Study On Calculation Method Of Medium Thickness Steel Reinforced Concrete Pier

Steel reinforced concrete pier is a new kind of pier structure,replacing steel bar in conventional reinforced concrete pier with steel.The previous study found that compared with the conventional reinforced concrete pier,it significantly increases the bearing capacity of the pier,which makes it more suitable for the high head and large thrust pier.Compared with prestressed pier,steel reinforced concrete pier has more advantages in construction,so it has a great value of engineering application.The bearing capacity of steel reinforced concrete is closely related to the amount of steel and the arrangement form of steel.Therefore,the research on the reasonable amount of steel and the arrangement form of steel in the steel reinforced concrete pier,and the research of the calculation method of the steel reinforced concerete pier can provide theoretical guidance for the application of the steel reinforced concrete pier in water conservancy and hydropower projects.In this paper,the formula for calculating the amount of steel in the steel reinforced concrete pier is put forward according to the formula of calculating the amount of steel bar in conventional steel reinforced concrete pier,and given the formula one undetermined coefficient.A typical middle thickness steel reinforces concrete pier model is established,based on the analysis of the displacement,stress,crack distribution and bearing capacity of the pier under different quantity steel,the reasonable quantity of steel in pier is obtained.At the same time,accroding to the definition of steel ratio in steel concrete column,the definition of section steel ratio in steel reinforced concrete pier is put forward.By presenting formula of calculating the amount of steel in the pier and the range of the section steel content,the calculation method of the steel quantity in steel reinforced concrete pier is established by combining the thrust of the gate and the section size of the pier.The analysis shows following conclusions:(1)For the same type of steel arrangement,under various load conditions,in a certain range,with the increase of steel amount,the stress and displacement of pier concerete and the stress and displacement of shape steel gradually decrease,the range of tensile stress distribution of the pier decreases,crack resistance ability,bearing capacity and ductility of the pier all gradually increase.(2)Under symmetric load,when the steel in pier is single steel arrangement,the recommended ranges of the ?1 coefficient value is 1.2??1?1.4,the required amount of shape steel is greater than steel bar in conventional reinforced concrete pier;when the steel in pier is three steel arrangement,the recommendes ranges of the ?1 coefficient value is 0.8??1?1.0,the required amount of shape steel is less than the steel bar in conventional reinforced concrete pier.(3)Under unsymmetric load,when the steel pier in single steel layout,the recommended ranges of the ?2 coefficient value is 1.3<??2?1.4,the required amount of shape steel is greater than steel bar in conventional reinforced concrete pier;when the steel pier in three steel layout,the recommended ranges of the ?2 coefficient value is 0.7??2?0.9,the required amount of shape steel is less than the steel bar in conventional reinforced concrete pier.(4)Under the symmetrical load,the scope of section steel content in middle thickness steel reinforced concrete pier is 0.6%??a?1%;under asymmetric loads,the recommended range of section steel content of middle thickness steel reinforced concrete pier is 0.7??a?1.3%.In general,the recommended range of section steel content of middle thickness steel reinforced concrete pier is 0.6%??a?1.3%.(5)Under the same gate thrust,compared with one-steel reinforced concrete pier,three-steel reinforced concrete pier need less amount of steel,which makes it more economic.In the same amount of steel,three-steel reinforced concrete pier has better force performance and higher capacity than one-steel reinforced concrete pier.So,it is recommended to adopt three-steel reinforced concrete pier in practical engineering.