Analysis And Experimental Study On Local Stress In Anchorage Zone Of Long Hua Bridge

In the anchorage zone of pre-stressed concrete box girder, the stress state of concrete becames more complex because of anchor or other concentrated loads, it is different from stress state that obtained by the theory of plane assumption, at the local anchorage zone, it generates transverse crushing stress near the plate and transverse pulling stress at other parts, if the anchor tonnage is fairly large, the pulling stress may achieve great value, there is probably a result of longitudinal crack, accidents caused by local pressure zone's cracks are not uncommon in engineering. For the bridges using large-tonnage special anchor, the crack resistance and safety of the anchorage zone are the key part in the process of design, but the existing codes have not given a precise and simple method of checking, so the stress status of anchor zone needs detailed calculated analysis and experimental study.A study of the stress and strain distribution of anchorage zone in a long span PC box girder was undertaken in the baekground of Songyuan Longhua Songhuajiang River Bridge.First of all, a space linear elastic finite element model to the toothed plate of box-girder web plate was set up using ANSYS software, The accuracy of the analytical results of the model and the safety of tooth plate anchorage zone had been cheeked through the comparisons to the results of the field measurement which was carried out during the tensioning process at the stage of the girder construction.Secondly, it analyzed the stress characteristics of the multi-area bearing surface on the use of special anchor component anchorage zone, and its stress state is closely related to anchor shape, each additional plate would add an additional stress concentration area.Finally, it maked a analysis of the different impact factors which impact the stress status of anchorage zones, including the impact of channels, the impact of anchor, the impact of structural steel, and the impact of section size. By changing the parameters of different factors to analyze the influence of anchorage zone stress state, the influence is mainly for longitudinal stress, horizontal stress and vertical stress of anchorage zone, it identifies one of reasonable parameters and provides the beneficial reference for the anchorage zone design.