ASTM C1197-2009 Standard Test Method for In Situ Measurement of Masonry Deformability Properties Using the Flatjack Method《用液压千斤顶法现场测量砖石建筑可变形性的标准试验方法》.pdf

《ASTM C1197-2009 Standard Test Method for In Situ Measurement of Masonry Deformability Properties Using the Flatjack Method《用液压千斤顶法现场测量砖石建筑可变形性的标准试验方法》.pdf》由会员分享，可在线阅读，更多相关《ASTM C1197-2009 Standard Test Method for In Situ Measurement of Masonry Deformability Properties Using the Flatjack Method《用液压千斤顶法现场测量砖石建筑可变形性的标准试验方法》.pdf（5页珍藏版）》请在麦多课文档分享上搜索。

1、Designation: C 1197 09Standard Test Method forIn Situ Measurement of Masonry Deformability PropertiesUsing the Flatjack Method1This standard is issued under the fixed designation C 1197; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revisi

2、on, 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 describes an in situ method fordetermining the deformation properties of existing un

3、rein-forced solid-unit masonry. (See Note 1.) This test methodconcerns the measurement of in-situ masonry deformabilityproperties in existing masonry by use of thin, bladder-likeflatjack devices that are installed in saw cut mortar joints in themasonry wall. This test method provides a relatively no

4、n-destructive means of determining masonry properties.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 a

5、re mathematicalconversions 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

6、 and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2E74 Practice of Calibration of Force-Measuring Instru-ments for Verifying the Force Indication of Testing Ma-chines3. Summary of Test Method3.1 Two flatjacks inser

7、ted into parallel slots, one above theother, in a solid-unit masonry wall are pressurized thusinducing compressive stress on the masonry between them.The installation is shown in Fig. 1. By gradually increasing theflatjack pressure and measuring the deformation of the ma-sonry between the flatjacks,

8、 load-deformation (stress-strain)properties may be obtained. Maximum compressive strengthsmay be measured in certain cases.4. Significance and Use4.1 Deformation and strength properties are measured onlyon the masonry between flatjacks. Boundary effects of thecollar joint behind the wythe tested and

9、 adjacent masonry areneglected. In the case of multi-wythe masonry, deformability isestimated only in the wythe in which the flatjack is inserted.Deformability of other wythes may be different.5. Apparatus5.1 Flatjack:5.1.1 Aflatjack is a thin envelope-like bladder with inlet andoutlet ports which m

10、ay be pressurized with hydraulic oil.Flatjacks may be of any shape in plan, and are designed to becompatible with the masonry being tested. For determiningload-deformation properties of masonry, flatjacks are typicallyrectangular or semi-rectangular as shown in Fig. 2.5.1.2 For determination of the

11、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 than the thicknessof one wythe and not less than 3 in. (75 mm). The radius, R, forcircular and semi-rectangular fl

12、atjacks shall be equal to theradius of the circular saw blade used to cut the slot.5.1.3 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 flatjac

13、ks suitable for this purpose1This 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 June 1, 2009. Published July 2009. Originally approvedin 1992. Last previous edition

14、approved in 2004 as C 1197 04.2For 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 standards Document Summary page onthe ASTM website.FIG. 1 Deformation Properties U

15、sing Two Flatjacks1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.shall be made of type 304 stainless steel sheet of 0.024 (0.6mm) to 0.048 in. (1.2 mm) in thickness w

16、ith welded seamsalong the edges, and incorporating hydraulic inlet or outletports.NOTE 2A maximum operating pressure of 1000 psi (6.9 MPa) isadequate for older existing masonry, but flatjacks with higher operatingpressures may be required for more recently constructed buildings.Flatjacks manufacture

17、d with flexible polymers that have operating pres-sure ranges of less than 1000 psi (6.9 MPa) may be useful for stressmeasurements in some historic masonry.5.1.4 Calibrate all flatjacks as described in Section 7 todetermine their pressure-applied load characteristics.5.2 Hydraulic SystemA hydraulic

18、pump with hydraulichoses is required. Hose connections shall fit the flatjack inletport. Measure pressure using gauges calibrated to a traceablestandard having both an accuracy of 1 % of full hydraulic scaleand an appropriate operating range. The hydraulic system shallbe capable of maintaining const

19、ant pressure within 1 % of fullscale for at least 5 min.5.3 Displacement MeasurementMeasure displacementsof the masonry with electronic instrumentation, for example, aLinearly Variable Differential Transformer (LVDT) mounted tothe surface of the masonry between the flatjacks, or by amechanical gauge

20、 extensometer which measures the distancebetween fixed gauge points on the masonry as shown in Fig. 1.The method or device used to measure deformations shall becapable of deformation measurements up to316 in. (5 mm).Deformation measurements shall have an accuracy of at least60.005 % of gauge length.

