There are four main strategies for the erection of steel transmission towers that are delineated  below:

Build-up technique or Piecemeal technique.

• Section technique.
• Ground assembly technique.
• Helicopter technique.

This technique is most typically employed in an Asian country for the erection of half-dozen.6 kV, 132 kV, 220 potential unit and four hundred potential unit line towers because of the subsequent benefits :

• Tower materials are often equipped to the website in a knocked down condition that facilitates easier and cheaper transportation.
• It doesn't need any significant machinery like cranes etc.
• Tower erection activity is often exhausted any reasonable parcel and principally throughout the year.
• Availability of workmen at low-cost rates.
• This technique consists of erection the towers, member. The tower members are unbroken on ground serially in line with erection sequence to avoid search or time loss. The erection progresses from rock bottom upwards. The four main corner leg members of initial|the primary} section of the tower ar first erected and bauble off. generally, quite one contiguous leg sections of every corner leg are secured along at the bottom and erected.
  

The cross braces of the primary section that are already assembled on the bottom are raised one by one as a unit and secured to the already erected corner leg angles. the initial section of the lower therefore designed and horizontal struts (belt members) if any, are secured in position. For grouping the second section of the tower, 2 gin poles are placed one every on the highest of diagonally opposite corner legs. These 2 poles are used, for raising elements of the second section. The leg members and braces of this section are then hoisted and assembled. The gin poles are then shifted to the corner leg members on the highest of the second section to lift the elements of the third section of the lower position for assembly. Gin poles are, therefore, touched up because the tower grows. This method is sustained until the entire tower is erected. Cross-arm members are assembled on the bottom and raised up and glued to the most body of the tower. For heavier towers, the atiny low boom is square-rigged on one of the tower legs for hoisting functions. The members/sections are hoisted either manually or by winch machines operated from the bottom. For smaller base towers/vertical configuration towers one gin pole is employed rather than 2 gin poles. so as to keep up speed and potency, a tiny low assembly party goes earlier than the most erection gang and its purpose is to arrange the tower members, keeping the members in correct position on the bottom and grouping the panels on the bottom which may be erected as an entire unit.

In the section technique, major sections of the tower are assembled on the bottom and also the same ar erected as units. Either a mobile crane or a gin pole is employed. The gin pole used is just about ten m long and is control in situ by suggests that of men by the aspect of the tower to be erected. the 2 opposite sides of the tower section of the tower ar assembled on the bottom. every assembled aspect is then upraised beyond the bottom with the gin or derrick and is down into position on bolts to stubs or anchor bolts.

One aspect is h control in situ with props whereas the opposite aspect is being erected. the 2 opposite sides ar then laced beside cross members and diagonals; and also the assembled section is lined up, created sq. to the road. once finishing the primary section, gin pole is ready on the highest of the primary section. The gin rests on a strut of the tower like a shot below the leg joint. The gin pole then should be properly guyed into position.

The first face of the second section is raised. to lift the second face of this section it's necessary to slip the foot of the gin on the strut of the alternative face of the tower. once the 2 opposite faces are raised, the lacing on the opposite 2 sides is secured up. The last raise raise the highest of the tower. once the tower high is placed and every one aspect lacing are secured up all the guyed are thrown off except one that is employed to lower the gin pole. generally, whole one face of the tower is assembled on the bottom, hoisted and supported in position. the alternative face is equally assembled and hoisted and so the bracing angles connecting these 2 faces are fitted.

Ground Assembly technique of Tower Erection

This technique consists of grouping the tower on the ground, and erection it as an entire unit. the entire tower is assembled in an exceedingly horizontal position on the even ground. The tower is assembled on the direction of the road to permit the cross arms to be fitted. One slopping ground, however, elaborate packing of the low aspect is crucial before assembly commences. once the assembly is complete the tower is picked up from the bottom with the assistance of a crane and carried to its location, and assail its foundation. For this technique of erection, level piece of ground near footing is chosen from the tower assembly. This technique isn't helpful once the towers are massive and significant and also the foundations are placed in cultivable land wherever building and erection complete towers would cause injury to massive areas or in cragged parcel wherever the assembly of complete tower on sloping ground might not be doable and it's going to be tough to urge crane into position to lift the entire tower.

In India, this technique isn't usually adopted thanks to the preventive value of mobile crane, and non-availability of fine approach roads to tower locations.

Helicopter technique of Transmission Tower Erection

In the whirlybird technique, the transmission tower is erected in section. as an example, the bottom section is initially upraised on to the stubs and so the higher section is upraised and secured to the primary section and also the method is perennial until the entire tower is erected. generally, a very assembled tower is raised with the assistance of whirlybird. Helicopters {are also|also are|are} used for lifting fully assembled towers with guys from the marshalling yards wherever these are fancied and so transported one by one to line locations. whirlybird hovers over the road location whereas the tower is firmly guyed. the bottom crewmen connect and tighten the tower guys. As before long because the guy wires are adequately tensioned the whirlybird disengages and files to the marshalling yard. This technique is adopted wherever approach is v terribly tough or to hurry up the development of the line.

Tightening of barmy and Punching of Threads and Tack fastening of barmy of Transmission Towers

All barmy shall be tightened properly victimization correct sized spanners. Before alteration, it's ensured that filter washers and plates are placed in relevant gaps between members, a bolt of the correct size and length are inserted and one spring washer is inserted beneath e every nut. just in case of step bolts, spring washer shall be placed beneath the outer nut. The alteration shall be carried on more and more from the highest downward, care being taken each one} bolts at every level are tightened at the same time. it's going to be higher to use four persons, every covering one leg and also the face to his right.

The threads of bolts shall be projected outside the barmy by one to 2 threads and shall be punched at 3 positions on the highest inner outer boundary of the nut and bolt to make sure that the army doesn't seem to be disentangled in course of your time. If throughout alteration a nut is found to be slippy or running over the bolt threads, the bolt beside the nut shall be modified outright.

Painting of Joints of Transmission Tower

For galvanized towers is coastal or extremely impure areas, the joints shall be painted with Zn paint on all contact surfaces throughout the course of erection.

Checking the erectness of Erected Transmission Towers

The finally erected tower shall be actually vertical once erection and no straining is permissible to bring it into alignment. Tolerance limit for vertical shall be one in 360 of the tower height. SEO Services In Hyderabad