In recent years, various kinds of aggregates are being developed for the purpose of resources recovery of solid waste. Generally, these types aggregates contain microscopic porosity in these matrixes. These aggregates show many different properties comparing with conventional artificial lightweight aggregate, such as chemical composition, manufacturing process, internal structure and external surface structure and external surface, textures. Variation of properties, density, absorption, strength, etc of porous aggregate are caused by reasons above-mentioned. According to our series studies, it was observed that properties of porous aggregate, density, absorption, strength, etc can be evaluated by porosity as common index, and porosity has a high correlation with three properties. Based on the past above investigation, this study was carried out in these experimental series. Series I : Characteristic of porous aggregate Series II : Correlation of porosity and mechanical properties of mortar and concrete containing porous aggregate. Series III : Correlation of porosity and mechanical properties of mortar and concrete containing normal aggregate and porous aggregate. Volume and radius of porosity, density, absorption, strength of aggregate in series I, volume of porosity, density, compressive strength, Young's Modulus of mortar in series II, volume of porosity, density, compressive strength, Young's Modulus of concrete in series III were measured respectively. Porosity of aggregate, mortar and concrete, density, compressive strength, and young's modulus are measured.

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In this study, the rheological characteristic of the high-fluidity concrete was evaluated by the coefficient of viscosity and the shearing yield value that was measured by using the J shaped flow test. The effects of the mix proportion factors such as the water- cement ratio, the aggregate-cement ratio, the sand percentage and the addition quantity of the super plasticizer and the segregation agent on the rheological constants of the high-fluidity concrete were investigated. It was clarified that the shearing yield value of high-fluidity concrete can be made low by setting water-cement ratio and the sand percentage to the proper value, by setting the aggregate-cement ratio small, and the viscosity of high-fluidity concrete can be adjusted with the addition quantity of the segregation agent.

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Although laser is widely used for cutting, welding and surface treating metals, application of the laser for processing inorganic architectural materials is quite rare. In this study, the feasibility of using laser energy to form glass layers on mortar panels with zeolite aggregate was assessed. The effects of mix composition and laser irradiation parameters on the characteristics of the glass layer and on the flexural strength of zeolite mortar panels were investigated. It was found that the optimum mix composition and laser irradiation parameters for obtaining panels with high flexural strength and stable glass layers were as follows : zeolite particle size = 0.6 to 1.2 mm, W/(C+Z) = 25 to 30 %, cement/zeolite mass ratio = 1 : 2 to 1 : 3, Laser power = 1kW, beam diameter = 200 mm and work travel speed = 750 mm/min.

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We tried to establish the quantitative value of tiled walls' accuracy of finishing by using CI, which is the quantitative value corresponding to the conspicuousness of the irregularity of a tile. Human perception on tiled walls' accuracy is influenced by not only a tile whose CI is biggest of the wall but also other tiles whose CI are rather big. So, we prescribed the measuring area according to the visual field, and measured CI of each tile from there. By weighting and adding them in big order, we established 'AF' as the quantitative value of tiled walls' accuracy of finishing.

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The purpose of this study is to present the relative evaluation method of unevenness of floors from a viewpoint of trouble to human caused by vibration on casters. First, we carried out sensory tests to make evaluation scales of vibration on casters such as wheelchair and stretcher. Next, we developed the specialized caster. This caster could detect the acceleration on casters caused by unevenness of floors, corresponded to evaluation scales. Finally, we presented the relative evaluation method of unevenness of floors, dealing with maximum amplitude of acceleration detected by the specialized caster.

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The outline of this study is as follows : The first, sensory tests were carried out to make psychological scales of suitability, fatigue and effect to keep the physical fitness in walking on "Loose-Surface". And it was cleared that there were intimate relations among these psychological scales. The second, biomechanical and physiological parameters in walking were investigated using force plate, electromyogram and heart rate monitor. As a result, it was cleared that "Loose-Surface" wasn't suitable for walking and was fatigable, but it was effective to keep the physical fitness. Also it will be careful to use "Loose-Surface" for physically handicapped.

