1. Type of communication tower infrastructure.
Communication towers classification is based on a number of considerations, including structural action, which denotes how the tower is erected; cross section, which indicates the shape of the towers (either square, hexagonal, polygonal or triangular); type of material sections, which refers to a tower’s angular or tubular bracings; and type of surface it is placed on.
An important part of the communication tower structure is to transfer the entire load of the superstructure to the foundation and maintain the overall stability of the structure.
The basic selection and basic arrangement of the communication tower are closely related to the structure, structural layout, external load type, construction site and geological conditions. Reasonable basic selection and design are essential to reduce construction costs, shorten construction periods, and ensure structural safety and reliability.
In the communication tower, in addition to the roof tower on the roof, there are space truss towers, single-tube towers and cable towers on the ground. Space truss towers are usually independent foundations, with uniform beams (Fig. 10-1) sharing horizontal loads on the tower, wind loads and seismic effects), weights, etc., controlling horizontal loads.
Since the wind load is a random load, the size and direction of the wind are arbitrary, pulsating, and the basic force is also random and pulsating.
The communication tower of the space steel truss structure is relatively light in weight, while the vertical load of the suspended communication antenna platform is not large, so the improved top surface tension and pressure are submitted under the triangular or quadrilateral truss, and the tension value is generally up to 70 or more. percentage. The tensile design of the truss tower is very important.
The single-tube communication tower is cylindrical (conical); the base is mostly square or round.
The diameter of the single-tube communication tower is very small, so the size of the base is not very large. The edge of the bottom plate can be pulled away from the base by the wind moment. According to the high structural design specification (GB 50135 press release), under the standard combination of normal limit state loads, the foundation ground is not allowed to remove the foundation soil. Therefore, it is necessary to extend the base of the board to enhance the bending ability of the base board. When the foundation is not good, the base is used to pile up the pile.
The two parts of the cable communication tower center and the anchor base of the rope (Figure 10-3). The center base supports the rod body to withstand the pressure and horizontal thrust of the shaft; the ground anchor is fixed and the rope is fixed.
2. The shallow foundation and layout of the communication tower structure.
When the topsoil of the communication tower construction site has good bearing capacity, the foundation deformation can be controlled within an acceptable range. At the same time, the foundation can be shared by the foundation and the overlying soil based on the pulling force, and the shallow foundation form can be adopted.
Space truss towers typically have foundations under each column that are joined together by connecting beams to withstand the tower’s own weight, bending moments and horizontal shear.
In order to resist tensile forces, reinforced concrete slabs, slab extension pedestals, independent foundations under the plane of the floor can be round or rectangular, have a certain thickness, and are double reinforced to withstand bending moments and shearing forces.