Seismic Performance Of PPEFF-BRB Structural System

Prefabricated concrete structure has the characteristics of fast construction speed,low pollution,high quality assurance rate and good durability,received extensive research and attention at home and abroad,and be vigorously promoted and used in construction projects.Compared with traditional cast-in-place structure,the seismic performance of prefabricated reinforced concrete frame structure is insufficient,using energy dissipation and shock absorption technology can effectively improve the overall performance of the assembled structure.This paper systematically performs refined finite element modeling on the shock-absorbing system and the toughness system of the new prefabricated frame structure with ordinary anti-buckling restraint support and self-reset anti-buckling restraint support respectively,the dynamic elastoplastic analysis is carried out by ABAQUS to study the dynamic characteristics of PPEFF structure under different types of ground motions,the results show that the self-reset anti-buckling constrained support in the ductile system not only has good anti-buckling constrained support with good shock absorption performance,And it can reflect the self-reset characteristic by reducing the residual deformation,The main research contents and results of this article are as follows:(1)The destructive static loading test of the BRB is carried out to study its ultimate failure performance.The results show that the experimental results of the BRB test member meet the design requirements,the ultimate performance exceeds the expected target,and its cumulative plastic deformation reaches 425 times the yield displacement,and the cumulative plastic loss Can be 2534.12 k N·m.(2)Aiming at the shortcomings of insufficient overall performance of the PPEFF system,It proposes a shock-absorbing design method based on performance design in accordance with the goal of improving half-degree shock-absorbing design,and according to the Ra-Rd shock absorption performance curve for shock absorption design and analysis.The results show that Under the action of frequent ground motions,fortification ground motions and rarely ground motions,the new fabricated frame structure and the shock-absorbing structure are in an safe state,and the displacement angle between the layers of the shock-absorbing structure is reduced by 23.11%,18.68% and 32.22%,achieving the performance design goal of improving the half degree.(3)The PPEFF-earthquake-resistant system and PPEFF-shock-absorbing system were numerically analyzed under four different types of ground motions,the results show that under different types of ground motions,neither the anti-seismic system nor the shock-absorbing system collapsed,and the anti-seismic system can maintain the interlayer displacement angle within the limit value of the interlayer displacement angle [1/50] specified in the "Seismic code",the shock absorption system can achieve the performance design goal of improving the half degree [1/80].The floor acceleration,base shear force and foundation incoming energy of the shock-absorbing structure are increased,but ordinary BRB can consume more than 20% of the energy of the shock absorption system,reduce the energy of the main structure to bear more than 24.26%,under the effect of near-field pulseless ground motion,able to bear 47.08% of the main structure energy,fully protect the safety of the main structure of the new assembly frame.(4)Design the self-reset BRB self-reset system using the same core specifications,calculate the restoring force model of the self-reset BRB from the design results,and establish a new fabricated frame structure-toughness system.Assuming that the residual deformation of the structure exceeds 0.5%,the normal function of the structure is destroyed,at this time,it needs to be fully repaired or even pushed to reconstruction to continue to be put into use,under the rare and rare strength of the damping system and the toughness system,four different types of ground motion analysis found: the selfreset BRB itself has a large stiffness that can constrain the displacement angle between layers,at the same time will increase the peak floor acceleration and base shear.Selfresetting BRB has weaker overall energy than ordinary BRB dissipation structure,but self-resetting BRB can dissipate more energy in near-field pulseless ground motion and far-field long-period ground motion.(5)Under the action of rare ground motions,the shock absorption system can maintain normal function under four different ground motions.Under extremely rare ground motion,ordinary ground motion will cause the lateral residual deformation of the shock-absorbing system to exceed the assumed residual deformation limit of 0.5%.The rest of the ground motions are close to this limit,and the shock absorption system is facing the risk of damage.The ductile system can maintain the new fabricated frame structure-the residual deformation of the ductile system is below 0.1% under the action of rare and extremely rare ground motions,and realizes self-reset characteristics to reduce structural damage.(6)Taking the maximum displacement angle of the structural member column as the damage judgment parameter,the damage analysis of the vertical load-bearing components in the shock absorption system and the toughness system.Comparison of the damage severity of the two systems: Long-period ground motion> near-field no-pulse motion> near-field pulse motion>ordinary ground motion.At the same time,a maximum of 68 structural columns with severe damage appear in the shock-absorbing system,requiring overhaul work,however,the above-mentioned damage state is not severely damaged in the tough system,and the structure can work normally.The toughness system can achieve the design goal of "repairable by large earthquakes and not collapsed by extreme earthquakes" make PPEFF structure more safe and reliable.