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1序 多数の破壊モードを含む系の破壊確率の正確な推定は,一般に困難である.そのために,実用上,信頼度の近似点推定や区間推定が行われている.並列系の信頼度の有効な区間推定式は,著者等の知る限り,今迄の所存在しない.直列系の区間推定式としては,Ditlevsenの2次式,Ramachandran,Fengの3次式,およびGreigの高次式がある.これらは総て相関係数に無関係に成立するので,無条件の区間推定式と呼ぶことにする.本論では,並列系の高次式と一般系に対する相関を考慮した区間推定式を導いて,推定幅を狭める.2既存法 2.1並列系 破壊確率の無条件の1次区間は,(5)式で表される.基本破壊モードの相関係数が総て正の場合は,(6)式になる.相関を考慮しているので,条件付き区間と呼ぶことにする.2.2直列系 破壊確率の無条件の(1〜3)次区間は,(8),(14)および(15)式で表される.(16)式は,正の相関に対する1次区間である.3提案法 一般系の破壊は,基本破壊事象の積の和で表される.この和事象は,排反な積事象の和に書き直すことができる.従って,系信頼度の評価には,積事象の確率計算が必要不可欠である.破壊は,共通の原因により起こることが多い.その場合の基本破壊モード間の相関係数は,正となる.本論では,正の相関係数を持つ系の信頼度の推定を重点的に行う.しかし,負の相関を含む系も考究対象とする.3.1並列系 無条件の区間 ; 系の信頼度P(F^^~_s)の区間を2で述べた直列系の式で求める.これを式P(F^^~_s)=1-P(F_s)に代入すれば,無条件の区間が得られる.しかし,この式は複雑であるから,これよりも単純な(23),(24)式を誘導した.更に高次の式は,破壊条件数が増える以外同じである.条件付き区間 ; 正の相関を持つ積事象の下限値は,総ての基本破壊事象が独立であると仮定して求める.上限値は,P(F^^~_s)を独立の仮定に基づいて評価し,式P(F_s)=1-P(F^^~_s)に代入すれば求まる.結局,2,3次区間は,それぞれ,(28),(29)式で表される.総ての相関係数が負の場合の上限値は,条件付き区間(28),(29)式の下限値である.下限値は,無条件の区間の下限値である.正と負の相関係数を同時に含む系の上限値は,正と負の相関係数を,それぞれ,1と0と見なして計算する.下限値は,正と負の相関係数を,それぞれ,0と-1と見なして計算する.3.2直列系 無条件の区間 ; 破壊確率の区間としては,2で述べた既存式があるが,複雑である.(23),(24)式に基づく単純な(32),(33)式を誘導した.条件付き区間 ; 余事象の確率P(F^^~_s)を(23),(24)式で計算して,式P(F_s)=1-P(F^^~_s)に代入すれば,(34),(35)式の破壊確率の区間がえられる.高信頼度の系では,この式による確率が1に近くなるので,計算が難しくなる.その場合は,(36),(37)式を用いればよい.負の相関を含む場合の下限値は,正と負の相関係数を,それぞれ,1と0と見なして計算すれば求められる.また,上限値は,正と負の相関係数を,それぞれ,0と-1と見なして計算すればえられる.4例題 [例題1] n(n=1,2,…100)個の基本破壊事象を含む並列系がある.その基本事象の破壊確率は,φ(-0.5)である.事象間の相関係数ρ_<ij>は,総て等しく0.7である.(1〜10)次の区間推定を行う.系信頼性指標β_sと推定区間を図-1に示す.β_sは,lognにほぼ比例している.[例題2] 例題1と同じ問題で,n=50とし,pを変えた場合の区間推定幅を調べる.結果を図-2に示す.推定幅は,相関が高いほど狭まる.例題1と2より,同程度の信頼度を持つ基本破壊事象が多数あり,それら総てが互いに低い相関を持つ系では,高次の区間推定が必要になることが分かる.[例題3] n個の基本破壊事象を含む直列系がある.β_i=β=3, p_<ij>=p=0.7, n=(1,2,…50)とし,(1〜10)次の無条件と条件付きの区間を比較する.結果を,図-3と図-4に示す.両図を比べて見ると,2次以上の条件付き区間の幅は,無条件の区間に比べて明らかに狭い.[例題4] 例題3と同じ問題で,n=50とし,pの変化に対する推定幅を調べる.結果を図-6と図-7に示す.両図を比較すると,2次以上の条件付き区間の幅は,無条件の区間に比べて明らかに狭いことが分かる.[例題5] 文献-5の建築構造物の例題をとり上げる.(42)式の性能関数を持つ構造系がある.基礎確率変数は,互いに独立な標準正規分布である.係数は,(43)式を満足するように,(45)式の値を仮定する.β=3の場合の,条件付きと無条件の破壊確率の推定幅を比較する.表-1は,(n=10,20,30)に対する推定幅を系の破壊確率で割った値である.2-4次の条件付き区間の幅は,無条件の幅に比べて,はるかに狭いことが分かる.5結論 並列系の破壊確率の狭い区間推定を行うために,高次式を導いた.また,基本破壊モード間の相関係数を考慮し,総ての系に適用できる区間推定式を提案した.最後に,破壊確率の推定幅の既存法との比較と高次解による推定幅の減少を,例題を通じて調べ,本法の有効性を示した.

