US2035143A - Earthquake protected building construction - Google Patents

Description

March 24, 1936. G, VA L ER 2,035,143

EARTHQUAKE PROTECTED BUILDING CONSTRUCTION Filed July 29, 1955 s Shets-Sheet 1 Q 'N' w 8% N March 24, 1936. CAVAGUER! 2,035,143

EARTHQUAKE PROTECTEI) BUILDING CONSTRUCTION Filed July 29, 1955 5 Sheets-Sheet 2 March 24, 1936. e, CAYAGLIERI EARTHQUAKE PROTECTED BUILDING CONSTRUCTION Filed July 29, 1935 3 Sheets-Sheet 3 v Patented Mar. 24, 1936 mm STATES EARTHQUAKE PROTECTED BUILDING CONSTRUCTION Giuseppe Cavaglieri, Los Angeles, Calif., assignor to Grace F. Marquis, Los Angeles, Calif.

Application July 29, 1935, Serial No. 33,644

9 Claims.

This invention is directed generally to the provision of earthquake-protected building structures.

The so-called rigid type of building has previously been generally accepted as offering the greatest security against damage from earthquake shocks. However, earthquake movements caused in buildings of the rigid type are often of considerable magnitude and while such buildings as ordinarily constructed may be in no substantial danger of complete collapse from earthquakes even of relatively great severity, the relative bending, shearing and twisting movements set up in their various members frequently result in considerable damage being done to walls, plaster, piping, etc. Moreover, buildings of the rigid type designed to withstand earth shocks are relatively expensive to erect.

It is a general object of the present invention to provide a novel type of building in which movements caused by earthquakes are practically eliminated.

My invention accomplishes this object through the provision of what may be generally described as a flexible horizontal plane or planes between the foundation and the superstructure of the building, the foundation, below this plane, being capable of moving horizontally beneath the superstructure with movement of the earth,

while the superstructure remains nearly stationary in position. The flexible plane between the foundation and the superstructure consists of a series of ball and cup assemblies, which are so arranged as to allow a limited relative hori- 5 zontal movement of the foundation below the superstructure by a rolling action on these balls. The halls are set, top and bottom, on concave bearing surfaces secured to the superstructure and foundation, respectively, so that a quick horizontal movement of the foundation due to an earthquake shock will cause the balls to roll up slightly inclined bearing surfaces, thus slightly lifting the superstructure. If the shock is of a vibratory character, the balls roll back and forth across the concave bearing surfaces, alternately slightly lifting and then lowering the superstructure, and finally settling to the centers of the bearing surfaces upon completion of the earth movements. The rolling action between the foundation and superstructure absorbs a great quantity of the energy of the shock, and the great inertia of the superstructure prevents it from receiving substantial movement as the foundation shifts in horizontal directions with the earthquake. Of course, due to the reaction of the ball supports as the foundation is moved by the earth shock, the building will have some small movement in a direction opposite to that of the earth shock, but this movement will be comparatively small because of the great mam of the building. It is estimated that earth vibrations arising from earthquakes do not measure over from to /8" in amplitude-where the ground is solid, or over approximately one inch in soft or muddy soil. Due to reaction, the building of the present invention may then have an opposing vibratory movement of say A," amplitude, this of course depending upon its mass and inertia. Such a reduction in motion is highlyv beneficial, and reduces the effect of a very severe earthquake to an effect comparable with that experienced in ordinary buildings with very light earth movements.

A further feature of the invention is the provision of a modified contour on the concave surfaces of the ball-supporting cups, designed to prevent the superstructure from moving at increasing amplitude in timed step with the vibratory motion of the earth in the event the period of the earth movement should for a time equal the natural period of vibration of the superstructure. It is of course improbable that the period of vibration of an earthquake would match the natural period of the superstructure, but if such should occur, severe movement of the superstructure might result. I eliminate possibility of such action by forming, the concave bearing surfaces with slight, circular, wave-like depressions, which have the effect of breaking up entirely any tendency of the superstructure to time with vibration of the earth.

