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In this paper, a realistic nonlinear 3D simulation of an incrementally launched steel bridge girder is presented. The numerical simulation accounts for three sources of nonlinearity: geometry, material and boundary conditions. For the sake of depicting the capabilities of the presented numerical model in structural verifications, the study is focused on the patch loading field, a structurally complex phenomenon. Patch loading (or concentrated loading) is one of the most typically encountered structural verifications on incrementally launched steel I-girders. The presented realistic simulation is based upon an experimentally calibrated numerical model and may provide relevant information at both design and construction stages. For the former, the predictive capabilities of the model for inferring the potential failure due to patch loading are depicted. For the latter, the results obtained are displayed in a way that may be useful for planning a Structural Health Monitoring (SHM) deployment aimed at controlling the patch loading-related phenomena in incrementally launched steel plate girders. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, a mechanical model aimed at predicting the ultimate load capacity of transversally stiffened steel plate girders subjected to patch loading is revisited. This mechanical model gives accurate results for homogeneous steel plate girders (identical yield strength for web and flanges) but it is found that for the case of hybrid girders (fyf/fyw), certain correction factors must be added for maintaining the same level of accuracy. The provided correction is inferred empirically from a series of experimentally calibrated numerical results and the resulting formulae are expressed in accordance with the EN1993-1-5 procedure. [Copyright &y& Elsevier]

Abstract: In this paper, a mechanism solution aimed at reproducing the ultimate load capacity of steel plate girders subjected to patch loading is provided. This mechanism is particularly useful for the cases in which the steel plate girders present closely spaced transverse stiffeners. A thorough description of the influence of the transverse stiffening on the ultimate load capacity of girders subjected to patch loading is given partly herein and in a companion paper. Presently, the formulation provided in EN1993-1-5 underestimates the ultimate load capacity of girders presenting such geometrical proportion. Comparisons between numerical and theoretical results show the accuracy of the proposed model. The results obtained with such prediction prove structurally sound and enhance satisfactorily the current formulation of EN1993-1-5. [Copyright &y& Elsevier]

Abstract: In this paper, an experimental programme of six steel plate girders subjected to patch loading as well as results of forty eight numerically-tested prototypes are presented. Results of ultimate load capacity as well as structural responses from these girders are provided. In addition, experimental and numerical values of ultimate load capacity are compared with those predicted by EN1993-1–5. With such results, the response of transversally stiffened steel plate girders is discussed throughout the paper. Particular emphasis is given to the influence of the transverse stiffening on the ultimate load capacity of the girders. It is observed that girders with largely spaced transverse stiffeners present a considerably different response from girders with closely spaced transverse stiffeners. The structural response for the former case has been thoroughly studied in the last decades whereas little attention has been paid for the latter. Further analysis of this particular topic is provided in a companion paper. [Copyright &y& Elsevier]

Abstract: This paper presents an assessment of the influence of structural imperfections, namely, the residual stresses, on the ultimate load capacity of steel plate girders when subjected to patch loading. The basis of the research is a thorough comparison between numerical and experimental results as well as the recommendations for FE-modeling suggested by EN1993-1-5 (Annex C). A systematic exploit of a properly validated numerical model has been used in this study. Several residual stress patterns found in the literature have been implemented in numerical simulations of four different tests on girders subjected to patch loading. On such a basis, an appraisal of the influence of the structural imperfections on the ultimate load capacity of girders subjected to patch loading is presented. [Copyright &y& Elsevier]

Abstract: Hybrid girders subjected to patch loading have been analyzed in a detailed fashion for the case in which the plates that assemble the girders are transversally stiffened. Scant work, however, is available for the case in which the girders are hybrid and, simultaneously, longitudinally stiffened. The driving force for developing the present research work is to complete the knowledge of the patch loading field for the particular structural alternative of a hybrid steel plate girder assembled with a longitudinal stiffener. In the current paper, a numerical database of 255 simulations on longitudinally stiffened steel girders subjected to patch loading developed by the authors is presented. The results obtained are used for assessing the resistance of longitudinally stiffened hybrid steel plate girders subjected to patch loading. Some discrepancies between the numerical and EN1993-1-5 results are pinpointed. A design proposal which enhances the current EN1993-1-5 formulation is given at the end of the paper. [Copyright &y& Elsevier]

Abstract: The resistance of plate girders subjected to patch loading has been studied thoroughly for the case of homogenous girders. The particular case of hybrid girders has been generally treated identically than for homogenous specimens. In this paper, the current EN1993-1-5 formulation is evaluated and some peculiarities concerning the treatment of hybrid girders subjected to patch loading are pinpointed. It is numerically demonstrated that the moment capacity of the flanges does not play any role in the resistance of plate girders to patch loading as predicted in EN1993-1-5. Accordingly, a design proposal which corrects the current EN1993-1-5 formulation is presented at the end of the paper. [Copyright &y& Elsevier]

Abstract: Extensive research focused on the structural behavior of hybrid steel plate girders is nowadays available in the literature. Furthermore, extensive research devoted to the resistance of homogeneous girders to patch loading has been performed in the last decades. Investigations dealing simultaneously with both fields are, however, rather scarce. The driving force behind developing the present research work has been the aim of completing the knowledge of the patch loading field for the particular structural alternative of hybrid steel plate girder. In the current paper, experimental results found in the literature as well as additional numerical simulations developed by the authors are summarized. The results presented can be used for assessing the resistance of hybrid steel plate girders subjected to patch loading. An in-depth exploit of such results is presented in a companion paper. [Copyright &y& Elsevier]

Abstract: European design rules EN1993-1-5 allows the usage of FE-Analyses as reliable tools in the verification of limit states of plated structures. Throughout the modelling of these structures, certain initial conditions must be assumed. Consequently, engineering judgment is needed to some degree. This paper presents an assessment of the influence of these conditions on the ultimate load capacity of steel plate girders when subjected to patch loading. The basis of the research is a thorough comparison between theory and design rules by means of experimental and numerical results. The results obtained prove usefulness for practical and academic purposes alike. [Copyright &y& Elsevier]