| High-voltage transmission lines are important lifeline projects,it is of great significance to improve their economic efficiency under the premise of ensuring safety.The transmission tower structure has the characteristics of high towering and high flexibility,and its natural vibration period is close to the remarkable period of seismic action.Research on the seismic performance of the transmission tower structure,especially the optimized transmission tower structure,is of great significance to ensuring the transmission lifeline project.At present,the optimal design of transmission tower structure lacks comprehensive methods suitable for engineering design and application.At the same time,the seismic evaluation of transmission towers is mainly based on traditional seismic analysis methods,which cannot reflect the damage state of the structure under different intensity levels of earthquakes.To this end,the thesis carried out optimized design and optimized seismic performance of the transmission tower structure for the transmission tower structure.The main contents are as follows:1.Based on the idea of stepwise design and full stress criterion,a "stepwise optimization method" for the structure of the transmission tower is proposed.The method is used to optimize the design of the 220 k V linear tower 2E11-SZC2,The weight of the transmission tower was reduced by 24.5%,the overall shape is optimized to reduce the weight by 20.8%.The results show that this method can achieve better optimization results,and the overall shape is more obvious than the optimization effect of local internodes.2.In order to verify the reliability and safety of the optimization results,the optimized transmission tower was tested in real form,and an ABAQUS analysis model was established using appropriate methods.The accuracy of the model is verified by comparing the observation point displacements and weak parts of the numerical simulation and test results,which lays the foundation for static elastoplastic analysis and seismic vulnerability analysis.The results show that the beam element and rigid node modeling can meet the requirements of the transmission tower node constraints;the influence of the gusset plate on the ultimate bearing capacity of the compression-bending member cannot be ignored,and the length of the gusset plate is used as the calculated length to calculate the length..3.Perform pushover analysis on the optimized transmission tower structure,compare the influence of the four types of lateral loads on the pushover analysis,it is recommended to select exponential distribution,inverted triangle distribution and SRSS distribution lateral load for Pushover analysis.4.Established a performance-based seismic damage evaluation method for transmission tower structures.Taking the displacement of the tower top as the structural performance control index,the seismic damage state of the transmission tower structure is divided into five levels: basically intact,slight damage,moderate damage,severe damage and close to collapse,and the limit state of seismic damage at all levels is quantified.5.Use the probabilistic analysis of seismic vulnerability analysis method based on the incremental dynamic method to evaluate the seismic performance of the optimized transmission tower.Performed IDA analysis on the optimized transmission tower structure,establish a probabilistic seismic vulnerability analysis model based on the limit state of seismic damage at all levels,and evaluate the seismic performance of the optimized transmission tower from the perspective of probability. |
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