1、Designation: C 1531 03Standard Test Methods forIn Situ Measurement Of Masonry Mortar Joint ShearStrength Index1This standard is issued under the fixed designation C 1531; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of
2、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 These test methods cover procedures for the determina-tion of the average in situ mortar joint shear strength index
3、inexisting unreinforced solid-unit and ungrouted hollow-unitmasonry built with clay or concrete units. Three methods areprovided:1.1.1 Method A (with Flatjacks Controlling Normal Com-pressive Stress)For determining mortar joint shear strengthindex when the state of normal compressive stress at the t
4、estsite is controlled during the test using the flatjack methoddescribed in Test Method C 1197. Horizontal displacement ofthe test unit is monitored throughout the test. The test setup forMethod A is shown in Fig. 1.1.1.2 Method B (without Flatjacks Controlling NormalCompressive Stress)For determini
5、ng mortar joint shearstrength index when using an estimate of the normal compres-sive stress at the location of the test site. Horizontal displace-ment of the test unit is not monitored during this procedure.The test set up for Method B is shown in Fig. 2.1.1.3 Method C (with Flatjack Applying Horiz
6、ontal Load)For determining mortar joint shear strength index using anestimate of the normal compressive stress at the location of thetest site, as shown in Fig. 3. Horizontal displacement of the testunit is generally not measured during this procedure.1.2 The values stated in inch-pound units are to
7、 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 theresponsibility of the user of this standard to establish appro-priate safety and health practices an
8、d determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:C 43 Terminology of Structural Clay Products2C 1180 Terminology of Mortar and Grout for Unit Ma-sonry2C 1196 Test Method for In Situ Compressive Stress WithinSolid Unit Masonry Estimated U
9、sing Flatjack Measure-ments2C 1197 Test Method for In Situ Measurement of MasonryDeformability Properties Using the Flatjack Method2C 1209 Terminology of Concrete Masonry Units and Re-lated Units2C 1232 Terminology of Masonry2E 4 Practices for Force Verification of Testing Machines32.2 Other Documen
10、t:Uniform Code for Building Conservation (Appendix Chap-ter 1, Earthquake Hazard Reduction in Existing Unrein-forced Masonry Buildings), International Conference ofBuilding Officials, Whittier, CA, 19973. Terminology3.1 Terminology defined in Terminologies C 43, C 1180,C 1209, and C 1232 shall apply
11、 for these test methods.4. Summary of Test Method4.1 The in-place shear test is used to provide an index of thein situ, horizontal shear resistance of mortar joints in unrein-forced masonry. For Method A, a single masonry unit isremoved from opposite ends of the chosen test unit as shownin Fig. 1. F
12、or Method B, a single masonry unit and a head jointare removed from opposite ends of the chosen test unit, asshown in Fig. 2. For Method C, head joints on both ends of thetested unit are removed as shown in Fig. 3. Ensure that the bedjoints are not disturbed in the unit to be tested. The test unit i
13、sthen displaced horizontally relative to the surrounding masonryusing a hydraulic jack or specialized flatjacks. The horizontalforce required to cause first movement of the test unit providesa measured index of the mortar joint shear strength.5. Significance and Use5.1 The masonry mortar joint shear
14、 strength index obtainedby this test method is related to the masonry wall shear strengthby a relationship contained within Appendix Chapter 1 of theUniform Code for Building Conservation. The user of this1These test methods are under the jurisdiction of ASTM Committee C15 onManufactured Masonry Uni
15、ts and are the direct responsibility of SubcommitteeC15.04 on Research.Current edition approved Jan. 10, 2003. Published September 2003. Originallyapproved in 2002. Last previous edition approved in 2002 as C 153102.2Annual Book of ASTM Standards, Vol 04.053Annual Book of ASTM Standards, Vol 03.01.1
