharge and drainage gate discharge. Design rainfall is modeled as lognormal distribution based on data from the Saga Meteorological station. Design tide levels are modeled as the sum of residuals of high tides caused by typhoons and astronomic tides at Oura. Based on a Monte Caro simulation for 100,000 years, the maximum water level data in drainage canals are calculated to evaluate performance.

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It is necessary to determine the target safety level in order to introduce level-1 reliability-based design method. We discussed the target safety level against the circular arc slip failure of breakwaters under ordinal condition, for which the effect of the wave forces are not taken into account. Based on the comparison of average safety level under the current design method with that of the minimum expected total cost including the economic loss, it is shown that safety level by the current design method is very high. The partial factors for level-1 reliability-based design method are proposed.

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This paper describes the level-1 reliability-based design method in view of sliding deformation for caisson-type breakwaters with wave dissipating works. Reliability analysis based on FORM (First-Order Reliability Method) was conducted by using 37 cases of breakwaters constructed all over Japan. In this study, the model proposed by Moriya et al. for calculating sliding deformation was applied to performance function, 10 or 30cm was used for allowable sliding deformation and 8.2×10-3 was used for target failure probability. As a result of this analysis, partial safety factors were calibrated appropriately. Moreover, it was shown that rational and economical design would be possible by using this design method compared with the present design method based on factor of safety.

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FORM is frequently used while SORM is not because FORM is easy to be implemented. Considering the accuracy, however, reliability index calculated by FORM might not be accurate enough in case the performance function is strongly nonlinear. Taking the performance function for the external stability of breakwaters as an example, although that of the sliding failure mode is nonlinear, reliability indices was evaluated by FORM in the previous study. In this study, taking the sliding failure of gravity-type breakwaters (two structural types: caisson-type composite breakwaters, breakwaters covered with wave-dissipating blocks) as the subject of research, we executed the reliability analysis by using FORM and SORM. From comparison of the reliability index obtained by FORM and SORM, it was made clear that the reliability index by FORM is accurate enough in general.

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It is important to specify most dominant design parameters affecting safety of structures and to improve estimated accuracy of them in order to promote construction cost reduction through the reliability-based design. In this study, the dominant parameters for stability against sliding, overturning, and foundation failure of caisson-type breakwaters are specified by using safety index and sensitivity factor with FORM (First-Order Reliability Method). Moreover, correlations among failure modes in present design sections were described.

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　防波堤の滑動に対する性能照査において、モンテカルロシミュレーションを用いて滑動量の確率分布を計算し滑動量による制御を行う方法か提案されているが、計算時間の問題が無視できないため実務上はより簡易な方法で計算できることが望まれている。そこで本研究は、滑動量の確率分布と破壊確率を簡易に計算するために、防波堤前面波の確率分布を既存の確率分布関数を用いて定式化することを目的とした。その結果、防波堤前面波の確率分布において、滑動の発生する範囲である確率分布の右側すそ野部分は、砕波の発生条件に応じてワイブル分布もしくは極値III型分布によって近似でき、近似した分布関数は防波堤の設計パラメータを用いた重回帰式により定式化できることを明らかにした。

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While the research on the deformation-based reliability design of composite breakwaters has been carried out for many years, sliding phenomena including rocking motion have not been carefully examined. In this study, hydraulic model experiments were conducted in a wave flume to investigate the characteristics of wave forces and sliding phenomena of the breakwater caisson. The difference of static friction coefficient and dynamic one should be considered in order to improve the estimation accuracy. Numerical simulation (CADMAS-SURF) can reproduce the time series of wave forces more precisely compared to the practical model used in the current calculation method, especially in deep water area.

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防波堤の滑動破壊モードを対象に, 限界沖波波高の考え方を導入したモンテカルロシミュレーションを実施し, 損傷確率の算定方法について検討を行った. 設定した15ケースの断面について損傷確率を算定し, 従来の安全率との比較を行った. さらに, モンテカルロシミュレーション結果から, 滑動量を目的変数とした重回帰分析を行い感度をもとめ, 部分安全係数を算定した. そして, いくつかの設置水深に対して, 算定した部分安全係数を用いた防波堤の試設計を行い, その適用性を確認した. その結果, 部分安全係数から求めた堤体幅の安全性は異なる設置水深に対しても比較的安定しており, 合理的な設計となることがわかった.

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The partial factors of the performance verification equation for the ultimate limit state of RC structural member subjected to bending moment and axial force are studied based on the reliability-based design. The first-and second order reliability methods with the importance sampling update are used for the reliability analysis. The influence of the deviation of the coefficient of variations (COV) of four design variables on the partial factors is studied for different eccentricities of the RC section. Further, methods for the identification of target reliability levels and other important issues are discussed. The procedure to determine the partial factors demonstrated in this study can be applicable for other performance verification equations stipulated in the JSCE' Specifications and other design standards.

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The reliability-based design method is the standard design method for the technical codes for port facilities. Determination of target failure probability is very important on the reliability-based design.
In this study, the sliding failure of the caisson type breakwater (composite type breakwater and breakwater covered with wave-dissipating blocks) is treated in view of sliding displacement. First, survey of the latest design wave condition including extreme probability condition is conducted. Characteristic of design wave condition in each area is analyzed. Next, failure probability for caisson type breakwaters designed by conventional design method is estimated in view of sliding displacement. Finally, target failure probability is optimized in order to apply the reliability-based design to practical design using the latest design wave condition.

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This study develops the level-1 reliability-based design method for breakwaters covered with wave-dissipating blocks based on the sliding deformation in regard of wave extreme value distribution. We compared the failure probability based on the sliding deformation caused by single highest wave and that based on the cumulative sliding deformation during design service period (abbreviated as level-3 method). As a result of this study, we proposed the method to deteminie the target rcliability index for the level-1 design method by using the design conditions such as wave extreme value distribution and so on. Moreover, we showed that the proposed method is almost equivalent to the level-3 method in terms of reliability.

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本研究では, ケーソン式混成堤の破壊滑動量を制御対象としたレベル1法の構築を行った. 全国の設計資料より選んだ35ケースを用いて, 谷本ら (1996) による波力の時系列モデルを外力とした滑動の運動方程式を2回積分して求めた滑動量とほぼ同様の滑動量が得られる簡易滑動量算定モデルを構築した. 次いで, 滑動限界値を30cm, 破壊確率の目標値を8.2×10^-2と設定し, 破壊確率の目標値に対する分散が最小になるように部分安全係数を設定した. 構築したレベル1法は, 安全率に基づく設計法と比較して, 堤体幅は平均0.7倍となり, 合理的かつ経済的な設計が可能であることを示した.

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