This paper presents a review of how the ductile diaphragm concept was formulated,evaluated,improved,and implemented over time to achieve seismically resilient bridges.A particular emphasis is placed on the most recent...This paper presents a review of how the ductile diaphragm concept was formulated,evaluated,improved,and implemented over time to achieve seismically resilient bridges.A particular emphasis is placed on the most recent work that has provided a more fully,and more widely applicable,version of the concept.The paper also addresses how to design buckling restrained braces used as energy dissipating elements in the longitudinal di-rection of multi-span bridges(simple spans or continuous bridges)as part of the ductile diaphragm concept.In all cases,the objective of the ductile diaphragm concept is to concentrate ductility demands in steel energy dissi-pating elements located at the ends of the superstructure spans to protect the substructure(and rest of the su-perstructure)from damage,to ensure that the bridge can remain open to full traffic immediately following an earthquake.展开更多
This study proposes a new post-tensioned precast bridge column(PT-PBC)with a socket connection.Compared to conventional PBCs connected by PT tendons,the combination of the PT tendons with the socket connection can avo...This study proposes a new post-tensioned precast bridge column(PT-PBC)with a socket connection.Compared to conventional PBCs connected by PT tendons,the combination of the PT tendons with the socket connection can avoid tensioning the PT tendons on site,which further accelerates construction speed while improving construction quality and safety.In addition,compared to conventional PBCs with a socket connection,a rocking interface can avoid the formation of a plastic hinge in a column,which greatly alleviates seismic damage to that area.One specimen for quasi-static testing is used to validate the feasibility of this connection type.Subsequently,finite element models(FEM)are established to systematically predict the responses of the proposed columns under lateral cyclic loading.The accuracy of the FEM is verified through quasistatic testing.Next,the influences of the key design parameters of the PT-PBC,including the area ratio and prestress level of the PT tendons,the area ratio of energy dissipation(ED)steel rebars,and the total axial compression ratio on the seismic performances of PT-PBC are systematically investigated.The use of shape memory alloy(SMA)rods as energy dissipation devices and their performances also are investigated.The results show that increasing the area ratio and prestress level of PT tendons has an overall positive impact on the self-centering capacity of the column.The prestress level of PT tendons should be kept between 35%and 55%,depending on different conditions.The total compression axial ratio of the columns should be maintained between 0.3 and 0.4.Both ED steel rebars and SMA rods can boost the column’s energy dissipation capacity,while SMA rods can reduce residual deformation due to their inherent mechanical properties.展开更多
文摘This paper presents a review of how the ductile diaphragm concept was formulated,evaluated,improved,and implemented over time to achieve seismically resilient bridges.A particular emphasis is placed on the most recent work that has provided a more fully,and more widely applicable,version of the concept.The paper also addresses how to design buckling restrained braces used as energy dissipating elements in the longitudinal di-rection of multi-span bridges(simple spans or continuous bridges)as part of the ductile diaphragm concept.In all cases,the objective of the ductile diaphragm concept is to concentrate ductility demands in steel energy dissi-pating elements located at the ends of the superstructure spans to protect the substructure(and rest of the su-perstructure)from damage,to ensure that the bridge can remain open to full traffic immediately following an earthquake.
基金Natural Science Foundation of China under Grant No.52178449,the Beijing Natural Science Foundation under Grant No.8234060the Innovation Center of Beijing Association for Science and Technology。
文摘This study proposes a new post-tensioned precast bridge column(PT-PBC)with a socket connection.Compared to conventional PBCs connected by PT tendons,the combination of the PT tendons with the socket connection can avoid tensioning the PT tendons on site,which further accelerates construction speed while improving construction quality and safety.In addition,compared to conventional PBCs with a socket connection,a rocking interface can avoid the formation of a plastic hinge in a column,which greatly alleviates seismic damage to that area.One specimen for quasi-static testing is used to validate the feasibility of this connection type.Subsequently,finite element models(FEM)are established to systematically predict the responses of the proposed columns under lateral cyclic loading.The accuracy of the FEM is verified through quasistatic testing.Next,the influences of the key design parameters of the PT-PBC,including the area ratio and prestress level of the PT tendons,the area ratio of energy dissipation(ED)steel rebars,and the total axial compression ratio on the seismic performances of PT-PBC are systematically investigated.The use of shape memory alloy(SMA)rods as energy dissipation devices and their performances also are investigated.The results show that increasing the area ratio and prestress level of PT tendons has an overall positive impact on the self-centering capacity of the column.The prestress level of PT tendons should be kept between 35%and 55%,depending on different conditions.The total compression axial ratio of the columns should be maintained between 0.3 and 0.4.Both ED steel rebars and SMA rods can boost the column’s energy dissipation capacity,while SMA rods can reduce residual deformation due to their inherent mechanical properties.
