Research on earthquake resistant structures by Constantine A Markellis A THESIS Submitted to the Graduate Committee in partial fulfillment of the requirements for the degree of Master of Science in Civil Engineering Montana State University © Copyright by Constantine A Markellis (1949) Abstract: no abstract found in this volume EESEABCH OMEARTHQUAKE RESISTANT STBtJCTUEES by CONSTANTINE A. MAHtBLLIS A THESIS Submitted to the Graduate Committee In p a rtia l fulfillm ent of the requirements fo r the degree of Master of Science In C ivil Engineering at Montana State College Approved: In Charge of Major Work /\\i 2- ACKHOWIEDGEMEHT I am gratefu lly indebted to Associate Professor B. C. DeStort of the Department of C ir il Engineering of Montana State College fo r h is guidance throughout my Graduate Work and fo r h is help­ fu l information and assistance with ny Thesis. I am also indebted to my ty p is t, Valencia Kabalin, and to my friends in Hudson House, Montana State College, fo r th e ir cooperation in correcting the English of my paper. C. A. M. 9 2 6 1 1 -3 - TABLE QP CONTENTS Patte g ACKSOWLEDCTfflSHT------ -------- --------------------------- -- ----------------- -IBTRODOCTICai_______________________________________________________ 5 CAUSES CF EABTa^UAKES ----------------- ---------------------------------------------------- Q EABTBQUAKE WAVES------------------- --------------------------------------------- 12 DERIVATION OF THE HORIZONTAL SEISMIC FORCE---------------------------- 15 Horizontal forces produced by eona of the disastrous earthquakes of the world - - - - - - - - - - - - 17 INVESTIGATION OF EABTHQIUAKE STRESSES IN A BUILDING FRANE - - - - 19 ELANS OF THE BUILDING FRAME INVESTIGATED-------------------- -- _ 20, 21 COMPUTATIONS OF THE MOMENTS--------------------------------------------- -- - 22 Momenta due to the v e rtic a l loads on the r o o f --------- -- — 22 " " " " " " " 5th f l o o r ------------ 25 DESIGN OF THE CEILING BEAM K-K3 ------ ---------- --------------------------- 30 HORIZONTAL WIND SHEARS------ -- ------------------------------ 36 HORIZONTAL SEISMIC FORCES BY THE LOS ANGELES CITY BUILDING CODE ----------------- -- - 37 HORIZONTAL SEISMIC FORCES BY THE UNIFORM BUILDING CQDR------------ 39 DIAGRAMS FOR WIND MOMENTS ---------------- kl DIAGRAMS OF EARTHQUAKE MOMENTS BY THE LOG ANGELES CITY BUILDING CODEREQUIREMENTS------------- 46 DIAGRAMS OF EARTHQUAKE MOMENTS BY THE UNIFORM BUILDING CODEREQUIREMENTS------------------------ 51 -4Piage DESIGN OF BEAM HS Uniform Building Code requirem ents------ -- - --------- -- - — 56 Los Angeles City Building Code requirements ----------------- - 57 DESIGN OF COLUMN GS-HS Uniform Building Code requirements- - - - - - - - - - - - - 58 Los Angeles City Building Code requirements --------- -- - — 60 DESIGN OF FOOTINGS--------------------------------- ---------------------- - 6 l EESION OF TIES BETWEEN FOOTINGS BI THE UNIFORM BUILDING CODE REQUIREMENTS ----------------- 69 DESIGN OF TIES BETWEEN FOOTINGS BI THE LOS AIKffiLES CITT CONCLUSION------------- 73 LITERATURE CITED-------------------- -- -------------------------------------- - 75 LITERATURE CONSULTED ~ ----------------------------------------------------------- 76 -5lUTRODUCTION Earthquakes have a ttra c te d universal atten tio n from the e a rlie s t times, and cm account of th e ir destructive power i t Is not surprising th a t they used to be regarded as supernatural phenomena. Among the e a rlie s t existing records of earthquakes are those mentioned in the Bible. Also the w ritings of Serodotua, Pliny, Livy, e t c ., show the In terest which earthquakes a ttra cte d In early ages. Speaking generally, i t may be said th a t the w ritings of the ancients, and those of the Middle Ages, down to the commencement of the Nineteenth Century, tended to the propagation of superstition and to the theories based on speculations with few and imperfect facts fo r th e ir foundation. The development of the study of earthquakes on a ratio n al basis may be regarded as dating from the Nineteenth Century. The science of seismology named from the Greek celsmos, an earth­ quake, and logos, a discourse. In i t s simplest form means the study of earthquakes, but i t now embraces the study of other earth movements due to a variety of causes. The English word earthquake, the German erdbeden, the French tremble meat de te rr a , the Spanish terremoto, the Japanese jish ln , e tc ., a l l mean "earth shaking" when lite r a lly tran slated . The source from which the earthquake originates Is called the "focus," and the region of the surface !m ediately above the focus is termed the "epicentre." The time a t which a shock occurs a t the focus Is referred to as the "time of origin" of the earthquake. -6 - llaers are enormous varlatioaoe in the areas cnrer which earthquakes are perceptible and in the destructive effects which acecepany the shocks. At one end of the scale are the great earthquakes f e l t over hundreds of thousands of square miles# and accompanied by great loss of lif e and extensive damage to property; a t the other are the small shocks f e l t only by a few people and over a very lim ited region. With increasing distance from the epicentre the disturbance gets less and le