Research On The Shear Capacity In Prestressed Concrete Bridge

Prestressed concrete bridge with its clear carrying capability and fine economic properties, has been widely developed. During the prestressed concrete bridge operation, prestressed concrete bridge appear the box girder crack and inclined section of shear capacity and exist many factors related to the problem. The article direct at the prestressed concrete bridge shear bearing capacity theoretical research, explore the influence pattern,the main research work include:1) Contrast the China highway bridge standard(JTG D62-2004),American concrete standard (ACI318-08), Germany standard (DN - 1045),Europe standard (Euro Code 2-1992) and USSR concrete Code (1984) about the inclined section of the article provision of shear capacity. Based on the typical examples, JTG D62-2004 in shear capacity for inclined section empirical formula is divided into concrete and stirrup, prestressed,vertical prestress, vertical prestress Provided the shear capacity is bigger is bigger than the ACI318-08, shear capacity of the stirrups and section on the shear capacity is bigger than the JTG D62-2004.overall D62-2004 JTG calculation of shear capacity for inclined section slightly greater than ACI318-08.2) Using JTG D62 2004 and American concrete standard ACI318-08 on the diagonal crack of shear capacity empirical formula. Though six typical prestressed concrete continuous bridge on the shear capacity calculation. In the shear capacity calculation value composition, concrete girders webs provide in the shear capacity of shear capacity for inclined section calculated 50% ~ 70%;Stirrup inclined section in part of shear capacity calculation value of 8% to 16%;In vertical prestress part of shear capacity for inclined section in the calculated 40% ~ 50%;Prestressed part inclined section of shear capacity calculated 0.6% ~ 5% .3) The influence factors (webs width, stirrup reinforcement ratio, vertical prestress spacing and effective prestressed size, prestressed size) for the PC box girder of shear capacity inclined cracks the parameter sensitivity analysis, vertical prestress inclined section of shear capacity of the most sensitive, concrete webs, prestressed reinforced the width times of shear capacity for inclined section the sensitive. In prestressed concrete box girder bridge design process, strength the vertical prestressed reinforced shear design.4) Based on the general finite element software ANSYS, considering material nonlinearity and the geometrical nonlinearity, established the PC continuous box girder bridge spatial finite element, selecting solid65 unit, link8 unit as prestressed; Concrete adopts Miso concrete constitutive relationship; Yield criterion employ Wlilam - Warnker five parameters failure criteria.5) Through the prestressed concrete box bridge on the L / 4 position in the maximal tensile stress ultimate bearing capacity, research in the different load factor,roof and floor, and webs of the box bridge's tensile stress variation regular pattern, and the trend development. of the concrete inclined cracks.6) Based on PC continuous box-girder bridge spatial finite element model, by changing the webs width, prestressed size, vertical prestress size of related parameters, study the influence law of the prestressed concrete box bridge's ultimate bearing capacity.