| Reinforced concrete structural wall systems with high carrying capacity and lateral stiffness are widely used in high-rise buildings,and the coupled wall structure is an important branch of the systems.Coupled wall structures with reasonable design not only satisfie the demands of the architectural function,but also can effectively generate the dual mechanism of seismic precautionary.However,the optimized analysis of geometry dimensions of reinforced concrete coupled wall structures is usually in elastic for single response.In order to optimize the geometric design of the structures,it is indispensible to investigate the influence on seismic behaviors of reinforced concrete coupled wall structures in elastic-plastic stage due to geometric parameters.Following Chinese design codes and CCF criteria of central composite design,structural models were established on the basis of taking reinforced concrete coupled walls as the research objects,and taking aspect ratio of walls and span-depth ratio of coupling beams as key parameters.The top drift ratio and destructive story drift ratio were adopted as deformation indicators,and static push analysis,dynamic time history analysis,and seismic fragility analysis based on IDA were adopted to investigate carrying capacity,deformation capacity,stiffness degradation,damage mode,failure probability at various performance levels and corresponding margin capacity.Furthermore,founded on the nonlinear analytical results,the double-factorial quadratic response surface analysis was used to investigate the influence on structural properties due to two geometric parameters.In addtion,the factors of significance were revealed through F test,and the optimal value of factors was obtained based on the comprehensive optimization analysis,thus the design plan of reinforced concrete coupled walls was optimized.Based on research work of this paper,the main conclusions were as follows.(1)The peak load carrying capacity and initial stiffness of structures increased with the decrease of span-depth ratio of coupling beams and reduced with the augment of aspect ratio of walls.The structures with the elastic coupling ratio between 0.348 and 0.584 had higher ductility.(2)In terms of top drift ratio,nominal story drift ratio and destructive story drift ratio,aspect ratio of walls under the condition of small,small span-depth ratio of coupling beams reached minimum response.However,aspect ratio of walls under the condition of medium or large,the responses had a minimum value at span-depth ratio of coupling beams in medium level.(3)Once span-depth ratio of coupling beams dropped to low level,structural story shear increased significantly with the augment of aspect ratio of walls.Bending moment at ends of coupling beams increased with the decrease of span-depth ratio of coupling beams or the augment of aspect ratio of walls,and the height ratio of maximum bending moment of coupling beams reduced.With the increase of aspect ratio of walls,bending moment at the bottom of each wall increased significantly.Moreover,structures with elastic coupling ratio between 0.487 and 0.642 brought about lower damage.(4)With enlarged deformation,structures subjected to seismic intensity increased linearly,and the increasing gradient of seismic intensity raised with the decrease of spandepth ratio of coupling beams or aspect ratio of walls.In addition,logarithmic standard deviations of ?top under the condition of Sa(T1,5%)were small and tended to be stable when structural basic natural vibration periods were greater than 1s.(5)In performance level of normal service,functional disruption or collapse prevention,the median values of structural seismic fragility increased and the structural failure probability under same spectral acceleration reduced because of the decrease of span-depth ratio of coupling beams or aspect ratio of walls.Moreover,reinforced concrete coupled walls designed according to current code met the requirements of three seismic design levels and the structures with elastic coupling ratio between 0.487 and 0.642 had better collapse-resistant capacity.(6)From the perspective of structural margin ratio at each performance level,the structural EMR raised with the decrease of span-depth ratio of coupling beams or aspect ratio of walls.The structural PMR reached maximum when span-depth ratio of coupling beams were in the middle level,and the structural PMR raised with the decrease of aspect ratio of walls.The aspect ratio of walls under the condition of small or medium,the structural CMR raised with the decrease of span-depth ratio of coupling beams.But aspect ratio of walls under the condition of large,the structural CMR reached maximum when span-depth ratio of coupling beams were in the middle level.In addition,with increase of performance level,span-depth ratio of coupling beams and aspect ratio of walls had less influence on structural margin ratio.(7)The factorial significant analysis shows that span-depth ratio of coupling beams had significant influence on peak load carrying capacity,maximum destructive story drift ratio and base shear,maximum bending moment of coupling beam and structural CMR.And aspect ratio of walls had significant influence on initial stiffness,top drift ratio and maximum nominal story drift ratio and the median value of seismic fragility.Moreover,span-depth ratio of coupling beams and aspect ratio of walls had same influence on ultimate drift ratio,maximum bending moment of wall,structural EMR and PMR.(8)Comprehensive optimization of geometric parameters had shown that structural responses with minimum aspect ratio of walls always achieved optimal value,and optimal value of span-depth ratio of coupling beams increased exponentially with the augment of aspect ratio of walls.Furthermore,when the aspect ratio of walls was between 3 and 6.6,optimal value of span-depth ratio of coupling beams was between 3.49 and 4.10,meaning that for reinforced concrete coupled wall with flexural deformation,the span-depth ratio of coupling beams should be in small or middle level. |
PDF Full Text Request