A Model Study of Horizontal Pressures on a Retaining Wall Due to Concentrated Surface Loads and Electrical Strain Gauge Pressure Measurement Citation Curtis, Thomas Grey and French, John Martin (1944) A Model Study of Horizontal Pressures on a Retaining Wall Due to Concentrated Surface Loads and Electrical Strain Gauge Pressure Measurement. Master's thesis, California Institute of Technology. doi:10.7907/f77f-tj19. https://resolver.caltech.edu/CaltechTHESIS:03312025-202919862 Abstract No abstract. Item Type: Thesis (Master's thesis) Subject Keywords: (Civil Engineering) Degree Grantor: California Institute of Technology Division: Engineering and Applied Science Major Option: Civil Engineering Thesis Availability: Public (worldwide access) Research Advisor(s): Converse, Frederick James (advisor) Hudson, Donald E. (advisor) Thesis Committee: Unknown, Unknown Defense Date: 1 February 1944 Record Number: CaltechTHESIS:03312025-202919862 Persistent URL: https://resolver.caltech.edu/CaltechTHESIS:03312025-202919862 DOI: 10.7907/f77f-tj19 Default Usage Policy: No commercial reproduction, distribution, display or performance rights in this work are provided. ID Code: 17116 Collection: CaltechTHESIS Deposited By: Benjamin Perez Deposited On: 01 Apr 2025 23:19 Last Modified: 01 Apr 2025 23:29 Thesis Files PDF - Final Version See Usage Policy. 27MB Repository Staff Only: item control page

A MODEL ON STUDY OF HORIZONTAL PRESSURES A RETAINING WALL DUE TO CONCENTRATED SURFACE LOADS AND ELECTRICAL STRAIN GAUGE PRESSURE MEASUREMENT Presented as partial ere di t tor the Degree of Master of science in Civil Engineering Thomas o. Curtis John M. French California Institute of Technology February 1944 TABLE OF COU'ENTS Page Objectives and Scope 1 Equipment l Ga.age Assembly Ce.libration 10 i\tsts 14 Trials - 1, ' 3, 2 & 24 -4 Trials - ,. 6, 7, & 8 Trial Trial 17 19 22 - 11 - 14, &. 16 Trials - l '7 18, 19 Trials t Trials 15 & - 20, 21, 22, & 23 24 26 26 Conclusions 28 .A.eknowledge:ments 31 Reference 31 .Appeadix 32 ILLUSTRATIONS AND GRAPHS Page Gauge Assembly Detail 2 Wirin.g Daigram 4 Photographs of Equipment 5 Testing Box Detail 7 Gauge .Assembly Mounting 8 Equipment Details g General View of Equipment ll In Place Calibration Device 13 Test Graphs Figure 12 16 Figure 15 18 Figure 14 20 Figure 15 21 Figure 16 23 Figu.re l'l 25 Figure 18 27 :71gure lt 2'1 * · oBJEO':rlVES AND SCOPE At the onset the objective or this research waa to meaa·~ure the distribution or horisontal premsures against a model retaining wall with the application of a concentrated or point load at the surface and near the wall-. However, as the work progressed and with the decision to attempt to utilise electrical strain gauges .for pressure measurement, the objective was expanded. To our knowledge these gaugea had not been used be1 \ fore in a similar capacity; therefore; the objeotiTe also became that of testing t~e gauges in this capacity. It must be realised that the original objectl'ive was foremost and wi.1 1 recei~e more conaiderati9n. ' Due to the comparatively few tests that were performed and the conditions of these tests, the results should ha.Te no general significance. At the time o.f the writing, tests are being made; and more conclusiTe results may ultimately be reached. Also, since the work was done with a model, the ne- cessity of proper corrections for application to working conditions is apparent. EQUIPMENT The equipment may be classed in three more or less distinct groups. They are the gauge assenblies, bridge, and elec- trical system; the test box and frame; and the loading deYice. The gauge assemblies were the most difficult and troublesome phase of all the equipment to develop and put into opera- 3 tion. Each gauge assembly consisted of a