Page 174 - Water Standards
P. 174

fication. The allowable error can be referred to in Table 2   8   11-2.
                           2  Cast⁃in⁃place concrete bents. The sequence of concrete place⁃
                       ment of bents shall be arranged well. The rising speed of concrete
                       should be controlled to be around 1   0m/ h. Before the concrete place⁃
                       ment, the formwork supports shall be strengthened to keep the
                       stability of the formwork. During the process of placement, the bent
                       shall be observed at all times. If there is any deflection, it shall be
                       adjusted right away.
                           3  Prefabrication and hoisting of bents. The hoisting and instal⁃
                       lation of bents shall meet the requirements of Section 2   9 in this spec⁃
                       ification.
                           4   The allowable errors of the cast⁃in⁃place and prefabricated
                       bent installation shall meet the requirements of Articles 2   7   22 and
                       2   9   4 in this specification.
                           5  The construction of arch structures built by masonry or con⁃
                       crete precast blocks shall meet the requirements of Article 2   8   13 in
                       this specification and other relevant requirements.
                           6  Fabricated rib arches. The prefabrication, transporting and
                       hoisting of rib arches shall meet the requirements of Sections 2   7 and
                       2   9 in this specification.
                       3   6   3  The construction of cast⁃in⁃place concrete aqueduct bodies
                       shall meet the following requirements:
                           1  The formwork supports of the cast⁃in⁃place concrete aqueduct
                       body shall meet the requirements of Article 2   7   1 in this specification.
                           2  The pouring sequence of the cast⁃in⁃place concrete aqueduct
                       body can be from one end to the other end, from both ends to the
                       center or from the center to both ends. Aqueducts of small section
                       shall be poured uniformly.
                           3  The aqueduct body shall be divided into several layers ac⁃
                       cording to different types of aqueduct body. The height of each layer
                                                                            1 6 7
   169   170   171   172   173   174   175   176   177   178   179