Localized edge loading or patch loading of bridge girders, is frequently encountered in practice. The behavior of girders under patch loading represents complex stability and elastoplastic problems. In situation where the location of the patch load is fixed, transverse web stiffeners can be used to provide increased resistance, but for economic reasons should be avoided wherever possible. For moving load in some structures such as bridges, it is not possible to provide transverse stiffeners at all critical locations. One option is to use longitudinal stiffeners in these situations. In this article, ANSYS finite element software was used for structural analysis to investigate the ultimate resistance of plate girders subjected to patch loading. The finite element model was validated with experimental results taken from literature and found to be more accurate. Extensive parametric study was also performed to investigate the ultimate resistance of longitudinally stiffened plate girders. Furthermore, the ultimate resistance and the optimum position of the longitudinal stiffeners were presented in closed-form which showed satisfactory correlation with the theoretical results.

In this paper, the semi continuum method is developed for analysis of skew bridges with arbitrary number of longitudinal girders. In this study, two assumptions are considered and in the second assumption, a larger region of the deck contributes in load distribution. Therefore, the load distribution becomes more smooth. Results are compared with the grillage analysis method. The grillage method is considered as an accurate method in OHBDC Code. This comparison shows that the error of the first assumption is 37% with respect to grillage method and for second assumption, it is 4%.

Simply supported bridges consisting of five I-section concrete girders are analyzed using the finite element method. The main parameters of this study are: girder spacing (1.8 to 2.7 meters), span length (25 to 35 meters), skew angle (0° to 60°) and different arrangements of internal transverse diaphragms. In this analysis, 3-dimensional decks are modeled for considering interaction between the structural elements of the decks, and consequently the distribution factor of design moment for various arrangements of internal diaphragms are obtained. The results are compared and the advantages of each arrangement with respect to the others are derived. Results of reliable analysis based on the finite element method show that in right bridges, AASHTO distribution factors are conservative and in skew bridges, these factors are very conservative, such that, in skew bridges with internal diaphragms perpendicular to longitudinal girders, distribution factors of external and internal girders are 37% and 45% less than their equivalents in AASHTO, respectively. At the end, the simple relations are proposed to determine design moment distribution factors of both external and internal girders for the decks with internal diaphragms perpendicular to longitudinal girders.

Corrosion is a major challenge for the performance and health of structures. Structures in offshore, industrial, and urban settings corrode due to humidity, pollutants and various chemical agents, leading to performance reduction. plate girders have been increasingly used, and the web corrosion of such girders reduces their shear strength. This study evaluated the shear strengthening of corroded plate girders using different stiffener patterns. Corroded and non-corroded plate girders were nonlinearly analysed in ABAQUS. corrosion was modeled through thickness reduction in the numerical models. Uniform, pitting, and groove corrosion patterns as large as 25-75% of the web thickness were considered. Stiffeners were employed to strengthen the corroded plate girders. The effects of different stiffener parameters, including shape, size, and spacing, were investigated. It was found that a 50% web thickness reduction due to corrosion could decrease the shear strength of the plate girder by 47%. Pitting corrosion in the top and bottom of the web led to a 36% shear strength decline, and the top corrosion was more critical than the bottom corrosion. Flange-web disjoining due to groove corrosion diminished shear strength by 55%. Vertical stiffeners enhanced the strength of the plate girder by 54%. The results showed that T-and L-shaped stiffeners outperformed rectangular stiffeners under the same conditions.

The plate girders used in bridges usually have a deep and relatively thin web, therefore, the buckling of the web is one of the important factors in the design of such girders. While the limit state of web buckling dominant design, Longitudinal and transverse stiffeners are used to increase cross-sectional strength. The location of stiffeners in flat girders has been extensively studied, which has led to the most effective placement for longitudinal and transverse stiffeners. In the case of curved beams in the plan is not as extensive as in the case of flat girders, especially in the case of longitudinal stiffeners in the asymmetric section. Summarized herein is a study that explored single span, horizontally curved, plate girders having a yield stress of 50 ksi (345 MPa) to investigate their flexural behavior as a function of the position of a single longitudinal stiffener at various locations along the depth of the web. The studies were conducted using ABAQUS with the girder cross-sections under high vertical bending moment and low shear. As a result of these studies, recommendations are made for positioning longitudinal stiffeners on horizontally curved:-Placement of longitudinal stiffener at distances D/4, D/5, D/6 from the compression flange can control the flexural buckling of the web.-Among the above-mentioned locations, the location of the longitudinal stiffener at a distance of D/4 from the compression flange has the best shear response in the beam. Therefore, in this study, the optimal location of the longitudinal stiffener at a distance of D/4 from the compression flange.