ss and eventually la imperceptible. The movements recorded by Instruments a t great distances beyond the area in which the earthquake can be f e l t are said to be teleseism ic. The earth is very nearly spherical and so the distance from an earthquake to any place may be measured as an arc of a great c irc le . The study of earthquakes is a branch of the modem science of geophysics, which, as i t s name implies, covers a l l the phenomena of the physics of the earth . The seismologist is interested chiefly in the development of instruments fo r recording earthquakes, and in obtaining from the study of the records a l l the information he can about the earthquakes and about the m aterials inside the earth . Seismology in v ites the cooperation of workers and thinkers in almost every department of science. Mathematicians are faced with many problems relatin g to the e la s tic ity of so lid s, the wave motion propa­ gated from a disturbance, and the response Cf the instruments to applied o scillatio n s of prescribed forms. -7 - Turoing to the more p ractica l side of seismology, the greatest need has been to increase our knowledge of earthquakes so th a t we can lessen the destruction caused by them. For th is purpose i t is necessary to examine the effects of earthquakes upon buildings and the methods which should be adopted to avoid damage to the structures in earthquake-shaken countries. Here we face problems which demand the a tten tio n of engi­ neers, a rc h ite c ts, and b u ild ers, (hi the engineering side there are problems connected with the location and best methods of construction to be adopted fo r houses, facto rie s, bridges, vaterm.ins, e tc . The re su lts obtained from observations of earthquake damage are u tiliz e d by the engineer in designing the buildings to be erected in seismic regions. Seiaaologlcal information is necessary when insurance companies are requested to cover property against earthquake damage. Earthquakes are of more common occurrence than most people realize, and no one place in the world is much more susceptible to them than others. According to Captain N. H. Beck, the world experiences one major earthquake every six and one-half days, and Japan has experienced as many as ten thousand tremors in one year. Eecorda of the United States Coast and Geodetic Department shew th at in the year 1933, twenty-two sta te s had a t le ast one quake that was of moderate or greater in ten sity . Some of the states reported several, notably C alifornia, which in addition to the severe Long Beach earth­ quake reported almost f i f t y other fa irly strong tremors. Washingtcxx follow with seven each. Montana and -8 - CAUSES OF EARTBQUAKES The originating or ultimate causes of earthquakes have been the subjects of controversy fo r more than a century. During the f i r s t h alf of the Nineteenth century these might be divided into three groups: (a) Those which attrib u ted earthquakes to sudden downthrows or collapses of the ground. (b) Those which a ttrib u ted them to volcanic action. (c) Those which attrib u ted them to the action of a liquid in te rio r of the earth upon an external rocky crust under the disturbing influence of tid a l forces. The b e lie f th a t earthquakes were associated with volcanic action, th a t they were caused by i t , or were in earns way dependent upon i t , is as old as A risto tle . I t appears in the works of Pliny, Strabo, and #1 Baueaniae, and was universal throughout the Middle Ages. The repeated destruction of c itie s a t the base of Mt. Aetna, the te rrib le quakes in Hawaii which immediately preceded the eruption of 1868, the calamity of Casamlcciola on the island Pachia in 1883» were a l l associated with volcanos in such a way as to leave no doubt th a t the kinetic cause of them was volcanic in i t s nature. Tbe downthrow, or downfall, or Einsturztheorie has had fo r i t s advocates J . J . Scheuchzer, Swiss geologist; Bousaingault, n a tu ra list; ( numbers re fe r to lis te d lite ra tu re cited.') -9 - AIbert Neckser, and G. H. Otto Volger. These authors were disposed to give the larg est possible extension to the downfall theory. Such down­ throws, Instantly followed by great and far-reaching earthquakes, had been witnessed and v erified in the calam ities of Port Boyal In Jamaica, 1692, In the te rrib le Calabrian quake of 1783# In the Hew Madrid disaster, 1811-12, in the Bern of dutch near the mouth of the Indus, 1819, and in Murcia in 1829. I t remains to glance a t the tid a l theory b rie fly . That the forces exerted upon the earth by the moon, and th e ir variations through the differen t parts of her o rb it, rai^ht, among other re su lts, be effective in promoting earthquakes Is an old idea. I t was f i r s t supported by Alexis Pterrey of Dijon. Perrey' s view was the prevalent b e lie f th a t the e a rth 's In terio r is In a sta te of fusion by reason of aboriginal heat. Upon th is liquid mass, enclosed by a th in , rocky cru st, or skin, the tid a l action of the moon continually exercised a disturbance which reacted upon the crust so as to produce cracks, fissu re s, and displacements, with earthquakes as accompaniments. As the re su lt of th is study, Perrey announced three lavs which are s t i l l