Study On The Earthquake Effect And Seismic Design Method Of Few Walls SRC Frame Structure Of Main Powerhouse In Large-scale Thermal Power Plant

At present,thermal power is an important component of china's electricity, which accounting for about 80% of the total generating capacity. Even in the future, while nuclear power, hydro power and wind power will developing vigorously, thermal power will still account for a large proportion. Power structure is an important industrial buildings in lifeline engineering, the safety of the power structure is significant. Subject to the process constraints, the arrangement of the main powerhouse in thermal power plant is complex, spatial intergral performance of the structure is poor. At the same time, it with more weaknesses, low emergency capacity, insufficient durability. So, it's very important to find a new type of main powerhouse that can be used in high seismic intensity region and with good seismic performance and relatively low cost.In this paper, few reinforced concrete shear walls steel reinforced concrete frame hybrid structure is proposed be used in thermal power plant at the first time. Furthermore a hybrid structure of main planthouse with 1000MW units is taken as a research object, theoretical analysis and experimental study are used to research the key technical issues of this kind of structure in seismic design. Analyzed the dynamic properties and torsion reaction influencing factor of the the main powerhouse; predominated the inner force distribution regularity and the collaborative work capability of the structure under seismic action; used model structure test to the earthquake-resistance performance and stiffness degradation rule of the structure, conducted structural dynamic elastic-plastic time-history analysis on structure with ABAQUS software, established performance design methods based on internal objects using the basic principle of performance design; proposed the reasonable structural seismic design method and construction measures of main powehouse structure.(1) The irregularity and torsional effect of the main planthouse are analyzed by using SAP2000 finite element software. The results show that torsional effect of the structure is obvious and coupling effect between the modes is significantly. By analyzing the dynamic properties of the hybrid structure of the main powerhouse, an effective control measure is recommended to reduce the structure's torsion reaction.(2) Taking into account the irregularity of the structure, lateral-torsional coupled earthquake response analysis is used to understand the deformation characteristics, load transfer mechanism inner force distribution regularity of the structure under seismic action. Based on the existing research results, irregular structure's seismic effect calculating method is proposed to improve the seismic performance of main powerhouse in thermal power plant. At the same time, coordinated working capability of the structure under seismic action is studied to put forward the reasonable number of the RC walls and controls index of the storey drift.(3) Due to the limited of the laboratory conditions, a three-bay and three-span sub-space model with 1/7 scaling factor is made, and seismic performance test (pseudo-dynamic test and pseudo-static test) is carried out to study the emergence and development law of the cracks, deformation capacity, stiffness degradation rule, structural failure mode, energy dissipation capacity and weak parts of the model structure. The results show that rational designed main building structure can meet the requirement of the 3-level sesmic design target.(4) By using ABAQUS software, structural dynamic elastic-plastic time-history analysis is carried out to verify the deformation and weak parts of the main powehouse under different intensity earthquake. The results show that the arrangement of shear walls increased the lateral stiffness and improve the seismic performance of the main powehouse structure. Under strong earthquake action, shear walls bear most of the earthquake force, destruction of shear walls delayed the destruction of the frame sub-structure. The collaborative work between SRC frame and shear wall can achieve the design objective of two earthquake fortification line.(5) Internal equipments and process pipings are the service object of main powerhouse structure, based on the limit state that determined by structural designers and process designers, displacement-based seismic method is established to improve the seismic design method of main powerhouse in large-scale thermal power plant. Taking into account the structural members, non-structural members and performance of the major equipments within the main powerhouse, main powerhouse structure's seismic performance is divided into five levels:serviceability, continue use, life safety, collapse preveniion and collapse, this five levels are quantified with storey drift ratios. During structure design, the relationship between ductility and reinforcement of the structural members is established to ensure the structure can resist different intensity earthquake force.(6) Based on the experimental research and theoretical analysis results, comprehensive consideration engineering practice at home and abroad and China's actual situation, reasonable structural seismic design method and construction measures of main powehouse structure is proposed, and these studies can be used as reference materials to establish the relative code.