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As a building becomes higher and more slender, the hysteretic damper is often installed for mitigation of oscillations. However in the case that the oncoming wind velocity almost reaches the critical range of the onset of aeroelastically unstable phenomena, we encounter the unsolved trade-off problem such that a damping performance of the building surely increases, but the natural frequency tends to shift lower and resonant velocity becomes lower. So we carry out the wind tunnel experiment in order to estimate the across wind oscillations of a tall building with hysteretic damper, which is placed in the atmospheric turbulent boundary layer. We also estimate a hysteretic damping performance by investigating the relation between the static load and the deformation of a building model. Finally we compare the inelastic response under the hysteretic damping conditions with the elastic response under the equivalent viscous damping conditions. On the basis of their relation, the performance of hysteretic damper on a tall building is discussed.

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The objective of this study is to investigate the seismic performance of a structure supported on pile foundation. Pile foundation response during earthquake is strongly affected by nonlinear interaction of soil and superstructure. Earthquake response analyses are conducted to clarify the effect of soil-pile foundation-superstructure system to the performance of pile foundation. Pile responses are evaluated using the nonlinear relationship between bending moment and curvature dependent on the axial force. Performance of pile foundation is discussed on the basis of the curvature of piles and the displacement at the pile head.

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In this paper, the characteristics of horizontal complex stiffness of the embedded foundation are investigated by applying the three-dimensional thin layer element method. For an embedded foundation - boundary soil zone - outer soil zone system model, the non-linearity of the soils within the boundary soil zone around the embedded foundation are analyzed by the use of the equivalent linearization method. The relationships between the strain, shear rigidity and damping constants of the soil are evaluated by the use of the Ohsaki-Hara Model.

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The mixed assumption theory can propose static and dynamic theory which satisfy the boundary conditions of upper and lower surfaces of the plate. In this paper, we formulate general higher-order theory of plates under assumption of displacement and stress components of the plate thickness distribution by using the dynamic variation principle of the mixing type which made specialized the basis of Hu-Washizu. This equation was examined through static and dynamic solution example, and as well was studied the influence given to the solution precision if it satisfies or not boundary condition of upper and lower surfaces of the plate.

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Structures are made by assembling several blocks that we can handle by construction machines and ourselves. Arrangement of the blocks is very important in the construction planning. The arrangement is made by trial and error, considering many conditions. Therefore the work of the planning is very difficult It is also difficult to judge fitness of a decided arrangement by a usual planning method. In this paper, two analytical methods using genetic algorithms are introduced into two optimum problems of dividing structures into blocks under construction : divisions of plate structures and truss structures using panntadome system. The results of analytical examples verify that the proposed analysis can give an optimum arrangement of blocks and could plan the arrangement easily.

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Solution form proposed in this paper derived by using Moore-Penrose generalized inverse based on the displacement method can apply even to the problems on the singularity of the stiffness matrix. By solving the elastic and the rigid-body deformations of retractable structure, the exact equivalent linear treatment of the shape-finding and the stress analyses of tension structure such as cable structure, and also investigating the bifurcation phenomena of a shallow arch structure, the advantage of that there is the condition for the existence of a solution in the solution form itself is illustratively presented with the theoretical proof.

