1、Designation: C1196 09C1196 14Standard 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
2、 case of 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 average compressive stress in existin
3、g unreinforced solid-unit masonry (seeNote 1). This test method concerns the measurement of in-situ compressive stress in existing masonry by use of thin, bladder-likeflatjack devices that are installed in saw cut mortar joints in the masonry wall. This test method provides a relativelynon-destructi
4、ve means of determining masonry properties in place.NOTE 1Solid-unit masonry is that built with stone, concrete, or clay units 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 regarded as standard. The values given in parentheses a
5、re mathematicalconversions to SI units that are provided for information only and are not considered standard.1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safet
6、y and health practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2E74 Practice of Calibration of Force-Measuring Instruments for Verifying the Force Indication of Testing Machines3. Summary of Test Method3.1 When a slot is formed
7、in the masonry, compressive stress at that point will cause the masonry above and below the slot tomove together. Compressive stress in the masonry may be measured by inserting a flatjack into the slot and increasing its internalpressure until the original distance between points above and below the
8、 slot is restored. The state of compressive stress in themasonry is approximately equal to the flatjack pressure multiplied by factors which account for the physical characteristics of thejack and the ratio of (a) the bearing area of the jack in contact with the masonry to (b) the bearing area of th
9、e slot.4. Significance and Use4.1 Stress is applied as pressure over the area of the flatjack. In the case of multi-wythe masonry, stress is estimated only in thewythe in which the flatjack is inserted. Stress in other wythes may be different.5. Apparatus5.1 Flatjack:5.1.1 A flatjack is a thin envel
10、ope-like bladder with inlet and outlet ports which may be pressurized with hydraulic oil.fluid.Flatjacks may be of any shape in plan, and are designed to be compatible with the masonry being tested. Typical configurationsare shown in Fig. 1.5.1.2 For determination of the state of compressive stress,
11、 dimension A should be equal to or greater than the length of a singlemasonry unit, but not less than 8 in. (200 mm). Dimension B should be equal to or greater than the thickness of one wythe andnot less than 3 in. (75 mm). The radius, R, for circular and semi-rectangular flatjacks shall be equal to
12、 the radius of the circularsaw blade used to cut the slot.1 This test method is under the jurisdiction ofASTM Committee C15 on Manufactured Masonry Units and is the direct responsibility of Subcommittee C15.04 on Research.Current edition approved June 1, 2009July 1, 2014. Published July 2009August 2
13、014. Originally approved in 1992. Last previous edition approved in 20042009 asC1196 04.C1196 09. DOI: 10.1520/C1196-09.10.1520/C1196-14.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume in
14、formation, refer to the standards Document Summary page on the ASTM website.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately
15、 depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.*A Summary of Changes section appears at the end of this standardCopyright ASTM Intern
16、ational, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States15.1.3 Flatjacks shall be made of metal or other material such that the flatjack in a slot in masonry will be capable of applyingoperating pressures up to the expected maximum flatjack pressure. See Note 2. M
17、etal flatjacks suitable for this purpose shall bemade of type 304 stainless steel sheet of 0.024 in. (0.6 mm) to 0.048 in. (1.2 mm) 0.024 in. (0.6 mm) to 0.048 in. (1.2 mm) inthickness with welded seams along the edges and incorporating hydraulic inlet or outlet ports.NOTE 2Amaximum operating pressu
18、re of 1000 psi (6.9 MPa) or less is often adequate for older existing masonry, but flatjacks with higher operatingpressures may be required for more recently constructed buildings. Flatjacks manufactured with flexible polymers that have operating pressure rangesof less than 1000 psi (6.9 MPa) may be
19、 useful for stress measurements in some historic masonry.5.1.4 Calibrate all flatjacks as described in Section 7 to determine their pressure-applied load characteristics.5.2 Hydraulic SystemA hydraulic pump with hydraulic hoses is required. Hose connections shall fit the flatjack inlet port.Measure
