Fatigue Reliability Study On Details Of Steel Box Girders Of Ping-sheng Suspension Bridge Based On Monitoring Data

In the operating period again and again under the action of vehicle load, facing the fatigue damage of bridge structure. Considering the randomness of the structural parameters and load, the fatigue damage of bridge structure has the characteristics of a certain probability. As the largest span of the anchor box girder suspension bridge-ping-sheng bridge structure fatigue reliability of the orthotropic bridge deck is worth for safety assessment. Regard by the bridge has been installed health monitoring system, the system can provide fatigue stress of steel panel data, the panel of ping-sheng bridge steel box girder bridge fatigue reliability assessment provides favorable conditions. To study a long-span self-anchored suspension bridge steel box girder of type structure detail fatigue reliability under random load, with the largest span suspension bridge of single tower from anchor-ping-sheng bridge as the engineering background, stress in health monitoring data on the basis of the fatigue reliability theory is adopted to details of the steel box girder bridge panel structure fatigue performance is studied. First linear cumulative damage criterion is established based on Palmegren-Miner fatigue reliability of the limit state equation, the second is based on typical of ping-sheng bridge health monitoring data stress and temperature fatigue stress spectrum is established, and finally analyzes the ping-sheng bridge steel box girder under different traffic growth factor detail fatigue reliability. Paper the main research contents and research achievements include:(1) Steel structure fatigue reliability theory are briefly discussed and the corresponding analysis method. By s-n curve and Miner linear damage rule as the foundation, to establish the limit state equation of fatigue damage and fatigue reliability assessment of the key steps is given. Mainly from the structural reliability theory and its analysis method, the fatigue property of steel box girder, and fatigue reliability evaluation method is discussed in three aspects. For fatigue reliability analysis of the limit state of expression, this paper introduces the important structure of the JC method of reliability analysis, the method for later lay the foundation for fatigue reliability index calculation. From the fatigue performance of steel box girder structure, steel structure fatigue failure limit state equation, the three important fatigue failure criterion is discussed. From the current fatigue reliability evaluation methods were reviewed in this paper the fatigue reliability assessment flow chart.(2) To the fatigue stress of ping-sheng bridge health monitoring system are analyzed in statistics. Pingsheng bridge health monitoring system are introduced, and the ping-sheng bridge health monitoring of the entire system and sensor layout two aspects are described. By introducing the rain flow count method and gu-feng introduced two methods of monitoring the stress data extraction force and analysis method. With the processing of measured data in analysis, extract the stress cycle and cycle times, and multiple sets of stress data for statistical analysis.the probability model of ping-sheng bridge fatigue load effect is established. The K-S test to obtain the probability distribution types and distribution of Seq and Nd eigenvalues. By the analysis results indicate:the span across BCV5-2 sensor location of fatigue damage, the largest Seq averages 5.31 MPa, the standard deviation is 1.58 MPa, for it damage value of 1.3×106.(3) In order to study fatigue reliability of steel girders of self-anchored suspension bridges under random loads, Ping-sheng Bridge, which is the longest self-anchored suspension bridge with single tower, is selected to be an engineering project. The fatigue reliability of this bridge is studied using fatigue reliability theory and structural health monitoring data. The limit state functions of fatigue reliability are established according to the Palegren-Miner linear damage rule. The stress and temperature spectrums are modeled based on structural health monitoring data and fatigue reliability of details of steel box girders of Ping-Sheng Bridge are calculated taking different traffic volume into considered. Numerical studies show that:the stress data of steel box girder of Pingsheng bridge process a low stress and high cycle peculiarity. The equal steel amplitudes can be calculated by Erucode and equal damage rule. If the growth factor of traffic volume is taken as 0,0.1 and 0.2, the fatigue reliability index is 2.305,1.861 and 1.395, respectively. The growth factor of traffic volume has a low-impact to the fatigue reliability in the early years, but on the contrary in later years.