12. Pushover


The 12nd option in the RM Bridge Enterprise Training Examples, 12. Pushover has the datasets and a description document for modeling and analysis of a Pushover  bridge structure. It can be accessed at File\Examples\Training Examples by selecting 12. Pushover as shown below.

Tr   Pushover

Users can load either the finalized Modeler example (and finish the input as in the document) or the Analyzer complete example for understanding the philosophy. The pushover example has a description document including a theoretical background in the .pdf format. It can be accessed in the Description button, as shown below. The example and documentation show the procedure for performing a dynamic earthquake calculation using Pushover Analysis with all necessary steps including Load Case definition, preparation of RM-Sets diagrams, and Calculation actions in the schedule for Pushover:

  1. Definition of masses of all permanent loads (i.e. self-weight and superimposed dead load);
  2. Calculation of the eigenvalues;
  3. Preparation of RM-Set for pushover analysis;
  4. Definition of the actions:
    1. PushOver: to generate the Capacity curve, and;
    2. PushOverD: Generate the Demand curve;
  5. Result presentation.

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The Pushover analysis in this example is in SI units and it's based at the Eigen natural frequencies, the Response Spectrum, and a displacement control as the type of increment. The number of Eigenvalues that need to be calculated can be found by listing the Mass Participation Factors and verifying the sum in the respective direction, in this case, the horizontal plane of the Global axis X and Z. Initially we generate the Capacity Curve in each direction with PushOver action and then the Demand curve with action PushOverD using either EC8 or FEMA440 according to the Equivalent Linearization and Displacement modification. In general, under lateral loads, non-linear behavior may occur in the pier segments and the user might need to define an adequate amount of reinforcement to the piers. The plots below show the final results for Capacity and Demand vs Capacity for this simplified seismic method:

PushoverC   PushoverDC