Page 192 - Water Standards
P. 192
constructed in advance.
4 Simply supported beam structures should be used for the
crane beam for the convenience of the prefabrication and installation.
The hoisting shall meet the relevant requirements in Section 2 9 of
this specification.
5 For the construction of the main roof beam, the stiff self⁃sup⁃
porting framework method, a upper load bearing framework or a
through type load bearing framework should be adopted. When the
hoisting conditions are available, precast roofs shall be the priority for
selection.
6 When the method of stiff self⁃supporting framework or load
bearing framework is adopted in construction, their strengths and
stiffnesses shall be designed to ensure enough stability and
construction convenience. The camber shall be set according to design
requirements in construction.
7 Reinforced concrete precast slabs should be adopted for the
roof, and roof waterproofing shall be done well.
8 The reinforced concrete bents in the switch yard should be
constructed with precast ones and installed.
3 9 8 Second stage concrete in powerhouse construction shall meet
the following requirements:
1 Second stage concrete in the powerhouse shall meet the provi⁃
sions in Section 2 7 of this specification, as well as the following re⁃
quirements:
1) The strength of the second stage concrete should be 5MPa
higher than that of the first stage concrete.
2) The aggregate size shall not be larger than 1 / 4 of the
thickness of the smallest structure of the second stage con⁃
crete, or 1 / 2 of the smallest clear spacing between the
steel bars (or embedded parts).
1 8 5