Construction Skills Of High Mast Lights

Construction skills of high mast lights involve many aspects, including preliminary preparation, basic construction, lamp pole installation, lamp connection, cable connection, debugging and acceptance, etc. Let's briefly talk about some of the skills below.

1. Preliminary preparation

Survey and design:

Survey the construction site to understand the foundation conditions, underground pipelines, etc. According to the lighting requirements and environmental characteristics, parameters such as pole height and lamp type should be designed. Determine the location and layout of the high mast light to ensure the maximum lighting range.

Material preparation:

Prepare construction materials such as cranes, bolts, wire ropes, cables, etc. Ensure that the quality of materials meets the design requirements to avoid affecting the construction quality due to material problems.

Tool preparation:

Prepare construction tools such as electric drills, wrenches, screwdrivers, etc. Ensure that the tools are complete and in good condition so that they can be used smoothly during the construction process.

2. Foundation construction

Cleaning and pad pouring

After the foundation inspection is completed, remove the surface loose soil and disturbed soil, leave no water, and immediately carry out the pad concrete construction. The pad concrete must be vibrated and compacted, the surface is flat, and it is strictly forbidden to dry the base soil.

Rebar binding

After the cushion layer is poured, the surface is marked with lines for steel bar binding after the concrete reaches 1.2MPa. No missing buckles are allowed in steel bar binding. The hook part of the column dowel must be tied at 45° with the bottom plate reinforcement. All connection points must be tied. The first stirrup is tied 5cm away from the bottom plate, and the last stirrup is tied 5cm away from the top of the foundation as the elevation control reinforcement and positioning reinforcement. Another positioning reinforcement is tied at the top of the column dowel. After the upper and lower stirrups and positioning stirrups are tied, the column dowel is adjusted into place and temporarily fixed with a tic-tac-toe wooden frame, and then the remaining stirrups are tied to ensure that the column dowel does not deform. The two positioning reinforcements must be replaced after the foundation concrete is poured. After the steel bars are tied, protective plastic pads are placed on the bottom and sides. The thickness is the designed protective layer thickness. The spacing between the pads shall not be greater than 100mm (determined by the designed steel bar diameter) to prevent the quality problem of exposed reinforcement. Pay attention to the protection of the finished steel bars. The steel bars shall not be arbitrarily collided with the steel bars to cause the steel bars to shift.

Formwork installation

After the steel bar binding and related professional construction are completed, the formwork is installed immediately. The formwork uses a small steel formwork or a wooden formwork and is reinforced with a rack pipe or a wooden square. When the slope of the conical foundation is less than 30°, an inclined formwork is used for support, and bolts and bottom plate steel bars are used to tighten to prevent floating. There are ventilation and vibration holes on the upper part of the formwork. When the slope is ≤30°, a wire mesh (spacing 30cm) is used to prevent concrete from falling, and a well-shaped wood is set at the top to control the position of the steel bars. It is not allowed to impact the formwork with heavy objects, and it is not allowed to set up scaffolding on the formwork of the hanging side to ensure the firmness and tightness of the formwork.

Cleaning

Remove wood chips, soil, and other debris from the high mast light foundation formwork, water the wooden formwork to moisten it, and seal the board joints and holes.

Concrete pouring

Concrete should be poured in layers and continuously, and the rest time should not exceed the initial setting time of the concrete, generally not more than 2h. To ensure the correct position of the steel bars, first pour a layer of 5-10cm thick concrete to fix the steel bars. Each step of the step-type foundation is poured as a whole. After each step is poured, pause for 0.5 hours to wait for it to sink, and then pour the next layer. Layered material is poured, and the thickness of each layer is the effective vibration length of the vibrator. Prevent honeycombs, rough surfaces or holes caused by excessive material, inadequate vibration or missing vibration, and mortar gushing out from the root of the hanging side.

Concrete vibration

Use an inserted vibrator, and the insertion spacing is not greater than 1.25 times the length of the vibrator's effective part. The upper layer vibrator is inserted into the lower layer 3 to 5 cm. Try to avoid colliding with embedded parts and embedded bolts to prevent the embedded parts from shifting.

Concrete leveling

After the concrete is poured, the concrete with a relatively large surface should be vibrated once with a flat vibrator, then scraped flat with a scraper, and then smoothed with a wooden trowel. The concrete surface elevation must be checked before closing, and any non-compliant parts should be rectified immediately.

Concrete maintenance

The poured concrete should be covered and watered in about 12 hours. Normal temperature curing should not be less than 7 days, and special concrete curing should not be less than 14 days. Special personnel are assigned to inspect and implement the curing to prevent cracks on the concrete surface due to untimely curing.

Formwork removal

The side formwork can be removed only when the concrete strength can ensure that its edges and corners are not damaged by removing the formwork. Before removing the formwork, a special person is assigned to check the concrete strength.

Factors affecting the amount of concrete used

1. Light pole height: The higher the light pole height, the greater the foundation bearing capacity required, and more concrete is required to ensure the stability of the foundation.

2. Foundation design size and depth: The design size and depth of the foundation directly determine the amount of concrete used. Generally speaking, the larger the size and the deeper the depth, the more concrete is required.

3. Geological conditions: Geological conditions have an important impact on foundation construction. In areas with poor geological conditions, it may be necessary to increase the size and depth of the foundation to increase the bearing capacity of the foundation, which will also increase the amount of concrete used accordingly.

Calculate the amount of concrete used

When calculating the amount of concrete used for the foundation of a high pole street lamp, the foundation volume calculation formula πr²h is usually used (where r is the foundation radius and h is the foundation depth). According to the designed foundation size and depth, the required concrete volume can be obtained by substituting it into the formula. It should be noted that there may be certain losses in actual construction, so the loss coefficient should be appropriately considered when calculating.

Notes

1. To make the foundation of a high mast light, you must first determine the location of the lamp and survey the geological conditions. If the surface is soft soil, the excavation depth should be deepened. At the same time, it is necessary to confirm that there are no other facilities (such as cables, pipes, etc.) below the excavation location, and there are no long-term sunshade objects on the top of the street lamp, otherwise, the position should be appropriately changed.

2. The foundation of a 20 meter high mast light is a reinforced concrete structure, designed according to the "Code for Design of Building Foundations" GBJ7-89 and other standards. The basic foundation of a 15 meter high mast light is 1*1M. In fact, the foundation of a high mast light is more complicated than that of other lamp poles. A concrete ground net needs to be made below, and the foundation depth is about 2.5-3 meters. It depends on the actual construction plan.

3. According to the height and weight, diameter, hole diameter, and hole spacing of the high mast light, use anchor screws and threaded steel to make a steel cage corresponding to the bottom of the lamp pole, dig a pit larger than one square meter, put the steel cage in, and then pour concrete with the grade of C30. After a week, the high mast light can be hoisted.

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