Precautions for installation of communication tower

一、Introduction

In the current era of rapid digital development, communication towers, as the key infrastructure to ensure the smooth operation of communication networks, are of self-evident importance. However, the installation of communication towers is a complex and rigorous project that involves multiple links and numerous details. Any negligence in any link may lead to potential safety hazards or affect the normal use of communication towers. To ensure the installation quality of communication towers, the following will elaborate on various precautions in the installation process in detail.

二、Preparatory work before installation

（一）Preparation of the construction site.

1.Site clearing and leveling.

Firstly, a comprehensive and thorough cleaning of the site where the communication tower is to be installed should be carried out. Remove weeds, sundries, construction waste and obstacles that may affect the construction within the site. After that, according to the design requirements of the communication tower, the site should be leveled. For areas with soft soil, the method of layered compaction should be adopted to ensure that the site has sufficient bearing capacity to support the subsequent construction equipment, the stacking of materials and the weight of the communication tower itself. For example, for communication towers with relatively high heights and large self-weights, the site compaction coefficient should meet the corresponding high standards to prevent the problem of uneven settlement.

2.Site planning and layout.

Reasonably divide the construction site into different functional areas, such as the material storage area, the parking area for mechanical equipment, the rest area for construction workers and the construction operation area, etc. The material storage area should be located in a dry, ventilated and easy-to-manage position. Tower materials and connecting parts of different specifications and models should be neatly placed in categories and clearly marked. Meanwhile, protective facilities such as rain shelters should be set up to prevent the materials from getting damp and rusting. The parking area for mechanical equipment should reserve sufficient space to facilitate the entry, exit and parking of equipment like cranes and transport vehicles. It should also be kept away from the material storage area to prevent safety accidents caused by collisions between the equipment and materials during operation. The rest area for construction workers should be equipped with basic living facilities to ensure that the construction workers can have a good rest. And its location should be relatively safe and quiet. The construction operation area should be scientifically planned in combination with the installation positions of the communication tower foundation and the tower body to ensure the smooth connection of various construction processes.

3.Guarantee of site traffic and transportation conditions.

Check the condition of the external roads leading to the construction site, including the width, bearing capacity, road conditions, as well as height and weight limits. If they do not meet the requirements for transporting the components of the communication tower, it is necessary to communicate and coordinate with relevant departments in advance and carry out renovation work such as road widening and reinforcement. Inside the site, plan clear transportation passages. The width of the passages should meet the needs of transport vehicles and large equipment to pass through. The road surface should be hardened. Meanwhile, set up traffic guidance signs and warning signs to standardize the traffic order within the site and avoid accidents such as collisions.

（二）Review of construction drawings and technical data

1.Drawing review

The construction unit should organize professional personnel, such as project managers, technical supervisors, and construction team leaders, to conduct a detailed joint review of the design drawings of the communication tower. Focus on reviewing key contents such as the structural form of the communication tower, the height of the tower body, the size and form of the foundation, the connection methods of various components, and the layout of anchor bolts, to ensure that they match the actual construction site conditions, the surrounding environment and the construction capacity. Meanwhile, carefully check whether there are problems such as unclear markings, dimensional contradictions, and ambiguous technical requirements in the drawings. If any doubts are found, communicate with the design unit in a timely manner and ask them to provide detailed explanations and make modifications and improvements. In addition, pay special attention to reviewing the safety design parts in the drawings, such as the lightning protection and grounding system and windproof measures, to ensure the safety performance of the communication tower after its completion.

2.Technical data collection and learning

Widely collect all kinds of technical materials related to the installation of communication towers, such as relevant national and industrial construction specifications, quality acceptance standards, communication tower product manuals and installation guides provided by manufacturers. Organize construction workers to study these materials in depth so that they can be familiar with the structural characteristics of communication towers, the materials and performance requirements of various components, the installation process flow, the key points of quality control and safety precautions. Especially for newly adopted construction techniques, new materials or communication towers with special structures, targeted learning should be strengthened to ensure that construction workers can accurately master and correctly apply relevant technologies.

（三）Preparation of construction equipment and tools

1.Selection and configuration of mechanical equipment

According to the types of communication towers (such as self-supporting towers, guyed towers, monopole towers, etc.), heights, weights and the actual situation of the construction site, reasonably select the required construction machinery and equipment. For example, for the installation of taller and heavier communication towers, cranes with large lifting capacities, sufficient lifting heights and good stability should be selected, such as crawler cranes or truck cranes. And appropriate models and specifications should be determined according to their performance parameters and requirements for working radii. In addition, concrete mixers, electric welding machines, steel bar processing machinery, leveling instruments, theodolites, total stations and other measuring instruments as well as various transport vehicles also need to be equipped. Moreover, the number of equipment should be reasonably configured according to the construction schedule plan and the working efficiency of each piece of equipment to avoid the situation where idle equipment or insufficient equipment affects the construction progress.