thin-walled brass tube with two galvanized iron circular plates soldered on the ends. Cemented with .g lyptal cement to the t~be in a longitudinal direction, symmetrically spaced, were three 400 ohm aircraft strain gauges made by Douglas Aircraft' Company. The gauges were wired in series and the ends wrapped with silk thread and cemented down. The series wiring was decid- ed on for greater sensitivity, simplicity of switching, and the fact that three gauges in series tended to iron Qut any irregularities due to bending stress. Six of these assefu- A drawing blies we re made up and installed in the test box. of a gauge assembly is shown in Figure 1. The brit/.ge consisted of two 400 ohm legs, two 1200 ohm -. legs with a twelve volt battery and a galvonometer connected across them. One ot the 400 ohm legs consisted of a 597 ohm resistance, a coarse adjustment of one ohm division, and a fine slide wire adjustment with a vernier dial. This part of the bridge had been previously built for use in the Testing Materials Laboratory of the California Institute of Technology. Any o t the gauge assemblies could be made _a 1200 ohm leg. The assemblies were switched in and out of the cir- cuit by a six-position selector switch. This switch consisted of three selector switches mounted on the same shaft wired in parallel. resistance. This parallel wiring served to minimize switching The wiring diagram is shown in Figure 2. 3 is a photograph of the bridge. Figure The test box is a. box made of 2x6 planks ~piked togeth- er with soz,ewed , angle~iro.n co:rn~r rei~foreeme~ts. . ~e. box measures sixteen a:i;id .one"!'ha;lt 1noij.es deep . andt~enty-rour by twenty-four inches it?- plan view. Above this is a .fraxne of three 6 in,ch "I" beams supported on t'our 2x4;. columns. frame carried the load from th~ . ja.ok to the sdil. This The whole device is about three feet wide, . three feet long and t"f>'1f and one-half feet high. '' Figures 4 and 6 show the box and: frame. In one side of the box six one--and-one-half inch holes were drilled to house the gauge assemblies. ln line with these holes on the outside of ·the box, was a gauge assembly support (see Figure 8) made of a one-and-one-fourth inch square reinforcing bar, ground smooth on one side and w~lded to two steel plates which were fastened by screws to _the box. The gauge assemblies were passed through t}?.e holes, small end toward . the support, and held up by smooth-headed tacks in the holes and by wire strips.- on the outside of' the box. A marble held in placEt by tape . was used to insure een·• tral loading of the gauge assemblies and shims were us~d to make the face c,,t the ass_e ~blies flush with the inside, of the box. A strip of heavy paper was taped to the inside f'aoe of the wall o'f'er the assemblies to protect them f'rom soil particles. Photographs of the installed gauge assemblies are shown in Figures 5 and 7. The loading device consisted ot a thirty ton capacity "Black Hawk" hydraulic jack, with a beam gauge to measure the load. The jack was placed on a pile of six inch diameter /0 wooden plates to give the right height. loading device is shown in Figure 9. A photograph of. the The be8.111 gauge had . been previously calibrated; however, as a check it was plaeefil. in the 30,000 pound testing machine and loaded with the jack. The original calibration was checked as 0.001 inch deflection : 40 pound load. The entire test set up is shown in Figure 10. GAUGE ASSEJQLY CALIB:tlATIOlf The calibration of the individual gauge assembly was qui ~e complete and performed with considerable e:a ~e, The as - semblies were first calibrated out of the test box in a 30,000 # Riehle Testing machine. The allowable s~ress of the brass tube was calculated., and the calibration loads