The invention will be more fully understood from the following detailed description of a present preferred embodiment thereof, reference for this purpose being had to the accompanying drawings, in which:

Fig. 1 is a horizontal section of a. building showing portions of the present invention;

Fig. 2 is a vertical section taken on line 2-2 of .1;

Fig. 3 is an enlarged view of a portion of Fig. 2;

Fig. 4 is a detail section showing typical flexible pipe connections adapted for the building of the present invention; and

Fig. 5 is a detail section of a. bearing cup having a modified contour;

Fig. 6 is a face view of one of the bearing cups; and

Fig. 7 indicates a flood type of foundation enthe concrete (Fig. 2).

tirely covered semblies.

Fig, 1 is a plan section of an illustrative buildwith I beams ca yin ball asing incorporating the present invention. This with suitable reenforcing iron, as at I9 and l9a,

though the invention is applicable to a building having any usual or approved type of construction.

The foundation is designated by numeral 20, and is understood to be carried by any usual earth supported footing, not shown. The upper side of the foundation is furnished with fiat surfaces 22 which serve as platforms for longitudinally arranged I-beams 24 which carry ball assemblies on which the super-structure is rested. The number and arrangement. of these I-beams and ball assemblies depends upon the configuration 0f the foundation and the weight to be, carried by it. In the case of a single storygauilding, a single I-beam running around the-upper side of the foundation is usually sufficient, and for the single story part of the building illustrated in Fig. 1, a single I-beam is used on each foundation wall.

At each of the two corners of the foundation which underlie columns I3 and I4, however, a short-length I-beam 25 is employed alongside the end of one of the main I-beamstogive additional weight carrying capacity, the foundation wall being made of sufiicient size to accommodate the extra I-beam, all as clearly illustrated in Figs. 1 and 2. For the two story part of the building of Fig.1, the foundation is shown as made of double width, and a second Ibeam is laid parallel to the first. It will be obvious that as many I- beams may be employed as is necessary for the weight to be carried, and these may be laid as good design dictates. Fig. I shows how, where form type, foundation 28 may be employed, and

may be entirely covered with I-beams 24, arranged as indicated, and welded together at the ends. The junctures of the I-beams, at the corners of the building, or at any angles in the foundation, are welded together, as along the line designated at 26 in Fig. 1. Also, at criticalplaces, steel ties 0r struts. are welded between the 1- beams, as typically indicated at 21 in Figs. 1 and 2. These I-beams 24 are secured to the foundation by means of a suitable number of anchor bolts 30, which are embedded at their lower ends in the concrete foundation, and have screwthreaded upper ends extending up throughholesin the webs of the I-beams, nuts 3! being screwed on the upper ends of the anchor bolts and set down against the I-beam webs The I-beams are preferably further braced by setting their lower flanges 33 down into The upper surface of the foundation walls are thus provided with a continuous steel I-beam tie, made fast to and braced by the concrete foundation. The foundation is also braced diagonally in a horizontal plane, as by diagonal ties such as indicated at 28, anchored at their ends into the concrete.

Secured in similar manner to the undersides of bearing walls I8, which are also braced diagonally,

as by ties 29 anchored at their ends in the walls, and of all supporting columns of the superstructure, are upper I-beams 40, one being arranged over and parallel to each foundation I-beam 24. As clearly shown, the upper Ibeams are of greater width than the lower I-beams 24, and the depending flanges 4! of the upper beams receive between them the upstanding flanges 42 of the lower beams. The upstanding flanges 44 of upper beam 40 preferably are set into the concrete bearing walls l8, and the webs of beams 40 are secured to said walls by means of embedded anchor bolts 45 and nuts 46. The flanges of the upper I-beams preferably engage one another, wherever two are used side by side, and may be fastened together as by welding.