2.Tool inspection and calibration

Conduct a comprehensive inspection on all kinds of hand tools used in the construction process, such as wrenches, screwdrivers, pliers, etc., to check whether there are damages, deformations or other problems. Tools with problems should be repaired or replaced in a timely manner to ensure that they can be used normally. For measuring tools, such as leveling instruments, theodolites, total stations, as well as various tape measures and calipers, they should be sent to professional metrological verification institutions regularly for calibration to ensure that their measurement accuracy meets the construction requirements. For example, the mean accidental error in the difference in elevation per kilometer for a leveling instrument should not exceed the specified value. The standard deviation in the horizontal direction for one measurement set of a theodolite also needs to meet the corresponding standards. The angle measurement accuracy and distance measurement accuracy of a total station must also meet the standards. Before construction, the measuring tools should be verified on site to provide reliable data support for construction measurement.

（四）Construction personnel organization and training

1.Personnel qualification review

Strictly examine the professional qualification certificates of all kinds of construction personnel involved in the installation of communication towers to ensure that they have the operation qualifications for corresponding positions. For example, crane operators must hold valid special equipment operator certificates (crane operation licenses), and the operation categories and items on the certificates should match the types of cranes they operate. Welders should hold welder operation licenses and possess corresponding welding qualification levels, such as steel structure welding qualifications. Other special operation personnel like scaffolders and electricians also need to have corresponding valid qualification certificates. Register and file the qualification certificates of construction personnel, establish personnel qualification archives for easy access and management at any time. For those whose qualification certificates are about to expire, remind and urge them in advance to handle the extension procedures.

2.Safety and technical training

Organize construction workers to carry out comprehensive safety and technical training activities. The safety training covers contents such as the safety management system on the construction site, safety operation procedures, the correct usage methods of personal protective equipment, various safety accident prevention measures and emergency rescue plans. Through playing warning education videos on safety accidents and explaining typical cases on site, the safety awareness and self-protection ability of construction workers can be enhanced. The technical training focuses on detailed explanations of specific installation techniques, construction processes, quality control standards and key operation points of each process for communication towers. For example, in the process of binding foundation steel bars, the training includes how to accurately control the spacing, position, binding methods of steel bars and the setting requirements for the thickness of the steel bar protective layer. In the tower body installation stage, technical key points such as the assembly sequence of different types of communication towers, the torque requirements for bolt connections and the methods for controlling perpendicularity are explained. After the training, assessments will be carried out. Only those who pass the assessments can participate in the actual construction.

三、Precautions for construction of communication tower foundation

（一）Basic positioning and layout

1.Review of measurement control points

Before positioning the foundation of the communication tower, it is necessary to recheck the measurement control points around the construction site (such as national control points, urban traverse points, etc.). Use high-precision measurement instruments like total stations or GPS receivers to accurately measure the coordinates and elevations of the control points in accordance with the requirements of measurement specifications, and then conduct comparative analysis with the known data. If it is found that the deviation of the control points exceeds the allowable range (generally, the deviation of plane coordinates should not exceed ±10mm, and the elevation deviation should not exceed ±5mm), it is necessary to communicate and coordinate with the local surveying and mapping management department or the construction unit in a timely manner to obtain accurate control point data again or adopt other reliable control points for leading surveying to ensure that the basic positioning reference data is accurate.

2.Basic laying out operation

Based on the rechecked measurement control points, use the theodolite, total station combined with a steel tape to accurately mark out the center line, contour line of the communication tower foundation and the position line of the anchor bolts according to the requirements of the design drawings. During the setting-out process, adopt the method of multiple measurements and mutual verification to ensure the position accuracy of each line. For example, the deviation of the center position of the anchor bolts generally should not exceed ±5mm, and the deviation of the foundation axis should be controlled within ±10mm. To facilitate identification and inspection during the construction process, clearly mark the marked-out lines with wooden stakes, iron nails, paint, etc. At the same time, set up protective devices for the measurement control points to prevent them from being damaged or moved, so that subsequent construction can be rechecked and calibrated against the control points at any time.

（二）Foundation excavation

1.Selection of excavation method

Taking into comprehensive consideration factors such as the types of communication tower foundations (such as independent foundations, raft foundations, pile foundations, etc.), the geological conditions of the construction site (soil types, soil layer distribution, groundwater level, etc.) and the surrounding environment, select appropriate foundation excavation methods. If the geological conditions are good, the groundwater level is low and the foundation burial depth is shallow, a method mainly relying on mechanical excavation supplemented by manual bottom cleaning can be adopted to improve the excavation efficiency and ensure the flatness of the foundation base and the dimensional accuracy. However, if the geological conditions on the construction site are complex, with soft soil layers, quicksand layers or a relatively high groundwater level, corresponding special excavation measures need to be taken. For example, in soft soil conditions, support methods such as steel sheet pile support and cement mixing pile water-stop curtain should be combined with dewatering measures like well point dewatering or deep well dewatering before excavation is carried out, so as to prevent problems such as slope collapse and water gushing from the foundation base and ensure that the foundation excavation work can be carried out safely and smoothly.

