Research On Design And Monitoring Method Of Long Span Ice Shell Structure

As a new type of ice and snow structure,the large-span ice shell structure can form a single-layer closed space with high height and span.It has a crystal transluce nt texture and a beautiful free-form surface shape,and has high practical and artist ic appreciation value.Due to the strong creep properties and temperature sensitivity of ice materials,ice shell structure is prone to cracks,local collapse and local cavit y damage during service,which seriously affects the safety and applicability of the structure.In the past,the research on the response law of this structure only stayed at the observation level,lacking systematic design and monitoring research.In view of the high requirements of the building function of the large-span ice shell structure to accommodate the tourist activities,this paper starts from the two aspects of pre-design and post-maintenance,and guarantees its safety through structural analysis and monitoring means.On the above research background,this object has carried out some research works as follows:(1)The design method of large-span ice shell structure was studied by means of finite element simulation.The structural parameters provided by the unia xia l compression test of the composite ice material and the structural geomet r ic parameters provided by the architectural shape design document are used as the data basis.Referring to the load conditions during the service of the ice shell structure,the design is carried out in the finite element analysis software ANSYS.The ice shell structure is modeled and calculated.Based on the strength criterion of ice materia ls,and referring to the force performance analysis method of the free-form thin-s he ll structure,the over-limit and safety reserve of the main stress and displacement of the structure are investigated,and the thickness and shape of the structural design file are based on the verification results.Aspect adjustment to ensure structural safety and reasonable mechanical properties.(2)Based on the structural health monitoring theory,combined with the material properties and service characteristics of the ice shell structure,the strain,displacement,thickness and environmental factors including temperature and humidity were determined as key variables to be monitored in the service process of large-span ice shell structure.The method flow for monitoring the service process of large-span ice shell structure was designed.Based on the monitoring variables and monitoring methods,a data acquisition system suitable for the monitoring of the service process of large-span ice shell structure was developed,which solved the lowtemperature long-term work and transmission of the collection system.The three core problems of sensory equipment and ice material work together and data accuracy have initially achieved high-precision and high-efficiency ice-shell service data collect io n.(3)Using the above analysis method and monitoring system,the design and service period monitoring of the first air-bearing long-span ice shell structure “Snow Lotus” in China was carried out.Through design verification,the main parameters such as shell thickness and shape were determined.During the service period,the monitoring and analysis of the displacement and thickness of the key points of the structure were carried out,and the correlation law between the ambient tempera t ure and the sunshine condition and the ice shell structure response was qualitative l y understood.The displacement and thickness response of the ice shell structure with the temperature were preliminarily obtained.Presenting "segmented" features.Based on the monitoring results,the monitoring system was improved and improved,and the data accuracy and work efficiency were improved.(4)Using the analysis method and the improved monitoring system in the "Snow Lotus" case,the first air-ribbed long-span ice shell structure "ice and snow lecture hal " in China was designed and refined during the service period.Based on the work of "Snow Lotus",the design determines the weak points of the structure and increas es the high precision acquisition and analysis of the strain data.From the data level,the response change law and influencing factors of the ice shell structure service process were quantitatively explored.Finally,it is concluded that the safety monitoring of ice shell structure should focus on the changes of structural response when the temperature rises to-5 °C,which provides direction guidance for further research on the safety evaluation of ice shell structure.