Segmentally assembled bridges are increasinglyfinding engineering applications in recent years due to their unique advantages,especially as urban viaducts.Vehicle loads are one of the most important variable loads acti...Segmentally assembled bridges are increasinglyfinding engineering applications in recent years due to their unique advantages,especially as urban viaducts.Vehicle loads are one of the most important variable loads acting on bridge structures.Accordingly,the influence of overloaded vehicles on existing assembled bridge structures is an urgent concern at present.This paper establishes thefinite element model of the segmentally assembled bridge based on ABAQUS software and analyzes the influence of vehicle overload on an assembled girder bridge struc-ture.First,afinite element model corresponding to the target bridge is established based on ABAQUS software,and the load is controlled to simulate vehicle movement in each area of the traveling zone at different times.Sec-ond,the key cross-sections of segmental girder bridges are monitored in real time based on the force character-istics of continuous girder bridges,and they are compared with the simulation results.Finally,a material damage ontology model is introduced,and the structural damage caused by different overloading rates is compared and analyzed.Results show that thefinite element modeling method is accurate by comparing with on-site measured data,and it is suitable for the numerical simulation of segmental girder bridges;Dynamic sensors installed at 1/4L,1/2L,and 3/4L of the segmental girder main beams could be used to identify the dynamic response of segmental girder bridges;The bottom plate of the segmental girder bridge is mostly damaged at the position where the length of the precast beam section changes and the midspan position.With the increase in load,damage in the direction of the bridge develops faster than that in the direction of the transverse bridge.Thefindings of this study can guide maintenance departments in the management and maintenance of bridges and vehicles.展开更多
Automatic segment assembly,which increases boring efficiency and construction safety,is a trend in tunnel boring.However,the current situation still relies on manual operation and experience.Electro-hydraulic rotation...Automatic segment assembly,which increases boring efficiency and construction safety,is a trend in tunnel boring.However,the current situation still relies on manual operation and experience.Electro-hydraulic rotation systems are crucial in segment grasping,transporting,and assembly.This article presents the automation of rotation systems in segment assembly to improve motion smoothness and accuracy.As a result of strong nonlinearity and system complexity,parameter estimation is performed by using a noise reduction method based on multialgorithm fusion and the stochastic gradient deviation correction recursive least squares identification algorithm.Active disturbance rejection control(ADRC)is introduced into sliding mode control(SMC)to compensate for model uncertainty and disturbance.An improved cuckoo algorithm is used to optimize influential parameters in ADRC.Moreover,full-scale bench tests are conducted to verify the proposed system automation.Results indicate that the proposed method has a better displacement tracking performance and lower tracking error than the ADRC,SMC,and proportional-integral-derivative methods.Furthermore,such a procedure facilitates the success rate of complete segment assembly.展开更多
基金supported in part by the Key Research Projects of Higher Education Institutions in Henan Province(Grant No.24A560021)in part by the Henan Postdoctoral Foundation(Grant No.202102015).
文摘Segmentally assembled bridges are increasinglyfinding engineering applications in recent years due to their unique advantages,especially as urban viaducts.Vehicle loads are one of the most important variable loads acting on bridge structures.Accordingly,the influence of overloaded vehicles on existing assembled bridge structures is an urgent concern at present.This paper establishes thefinite element model of the segmentally assembled bridge based on ABAQUS software and analyzes the influence of vehicle overload on an assembled girder bridge struc-ture.First,afinite element model corresponding to the target bridge is established based on ABAQUS software,and the load is controlled to simulate vehicle movement in each area of the traveling zone at different times.Sec-ond,the key cross-sections of segmental girder bridges are monitored in real time based on the force character-istics of continuous girder bridges,and they are compared with the simulation results.Finally,a material damage ontology model is introduced,and the structural damage caused by different overloading rates is compared and analyzed.Results show that thefinite element modeling method is accurate by comparing with on-site measured data,and it is suitable for the numerical simulation of segmental girder bridges;Dynamic sensors installed at 1/4L,1/2L,and 3/4L of the segmental girder main beams could be used to identify the dynamic response of segmental girder bridges;The bottom plate of the segmental girder bridge is mostly damaged at the position where the length of the precast beam section changes and the midspan position.With the increase in load,damage in the direction of the bridge develops faster than that in the direction of the transverse bridge.Thefindings of this study can guide maintenance departments in the management and maintenance of bridges and vehicles.
基金supported by the Natural Science Foundation of Zhejiang Province,China(Grant No.LD22E050003)the National Natural Science Foundation of China(Grant No.52222503).
文摘Automatic segment assembly,which increases boring efficiency and construction safety,is a trend in tunnel boring.However,the current situation still relies on manual operation and experience.Electro-hydraulic rotation systems are crucial in segment grasping,transporting,and assembly.This article presents the automation of rotation systems in segment assembly to improve motion smoothness and accuracy.As a result of strong nonlinearity and system complexity,parameter estimation is performed by using a noise reduction method based on multialgorithm fusion and the stochastic gradient deviation correction recursive least squares identification algorithm.Active disturbance rejection control(ADRC)is introduced into sliding mode control(SMC)to compensate for model uncertainty and disturbance.An improved cuckoo algorithm is used to optimize influential parameters in ADRC.Moreover,full-scale bench tests are conducted to verify the proposed system automation.Results indicate that the proposed method has a better displacement tracking performance and lower tracking error than the ADRC,SMC,and proportional-integral-derivative methods.Furthermore,such a procedure facilitates the success rate of complete segment assembly.
