| The arch with holes in web is becoming a focus of increasing interest in civil engineering field due to its beautiful configuration, less material and light weight. However, the existing theories and studies with respect to this kind of structure still lag behind the engineering practices because of the stress concentration around the holes, decrease of resistance to shear and complex buckling deformation et al.The state of the art of theory researches and practical applications highlights that it is significative to continue the work of predecessor to thoroughly investigate the variation laws of the ultimate load-carrying capacity and the deformation of I -section steel arches with holes in web.On the basis of the stability computation theory of structures and in consideration of material elasticity and geometrical nonlinearity, the 3-D finite element method is built by ANSYS software. By regarding the type of support, section size, holes diameter, holes number and arch height as different variables, the MAC file for whole computation process are formed, which provides the foundation for systemic analysis and computation.First, the eigenvalues of elastic steel arches with non-holes in web are computed, and the buckling load as well as buckling mode related to planar first unstable failure mode is determined for different restrictions and different loads.Then the ultimate load-carrying capacity and the vertical top displacement of elastic steel arches are computed for different restrictions, different loads and different section sizes.Thirdly, the variations of the ultimate load-carrying capacity as well as vertical top displacement of elastic steel arch with holes in web with different holes sizes, different number of holes and different section sizes are computed, and the law of ultimate load-carrying capacity as well as vertical top displacement variation in terms of the various influence factors are extracted by analyses, comparisons and curve fitting for all kinds of computation results.Fourthly, by the comparisons and analyses of global and local bulking deformations under the conditions of holes in web and non- holes in web, the conclusion is made that the variation of ultimate load-carrying capacity with width-thickness ratio(highness-thickness ratio) of section shows linearity or high-power polynomial relationships under distributed loads or concentrated loads at span midpoint, respectively. This conclusion is very useful for future same type structure designs and applications.
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