ASTM C1197-2004 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 C1197-2004 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 C1197-2004 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 04Standard 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 (e) 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 u

3、nrein-forced solid-unit2masonry. This test method concerns themeasurement of in-situ masonry deformability properties inexisting masonry by use of thin, bladder-like flatjack devicesthat are installed in saw cut mortar joints in the masonry wall.This test method provides a relatively non-destructive

4、 means ofdetermining masonry properties.1.2 The values stated in inch-pound units are to be regardedas the standard. The values given in parentheses are forinformation only.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibili

5、ty of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:3E 74 Practice for Calibration of Force Measuring Instru-ments for Verifying the Load Indication of

6、Testing Ma-chines3. Summary of Test Method3.1 Two flatjacks inserted 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

7、 measuring the deformation of the ma-sonry between the flatjacks, 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

8、. Boundary effects of thecollar joint behind the wythe tested and 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 A flatjack

9、is a thin envelope-like bladder with inlet andoutlet ports which may 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 s

10、emi-rectangular as shown in Fig. 2.5.1.2 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 than the thicknessof one wythe and not less than

11、 3 in. (75 mm). The radius, R, forcircular and semi-rectangular flatjacks 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 t

12、o the expected maximum flatjackpressure.4Metal flatjacks suitable for this purpose shall be1This 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 January 1, 2004. Publi

13、shed February 2004. Originallyapproved in 1992. Last previous edition approved in 2003 as C 1197 - 03.2Solid-unit masonry is that built with stone, concrete, or clay units whose netarea is equal to or greater than 75 % of the gross area.3For referenced ASTM standards, visit the ASTM website, www.ast

14、m.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.4A maximum operating pressure of 1000 psi (6.9 MPa) is adequate for olderexisting masonry, but flatjacks with higher operati

15、ng pressures may be required formore recently constructed buildings. Flatjacks manufactured with flexible polymersthat have operating pressure ranges of less than 1000 psi (6.9 MPa) may be usefulfor stress measurements in some historic masonry.FIG. 1 Deformation Properties Using Two Flatjacks1*A Sum

16、mary 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.made of type 304 stainless steel sheet of 0.024 (0.6 mm) to0.048 in. (1.2 mm) in thickness with welded seams along theedges, a

17、nd incorporating hydraulic inlet or outlet ports.5.1.4 Calibrate all flatjacks as described in Section 7 todetermine their pressure-applied load characteristics.5.2 Hydraulic SystemAn electrically or manually oper-ated hydraulic pump with hydraulic hoses is required. Hoseconnections shall fit the fl

18、atjack inlet port. Measure pressureusing gages calibrated to a traceable standard having both anaccuracy of 1 % of full hydraulic scale and an appropriateoperating range. The hydraulic system shall be capable ofmaintaining constant pressure within 1 % of full scale for atleast 5 min.5.3 Displacement

19、 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 gage extensometer which measures the distancebetween fixed gage points on the

20、 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 gage length. Record measurements manually atdiscrete intervals, or continuously by auto

21、matic data recording.5.4 Attachment of Measurement DevicesAttach bracketsfor mounting electrical displacement measuring devices orgage points to be used with mechanical devices securely to thesurface of the masonry to prevent movement and ensure therequired measurement accuracy. Use rigid adhesive f

22、or discsand brackets and cementitious grout for plugs. If gage pointsare used, the gage points shall have a conical depression attheir center, compatible with the pointed elements of theextensometer. The angles of the depression of the cone and theextensometer points shall be the same.6. Preparation

23、 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 directly against the cleanedsurfaces of the masonry units.6.2 The plan geometry of th

24、e 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 by not more than 1.5 times the length of the flatjack.6.3 Prepare rec

25、tangular 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.6.4 Prepare slots for circular and

26、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 inherent stiffness which resists expan-sion when the jack is pressurized.

27、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 Calibrate flatjacks in a compression machine of at least100 kip (450 KN) ca

28、pacity which has been calibrated accord-ing to Practice E 74.7.3 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 flatjack beingcalibrated. Place the flatjack on the lower bearing plate

29、 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 113 times thecombined thickness of the two sheets used in fabrication

30、 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 that the centroid of the areaof the flatjack is within14 in. (6 mm)

31、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 full contact between the bearing plates andthe spacers, equivalent t

32、o 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 controllablemachine. If not, attach displacement gages (mechanical orelectrical

33、) such that the distance between platens established bythe procedures of paragraph 7.4 can be held constant whenusing a force-control test machine.7.6 Pressurize and depressurize the flatjack three times overthe full operating pressure range. Do not exceed the maximumflatjack operating pressure.7.6.

34、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 at least 10 equal increments between 0 psi and themaximum flatjack operating pressure. At each increment,record flat

35、jack hydraulic pressure and force applied by the testmachine.FIG. 2 Flatjack ConfigurationsC11970427.7 Calculate the load applied by the flatjack as internalpressure times gross flatjack area. Plot flatjack load versus loadmeasured by the test machine with the flatjack load on thehorizontal axis of

36、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 location where masonry deformability estimates areconducted is dictated by en

37、gineering 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 of slots to be formed.8.3 Prepare the slots5(see Section 6) and record the m

38、ea-sured slot dimensions. Clean slots of all mortar and brickparticles 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 the flatjack.8.4 Attach at least four equally spaced pairs of gage pointsor electrical mea

39、suring device mounting brackets on the centerof the course immediately below the upper slot location and onthe center of the course immediately above the lower slotlocation as shown in Fig. 1. The first and last measurementpoints should be located at least a distance A/8 in from the endsof the slot,

40、 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 flatjacks untilp

41、ressure 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 Take initial me

42、asurements 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 pressure is steady

43、 at each incremental step, andrecord displacements (three repetitions at each gage 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 not desired,

44、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 also cause dama

45、ge 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 mortar.9. Calc

46、ulation9.1 Calculate stress in the masonry between the flatjacks atany point in the pressurization process as:fm5 KmKap (2)where:5The location of the slots shall be at least 112 flatjack lengths from wall openingsor ends. There should be sufficient masonry above the top slot to resist forcesdevelope

47、d during pressurization of the flatjacks.FIG. 3 Flatjack Calibration SetupC1197043Km= a dimensionless constant which reflects the geometri-cal and stiffness properties of the flatjack, as deter-mined by the calibration procedure in Section 7,Ka= the ratio of measured area of the flatjack to theavera

48、ge 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 gage length.Calculate the average strain value for each load increment asthe average of the individual strains recorded at ea

49、ch measure-ment location.9.3 Calculate the tangent modulus at any stress interval by:Et5dfmdem(3)where:dfm= an increment of stress, psi or MPa, anddem= the corresponding increment of strain.The chord modulus at any point, i, is given by:Esi5fmiemi(4)where:fmi= stress at point i, andemi= strain at point i.10. Report10.1 A report of each in situ deformation property measure-ment should include at least the following information:10.2 Description of the test conditions, for example, site,geographical location, environmental conditions (for example,temperature), building identificat