If desired, the interior angles between adjacent walls of the superstructure, and also the foundation, may be additionally braced by use of knee braces such as indicated at 31 in Fig. 1, such braces being anchored to the walls as by anchors 38. In some cases such knee braces may be used without the diagonal'ties, if desired.

Ball and cup assemblies 50 are placed between the webs of the upper and lower I-beams, and

carry the entire load of the superstructure. These respectively, providing concave seats 53 for hard steel balls 54. These balls 54 carry the weight of a high factor of safety against crushing. They may typically be from 1 1 to 3" in diameter, although this suggestion is not to be taken as limitative on the invention. The radius of curvature of 'theconcave seating surfaces 53 is considerably greater than that of the balls, as indicated. Since the curvature of these seats is subject to. rather wide possible variation, depending upon particular conditions to be met, no typical curvature is here specified, beyond to note that the relative curvatures of the balls and their seats are preferably substantially as indicated in Fig. 3 of the drawings. It should be pointed out, however, that the balls should be of uniform diameter, and the curvatures of all sets of bearings should likewise be uniform. However, while all concave bearing surfaces should be uniform with each other, it may be advisable to form each concave bearing surface with a wave, or ,annular depression, concentric with the center of the bearing. The exact nature of such modification of the bearing surface and the benefit gained thereby will be explained hereinafter.

Bearing members 5| and 52 are furnished with rings 51, of an inside diameter substantially equal to the diameter of concave seating surfaces 53. These rings 51 and the bearings themselves are rigidly secured to the webs of the I-beams by means of bolts 58 and nuts 59. The purpose of these rings will appear hereinafter.

The ball and cup assemblies are so placed and distributed over the I-beams asto carry substantially equal loads, considering both the dead and probability-adjusted live loads of the buildof the building is furnished with approximately ,double the number of balls provided for its one story, half.

The building of course stands normally with the balls centered on the concave bearings. Upon horizontal motion of the earth arising from an earthquake, the foundation moves with the earth, while the superstructure, because of its great inertia, and because of the flexible plane" between it and the foundation, tends to hold to position. The movement of the foundation relatively to the superstructure occurs by a rolling action on balls 56. There is of course a reaction set up through the balls which tends to move the superstructure in a direction opposite to that of the earth and foundation movement, and this may cause some movement of the building in a direction opposite to that of the earth shock, but such movement is very small compared to the amplitude of movement of the earth and foundation. As the foundation rolls beneath the superstructure, a large part of the energy of the shock is absorbed in rolling resistance, which of course depends upon the weight of the superstructure. Uniform loading of the balls insures that each ball will absorb its share of energy during this rolling action. Thus, as the foundation is relatively displaced by an earth shock from. its normal position of rest, the balls roll on the foundation and superstructure bearings, the building remaining substantially stationary as regards horizontal movement, or 'moving slightly in a direction contrary to that of the earth shock because of a reactive effect received from the balls. Because of the concavity of the bearings supporting these balls, the building is simultaneously slightly elevated, and on completion of such a displacement movement of the foundation, the weight of the building causes the balls to return on the concave surfaces to centered position, realining the foundation and superstructure. An earthquake causes a vibratory motion of the earth ranging up to A in amplitude for most severe conditions, assuming solid or substantially rigid ground conditions. Accordingly, the foundation is displaced first in one direction and then in another with reference to its normal position of rest, the balls climbing the inclined bearing surfaces to elevate the building with each departure from centered position, and on completion of such movement, descending the bearing surfaces in a path either through center, or to one side of center, to'climb the bearing surfaces in another direction. The foundation will of course follow somewhat of a random path, depending upon the characteristics of the earthquake, but the action will be in the nature of a swing from side to side, the superstructure being alternately raised and lowered as the balls travel up and back down the concave bearings with movement of the foundation first away from and then back toward its normal position of rest. As the vibratory motion of the earth declines in amplitude, the movement of the foundation below and relatively to the superstructure decreases accordingly, and the ball and cup bearing assemblies assure that the building will finally settle back into its original position of rest, with the superstructure again square with the foundation. It will be seen that the overall effect of the ball and cup supporting assemblies is to absorb energy of the shock and to prevent its acceleration from being transmitted to the superstructure of the building.