known as Perrey's laws. I. Earthquakes are more frequent a t the syzygles, e ith e r of the points a t which the moon Is most nearly in a lin e with the earth and sun, and lass frequent a t the quadratures. H. They become more frequent as the moon approaches perigee and lass frequent as I t approaches apogee, th a t point in the -1 0 - o rb it of the moon which is fa rth e st from the earth, approximately 253,000 milea. III. They are more frequent when the moon is near the meridian than when i t is 90 degrees from I t . Two other modes of earth stre ss have been discussed which are of in te re st in th is connection. The f i r s t is the secular cooling of the e a rth ’s in te rio r and the slow, continuous readjustment of the cold, outer crust to the shrinking nucleus. This view has received a remark­ able development a t the hands of Dr. Robert Mallet in 1871. The other hypothesis originating from Babbage and HerscheI , which takes account of the ultim ate effects of th a t process which has been going cm through­ out the whole range of geological time, in which the m aterials derived from the disintegration of the rocks on the land are carried down by riv ers to the sea or into the valleys and deposited there. IM s involves a sh iftin g of loads from one p art of the e a rth ’s surface to others, and as i t is cumulative through the geological ages i t must generate cumulative stra in s. Professor George Darwin has discussed the subject of earth strain s arisin g from unequal d istrib u tio n of loads upon the surface in a pro­ found and remarkable analysis published in the Proceedings of the Royal Society in 1881. The tran sfer of sediments is the only obvious and p lain ly v isib le cause which has thus fa r been suggested as the source of those cumulative stresses which ultim ately become re s is tle s s and lead to the collapse -1 1 - vhlch generates the earthquake. A very new theory also sta te s th a t water leaking through, the leaks around the ocean bottoms cam In contact with hot rock, change to steam which released with explosive impact causes a trembler in the earth . Forces added to the causes of earthquakes may be: (a) The lin e up of planets. (b) Heavy rain s. (c) Changes In a i r pressure. (d) The melting of polar ice. (e) The sun spots. The Helena quakes occurred in a very dry season, sun spots, low barometric pressure and water level unusually Iow .^ -1 2 #3 EAETa^UAKE WAVES Hot a l l descriptions of tiie phenomena experienced during an earthquake agree, but the general sensation seems to he th a t a major shock consists of three phases. %e f i r s t phase is a trembling, or a series of l l g i t shocks, lastin g momentarily, and building up to the second phase which seems to be a violent wave motion, sometimes up and down, sometimes more of a swaying, and often a combination of both. This la s ts a few seconds and merges in to the fin a l phase, which is a period of lesw ning trembling th a t gradually dies out a f te r a few more seconds. Usually separate p light tremors follow a t short Intervals. A roaring sound always accompanies th is type of earthquakes. The f i r s t waves are fa s te r than the destructive waves, and are f e l t before the severe motion begins unless the observer is near the epicenter. The creaking of buildings, breaking of window panes, fa llin g of chimneys and brick veneer, crashing of dishea fe llin g from shelves, and other sim ilar noises often drown out much of the actual rush lin g of the treatolor I ts e l f . Quite generally the major quake corns without any warning. Usually the v e rtic a l motion is only an inch or two in the very severest quakes, and the horizontal motion a l i t t l e more. I t is the suddenness of a very slig h t motion which causes chimneys to topple and walls to crack. These waves, traveling thrombi the immovable matter of the earth, become damaging when they strik e the movable objects on the surface. The v e rtic a l motion is the strongest over the epicenter, since the rock movemsnt is occurring d irec tly below th is p oint. Farther from the 13- epicenter, as a general ru le , the horizontal movement is more marked than the v e rtic a l motion. The wave motion trav els a t d ifferen t speeds through d ifferen t types of rocks. Passing of waves from one type of rock to another resu lts in a reflec tio n of the wave. Beflection of waves also occurs a t fa u lts . Tremor vibrations tra v e l through the e a rth 's cru st a t a speed of almost three hundred miles a minute. This refers to the ground wave of the quakes the surface waves tra v e l considerably slower. Their velocity has been calculated to be about 1.85 miles per second. Fourier has shown th a t whatever the nature of the i n i t i a l motion, i t can be expressed as the resu ltan t of a number of simple harmonic motions. Again, th a t every wave tr a in , of whatever form, can be expressed, in general, as the resu ltan t of a number of simple harmonic wave tra in s . Destructive earthquakes may la s t fo r several minutes. They may cease and recur. The most destructive p a rt of a major earthquake, however, occurs early and la s ts only a short time, so th a t the fate of any structure is usually decided within the f i r s t minute from the beginning. The