2.Excavation size and depth control

During the foundation excavation process, strictly follow the foundation dimensions and depths specified in the design drawings for construction. Use measuring tools such as leveling instruments and steel tapes to regularly measure the excavation depth to prevent over - excavation or under - excavation. Over - excavation can damage the original soil structure of the foundation base, reducing its bearing capacity. Backfilling is required in such cases, but it is difficult for the backfilled soil to meet the standards of the original soil, which may easily lead to problems such as foundation settlement. Under - excavation, on the other hand, cannot meet the requirements for the foundation embedment depth, affecting the stability of the communication tower. Generally, the allowable deviation of the foundation excavation depth should be controlled within ±100mm, and the deviation of the excavation dimensions (in the length and width directions) should be controlled within ±50mm. Regarding the excavated earthwork, it should be reasonably piled up according to the actual situation of the site. If the site allows, it can be piled up at a certain safe distance from the edge of the foundation excavation area for later backfilling. If the site is narrow, it should be promptly transported away from the construction site to avoid affecting subsequent construction operations and site traffic.

（三）Reinforcement works

1.Reinforcement procurement and inspection

According to the requirements of the design drawings, select steel bar suppliers with qualified quality and good reputation for procurement to ensure that the varieties, specifications, grades, brands, etc. of the steel bars are completely consistent with the design requirements. For example, for the commonly used HRB400 grade steel bars, their mechanical property indexes such as yield strength, tensile strength, elongation rate and chemical compositions should all comply with the corresponding national standards. When the steel bars enter the construction site, sampling inspections should be carried out according to the specified batches and quantities. The inspection contents include appearance inspection and mechanical property tests. The appearance inspection mainly checks whether there are defects such as cracks, knots, folds, oil stains on the surface of the steel bars. The mechanical property tests need to detect the yield strength, tensile strength, elongation rate, cold bending performance of the steel bars, etc. Only those that pass the inspection can be used for foundation construction, and the unqualified steel bars must be returned and removed from the site.

2.Reinforcement processing and binding

Before steel bar processing, carry out processing operations such as straightening, rust removal, cutting and bending on the steel bars in accordance with the requirements of the design drawings and specifications. The steel bars should be straightened by mechanical straightening methods to avoid changing the mechanical properties of the steel bars through tensile straightening. The cutting length of the steel bars should be accurate, and the error should be controlled within the allowable range (generally not exceeding ±10mm). The bending and forming of the steel bars should meet the requirements for the bending angle and bending radius specified in the design. For example, when the end of HPB300 grade steel bars is made into a 180° hook, the diameter inside the curved arc of the hook should not be less than 2.5 times the diameter of the steel bar, and the length of the straight part after bending of the hook should not be less than 3 times the diameter of the steel bar. During the steel bar binding process, operate strictly in accordance with the steel bar spacing and position required by the design drawings to ensure that the steel bars are arranged neatly and evenly. Appropriate binding wires (such as No. 20 - 22 galvanized iron wires) and binding methods (such as cross binding, figure-eight binding, etc.) should be adopted to ensure that the steel bar binding is firm and prevent the steel bars from shifting during the concrete pouring process. Meanwhile, set a sufficient number of steel bar spacers and supports to ensure that the thickness of the steel bar protective layer meets the design requirements. Generally, the thickness of the protective layer for the foundation slab steel bars is 40 - 70mm (determined according to the specific design). Through the spacers and supports, keep an appropriate distance between the steel bars and the formwork to avoid quality problems such as exposed steel bars on the concrete surface caused by the direct contact of the steel bars with the formwork.

（四）Template Engineering

1.Template selection and installation

Select appropriate formwork materials and forms according to the shape, size, structural characteristics and construction process requirements of the communication tower foundation. Common ones include wooden formwork, steel formwork, plywood formwork, etc. Wooden formwork is easy to process and low - cost, but has a limited number of turn - around uses. Steel formwork has high strength and can be reused many times, but requires a large initial investment. Plywood formwork combines the advantages of both and is widely used. During the formwork installation process, ensure that the formwork joints are tight. Materials such as sealing strips and sponge strips can be used to fill the joints to prevent grout leakage during concrete pouring. At the same time, make sure that the flatness and perpendicularity of the formwork meet the requirements. Use measuring tools such as leveling instruments and straightedges for inspection and control. Generally, the deviation of the formwork surface flatness should not exceed 5mm, and the perpendicularity deviation should not exceed 3mm to ensure the appearance quality of the foundation concrete. In addition, firmly reinforce the formwork. By setting tie - bolts, steel pipe supports, wooden square backings, etc., enhance the overall stability of the formwork so that it can withstand the lateral pressure and vibration force during the concrete pouring process and avoid problems such as formwork deformation and formwork swelling.

