Study On The Design Theory Of High Pier

In recent years, with the rapid development of highways in our country, highways of higher grade are being built in mountainous area. Bridges with high pier are unavoidable in some special districts. Different from the ordinary piers, high piers are always flexible, and extra factors must be considered when designing high piers.In this article, based on extensive investigation and plentiful references, the author introduces the section types of high pier that we usually use, and then it gives a general rule about how to choose the section type of high pier according to its height.How to decide the effective length of the pier is always a problem which puzzled bridge designers. This article associates stability analysis with the Euler formula, and gets the effective length coefficient by comparing the stability coefficient of the whole model and the pier model. Then we can calculate the reinforcement of the pier exactly by the correct effective length.Different from ordinary pier, high piers are always flexible. And the displacement must be calculated specially, by considering the effect of geometric non-linearity. This article uses the Rayleigh-Rize method to get the displacement of high pier. And compare its results with that generated from ANSYS. Results indicate that Rayleigh-Rize method can take the effect of geometric non-linearity into account. By contrasting Rayleigh-Rize method with that doesn't consider the geometric non-linearity, we get the conclusion that if the slenderness ratio of the pier exceeds a certain value, the effect of geometric non-linearity must be considered.High piers always adopt the sections which have thin walls, stability analysis is very important for this kind of piers. This article discusses the difference of two stability analytical methods; suggests that high pier adopt the second type of stability analysis. Then by calculating the strength,the displacement and the stability coefficient of the pier of different heights, the author find that displacement is the controlling factor in high-pier's design. Based on the sufficient consideration of strength and stability, it's necessary to extend the displacement limits when designing high piers.Hollow thin pier is one of the most widely used types of high pier. Temperature effect has great influence on this type of pier. In this article, the temperature effect caused by hydration heat is analyzed at first, and temperature distribution and stress distribution is carried out through the construction simulation of the pier. Moreover, this article simulates the reaction of high pier under solar radiation. And through the simulation analysis, the temperature distribution and stress distribution can be carried out, with the displacement be solved either.