Page 191 - Water Standards
P. 191

Table 3   9   5-2  Allowable form production error of spiral
                                           cases and tailwater tube     Unit: mm
                        No.              Item               Spiral case  Tailwater tube
                         1         Form length and width      ±5          ±5
                         2    Height between adjacent board surfaces  3    2
                         3           Local unevenness          5           3
                         4            Face slab crack          2           2

                        Note: Local unevenness means the deviation of a curved form from the design dimensions;
                            the error is checked by a 2m straight ruler for a flat form.
                           2  The equipping of the main items of machinery for concrete
                       transportation and pouring, as well as the productivity they may
                       reach, shall be decided according to the powerhouse characteristics,
                       such as complex structures shape, if there are many embedded parts
                       and much auxiliary work, etc.
                           3  The temperature control measures of the lower part concrete
                       shall meet the requirements in Articles 2   7   23, 2   7   24 and 3   3   6 of
                       this specification.
                           4  When the air temperature suddenly drops during the construc⁃
                       tion of the lower part concrete, the protection of the exposed surfaces
                       of the poured concrete structures shall be strengthened, and the
                       poured holes shall be closed off during the low temperature season.
                       3   9   7  Upper part concrete construction shall meet the following re⁃
                       quirements:
                           1  Upper part structures shall be finished before the crane opera⁃
                       tion.
                           2  An erection bay should be constructed in advance of the unit
                       bay, and the external crane should be used to hoist the crane into
                       place before capping the building, so as to create conditions for the
                       testing and pre⁃assembly of the components of the turbine⁃generators.
                           3  The parts related to the first stage power generation shall be
                         1 8 4
   186   187   188   189   190   191   192   193   194   195   196