A preventive strengthening strategy for aged steel columns

Steel columns are widely used in buildings, bridge piers, and railway platform roofs etc. With aging, those steel columns are vulnerable to corrosion and fatigue, and can deteriorate for a variety of reasons, especially in great earthquakes. In order to avoid the unrecoverable damage of existing steel columns, the high cost of the structure owners and the great impact on the public use, effective preventive maintenance methods on the aged steel piers are necessary. On this background, a strengthening method for aged steel columns by using new construction materials such as glass fiber reinforced polymer (GFRP) plates, rapid hardening concrete, rubber-latex mortar, and reinforcing bars, is introduced in this study. Depending on possible applied load directions and corrosion conditions, two specimens were used in the loading tests. Static loading tests were performed on steel columns with and without strengthening. Applied load and deflection relationship and strain distribution on original and strengthened columns were measured and compared. Moreover, three-dimensional FE models were built, and the numerical results were compared with the test results. Both experimental and numerical results indicate that the present strengthening method can significantly enhance both rigidity and ultimate load carrying capacity of aged steel columns.