装配式PC箱梁长期存梁期间上拱影响因素及控制研究

装配式预应力混凝土(PC)箱梁在桥梁工程中应用非常广泛。内蒙古地区冬季时间长,装配式PC箱梁往往需要在梁场长期存放,而箱梁长期存放可能会导致其上拱过大、桥面铺装过薄、耐久性等问题。本文分析总结了影响箱梁上拱的因素,依托实际工程,采用有限元分析方法研究了存梁时间、张拉龄期、张拉预应力、环境相对湿度、均匀压重等因素对装配式PC箱梁上拱的影响规律,并据此提出了长期存梁期间控制上拱的措施。研究结果表明:存梁时间越长,各个因素的差异对箱梁的上拱影响程度越大,这种差异造成的上拱值不可忽略,其中张拉龄期和张拉预应力对长期存梁的上拱变形影响较大,而通过均匀压重可有效控制箱梁长期存梁的上拱变形。

Research on Influencing Factors and Control for Upper Arch of Assembled PC Box Girder During Long-term Storage

Prefabricated prestressed concrete(PC) box girder is widely used in bridge engineering.In Inner Mongolia,the winter time is long.The assembled PC box girder often needs to be stored in the beam for a long time,and the long-term storage of box girders may lead to problems such as excessive arch,thin deck pavement and durability.In this paper,the factors affecting the upper arch of PC box girders were analyzed and summarized.Based on practical engineering,the influence rules of girder storage time,tension age,tension prestress,environmental relative humidity and uniform pressure on the upper arch of PC box girders were studied by finite element analysis method,and the measures for controlling the upper arch of PC box girders during long-term storage were put forward accordingly.The results show that the longer the storage time,the greater the influence of different factors on the upper arch of box girders.The value of the upper arch caused by this difference can not be neglected.Tension age and prestressing force have great influence on the upper arch value of long-term storage girders,and uniform weight can effectively control the upper arch of box girders during storage period.