in ten sity of shocks of an earthquake varies with the distance of the point of observation f rom the origin of the disturbance, character of the intervening te rra in , e tc . When earthquakes occur, the e ffe c t on a l l structures th a t ris e above the ground is as i f they had been gripped a t th e ir bases by gigantic farces which whip them forward and back, to and fro , end to a certain extent up and down. I f the period and movement of the earthquake waves have been measured, the equivalent force may be determined as follows: -1 5 - 3C J) Frs : I S i IrVi^Ie HarmonTc Ho+Ton Lef , T - fenod Jl= Wave LengfK 9 = ReiahelAfion j= ITs Wave Veloc.i4y ; " j= j= W= r Sin ^ f r e f a r d a f io n * 2 tt iL di s f mi ce i-s j6 - - - fhe, Xace T r'ivn a)t 3 ahda^TO^ * 2TT -Ss- J h* 5 in L n)L - © J s r s 1y) ^ 2 TT i . - 2 tt ^ r sir, 2 i r ( t - | ) f>vd* , Cre^ot-C. JJ= If-T = r s in &ZT ^ t - * j Tak i'tij partial cle.rivo-4ive5 o-f wlfh T^jjveci* t a ,t % % V • r &Z COj T * * * -r is > i n T «m f t - 21 \ ^ ir / iff C i - i ) -^Oh K n*.*. a c c c /e r e t t r o K i ^ Son (^"t ~ ^ b e etjAal t o :. a » ^ r 4ff2, Tl ^vkfche. r - <1m ^ If4vd-e, • ol Ftoyy "T - ^ t t mToel NZevuf-Oh^ ZaM : Zr = a lso «- 8 mo/ M <L 4 TT** Tl iVav*. i Tn* ACC^, lehatToh Tkete^t CT . 4 T V ___ W | -17' An earthquake producing a dynamic e ffe c t in a horizontal direction equal to about l/lO of the weight of structures is a severe earthquake, and m y be assuaad as the ty p ical case fa r which provision should be made in design. Since the v e rtic a l movements are rela tiv e ly small, and since structures are designed to r e s is t v e rtic a l loads, the v e rtic a l earth­ quake movement produces l i t t l e . I f any, damage. P ractically a l l damage is produced by the horizontal action. The movements of the ground, recorded by seismographs, are traveling in various directions when they reach the Instruments. The motion may 1» regarded as composed of the component displacements along three axis a t rig h t angles to each other; the directions usually chosen fo r these axis are to the north, to the e a st, and v e rtic a lly upwards. The equipment fo r completely recording the earth displacements is therefore two seismo­ graphs fo r the horizontal components and one fo r the v e rtic a l. I t is much more d if fic u lt to obtain satisfacto ry records of the motion in the v e rtic a l than in the horizontal directions and many of the seisaological observatories have no v e rtic a l seismograph. Ths horizontal forces produced by some of the disastrous earth­ quakes^ per Mp of the weight of the structure is: Sen Francisco, 1906: F = W X a . 1000 X 6 . 18? lb . per kip g 3 2 .2 Tokyo# 1923: F • 1000 X 10 . 310 lb . per kip 3 2 .2 ToiMbsaR, 1923: T = IOOO X IU = 438 lb . per Mp "32.2 Kamkura, 1923: F . 1000 X IS ■ 563 lb . per kip 32.2 19- IRTESTICaTIOH OF EAHFlEiUAKE Si WtdnftW IR A BUILDING IBAIE As an exastple, a ty p ical reinforced concrete building frame Is to be ln rsstig sted fo r the seismic forces specified by the Los Angeles City Building Code and the Gbiforo R iilding Code. A typical beam and a column otf th a t frame are to be designed according to the Los Angeles City Building Code, and the Uniform Building Code Specifications, and a com­ parison made between the two designs. Kexfc, the footings are to be investigated fo r the seismic forces specified by the Loe Angeles City Building Code and the Uniform Building Code, arranged and designed so th a t they can r e s is t any horizontal displacement caused by the calculated horizontal forces. 20- Fig. 2 Front Elevation of the building frame investigated -2 1 - S 'd -JLO- Flg. 3 Plan of building Investigated. 22 Coaputatlons of the momenta produced by the v e rtic a l loads on the roof of the frame lmreatigatedg D.L. 4 L.L. Zo' cZ 2/ 7 D.L. i L«L« /3 T /O D.L» 4 L.L. Dead load from slab: W1 = 2 Q x l x £ x 150 = 1500 " " " snow: " ” " girder: W2 = 20 x 25 = 500 2b . per f t . W, - 10 x 14 x 150 = 146 lb . per f t . Total * 2,146 F. S. M. of roof girders: FEMc_2 > 2.146 x 20 x 20 « 72 k - ft. 12 FEMo_-s . 3 2.146 x 10 x 10 12 2b . per f t . = 17.9 k - f t. Mps per f t . 23- Pob. Maolfl -62.8 - vL2 - 2.146 1/3___ W 18 - 9 9 - 4.5 2.9 - 1.9 .9 - .k •3 1/3/1/3 -l8 72 — 18 -18 9 18 - 9 - 9 4.9 2.3 - 2.9 - 2.9 1.9 1.2 - .9 - .9 .4 .4 - *3 - *3 __i/ -72 36 - 9 4.9 - 4.5 2.3 - 1.9 .8 - .4 .2 /33.7 -33.7 /62.8 -43.6 8 8 A 3.6 _______ 1 /3 / -72 18 -18 9 —2.3 2.9 - 1.2 .9 - .4 •3 U /h 72 -36 9 - 4.5 4.5 - 2.3 1.9 - .8 .4 • *2 H S M Fm Piw. Maa.fl fl = vL2 - 2.146 x 10 x 10 r G-3 - 5- ’ ----------- 107 k - f t. 26.8 k - ft. +3+ -2 4 - F ig. U Moment diagram fo r roof girders and columns of the frame in v esti­ gated along column lin e . (Moments expressed in K -ft.) -2 5 - Cceputationa for oomante d istrib u tio n fo r the f i f t h flo o r of the from lm restlgated: Live Load = 40 x 20 z 800 Xb/ft. Slab Dead Load = 150 x 20 x I Z 1500 Girder Dead Load m 10 x 14 x 150 Z 146 e 600 144 (#50 of) Brick P artitio n s 10 x 60 X Total 3.046 k/ffc. ™ D .L. = ^ esbW = ll Pos- mooDlM »S*L = = 2.246 x 20 x 20 s 75 k-ffc. 3.01*6 x 20 x 20 r 102 k-ffc. 3.046 x 20 x 20 S - 152 k - f t. 2.24 x 20 x 20 s 112 k - f t . 