Analysis & Design of Prestressed Concrete Bridge

Abstract

Prestressed concrete is a technique that greatly increases load bearing strength of concrete sections. A fully prestressed concrete member is usually subjected to compression during service life. This rectifies several deficiencies of concrete. High span to depth ratio is possible due to prestressing. This decreases the size of the members which makes the project more economical.

No significant work has been conducted to identify the influence of intermediate diaphragms on load distributions and effects of skew angle on design parameters. Especially there are no guidelines provided by IRC on providing of intermediate diaphragms. We can observe most of bridges with I and T sections have no diaphragm. This study aims to quantify the intermediate diaphragm influence on load distributions. The presented information will help examine the functions of intermediate diaphragms and develop policies of intermediate diaphragm practice for prestressed concrete bridges.

In this study the effect of intermediate diaphragms on distribution of vehicular loads to each of the longitudinal beams are investigated. The bridge was tested first with the different thicknesses and then with intermediate diaphragms placed at suitable locations. It was found that the intermediate diaphragms transmit load laterally very efficiently. The maximum bending moment and deflections in girders transmitted directly under the vehicular loads were slightly reduced by the use of the diaphragms, when the bridge was loaded with IRC loading. Also the effect of skew angle was studied by comparing with the test results with non skew bridges of similar dimensions