were applied to a maximum considerably below this value. The loads were applied in even increments up to about 800 pounds with readings of the bridge being taken at each point. The load wa:s then re:moyed in even decrements with readings as before. A pronounced hysteresis effect was observed with the first attempt at calibration which led to more investigation of the electrical strain gaugeo Upon consulting with engineers at Vega Aircraft Company who were familiar with the electrical strain gauge, it was learned that this hysteresis effect was not uncommon, a.nd that with proper treatment could be removed or considerably reduced. The application of general heat to the brass tube in sweating on the end plates may have produced interna.1 1.2. stresses, the removal of which was accomplished by alternately loading and unloading each assemb ly several times. This apparently removed a good part of the hysteresis effect. Also, the opinion of the men consulted was tha.t the cement u sed on. the gauges would show some slipping until it had set for as long a3 two weeks. With the realiza,tion that our first calibration had been attempted. only one \Veek after the appltcation orf- gauges, it was conjectured that this :f'ailur•e of the cement might have be~n present. All owing for these fa.ct;ors, the testing machine eali- 1':ration was completed with reliable res11.lts, (See calibra- tion curves in Append~x.) The gauge assemblles were then lnst,alled in ,t he test box,.. s.nd were c.a:librated in place. 'l'b.ia "in place" calibra- tion waa. accomplished by bu)+1.d.ing a. simple lever arm de- ~,iee • ( See Figura 11). A 50 pound spring bala.n ce was used :bo measure the force on the long a.rm; and by applying• the multipl:tcation facto:r ., the load on the gauge assembly was computed. The load was spplied to the assembly through a heavy washer and a marble, thus minimizing any bending ef- fect. Even increments of los.ding were e.pplied up to 350 pounds with subsequent decrements to 1:ero. Of course, bridge read- ings were taken e.t each point of the loading and unloading cycle. The results of the "in placeff calibration agreed substantially with those of the machine calibration. Due ' to the relative crudeness of the "in place" calibrating device the maoh1ne calibration was ta.ken a.s a basis for the first tests. This decision was justified because of th{) close a- greement of the two methods. (See calibration oun·es in the Appendix.) Before starting the testa,, plaster sand was gently placed in the bo~ and was not compa.ctedo 'l'he test technique was as ,follows: first., a n9-load reading of the bridge dial was taken; second, a load. was applied with the jack; and third, e. br1dgee d1a.1 reading of the loaded gauge assemblies was ta.ken. · The no-ioa.d reading was taken with the weight ot the jack assembly on the sand. With the gauge equations ot the form L • K (R - Ro) an.d the no-load reading taken w:tt.h the sand and jack in place, the computed pressures were the extr~ pressures due to the liTe area load. A no-load reading had to be taken with eaeh separate test, due to the obserTed change of gauge assembly resistance. 'l'his change was probably be- cause of heating effects. Because of the fact that extra pressures were measured, negatiYe pressures occasionally resulted. This merely in- dicittes a dec1•ease in the equivalent fluid p1.. essure of '.!;he soil. IS Trials 1, 2, 3, e.nd 24 (Figure 12) 'l'he curves of these trials show the general form of a typical pressure curve- Note the pressure concentration nea.r the top of' the box. Trials 1, 2, 3, and 24 were a.11 run with a 560 pound > ; load on a s:t:x: inch circuler plate with its cente~ eight inches back .from the wall f'aoe in line with the gauge assemblies. Trials 1, 