21、 Record measurements manually atdiscrete intervals, or continuously by automatic data recording.5.4 Attachment of Measurement DevicesAttach bracketsfor mounting electrical displacement measuring devices orgauge points to be used with mechanical devices securely tothe surface of the masonry to preven

22、t movement and ensure therequired measurement accuracy. Use rigid adhesive for discsand brackets and cementitious grout for plugs. If gauge pointsare used, the gauge points shall have a conical depression attheir center, compatible with the pointed elements of theextensometer. The angles of the depr

23、ession of the cone and theextensometer points shall be the same.6. Preparation of Slots6.1 Slots in masonry are normally prepared by removing themortar from masonry bed joints to avoid disfiguring themasonry. Remove all mortar in the bed joint, that is, pressureexerted by a flatjack shall be directl

24、y against the surfaces of themasonry units.6.2 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 in. (12mm). Slots shall be parallel and aligned vertically, and shall beseparated

25、 by not more than 1.5 times the length of the flatjack.6.3 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 dimensionswi

26、th smooth upper and lower surfaces.6.4 Prepare slots for circular and semi-rectangular flatjacksusing circular saws of sufficient radius to provide the depthrequired (Fig. 2, dimension B). Use carbide or diamond tippedblades to remove all mortar from the slot.7. Calibration7.1 A flatjack has an inhe

27、rent stiffness which resists expan-sion when the jack is pressurized. Therefore, the fluid pressurein the flatjack is greater than the stress the flatjack applies tomasonry. A flatjack must be calibrated to provide a conversionfactor, Km, to relate internal fluid pressure to applied stress.7.2 Calib

28、rate flatjacks in a compression machine of at least100 kip (450 KN) capacity which has been calibrated accord-ing to Practice E74.7.3 Place a 2 in. (50 mm) thick steel bearing plate on thelower platen of the compression machine. The bearing plateshall be of sufficient size to completely cover the fl

29、atjack beingcalibrated. Place the flatjack on the lower bearing plate suchthat 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 equal to approximately

30、113 times thecombined thickness of the two sheets used in fabrication of theflatjack. Place the upper 2 in. (50 mm) thick bearing plate ontop of the shims and flatjack, and align it to be directly abovethe lower bearing plate. Position the bearing plate/flatjack/shimassembly on the lower platen such

31、 that the centroid of the areaof the flatjack is within14 in. (6 mm) of the axis of thrust of thetest machine. The calibration setup is illustrated in Fig. 3.7.4 Raise the moveable platen such that the non-moveableplaten is in contact with the top bearing plate. Apply a pre-loadsufficient to provide

32、 full contact between the bearing plates andthe spacers, equivalent to 10 psi (0.07 MPa) over the gross areaof the flatjack.7.5 The distance between platens must be held constantduring the calibration procedure. Fix the displacement of thetest machine at this point if using a displacement-controlmac

33、hine. If not, attach displacement gauges (mechanical orelectrical) such that the distance between platens established bythe procedures of paragraph 7.4 can be held constant whenusing a force-control test machine.FIG. 2 Flatjack Configurations (Plan View)C11970927.6 Pressurize and depressurize the fl

34、atjack three times overthe full operating pressure range. Do not exceed the maximumflatjack operating pressure.7.6.1 While holding the distance between the platens con-stant, increase the pressure in the flatjack in equal incrementsto within 5 percent of the maximum flatjack operating pressure.Use a

35、t least 10 equal increments between 0 psi and themaximum flatjack operating pressure. At each increment,record flatjack hydraulic pressure and force applied by the testmachine.7.7 Calculate the load applied by the flatjack as internalpressure times gross flatjack area. Plot flatjack load versus load