2.Formwork removal

The time for formwork removal should be determined strictly in accordance with the growth of concrete strength as well as the requirements of the design and specifications. Non-load-bearing formwork (such as the formwork on the side of the foundation) can generally be removed when the concrete strength reaches above 2.5MPa, which can be judged through the compressive strength test of the specimens cured under the same conditions. Load-bearing formwork (such as the formwork of the foundation slab) needs to be removed only after the concrete strength reaches a certain proportion (such as 70% - 100%, specifically according to the design requirements) of the designed strength according to the designed strength grade of the concrete and the stress situation of the structure. When removing the formwork, operate in the correct sequence. First, remove the reinforcement components such as supports and tie bolts, and then gently pry the formwork to make it separate from the concrete surface, avoiding excessive force that may cause quality problems such as cracks and missing edges or corners on the concrete surface. The removed formwork should be cleaned, repaired and maintained in a timely manner to facilitate its reuse in the next cycle, improve the utilization rate of the formwork and reduce the construction cost.

（五）Concrete Work

1.Concrete mix design

Based on the designed strength grade and durability requirements (such as anti-permeability, anti-freezing, etc.) of the communication tower foundation as well as the situation of raw materials (cement, sand, gravel, admixtures, etc.) on the construction site, the concrete mix proportion design is carried out by laboratories with corresponding qualifications. During the design process, multiple factors such as the workability, strength and durability of the concrete are taken into comprehensive consideration. Through trial mixing, adjustment and other links, the optimal proportion of the usage amounts of various raw materials is determined. For example, for the foundation concrete with anti-permeability requirements, appropriately increase the amount of cement used and select suitable admixtures (such as waterproofing agents, air-entraining agents, etc.) to improve the compactness and anti-permeability performance of the concrete. For mass concrete of the foundation, consider adopting measures such as using low-heat cement, adding mineral admixtures like fly ash and optimizing the grading of coarse and fine aggregates to reduce the heat of hydration of the concrete and prevent temperature cracks caused by excessive temperature differences between the inside and outside of the concrete. Meanwhile, verification tests should be carried out on the designed mix proportion. Only when it is ensured that all performance indicators of the concrete meet the design requirements can it be used for actual construction.

2.Concrete mixing and transportation

Use a concrete mixer that meets the requirements for mixing operations. Before mixing, accurately weigh various raw materials according to the mix proportion to ensure that the measurement error is within the allowable range (such as cement, water, and additives, the measurement error generally does not exceed ± 2%, and sand and stone measurement error does not exceed ± 3%). The mixing time is reasonably determined based on factors such as the type of mixer and the slump of the concrete. Generally, the mixing time of a forced mixer is not less than 90 seconds to ensure uniform mixing of the concrete and thorough mixing of all components. During the transportation of concrete, appropriate transportation vehicles (such as concrete mixer trucks, concrete transfer pumps, etc.) should be selected, and effective measures should be taken to prevent concrete segregation, slump loss, and other situations. For example, when using a concrete mixer truck for transportation, the tank should be kept continuously rotating to ensure that the concrete is in a uniform mixing state during transportation; For long-distance transportation or transportation in high temperature weather, the slump of concrete can be adjusted appropriately, while shortening the transportation time to ensure that the concrete can still meet the pouring requirements when it is transported to the construction site.

3.Concrete pouring and vibration

Before pouring concrete, check the foundation formwork, steel bars, etc. again to ensure that the formwork is installed firmly, the joints are tight, the position and spacing of the steel bars meet the design requirements, and clean up any debris, accumulated water, etc. inside the formwork. During pouring, follow the pre established plan. For situations with large foundation areas, layered pouring, segmented pouring, and other methods can be used to ensure that the concrete can evenly and continuously fill the entire foundation space and avoid cold joints. Vibration is a key step in ensuring the compactness of concrete. Suitable vibration tools should be selected according to different parts of the foundation. For example, immersion vibrators are commonly used for foundation columns, walls, and other parts, while flat plate vibrators are suitable for larger and thinner areas such as foundation slabs. During vibration, the vibration time and spacing should be strictly controlled. The insertion depth of the immersion vibrator should be appropriate, and the vibration spacing should generally not exceed 1.5 times its effective radius. The vibration time should be based on the concrete surface no longer sinking, no more bubbles emerging, and the surface overflowing with cement slurry to prevent over vibration from causing concrete segregation or leakage, resulting in quality defects such as honeycomb and rough surface inside.

