The Analysis On Comfort Degree Of A Long-Span Public Building

Abstract:The form of building structure becomes more and more complex with the development and progress of economy and technology. Also the span of beam slab is becoming longer and longer. Coupled with the application of high-strength and light-weight materials, it makes the building structure develop into multi-direction, light-weight and long-span. So the decrease of stiffness leads to the similarity of natural frequency of vibration and frequency of human activity. As a result, these buildings may produce more obvious vibration under pedestrian forces and then affect peoples’comfort feeling.This paper takes the Riverside Concert Hall of Changsha for instance and proceeds the dynamic response analysis under different load applied in the first to the third storey, then evaluating its comfort. The purpose of this research is to analyze large-span floor’s dynamic response under different load conditions and summarize the existing literature to get the calculation methods of different dynamic response and the standards of comfort evaluation. As a result, the comfort of the structure is evaluated. The main research results are as follows:(1) The paper establishes the model of the structure based on the large general finite element software Midas/Gen. Various single loads and crowded loads are analyzed of the vibration response, and different ways of loading are considered. According to the analysis results, vibration is slightly weakened on the three control points loading than on a single control point. However, since the overall stiffness is very strong, the extent of weakening is not significant.(2) The paper also considers the effect of lateral force load, and compares the results of dynamic response between loading vertical force and lateral force at the same time on the three control points and loading only vertical force at the same points. According to the analysis results, the peak acceleration response of the former situation is about3times of the latter situation, which means that the impact of lateral force is relatively Significant. (3) In addition, this paper extracts the models of the first,the second and the third floor from the whole model, and carries on the dynamic response analysis under the load of single pedestrian. The results obtained are compared with the results of the whole model, and it shows that vibration response under the single board is bigger. It also illustrates the importance of vibration analysis on the whole model.(4) Combined with the Technical specification for concrete structures High-rise building (JGJ3-2010), the paper analyzes the comfort evaluation of the structure under the index of peak acceleration. According to the analysis results, the comfort meets the requirement of specification under the single pedestrian load, while it can’t meet the requirement under crowded force. In addition, the annoyance rate is evaluated as the second evaluation index, and the conclusion is basically identical with the above evaluation result.(5) Finally, the paper analyzes the effect factors of structural vibration, including the thickness and the damping ratio. The result shows that the response peak acceleration decreases with the increase of thickness under pedestrian forces, but the decrease amplitude is not big. Also, the vibration response increases with the increase of damping ratio, and the decrease amplitude is gradually eased. The peak acceleration reduces69.03%from the damping ratio of0.05to0.01, which means that the decrease amplitude is relatively big. In practical engineering, the structural vibration response is weakened by increasing the damping ratio, including increasing the un-structural wall, installing TMD and so on.