Study On Seismic Performance Of Steel Frame Structures With Viscoelastic Dampers

The frequent occurrence of earthquake disasters not only seriously threaten the lives and property safety of people in the world, but also give them a great panic in spirit and psychology.As a sudden and devastating natural disasters, the moment of the earthquake may destroy a modern city seriously, which makes the seismic design of building structures become particularly important.In the face of the earthquake disaster, human can not control. The only way to enhance the building’s ability to resist earthquakes is to use a variety of anti-seismic measures. Make sure to reduce the casualties and property damage caused by the earthquake as much as possible.Traditional seismic design is a method of using the bearing capacity and deformation capacity of the structure to resist the earthquake. This method lack of self adjustment ability and it may not meet the requirements of safety under the uncertain earthquake. In case of meeting the design requirements, the size of the structural components may be very large, so that the layout of the construction is difficult, but also increased considerably in the economy. However, the energy dissipation design dissipate or absorb seismic energy by design some components of the structure as energy dissipation component or install some dampers in some parts of the structure. Under wind load and small earthquake, the energy dissipation component and dampers are in elastic state to ensure that the structural system has enough anti lateral stiffness to meet the normal use. Under the strong earthquake, the energy dissipation component or dampers enter the non elastic state firstly, and thus the main structure is protected from damage.1. Viscoelastic damper is a kind of passive damping device. This paper introduces the basic structure and working mechanism of viscoelastic dampers at first. Then introduce the fractional differential models, which is used to calculate the force of viscoelastic dampers. List the parameters required according to the fractional differential models and the numerical calculation method in this paper.2. The energy dissipation characteristics of viscoelastic dampers are mainly influenced by temperature, frequency and strain amplitude, the same as viscoelastic material. Write a corresponding computer program according to the numerical calculation method of fractional derivative model. Change the temperature, frequency and strain amplitude in the program respectively and calculate the storage stiffness, loss stiffness, loss coefficient according to the hysteretic curve. Discuss the effect of three kinds of related factors, which is used to evaluate the softening characteristics and the energy dissipation ability of viscoelastic damper.3. Define the structure without being added viscoelastic dampers as the original structure and the structure added viscous dampers as the energy dissipation structure. Establish a model of single layer structure and calculate both the structures’ seismic response under a variety of earthquake actions by using the elasto-plastic time history analysis program respectively. After getting the displacement response and acceleration response, calculate the reduction ratio of the peak of displacement and the acceleration. According to the energy balance equation, discuss the energy absorption of the original structure and the energy dissipation structure. By careful comparison and analysis, the displacement response and acceleration response of the structure were reduced obviously after being added viscoelastic dampers. That is to say, viscoelastic dampers have good performance of reducing seismic response.4. A 12-story steel frame structure model is established and its restoring force characteristic is calculated. Write the elastic plastic time history analysis program of two kinds of structures according to the vibration differential equation of the original structure and the energy dissipation structure, which is based on the fractional differential method. Calculate the seismic responses under a variety of earthquake actions and compare the energy distribution.5. Do some reach on the viscoelastic dampers with different layout methods and delivery which is aimed at getting and verifying the relevance between the delivery and the story. The results show that the viscoelastic dampers not only have good shock absorption effect, but also can confirm the delivery using the relevance above which guarantee the structure to reach a optimum state.