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Arch wall is a vertical plane structure which combines pure arch, columns and beam together. The applied in-plane vertical loads on the beam will reach the large span arch through columns. For studying the stability of arch wall, the elastic and inelastic mechanical properties of arch wall were discussed in this paper by finite element method. It is shown that lateral bracing stiffness of beam and column stiffness are the key factors which affect the stability of arch wall: if the lateral bracing stiffness is less than its threshold stiffness, the arch wall shows a global out-of-plane buckling mode; if the bracing stiffness is greater than its threshold stiffness and column stiffness is less than its threshold stiffness, the pure arch shows an out-of-plane buckling mode; if both of the bracing stiffness and column stiffness are greater than their threshold stiffness, the arch wall shows an in-plane buckling mode. After that, two analytical models of arch wall from a practical engineering structure were proposed for predicting the ultimate out of plane strength of arch wall. One analytical model reflects only the arch wall laterally braced by equivalent lateral spring resulting from lateral trusses, and the other is a combination of arch wall with longitudinal trusses. The result points out that the lateral bracing stiffness of beam supplied by longitudinal trusses is much larger than the threshold stiffness, the bearing capability of arch wall can be improved only by increasing the stiffness of column or strengthening the reliable connection of column ends. [ABSTRACT FROM AUTHOR]

This paper presented the out-of-plane elastic buckling behavior of circular steel arches discretely and laterally braced, and based on FE analysis a threshold value of bracing stiffness for design was proposed. The effects of bracing parameters, including bracing stiffness, brace types, the number and longitudinal location of bracing point, on the arch elastic buckling behavior were investigated carefully. An equation for predicting the threshold value of bracing stiffness was obtained for equally-spaced lateral braces of pin-ended and fixed arches with I-section in pure compression. And the required arch segment length between bracing points to prevent the arch segment from elastic out-of-plane buckling was proposed. It shows that, the closer brace is to the crown of arch, the higher efficiency brance has to prevent out-of-plane buckling of arch. When arches with lateral braces buckle, buckling half-waves increase with the augment of bracing stiffness, while arches with torsional braces always buckle with one half-wave. For equally-spaced lateral braces, a threshold value of stiffness of arches in uniform compression is suitable to the arches under other general load conditions. When segment length meets the requirement mentioned above for arches with I-section, in-plane asymmetric buckling form will take place before out-of-plane buckling of arch segment. [ABSTRACT FROM AUTHOR]

Based on the previous studies on out-of-plane stability of arches in uniform compression and bending moment, this paper presented the research results of the out-of-plane ultimate strength of circular steel arches under the combination of axial compression and bending by using FE analysis in elasto-plastic range of materials. With the consideration of different geometric parameters, support conditions, section forms and load combinations etc, a design method for predicting the out-of-plane ultimate strength of circular steel arches was proposed based on FEA results. The results obtained indicate that the N-M interaction equation proposed for predicting the out-of-plane strength of arches is applicable for various support conditions and complex load combination, where average axial force, maximum bending moments within 1/3 arc length of arch top and stability coefficient for non-uniform moment distribution are introduced. [ABSTRACT FROM AUTHOR]

In order to create a systematic design method for out of-plane stability of steel arch under the combination of uniform compression and bending, the out-of-plane ultimate strength of circular arch under bending moment is required to be investigated at first. By considering the factors such as arch section types, initial geometric inperfection, residual stresses, rise-to-span ratio, support conditions and end moment ratio, this paper presented design principles for out-of-plane strength of circular arches under bending moment. Firstly, arches under uniform positive bending were studied and stability design curves with normalized arch slenderness for welded I-section, welded box section and hot-rolled pipe section were proposed. Then for arches under non-uniform bending with end moment, two methods of modified normalized slenderness and moment modified coefficient for calculation of the out-of-plane ultimate strength were established, which can be applied in the formulation of design method for arches under the combination of compression and bending. It shows that the stability curve of circular arches under uniform positive bending is similar to that of straight beams. Modified normalized slenderness or moment modified coefficient should be introduced to take account of the effects of moment gradient and negative moment. The results of ultimate strength calculated by the two methods proposed are close to those of FEA. [ABSTRACT FROM AUTHOR]

By considering the factors such as arch section types, initial geometric crookedness, residual stresses, riseto- span ratio and support conditions, this paper presented the out-of-plane stability design curves for circular arches under uniform compression. It can be not only applied in the practical design of arch under uniform compression directly, but also involved in the design of arch under the combination of uniform compression and bending. It indicates that load with constant direction which causes lower out-of-plane load-carrying capacity of arches is more adverse than one with direction pointing to a constant center. Compared with initial geometric crookedness and residual stresses, rise-to-span ratio and support conditions much more affect the out-of-plane load-carrying capacity. However, stability design curves for arches with different rise-to-span ratio and support conditions are unified by using the normalized arch slenderness. Finally, out-of-plane stability design method of arches with hot-rolled pipe section, welded box section and welded I section is proposed by employing stability design curves for columns of type b, c, d in Chinese code (GB 50017-2003) respectively. [ABSTRACT FROM AUTHOR]