Surveying Module 1 - Distance Measuring

Chaining Equipment

• Hundred foot steel tape

• Chain pins standard set of 11 pins

• Wooden steaks

• Hand level

• Range poles

• Plum bobs

Chaining on level ground - 6 Steps

• Lining in

• Applying tension

• Measuring horizontally

• Marking tape lengths

• Reading the tape

• Recording the distance

Training on level ground - lining in

The shortest distance between two points is a straight line

Mark Beginning and end points using range poles

Mark intermediate points if necessary

Maintain proper alignment

Chaining on level ground - Applying tension

Chain must be pulled tight to achieve the precision expected

Exact tension varies with chain being used

Typical chain used in construction 20 to 25 pounds of tension

Remember to pull hard

chaining on level ground - Measuring horizontally

Distance shown on plan view of plans are horizontal unless noted otherwise

When chaining distances shall be laid out horizontally

Use a slight level to determine where horizontal is

Use the plumb bob to plum down to the point

Chaining on level ground - Marking tape lengths

Rear chain - when the end of the chain is over the point, resist the tension being applied and yells good or Mark

Head chain - applies tension identifies the spot on the ground that marks the end of the chain and places chaining pin

Chaining on level ground - Reading the tape

possibly the greatest source of error in training is that the users are not familiar with the chain where is zero?

Always examine a chain closely before using it

Forget about reading feet and inches the engineering chain is graduated in feet 10 and hundreds

Chaining on Level Ground - Recording the distance

Accurate fieldwork may be cancelled by a careless recording

After the partial length is obtained at the end of a line, determine the number of full 100 feet tap lengths by counting the pins collected

Measure all distances twice forward and back

Mistakes and Errors in Chaining

Common mistakes

Chain not horizontal

Reading the tape incorrectly

Miscounting the number of full tape length

Transposing figures

Measuring conditions

• Measuring a distance refers to checking the distance of two points already existing in the ground

• Laying out refers to setting points at a prescribed distance taken from the plans or from calculations

Distance corrections chain corrections for length

Distance corrections, slope corrections

Slope correction formula

Chain correction for slope

Chain correction for temperature