Question

Which lateral load pattern used in pushover analysis typically results in a higher base shear compared to other patterns for the same target displacement?

Accepted Answer

A uniform lateral load pattern in pushover analysis generally results in a higher base shear *early in the pushover analysiscompared to other commonly used patterns like triangular or modal patterns when aiming for the *same initialtarget displacement. Pushover analysis is a static nonlinear analysis used to estimate the force and deformation demands on a structure subjected to earthquake ground motions. A uniform load pattern applies a lateral force proportional to the mass at each story level. Since it applies force to all stories equally (relative to mass), it engages more of the structure&#x27;s elements simultaneously at the beginning of the analysis. This wider engagement initially requires a higher base shear to initiate yielding and achieve a certain displacement, compared to patterns like triangular or modal, which concentrate force higher in the structure. However, as the structure undergoes significant nonlinear behavior and forms plastic hinges, the relationship between the load pattern and the base shear at a specific *largetarget displacement becomes more complex and depends on the structure&#x27;s specific characteristics and the sequence of hinge formation. Therefore, the statement holds true primarily in the *initial stagesof the pushover before significant yielding occurs.

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Which lateral load pattern used in pushover analysis typically results in a higher base shear compared to other patterns for the same target displacement?