The flexibility provided by the present invenor unforeseen movements should occur, the overlapped I-beam flanges 4i and 42 would finally engage one another, and that thereafter further play will be afforded in bending of the flanges. This will allow some motion to be transmitted to the superstructure, but even in such event, the building would be reasonably protected by reason of the fact that the shock would be greatly softened before the actual flange engagement could occur. It is contemplated that for an ordinary or small building the upper I-beams may preferably be from three to four inches wider, from flange to flange, than the lower I-beams, so that the flanges will not engage in the manner just described unless a movement should occur of from one and one-half to two inches amplitude. A high factor of safety is thereby afforded since, as noted hereinbefore, it has been estimated that an earthquake of the most severe character so far known would not cause a vibratory earth movement of over substantially amplitude, or of substantially 1" amplitude assuming loose or soft soil. However, as previously stated, if an earth movement of magnitude sufficient to cause engagement of the I-beam flanges should occur, further flexibility and play is afforded in bending of the III-beam flanges, and reasonable protection is therefore had even for extreme conditions far beyond foreseen limits. Preferably, the parts are so related that the balls will strike the rings 5? simultaneously with such engagement of the flanges. These rings are preferably of some soft iron, as wrought iron, and the sharp comer of the washer engaged by the ball is mashed around with any such engagement, so that there is no likelihood of cracking of the balls in meeting the rings. Instead, the balls simply mash a seating surface on the rings and tend to climb over them, and this action, together with bending of the then engaged I-beam flanges, absorbs further energy of the shock, as well as allowing overplayin the' event of earth movements of unexpected magnitude. It has been stated that the upper I-beams may typically be from three to four inches wider, from flange to flange, than the ports for the ball and cup assemblies, in some instances it may be desired to use channel beams in place of I-beams. The present drawings are to be considered illustrative of channel as well as of lI-beams, it being noted that simple removal of the upstanding flanges of the upper I-beam and of the depending flanges of the lower I-beam converts the structure into channel form. The

channel form, in fact, is properly to be regarded as the generic form of the structure.'

It is conceivable, though improbable, that the period of vibration of an earth movement might time" with the natural period of the superstructure, in which event serious movement of the building might occur. Such action is effectively prevented,.however, by forming the concave bearing surfaces as indicated in the enlarged and somewhat exaggerated views of Figs. 5 and 6. In said figures the upper and lower concave bearing surfaces are-again indicated at 53 and the ball is indicated at 54. In this instance, however, a shallow wave or annular groove 51 is formed'in the face of each bearing surface. This groove is preferably very shallow, being perhaps not over several thousandths of an inch deep, though this it not to be taken as limitative on the invention, and'is concentric with'thecenter of the concave bearing face. Any number of such concentric grooves may of course be employed, but one is suflicient for the present illustration. This I groove absolutely prevents the superstructure from timing with the vibratory motion of the earth, as it causes the ball travelling across it to be given a slight tendency for motion around the bearing, as well as to hesitate slightly in crossing the groove, which at once breaks up any tendency for a periodic response of the superstructure to the vibratory earth motion. As stated previously, it is considered only remotely possible that such a periodic response of the superstructure might ever occur, but all practical possibility of such action is removed by provision of the described wave in the bearing surfaces, and this bearing formation may be utilized if deemed desirable. Preferably, after assembly of the I-beam structure, the lower I-beam is filled to the top edge of the flanges with an oil of appropriate type, which provides, first. suitable lubrication for free action of the parts, and second, coverage to prevent corrosion. -At the ends of certain'of the I-beams, or wherever necessary, oil confining plates 59 may be welded between the flanges (see Fig. l)