16、*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.standard is cautioned that the shear strength relationshipcontained within the Uniform Code for Building Conservationis
17、an empirical relationship based on tests of early 20th-centuryunreinforced brick masonry. The relationship assumes that wallshear strength is limited by shear of the mortar joints ratherthan shear through the units.5.2 For hollow ungrouted or solid unit masonry constructionthe shear strength index i
18、s measured only for the mortar bedjoints vertically adjacent to the unit being tested. When testinghollow ungrouted masonry construction, the shear strengthindex is based on the horizontal interface between the mortarand the test unit and the masonry above and below the test unit.In the case of mult
19、i-wythe construction, the measured mortarjoint shear strength index is applicable only to the wythe inwhich the test unit is located; no headers shall exist immedi-ately above or below the test unit. The contribution of anyexisting collar joint mortar to the measured shear strengthindex is neglected
20、, and this may lead to an overestimate of theshear strength index.5.3 The test procedure listed for Method A may be con-ducted as an extension of Test Method C 1197. The two-flatjack test, conducted in accordance with Test MethodC 1197, provides half of the required test setup for Method A.At the co
21、mpletion of the Method A test, one would know themeasured normal compressive stress, the deformability of themasonry at the test, and the relationship between the expectedjoint shear strength index and the normal compressive stress.6. Apparatus6.1 The following equipment is required for both Method
22、Aand Method B:6.1.1 Equipment to measure load; two options exist: (1)Ahydraulic jack with an appropriate working pressure range toload the test unit. The force output of the jack throughout itsworking pressure range shall be known, to facilitate conversionbetween hydraulic pressure and force applied
23、 to the masonry;(2) For more precision, use a load cell to measure the forceapplied by the hydraulic jack. Verify load in accordance withPractices E 4. Place the load cell between the spherical seat andthe bearing plate nearest the test unit.FIG. 1 Test SetupMethod AFIG. 2 Test SetupMethod BFIG. 3 T
24、est SetupMethod CC15310326.1.2 Steel bearing plates shall be provided at each end ofthe test jack to distribute the load uniformly across the ends ofthe test unit and the reaction unit as shown in Fig. 1. Thebearing plates shall have a minimum thickness equal to18 thevertical dimension of the bearin
25、g plate. The bearing plates shallhave a vertical dimension that is18 in. (3.2 mm) less than theheight of the unit; the plate shall be centered vertically on theend of the unit. The bearing plate shall have a horizontaldimension that equals or exceeds the thickness of the unit. Thebearing plate surfa
26、ce in contact with the loaded unit shall befaced with a neoprene pad116 in. (1.6 mm) thick; the pad shallhave a durometer hardness in the range of 50 to 60.6.1.3 An electrically or manually operated hydraulic pumpwith hydraulic hoses to pressurize the loading jack. Measurepressure using gauges calib
27、rated to a traceable standard havingboth an accuracy of 1 % of full hydraulic scale and anappropriate operating range. The pressure gage shall have apeak hold feature to indicate the maximum hydraulic pressureattained during specimen loading. The hydraulic system shallbe capable of maintaining const
28、ant pressure within 1 % of fullscale for at least 5 min.6.2 The following additional apparatus is required forMethod A:6.2.1 Flatjacks and associated equipment to measure thestate of compressive stress as described in Test Method C 1196.Test Method C 1197 describes apparatus necessary to apply aknow
29、n state of normal compressive stress to the masonry at thetest site using flatjacks.6.2.2 Use mechanical extensometers or electronic devices tomeasure horizontal displacement of the unit. The method ordevice used to measure deformation shall be capable ofdeformation measurements up to14 in. (6 mm).