4.Concrete curing

Timely maintenance work is crucial for improving the strength and durability of concrete after pouring is completed. The maintenance methods can be selected according to the actual situation, such as covering moisturizing maintenance, watering maintenance, spraying maintenance agents, etc. For example, in high temperature and dry air environments, covering with plastic film and regularly sprinkling water can be used to keep the concrete surface always moist; During construction in cold seasons, insulation measures should be taken to prevent concrete from freezing, and insulation materials such as cotton quilts can be covered. The curing time should meet the regulatory requirements. Generally, the curing time for ordinary concrete should not be less than 7 days, and for concrete with special requirements such as impermeability and frost resistance, the curing time should not be less than 14 days. During the maintenance period, assign a dedicated person to be responsible for regularly inspecting the concrete curing situation, ensuring that the curing measures are implemented properly, and creating favorable conditions for concrete hardening and performance improvement.

四、Precautions for installation of communication tower body

（一）Tower material inspection and stacking

1.Inspection of tower materials upon arrival

After the tower materials are delivered to the construction site, strict incoming inspection must be carried out. Check carefully against the design drawings whether the specifications, models and quantities of the tower materials are accurate. Inspect the appearance quality of each member and each connecting piece to see if there are defects such as deformation, rust and cracks. For example, for the angle steel materials of the tower body, if obvious bending deformation is found and the height of the bending deflection exceeds the allowable deviation range (generally, it is stipulated that the height of the bending deflection within each meter of length should not exceed 3mm, etc.), they cannot be directly used for installation and need to be straightened or replaced. Meanwhile, the quality of the galvanized layer of the tower materials should be inspected. For those with damages such as peeling and flaking of the galvanized layer, it is also necessary to decide whether replacement is needed according to the severity of the situation, because the galvanized layer plays a crucial role in the anti-corrosion and anti-rust of the tower materials. If the quality is poor, it will affect the service life of the communication tower.

2.Management of tower material stacking

For the tower materials that have passed the inspection, stack them according to their specifications and models. Select a site that is flat, solid and has good drainage as the stacking area to avoid rusting of the tower materials caused by water accumulation on the site. When stacking, ensure that the tower materials are placed neatly. Appropriate gaps should be left between tower materials of different specifications to facilitate access and also prevent deformation or damage caused by mutual compression. For longer and heavier tower materials, appropriate supporting and padding methods should be adopted. For example, sleepers can be used to raise them to ensure ventilation at the bottom of the tower materials. Moreover, the number of stacking layers should be reasonably controlled to avoid excessive stacking that may cause the tower materials on the bottom layer to deform due to excessive pressure. In addition, protective measures against rain and moisture should be taken. A simple rain shelter can be built in the stacking area to prevent rainwater from directly dripping onto the tower materials and eroding the galvanized layer, which would affect their quality and service life.

（二）Tower assembly

1.Selection and layout of assembly site

Select an open, flat site that is convenient for crane operations as the tower body assembly site. The size of the site should be reasonably determined according to factors such as the scale of the communication tower, the assembly method and the working radius of the crane. The site should be kept away from obstacles such as high-voltage lines and buildings to ensure that the crane has sufficient safe space during operations like lifting and rotating, and to avoid collision accidents. Within the assembly site, an assembly platform with a levelness that meets the requirements should be set up. Generally, it can be measured and adjusted by using a leveling instrument to ensure that the flatness error of the platform is controlled within a small range (for example, not exceeding 5mm). This is conducive to accurately assembling the tower body components and improving the assembly accuracy. Meanwhile, obvious warning signs should be set up around the site, such as enclosures, warning lights, warning slogans, etc., to prevent unauthorized personnel from entering and ensure the safe progress of the assembly work.

2.Assembly sequence and method

Strictly follow the assembly sequence stipulated in the design and installation manual of the communication tower for operation. Usually, the assembly is carried out step by step from the bottom to the top. First, accurately connect the foundation section with the anchor bolts to ensure that the connection is firm and the position is accurate. The perpendicularity, levelness and other indicators can be checked by using measuring instruments. Then, install each tower body section layer by layer. During the assembly process, appropriate tooling fixtures should be used. For example, when conducting bolt connections, use special tools such as wrenches and sockets to ensure that the bolts can be tightened according to the specified torque values. Moreover, re-tightening and final tightening operations should be carried out to enhance the reliability of the bolt connections and prevent potential safety hazards caused by bolt loosening during the subsequent operation of the tower body.

For some large and complex communication towers, it may be necessary to adopt the method of overall hoisting after segmented assembly. At this time, special attention should be paid to the alignment accuracy between each segment. Through operations such as adjustment and alignment, ensure that each segment can be closely and accurately connected together. And before the overall hoisting, conduct a comprehensive inspection and reinforcement on the assembled segments to ensure their structural stability and avoid problems such as deformation and falling apart during the hoisting process.