1. Introduction: In the Civil Engineering field, we have to search a structure with lower weight and cost, to reach minimal energy and materials. Since using of Cellular and Castellated Beams can provide higher bending strength and stiffness without increasing the weight of the structure, therefore, in the recent years, they have lionized by most researchers. In some structures like bridges, in order to large stiffness and high strength, we have to use special beams with large dimensions and height. On the other hand, to solve this necessity, it is not possible to use hot-rolled Castellated Beams. So Castellated plate girders can be used. In this paper, it is denoted that castellated plate girders can be used in long spans as a convenient choice...

Long span beams with heavy load require increasing the thickness of web and in many cases using a number of stiffeners needs to improve the lateral buckling difficulty. Development and application of corrugated steel web provides facilities to modify the web thickness of beam girders in the design and construction procedure. The attractiveness for using corrugated webs in bridges and composite sections has been increased in recent years. The new system combines the usage of either corrugated steel plates as webs or steel or reinforced/ prestressed concrete slabs as flanges.The application of corrugated steel web may reduce the thickness of webs and restricts it between 2 to 5mm while increases the portion of height/thickness of corrugated web girders in industrial structures up and about 260 and even for long span bridges up to 400.Manufacturers have produced different corrugated profiles such as sinusoid, trapezoid and other forms. The investigations show that the most significant weakness of application of the corrugated web beams is failure due to shear stress. The flanges are assumed to provide the flexural strength of the girder with no contribution from the corrugated web, which is assumed to provide the entire shear capacity of the girder. The corrugated web is thus, subjected to an “almost” pure shear stress state. Failure of a corrugated steel web plate may occur by the classical steel yielding of the web under a pure shear stress state. It may also occur by web buckling due to either local instability of any “panel” between two folds or overall instability of the web over two or more panels. An interactive failure mode between these different failure criteria represents another possibility of failure and so many researchers have considered global, local and semi global buckling in phenomena due to shear strength in their research work.In this paper nonlinear 3D Finite Element Model with regarding buckling modes phenomena for shear analysis of different profile shape of available manufacture corrugated webs is intended.  The model is verified with published experimental results and sensitivity of the involved parameters is investigated. As presented in the following figure, the post-buckling strength of girders with corrugated steel webs could be investigated by this model.The geometric parameters that influence the shear resistance of trapezoidal corrugated web girders investigated in this study, involve:1) Corrugation angle 2) Width of the plane sub panel of the web 3) Web thickness 4) Height of the web 5) Corrugation depth of the web. The parameter study is developed for the sine corrugated web by focusing on amplitude of the central curve of the web and the wave length of the central curve of the web. Corrugated web shear capacity is changed by altering of the amplitude and wave length of the sinusoidal corrugated web. These changing manners are presented in the following figures respectively:Results show, the sinusoidal webs have better performance than trapezoidal webs in the same conditions. The optimum size of trapezoid and sinusoid dimensions depends to the thickness of applied plate for producing the profile. Concerning to the manufacture restriction for production of profile, the study shows that the maximum shear strength will appear in the sinusoid profile for amplitude of 3 to 4 centimeter while in the trapezoid profile the equal dimension for flat and inclined part in the profile provides maximum shear strength.

The use of plate girders with corrugated sine wave web have been vastly increased due to more buckling strength and out of plane stiffness. Composite girders with corrugated web and pre-stress concrete flange have been recently used in bridges. Trapezoidal, zigzag and sine shapes are the plate forms that are used in this type of girders. In this paper a three dimensional finite element model with special concentration on buckling modes is considered to carry out analysis of girder and obtain shear stress having sine form corrugated plates. The results obtained from nonlinear analysis showed that the orthotropic behavior of web for global buckling is a true assumption. The available equation for global buckling of flat plates has been modified by defining an effective width for buckling of sine waves which is obtained by introducing a factor in linear distance between maximum and minimum points of wave, depending upon geometrical dimensions of sine waves. For a typical wave length, optimum amplitude of sine wave can also be determined from this analysis for maximum shear strength of the web.

Web of plate girders in bridges are usually reinforced by welded transverse stiffeners in order to improve their shear capacity. Due to problems associated with field welding and fatigue, welded stiffeners are not suitable for retrofitting existing bridges. Bolted stiffeners are a practical alternative for strengthening girders that are expected to experience shear stresses in excess of their design shear capacity. This paper presents the results of an analytical study into behavior of plate girders with bolted transverse stiffeners. Based on this study new requirements are developed for design of such girders.

The web of plate girders in bridges are usually reinforced by welded transverse stiffeners in order to improve their shear capacity. Due to problems associated with field welding and fatigue, welded stiffeners are not suitable for retrofitting existing bridges. Bolted stiffeners are a practical alternative for strengthening girders that are expected to experience shear stress in excess of their design shear capacity. This paper presents the results of an analytical study into behavior of plate girders with bolted transverse stiffeners. Based on this study new requirements are developed for designing of such girders.