Study On Seismic Performance Of Linked Column Steel Braced Frame With Lifting Column Base

The linked column steel braced frame is a new type of double lateral force resisting structure,which is formed by independent braced frames connected through links.It has significant yield sequence,of which links first enter elastoplasticity to dissipate energy under the action of earthquake and non-energy dissipation members develop plasticity only when the deformation is too large.The linked column steel braced frame can restore to its original position by its own elastic stiffness through removing the links which developed plasticity after earthquake,which reduces the repair costs greatly.The lifting column base used in linked column steel braced frame can make the vertical deformation of the links increase under the same horizontal load,the energy dissipated by the links increase,energy dissipation will be concentrated to a greater extent.In order to research the seismic behavior of the linked column steel braced frame with lifting column base,finite element analysis software ABAQUS was used to simulate the seismic behavior of the linked column steel braced frame with lifting column base in this paper.The main research works are summarized as follows:(1)A 3×5-span 15-story linked column steel braced frame was designed using SAP2000 according to relevant codes and a 1-span 3-story structure was selected as the BASE specimen for solid finite element analysis.(2)The modeling process of specimen BASE with ABAQUS was introduced in detail,and the reliability of the whole modeling process was verified by the simulation of two experiments.(3)The seismic performance of specimen with lifting column base and the specimen with ordinary rigid column base was compared.The results show that the failure mode of specimen with lifting column base is more ideal,the energy dissipation mechanism is more reasonable,the ductility is better and the energy dissipation capacity is stronger.(4)In order to study the influence of span,story and steel strength grade of the braced frame on the seismic performance of structure,three series of specimens with lifting column base were designed.The results show that the seismic performance of the structure can be the best if the high-span ratio of the structure is in the range of 0.4~0.5.With the advancement of the steel strength of braced frame,the ultimate bearing capacity and the residual stiffness of the specimens are increased,the degree of damage is reduced,which is beneficial to the repair of the structure after earthquake,but the ductility is decreased.(5)The positive skeleton curves of the structure which in different heights,storiesand steel strength of braced frame were simplified to the trilinear model according to the principle of equal energy to determine the replacement range of the link.The results show that for the structure with links using Q235 B and braced frame using Q345 B,the lower limits of the replacement range of the link is 1/550,and the upper limits of the replacement range of the link is 1/130.For the structure with braced frame using Q235B?Q390B?Q420B?Q460C?Q550C respectively,the upper limits of the replacement range of the link decline 31%?improve 4%?19%?32%?42% respectively.