Possibility of Increasing the Load Bearing Capacity of Parapet Bridge Structures

Abstract

Post-tensioning is a suitable, reliable and durable method for strengthening existing reinforced concrete bridge structures. The high efficiency of post-tensioning can be seen on many implemented applications for bridge reconstructions worldwide. There are still several thousands of beam and slab bridges the load capacity of which no longer meets the demanding transport conditions. The oldest reinforced concrete beam bridges, from 1905-1915, are designed according to the Austrian Ministry of Railways Bridge Standard of 1904 when the largest load to be considered was the 18-tonne road steamroller. These bridges are not dimensioned for the currently valid traffic load values. The paper deals with the strengthening of the parapet beam bridges from the period of 1905-1930. These bridges have two main beams pulled over the bridge deck which is supported by cross beams. The cross beams connect the two main beams, forming a half-frame in the transverse direction which provides spatial rigidity of the structure. The spans of these bridges are usually in the range of 15 to 25 m.

Strengthening and Rehabilitation of U-Shaped RC Bridges Using Substitute Cable Ducts

“…e cross girders connect both main girders, and together with them, they form a half-frame in the transverse direction; the half-frame provides spatial rigidity to the structure. ese bridges can also be efficiently strengthened using the substitute cable duct method both in the longitudinal and transverse directions [22]. e spans of these structures are between 15 and 25 mm, and the described strengthening was used in the realized designs, e.g., [21,23].…”