Japan Structural. Consultants Association (JSCA) developed a performance based design code (JSCA Code) where a seismic performance gradation system has been prepared. In JSCA Code, boundaries of performance grades are given by numerical thresholds of various technical parameters, which are summarized in "table of numerical threshold". Purpose of the study in this paper is to verify the practical feasibility of the "table of numerical threshold" in terms of choice of parameters and the definition of numerical boundaries of each parameter. Although all structural types are the subjects of JSCA Code, steel structures are chosen as subjects of this study. First, basic concepts of JSCA Code are summarized followed by introduction of numerical threshold for defining seismic performance grades. Then, the results of dynamic time history response analyses of model buildings of steel structures with and without dampers or seismic isolation systems, which are conducted for the level-2 seismic action in designing high-rise buildings, are shown and efficiency of "table of numerical threshold" is studied in the light of the results. Finally, a proposal of method to classify seismic performance grade with simple indexes based on the numerical threshold of selected parameters is shown.

抄録全体を表示

本論では慣性質量要素を利用した非線形粘性ダンパー(MVDs)を提案している。本研究のねらいは、非線形MVDsが１自由度系の応答に与える影響を調べることである。まず最初に非線形MVDの動的特性について述べているが、そこではダンパーのエネルギー吸収能力を付加減衰定数hsdにより扱い、またダンパーの非線形性についてはパラメーターaにより扱っている。さらに、非線形MVDsを有する構造物の応答特性は、hsd、a、それと付加質量比r(=付加質量／層質量)の３つの無次元パラメーターにより説明できることを示す。そして、付加減衰、ダンパーの非線形性、それに付加質量比の３つのパラメーターが１自由度系の自由振動、定常調和振動、地震応答に与える影響について検討している。最後に、構造物の応答予測法および目標応答変位に対するダンパーの設計法の２つの設計問題について触れている。

抄録全体を表示

Seismic diagnosis has been carried out to improve the seismic safety of residential houses including those of traditional wooden houses by Kyoto municipal government. In this paper, we compiled the seismic evaluation data of 882 traditional wooden houses. Then, we statistically analyzed the structural characteristics indices of houses such as equivalent natural period and equivalent damping coefficient. We also analyzed the seismic performance indices such as the base shear coefficient. Finally, a seismic evaluation method of traditional wooden houses is also analyzed.

抄録全体を表示

Twenty years have passed since response control systems, which reduce structural damages caused by earthquakes or strong winds, were used in actual buildings. JSCA conducted a survey of response controlled buildings on design offices and construction companies, and made a database. Based on the database, first, this paper classified the number of the buildings which use response control systems by construction years, purposes of the buildings and types of device mechanisms. And, this paper analyzed the distribution of the applied damping forces, and their response reduction efficiency. Finally, this paper reports the result of this analysis, and discusses the present situation of response control systems in Japan.

抄録全体を表示

The purpose of this study is to improve the prediction accuracy of the maximum deformation of the wood structure in time-history response analysis. We propose a method to examine a damping mechanism on the basis of energy response. First, in order to approximate damping energy of wood structure, we derive formulas for V_D/V_E =f(h)_W or f(h,μ)_W through the damping factor of wood structure. Equivalent velocity V_E is converted from total input energy and equivalent velocity V_D, from energy attributable to damage. Next, based on the assumption that the damping force is proportional to the relative velocity, we estimate the viscous damping coefficient by the relation between the relative velocity and damping energy calculated by the approximation formulas. Finally, we estimate the damping coefficient of full-scale wood structure frame by proposed method, confirming the validity of proposed method.

抄録全体を表示

Structural design review systems in various regions of the United States were investigated by directly asking questions to 57 experts of structural design including structural engineers, academic researchers and building officials. Answers from 18 of these experts were obtained and based on their responses details of the structural design review systems were studied including design review by building authorities, peer review and their relationships. There are four notable findings: (i) There are significant differences in structural review systems between different states or jurisdictions. (ii) The design review systems answered in the questionnaire can be categorized into four groups represented by West coast, city of Chicago, state of Massachusetts, and New York City. (iii) The peer review system, which is well-known as an effective design review system among building experts and owners, is utilized in most states, although with different styles of application. (iv) Engineers of record always take the ultimate responsibility of the structural design and there is no responsibility on peer reviewers or building authorities.

抄録全体を表示

Responses of a high rise reinforced concrete building with 20 stories were determined subjected to earthquake and impact load due to collision of Cessna airplane. Three collision points were adopted, that is, the higher floor 19, the middle floor 12 and the lower floor 7. The impact load was obtained based on knowledge from the full-scale aircraft impact test and impact velocities for cessna was selected as two levels. Consequently, the deformation and force due to collision of Cessna airplane with impact velocity of 400km/h was 1/10 to 1/30 those subjected to design seismic waves and therefore it was proved that the collapse of the building would not occur.

抄録全体を表示

In 1981, many detached houses collapsed owing to the earthquake which took place at the coast of Miyagi Prefecture in Japan because ferroconcrete was not used as the base of the most of collapsed houses. Therefore, the earthquake-proof design criterion was revised and it obliged newly constructed houses to use ferroconcrete as the base of detached houses since then. However, there are still more than ten million detached houses using aged concrete alone as the base in Japan. In this paper, a reinforcement method for the aged concrete is demonstrated by using the high performance CFRP strips. Three kinds of concrete beams reinforced with the CFRP strips with different vertical insert positions and different numbers of the CFRP strips were tested by a four point bending test method. In order to clarify the effects of CFRP strips, a concrete beam without reinforcement was also tested. The results of the experiment showed that the maximum deflections of the concrete beams reinforced with the CFRP strip were more than one hundred times larger than those of the concrete beams without reinforcement. Although the concrete beam without the CFRP strips collapsed instantly, the concrete beam reinforced with the CFRP strips gradually failed similar to the plastic behavior of metals. This result means that the residents can afford to escape safely from the houses in the event of possible earthquakes. The experimental results were compared with the analytical ones. Both results showed good agreement and the effectiveness of base concrete reinforced with CFRP strips was demonstrated.

抄録全体を表示

The calculation method of response and limit strength has been used to evaluate the seismic performance of traditional wooden houses in Kyoto. In this paper, firstly, we compared the characteristics of the four seismic performance diagnosis methods based on calculation method of response and limit strength. Secondly, we evaluated the seismic performance of one standard traditional wooden house in Kyoto by the four methods. Finally, we analyzed the factors that cause differences in the results, focusing on the skeleton curve, response calculation method, and ground amplification ratio.

抄録全体を表示

本稿は, 建築物の既存鉄筋コンクリート造基礎杭を再利用する上で参考となるように, 過去の事例, 杭の品質調査方法, 再利用時の検討手順等の概要を紹介するものである。

抄録全体を表示

“Vertical slits” are structural slits, which structurally insulate non-load bearing walls from main members, positioned between columns and wing walls. Lateral pressure from concrete acts on vertical slits during deposition of concrete. There is no method other than empirical rules to evaluate rigidity and yield strength of vertical slits against lateral pressure in practice. There are cases when vertical slits fall off because of lateral pressure, forcing repair work to be carried out. We have conducted experiments to obtain the rigidity and yield strength of vertical slits against lateral pressure. Vertical slits were loaded with loads equivalent to lateral pressure from concrete. Concrete was deposited into full-scale RC columns with vertical slits. We report methods to evaluate resistance of structural slits against lateral pressure from concrete based on these experiments in this work.

抄録全体を表示