2, and 3 were all run with the eand in a fairly undisturbed state. However, it was observed in these three trials that the pressure tended to decrease with the suc(~eesi ve tx•ials; that is, the pressures of trial l were greater than those of trial 2, which ·1n turn, were greater than those of trial 3. '!'his was probably due to some compac- tion effect of the sand. These tests were run in imra.ediate succession. With the a.ppiicatiori of the load for trial 1; the plate Siink about one .. and one-half inche_s . No .further settlement was obserTed. tests 1 nnd. 2 gauge assembly 4 was inoperative; in test 3 gauge assembly 6 did not :t'unction. Trial 24 was run arter the sand had been stirred up. The plate sank th~ee-fourths of an inch when loaded. measurl9d presau1.. ee compared well with trials The 1, 2, a.nd 3 ffin ,: +07~· f----+--4 ---+--+---"--.-1--:e-- --+--+----t----ir---+--+'----t----1-'--+----,.... ~ I, -··-· ~---+--+- . •:~ L~-t•. -+----+- - :: .: ; i - . ; '. : • -, -- -- . I ' I -• fJ ___l.l.:_j ;r.:~t\:_ I~: .:.:__ I • ' ,I • . 1- . . . . '. : :.: : : i-·-- -- . . -..-..-- :-:· ;_--: -.:: ... . · • . . .. ·•·. ··. .. . . . . . . . . . . . . . . •·· . • . .. . . . • ··. ·. -·' -... . ' . . . .. . .. . ,... - ~-- • ., t:-1ci ~·~· 1··· .. \ ., -- 1- .':l • ~ - - I . ~:-; - '. -- .- t"~- . ·• . N~ ·:1<: =; :•~·-1·:: -4:..:._:: a~J l_:_::l __d: ·:: •1,::• I: • -+-----4- - Trial 4 (Figure 13) This trial shows the ef'.t'eot of soil failure on the pre:Et, .. sure distribution. Soil failure is deTined as the condition of sustained maximum load and continued settlement. The plate size and location was similar to trials 1. 2, and 3. The failure load -.was 680 pounds. '!'his test immedi- ately followed trial 3 • . HegatiYe pressures were obseryed on the two . top gauge assemblies. which indicates a decrenae in the equiTalent :f'luid pi-essure of the soil. The high.eat observed pressures on the three bottom gauge assemblies were recorded on this trial. One explanation of the pressure distribution (See Figure 13) under failure loads may be this: The load punches its way . into the soil and gives a high pressure directly under the load at the bottom ot the box. Because of restraint. this pressure is transmitted to the box walls. The decrease of pressure at the top ot the wall is caused by a. collapse of the soil grains in toward the moT1ng core or soil directly under the load. ·-- --•-+' -·-- . ' i /9 Trials 5, 6 1 7, and 8 (Figures 14 and 15) The pressure distribution curves of these tests are shown 111 Figures 14 and l5o All tests of this series were run with a ten-inch circular _slate with its oente1-- 8 inches back f'l"om the wall .face, in line with the gauge assemblies. Teats 5 e.nd 8 had a. 1000 po'I.Ulii load; toat 6 had a. 1500 pound load; test 7 had a 2000 pound No appreciable settlements were observed. load. These tests immediately followed one anothe1•. '?est 6 wa.s computed two ways. the no .. load readings of test 6. no-load readings ot test 5. Test 6a was oomputed with Test 6b was computed with the fest 6b may be disregarded. It was observed that the pressures of teats 5 and 6a were roughly ~qual. 'l'hoy were plotted as one curTe. Test 7, with a greatel" load than any of this series, shows pressures less thP...11 tests 5 and 6• while test 8 shows the lowest pressure o:f this s~r5.ea. These results oonf:trm the statement of' the com- paction ef.fect pz•ev1ously notedo It was obsez•ved the pressure on the bottom gauge asaem- bly was g;r.•eater , than the pressure on the one immediately abov.~ i:n trials 6 and s. trials. ~his phenomenon was obserTed in other ,-J ~--___-_I-~-7~~ I ;_ I ' i------i- - tc-- --rr __J _;__:_l___ ~ I ·:7_18 :__J~~- -___ -t•+-+ :--' r _· +·_L , __ Tn I • ·- , + I -- --.,.