4　Structure Calculation

4.1　General Requirements

4.1.1　The structure for mobile communication engineering steel tower and mast includes free-standing steel tower，steel pole，guyed steel mast and other types.

4.1.2　The service requirement，surrounding environment，landscape，bearing capacity of buildings，project cost and other factors shall be taken into account for the selection of structure for mobile communication engineering steel tower and mast.

4.1.3　The ultimate limit state of structure for mobile communication engineering steel tower and mast shall be calculated based on the provisions set out in Section 3.1.The wind load and ice load may be calculated as the first variable load in order.When necessary，the seismic checking calculation is required.

4.1.4　The serviceability limit state of structure for mobile communication engineering steel tower and mast shall be calculated based on the provisions set out in Section 3.1.The corresponding variation provisions shall be met.

4.1.5　The corresponding calculation diagram shall be selected based on platform structure type to calculate the internal force and displacement of structure platform for mobile communication engineering steel tower and mast.The tower body may be deemed as the base of platform structure.