Numerical study on remaining strength prediction of corroded Steel bridge plates

Corrosion causes strength deterioration of aged steel infrastructures and hence careful evaluation of their remaining load-carrying capacities are of high importance in maintenance engineering. To develop a more reliable strength estimation technique, only experimental approach is not enough as actual corroded surfaces are different from each other. However in modern practices, numerical simulation is being used to replace the time-consuming and expensive experimental work and to comprehend on the lack of knowledge of mechanical behavior, stress distribution, ultimate behavior and so on. Therefore, using of numerical analysis method will give important knowledge not only for strength estimation but also for subsequent repair and retrofitting plan. The results of non-linear FEM analysis of many actual corroded plates with different corrosion conditions and comparison of them with the respective tensile coupon tests results are presented in this paper. Further, the feasibility of establishing of an analytical methodology to predict the residual strength capacities of a corroded steel member with fewer number of measuring points are also discussed

Investigation on Residual Cyclic Strength Capacity of Corroded Steel Bridge Members

Steel bridges play a major role in road and railway infrastructures hence it directly influence on economy of any country. Traffic capacity reduction or even a temporary closure generates major inconveniences for the users and result in significant losses to the economy. Corrosion is one of the most significant causes of age related deterioration of steel girder bridges which affects their strength, long term mechanical performance, usability and durability. Numerous steel bridge structure collapses are associated with dynamic loadings like earthquakes and wind loading. Damaging vulnerability of steel structures due to dynamic excitations can be triggered with corrosion. Non availability of information and convenient methodology to determine the behavior of corroded steel members can lead to problematic situations for the civil engineers when evaluating the strength of deteriorated member. Therefore a comprehensive study in front of serviceability and ultimate limit states is necessary to develop efficient techniques to evaluate the structural integrity and safety. This is necessary to evaluate the feasibility of those steel structures for the current usage and to figure out the retrofitting requirement of corroded members. This research proposes a simple and reliable methodology to estimate remaining yield and ultimate cyclic strength capacities by measuring only the minimum thickness of a corroded surface based on the results of many experimental coupon tests and results of nonlinear FEM analysis of many actual corroded plates with different corrosion conditions, which can be used to make rational decisions about the maintenance management plan of steel infrastructures

Enhanced effective thickness for remaining strength estimation of corroded steel bridge members

Infrastructure plays a major role in the economy of a country. Bridges are a major component of any infrastructure and the failure of a bridge will affect the economy of any country. Over the past decades there have been many damage examples of older steel bridge structures due to corrosion around the world. Exposure of a steel structure to the natural environment and inadequate maintenance will cause corrosion and leads to impairment of its operation. Efficient maintenance, repair and rehabilitation of existing bridges require the development of a methodology that allows for an accurate evaluation of load carrying capacity and prediction of remaining life. Therefore, careful evaluation of remaining load-carrying capacities of corroded steel bridge structures is of high importance in transportation and maintenance engineering. Even though there are some published methods to assess the strength reduction due to corrosion of bridges, all of them were developed by using specimens with about 30mm width. However during the preliminary investigation, it was found that many corrosion pits with more than 30mm diameters exist in actual severe corroded members. So, the influence of such corroded conditions could have been neglected and hence their actual remaining strengths might be different than those were obtained from those experimental studies. Therefore, this paper investigates the effect of actual corroded conditions on their remaining strength capacities and proposes a simple, efficient and accurate residual strength estimation method by using an enhanced effective thickness parameter with the correlation of maximum corroded depth, which can be used for the maintenance management of aged steel bridge infrastructures

Numerical investigation of future tsunami hazard on Sri Lanka From the earthquakes of Sumatra-Andaman region

The mega event of Indian Ocean Tsunami 26th December 2004, stressed the need for assessing tsunami hazards in vulnerable coastal areas in Sri Lanka. Two major areas of the management of disaster prevention are to evacuate people in the coastal area to safer areas as soon as possible and pre-modification of coastal structures to resist the tsunami waves effectively. Often the only way to determine the potential run-ups and inundation from a local or distant tsunami is to use numerical modeling, since data from past tsunamis is usually insufficient. It then might be possible to use such simulations to predict tsunami behavior immediately after an earthquake is detected. This paper consists of results of the numerical models of 26th December 2004 Tsunami and three other possible Tsunamis in this region which eventually can be used to create inundation and evacuation maps to minimize future damages

Evaluation of tensile strength deterioration of steel Bridge plates due to corrosion

Over the past decades there have been many damage examples of older steel bridge structures due to corrosion around the world. Even though there are some published methods to assess the strength reduction due to corrosion of bridges, it is hard to find any with lesser number of measuring variables which eventually accounts for the accuracy and the convenience of the investigation for adequate bridge management. So, in this study, a simple method of calculating the remaining yield and tensile strength by using a concept of representative effective thickness (teff) with correlation of initial thickness (t0) and standard deviation of thickness (σst) is proposed, based on the results of many tensile coupon tests of corroded plates obtained from a steel plate girder used for about 100 years with severe corrosion