20、pressure using gages calibrated to a traceable standard having both an accuracy of 1 % of full hydraulic scale and anappropriate operating range. The hydraulic system shall be capable of maintaining constant pressure within 1 % of full scale forat least 5 min.5.3 Displacement MeasurementMeasure disp
21、lacements of the masonry by a mechanical gage extensometer which measuresthe distance between fixed gage points on the masonry as shown in Fig. 2. The method or device used to measure deformationsshall be capable of deformation measurements up to 316 in. (5 mm). Deformation measurements shall have a
22、n accuracy of at least60.005 % of gage length.5.4 Gage PointsUse adhered metal discs or embedded metal inserts as gage points during the measurement process. Attachgage points securely to the masonry (using a rigid adhesive for discs or cementitious grout for plugs) which will prevent movementand en
23、sure the required measurement accuracy. The gage points shall have a conical depression at their center, compatible withthe pointed elements of the extensometer. The angles of the depression of the cone and the extensometer points shall be the same.FIG. 1 Flatjack Configurations (Plan View)FIG. 2 Fl
24、atjack Test Setup for In Situ Stress MeasurementC1196 1426. Preparation of Slots6.1 Slots in masonry are normally prepared by removing the mortar from masonry bed joints to avoid disfiguring the masonry.Remove all mortar in the bed joint, so that pressure exerted by a flatjack shall be directly agai
25、nst the surfaces of the masonry units.6.2 The plan geometry of the slot shall be similar to that of the flatjack being used. Plan dimensions of the prepared slot shallnot exceed those of the flatjack by more than 12 in. (12 mm).6.3 Slots: Prepare rectangular slots into which rectangular flatjacks ar
26、e to be inserted by drilling adjacent or overlapping holes(stitch drilling) and subsequently using a drill, bar, or tool to remove mortar and produce a slot of desired dimensions with smoothupper and lower surfaces. Other tools, such as oscillating blade grinders that can be reliably used to form re
27、ctangular slots inmasonry mortar joints without damaging the surrounding masonry, are also permitted to be used.6.3.1 Rectangular slots into which rectangular flatjacks are to be inserted may be formed by drilling adjacent or overlappingholes (stitch drilling) and subsequently using a drill, bar, or
28、 tool to remove mortar and produce a slot of desired dimensions withsmooth upper and lower surfaces.6.3.2 Cut slots for circular and semi-rectangular flatjacks using circular saws of sufficient radius to provide the depth required(Fig. 1, dimension B). Use carbide or diamond tipped blades to remove
29、all mortar from the slot.6.4 Prepare slots for circular and semi-rectangular flatjacks using circular saws of sufficient radius to provide the depth required(Fig. 1, dimension B). Use carbide or diamond tipped blades to remove all mortar from the slot.7. Calibration7.1 Aflatjack has an inherent stif
30、fness which resists expansion when the jack is pressurized. Therefore, the fluid pressure in theflatjack is greater than the stress the flatjack applies to masonry. A flatjack must be calibrated to provide a conversion factor, Km,to relate internal fluid pressure to stress applied.7.2 Calibrate flat
31、jacks in a compression machine of at least 100 kip (450 KN) capacity which has been calibrated according toPractice E74.7.3 Place a 2 in. (50 mm) thick steel bearing plate on the lower platen of the compression machine. The bearing plate shall beof sufficient size to completely cover the flatjack be
32、ing calibrated. Place the flatjack on the lower bearing plate such that the edgeof the flatjack with the inlet/outlet ports is coincident with the edge of the bearing plate. Place steel spacers around the other edgesof the flatjack. The thickness of the spacers shall be equal0.015 to approximately 1
33、0.050 in.13 times the (0.38 to 1.27 mm) greaterthan the sum of the combined thickness of the two sheets used in fabrication. plus the thickness of inlet/outlet port used infabrication of the flatjack. Place the upper 2 in. (50 mm) thick bearing plate on top of the shims and flatjack, and align it to
34、 bedirectly above the lower bearing plate. Position the bearing plate/flatjack/shim assembly on the lower platen such that the centroidof the area of the flatjack is within 14 in. (6 mm) of the axis of thrust of the test machine. The calibration setup is illustrated inFig. 3.7.4 Raise or lower the m
