Journal of Constructional Steel Research 67 (2011) 647–655 Contents lists available at ScienceDirect Journal of Constructional Steel Research journal homepage: www.elsevier.com/locate/jcsr Fatigue analysis of a pre-fabricated orthotropic steel deck for light-weight vehicles Huu-Thanh Nguyen a , Quoc-Thang Chu b , Seung-Eock Kim a,∗ a Department of Civil and Environmental Engineering, Sejong University, 98 Kunja-dong, Kwangjin-ku, Seoul 143-747, South Korea b Viet Nam National University — Ho Chi Minh City International University, Viet Nam article info Article history: Received 19 December 2009 Accepted 16 November 2010 Keywords: Orthotropic steel deck Fatigue Light-weight vehicle Fracture mechanics Life prediction abstract An orthotropic steel deck designed for carrying light-weight vehicles was investigated to assess its fatigue life. Fracture mechanics analysis was performed with consideration of pre-existing flaws at the fatigue- sensitive region. Three-level models were used to accurately evaluate the stress-intensity factors at the rib-to-diaphragm connection. The crack growth was simulated by numerical integration of the Paris formula. In order to assess the severity of pre-existing flaws at the welded joint of the rib-to-diaphragm connection, the fatigue life of the deck was investigated with different sizes of initial crack. This approach provides a rational quality assessment method for the orthotropic steel deck. © 2010 Elsevier Ltd. All rights reserved. 1. Introduction In recent years, traffic congestion has become more serious in the big cities in Korea. One reason for the congestion is the in- creasing number of passenger cars while existing roads are limited. Constructing roads for only passenger cars can be an efficient alter- native in both construction time and cost aspects. The elevated- bridge road system for only light-weight vehicles that uses a pre-fabricated orthotropic steel deck proves to have many bene- fits. The major benefits of this system are its light weight since it is designed only for passenger cars; and short erection time by us- ing welding-free construction on-site. This road system for light- weight vehicles enables cutting of construction costs and time by 50% as presented by researchers at the Korea Society of Civil Engi- neers (KSCE) conference [1]. It is known that the orthotropic steel deck is liable to fa- tigue cracking once placed in service. Several studies using exper- iments [2–5] and analysis [6–10] were carried out to investigate the fatigue of orthotropic steel decks subjected to heavy vehicle loads, while a limited number of studies [11,12] for light-weight vehicle loads were performed. The fatigue of orthotropic steel decks carrying only light-weight vehicles has not been studied. In this paper, the fatigue behavior of a pre-fabricated orthotropic steel deck which is one of the deck types considered for the elevated road system is presented. ∗ Corresponding author. Tel.: +82 2 3408 3291; fax: +82 2 3408 3332. E-mail address: sekim@sejong.ac.kr (S.-E. Kim). The S –N curve method has been widely used for the fatigue design of bridges. S –N curves, however, are only available for a limited number of structural details, given by classification tables of design codes such as AASHTO [13] or KSCE [14]. Recently, the fracture mechanics methodology has become more widely accepted. The fracture mechanics design methodology emerged from the automotive and aerospace industry. It deals with crack growth and the residual strength of cracked structures. One crucial piece of information is the crack propagation curve showing how a crack grows by fatigue. Crack growth curves can be obtained numerically or experimentally. The fracture mechanics approach offers many distinct advantages in that (i) it is reliable, (ii) it enables a quantitative evaluation of the damaging effect of flaws or defects in the material, and (iii) it provides a rational basis for quality control of the product. In this work, an orthotropic steel deck is investigated using fracture mechanics analysis to predict its fatigue strength under light-weight vehicle loading. In the analysis, the three-level mod- eling technique is used to precisely obtain the stress-intensity fac- tors for different crack sizes. The stress-intensity factors associated with self-weight load and vehicle load are computed. Then they are used to simulate the crack growth and to estimate the fatigue life of the deck. An initial flaw is assumed in the deck and its growth is simulated by numerically integrating the empirical Paris formula. The fatigue life of the deck with the initial flaw size is then esti- mated. Fatigue experiments are performed to investigate the fatigue strength of the deck and to obtain specific test values to aid the crack growth simulation. Three full-scale specimens of the or- thotropic deck module are tested with three different load ranges, 0143-974X/$ – see front matter © 2010 Elsevier Ltd. All rights reserved. doi:10.1016/j.jcsr.2010.11.015