30、Deformationmeasurements shall have an accuracy of at least 0.005 % ofgage length. Fasten brackets or other attachment devicessecurely to the surface of the masonry using a rigid adhesive.6.3 The following equipment is required for Method C:6.3.1 A small rectangular flatjack that is sized to fit in t
31、hehead joint on one side of the test unit. The flatjack dimensionsmust not exceed the dimensions of the end of the tested unit toprevent load application to the mortar joints.6.3.2 If load-deformation data are required, use instrumen-tation as described in 6.2.2.7. State of Normal Compressive Stress
32、7.1 The magnitude of normal compressive stress will have adirect effect on the measured joint shear strength index andmust be determined beforehand.7.2 Method A (with Flatjacks Controlling Normal Compres-sive Stress)Apply normal compressive stress using flatjacks.Place an upper flatjack two courses
33、above and centered overthe test unit to within a tolerance of 618 in. (3 mm). Place alower flatjack five courses below the upper flatjack, centeredunder the test unit to within a tolerance of 618 in. (3 mm). Asingle masonry unit, located on the centerline midway betweenthe two flatjacks, is the unit
34、 to be tested for measurement ofjoint shear strength. The slots and flatjack installation shall bein accordance with Test Method C 1197.7.3 Method B (without Flatjacks Controlling Normal Com-pressive Stress)Estimate and record the average normalcompressive stress on the unit based upon the location
35、of thetest unit in the structure and the estimated dead and acting liveloads.7.4 Method C (with Flatjack Applying Horizontal Load)Estimate the average normal compressive stress using themethod described in 7.3.8. Preparation of Test Site8.1 The location at which the joint shear strength index ismeas
36、ured is dictated by engineering objectives. Avoid areas inwhich the mortar joints appear to be nonparallel. The unit to betested must be in the stretcher orientation. Locate the test sitefar enough from wall openings or ends so that the loading jackbears against enough masonry to resist forces gener
37、ated duringloading of the test unit. The basic arrangement is illustrated inFig. 1 for Method A, in Fig. 2 for Method B, and in Fig. 3 forMethod C. At the desired location the following steps must betaken to prepare the site for testing:8.1.1 For Method A or Method B, provide a space for theloading
38、jack by removing a unit on one end of the test unit. Donot remove a unit for Method C.8.1.2 For Method A, if the joint shear strength index inopposite directions is to be determined, remove the unit at bothends of the test unit to isolate the joints being investigated.Otherwise, follow the procedure
39、 of 8.1.3. The mortar in thejoints above and below the test specimen shall not extendbeyond the vertical ends of the unit being tested.8.1.3 For Method B, remove a masonry unit on one side ofthe test unit and the head joint on the opposite end of the testunit. The mortar in the joints above and belo
40、w the testspecimen shall not extend beyond the vertical ends of the unitbeing tested.8.1.4 For Method C, remove the head joints on both ends ofthe test unit. The mortar in the joints above and below the testunit shall not extend beyond the vertical ends of the unit beingtested.8.2 For solid unit and
41、 solid grouted masonry construction,measure the width and length at the top and bottom of the testunit to an accuracy of132 in. (0.8 mm). For hollow ungroutedmasonry construction, measure the length at mid-height ofeach face to an accuracy of132 in. (0.8 mm) and measure theminimum thickness of each
42、face shell at a point12 in. (12.7mm) above the mortar-bed plane to an accuracy of132 in. (0.8mm).9. Procedure9.1 Method A (with Flatjacks Controlling Normal Compres-sive Stress):9.1.1 Instrument the test unit by attaching a dial gage orelectronic displacement transducer as shown in Fig. 1. Placethe
43、loading jack, spherical seat, and bearing plates with bearingpads into the space next to the test unit. Shim the jack toprovide a centered horizontal force on the test unit.9.1.2 Set the pressure in the two flatjacks equal to 10 psi(0.07 MPa) or less and close the valve. Increase pressure in thehori
44、zontal loading jack gradually, such that failure of the jointoccurs between 30 s and 2 min after initial loading, recordingdisplacement of the unit at small increments of horizontal load.Monitor the flatjack pressure during loading and adjust theC1531033internal pressure, if necessary, to provide a
45、constant normalcompressive stress. When the bond between the unit andmortar joints is broken, the unit will begin to displace continu-ously under constant horizontal load. This represents themaximum horizontal load for this level of normal compressivestress.9.1.3 Increase the pressure in the flatjac
46、ks to induce the nextdesired level of normal compressive stress and repeat theprocess of horizontal loading until the maximum horizontalload for this level of normal compressive stress is reached.Repeat the sequence in this manner to determine the bed jointshear stress at various levels of normal co
47、mpressive stress.9.1.4 To investigate the effect of shear force reversal on thein situ shear strength, if desired, the horizontal jack may betransferred to the opening on the opposite side of the test unit,the displacement instrumentation reversed, and the test se-quence repeated in the opposite dir
48、ection.9.1.5 Release pressure in the horizontal jack after the finaldisplacement measurement has been taken and remove theloading jack. Release pressure in the flatjacks and remove theflatjacks and displacement measurement devices. Any voids orslots created during site preparation are permitted to b
49、e filledusing the original or similar units and a mortar or other suitablematerial of a color and strength similar to the original mortar.9.2 Method B (without Flatjacks Controlling Normal Com-pressive Stress):9.2.1 Place the loading jack, spherical seat ( if used), andbearing plates into the space next to the test unit. Shim the jackto provide a centered horizontal force on the test unit. Increasepressure in the hydraulic jack gradually until the test unitbegins to displace continually under a constant level ofhorizontal load. Record the maximum load indicated by the
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