ASTM C1196-2014a Standard Test Method for In Situ Compressive Stress Within Solid Unit Masonry Estimated Using Flatjack Measurements《用液压千斤顶现场测量估计实心砌块抗压应力的标准试验方法》.pdf

《ASTM C1196-2014a Standard Test Method for In Situ Compressive Stress Within Solid Unit Masonry Estimated Using Flatjack Measurements《用液压千斤顶现场测量估计实心砌块抗压应力的标准试验方法》.pdf》由会员分享，可在线阅读，更多相关《ASTM C1196-2014a Standard Test Method for In Situ Compressive Stress Within Solid Unit Masonry Estimated Using Flatjack Measurements《用液压千斤顶现场测量估计实心砌块抗压应力的标准试验方法》.pdf（6页珍藏版）》请在麦多课文档分享上搜索。

1、Designation: C1196 14aStandard Test Method forIn Situ Compressive Stress Within Solid Unit MasonryEstimated Using Flatjack Measurements1This standard is issued under the fixed designation C1196; the number immediately following the designation indicates the year oforiginal adoption or, in the case o

2、f revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This test method covers the determination of the averagecompressive stress in existing unrein

3、forced solid-unit masonry(see Note 1). This test method concerns the measurement ofin-situ compressive stress in existing masonry by use of thin,bladder-like flatjack devices that are installed in cut mortarjoints in the masonry wall. This test method provides arelatively non-destructive means of de

4、termining masonry prop-erties in place.NOTE 1Solid-unit masonry is that built with stone, concrete, or clayunits whose net area is equal to or greater than 75 % of the gross area.1.2 The values stated in inch-pound units are to be regardedas standard. The values given in parentheses are mathematical

5、conversions to SI units that are provided for information onlyand are not considered standard.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health pra

6、ctices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2C1180 Terminology of Mortar and Grout for Unit MasonryC1232 Terminology of MasonryE74 Practice of Calibration of Force-Measuring Instrumentsfor Verifying the Force Indication of

7、Testing Machines3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 shim, nitem inserted into a flatjack slot prior totesting to minimize the inflation of the test flatjack.3.1.1.1 DiscussionThe use of shims may be necessaryduring testing to achieve a tight fit of the flatjack in

8、the slot andto ensure uniform transfer of pressure (stress) to the masonryover the complete area of the flatjack. SeeAnnexA1 for furtherdiscussion on allowable types of shims.3.1.2 spacermetal plate used in the calibration process tocontrol flatjack thickness.3.2 For definitions of other terms used

9、in this test methodrefer to Terminology C1180 for mortar and grout and Termi-nology C1232 for masonry.4. Summary of Test Method4.1 When a slot is formed in the masonry, compressivestress at that point will cause the masonry above and below theslot to move together. Compressive stress in the masonry

10、maybe measured by inserting a flatjack into the slot and increasingits internal pressure until the original distance between pointsabove and below the slot is restored. The state of compressivestress in the masonry is approximately equal to the flatjackpressure multiplied by factors which account fo

11、r the physicalcharacteristics of the jack and the ratio of (a) the bearing areaof the jack in contact with the masonry to (b) the bearing areaof the slot.5. Significance and Use5.1 Stress is applied as pressure over the area of the flatjack.In the case of multi-wythe masonry, stress is estimated onl

12、y inthe wythe in which the flatjack is inserted. Stress in otherwythes may be different.6. Apparatus6.1 Flatjack:6.1.1 Aflatjack is a thin envelope-like bladder with inlet andoutlet ports which may be pressurized with hydraulic fluid.Flatjacks may be of any shape in plan, and are designed to becompa

13、tible with the masonry being tested. Typical configura-tions are shown in Fig. 1.6.1.2 For determination of the state of compressive stress,dimension A should be equal to or greater than the length of asingle masonry unit, but not less than 8 in. (200 mm).Dimension B should be equal to or greater th

14、an the thicknessof one wythe and not less than 3 in. (75 mm). The radius, R, for1This test method is under the jurisdiction of ASTM Committee C15 onManufactured Masonry Units and is the direct responsibility of SubcommitteeC15.04 on Research.Current edition approved Dec. 1, 2014. Published December

15、2014. Originallyapproved in 1992. Last previous edition approved in 2014 as C1196 14. DOI:10.1520/C1196-14A.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the stan

16、dards Document Summary page onthe ASTM website.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1circular and semi-rectangular flatjacks shall be equal to theradius of the

17、 circular saw blade used to cut the slot.6.1.3 Flatjacks shall be made of metal or other material suchthat the flatjack in a slot in masonry will be capable of applyingoperating pressures up to the expected maximum flatjackpressure. See Note 2. Metal flatjacks suitable for this purposeshall be made