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This paper continues from the previous thesis (Part 1). It presented experimental result of model earthquake-proof piles guarded with short outer sheath pile and also a calculation method for the pile system of this type. In this study, we calculate the horizontal behavior of earthquake-proof pile composed with a PHC-pile (main pile) and a steel pile (outer pile). It takes into account the non-linear property of bending rigidity of both piles subjected to the vertical load in an earthquake. From these results, it was found that the seismic horizontal capacity of the earthquake-proof pile in both short time and ultimate state could increase remarkably in comparison with an isolated main pile, even if the outer sheath pile length is set up comparatively short.

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In the top-down construction method, structural steel columns are embedded in cast-in-place concrete pile. Axial force from steel column to concrete pile is transmitted by the following resistances, bond resistance between steel column and concrete pile, shear resistance of stud connectors and bearing resistance at the end of the steel column. In this paper, 24 static loading tests were carried out. The main parameters were embedded length, section of steel column and the number of stud connectors. Based on these test result, ultimate strength of concrete pile head is evaluated as the sum of resistance strengths modulated by effective factors.

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In this paper, the relation between the wall-length ratio of Japanese wooden houses and the ultimate horizontal resistant force considering the stiffness of both floor and non-structural walls is discussed. The analytical Model has the restoring force characteristic composed of the floor, bracing bearing walls and non-structural plaster board walls. The results may be summarized as follows : The wall-length ratio considering both structural walls and non-structural walls is nearly equal to the wall-length ratio considering only structural walls. The lower limit of the ultimate horizontal resistant force is estimated using the wall-length ratio considering only structural walls.

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Lateral buckling is one of the most important limit states for glue-laminated wood beams with deep depth and long span. The purpose of this paper is to present design formulae for lateral buckling strengths of glue-laminated wood beams. Lateral buckling tests for three sectional types of laminated wood beams are conducted. Based on the test results, it is shown that the lateral buckling strengths agree well with the strengths based on the classical elastic theory for beams. The variations of the lateral buckling strengths are presented based on the first-order second-moment method for the calculation of resistance factors of partial safety factor formats.