（三）Tower body lifting

1.Crane selection and positioning

Carefully select a crane with an appropriate model, lifting capacity and lifting height that meet the requirements according to factors such as the height, weight of the communication tower body and the segmented situation after assembly. When choosing a crane, not only its rated lifting capacity should be considered, but also its performance indicators such as working radius, lifting height and stability should be paid attention to, ensuring that the crane can successfully complete the tasks in each stage of the tower body hoisting. For example, for taller communication towers, it may be necessary to choose large-tonnage truck cranes or crawler cranes, and reasonably configure parameters such as the boom length of the crane according to the actual situation on the site.

The standing position of the crane should be planned reasonably, fully considering factors such as the bearing capacity of the site, surrounding obstacles and the hoisting operation radius. The outriggers of the crane must be supported on solid and flat ground. For soft ground, reinforcement measures such as laying steel plates and sleepers should be taken to prevent the crane from overturning during the hoisting process due to ground subsidence. Meanwhile, accurately calculate the working radius of the crane to ensure that it can operate freely when hoisting various parts of the tower body, and maintain a sufficient safe distance from surrounding buildings, high-voltage lines, etc., to avoid safety accidents caused by collisions.

2.Safety measures for lifting operations

Before hoisting the tower body, conduct a comprehensive inspection of the crane, including the wear condition of mechanical components, the wear and wire breakage situation of the wire rope, and the wear and deformation condition of the hook, etc., to ensure that the crane is in good working condition. Formulate a detailed hoisting operation plan, clearly define the hoisting sequence, command signals, personnel division of labor and other contents, and organize the personnel involved in the hoisting operation to study and receive technical disclosures to ensure that everyone is clear about their responsibilities and operation requirements. During the hoisting process, there should be a dedicated person to conduct unified command. The commander should possess rich hoisting experience and professional knowledge, and communicate with the crane operator through clear and definite command signals such as walkie-talkies and semaphore. The crane operator must operate strictly in accordance with the command signals and shall not act without authorization. Meanwhile, set up a warning area at the hoisting site, use warning lines, warning signs, etc. to keep unauthorized personnel outside the warning area, and arrange dedicated personnel to be responsible for guarding to prevent people from accidentally entering the dangerous hoisting area. In addition, effectively bind and fix the tower body, select appropriate lifting points and binding methods to ensure that the tower body will not shake, slip or other situations occur during the hoisting process, and guarantee the safe and smooth progress of the hoisting operation.

（四）Verticality correction of tower body

1.Verticality measurement method

During the installation process of the tower body and after the installation is completed, the perpendicularity of the tower body should be measured in a timely manner to ensure that it complies with the relevant specification requirements. Commonly used measurement methods include the theodolite measurement method, the total station measurement method, etc. By setting observation points at different heights of the tower body and conducting measurements from different directions, the perpendicularity deviation data of the tower body can be obtained. For example, for a self-supporting communication tower, when the tower body rises to a certain height (such as about every 10 meters), the perpendicularity can be measured with a theodolite in two mutually perpendicular directions. Record the measurement data and compare it with the allowable deviation value specified in the design. Generally speaking, the perpendicularity deviation of the communication tower body should not exceed 1/1500 of the tower height (there may be slight differences for different types and different specification requirements). If it is found that the measurement data exceeds the allowable deviation range, correction measures should be taken in a timely manner to ensure the perpendicularity of the tower body, thereby ensuring the overall structural stability of the communication tower and the accuracy of communication signal transmission.

2.Verticality correction measures

If the measurement reveals that there is a deviation in the perpendicularity of the tower body, corresponding correction measures should be taken according to the direction and magnitude of the deviation. For smaller deviations, fine adjustments can be made by adjusting the tightness of the nuts on the anchor bolts. When operating, turn the nuts of the anchor bolts evenly and slowly, and observe the change in perpendicularity through measuring instruments while making adjustments to prevent over-adjustment.

For larger deviations, tools such as jacks may be needed to push and correct the tower body. When using jacks, appropriate pushing positions and directions should be selected, and reliable support and protection measures should be set up at the corresponding parts of the tower body to avoid causing damage to the tower body during the pushing process. The correction process should be carried out slowly and steadily, with measurements being taken simultaneously during the correction to ensure that the perpendicularity of the tower body gradually returns to the allowable range. After the correction is completed, the anchor bolts and other components should be tightened again to ensure the stability of the tower body and prevent any subsequent changes in perpendicularity.

五、Precautions for installation of communication tower ancillary facilities

（一）Antenna and feeder installation

1.Determination of antenna installation position and angle

The installation position and angle of the antenna play a crucial role in the coverage effect of communication signals. They need to be accurately determined according to factors such as the coverage requirements of the communication network, the surrounding environment (such as the distribution of buildings, topography and landforms, etc.) and the direction of signal transmission. Usually, professional network planning software is used for simulation analysis, and combined with on-site actual tests to determine the optimal installation plan. For example, in urban areas, the situation of signal blocking by surrounding high-rise buildings should be considered, and the elevation angle and azimuth angle of the antenna should be reasonably adjusted to achieve effective coverage of the target area. In mountainous areas, the direction of the antenna should be determined according to the trend of mountain ranges and the distribution of villages to improve the range and quality of signal coverage.

