刘金侠 李长荣

摘 要：预应力钢筋混凝土，就是事先人为地在钢筋混凝土中引入内部应力，且其数值和分布恰好能将使用荷载产生的应力抵消到一个合适程度的混凝土。预应力钢筋混凝土结构由于采用了高强度材料和预应力工艺，节省了材料，减少了构件截面尺寸，进而减轻了构件自重，因而特别适合于建造由恒载控制设计的大跨度桥梁。在曲线配筋或大型构件的桥梁施工中，多采用后张法建立预应力，靠锚具来传递和控制预应力。预应力钢绞线施工是桥梁施工质量控制的关键环节之一，在施工中要高度重视。本文就箱梁预应力钢绞线施工中的各施工环节质量控制进行论述。

关键词：后张法；预应力；质量控制

Quality control of post-tensioned reinforced concrete box girder

Liu Jin-xia，Li Chang-rong

Abstract： Prestressed reinforced concrete， is that the prior factitious ground is introduced in reinforced concrete inner stress and its numerical and distribution can be produced using just the stress offset load to a suitable degree of concrete. Prestressed reinforced concrete structure as a result of the high strength materials and the prestressing processes， save material， reduced the component section size and thus alleviate the components， and particularly suitable for gravity by constant load control design to build the large span bridge. The curve of large components reinforcement or the bridge construction in， use more zhang method to establish the prestressed， after by the anchorage to transmission and control of prestressed cable. Prestressed strands of the bridge construction quality control of construction is one of the key links， in construction， must pay close attention to. This paper box girder construction of prestressed strands of construction link quality control system were discussed.

Key words： This law； Prestressed； Quality control.

1.千斤顶与油表校正

预应力张拉的设备应按锚具说明书的千斤顶型号配套使用。千斤顶在使用前必须按要求及时经主管部门授权的法定计量技术机构进行千斤顶、油泵及油压表配套标定，确定其校正系数，张拉时严格按标定报告上注明的油泵号、油表号和千斤顶号配套安装使用。张拉前，应按照校正系数公式计算出分级加载的油表读数与张拉力的对应值。

在下列情况下应重新标定：新千斤顶初次使用前；油压表指针不能退回零点时；千斤顶、油压表和油管进行过更换或维修后；当千斤顶使用超过6个月或张拉超过200次以上；在使用过程中出现其他不正常现象。

由于千斤顶和仪表的特殊作用，要求千斤顶和仪表由专人使用和管理，操作人员需具备预应力施工知识方可上岗操作。……