-- , T1 I I -r-·T7---T-~-r-~r -r-1 · - - ------ · - -T--~T-:-7 I : ~~~ i 1 i ~ ••• •.•-T1-1tt_t· -_- -- l-}_J}Jj , --- --r . , t _i: •:J__ $~-B+ti$ -: -F.:_TJ: +-' ~' -le,-~- :: 1 J I i I ,. ·-. • •• .., ., -~ .:.1 i . • -• I I • +- ' r --:-t·--+--r t -·--"'-~li~~-,-~ t_ L-l~~~' i ~-L--- 1 I f : - i -1-~:~!~t .L r -~+, ---1-----+~·-7 I : . - : · · , - -- -•· •• _:~ -- • 1 . 1 I. [ _· I 1 Trial 11 (Figure 16) ~is trial was run with n load Tery near the- wall face . A six-inch circular plnte with its center 4 inche·s back from the wall face in line with the gauges assemblys was used. The load was 520 pounds. The pressur~~ distribution on this test followed the typical form. However, tht"-! pressures were smaller than any of the other trials. the work of Spangler. gauge was observed. Thi.s trj_ a.l does not agree with The greater p1"e.rnsur·e on the bottom No explanntion can 'b@ offered a.s to why this test did not give pressures larger than those w:i.th the load fa.rt.her e.wny from the wall. i -----r; -'------1 ' I I • - ·- -r- - Tests 14 and 15 (Figure 17) Tests 14 and 15 were performed in the same series; that is, the sand was completely sti!•1~ed and loosenod before test 14 was begun and was not loosened agein for test 15 . figure indicates, test 14 w-as l'Un As the with a total lor.d of 560 pounds on a. six-inch diru.neter plate, the center of whi(Jh was 8 inches from the active face of the ,.vaJ.1 and in lint!;'! with the gauge assemblies. With the a.pplioation of the load, the plate was observed to sink about one i nch into the s:md. The obs erved results of t ost :·.14 were s omewhat loweJ' than was ob.. served in test aeries or..e, and. the distribution was rather This observed inconaistency may have beHn duo to the poor. err•a.tic nature of the st1--ain gauges; however, the results of' test 15 were better. Test 15 followed 14- i.mrnediately. By simply releasing the load of 14 and ta.king a set of' zero r eadings, 15 \'HJ.8 begun . The applied loe.d was again 560 pounds , nnd the reesults showe;d a good pressure distribution with magnitudes somewhatnbelow test 14 . This phenomenon had. been noticed. be fo:r•e e.nd was be- lieved to have been caust)d by a compacting effoct in the sand. The a pparently propel'.' distribu tion indicates that nthe gauges were. functioning properl;r. '.rhose tests sho w- the result that the pr~ssur(4 at the bottom gauge war3 higher tho.n that a t the second gRuge from the bottom. This wa.s noticed to be the case generally in all the tes·ts , and ·l;his is in agr1;>,ement with the results obtained by Spangler. This higher pressure:,at the bottom was possibly due to the floor of the box; that is, the floor offered resistance and thus increased the pressure a.t the bottom. Trials 17, 18, 19 These cussed. (Figure 18) trials were of' these.me series a.s previously dis- The applied load in ee.ch case was 560 pounds, and l witl,i "che initial application of the load the plate sa.nk about • one 1inch. Plate and location were as in tests 14 and. 15. ( ' The it distribution of pressure was again quite consistent with \ the fmagnitude varying considerably. ' ; Test 17 compares quite well in magnitude with test 14 with tests 18 and 19 increasing somewhat. It must be noted that the increase of the pressures after 17 would indicate the.t the idB.a of compaction, as preTiously stated, is in error; however, the decrease was generally the case and tends to verify the statement. 