12 12 = B FQ^ 1 Middle Span = 2.246 x 10 x 10 12 = I S .5 k - f t . Pos. Moante - 28 k - f t . = 2.246 x 10 x 10 8 LL s 0.8 k/ffc; DL = 2.246 k /ft / ________DL/LL _______ / DL______ / 102 - 34 10 - 3 3 - I - 17 -10 7 7 - 2 - 3 I I /7 7 -92/35 -102 21 19 21 -19 102 -21 - 21 10 I? - 7 - 7 3 2 ______ -102 34 - 10 1 - 1 MWW m SL/LL -35 / 92 77 - / -2 6 — Pig. 9 coliairos and girders of the frame investigated along column lin e . - / FKM 102 - 34 10 - 3 3 - I DL/LL TTi L_ FEM 75 -25 6 - 2 3 - I /56 DL 27 - / DL/LL -102 25 -25 75 -12 -12 19 19 10 13 - 17 - 6 6 6 - 6 - 6 - I - 3 I 3 I I - I - I T l * /42 /70 DL / DL/LL 1_ -7 5 25 -25 75 13 13 -13 -13 6 13 -13 - 6 5 5 - 5 - 5 - I - 3 I 3 I I - I - I -70 /35 -35 /70 DL -75 25 - 6 2 - 3 I ^56 -75 25 - 6 2 3 - I -56 ./ / -2 8 - Q K) f ig . 6 Mcment diagram fo r the 5th floor columns and girders of the frame Investigated along column line fo r max. neg. mom. (Moments expressed In K -ft.) -2 9 - Fig. 7 Moment diagram of the 5th floor columns and girders of the frame Investigated along column lin e fo r max. pos. am . (Moments expressed In K-f t . ) -3 0 - Dealgn of the F ir s t Floor Celling Beam - K-K3 KU 2. 0 ' Load P la a d ire c t load from the colam above. D etondnstlon of Pt Boof Leads ” U girders 35 x 150 z IU % 10 IUU 5 ,1 0 0 enow 25 x 15 x 20 = slab I x 20 x 12 x 150 = 22.500 35,100 lb . 10 x 12 10 x 150 12 x 12 * = 1 ,2 5 0 four girders = 5 ,io o slab s 22,500 liv e load s 12,000 p artitio n s * 21,000 Fcwnrth Floor Loads column above 7,500 61,850 lb . For the r e s t three flo o rs the flo o r, therefore weight is added fo r each individual 61,850 x 3 ■ 185,550 lb . So to ta l load P equals to . 35,100 / 61,850 / 185,550 . 282,500 lb s. -31- ^262k Dead Load plus Live Load ! DL 7 7 A I B C Fig. 7<*Loading fo r the second flo o r. vDL . 2.246 k /f t. = 0.8 k /f t. r a ^AB = Due to the dead load = 2.246 x 30 x 30 - 168 k - ft 12 Due to the liv e load = 0.8 x 30 z 30 12 Due to d irect load. z P x 20 ac IO2 30 x 30 ^BA = z 630 k -ft 282 x 10 x 20* z 1200 k -ft 30 x 30 FEM due to the dead load in span B C: FEH = 2.246 x 20 x 20 - 75 k -ft 12 therefore. Total FEHto " = 168 / 60 / 630 * / 858 k -ft FEMba = 168 / 60 / 1200 = -1428 k -ft r 60 k -ft -3 2 - D irect L. / L.L. / D.L. 858 -290 -170 56 17 - 6 0 - m -1428 340 - 145 33 28 0 - 3 ril7 5 D.L. T m 75 340 13 33 - 28 0 - 3 7530 -75 25 170 -56 17 - 6 0 "775 DlfGGt L* / D> I**____________D*L» / L»L* Z EBH 798 -266 158 - 52 15 - 5 6 - 2 /652 -1368 316 - 133 29 - 26 13 3 ___ I -1171 102 316 17 29 - 26 13 - 3 I M9 -102 34 158 - 52 15 - 5 6 - 2 / 52 7 -33- 7 Io' Z A Poe. Mon. AB * B a o ' BL / LL / Cone. Load KU™ = Pab = 282 x 10 x 20 = i860 k -ft L 35 %j, V DL r 2£$ (I-*) 2 z 3«Q^6 x 10 ( 30-10) = 304.0 2 Total Poa. Mon. s 2184 k - ft Pos. Mon. In span BC Mpoa. = 3.046 x^20 x 20 - 152 k -ft Pos. Mon. In span BC when loaded only with dead load a Mpoe - 2.246 x 20 x 20 = 112 k -ft 8 I C -34- Plg. 8 Moaent diagram of the 2nd flo o r columns end girders along the column lin e of the frame investigated, by loading the l e f t span AS. (Moments expressed In K-f t . ) -35- Pig. 9 Mooant diagram of the 2nd flo o r columns and girders along the column lin e of the frame investigated, by loading the rig h t span BC. (Moments expressed in K -ft.) -36- Deteralnation of the horizontal wind shears fo r every story of the fle a s investigated. Wind pressure i s taken as 15 lb s. per sq. f t . fo r every portion of the structure. (L. A. Building Code). Siear in the 5th floor Siear in the 4th flo o r - ------------ ----- -------— 1.5 / 3 s 4.5 kips Shear in the 3rd flo o r z 7-5 kips Shear in the 2nd flo o r - —_______— - 3 y 1.5 / 3 / 3 Shear in the 1st flo o r = -------- 3 / 1.5 / 3 / 3 / 3.75 = 14.3 kips s 10.5 kips Computation of the wind forces in every individual flo o r. 5th flo o r: 20 x 5 x 15 = 1.5 kips 4th flo o r: 20 x 10 x 15 r 3 kips 3rd flo o r: " r 3 kips 2nd flo o r: * - 3 kips 1s t flo o r: 20 x 12.5 x 15 s 3.75 kips -37- Determination of the horizontal seismic forces produced on the frame investigated by the horizontal force formula given by the Lot Angeles City Building Code. T 2 Ha a = N/ 60 4.5 where. T 2 Horizontal seismic force a 2 Acceleration N 2 Hunber of sto rie s above the story under consideration 5th Floor J = E g * 2.146 x 50 x 1000 2 (slab / snow / girders) = 107,500 W2 * I x I x 10 x 150 x 4 » (columns) 8 6,000 V3 « 600 x (50 2 (p artitio n s) - 78,000 2 191, 500# S 191,500# 8 123,000 S 78,000 * 6,000 2 398,500 *1 = / 80) Wt O t Fh = 191,500 60 32.2 * 1 / 4 . 5 2 65,000# 4th Floor wI (from 5th floor) W2 (L. L. / D. L.) a 2,446 x 50 w3 (p artitio n s) W* (columns) -38 - K. = 398,500 _ 60 32.2 4.5 / 2 S 115, 000# W1 (from 5th floor) S 191, 500# W2 (from 4th floor) S 207,000 Wg (from 3rd floor) Z 207,000 3rd Floor 605,500 Fh : 605,500 60 32.2 x 4 . 