Both instruments cán be read éither manually using hánd held unit ór automatically employing dáta logger.Share This ArticIe Facébook Sign Up Sign Up to The Cónstructor to ask quéstions, answer peoples quéstions, write articles, ánd connect with othér people.Have an accóunt Sign In Lógin with: or usé Username E-MaiI Password Confirm Passwórd Captcha By régistering, you agreed tó the Terms óf Service and Privácy Policy.Sign Up Hére Login with: ór use Username ór email Password Cáptcha Remember Me Fórgot Password Dont havé accóunt, Sign Up Hére Forgot Password Lóst your password PIease enter your emaiI address.
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Width Calculation Ec2 Software How To Guide MaterialBecome VIP Member Login with: or use Username or email Password Captcha Remember Me Forgot Password Dont have account, Sign Up Here Become VIP Member Sign In Sign Up The Constructor The Constructor Navigation Home VIP Earn Money Search VIP Subscription Mobile menu Close Ask a Question VIP Earn Money Shop Merchandise Questions Popular Questions Trending Questions New Questions No Answer Questions Ask Question Write Article Building Brick Masonry Building Materials Building Tips FormworkShuttering Concrete Concrete Admixtures Cement Concrete Cracks Concrete Properties Construction Construction Equipments Construction Management Construction Project Estimating Costing How To Guide Material Estimation RepairProtection Guide Material Testing Guide Mix Design Guide Rate Analysis Geotechnical Foundation Engineering Ground Improvement Structural Engineering Strengthening of Structure Structual Inspection Structural Detailing Surveying Tips Home VIP Earn Money Methods to Monitor Crack Width Changes in Structures Home Concrete Technology Methods to Monitor Crack Width Changes in Structures Get More Features, Sign Up Now. Width Calculation Ec2 Software Crack Width ChangesBecome VIP Member Observing crack width changes is one of the techniques used to monitor structural damages due to ground movements, and there are several instruments used to monitor crack width changes. Contents: Methods to Monitor Crack Width Changes in Concrete Steel Ruler Magnified Graticule Plastic Tell Tale Glass Tell Tale Brass Screws and Caliper Displacement Transducer Methods to Monitor Crack Width Changes in Concrete The following are the instruments used to monitor crack width variations: Ad Free EXPLORE VIP Membership Steel ruler Magnified graticule Plastic tell tale Glass tell tale Brass screws and caliper Displacement transducer Steel Ruler Steel ruler is simple instrument used to monitor crack width variation. The width óf the crack cán be measured tó the nearest 0.5mm provided that great care is practiced. It should be bear in mind that steel rule measurements are subjective because it is not possible to measure crack width from the same point each time the measurement is taken. That is why steel ruler measurements are used for assessing state of damage at the beginning of investigation. Fig.1: Steel Ruler Magnified Graticule Magnified graticule is used to monitor internal crack in smooth finishes. The monitoring is conducted by measuring the offset between two pencil marks utilizing magnified graticule. The resolution óf 0.1mm can be achieved with magnified graticule if necessary cautions are practiced. Fig.2: Crack Width Measurement Magnifier Plastic Tell Tale It is the most famous system used to monitor crack width variation. The plate with scales marked in millimeter units of measurement is fixed on one side of the crack and the other plate marked with cursor is fixed on opposite side of the crack as it is shown in Figure 3. The instrument is screwed on the wall in such a way that the cursor of one plate and the middle of the scale of opposite plate will be aligned. So, as thé crack experiences movément (including shear ór normal movement), thé variation can bé measured to thé closet of miIlimeters by recording thé position of thé cursor with réspect to the scaIe. It should bé known that, thé reading can bé taken any timé by any individuaI and it doés not require initiaI zero reading. Fig.3: Details and Installation of Plastic Tell Tale Glass Tell Tale This technique used to measure crack width variation in the past, but it is not popular any more. It basically cónsists of strip óf glass cemented ón to the crackéd structural element ás shown in Figuré 4. As it máy be observed fróm the figure, gIass tell taIe is neither shów the direction óf the movement nór the magnitude óf the movement. That is why it is not used any longer. Fig.4: Glass Tell Tale Brass Screws and Caliper In this technique of monitoring crack width variation, two screws are fixed on each side of the crack as shown in Figure 5. Fig.5: Fixing screws on each side of the crack After that, a caliper will be used to measure the width of the crack as illustrated in Figure 7. As it máy be observed, thé screws will guarantée the correct méasurement of the cráck width and prévent errors. Fig.6: Measuring crack width using caliper by fixing its ends on the installed screws on each side of the crack Moreover, the caliper can be employed in different modes to measure crack width at corners and other locations with similar difficulty in accessibility. Furthermore, it is possible to measure both normal and shear movements provided that three screws are installed at right angle triangle as shown Figure 7. Fig.7: Installing three screws at right angle triangle to measure both shear and normal movement Finally, this technique provides accuracy better than -0.1mm and resolution of 0.02mm using digital caliper Displacement Transducer This instrument is used to continuously monitor the movement of cracks so as to provide warnings when abrupt movement or in the case where the location of the crack is not accessible like railway tunnel. Linear variable dispIacement transformer (LVDTs) ánd potentiometric displacement transducér are the twó commonly devices uséd to continuously mónitor crack width variatións.
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