36、measured by the test machine with the flatjack load on thehorizontal axis of the plot. The slope of the line equals theflatjack constant, that is, the conversion factor:Km5 Pmachine4 Pflatjack(1)7.8 Recalibrate flatjacks after using five times or whendistortion appears excessive.8. Procedure8.1 The

37、location where masonry deformability estimates areconducted is dictated by engineering objectives. The basicarrangement is illustrated in Fig. 1. At the desired location orlocations the following steps should be taken.8.2 Select and mark a visible line on the masonry to definethe location and length

38、 of slots to be formed.8.3 Prepare the slots (see Note 3) (see Section 6) and recordthe measured slot dimensions. Clean slots of all mortar andbrick particles prior to the insertion of flatjacks. Slots shall beseparated by at least five courses of masonry, but not more than1.5 times the length of th

39、e flatjack.NOTE 3The location of the slots shall be at least 112 flatjack lengthsfrom wall openings or ends. There should be sufficient masonry above thetop slot to resist forces developed during pressurization of the flatjacks.8.4 Attach at least three equally spaced pairs of gauge pointsor electri

40、cal measuring devices as shown in Fig. 1. Centermeasurement points vertically between flatjacks, with a mini-mum gauge length of 8 in. Locate the measurement points onmasonry units, not at mortar joints. The first and last measure-ment points should be located at least a distance A/8 in from theends

41、 of the slot, where A is the flatjack length as shown in Fig.2.8.5 Insert the flatjack into the slot. Shim, as required, toachieve a tight fit and bridge over any interior voids in themasonry. See Annex A1 for a description of flatjack shims andtheir use.8.6 Connect hydraulic hoses and fill the flat

42、jacks untilpressure begins to develop.8.7 In order to seat the flatjack and any shims, pressurize theflatjack to approximately 50 % of the estimated maximumflatjack pressure (which corresponds to the estimated maxi-mum compressive strength of the masonry). Reduce theflatjack pressure to zero.8.8 Tak

43、e initial measurements with mechanical devices(three repetitions) or initialize electrical devices.8.9 Increase pressure slowly. Take displacement measure-ments at small increments of pressure. If measurements are tobe taken manually, stop and hold the pressure for at least oneminute or until pressu

44、re is steady at each incremental step, andrecord displacements (three repetitions at each gauge point inthe case of mechanical measurement devices). Monitor theflatjack pressure-masonry deformation ratio, p, during the testat each increment of pressure. If failure of the masonrybetween flatjacks is

45、not desired, the test should stop when theabove ratio begins to noticeably decrease.8.10 In older masonry or masonry of low-strength units andlow or zero cement content mortar, flatjacks are capable ofloading the masonry between them to failure thus establishingmaximum strength. However, this may al

46、so cause damage tothe masonry in areas adjacent to the flatjacks.8.11 Release pressure after the final displacement measure-ment has been taken.8.12 Disconnect hoses and remove the flatjack. The slotmay be filled with mortar or other suitable material of a colorand strength similar to the original m

47、ortar.FIG. 3 Flatjack Calibration Setup (Elevation View)C11970939. Calculation9.1 Calculate stress in the masonry between the flatjacks atany point in the pressurization process as:fm5 KmKap (2)where:Km= a dimensionless constant which reflects the geometri-cal and stiffness properties of the flatjac

48、k, as deter-mined by the calibration procedure in Section 7,Ka= the ratio of measured area of the flatjack to theaverage measured area of the slot, andp = flatjack pressure, psi or MPa.9.2 Calculate individual strain values by dividing the dis-placement recorded at each load increment by the gaugele

49、ngth. Calculate the average strain value for each loadincrement as the average of the individual strains recorded ateach measurement location.9.3 Calculate the tangent modulus at any stress interval by:Et5dfmdm(3)where:dfm= an increment of stress, psi or MPa, anddm= the corresponding increment of strain.The chord modulus at any point, i, is given by:Esi5fmimi(4)where:fmi= stress at point i, andmi= strain at point i.10. Report10.1 A report of each in situ deformation property measure-ment shall include the following information:10.1.1 Description of the test conditions