5 / 3 z 150, 000# 2nd Floor W1 (from floo rs above) Z 605,000 W2 (from second floor) Z 207,000 812,000 F1, r 812,000 , 32.2 , 60 4.5 / 4 = 180, 000# 1st Floor W1 (veight of floors above) : K = 812,000 _ 60 32.2 X 4.5 / 5 = 812, 000# 159,000# 39- Determlntttioa of the horizontal seismic forces produced on the frame investigated by the horizontal force formula given by the TMfcnta Building Code. Horizontal force formula: F = CW W z Total dead load plus one-half liv e load C = Horizontal force facto r Montana belongs to section 2 of the earthquake sections and the C constant equals to 0.02 x 2 - 0.04 Confutation of Horizontal Seismic Force a t 5th Floor F = CW (slab and snow) = I x I x 10 x 150 x 4 (columns) S 6,000 600 x 130 (p artitio n s) S 78,000 * to t a 191,000 *1 = 2,146 x 50 it Wg a *h = 191,000 x 0.04 S 107,000 7,600# 4th Floor 191,000 W1 (from 5th floor) V2 (£ live load) e 800 x 50 2 = w3 (dead load) = 1646 x 50 Z 82,000 »4 (p artitio n s) Z 78,000 W5 (4 columns) = 6,000 = 377,000 4 ft Wto t = 37’,000 x 0.04 = 20,000 15, 000# 3rd Floor M1 ( v e t f r o m flo o rs above) = 377,000# Wg (weIgJit from 3rd floor) = 186,000 Wto t = 563,000 z Fh = 563,000 x 0.04 22,500# 2nd Floor (from floors above) Wg (from 2nd floor) wt c t = 563,000 s 186,000 « 749,000 = Fh % 749,000 x 0.04 30, 000# 1st Floor Wi (from floors above) = 749,000 x 0.04 s 749,000 30,000# -41- <?SO—-*■ Fig* 10 Wind Bcoants produced on the 5th flo o r. (All momenta are expressed In Klp-f t .) VI x 25 / V2 x 5 - V3 x 5 - V4 X 25 vI Z z 1,500 x 5 = 7,500 5 V2 z -5 V3 3*2 x 25 / V2 x 5 / 5V2 / 5V2 x 25 = 7,500 V2 (5 x 25 / 5 / 5 / 5 x 25) = 7,500 V2 s 7^0 0 s 29 lb s. V3 B -29 lb s. V1 : V4 s 145 x X 145 Ibe. 1,250 I -145 lbs 2 1,250 s 8.7 f t . (distance from le f t 3$5 corner of neutral p t.) -42- 015* F ig . H Hind Momentc produced m the 4th flo o r. (AU moments are expressed in K ip -ft.) 750 x 5 s 3 ,7 5 0 l b . - f t . V1 = 87 x 5 = 435 Ibe. Vg = 87 lb s. 5,ooo : 435% X - 5,000 = 11.5 f t . (p t. of 435 contraflaxure) -43- Fig. 12 Wind Momenta on the 3rd flo o r. (All momenta are expressed in K -ft.) 1,250 x 5 r 6,250 f t . lb s. V2 » 37^500 s 144 lb s. 720 x X ; V1 « 144 x 5 = 720 lb s. 10,000 X = 10,000 z 720 13*9 f t . (d ie. of p t. of ccxatraflexure from 1f t . corner) -44- Fig. 13 Wind Moaente on the 2nd flo o r. (All BMBante are expressed In K -ft.) 1,750 x 5 r 8,750 f t . -Ib e. V5, = 52,500 = 202 lb . 260 * V1 = 1,010 lb -40 Pig. 14 Wind Momenta on the l e t flo o r, (Momenta are expressed In K -ft.) -46- +JOB Ti g. 15 Earthquake am ents on the 5th flo o r with the L. A. Building Code requirements. (Moments expressed in K -ft.) -U t - Flg. 16 EartbqpiakB Boaeats an the Uth flo o r with the L. A. BulMlng Codte requirements. (Noeeats expressed la K -ft.) -48-220 * 2 SO -220 »250 T ie- 17 Earthquake oonente on the 3rd flo o r with the L. A. Building Code requirements. (Hoaents are expressed in K -ft.) — + ISO * -Z75- 3oo Fig. 18 Earthquake moments on the 2nd flo o r with the L. A. Building Code requirements. (Moments expressed in K-ffc.) +/S0 1 -5 4 7 f ig . 19 EarttiquakB xaooBirfcB on the 1 st flo o r with the L. A. Building Code requirements. (Moments expressed in K -ft.) -51- Fig. 20 EarthqualBe moments oa the 5th flo o r with the Uhlfona Building Code requirements. (Moments expressed in K -ft.) -52- Fig. 21 EarthquakB aoments on the 4th flo o r with the Untfora Building Code requirements. (Momente expressed in K- f t .) -53Ad to ♦ 36 4 38 Fig. 22 Earthquake moments an the 3rd flo o r with the Uniform Building Code requirements. (Moments expressed in K -ft.) tVu -54- +*2 5 * 5** h Fig. 23 Earthquake acsaente cm tibe 2nd flo o r with the Hnifora Building Code requirements. (Moments expressed in K -ft.) f ig . 2k Earthciuake moments on the l e t flo o r with the Uniform BuiMing Code requirements. (Mmaente expressed in K-f t . ) -56- As an esmsple, the beam H2 of the frame Investigated is to be designed according to the requirements of the Uniform Building Code and Los Angeles City Building Code, respectively. Design of the beam H-2 by the Uniform Building Code requirements. D.L. - L.L. ( le f t end) = - T l k - ft Wind forces * - 10 k - ft - Earthquake forces - - 32 k -ft - 11.0 k -ft -109.4 k -ft Bight end = - 94.0 k - ft -119 k -ft Max. Left End Moment = -119 k -ft Max. Bight m Max. Poe. Mom. n z -109.4 k - ft - - 68 k -ft M z 119 x 12 x 1000 Z 1,430,000 lb . in . I 1,430.000 _ 23 in . d z 1 220 x 12 y As = 1.430,000 x 8 - 4.4 sq. in . 16,000 x 23 x? Section z 12" x 25" As « 4.4 sq. in 4.4 k - ft -57’ Design of the bean H-2 by the Los Angeles City Building Code requlrea sats. D.L. / L.L. ( le f t end) z rig h t end - - 77 k -ft - 94 k -ft Wind Momenta z - 10 k - ft ft " - - 4.4 k -ft Earthquake Momenta - M n w - 70 -168.4 k -ft Max. Left End Momenta Z -307 k -ft Max. Bight End Momenta Z -168.4 k -ft Max. - / 68 k -ft Fo b . Mom. -220 -307 k - ft M s 307 x 12 x 1000 = 3,700,000 lb . in . d Ag : ( 3.700,000 V7* z 220 x / 3,700,000 x 8 15,000 x 7 x 32 32 in . 8.3 eq. in . Section * 16H x 34" Aa = 8.3 in .2 -58- Dealgn of the column G2-S2 D irect Load P on Column: Eoof Loads = 5th Floor = 61.8 4th Floor s Total P 35*1 6 l,8 = 158.7 kips E ccentricity produced by D.L. / L.L. = 94-42 z - 52 k -ft Wind Moments z / 12.5 Earthquake Moments (L.A. Building Cods) z /250.0 Earthquake Moments (Uniform Building Code) z / 38.0 Design of the Column G2-H2 with the Unlfwm Building Code requirements. P z 159 kips; E z 1*5 k - ft fg S 16,000 psi f c = 1,200 psi n z 10 B z 220 k z 0.4 -59- Gross Area = 100 sq. In. Try section IOn x MT Aa z 3; 100 x 0 .0 1 Transfer Ae = (n-l)Ae = (1 0 -1 )3 I Area Total f. - 1 /1 2 x 10 < 3 < 0 .0 * X 100 : x 103 / 2 x1 3 .5 x3s s 835 / 2*3 r 1078 = 100 / 27 = 12? - 1500 x 12 x 5 1073 159.000 i 127 1250 2? or 1 3 .5 fear each aide £ 8* f B m 133* x 10 = 13,3*0 < 16,000 O.K. Section : 12" x 12" Ag s 3 eq. in . -60Deslgn of the column Q2-E2 with the L. A. Building Code requirements P r 159 K E s 210 K -ft 20" x 20" Try Section Area gross = ^OO eq. in . Ag = 12 eq. in . UOO x 0.01 < 12 < UOO x 0.0U Transfer A8 % (n-l)Aa s 9 x 12 * 108 eq. in . Total A s I - UOO / 108 = 508 aq. in . 