Supply pipes entering the building are provided with flexible or double swing joint connections which allow ample play in any direction. Ree

ferring to Fig. 4, in which the foundation is again indicated at and the superstructure side wall at l8, three utility pipe lines enter the superstructure indicated at 60, SI and 62. Line 60, which may be considered as a gas line, is shown provided with a flexible section 63, consisting simply of a series of bends or folds 64. Line 6|, which may be a water supply pipe, has a flexible joint consisting of a pair of spaced ball and socket joints 65 and telescopingpipe sections 66 and 61, provided with suitable packing. Line 62 may be a sewer pipe, and may have a flexible joint 69 just like that provided for line 6|. These fleidble connections afl'ord sufllcient play that the pipes will not be broken with relative movement between the earth and superstructure,

In order to provide for overturning moment due to possible wind pressures of unusual or normally unforeseen magnitude, or of earthquake forces, a series of hold-down links Hi is' placed on the basement side of the exterior foundation walls and connected with the superstructure. These links, formed with upper and lower eyes II, are connected top and bottom 'with anchors 13 and I4 embedded in bearing wall l8 and foundation 20 respectively. Suflicient play is aflorded that the links will not tighten within the range of con- The provisions of the present invention absorb a large share of the energy of an earth shock, and reduce to negligible amount the movements transmi ted to the superstructure. The operability f the invention is notobviated in'the event of settling of one end'of the building, the superstructure being capable of the necessary rolling andself-centering action relative to the foundation, even though the foundation is at a considerable angle relative to horizontal.

It'will be understood the drawings 'and description are to be considered as illustrative or rather than restrictive on the broader claims appended hereto,- since various changes in design, structure and arrangement may be made without departing from the spirit and scope of said claims.

I claim:

1. In an earthquake protected building construction, the combination of a foundation structure, a building superstructure over said foundation structure, a set of balls distributed over the upper side of the foundation structure and adapted to receive and carry the load of the superstructure and transmit it to the foundation, and upper and lower concave bearings for the top and undersides of each ball, saidbearings being rigidly mounted on the underside of the superstructure and the top side of the foundation, respectively, and said concave bearing surfaces being circular in formation, of radii of curvature greater than that of the balls, and having secondary concentric circular depressions. 2. man earthquake protected building c onstruction, the combination of a foundationstructure, a building superstructure over said foundation structure, an I-beam mounted on the top surface of the foundation structure, with its web in a horizontal plane, a corresponding I-beam mounted on the underside of the superstructure directly over and parallel to the foundation I-beam, and with its web in a horizontal plane, a plurality of upwardly facing concave bearings rigidly mounted on the upperside of the foundation I-beam web, a like plurality of balls, of radius of curvature less than that of the bearings,

resting on said bearings, and a plurality of down-. wardly facing concave bearings, of radius of curvature greater than that of the balls, rigidly mounted on the lower side of the superstructure directly over and parallel to the foundation I-beam, and with its web in a horizontal plane, the superstructure I-beam' being of flange to flange width greater than that of the foundation I-beam, a plurality 'of upwardly facing concave bearings rigidly mountedon the upper side of the foundation I-beam web, a like plurality of balls,

of radius of curvature less than that of the bearings, resting on said bearings, and a plurality of downwardly facing concave bearings, of radius of curvature greater than that of the balls, rigidly mounted on the lower side of the superstructure I-beam web, and arranged one over and engaged by each of the balls resting on the lower bearings, the bearings and balls being of such vertical thickness relative to the vertical dimensions of the I-beam flanges that the upwardly extending flanges of the foundation I-beam are overlapped by and received between the downwardly extending flanges of the superstructure I-beam.

