Pushover Analysis of Multi Storey Building Using Etabs
Procedure of Nonlinear static pushover analysis in SAP2000 1. Defining hinge properties
The very first step in pushover analysis is defining the hinge properties. Hinge properties are section dependent. Thus it would be necessary to define a different set of hinge properties for each different frame sections type in the model. To simplify this process, the concept of default properties is used in SAP2000. When default properties are used, the program combines its built-in default default criteria with with the defined section section properties for for each element element to generate the final hinge properties. The default properties cannot be modified and can only be viewed. We used the built-in default hinge properties based based on FEMA-356 FEMA-356 criteria. Hence Hence there is no need to define hinge properties for any section. The default hinge properties are symmetric
2. Assigning hinge properties
The next step in pushover analysis is assigning hinge properties. Multiple hinges can be assigned at a single point. We have assigned the following hinge properties to the each section of the frame model. Default PMM hinges to each end of the frame column. Default M3 hinges to each end of the beam Hinge properties to the columns are assigned in the following steps a. Assigning hinges to columns Select>>properties>>frame section and In the select menu go to Select>>properties>>frame select the column sections to which you want to assign the hinges. Click ok In the assign menu go to frame>>hinges. Click the add button. Select from the drop down list the auto-hinge type from the table of FEMA-356 and select a FEMA-356 table as table 6-8 Relative distance is measured from the I-end of the beam, and is based on the clear length between rigid rigid ends offset. offset. A “0” relative relative distance indicates the hinge is at the I-end of the beam. beam. A “1” relative distance indicates the hinge is at the j-end of the beam. Hinges may be located anywhere along the length of the beam.
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Fill the rest of auto-hinge assignment data as depicted in the figure and click OK. b. Assigning hinges to beams In the select menu go to Select>>properties>>frame section and select the sections to which you want to assign the hinges. Click ok In the assign menu go to frame>>hinges. Click the add button. Select from the drop down list the auto-hinge type from the table of FEMA-356 and select a FEMA-356 table as table 6-7. Relative distance is as defined while assigning hinges to columns. Fill the rest of auto-hinge assignment data as depicted in the figure and click OK. Defining non- linear load cases Setting pushover parameters Running analysis Displaying pushover plots