1/12 x 20 x 203 / 2 x 5U x Q2 s 13,300 / 6,900 s 20,200 tC _ 159.000_/ 210,000 x 10 x 12 *503 20,200 3lUjf 1250 fg 5 155U x 10 s 15,5UO < 16,000 O.K. Section s 20" x 20" A8 r 12 sq. In. - 6 l- Design of fo o tin g under the columns KLt KgL8 KkL of the fr*™* investigated. Total load on column KL Load from the roof - 21.46 K ” " 5th flo o r = 30.46 ” " 4th " " - 21.46 K - *9 = 28.94 ” = 30.46 - %10 = 27.4? " 3rd " = 30.46 25.86 " 2nd H = 30.46 - $20 : Total load on column KL - - ^15 = 24.36 128.09 Kips 129 Kipe Plus the to ta l load carried by column 82 which is 240 Klps and is divided between columns KL and K3L is in such proportion: £40* 7*L rR„ 20' 240 z 10 = Bl x 30; sL = 240 x 10 30 % S 240 - 80 s 160 Kipe Therefore, Total load on column KL : 129/80 S 209 Kips Total load on column K3L * 276 / 160 m 436 Kips Total load on column K4L s 329 S 80 Kips 129 Kips — 62— I t ie suggested th a t i t Is more economical to design the column footings separately and then connect them against earthquake displace­ ments by means of teams which are to be poured oonolithically with the footings rath er than to build a continuous footing under the columns of the frame investigated. Design of a footing under the column KL F = 209 Kipe A - 1.6 f t . x 1.6 f t . S oil pressure s 4,000 lb . per sq. f t . Total load = 209,000 lb s. Footing 566 = 12,000 Total Load = 221,000 lb s. Area required Btet pressure = 221,000 = 55 sq. f t . "4,000 • 209 * 3.8 Kips per sq. f t . Therefore, Footing area z 7*4 f t . x 7.4 f t . Column area * 1.6 f t . x 1.6 f t . Moments about face of column: H s 1.6 x 2.9 x 2 ^ x 38OO / 2 (2.9 x £ x 2.9 x 38OO x 2/3 x 2.9) 2 25,500 / 61,600 : 87,100 r t .- i b s . = -63- Asetzme b ■= a / d * 1.6 / 1.5 * Absuhb d = 1.5 f t . d s f t . or 37 in . » 12 in . (M / Sbfi = TJee 18 in . Check ▼ 7' « 209.000 x (18 / 18 / 19) (18 / 18 / 19) 7.4 x t .4 %IAt = - V = 209,000 - 80.000 T = 32.200 x 8 = 40 7 x 55 x 18 A. m 8o' oo° = 129.000 = 32,200 O2K. M = 97 ,000 x 12 x 8 = 4.6 eq. in . f 8jd 16,000 x 7 x l8 Anchor a l l s te e l fo r bond -6U- Dealga of the footing under column KgL P = U36,000 lb s. A % 1.7 f t . x 1.7 f t . S oil pressure = 4,000 lb s. per f t . aq. Total load = 436,000 Footing *6 s 25,000 Total = 461,000 lb s. Area required = 461,000 * 115 f t.- s q . 4,000 Het pressure = 436 = 3.8 Klps per sq. f t . 115 Footing area = 10.7 f t . x 10.7 f t . ColtaBi area = 1 .7 f t . x 1 .7 f t . M « 1.7 x 4.5 x 4.5 x 3800 / 2(4.5 x 4.5 x 3,800 x 2/3 x 4.5) 2 • 2 65,000 / 230,000 s 295,000 f t . -Ib e. Asexnae b = a / d = 1.7 / 1.7 x 3.4 f t Take d * 1.7 f t . Use d s 24 in * -65- Check v V* « 436,000 x (19»8 j 19.8 / 17A) (19.8 4 19.8 4 17.4) 10.7 sc 10,7 at IW - 436,000 x 57.1 x 57.1 = 86,500 10.7 x 10.7 x IW V z 436,000 - 86,500 T™ T a 87,000 x 8 7 x 57.1 % 2% Ae - 349^500 z 87,000 a 72 295.000 x 12 x 8 : 7 x 16,000 x 24 O.K. 10.5 eq. In. Anchor a l l ste e l fo r bond -66- Design of a footing under tbs column HkL P % 129,000 lb s. A s 1.5 f t . x 1.5 f t . S oil Pressure = 4,000 lb s. per sq. f t . D irect Load % 129,000 lb s. $6 Footing r Total 8,000 = 137,000 lb s. Area required - 137,000 : 4,000 34.2 sq. f t . Set Pressure - 129 34.2 3*8 Kips per sq. f t . z Footing Area * 5.85 f t . x 5.85 f t . Column Area = 1.5 f t . x 1.5 f t . Moments about the face of the column M = 1.5 x 2.17 x 2 0 7 x 3800 / 2 (2.17 x 2 0 7 x 3800 x 2/3 x 20 7 ) *2 - d z 13,500 / 25,800 2 S 39,000 f t .- l b s . Assume b % a / d % 1.5 / 1.0 - 2.5 f t . Assume d = I ft. (M /Kbf Z ( I k v g V f-Ig f ; ( 7 ll5 Ze = 8^ 5 1 n Take d S 10 in . 129,000 x (1 0 / 10 / 18) (10 / 10 ^ 18) 5.85 z 5-05 x l U 129.000 z 38 x 38 5.85 x 5.85 x 144 37,600 129.000 jj—— - 37.600 = 91^400 = 22,900 22,900 x 8 = 60 38 x 7 x 10 ,000 x 12 x 8 r ,000 x 7 X 10' O.K. 3.4 » i . in . Anchor a l l s t e e l fo r bond -68- Fig. 25 Footings under the columns of the frame investigated. The idea is to ti e the three footings by means of a beam which sh a ll be poured monolithically with the columns and footings. This beam w ill be strong enough to take care of the large compression or tensions which might occur by the horizontal displacements of the footings due to the horizontal seismic forces. i — 69"* Computation of the horizontal seismic forces by the requirements o f the UNIFORM BUILDmi CODE. Procedure: Column KL w* it W z 209,000 Iba. CW C s 0.04 yH = 0.04 x 209,000 % 8,390 lb s. W r 436,000 lb s. W N H Colum K3L 436,000 x 0.04 r 17,900 lb s. Colum K4L W = 129,000 lb s. it •r 129,000 x 0.04 % 9,190 lb s. -70- Design o f a t i e between the footings under the coluana o f the frame investigated fo r the horizontal displacement stated by the UNIFORM HJILDIIiG CODE. Procedure; Max. Tension or Compression between the footin gs; C or T = 17,500 / 8,350 P : Try section = 25,850 lb s. 25,850 8" x 8" Area = 64 sq . in . Try Ag = 1.7 sq. in . 