P ‐Delta Analysis of Building Structures

The trend towards more slender and lighter building structures has resulted in potentially more significant P‐delta effects; this has led to the demand for simple and accurate methods of P‐delta analysis. Methods are reviewed and compared in terms of their efficiency and accuracy. Considered roughly in their order of sophistication, the methods reviewed include the amplification factor method, the direct method, the iterative method, the negative property member methods, and the second‐order computer program method. In addition to these, a new method similar to the iterative method, but based on analyses using the actual gravity loading applied to successive deflected shapes, is presented. The results are identical to those given by the iterative method, while the analysis takes less than one‐third of the time. Factors that differentiate the methods include their accuracy, ease of use, whether they are for hand or computer use, and whether they are applicable to all types of structures or only to certain types.