| With the continuous development of economy and society,the construction technology of assembled bridge piers has become one of the main development directions of bridge construction technology in China with its characteristics such as short construction period,high engineering quality and green environmental protection.In China,the research topic of confined concrete column filled with steel tube has been more mature,which has the advantages of high bearing capacity,good plasticity and toughness,good seismic performance,good economy and so on.Therefore,this article puts forward the constraint of prefabricated concrete filled square steel tubes structure piers,expect it can combine the characteristics of steel tube confined concrete column,has the construction of good quality,high efficiency,high bearing capacity,good seismic performance,simplify the construction process and good economic benefit,is expected to be an ideal type of piers for high pier Bridges(such as laba Jin Bridge).Therefore,this paper takes the prefabricated concrete piers constrained by square steel tubes as the research object,conducts hysteretic performance tests and finite element extended parameter analysis,and puts forward the restorative force model of the prefabricated concrete piers which is suitable for the restriction of square steel tubes.(1)We carry out 4 constraints of prefabricated concrete filled square steel tubes and piers,1root square steel tube constraints,the overall cast-in-place concrete pier,1 overall cast-in-place concrete pier,prefabricated concrete piers of a traditional grouting sleeve connection pseudo-static experiment research,test parameters for different forms of constraint and the connection between prefabricated pier and the pile caps is structure,analysis of the specimen hysteresis curves,skeleton curves,ductility,energy dissipation mechanism,the strength and stiffness degradation,the displacement of the residual deformation and seismic performance indicators,this paper discusses the failure modes of the specimens.The test results show that,compared with the traditional prefabricated concrete piers and integral cast-in-place concrete piers,the prefabricated concrete piers with grouting tubes connected by square steel tubes have higher horizontal bearing capacity,similar ductility,and good seismic performance.Relative to other connections of square steel tube constraints of prefabricated concrete pier,nested steel pipe with the traditional grouting sleeve connection of square steel tube constraints of prefabricated concrete pier more full hysteretic curve,knead shrink less,energy dissipation ability is stronger,has better seismic performance,recommend to the actual engineering application form of bridge structure.(2)Based on the ABAQUS general finite element platform,an analysis model of prefabricated concrete bridge piers constrained by square steel tubes was established and verified with the experimental results.The influences of axial compression ratio,slender-to-slender-toslender-to-slender-to-slender-to-slender-to-slender-to-slender-to-slender-to-slender-to-slender-toslender-to-slender-to-slender-to-slender-to-steel tubes on the seismic performance of prefabricated concrete bridge piers constrained by square steel tubes were extended and analyzed.The results show that the constraint coefficient,the ratio of the embedded depth of steel tubes to the side length of the pier,the ratio of the diameter of the nested steel tubes to the side length of the pier,and the ratio of the side length of the pier to the thickness of the square steel tubes are the key parameters of the prefabricated concrete piers constrained by the square steel tubes.In a certain range,the increase of axial compression ratio N can properly increase the horizontal peak load of prefabricated concrete piers constrained by square steel tubes,and the displacement ductility coefficient decreases slightly.With the increase of slenderness ratio,the level of the constraint of prefabricated concrete filled square steel tubes and piers peak load,displacement ductility coefficient of appropriate increase.The strength of concrete and the yield strength of square steel tubes have little influence on the seismic performance of prefabricated concrete piers constrained by opposite steel tubes.(3)Parameters based on the finite element analysis results,reference constraint of reinforced concrete filled steel tube column skeleton curve computing framework of unified algorithm,according to the introduction of related parameters influence degree correction coefficient,fitting for constraint of prefabricated concrete filled square steel tubes pier skeleton curve of the characteristic value(elastic stiffness,horizontal displacement of peak load,peak load and decline period of stiffness)and the calculation formula of restoring force model,and is verified by an engineering example.Finally,a reasonable and practical calculation method for restoring force model of prefabricated concrete piers constrained by square steel tubes is given,which provides a theoretical basis for engineering application of prefabricated concrete piers constrained by square steel tubes. |