4. In an earthquake protected building construction-the combination of a foundation wall, a plurality of upwardly facing concavedbearings rigidly mounted on the upper side of said foundation, a like plurality of balls, of radius of curvature less than that of the bearings, resting on said bearings, a superstructure wall over said foundation wall, a plurality of downwardly facing concave bearings, of radius of curvature greater than thatof the balls, rigidly mounted on a downwardly facing surface on the lower portion of said superstructure wall and arranged one over and engaged by each of the balls resting on the concave foundation bearings, and a plurality of tension members connected at their upper and lower ends to the superstructure and foundation walls, respectively.

5. In an earthquake protected building con-' struction, the combination of a foundation wall, a plurality of upwardly facing concave bearings rigidly mounted on the upper surface of said foundation, a like plurality of balls, of radius of curvature less than that of the bearings, resting on said bearings, a superstructure wall over said foundation wall, a plurality of downwardly facing concave bearings, of radius of curvature greater than that of the balls, rigidly mounted on a downwardly facing surface an the lower portion of said superstructure wall and arranged one over and engaged by each of the balls resting on the concave foundation bearings, a plurality of substantially vertically disposed hold-down links extending between and to one side of the superstructure and foundation walls, an anchor member flexibly linked to the lower end of said hold-down link and rigidly connected to the foundation wall, and an anchor member flexibly linked to the upper end of said hold-down link and rigidly connected to the superstructure wall.

faced bearing on the superstructure for the upper side of each ball, and knee braces mounted in interior angles formed by adjacent walls of the superstructure.

I. In an earthquake protected building, the combination of adjoining foundation walls meeting at an angle, bracing means said walls, a superstructure above and separate of said foundation, said superstructure including ad'- joining side walls meeting at an angle, a set of balls distributed over the top surface of the foundation and arranged to support said superstructure side walls on the foundation, a concavely faced bearing on the foundation for the lower side of each ball, a concavely faced bearing on the superstructure for the upper side of each ball, and bracing means engaging said adjoining superstructure side walls, said bracing means .being adapted to brace said walls against relative movement. 8. In an earthquake protected building construction, the combination of a foundation structure, a building superstructure over said foundation structure, a channel beam, arranged with its flanges extending in an upward direction, and with its "web in a horizontal plane, mounted on the top of the foundation, a corresponding channel beam, arranged with its flanges extending in a downward direction, and with its web in a horizontal plane, mounted on the underside of the superstructure directly over the folmdation channel beam, a plurality of upwardly facing concave bearings rigidly mounted on the upper side of the foundation channel web, a like plurality of balls, of radius of curvature less than that of the bearings, resting on said bearings, and a plurality of downwardly facing concave bearings, of radius of curvature greater than that of theballs, rigidly mounted on the lower side of the superstructure channel web, and arranged one over and engaged by each of the balls resting on the lower bearings.

9. In an earthquake protected building construction, the combination of a foundation structure, a building superstructure over said foundation structure, a channel beam, arranged with ,its flanges extending in an.upward directiomand' with its web in a horizontal plane, mounted onthe top of the foundation, a corresponding, channel beam, arranged with its flanges extending in a downward direction, and with its web in a' horizontal plane, mounted on the underside of the superstructure directly over the foundation channel beam, the superstructure channel being of flange to flange width greater than that of the foundation channel, a plurality of upwardly facing concave bearings rigidly mounted on the upper side of the foundation channel web, a like plurality-of balls, of radius of curvature less than that of the bearings, resting on said bearings, and a plurality of downwardly facing concave bearings, of radius of curvature greater than that of the balls, rigidly mounted on the lower side of the superstructure channel web, and arranged one over and engaged by each of the balls resting on the lower bearings, the bearings and balls being of such vertical thickness relative to the vertical dimensions of the channel flanges that the upwardly extending flanges of the foundation channel are overlapped by and received between the downwardly extending flanges of the superstructure channel.

GIUSEPPE CAVAGLIERI.

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