![]() The weight typically consists of several ounces of lead or iron encased in a hard material such as waxed wood or plastic. It consists of a weighted metal or lead object suspended from a string, cord, line or wire. How does plumb bob check verticality?Ī plumb bob is a simple device used to check verticality. In conclusion, a plumb bob is a simple and valuable device used in many instances where a spirit level may not be suitable, when a precise measurement of vertical is needed, or when an accurate vertical line is required. They can be easily stored when not being used and can be used repeatedly. Plumb bobs are also less expensive and are portable and easy to use. Plumb bobs can also be used when spirit levels are not accessible, when an exact measure of vertical is needed for a specific point, when the surface is not at an even level, or when measuring a vertical surface over a long distance. The bubble must be perfectly centered in the vial for it to be considered level. A spirit level has a vial with liquids inside, and a bubble is used to indicate level. They are used often in carpentry for measurements and alignments.Ī plumb bob is used instead of a spirit level (or bubble level) as it is more accurate and easier to use. ![]() It consists of a weight, usually metal, suspended from a string or cord. Optical plummet has an automatic compensator which increases its accuracy significantly compare with other methods used for controlling verticality.įig.A plumb bob is a device that uses gravity to determine if something is vertical or level. It is an instrument that sight directly down or directly up. These steps are illustrated in Figure 9.įig.6: Checking Verticality Using Theodoliteįig.7: Checking Column Verticality Using Theodolite 4. By taking two readings at the same level any curvature on the surface can be identified. Take the readings of two positions at the same level on both top and bottom levels of the formwork.Take the reading of the steel tape through the telescope.After Theodolite set up accurately the laser beam will be turned on and focused it to the steel tape which is held to the formwork.Setting up the digital Theodolite centered on a peg that installed 500 mm from the column grid.The procedure used to check column verticality includes: It is possible to measure the slope of out of plumb line of the member by using Theodolite in combination with a tape. It is suitable for checking or controlling verticality of towers as shown in Figure 8, wall, foundation and columns as shown in Figure 9 specifically large number of columns along a one grid line. Theodolite is substantially powerful instrument which can be used to check verticality works during construction with great precision and accuracy. ![]() If spirit level is employed for approximate checks, then it is required to check the verticality with more accurate technique. This tool is appropriate for controlling verticality of small scale works for example checking formworks and door frames. If the height of structural member is large, then it is possible to replace the string with a long wire, but substantial cautions should be plasticized so as to avoid imposing risks to the personals working below. Small to moderate lateral movement of plumb-bob can be reduced satisfactorily by damping it in oil or water. The plumb line or vertical line of plumb-bob is influenced by wind force and it will lose its accuracy and precision. ![]() Added to that, it is used to control verticality of foundation, walls, and columns.įig.3: Checking Verticality of Structural Elements This method is applied for checking or controlling vertical line of structural elements especially indoors such as lift shaft. The heavy weight will hang under gravity and offer a precise vertical line which is called plumb line. Plumb-bob as shown in Figure 2 consist of a weight with pointed tip on the bottom attached to end of a string. Methods used to check or control verticality works include: Various methods which to control or check verticality works during building construction are discussed.įig.1: Verticality Works During Building Construction Methods to Control Verticality of Structure during Building Construction □ Reading time: 1 minuteChecking verticality works would encounter during building construction at several stages such as during installing vertical formworks of columns and transferring levels up successive floors of multi storey structures.
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