In many cases, seismic appraisal of existing structures is carried out by the two step method and seismic strengthening of R.C. frame structures is solved just based on rough calculation or experience of designers, wh...In many cases, seismic appraisal of existing structures is carried out by the two step method and seismic strengthening of R.C. frame structures is solved just based on rough calculation or experience of designers, which may lead to either lack of safety or too conservative in design. According to some related criteria and experts experience, a computer program is developed specially for seismic appraisal and seismic strengthening of R.C. frames (not more than 10 storeys) in this paper. Because the progra...展开更多
Reinforced concrete （r.c.） framed buildings designed in compliance with inadequate seismic classifi- cations and code provisions present in many cases a high vulnerability and need to be retrofitted. To this end, th...Reinforced concrete （r.c.） framed buildings designed in compliance with inadequate seismic classifi- cations and code provisions present in many cases a high vulnerability and need to be retrofitted. To this end, the insertion of a base isolation system allows a considerable reduction of the seismic loads transmitted to the super- structure. However, strong near-fault ground motions, which are characterised by long-duration horizontal pulses, may amplify the inelastic response of the superstructure and induce a failure of the isolation system. The above considerations point out the importance of checking the effectiveness of different isolation systems for retrofitting a r.c. framed structure. For this purpose, a numerical inves- tigation is carried out with reference to a six-storey r.c. framed building, which, primarily designed （as to be a fixed-base one） in compliance with the previous Italian code （DM96） for a medium-risk seismic zone, has to be retrofitted by insertion of an isolation system at the base for attaining performance levels imposed by the current Italian code （NTC08） in a high-risk seismic zone. Besides the （fixed-base） original structure, three cases of base isolation are studied： elastomeric bearings acting alone （e.g. HDLRBs）; in-parallel combination of elastomeric and friction bearings （e.g. high-damping-laminated-rubber beatings, HDLRBs and steel-PTFE sliding bearings, SBs）; friction bearings acting alone （e.g. friction pendulum bearings, FPBs）. The nonlinear analysis of the fixed-base and base-isolated structures subjected to horizontal com- ponents of near-fault ground motions is performed for checking plastic conditions at the potential critical （end） sections of the girders and columns as well as critical conditions of the isolation systems. Unexpected high val- ues of ductility demand are highlighted at the lower floors of all base-isolated structures, while re-centring problems of the base isolation systems under near-fault earthquakes are expected in case of friction beatings acting alone （i.e. FPBs） or that in combination （i.e. SBs） with HDLRBs.展开更多
In order to study the dynamic behaviour of construction,specifically seismic response of structures,as many researchers did,we have resorted to modelling methods,based on the scaled internal forces.Therefore,this rese...In order to study the dynamic behaviour of construction,specifically seismic response of structures,as many researchers did,we have resorted to modelling methods,based on the scaled internal forces.Therefore,this research includes results of an experimental investigation aimed to establish the possibility of realistic simulations of the cyclic response of small-scale models of one bay,one-storey reinforced concrete frames with masonry infills as a preliminary step for simulating the dynamic response of such structural.So,the specimens constructed were 1:9 scale R/C frames.These 1:9 scale infill frames were constructed with prototype materials and were tested in an extensive experimental sequence representing specimens of a scale near the prototype(1:3).The tested laboratory models include 1:3 scale infilled R/C frames that were built from original material such as steel,concrete and masonry infills(hollow masonry units and mortar).With the same scale,geometry and construction materials used for the construction of a 1:3 scale 5-story three dimensional building.This program consisted of 16 models,5 bare and 11 masonry infilled.all models refer to single-storey one-bay 1:9 scale as for the original structure and a one third of the scale(1:3)as for the prototype(1:3).The reinforced concrete specimens were designed in such a way as to prevent shear failure of the columns.Finally,the present paper was carried out in the Laboratory of Strength of Materials and Structures in the Department of Civil Engineering at Aristotle University of Thessaloniki.展开更多
October 19,2007 Vice Premier Wu Yi,PRC On behalf of Chinese government,I would like to congratulate the 20th Foundation of World Federation of Acupuncture-Moxibustion Societies(WFAS)and International Acupuncture Congr...October 19,2007 Vice Premier Wu Yi,PRC On behalf of Chinese government,I would like to congratulate the 20th Foundation of World Federation of Acupuncture-Moxibustion Societies(WFAS)and International Acupuncture Congress which is to be held in Beijing,China.And also I give my warm welcome and regards to TCM/Acupuncture colleagues all over the world.展开更多
Foreword Since the foundation of P.R.C.,the China's power grid develops with a high rate.By now,grids in all provinces except Xinjiang,Tibet,Hainan and Taiwan are AC/DC interconnected together,forming the structur...Foreword Since the foundation of P.R.C.,the China's power grid develops with a high rate.By now,grids in all provinces except Xinjiang,Tibet,Hainan and Taiwan are AC/DC interconnected together,forming the structure of power grid interconnection in the whole country.展开更多
JIANG Zemin, President of the People’s Republic of China, once said: "Respecting women and protecting women is an important sign of social progress. It should become a civilized society’s legal provision and mo...JIANG Zemin, President of the People’s Republic of China, once said: "Respecting women and protecting women is an important sign of social progress. It should become a civilized society’s legal provision and moral concept." On October 1, 1992 the Law of the P.R.C. on the Protection of Rights and Interests of Women was put into effect, which was considered a major accomplishment for China and Chinese women. More than two years have passed since the implementation of the law. How well has the law展开更多
文摘In many cases, seismic appraisal of existing structures is carried out by the two step method and seismic strengthening of R.C. frame structures is solved just based on rough calculation or experience of designers, which may lead to either lack of safety or too conservative in design. According to some related criteria and experts experience, a computer program is developed specially for seismic appraisal and seismic strengthening of R.C. frames (not more than 10 storeys) in this paper. Because the progra...
