Because of its large volume,the 0# block of long span PC continuous rigid frame bridge can be clearly affected by the temperature stress which is produced by the hydration heat of concrete.Therefore the hydration heat of concrete is the main factor of early cracking of 0# block,which will influence the safety and durability of bridge.Relying on Hong Yan Xi Bridge,transient thermal analysis method of ANSYS software was used to calculate the temperature field of hydration heat in 0# block under the influence of external temperature.When compared,the calculated results can match well with the measured data.The stress field can be calculated when applying the temperature field to the structure.The results show that the thicker the plate of each position in 0# block is,the higher the temperature in center is,and the longer the time of maximum value is.Maximum principal tensile stress produced by the hydration heat is between 3.20~ 4.59 MPa and the value exceed the design tensile strength of concrete.As a result,the method that applying a new silicon polypropylene fiber concrete material to 0# block of long span PC continuous rigid frame bridge is proposed in the paper,in order to greatly improve the anti-cracking capability of structure because of its good early tensile strength.%大跨PC连续刚构桥的0#块可视为大体积混凝土,因此水泥水化热所产生的热量会使结构升温,导致刚构桥0#块早期可能会生成温度裂缝,从而影响桥梁整体的安全性及耐久性.依托红岩溪特大桥,采用ANSYS软件瞬态热分析法计算在外界温度影响下0#块水化热温度场,并将结果与实测数据作比较,吻合度较好,将温度场施加至结构中,计算出应力场.由结果可知:0#块各位置板厚度越大,中心位置温度峰值越大,达到最大值时间越长.水化热产生的最大主拉应力在3.20~4.59 MPa之间,超过了混凝土设计抗拉强度,因此文中提出在大跨PC连续刚构桥0#块中采用新型硅粉聚丙烯纤维混凝土材料,以其良好的早期抗拉强度,能够较大的改善结构的抗裂性能.
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