Residual shear strength of steel plate girder due to web local corrosion Jin-Hee Ahn a , In-Tae Kim b, ⁎, Shigenobu Kainuma a , Myoung-Jin Lee b a Department of Civil Engineering, Kyushu University, Fukuoka 819-0395, Japan b Department of Civil Engineering, Pusan National University, Busan 609-735, Republic of Korea abstract article info Article history: Received 21 November 2012 Accepted 1 July 2013 Available online 2 August 2013 Keywords: Web local corrosion Shear failure Post-buckling Strength reduction factor Plate girder Corrosion damage around the supports of steel plate bridges due to high humidity and depositions as well as rainwater and antifreeze penetration into drainage type expansion joints have been frequently reported. However, the residual shear buckling strengths and behaviors have not been sufficiently evaluated and its evaluation method has not been clearly established. Therefore, in this study, the shear buckling failure modes of web panels with local corrosion were numerically examined from their post-buckling behaviors as well as their shear buckling behaviors. Their shear buckling values were quantitatively evaluated from nonlinear FE analyses model by varying the corrosion conditions and geometrical conditions of web panels. In addition, the FE analysis results were compared with values calculated by a theoretical equation and de- sign specifications. A residual shear strength reduction factor that could be used to estimate the residual shear strength of the plate girder with local corrosion was presented from the relationships between the re- sidual shear strength and the corroded web volume. © 2013 Elsevier Ltd. All rights reserved. 1. Introduction In Japan, there is a growing interest in the improvement of the durability, the evaluation method of the residual strength, and the maintenance of steel bridges with service periods of more than 50–70 years [1]. Corrosion maintenance is becoming an important issue because various cases of severe corrosion and fatigue problems have been reported. For example, Fig. 1 shows a plate girder bridge that collapsed in 2009 owing to severe corrosion after about 28 years of usage, Fig. 2 shows a steel truss girder bridge that col- lapsed in 2007 owing to severe corrosion after about 57 years of usage, and other corrosion failures of bridge members have also been reported. These failure cases highlight the need for assessment tech- niques for corroded structures and their structural residual strength, and adequate maintenance to prevent corrosion damages. Therefore, various studies on corroded steel and members have been conducted and repair methods for corroded members have been proposed [2–11]. However, the behaviors and strengths of the corroded members were limited because the corrosion shape and form are not environ- mentally uniform and are affected by several corrosion factors such as temperature, relative humidity, airborne chloride ions, and time of wet- ness [2–11]. In the case of steel plate girder bridges, corrosion damage easily occurs at the support as shown in Fig. 3. This corrosion damage occurs because of poor air circulation that causes high humidity, sediment and depositions, and rain water and antifreeze penetration from drain- age type expansion joints. This corrosion can affect the shear strength of the web and change its shear behaviors. However, evaluating the resid- ual strengths and shear behaviors of the web under varying web thick- ness reduced by corrosion is not enough, and an evaluation method is yet to be established [2,3,7–9]. Therefore, the shear loading tests were conducted to examine the shear buckling behaviors of the web panel with the local corrosion [12]. However, it was not sufficient to evaluate the shear buckling behaviors and residual shear strength of the web panel with local corrosion according to the numbers of specimens and limited corrosion condition, and their failure modes were not clearly explained depending on various corrosion conditions. FE analyses also did not consider the change in the geometrical properties of the web panel. Therefore, in this study, the shear buckling behaviors and shear buckling failure modes of web panels with local corrosion were numer- ically examined. Their shear buckling values were quantitatively evalu- ated from nonlinear FE analysis model by varying the corrosion conditions and geometrical conditions of web panels. In addition, FE analysis results were compared with critical buckling loads and shear strengths calculated using theoretical equations and design specifica- tions. The residual shear strength reduction factor of the plate girder with local corrosion was presented to estimate its residual shear strength. 2. FE analysis model In order to examine the residual shear strength of the web panel with local corrosion, shear loading tests were conducted on plate girders under five corroded web conditions [12]. Therefore, in this Journal of Constructional Steel Research 89 (2013) 198–212 ⁎ Corresponding author. Tel.: +82 51 510 2497; fax: +82 51 510 8181. E-mail address: itkim@pusan.ac.kr (I.-T. Kim). 0143-974X/$ – see front matter © 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.jcsr.2013.07.008 Contents lists available at ScienceDirect Journal of Constructional Steel Research