| The use of recycled coarse aggregates to partially replace natural aggregates,and industrial waste lithium slag to partially replace cement for concrete preparation,which is helpful for the protection of natural stone and other resources and the recycling of resources,and can reduce the amount of lithium slag stocked,which is important Environmental benefits,economic benefits and social benefits.my country is a country prone to earthquakes.To make lithium slag recycled concrete widely used in engineering,it is necessary to understand its seismic performance.The beam-column joints play a very important role in the working performance of the frame structure.Therefore,it is necessary to improve the lithium slag recycled concrete Test research on seismic performance is carried out.This paper takes the beam-column node of the frame structure as the research object,conducts pseudo-static tests on the 6-thickness lithium slag recycled concrete beamcolumn node,and studies the test pieces of each node under different lithium slag content,core area hoop ratio,and beam-column section height In terms of differences in seismic performance indicators such as hysteresis curve,skeleton curve,ductility coefficient and bearing capacity degradation,analyze the influence of lithium slag content,core zone hoop ratio,beam-to-column section height ratio on seismic performance and shear capacity.Combining the experimental data and based on the shear mechanism of ordinary concrete,a formula for calculating the shear bearing capacity of the beamcolumn joints of recycled concrete with lithium slag is proposed.The main conclusions are as follows:(1)The peak load of ZJ2 is 5.6% higher than that of ZJ4.The cumulative energy consumption per turn under peak load and failure load is 1.03 times and 1.17 times that of ZJ4,respectively,and the ductility coefficient is increased by about 12%,indicating that the appropriate amount of lithium is added In the case of slag,the peak load,energy consumption performance and ductility of the specimen can be improved.The ductility coefficient of ZJ3 is about 5% higher than that of ZJ2,and the ductility coefficient of ZJ6 is about 10% higher than that of ZJ5.The cumulative energy consumption per turn of ZJ3 and ZJ2 in the ultimate deformation state is 2.59 times and 2.76 times that of ZJ1,respectively.The accumulative energy consumption per lap is 1.09 times that of ZJ5,which shows that with the increase of core hooping ratio,the ductility and energy consumption capacity of the test piece gradually increase.The ductility coefficient of ZJ5 is about 70% higher than that of ZJ1,and the ductility coefficient of ZJ6 is about 20%higher than that of ZJ2.It shows that increasing the beam-to-column section height ratio within a certain range can increase the ductility of the specimen,but the appropriate stirrups can be weakened.The effect of beam-to-column section height ratio on the ductility of specimens.(2)When the beam-to-column section height ratio is 1.0,the crack resistance and shear resistance of the specimens increase with the increase of the core zone hooping ratio.The crack resistance of ZJ2 is 17.8% higher than that of ZJ1.The bearing capacity has increased by 35%.When the hoop ratio in the core area is 0,the shear capacity of ZJ5 is about 1 times higher than that of ZJ1.When the hoop ratio in the core area is 0.218%,the shear capacity of the two is basically the same,indicating that it is within a certain range.Increasing the ratio of beam-to-column section height can increase the shear capacity of the specimen,but arranging an appropriate amount of stirrups in the node area can weaken its influence on the shear capacity.Compared with ZJ4,the shear bearing capacity of ZJ2 is increased by 16.1%,and the crack resistance capacity is increased by 5.6%,indicating that the appropriate amount of lithium slag can improve the shear capacity of the specimen.(3)Combining the calculation methods of the crack resistance and shear resistance of the ordinary concrete beam-column joints,and considering the weakening of the interface caused by the new and old mortar in the lithium slag recycled concrete and the restraint of the orthogonal beams perpendicular to the core area,Supplemented the relevant influence coefficient and revised the calculation formula of ordinary concrete.The corresponding theoretical values of crack resistance and shear resistance are calculated by using the modified formula,and compared with the experimental values obtained from the formula obtained by bringing the test data into the force analysis of the middle node.It is found that the values of the two are close to each other,and the dispersion coefficient and the coefficient of dispersion are compared.The standard deviation is also relatively small,and the experimental value has a certain safety reserve relative to the theoretical value,indicating that the correction formula proposed in this article can be used as a reference for engineering practice. |
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