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1.序 鋼管横補強柱の設計を合理的に行うためには以下の問題点を明らかにする必要がある。1)高軸力を受ける鋼管横補強柱の耐震性能2)大量の主筋を有する鋼管横補強柱の耐震性能3)鋼管横補強柱の耐震性能に及ぼす鋼管板厚の影響4)鋼管横補強柱の耐震性能に及ぼすせん断スパン比a/Dの影響5)鋼管横補強柱の終局耐力および変形能力の評価法 第1と第2報においてはa/Dが2.0の柱を用いて、上述した問題の内、其々1)と2)及び3)の問題について検討した。本報においては4)の問題を取上げ、14体の試験体を用いて実験的に検討する。2.せん断スパン比1.0の鋼管横補強柱の実験 2.1実験概要 通常の形状比を有する柱の場合、曲げ性状が支配的である事から、鋼管の拘束効果は曲げ圧福部の横方向膨らみを拘束する事により生じる。このことについては、本報第2報において明らかにしている。しかしながら、短柱になるとせん断性状が支配的となり、柱の破壊現象が柱全長に渡って生じ易くなるため、鋼管は柱のせん断ひが割れの進展による横方向膨らみを拘束する必要がある。以上より、鋼管の拘束効果は柱のa/Dによって異なる事が予想される。鋼管横補強柱の耐震性能に及ぼすa/Dの影響を明らかにするために、250mm角の正方形柱10体(以下2Dシリーズと呼ぶ)を製作し、一定軸力下における繰返し曲げせん断実験を行った。主筋比は本論第2報に用いた試験体と同じで、2.44%である。試験体の形伏および配筋詳細を、図1に示す。2Dシリーズ実験における実験変数は、鋼管板厚と鋼管の外幅の比である鋼管幅厚比(5種類、B/t=28〜118)と軸力比(n=0.33, 0.50, 0.67)である。表1に、2Dシリーズの試験体の性質を、耐力・変形に関する主な実験および解析結果とともに示す。各試験体のコンクリート圧縮強度を表1に示す。鋼管の力学的性質については第2報を参照されたい。試験体には逆対称の繰返し水平変形を与え、加力・測定方法は前報と同じである。2.2実験結果 図2に2Dシリーズ試験体のひび割れ図を示す。軸力比nが0.33の試験体は、鋼管板厚には関係なくせん断ひび割れが支配的である。しかしながら、nが0.50より大きくなると、せん断ひび割れよりもむしろ縦割裂ひび割れが顕著となる。実験より得られた水平力Vと部材角Rの関係、軸方向伸縮量δとRの関係を図3に示す。実験中に観察された最大水平力V_<max>とその時の部材角R_<max>、水平耐力が最大耐力の95%に低下した時の限界部材角R_u, の値を表1に示している。V-R関係図には、耐力計算値を示す3本の線が示されている。■を結んだ線は著者等により提案された曲げ耐力計算値V_<mu>を、□を結んだ線はACI規準による曲げ耐力計算値V_<un>を、点線は修正大野・荒川式によるせん断耐力計算値V_<su>を示している。著者等の曲げ耐力算定式は、鋼管の拘束効果のみならずスタッブの拘束による耐力上昇も考慮に入れている。nが0.33の短柱は鋼管板厚が厚くなるほど靭性に富む挙動を示す。鋼管幅厚比が大きい(117、82、60)場合は、部材角が大きく(それぞれ、0.02rad,0.025rad,0.035rad)なると耐力劣化が顕著になるが、軸力支持能力は最後まで保持していた。鋼管の幅厚比が小さい(43、28)場合は、拘束効果を考慮に入れた曲げ耐力には達していないが、大変形時まで非常に安定した挙動を示す。なお、すべての試験体において、主筋が引張り圧縮とも最大耐力時あるいはそれ以前に降伏ひずみに達していた。以上のことから試験体の破壊モードは、曲げ降伏先行後のせん断破壊であるということが出来る。一方、nが0.50以上の高軸力を受ける短柱の場合は、せん断圧縮破壊を生じた。幅厚比が43以上の鋼管で横補強された柱の場合は、耐力の低下は急激で、軸方向縮みの累積を伴った。一方、幅厚比43以下の鋼管を用いれば、拘束効果を考慮に入れた曲げ耐力を発揮するまでには至らないが、変形能力及び終局耐力を顕著に上昇させることが出来た。柱の主筋は引張降伏ひずみに達することはなかった。また、表1より分かるように、修正大野・荒川式は、鋼管横補強柱のせん断耐力実験値の下限値を比較的精度よく算定できる。3.せん断スパン比1.5の鋼管横補強柱の実験 a/Dが1.5の試験体4体(3Dシリーズと呼ぶ)について、2Dシリーズと同様な実験を行った、実験変数は鋼管板厚のみで、nはすべて0.33の一定値とした。材料の性質等は前節のそれと同じである。図4に3Dシリーズ試験体のひび割れ図を示す。曲げひび割れが支配的で、ひび割れは材端において長さ1.0Dより小さい範囲に生じている。α/Dが2.0の試験体の場合と同様に、損傷を受けている領域の長さは、鋼管板厚が厚くなるほど短くなる。実験より得られたV-Rとδ-R関係を図5に示す。実線および破線の意味は図3のそれと同じである。図5より明らかなように、全試験体ともR=0.04radに至るまで安定した挙動を示しており、曲げ耐力V_<mu>を発揮している。T3・33・3D試験体のみはR=0.045rad時に耐力劣化をおこしているが、これは鋼管溶接部にキレツが生じたためである。以上述べたことより、a-Dが1.5でnが0.33の場合は、幅厚比が82の薄肉鋼管による横補強でも、柱の破壊モードは曲げ破壊となり柱に充分な変形能力を与えることが出来る。4.せん断スパン比の影響に関する考察 鋼管横補強柱の耐震性能に及ぼすa/Dの影響を評価するために、V-R関係の正荷重時における包絡線の比較を、nが0.33の場合について図6に示す。比較のためa/Dが2.0の試験体の実験結果についても示している。図6から分るように、a/Dが1.0の場合は、nがそれほど大きくない場合でも、柱に充分な靭性を期待するためには幅厚比が43以下の鋼管で横補強する必要がある。一方、a/Dが1.5より大きい柱の場合は、幅厚比が82の薄肉鋼管による横補強でも、充分な靭性を期待することが出来る。a/Dの影響は図7においても、より顕著に見ることが出来る。図7は、前節で述べた限界部材角R_uの実験値と幅厚比の関係を示したものである、図7aより、コンクリートの圧縮強度が30MPaでnが0.33の柱の場合、a/Dが1.0の短往のR_uは、1.5と2.0の柱に比較すると、いずれの幅厚比の場合も、平均的にみて0.011rad程度小さいが、a/Dが1.5と2.0の柱ではR_uの値は殆ど変らないことが分る。nが0.67の場合についても同様のことが言える(図7b参照)。5.結論 本研究においては、a/Dが1.0と1.5の柱試験体14体について、繰返し曲げせん断実験を行い、以下の結論が得られた。1)本研究の実験条件の下では、a/Dが1.0の短柱のせん断破壊を鋼管横補強により完全に防ぐことは困難であったが、厚肉の鋼管を用いれば短柱の靭性を改善することはできた。靭性改善のために必要な鋼管の幅厚比は軸力比nに依存し、nが0.33と0.67の場合の必要幅厚比はそれぞれ43、28であった。2)鋼管横補強柱の耐震性能に及ぼすa/Dの影響は、破壊モードの違う場合に顕著となる。a/Dが1.5以上の鋼管横補強柱は、いずれも曲げ破壊であったので、a/Dの影響は非常に小さい、a/Dが1.0の柱は、幅厚比が28の厚肉鋼管を用いてもせん断破壊を防ぐことは出来なかったので、a/Dが1.5以上の曲げ破壊する柱に比較すると、他の条件が同じであれば柱のR_uは約0.01rad程小さくなる。3)せん断破壊する鋼管横補強柱のせん断耐力下限値は、修正大野・荒川式により推定できる。せん断耐力実験値と計算値の比は平均値が1.12、標準偏差が0.07であった。4)曲げ破壊する鋼管横補強柱の耐力は、著者等により提案された拘束効果を考慮に入れた算定式により精度よく推定できる。a/Dが1.5の試験体の耐力実験値と計算値の比は平均値が1.02、標準偏差が0.03であった。従って、著者等により提案された曲げ破壊する柱の水平耐力算定式と修正大野・荒川式によるせん断耐力算定式を用いれば鋼管横補強柱の破壊モードの推定が可能となる。