18、of type 304 stainless steel sheet of 0.024 in.(0.6 mm) to 0.048 in. (1.2 mm) in thickness with welded seamsalong the edges and incorporating hydraulic inlet or outletports.NOTE 2A maximum operating pressure of 1000 psi (6.9 MPa) or lessis often adequate for older existing masonry, but flatjacks with

19、 higheroperating pressures may be required for more recently constructedbuildings. Flatjacks manufactured with flexible polymers that have oper-ating pressure ranges of less than 1000 psi (6.9 MPa) may be useful forstress measurements in some historic masonry.6.1.4 Calibrate all flatjacks as describ

20、ed in Section 8 todetermine their pressure-applied load characteristics.6.2 Hydraulic SystemA hydraulic pump with hydraulichoses is required. Hose connections shall fit the flatjack inletport. Measure pressure using gages calibrated to a traceablestandard having both an accuracy of 1 % of full hydra

21、ulic scaleand an appropriate operating range. The hydraulic system shallbe capable of maintaining constant pressure within 1 % of fullscale for at least 5 min.6.3 Displacement MeasurementMeasure displacements ofthe masonry by a mechanical gage extensometer which mea-sures the distance between fixed

22、gage points on the masonry asshown in Fig. 2. The method or device used to measuredeformations shall be capable of deformation measurements upto316 in. (5 mm). Deformation measurements shall have anaccuracy of at least 60.005 % of gage length.6.4 Gage PointsUse adhered metal discs or embeddedmetal i

23、nserts as gage points during the measurement process.Attach gage points securely to the masonry (using a rigidadhesive for discs or cementitious grout for plugs) which willprevent movement and ensure the required measurement accu-racy. The gage points shall have a conical depression at theircenter,

24、compatible with the pointed elements of the extensom-eter. The angles of the depression of the cone and theextensometer points shall be the same.7. Preparation of Slots7.1 Slots in masonry are normally prepared by removing themortar from masonry bed joints to avoid disfiguring themasonry. Remove all

25、 mortar in the bed joint, so that pressureexerted by a flatjack shall be directly against the surfaces of themasonry units.7.2 The plan geometry of the slot shall be similar to that ofthe flatjack being used. Plan dimensions of the prepared slotshall not exceed those of the flatjack by more than12 i

26、n. (12mm).7.3 Prepare rectangular slots into which rectangular flat-jacks are to be inserted by drilling adjacent or overlappingholes (stitch drilling) and subsequently using a drill, bar, or toolto remove mortar and produce a slot of desired dimensionswith smooth upper and lower surfaces. Other too

27、ls, such asoscillating blade grinders that can be reliably used to formrectangular slots in masonry mortar joints without damagingthe surrounding masonry, are also permitted to be used.7.4 Prepare slots for circular and semi-rectangular flatjacksusing circular saws of sufficient radius to provide th

28、e depthrequired (Fig. 1, dimension B). Use carbide or diamond tippedblades to remove all mortar from the slot.8. Calibration8.1 A flatjack has an inherent stiffness which resists expan-sion when the jack is pressurized. Therefore, the fluid pressurein the flatjack is greater than the stress the flat

29、jack applies tomasonry. A flatjack must be calibrated to provide a conversionfactor, Km, to relate internal fluid pressure to stress applied.8.2 Calibrate flatjacks in a compression machine of at least100 kip (450 KN) capacity which has been calibrated accord-ing to Practice E74.8.3 Place a 2 in. (5

30、0 mm) thick steel bearing plate on thelower platen of the compression machine. The bearing plateshall be of sufficient size to completely cover the flatjack beingcalibrated. Place the flatjack on the lower bearing plate suchFIG. 1 Flatjack Configurations (Plan View)FIG. 2 Flatjack Test Setup for In

31、Situ Stress MeasurementC1196 14a2that the edge of the flatjack with the inlet/outlet ports iscoincident with the edge of the bearing plate. Place steelspacers around the other edges of the flatjack. The thickness ofthe spacers shall be 0.015 to 0.050 in. (0.38 to 1.27 mm)greater than the sum of the

32、combined thickness of the twosheets plus the thickness of inlet/outlet port used in fabricationof the flatjack. Place the upper 2 in. (50 mm) thick bearingplate on top of the spacers and flatjack, and align it to bedirectly above the lower bearing plate. Position the bearingplate/flatjack/spacer ass

33、embly on the lower platen such that thecentroid of the area of the flatjack is within14 in. (6 mm) of theaxis of thrust of the test machine. The calibration setup isillustrated in Fig. 3.8.4 Raise or lower the moveable platen such that bothplatens are in contact with the bearing plates. Apply a pre-

