چکیده:
The aim of this study is testing of nonlinear static analysis method for seismic evaluation of bridges. So, the application of the mentioned method was evaluated about three bridges with different openings and irregular piers (bases). In addition, the effect of the number of middle piers (bases) in the numbers of effective modes in seismic evaluation of bridges was assessed. According to the results, the effect of higher modes in modal pushover analysis increases by increasing of the bridge opening length and the numbers of middle piers (bases).
خلاصه ماشینی:
According to the results, the effect of higher modes in modal pushover analysis increases by increasing of the bridge opening length and the numbers of middle piers (bases).
2002 ; Aydin oğlu 2003 ; 2004 ; Antoniou & Pinho 2004) Modal pushover method will be represented in the consequent stages (briefly) in the following way (Pinho & et al , 2006) : Accomplishment of special analysis for determination of natural periods of vibration and modal shapes of structure Accomplishment of pushover analysis for each mode with load distribution pattern and determination of base shear curve of the relevant displacement The idealization of pushover curve in the form of two- line curve (figure 3) The calculation of maximum transfiguration in nth inelastic mode The maximum estimation of control point displacement, relevant to nth inelastic mode Figure 3 : The idealization of pushover curve in the form of the two- line curve The Materials and the Methods Modeling In this study, three examples of concrete bridges with different structural system have been used for assessment and inspection of the effect of the numbers of openings in the height of bridge piers (bases) on effective mode numbers in nonlinear static analysis.
1. The modal characteristics as well as the maximum of deck displacement in the place of middle piers (bases) have been brought according to single-mode pushover analysis and dynamic analysis of time history in tables 2, 3 and figure 9.