'l'n.e slight increase in pressure at. the bottom gauge was again obse~ved except in test 19. Gauge assembly number 6 was not .functioning in test 19. Trials 20, 21, 22, 23 (Figure 19) This series was performed with a 6 inch diameter plate and centered 8 inches from the face ;n line with the gauge assemblies. The applied load was again 560 pounds, and the plate sank three-fourths of an inch. The sand was loosened before test 20, and the test was run in the pre-described , " . .,z_ 7 manner. The distribution was quite good with the magnitude in accord with trials 18 and 19. After test 20, it was de- cided to let the equipment stand unloadnd for one-half hot~r before making another• test. Af ter this period of time, test 21 was performed with sero readings being taken and the load ~PP+ied as before. Aij rae.y oe obs<!;t'Ved in Figure 19, the magi,.itudes of pressu:r·es _1n test 21 y:rere mvre than do1:tbl0 thoaE,, of 20. This ind.ioF.<.tes a definite tim~ effect in the sys~em which may haTe been due to external temperature. It may}haye been due to internal temperature; that is, ~eating ,, within the the electrical circuit, or 1t may-ha.Ye been due to an actual redistribution of the pressure within the sand, It is apparent that more investtgs.tion must be made with respect to this phenomenon. Tests 22 and 23 were run immediately with results in accord with former t.r1als. The odd shape of the curve for test 23 may have been du~ to ~rratio guages or partial failure of the sand. OOBOLUSIONS The following conclusions are dr~wn from the data obtained in the researcha 1. No exact formula may as yet be given for the hori- zontal pressure distribution one. retaining wall under a conoentered load on the soil surface. 2. The pressures observed on this model were five or ten times greater than the pressures observed in similar ;!.9 studies· on large walls. 5. The use of a. small, rigid box for these pressure measurements undoubtedly gives h1gher pressure because of the restraint or the soil particles. !'he value or model studies in a soil pressur•e problem 1s open to aerioue questioning. 4. A scale factor could probably be worked out to cor- relate t'.he observatios on models and full size walls. There is a time-compaction reduction of the pres- 5, sures. This may he explained as primary lateral distribution of the load through the soil, then as the aoil compacts, a secondary distribution or the load downward t -o the bottom of the box. 60 The pres su r e at the bottom of the wall tends to be greater than ·th.e :prossirrc 1,mncd:t n.teJ.y nbove tho bottom, which was con.j octured by Spangler to be du:::; to the bottom 01~ the wall, that is, th~ :floo!' of. the boz in this case. 7. Electrical strain gauges afford a convenient and simple method of measuring strains a..-r1d forces. However, tem- pernt,,1 re effocts may be consid~i·nble, as they probably were in th ifs work. It 1 s b ~ l5-t~T~d t~at e. gauge assembly with the separate gauges forming the l~gs of the bridge would smooth out temperature effects. The NHrnl ts showed g:>od consistency in the distribution of hor·i~ont r1l 1, ::-~, s sure against the wall but apparently showed little consistency in the magnitude of these pressures. 3u It is believed that the variation in .magnitude was due to heating effects in the strain gauges; however, there may actually have been a redistribution of pressure in the sand. If the ef'fe ct 11vas one of gauge heating, 1 t may be corrected as suggested by making each side of the bridge an active strain gauge. 8/ Aoknowledgttmnt Th& aut,b.oro wish tc> grat:etiilly acl'.n.owlod{!'P the assistance and adY1oe recieved i'rom. Profeasor 11'Ndriok 1. Conver• and Dr. Donald Eudeon 1 ~t;the oaUtorn:J.a :tnatttute ot 'leehnology •. and t-i~•..)m Mr • .,;a lter Hurty.ot tho Vega Uroratt company. H~teronce :~pangler, M. ll ,, Horizontal Pl"8asuras ou Y\$taill1ng walls Dtte to concentrated ~iurtace Loads, Bulletin 140, 1900 Iowa ~1nettrlng I~xperiment .:.,tation, Appendix tota.4 ~ .lbth. 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B ~1. ,g. a.,93.1 P.....fJl.• 9 2,,..