Page 184 - Water Standards
P. 184

pansion joint should be 1   5-2cm. The quality of pipeline joints and
                       expansion joints shall meet design requirements and the requirements
                       in Section 2   7 of this specification, and hermetic sealing shall be en⁃
                       sured.
                           4  The section length of a precast reinforced concrete pipe is de⁃
                       termined according to specific conditions of process, transportation
                       and installation, and generally should not be longer than 5m. Socket
                       type pipes shall be selected with priority as the pipe section form. Dur⁃
                       ing pipe section hoisting, the concrete strength shall meet the design
                       requirements. When there are no design requirements, it shall not be
                       lower than 70% of design strength. The position, form and sealing
                       material of the settlement joints and expansion joints, and the sealing
                       material of pipe section joints shall all meet the design requirements.
                       The sealing material shall be firmly bonded, and tightly plugged,
                       without leakage phenomenon. The allowable deviation for precast pipe
                       installation shall meet the requirements in Table 3   8   5.
                            Table 3   8   5  Allowable deviation of precast pipe installation
                                                                        Unit: mm

                                                                          Allowable
                        No.                     Item
                                                                          deviation
                         1  Axis displacement of pipes                      ±5
                         2  Internal surface elevation difference between adjacent two pipes  3
                         3  Width of settlement joint and expansion joint   ±5
                         4  Gap difference in the same connecting joint of a socket pipe  ±5
                       3   8   6  The construction of penstocks made of other materials shall
                       meet the following requirements:
                           1  The civil construction of penstocks made of other materials
                       shall be carried out according to design requirements.
                           2  According to the material and performance of different pipe⁃
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