预应力混凝土箱梁桥腹板施工裂缝成因与对策

为了找出预应力混凝土连续箱梁桥施工过程中，腹板有可能出现斜向裂缝的原因，运用光纤技术对预应力张拉过程进行监测，并利用有限元软件ANSYS对结构进行模拟分析。结果表明：有斜向预应力钢束区域大部分范围内的第一主应力均大于2.60MPa，得知裂缝是腹板内主拉应力超过混凝土抗拉强度所致，受腹板纵向预应力布置方式的影响。

Cause and countermeasure of slab cracks of pre-stressed concrete continuous box girder

In order to find out the causes of cracks appearing in slab of the girder during the construction of prestressed concrete continuous box girder, monitoring technology with optical fiber was used for the monitoring of the course of prestressing, and the finite software ANSYS was adopted to simulate and calculate the structure. Results show that the first principal stress in most area of the slab is over 2.60 MPa, so the cause of cracks is that the main tensile stress in slab exceeds the standard value of tensile strength of concrete, which is affected by the layout of lengthways prestress steels in slab.