£31.G 2.-ao-.3 2-89. 9 4. 9 1. e * 11,.5 6.4 .., ... ~s.e 15. S 12. a * 10.2 9. 2 3-2 2,..,11 . 2 ~ * S-1.8."I 2...1,..1 3-07.o 3-.0 0.0 l-,6 2.0 * M. 3 u ., e.e Load lal,am tlrup lA O.uge L'eptl\ l\las. !lo. 1·. •,,. , 5&0 l 'l\', 2 3 !I}.: ¥ • 5 6 Mal 1tso D -56◊ 1 14 a-et.e ,., 4 * a 3• 94. 3 2-155. 5 2-02. , 2- ,1~. o 2-P:At.7 2.- 1.12. t a-21 . 0 5-0S. 4 3-19. S t-~e.o s-:w.o II' * Q * 2-517 •.2 a-ea., 2c4"15. 6 3-19.4 2• 26.0 3-17.$ 2-1m . , 2-•151 . 2 Bait hour elap.M d ootween so n.nd 21 'ball tr 21 D 14 1 560 8 3 4 5 6 1'.rt&l. Ml2. n 8" 14 l 560 2 0 4 5 6 ,., ,., 2- 90. 0 2•@9 . '7 "' ~- 2m. ia 2• 53. 5 2-80 . 9 2• 92. 3 2• 21.9 ►25 .'l ►20.1 #}• (}2. 4 'ij! * >Iii &-15 . 6 ($It 2- ei. a 2•90. 9 "' 2-100 . ,1 1(1, ;iii 4. 0 z-28.o 3-e5.o a-1~.a *z~ 2. 2 1. s !!> a. 2 1. 2 'Ir 0. 4 "' 1;y, F 1 l'bl:l11 ,~1 . u .1 18. 7 ~., is.•4 10. • $.2 1.$ l.6. $ a.s a.s s.& r>. o 1.oat.t sank 1/4'' 1an. ae 5. 4 4.0 i .4 l .5 - 1.0 ~• 06 . '1 s.g :,,,. ~.l ~ 1s.w * 2$. 2 l .t:a. e 15 . 9 10. 4 *~ U 'l.5 ,.1 1i . 1 Ii< -• 7. 5 * 7 3. 6 55. 2 ,a.a ... 5. 6 e.9 Q.1 * 7. 4 * e&. 2 ;§< m.a t;.9 'e'!. 7 32.6 .~ #. 41.f 56. ~ a-G.a 2t1!.. 6 31. 5 Jan. 86 Plate *,v * ... Ro K Ian et. G" Plate $'ff R sand LootSened , B•S':'e4 * 5 &-oo.o 2- 1:So. e * * 4 Rob a-ee.1 6 >¥ :?late 5 i1 2 n'' 2•.fW.4 t • BEI. ~ &-96. 3 2• £.e.. o 1-2us. 1 5-Ui . o ,ii , .o 56.4 so.e *' 15. 9 ,1 . 0 it- ~ .2 ~o. 4 2. 1 1. 3 1. s al< 111.e 4. 4 'I' * ~,oc 14.~ ; ;,.':".-;" -- 11.a 9. 9 5. 4 e.2 TEST DATA 6" Plate Load B;Ja.m Gauge 20 Gauge tepth l 2 3 4 5 6 Trial 14 i/ 24 D 8" 560 :e 2 3 4 5 6 - Ro R R0 R * * * 2-6 2.l 2•90.l 2-100.2 2-60.6 2-89. 4 a-99 . 6 1.6 o.7 *.,;. 2-G0. 4 3 ... 24.7 2-2.e.? 3-26.3 1.7 * 5-14.l 3•14 . 9 lbs. No. 800 Jan. 25 Lead sank l" o.e 1. 4 -o.a IC F p * * * * * * 12.4 4.6 ,.o 2.e a.~ 14.2 8. 0 10.i rs.a -6.5 -~.7 4.9 Jan. 25 * * * * * * 4.3 3.0 * * * 99 .2 30 . 4 iG.O 17.l 22.8 1 2 .9 • 2.5 * 20 . 9 $.l 12.2 11.e 12.0 ra5.o 2- 50.6 2-86.9 2•96.6 2-2e.9 3-M.4 1.1 * 3-14. 3 3-u~ . 3 1.s * 2-e2 . t!. 2-90. 2 2-\',H ).6 2•29.4 4. 6 7.0 MACJUNE CALIBRATION TE;.5TS Gaugt .Assembly #1 Load (lbs.) e Bridge Dial 4 - 195 310 490 490 650 Gauge Assembly #2 s- 93 . 7 J..20.0 133 . 5 590 615 515 4 - ti8 a.o 44 . 0 20 . 0 590 27 . 5 11.2 158.2 128.S 108.5 93 . 0 0 0 100 200 320 420 430 154. B 810 Load (lbs.) Bridge Dia,l 2 - 9Sl .5 3 ... 4:4 . 0 5'1 . 5 620 500 400 400 290 35 . 5 19. 5 7.9 2 - 3 - 140 0 90 . 6 109 . 3 119. 5 132. 3 4 - 145. 2 152 . 6 5. 9 19 .. 5 31.5 50 . 0 28 . 0 3 - 7. 5 164.7 137.8 117 . 5 98 . 5 153.4 135.2 115. 3 94. 0 Gauge 6 saambly #4 Gauge Assembly #3 0 13.0 200 300 400 450 450 550 670 810 610 450 450 300 9 .1 oo .o 800 0 Bridge Dilll. 120.0 140 . 0 157.4 700 130 Lea,d (lbs.) 89 . 8 Bridge Dial 0 110 4 - 118.7 200 330 450 450 135. 3 146. $ 5 - 600 705 37 . 3 28 . 4 1.5. 0 600 150 0 o.o 18.6 28 . 3 790 700 500 500 400 300 8? . 2 106. 5 1.6 4 - 147 ..1 1.3 5.2 123. 0 l.08.2 85.4 MACHI NE CALI]3Rt\.TI01:1 TESTS Load {lbs.) 0 100 200 355 470 550 550 670 800 680 540 540 340 i20 130 0 Bridge Diaj Load (lbe . 3 - 0 1:30 260 400 500 730 73. 2 87 . 9 100.0 1aa.o 4 - 3 - l a9 . 4 l.60 . l 3. 8 Z0 . 4 36 .3 23 . 2 8. 2 156 . 4 131.8 llS . O 107 . § 89 . 7 810 6SO .Sl.O 370 180 0 Brid.ge Dial 3 - ll. 6 32. 0 48 . $ 65 .1. 78.9 10'"/ . 9 115.3 98 . 2 so.:a 63. 0 42. (i 19.l I:N" PLACE CAL.DmA.TION TESTS Lea4 (lba.) 0 100 200 300 350 200 100 o Bridge Dial 2 - 34. 7 43. 6 51. 2 6l. 8 $6. 3 5i. S 48. 4 s1.a Q 50 J.00, 200 300 350 200 lOO 0 0 Q 100 00 100 so 200 200 250 250 350 360 250 .2 00 lJ;}O 100 0 0 Gauge Ae.s embly #6 Load ( lbs. ) 0 50 100 100 800 200 300 360 000 100 100 0 Bri dge Dia: 0 60 J. - 125 1:31 . 7 100 200 1s1. a 153. ti 7.0 200 260 2 - 100 l - lt}6 .4 148.6 270 200 200 50 0 12 . 3 1.a. 2 9. i 141. 6 134. l