35、oveable platen such that the non-moveable platen is both platens are in contact with the top bearingplate.plates.Apply a pre-load sufficient to provide full contact between the bearing plates and the spacers, equivalent to 10 psi (0.07MPa) over the gross area of the flatjack.FIG. 3 Flatjack Calibrat
36、ion Setup (Elevation View)C1196 1437.5 The distance between platens must be held constant during the calibration procedure. Fix the displacement of the testmachine at this point if using a displacement-control machine. If not, attach displacement gages (mechanical or electrical) suchthat the distanc
37、e between platens established by the procedures of paragraph 7.4 can be held constant when using a force-controltest machine.7.6 Pressurize and depressurize the flatjack three times over the full operating pressure range. Do not exceed the maximumflatjack operating pressure.7.6.1 While holding the d
38、istance between the platens constant, increase the pressure in the flatjack in equal increments to within5 percent of the maximum flatjack operating pressure. Use at least 10 equal increments between 0 psi and the maximum flatjackoperating pressure. At each increment, record flatjack hydraulic press
39、ure and force applied by the test machine.7.7 Calculate the load applied by the flatjack as internal pressure times gross flatjack area. Plot flatjack load versus loadmeasured by the test machine with the flatjack load on the horizontal axis of the plot. The slope of the line is equal to the flatjac
40、kconstant, that is, the conversion factor:Km 5P machineP flatjack (1)7.8 Recalibrate flatjacks after using five times or when distortion appears excessive.8. Procedure8.1 The location at which compressive stress estimates are performed is dictated by engineering objectives. The basicarrangement is i
41、llustrated in Fig. 2. At the desired location or locations the following steps should be taken:8.2 Select and mark a visible line on the masonry to define the location and length of slots to be formed.8.3 Attach at least four pairs of equally spaced gage discs or embedded plugs vertically aligned ab
42、ove and below the slot asshown in Fig. 2. Each row of gage points thus formed shall be equally spaced above and below the flatjack. The minimum gagelength shall be 0.3 times the length, A, where A is the length of the flatjack as shown in Fig. 1. The maximum gage length shallbe 0.6 times the length,
43、 A, of the flatjack. The first and last locations shall be located not less than 18 of dimensionAinward towardthe center of the slot from each end, as shown in Fig. 2.NOTE 3Alternative instrumentation configurations are acceptable if controlled laboratory tests are conducted to verify the validity o
44、f the alternateinstrumentation approach. Examples of alternate configurations are shown in Fig. 4. These references provide additional information about alternateinstrumentation for flatjack testing.3-58.4 Measure the initial distance between each pair of gage points.8.5 Prepare the slot (see Note 4
45、) (see Section 6) and record the measured slot dimensions and the time. Clean slots of all mortarand brick particles prior to the insertion of flatjacks.NOTE 4The location of the slot shall be at least 112 flatjack lengths from wall openings or ends.8.6 Repeat step 8.4 after the slot has been prepar
46、ed to obtain the initial deviation from the original gage distances.8.7 Insert the flatjack into the slot. Shim as required to achieve a tight fit and bridge over any interior voids in the masonry. Seethe Annex for a description of flatjack shims and their use.8.8 Connect hydraulic hoses and fill th
47、e calibrated flatjack with hydraulic oilfluid until pressure begins to develop.3 Ronca, P., “The Significance of the Gauging System in the Flatjack In-Situ Stress Test for Masonry: Experimental Investigation,” The Masonry Society Journal, Vol 14,No. 1, August 1996.4 Schuller, M., “Flatjack Methods f
48、or Diagnosis of Modern Masonry,” Proceedings, On-Site Control and Evaluation of Masonry Structures, Binda, L., deVekey, R., editors,RILEM, 2001.5 Coombs J., Tanner J.E., “Development of Laboratories for Masonry Testing and Non-Destructive Evaluation,” The Masonry Society Journal, Vol 26, No. 2, 2008
49、, pp.9-20.FIG. 4 Examples of Alternative Instrumentation ApproachesC1196 1448.9 In order to seat the flatjack and any shims, pressurize the flatjack to approximately 50 % of the estimated maximum flatjackpressure (which corresponds to the estimated compressive stress in the masonry). Reduce the flatjack pressure to zero.8.10 Increase pressure in the flatjack to 25 %, 50 %, and 75 % of the estimated maximum pressure holding the pressure steadyat each level. At each increment, measure and record the distance between each pair of gage points. Three repetitions ofd
