Probability Model Research On Resistance Of Cable-stayed Bridge During Construction

With the rapid development of transportation construction, concrete cable-stayed bridges are more and more, while average risk during construction is more than that in service. So the research on resistance during construction is important.The main factor of resistance during construction is the early mechanical properties of concrete. On the basis of spot sample and laboratory experiment, this paper studies the early mechanical properties of concrete. Probability distributions of early strength and elastic modulus of concrete .are set up. Time-variant models of mean and variation. coefficient of early strength and elastic modulus are developed respectively. Also the relationship between the early strength and elastic modulus of concrete is developed.The two methods of calculating the standard auto-correlation function are introduced: the method of discreteness data and the method of continue function assuming resistance belonging to independent increment random process. According to the two methods, the values of standard auto-correlation function of resistance during construction are calculated respectively, and it is found that auto-correlations of resistance during construction are stronger, and the values of the standard auto-correlation function based on assuming resistance belonging to independent increment random process are less than the results of on discreteness data. If enough accurate and much data are obtained, the latter can reach enough requirement. The values of the standard auto-correlation function based on assuming resistance belonging to independent increment random process are less than the accurate results.The concept of "construction target period " is put forward. The difference between construction and service period is discussed. Considering the characters of construction period, the probability models of mean and variation coefficient of early resistance for flexural member of cable-stayed bridge are set up. The sensitivities of the parameters which can influence the resistances are also analyzed, and it is found that variation coefficient of early resistance during construction is larger, and the influence of early strength of concrete on variation coefficient of resistance during construction is the most. So it is strictly controlled during construction. The influence of the uncertainty of reinforcement strength on variability coefficient of resistance is the least. So it can be as...