single gantry tower | Gentry Tower Erection | Transmission line । Hazards & safety precautions
There are four main methods of the erection of steel transmission towers which are described below:
Build-up method or Piecemeal method.
Section method.
Ground assembly method.
Helicopter method.
Build Up Method of Transmission Tower Erection
This method is most commonly used in India for the erection of 6.6 kV, 132 kV, 220 kV, and 400 kV transmission line towers due to the following advantages :
Tower materials can be supplied to the site in a knocked down conditions which facilitates easier and cheaper transportation.
It does not require any heavy machinery such as cranes etc.
Tower erection activity can be done in any kind of terrain and mostly throughout the year.
Availability of workmen at cheap rates.
This method consists of erecting the towers, member by member. The tower members are kept on the ground serially according to the erection sequence to avoid search or time loss. The erection progresses from the bottom upwards.
The four main corner leg members of the first section of the tower are first erected and guard off. Sometimes more than one contiguous leg section of each corner leg is bolted together at the ground and erected.
The cross braces of the first section which are already assembled on the ground are raised one by one as a unit and bolted to the already erected corner leg angles. First section of the lower thus built and horizontal struts (belt members) if any, are bolted in position. For assembling the second section of the tower, two gin poles are placed one each on the top of diagonally opposite corner legs.
These two poles are used, for raising parts 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 top of the second section to raise the parts of the third section of the lower in position for assembly. Gin poles are thus moved up as the tower grows.
This process is continued until the complete tower is erected. Cross-arm members are assembled on the ground and raised up and fixed to the main body of the tower. For heavier towers, a small boom is rigged on one of the tower legs for hoisting purposes. The members/sections are hoisted either manually or by winch machines operated from the ground.
For smaller base towers/vertical configuration towers one gin pole is used instead of two gin poles. In order to maintain speed and efficiency, a small assembly party goes ahead of the main erection gang and its purpose is to sort out the tower members, keeping the member’s incorrect position on the ground and assembling the panels on the ground which can be erected as a complete unit.
Section Method of Transmission Tower Erection
In the section method, major sections of the tower are assembled on the ground and the same are erected as units. Either a mobile crane or a gin pole is used. The gin pole used is approximately 10 m long and is held in place by means of guys by the side of the tower to be erected
यहाँ स्टील ट्रांसमिशन टावरों के निर्माण की चार मुख्य विधियाँ हैं जिनका वर्णन नीचे किया गया है:
बिल्ड-अप विधि या टुकड़ा विधि।
खंड विधि।
ग्राउंड असेंबली विधि।
हेलीकाप्टर विधि।
ट्रांसमिशन टॉवर निर्माण की निर्माण विधिBuild
निम्नलिखित लाभों के कारण 6.6 केवी, 132 केवी, 220 केवी, और 400 केवी ट्रांसमिशन लाइन टावरों के निर्माण के लिए भारत में इस विधि का सबसे अधिक उपयोग किया जाता है:
टॉवर सामग्री को साइट पर एक खटखटाए गए परिस्थितियों में आपूर्ति की जा सकती है जो आसान और सस्ता परिवहन की सुविधा प्रदान करती है।
इसमें किसी भारी मशीनरी जैसे क्रेन आदि की आवश्यकता नहीं होती है।
टॉवर निर्माण गतिविधि किसी भी प्रकार के इलाके में और अधिकतर पूरे वर्ष में की जा सकती है।
सस्ते दरों पर कामगारों की उपलब्धता।
इस पद्धति में सदस्य द्वारा सदस्य, टावरों को खड़ा करना शामिल है। खोज या समय की हानि से बचने के लिए टावर के सदस्यों को इरेक्शन अनुक्रम के अनुसार क्रमिक रूप से जमीन पर रखा जाता है। इरेक्शन नीचे से ऊपर की ओर बढ़ता है।
टावर के पहले खंड के चार मुख्य कोने वाले सदस्यों को पहले खड़ा किया जाता है और गार्ड ऑफ किया जाता है। कभी-कभी प्रत्येक कोने के पैर के एक से अधिक सन्निहित लेग सेक्शन को जमीन पर एक साथ बोल्ट किया जाता है और खड़ा किया जाता