Measurement And Research For Surface Wind Presssure On The Steel Box Girder Of Large Span Bridge

For the sake of obtainning the first hand data of pressure values and thedistribution of the streamlined section. A few wind pressure sensors are mounted at thegirder including, the deck, the wind fairing and the beam bottom parallel to the crosssection in the mid-span of Xia Zhang bridge to record the wind pressure data.The history and research status of the wind-resistance of bridge and wind pressureon the steel box girder all over the world are introduced and summarized first. Then asummary and analysis of the measurement and research for the wind pressure on thebuilding is done, especially, the wind pressure of the steel box girder. An arrangement ofthe natural wind properties is made as well as the static effects and vibrational effectsand the basic situation of the XiaZhang Bridge. It describes the design scheme of themeasured system. And a lot of experiments and corrections have been done to determinethe best scheme. The various parameters and quantity of the pressure sensor and datacollector are introduced as well as the layout scheme, the installation and the acquisitionmode of measured system.It records the wind pressure data in good weather conditions. It analyzes the windpressure values and distribution during the different wind direction, wind speed, windattack angle and wind deviation angle. The results show that the speed and pressure arein a positive correlation, the wind attack angle is the main factor of the distribution, thewind deviation has little infuence to both of two. Making a comparison with windpressure of the different duration, there’s an anticorrelation between pressure values andduration. And there has no clear geometric relationship to do a research at the samepoint. The distribution of the wind pressure in vibrational state is similar to the static.The distribution of the wind pressure can be explained well by using the BernoulliEquation and Boundary Layer Theory. Compared the pressure of wind tunnel withmeasurement, there is a great similarity between them. And both of two can vividlydisplay the effect of wind on the bridge. Calculating aerodynamic coefficients, there is agreat similarity about the calculation of drag coefficient between measurement and windtunnel but the lift coefficient and torque coefficient. This is because the measurementdoes not consider the wind pressure on the traffic lane.