3　Basic Requirements

3.0.1　There are many methods for assembly and erection of the steel towers.Construction design and operating manual shall be firstly prepared before the project started，then spread and exploitation after piloting.

3.0.2　The strength in the process of the assembly and erection of stell tower shall be verified.Installation stress of tower components shall be smaller than allowable stress according to the strength of tower.Recommended value of allowable stress of common tower material components are listed as table 3.0.2.

3.0.3　In the process of decomposing construction design of the assembly and erection of steel towers，the maximal stress of the heaviest，much heavier and higher，maximal leaning segments of gin pole shall be respectively calculated，then the maximal value can be used as gist to select implements.

3.0.4　As an important part of the assembly and erection of steel tower，the gin pole shall be made after comparison，based on the characteristics of tower and terrain.

3.0.5　In the assembly and erection of stayed tower integral or decomposing type can be used by means of herringbone drop-down gin pole.

3.0.6　Types of self-supporting tower should use decomposition type.Recommended assembly and erection methods are as follows:

1　Decomposing assembly and erection of steel towers by gin pole outer wire and inner suspension，gin pole inner wire and inner suspension，or outer gin pole.

2　Decomposing assembly and erection of steel towers by ground swing arm gin pole or inner suspension swing arm gin pole.

Other assembly and erection methods shall be tested and examined before operation.

3.0.7　The strength and integral stability of gin pole of the assembly and erection steel towers shall be firstly inspected.The stability safety coefficient of gin pole under pressure is not less than 2.5，while yield safety coefficient is not less than 2.1.

3.0.8　Safety coefficient of hoisting tools of assembly and erection steel tower should meet the standard of DL 5009.2-2004.

3.0.9　The selection methods of assembly and erection steel towers shall reduce earthwork and meet the requirements of environmental protection.

3.0.10　The installation quality of steel towers shall comply with relevant provisions of applicable national related standards.