Studies On The Second-order Effect Of Structural Design Of The Reinforced Concrete Chimney In The Large Thermal Power Plant

The reinforced concrete chimney is an important project in industrial buildings, which is a typical high-rise structure, and it is sensitive to P-Δeffect caused by horizontal displacement. With the development of modern industry, the chimney is more and more high which make us pay more attention on the P-Δeffect of chimney. In despite of the research about second-order effect of structure has made great achievements, but the analysis about second-order effect of chimney remains to be clarified in the process of chimney design, and need to do further research.This paper which analyze and summary the measures of second-order effect of reinforced concrete structure, and focus more attention on the analysis of P-Δeffect of high-rise structure. Considering the impact of P-Δeffect, derive the reasonable chimney design formula on the basis of energy method, and go into the specific calculation of inter forces and deformation. By using the Castigliano's first theorem and minimum potential energy principle, the apical displacement and additional bending moment at the bottom and moment magnification coefficient of chimney can be obtained when the chimney under the action of wind load. Figure out the bottom additional bending moment under wind load based on criterion of chimney design, and compare the difference of results which derive from the two approaches. By comparison, the reasonable value of chimney stiffness reduction coefficient can be achieved. Compare the two results derived from criterion of chimney design and energy method when consider stiffness reduction into account.Based on nonlinear static analysis method, carrying on chimney pushover analysis by SAP2000, and obtain the load-displacement curve and the Integral deformation curve of chimney. Compare curves derived from analysis with curve of shape function of energy method, and by compare to see if they consistent or not.Doing the finite element analysis of chimney with the height of 240m by SAP2000, the apical displacement and situation of internal force distribution under different stiffness reduction coefficient can be gained. By compare the apical displacement value and stress distribution under different stiffness reduction coefficient, selecting a reasonable stiffness reduction coefficient and making the achieved result consistent to result derived from standard of chimney design and energy method.