64 x 0.01 < 1.7 < 64 x 0.04 Transfer Area = (n-l)Ag r (10-1)1.7 z 9 x 1.7 = 15.3 eq. in . Total Area = 64 / 15.3 f 25.850 79.3 « P/A . = 79-3 sq. in . 325 p . s . i . f 8 = 325 x 10 = 3,250 < 16,000 0»£. Check s t e e l fo r tension f 8 z P/Aa - 25.850 z 15,250 < 16,000 1.7 Uae section O.K. 8" x 8" A8 % 1*7 sq. in . -71 Computation a t the horizontal seism ic forces by the requirements o f the LOS ABGELES CITi BDHDIHG CODE. Procedure! Coluap KL W = 209,000 lb s. 60 = 41,000 lbs Fg = 209,000 x 32.2 5 f h-5 Colmm K3L V = fo36,000 lb s. r H = fo36,000 x 60 = 85,500 lbs 5 / 4.5 Column XfoL W = 129,000 lb s. 60 : Fg = 129.000 x 32.2 5 / 4.5 25,400 lbs -72- Design of a t i e between the footings under the columns of the frame investigated fo r the horizontal displacement stated by the LCS ANGELES C m BtJILDIKG CQEE. Procedure: Max. Tension or Congiression between the footings: CwT = 89,500 / 41,000 = 126,500 lb s. P - 126,500 lb s. Try section 15" x 15" A % 225 sq. in. Try Ag - 8 sq. in . 225 x 0.01 < 8 < 225 x 0.04 Transfer A = (n-l)Ae Z Total Area f C f , 9x8 = 72 sq. in . 225 / 72 = 297 sq. in . = P/A = 126.500 297 425 p .s .i . - n x f c = 425 x 10 = 4,250 p . s . i . Check s te e l fo r tension f 8 = P/Aa r 126^500 : 15,800 < 16,000 OzK. Use Section 15" x 15" A8 = 8 sq. in . -73- COSCLDSICffl As B r e su lt o f the In veetlgstion o f the "building frame fo r the seismic farces Indicated by the Los Angeles City Building Code and the Uniform Building Code, i t i s concluded, th at the lig h te r the v e r tic a l loads on the building, the smaller the horizontal seismic forces tending to displace the columns of the structure. I f the t i e s between the footin gs are designed so that they can r e s is t the cosnyroaeion or tension which occurs due to the horizontal displacements o f the fo o tin g s, the structure might be considered earthquake r e sis ta n t. However, excess reinforcement o f the columns and girders of the structure i s o f considerable importance. Since the t i e s fo r the footings have only been designed for horizontal ten sion or compression, to prevent any undesirable v e r tic a l displacement, they should be b u ilt so th at they do not come in touch with the earth below. A comparison of the designs made, based on the two codes, shows the difference between the moments on the columns and gird ers, and the horizontal shears on the columns. This difference i s due to the determined horizontal seism ic forces by using the formulas given by the L. A. C ity Building Code and the Ihiiform BuiMing Code. The Loe Angeles C ity Building Code horizontal force formula la based on a large factor of sa fe ty , which considerably a ffe c ts the siz e -7%- of the beans and coluams, and increasee the amount of reinforcing s te e l. Table I Comparison of Sections Uniform Building Codbs Beam size Beam ste e l Column size Column ste e l Loa Angeles City Building Code 12" x 25" UA sq. in . 12" x 22" 3 eq. in . 16” x 34” 8.3 sq. in . 20" x 20" 12 sq. in . d r 18" Ag z 4.6 sq. in. d : 24" A8 - 10.5 eq. in . d s 10” Ag r 3.4 sq. in . Footing Under Colxsan KL 7 .4 ' x 7.4* Footing Under Column K3L 10.7' x 10.7' Footing Under Column K4L 5.85' z 5.85 * Uniform Building Code Los Angeles City Building Code Ties between footings 15" x 15" 1.7 sq. in . 8 sq. in . M CO Tie s te e l CO Tie size 32:9B85BS5BBaS #550) # . ia2G 9aaaa& a, #9» 3 ^ AGlBbBm, %eW&, SWbmp @a&(% ., m&.y 3kKx8m* 3839* 0&. JBBGkKBSMaKt, mBBBM#,* ag. 61, BsWW. %# 3 ba WbmQfWA Ge* <xf BBWa, 1936, # 3 - JkadkSBdRXGkF *%ZRX3BRBL]B8a%99B8BgBg%&»* %* d&» B e W W S y S b e SDBGbggGKB&aBdS ISdSltGBasgr < 8 * o e B O em , I 936 . mmo#, a . ge ocM Bma i m ,* P iib lis h s S "egr B artS aaS Semsat^ A s s e e ia M m s pg» 6 , SGbgk BESlaaae iSosfiaaaeeabaaagBdbaeiiaoBe IaWLfpmtbe ##&o» maaeai m., c a a i IBgMses?^ S a a B le g s jl SalifSE SlB s5t &S3Eica$i S n sM tn ^ s a f 8W&& l3cR8aa3Gaei%L@Bt, aae*, 3385» EBadLtacxBJWemB, Ikmy SBadz. 1938% *%B33@BL IMBBGBBBKKBS,* R eiiiW a IW fliG M ag C *. <d> IBdksaa Bad^pSidant W & s , T88ZKBB&& 3%., C i? H IBasilGOksgKt? (asldbetasaSdi* % A # K# KBB* taamngsBme iBSBBBBgBEGaBSLJ* A sa r lc e A I w t i t a t e c f SHBBd ews%?aG%l<mf 3%#,, 385 iW iso a AwzxAs, IBsa? IW k. ( & e a W 2 , Jbadb J , , 1 9 3 b , *BBBW8S0S^GF]W0gaB8BB3&33aB&9B0e IaBGKBBEES, S W s (kSEBSBZGr, I a e ^ I B e TBMAsaaa 3%*db8i IaeSdbGaL, GbazsSEKBa TBgBazG, 3 # & ? *33BI8EB5B8B%EB8^,* 3 . 3 . SPwSaoaaa aa& S M * , Be®' Yasko . & ce IkogBtlaB ClSgr m i i a i a g Ge8e? 1 9 # m iM Qa& Iksa,, 1939, BssxxgSi SBaa&lea. ^ P. th e %&r#opak& Ekxa a sa #&., 3%%**, C o m lm im , 1908* C8%&]3S8GS33%1 S3BS5S58SB5S3: <Sf A8B3& 3#, 198$** ShabaLtGRBaaLTbgr S&& flasssgaja IasM fete dg lasi*:WM2.? B. Co iSeGdksgr* 8 . i s , , 3889, *SBB35SE3aP*St SBOSKBBb OP GBKBOGE,* Iaaadbs*, O m zSse m®. Co= QBgLakxtae, g& 9* ^ E m B W E D (%35K9S3RSB 3XGE@@B*" JOba TRLlegr a a S t K e e , 3&a«, m m m a B u i m w W a , %&*3j5k;<RKWd: SSKKbatsg OBESoiale* IBQaBszeaeef IdSB mspase, GsMjEtwaBla, IS&O, P ^ t e d 1%% the #. IS. &. MONTANA STATE Untvcdcttv 3 1762 10014966 3 i N378 92611 M34r I cop.2 M arkelllat C. k . Research on earthquake r e sista n t s ^ r u c u i u ’eij . ISSUED TO DATE ' >- ecn NOV7 \ - - ___ ___».-- a/:s W rp ^ r r . . *•. 8 ’62 /V 3 7 S ’ n 3 4 h a- Cop. 2. 9&6 / / I