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Beam specimens of lapped splice bars with high-strength concrete were tested to determine the bond splitting strength at the critical section of a beam, under shear-bending stresses for 10 specimens and under pure bending stress for 3 specimens. Shear-bending load was applied to the longitudinal lapped splice bars of a beam of high-strength concrete until they fracture in side-split mode. The main variables tested are lapped splice length and transverse reinforcement ratio. The bond splitting strength of shear-bending test specimens is larger than that of pure bending test specimens. The existing equation of bond splitting strength, which takes into account of shear-bending stress, was proved to give satisfactory estimation of the bond splitting strength of lapped splices in the shear-bending test specimens.

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FEM analysis are performed to investigate the local behaviors of tubular steel towers reinforced by ring-stiffeners under two different loading conditions. The effectiveness of these results are evaluated through empirical studies using real-scaled models together with the preceding results regarding the tubular steels stiffened by both of ring-stiffeners and gusset plates. The derived conclusions are : (1) the effects of the axial forces on the yield strength of the stiffened steels are investigated. (2) the yield strength of a ring stiffener increaces under loads in a single direction while it decreases when loads are in multiple directions. (3) the stress distribution in ring-stifferners is able to be effectively evaluated by the proposed method.

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In this paper, evaluation of seismic performance of moment resisting steel frame using the shaking table test is discussed. Specimens are moment resisting steel frame with or without use of the buckling resisting brace. Three different type waves (El Centro, Hachinohe and Kobe) are inputted in the shaking table with two levels (level 1 = 25kine, level 2 =50kine). As a result of the test, we have confirmed that moment resisting steel frame with the buckling resistant brace can greatly reduce both the deformation angle and maximum strain at the edge of the beams in their mainframe. It was also shown that a capacity for energy absorption and fatigue properties of the damper decreases when set within the frame. However, the buckling resistant brace within the frame has enough capacity to resist level 2 earthquakes more than 30 times.

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Many fractures in beam-to-column connections of steel framed structures occurred in Hyogo-ken Nanbu Earthquake. In this paper, we notice on the influence of composite beams as a factor of such fractures, and investigate the deformation capacity of composite beams by a series of experiment. Main conclusions are as follows. (1) The deformation capacity of composite beams is remarkably lower than steel beams without slabs. (2) Section properties and loading histories have little influence on the deformation capacity of composite beams. (3) When composite beams are subjected to a positive bending moment, following phenomena are observed : a) Strain is concentrated to lower flanges. b) Plastic deformation is concentrated to narrow area near the beam-to-column connections. These are the factors which reduce the deformation capacity of composite beams.