34、loadsufficient to provide full contact between the bearing plates andthe spacers, equivalent to 10 psi (0.07 MPa) over the gross areaof the flatjack.8.5 The distance between platens must be held constantduring the calibration procedure. Fix the displacement of thetest machine at this point if using

35、a displacement-controlmachine. If not, attach displacement gages (mechanical orelectrical) such that the distance between platens established bythe procedures of paragraph 8.4 can be held constant whenusing a force-control test machine.8.6 Pressurize and depressurize the flatjack three times overthe

36、 full operating pressure range. Do not exceed the maximumflatjack operating pressure.8.6.1 While holding the distance between the platensconstant, increase the pressure in the flatjack in equal incre-ments to within 5 percent of the maximum flatjack operatingpressure. Use at least 10 equal increment

37、s between 0 psi andthe maximum flatjack operating pressure. At each increment,record flatjack hydraulic pressure and force applied by the testmachine.8.7 Calculate the load applied by the flatjack as internalpressure times gross flatjack area. Plot flatjack load versus loadmeasured by the test machi

38、ne with the flatjack load on thehorizontal axis of the plot. The slope of the line is equal to theflatjack constant, that is, the conversion factor:Km5 PmachinePflatjack(1)8.8 Recalibrate flatjacks after using five times or whendistortion appears excessive.9. Procedure9.1 The location at which compr

39、essive stress estimates areperformed is dictated by engineering objectives. The basicarrangement is illustrated in Fig. 2. At the desired location orlocations the following steps should be taken:9.2 Select and mark a visible line on the masonry to definethe location and length of slots to be formed.

40、9.3 Attach at least four pairs of equally spaced gage discs orembedded plugs vertically aligned above and below the slot asshown in Fig. 2. Each row of gage points thus formed shall beequally spaced above and below the flatjack. The minimumgage length shall be 0.3 times the length, A, where A is the

41、length of the flatjack as shown in Fig. 1. The maximum gagelength shall be 0.6 times the length, A, of the flatjack. The firstand last locations shall be located not less than18 of dimensionAinward toward the center of the slot from each end, as shownin Fig. 2.NOTE 3Alternative instrumentation confi

42、gurations are acceptable ifcontrolled laboratory tests are conducted to verify the validity of thealternate instrumentation approach. Examples of alternate configurationsare shown in Fig. 4. These references provide additional information aboutalternate instrumentation for flatjack testing.3-53Ronca

43、, P., “The Significance of the Gauging System in the Flatjack In-SituStress Test for Masonry: Experimental Investigation,” The Masonry SocietyJournal, Vol 14, No. 1, August 1996.FIG. 3 Flatjack Calibration Setup (Elevation View)C1196 14a39.4 Measure the initial distance between each pair of gagepoin

44、ts.9.5 Prepare the slot (see Note 4) (see Section 7) and recordthe measured slot dimensions and the time. Clean slots of allmortar and brick particles prior to the insertion of flatjacks.NOTE 4The location of the slot shall be at least 112 flatjack lengthsfrom wall openings or ends.9.6 Repeat step 9

45、.4 after the slot has been prepared to obtainthe initial deviation from the original gage distances.9.7 Insert the flatjack into the slot. Shim as required toachieve a tight fit and bridge over any interior voids in themasonry. See the Annex for a description of flatjack shims andtheir use.9.8 Conne

46、ct hydraulic hoses and fill the calibrated flatjackwith hydraulic fluid until pressure begins to develop.9.9 In order to seat the flatjack and any shims, pressurize theflatjack to approximately 50 % of the estimated maximumflatjack pressure (which corresponds to the estimated compres-sive stress in

47、the masonry). Reduce the flatjack pressure tozero.9.10 Increase pressure in the flatjack to 25 %, 50 %, and75 % of the estimated maximum pressure holding the pressuresteady at each level.At each increment, measure and record thedistance between each pair of gage points. Three repetitions ofdisplacem

48、ent measurement are required at each gage point. It isrecommended that the test be conducted as soon as possibleafter formation of the slot: the time taken for load applicationshall be approximately equal to the time elapsed since forma-tion of the slot to minimize the effects of creep deformations.

49、9.11 Continue pressurizing until the original gage distancesare restored. The allowable average deviation from the originalgage length shall be the greater of 60.0005 in. (60.013 mm)or120 th of the maximum initial deviation, with no singledeviation exceeding the greater of 60.001 in. (60.025 mm) or110 th of the maximum deviation. Tests in which these limitsare exceeded shall be considered invalid. Record the finalflatjack pressure.9.12 Reduce the flatjack pressure to zero.9.13 A second repetition of 9.10 and 9.11 is recommendedto verify the final flatjack pressur