When installing the antenna, it is necessary to ensure that it is firm and reliable. Use appropriate clamps, brackets, etc. to fix the antenna at the designated position on the tower body. The size of the clamp should match the pipe diameters of the antenna and the tower body. When tightening the bolts, the specified torque value should be reached to prevent the antenna from shifting or loosening due to external forces such as wind blowing and vibration, which may affect the stable transmission of communication signals.

2.Installation and connection of feeder lines

The installation of feeder lines should be neat and orderly, avoiding situations such as crossing and winding. Reasonable routing paths should be planned along the tower body, and appropriate fixing methods should be adopted. For example, feeder line clamps can be used to fix the feeder lines on the tower body at certain intervals (generally 1 - 2 meters) to prevent the feeder lines from slipping due to their own weight or external forces. When the feeder lines are bent, the requirements for their minimum bending radius should be followed (different types of feeder lines have different requirements) to avoid excessive bending that may damage the internal structure of the feeder lines and affect the signal transmission performance.

The connections between the feeder lines, antennas and equipment should be tight and reliable. Connectors that meet the standards should be selected, and the connection operations should be carried out strictly in accordance with the operating procedures to ensure good contact at the connection parts. Meanwhile, sealing treatments such as waterproof and moisture-proof should be done well. At the joints of the feeder lines, special waterproof tapes, sealants and other materials can be used for multi-layer winding and sealing to prevent rainwater, fog and other substances from entering the inside of the feeder lines, causing problems such as signal attenuation or short circuits, and ensuring the high-quality transmission of communication signals.

（二）Installation of lightning protection facilities

1.Installation of lightning rod

Lightning rods that meet the specification requirements should be installed on the top of the communication tower. The tip of the lightning rod should be higher than other components of the communication tower to ensure that it can receive lightning first and introduce the lightning current into the earth. The material, height and shape of the lightning rod should comply with relevant lightning protection design standards. Its installation should be firm and reliable, and there should be a good electrical connection with the tower body. Generally, welding or special connection fixtures are used for connection, and the connection part should ensure that the contact resistance meets the requirements (generally, it is required not to exceed 0.03Ω, etc.) to ensure that the lightning current can be smoothly conducted to the earth through the tower body. During the installation process, attention should be paid to the installation angle and position of the lightning rod so that it can provide all-round protection for the communication tower and its affiliated facilities and avoid lightning protection blind spots. Meanwhile, regular inspections and maintenance should be carried out on the lightning rod to check whether there are damages, corrosions and other situations, ensuring that its lightning protection performance is always in a good state.

2.Installation of lightning protection down conductor

The lightning down conductor is an important channel for conducting the lightning current received by the lightning rod to the grounding device. Its quantity, specifications, and laying methods must be strictly implemented in accordance with the lightning protection design specifications. Generally, multiple (such as 2 - 4) down conductors can be used for communication towers. The down conductors should be laid vertically along the tower body, and it is necessary to ensure that their spacing is uniform, the path is the shortest, and bends are minimized as much as possible. The materials of the down conductors usually choose hot-dip galvanized flat steel or round steel, etc. Their specifications should meet the requirements of being able to carry the lightning current (for example, when using hot-dip galvanized flat steel, the cross-sectional area is generally not less than 48 square millimeters).

At the connection parts of the down conductor with the tower body and the grounding device, reliable welding or bolt connection methods should be adopted to ensure that the connection is firm and the electrical conduction is good. Meanwhile, necessary protective measures should be taken for the down conductor to prevent it from being affected by mechanical damage, corrosion, etc. Regularly check the appearance and connection situation of the down conductor, discover and handle existing problems in a timely manner to ensure the normal operation of the lightning protection system.

3.Installation of grounding device

The grounding device is a key component of the entire lightning protection system, and its function is to safely discharge the lightning current into the earth. Generally, the grounding device consists of two parts: the grounding electrode and the grounding conductor. The grounding electrode can adopt an artificial grounding electrode (such as a steel pipe grounding electrode, an angle steel grounding electrode, etc.) or use the foundation reinforcement of the building as a natural grounding electrode. The burial depth, quantity, and spacing of the grounding electrode should meet the requirements of the design and specifications (for example, the burial depth of an artificial grounding electrode is generally not less than 0.6 meters).

