A new design method for prestressed concrete girder is proposed in this study, which steps for manufacturing are ; (1) the bottom part of concrete girder is placed and pretensioned by the first post-tensioning performed on the tendons located in the bottom part of concrete girder, and (2) the next step which consists of concrete placing and post-tensioning operation is followed by the previous step if required. This process allows efficiency of girder section to be enhanced, resulting in reduction of demanded height with the same span length, or in increase of the span length with the same height of the girder section. This indicates that sufficient compressive stress can be effectively introduced at the bottom face in stepwise manner, when compared to conventional PSC girder.
Two specimens are prepared and tested to investigate the short-term behavior of the PSC girders manufactured by the proposed method. Section Analysis results exhibit good agreements with the test results in terms of strain distribution across the girder section. In addition, flexural strength obtained from the ests is found to be similar to the expected based on ACI code. These demonstrate that the method proposed in this study is applicable to the design of PSC girders.
