These are painted with alternate bands of either red and white or black and white of 200 mm length such that at sometimes the rod can also be used for the rough measurement of short lengths. Ranging Rods are 30 mm in diameter and 2 or 3 m long. Ranging rods are required generally in cases where the length of chain or tape is small as compared to distance between the two stations. The process of locating a number of points on a long survey line is called Ranging or Ranging out. The length of the arrow varies from 250 mm to 500 mm. The arrow is pointed at one end and is provided with a loop at the other end. Generally 10 arrows are provided with a single chain. These arrows are made of hard tempered steel wire (minimum tensile strength of 700 N/mm²) of 4 mm diameter. The most common size of these pegs are 25 mm x 25 mm x 150 mm long, 40 mm x 40 mm x 400 mm long.Īrrows are used to mark the position of the end of the chain or tape on the ground. Pegs are generally made of wood (preferably hard timber) with square sections and tapers at one end. These pegs are also used to mark the intersection of lines and other such points which are more or less permanent. Pegs are used to mark the survey stations and end points of survey lines on the ground. It requires much attention in handling, hence not used for ordinary works.
They are made up of steel or stainless steel strips. As it is reinforced with brass or copper wires, all the defects of linen tapes are overcome. These are available in lengths of 20-30 m.It is an accurate measurement device and is commonly used for measuring offsets. The wires are not visible because it is varnished. This is a linen tape with brass or copper wires woven into it longitudinally to reduce stretching. It is likely to twist during measurement.It is affected by moisture and gets shrunk.These tapes are made of linen /cloth or synthetic material and are available in lengths of 10-30 m and widths of 12-15 mm.ĭisadvantages of Cloth or Linen Tape are: The different types of tapes used in general are discussed as below. Tapes are available in a variety of materials, lengths and weights. ⇒The overall length of the chain should be within the limits given below ⇒As per IS specifications, every metre length of the chain should individually be accurate to within ☒ mm when measured under a tension of 80 N (8 kgf). It is suitable for ordinary work only because the length of links gets altered by shortening/lengthening. As being heavier, it sags considerably when suspended in air.Ģ). The surveying chain is not as accurate as a steel tope or steel band. The various types of chains are as mentioned under below: A chain consists of a number of large links made of galvanised mild steel wire of 4mm diameter. But in addition to that, the following instruments and accessories are also required: (a) PegsĪ Surveying Chain, or simply a chain, is commonly used for measurement of distances where a very high accuracy is not required. In chain or tape surveying, obviously a tape or a chain is required. Instruments Used for Various Types of Measurement.Metric chain-30 m (150 links) or 20 m (100 links).Engineer’s chain – 100 ft long (100 links)= 30.48 meter.Revenue chain-33 ft long (16 links)= 10.06 meter.Unsteady Flow: Surge- Open Channel Flow (Chapter-6).Rapidly Varied Flow: Hydraulic Jump- Open Channel Flow (Chapter-5).Gradually Varied Flow- Open Channel Flow (Chapter-4).Energy Depth Relationship- Open Channel Flow (Chapter-3).Uniform Flow- Open Channel Flow (Chapter-2).Open Channel Flow – Introduction (Chapter-1).
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