The grounding conductor should reliably connect the lightning down conductor with the grounding electrode. Its material and specifications should also comply with relevant standards, and it is necessary to ensure that the contact resistance at the connection part is small enough. After the installation of the grounding device is completed, a grounding resistance tester should be used to measure its grounding resistance. The value of the grounding resistance should meet the specified requirements (generally, the requirement for the grounding resistance of a communication tower is not more than 10Ω). If the grounding resistance does not meet the requirements, timely measures should be taken for rectification, such as increasing the number of grounding electrodes and improving the soil resistivity, to ensure that the lightning protection system of the communication tower can effectively play its role and guarantee the safety of the communication tower, surrounding facilities and personnel.

六、Acceptance and maintenance precautions after installation

（一）Acceptance work

1.Basis and standards for acceptance.

After the installation of the communication tower is completed, the acceptance work shall be carried out strictly in accordance with the relevant national and industrial standards, specifications and the requirements of design documents. The main standards referred to include the "Code for Design of High-rise Structures", the "Standard for Acceptance of Construction Quality of Steel Structure Engineering", the "Code for Design of Lightning Protection and Grounding Engineering of Telecommunication Bureau (Station)" and so on. The acceptance contents cover all aspects such as the foundation, tower body, affiliated facilities and lightning protection system of the communication tower.

During the acceptance, it is necessary to compare with the design drawings to check whether the structural form, dimensions, height, etc. of the communication tower are consistent with the design, whether the installation positions and connection methods of various components meet the requirements, and whether the quality and specifications of materials meet the standards, so as to ensure that the overall quality of the communication tower complies with the predetermined design and specification standards.

2.Acceptance process and methods.

The acceptance work is generally divided into several stages, including the self-inspection by the construction unit, the preliminary inspection by the supervision unit and the final acceptance organized by the construction owner. After completing the installation, the construction unit should first organize technical personnel and construction workers to conduct a comprehensive self-inspection in accordance with the acceptance standards. Timely rectifications should be made for the problems found, and after the rectifications are completed, an application for preliminary inspection should be submitted to the supervision unit.

Upon receiving the application, the supervision unit should conduct a detailed inspection and detection of the communication tower. Methods such as measurement and testing should be used to verify key indicators such as the strength of the foundation, the perpendicularity of the tower body and the grounding resistance of the lightning protection system. For the non-conformities found during the preliminary inspection, the construction unit is required to make rectifications within a time limit. After the rectifications are qualified, the supervision unit shall report the situation of the preliminary inspection to the construction owner.

The construction owner organizes relevant parties such as the design unit, the construction unit and the supervision unit to conduct the final acceptance. Through various means such as reviewing materials (such as construction records, material inspection reports, acceptance records of concealed works, etc.), on-site inspections and functional tests, a comprehensive assessment of the overall quality and performance of the communication tower is carried out. After the acceptance is qualified, an acceptance report will be issued, and then the communication tower can be officially put into use.

（二）Maintenance work

1.Contents of regular inspections

After the communication tower is put into use, a regular inspection system should be established, and special personnel should be arranged to conduct regular inspections and maintenance on the communication tower. The inspection contents include the appearance inspection of the tower body to check whether there are deformations, corrosions, paint peeling and other situations. For the slight corrosions found, rust removal and paint repair should be carried out in a timely manner. Check the connection parts of the tower materials, such as whether the bolts are loose or missing. If any problems are found, tighten or supplement the bolts in time.

Inspect the affiliated facilities such as antennas and feeder lines, check whether the positions and angles of the antennas have changed, and whether the feeder lines are damaged or aged, etc., to ensure that their communication functions are normal. Check the components of the lightning protection system such as lightning rods, down conductors and grounding devices to see if there are problems such as damage and corrosion. Regularly measure the grounding resistance to ensure that the lightning protection system is always in a good working state.

2.Maintenance and repair measures.

According to the problems found during the inspection, corresponding maintenance measures should be taken in a timely manner. For the corrosion problem of the tower body, it can be dealt with by grinding to remove rust and then applying anti-corrosion paint. For loose bolts, they should be re-tightened according to the specified torque value. For the damaged parts of the feeder line, the damaged feeder sections should be replaced in time or effective repair measures should be taken, such as using waterproof tape, heat-shrinkable tubes, etc. for sealing and repair.

Before and after severe weather (such as strong winds, heavy rain, thunder and lightning, ice and snow, etc.), the inspection of the communication tower should be strengthened. Focus on checking the structural stability of the tower body, the firmness of the affiliated facilities and the effectiveness of the lightning protection system, etc. Discover and handle potential safety hazards in a timely manner to ensure that the communication tower can continuously and stably provide support for the communication network.

In conclusion, all aspects of the communication tower installation are closely linked. Each precaution is related to the quality and safety of the communication tower. Relevant construction personnel and managers must strictly follow the above content to ensure that the communication tower can be installed smoothly and operate reliably for a long time, thus laying a solid foundation for the development of the communication industry.