基金financed by Re.L.U.I.S.(Italian network of university laboratories of earthquake engineering),under the project "Convenzione D.P.C.-Re.L.U.I.S. 2014-2016,WPI,Isolation and Dissipation"
文摘Reinforced concrete （r.c.） framed buildings designed in compliance with inadequate seismic classifi- cations and code provisions present in many cases a high vulnerability and need to be retrofitted. To this end, the insertion of a base isolation system allows a considerable reduction of the seismic loads transmitted to the super- structure. However, strong near-fault ground motions, which are characterised by long-duration horizontal pulses, may amplify the inelastic response of the superstructure and induce a failure of the isolation system. The above considerations point out the importance of checking the effectiveness of different isolation systems for retrofitting a r.c. framed structure. For this purpose, a numerical inves- tigation is carried out with reference to a six-storey r.c. framed building, which, primarily designed （as to be a fixed-base one） in compliance with the previous Italian code （DM96） for a medium-risk seismic zone, has to be retrofitted by insertion of an isolation system at the base for attaining performance levels imposed by the current Italian code （NTC08） in a high-risk seismic zone. Besides the （fixed-base） original structure, three cases of base isolation are studied： elastomeric bearings acting alone （e.g. HDLRBs）; in-parallel combination of elastomeric and friction bearings （e.g. high-damping-laminated-rubber beatings, HDLRBs and steel-PTFE sliding bearings, SBs）; friction bearings acting alone （e.g. friction pendulum bearings, FPBs）. The nonlinear analysis of the fixed-base and base-isolated structures subjected to horizontal com- ponents of near-fault ground motions is performed for checking plastic conditions at the potential critical （end） sections of the girders and columns as well as critical conditions of the isolation systems. Unexpected high val- ues of ductility demand are highlighted at the lower floors of all base-isolated structures, while re-centring problems of the base isolation systems under near-fault earthquakes are expected in case of friction beatings acting alone （i.e. FPBs） or that in combination （i.e. SBs） with HDLRBs.
文摘In order to study the dynamic behaviour of construction,specifically seismic response of structures,as many researchers did,we have resorted to modelling methods,based on the scaled internal forces.Therefore,this research includes results of an experimental investigation aimed to establish the possibility of realistic simulations of the cyclic response of small-scale models of one bay,one-storey reinforced concrete frames with masonry infills as a preliminary step for simulating the dynamic response of such structural.So,the specimens constructed were 1:9 scale R/C frames.These 1:9 scale infill frames were constructed with prototype materials and were tested in an extensive experimental sequence representing specimens of a scale near the prototype(1:3).The tested laboratory models include 1:3 scale infilled R/C frames that were built from original material such as steel,concrete and masonry infills(hollow masonry units and mortar).With the same scale,geometry and construction materials used for the construction of a 1:3 scale 5-story three dimensional building.This program consisted of 16 models,5 bare and 11 masonry infilled.all models refer to single-storey one-bay 1:9 scale as for the original structure and a one third of the scale(1:3)as for the prototype(1:3).The reinforced concrete specimens were designed in such a way as to prevent shear failure of the columns.Finally,the present paper was carried out in the Laboratory of Strength of Materials and Structures in the Department of Civil Engineering at Aristotle University of Thessaloniki.
文摘October 19,2007 Vice Premier Wu Yi,PRC On behalf of Chinese government,I would like to congratulate the 20th Foundation of World Federation of Acupuncture-Moxibustion Societies(WFAS)and International Acupuncture Congress which is to be held in Beijing,China.And also I give my warm welcome and regards to TCM/Acupuncture colleagues all over the world.
文摘Foreword Since the foundation of P.R.C.,the China's power grid develops with a high rate.By now,grids in all provinces except Xinjiang,Tibet,Hainan and Taiwan are AC/DC interconnected together,forming the structure of power grid interconnection in the whole country.
文摘JIANG Zemin, President of the People’s Republic of China, once said: "Respecting women and protecting women is an important sign of social progress. It should become a civilized society’s legal provision and moral concept." On October 1, 1992 the Law of the P.R.C. on the Protection of Rights and Interests of Women was put into effect, which was considered a major accomplishment for China and Chinese women. More than two years have passed since the implementation of the law. How well has the law
