Study On The Shape Coefficient And Wind-resistant Properties Of Open-style Arched Corrugated Steel Roof

ABSTRACT:Due to the small self-weight, small stiffness and low natural vibration frequency, Arched Corrugated Steel Roof (ACSR) is very sensitive to wind loads. The shape coefficients of wind load and wind-induced response are key problems in the wind resistant design of open-type ACSR. At present, there are no relative standards and codes at home and abroad, and the related literatures are still rare so far. Because of lacking the necessary technical support, wind-induced damages happen sometimes. So, it is urgent to carry out systematically wind resistant research of such structure. In this paper, open-type ACSR's shape coefficient and wind resistance are analysised and simulated by employing numerical method, the research content is listed as follow:1. Characteristics of wind are represented. Average wind is introduced fully and its calculation method in load code is mentioned. At the same time, this dissertation figures out the dynamic effect of fluctuating wind, turbulence intensity and fluctuating wind spectrum.2. On the basis of former research achievement, the numerical discrete form of averaged Navier-Stokes equation for turbulent wind flow is established and its discretization form and method are given. Then, advantages and disadvantages of different kinds of turbulence models are explained. Based on the above mentioned theory, shape coefficient of single-span closed-end floor type arch roof is analysed and the results are compared with "Building Structural Load Code", which verify the reliability of this method.3. Numerical wind tunnel simulation is operated on ACSR in RNG k-s turbulence model by CFX program. Firstly, discuss and obtain column height and column spacing's influence on the wind pressure distribution on the roof; then select three other parameters such as span, rise-to-span ratio and length-to-span ratio and adopt orthogonal test of three factors and three levels for the study, get the parameter has significant effect on the wind pressure distribution and shape coefficient; finally gives out the suggestion values of the such roof's shape coefficient.4. Wind-induced dynamic responses of ACSR are studied in frequency domain. Firstly, describe the random vibration theory; then, from the analysis, the wind vibration coefficient is got and displacement response power spectrum density is also gained. In the part, the shell model is employed in the ANSYS to simulate the structure; the PSD method is used to calculate the dynamic responses.5. Wind-induced dynamic responses of ACSR are studied in time domain. Digital simulation of fluttering wind is worked out in matlab, which can create wind velocity time-history data considering stochastic nature, time correlation and spatial correlation.Then, the TRANS method in the ANSYS is used to calculate the dynamic responses in time domain to compare the results with those in frequency domain in order to verify the validity of the two methods.