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The 1995 Hyogoken-Nanbu Earthquake gave us a lesson that brittle fracture of beam connections may not necessarily knock down steel frames of buildings. This experimental study is purposed to clarify the reasons why steel frames could stand after such serious damage in beams during the earthquake. It was found that the most promising factor which could support the buildings after beam fracture is the backup of reinforced concrete slabs connected to steel beams with studs. Even after complete fracture of beam sections connected to a column, the beam ends could carry negative bending moment by a couple of tensile force in reinforcing bars in the slab and compressive force in the beam's lower flange which has a post-fracture contact with the column.

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The previous paper proposed a seismic design procedure to estimate the ductility demanded of beams in steel frames that sustain overall collapse mechanisms. In this paper, a method is presented to predict a collapse mechanism that can form with the greatest probability in a frame structure under severe earthquake excitations, and the amplification factor of the ductility demand is determined based on the predicted collapse mechanism. Seismic responses of steel frames sustaining various collapse mechanisms are examined numerically. The results of the proposed method favor the overestimation of ductility demand for frames sustaining partial collapse mechanisms in a few stories but the approximation of the upper limit of numerical results.

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In a recent study, it was clear that the beam with large web slenderness has enough plastic deformation capacity for seismic design. But the large deformation behavior and the collapse mechanism of these beams have not been cleared. In this study, the collapse mode and that deciding the maximum load are investigated by experiment study and numerical analysis. As a results, it is clear that the ratio of the shear strength to bending strength of the beam is very important factor for the plastic deformation behavior. And the plastic deformation capacity of the beam is estimated by using the ratio.

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The fracture of tubes following cyclic local buckling should be one of the important failure modes with regard to the deformation capacity of concrete-filled tubular (CFT) beam-columns under severe earthquakes, so that such members under a loading condition of low-averaged but widely-fluctuating axial loading should frequently fail by this failure mode. However, the failure mode has not been fully investigated. From this point of view, the experiment was conducted on the CFT beam-columns under cyclic axial loads and horizontal loads. The experiment showed that (1) the failure mode of every specimen was the fracture of a tube after local buckling ; and (2) the fracture could be successfully predicted by the authors' fracture prediction formula.

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Seismic response and damage of concrete filled steel tube frame (CFT frame) are investigated in relation with the column over design factor (COF) of it. The numerical analysis method to predict the damage of CFT frame under strong ground motion is obtained by introducing the damage factors of steel tube crack and local buckling of CFT column. By the use of the presented analysis method the seismic responses of CFT frame subjected to the ground motions recorded in Kobe (1995) and El Centre (1940) have been calculated and the damage factors of CFT frame to collapse dynamically are obtained quantitatively. From the results it is shown that the calculated damage factors of CFT frame are closely related to the value of COF and COF=2.0 is proposed as the critical value of COF in the earthquake resistant design of multi-story CFT frame.

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A finite element model for bolted beam joints and a way to incorporate it into an existing FEM frame analysis have been developed to find the detailed histories of stress distribution both inside and outside the joints of frames under increasing member temperatures. Observing a series of computational results, it is found that the ultimate temperature can be approximated primarily by the simple plastic theory, whether a heated frame has bolted beam joints or not. It is also found that the residual post-peak shear strengths of bolts, whose existence seems expectable under elevated temperatures, help the ultimate temperature of a frame with bolted beam joints to increase to a significant extent.

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This paper is concerned with the identification analysis of structural damage detection on the unit-linked floating structure model based on fluid-coupled free vibration equation and filtering algorithm. The problem of structural damage detection is formulated as an inverse problem in structural engineering. The formulated inverse problem must be analyzed under the consideration of stochastic properties on the responses of system because the observations of the system are usually measured in the presence of noise. The filtering algorithm has been well known as the solution method that is able to consider stochastic properties. In this paper two kinds of filtering algorithm, namely the extended Kalman filtering algorithm and new filtering algorithm based on the projection filter, are employed in the identification analysis. The coupled natural frequencies used as the observations and stochastic properties of system responses adopted the data obtained by experimental modal analysis.

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