Linear and Nonlinear Static Analysis of High-Rise Buildings Under Wind Load Using Direct Analysis Method

This study concerns with the investigation of P-Delta effects on tall steel buildings. After reviewing the different structural systems of tall buildings, bundled tube system was selected for its ability to resist lateral loads for all commonly used height ranges, including those considered in this research. Five building models ranging from 10 to 50 stories were modeled and analyzed linearly and nonlinearly using ETABS. All models are square in plan with an area of (36m 36m), and a fixed story height of (4m). all models were braced in the along wind direction only with an X-brace system. Static wind load as per ASCE 7-10 is applied to the structure as the main lateral load. After analysis, a comparative study was presented with respect to two analysis methods (Amplified First Order and General Second Order Method), the comparison incorporated top displacements, maximum drifts, base shears and base moments. The study reveals that General Second Order method should be used for tall buildings since it yields larger values than Amplified First Order method, also P-Delta analysis is significant for buildings higher than 20 stories.