Research On Seismic Pounding Response And Pounding Mitigation Measures Of Adjacent Reinforced Concrete Frame Structures

A large number of earthquakes around the world indicate that seismic pounding between adjacent structures are one of the important factors leading to structural damage.There are a large number of existing structures with insufficient spacing of adjacent buildings,and the hidden dangers of seismic pounding are serious.However,the research on seismic collision mechanism,response law and anti-collision measures is insufficient by using refined finite element analysis.Therefore,this paper takes the adjacent reinforced concrete frame structure with equal total height and unequality in actual engineering as the research object,analyzes the seismic collision response,and studies the influence of collision force on the response of adjacent structures through deterministic and probabilistic methods.Regularity,and based on this,put forward effective and practical measures to reduce pounding.The main research contents and conclusions of this paper are as follows:(1)A three-dimensional refined finite element model modeling method based on ABAQUS for seismic pounding of adjacent reinforced concrete frame structures is proposed,including implicit solution algorithm,equivalent seismic force input excitation,and beam-column plate combination to simulate the cast-in-place of concrete.The function,the reinforcement of the steel frame embedded in the concrete,the creation of contact pairs,the definition of the master-slave contact simulation pounding,the contact algorithm using the penalty function method,etc.,the finite element simulation of the pounding response of two adjacent reinforced concrete frame structures,the analysis results and The results of the shaking table test are in good agreement,and the feasibility of the proposed modeling method is verified.(2)Based on the proposed finite element modeling method,the influence of seismic pounding on the structural dynamic response of two adjacent reinforced concrete frame structures with equal total height is analyzed.The results show that the adjacent contour structures produce large pounding forces under strong earthquakes,resulting in an increase in acceleration,displacement,pounding stress and concrete damage.(3)Based on the proposed finite element modeling method,the influence law of the six-story and four-story adjacent reinforced concrete frame structures with unequal heights on the dynamic response of the structure due to seismic poundings under three seismic waves is analyzed,and the influence parameter analysis is carried out.Including seismic wave loading direction,structure spacing,peak acceleration,period ratio and other parameters.The results show that the seismic wave is loaded in the forward or reverse direction along the pounding direction of the structure.Due to the change of relative displacement time history,the pounding response of adjacent structures is significantly different.As the structure spacing increases,the pounding force and the number of poundings decrease.Trend;as the peak acceleration of the seismic wave increases,the structural response caused by the pounding increases gradually;the six and three-story,six and four-story,six and five-story adjacent structures gradually approach each other,and the structure responds first.After increasing and decreasing,the adjacent structures of the six and four story have the largest response.(4)Using the dynamic incremental analysis method,the maximum interlayer displacement angle of the structure and the maximum interlayer displacement angle of the floor are taken as the damage state damage indicators respectively.The Open Sees model of the six-story and four-story adjacent reinforced concrete frame structures considering the impact force is carried out.Seismic vulnerability analysis analyzes and analyzes the effect of structural spacing on vulnerability.The results show that the seismic pounding increases the failure probability of the story above the pounding story(the 4th floor)of the six-story structure,reduces the failure probability of the pounding story and the following stories,and increases the failure probability of the pounding story of the four-story structure.The increase of the spacing of adjacent structures will aggravate the failure probability of the pounding story and the lower story of the six-story structure,and reduce the failure probability of the story above the pounding story.The failure probability of each story of the four-story structure will gradually decrease due to the increase of the spacing.(5)The rubber filled between adjacent structures is used as the anti-pounding measure.The finite element modeling method is used to analyze the anti-pounding effect of the six-story and four-story adjacent reinforced concrete frame structures under the action of El Centro wave.Its influence on structural seismic vulnerability.The results show that: rubber as a vibration-absorbing material has good impact-reducing effect;increasing rubber thickness can reduce pounding force,acceleration,displacement,interlayer displacement angle,tensile and compression damage,but increase the number of poundings;increase rubber hardness will cause structural pounding force And the acceleration response is increased;the structural stiffness is reduced due to the reduction of the pounding stiffness caused by the filling rubber.