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STEEL CONSTRUCTION
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See also:STEEL CONSTRUCTION . The use of steel construction in the erection of large buildings is the natural consequence of the conditions imposed upon owners of See also:property lying within sections of large cities, and the result of the introduction of new materials and devices. Apart from the aesthetic considerations to which has been due the construction of See also:spires, towers,domes, high See also:roofs, &c., the See also:form and height of buildings have always been largely controlled by a See also:practical See also:consideration of their value for See also:personal use or rental. The cost of buildings of the same class and finish is in See also:direct proportion to their cubic contents, and each cubic See also:foot constructed is commercially unprofitable which does not do its See also:part in paying See also:interest on the See also:capital invested. Until the latter See also:half of the z 9th See also:century, these considerations practically limited the height of buildings on See also:city streets to five or six storeys. The manufacture of the wrought-See also:iron " I " See also:beam in 1855 made cheaper See also:fire-See also:proof construction possible, and, with the introduction of passenger lifts (see See also:ELEVATORS; LIFTS or HOISTS) about ten years later, led to the erection of buildings to be used as hotels, flats, offices, factories, and for other commercial purposes, containing many more storeys than had formerly been found profitable. The practical limit of height was reached when the sectional See also:area of the See also:masonry of the piers of the exterior walls in the See also:lower See also:storey had to be made so See also:great, in See also:order to support safely the See also:weight of the dead load of the walls and floors and the accidental load imposed upon the latter in use, as to affect seriously the value of the lower storeys on See also:account of the loss of See also:light and See also:floor space. This limit was found to be about ten storeys. Various devices were successively made to reduce the See also:size of the exterior piers. In 1881 the walls of a very large courtyard were constructed by See also:building a braced cage of iron and filling the panels with masonry, a See also:system of construction which had been used in the See also:early part of the century for a tall shot-See also:tower erected in the city of New See also:York. Subsequently several buildings were erected in which the entire weight of the floors and roofs was carried by a system of See also:metal columns placed against the inner See also:surface of the exterior walls. The walls thus supported no load but their own weight, and were tied to the inner cage formed by the See also:wall columns, interior columns, girders, and floors by anchors arranged to provide for the shrinkage of masonry in drying out which always occurs to a greater or less extent. By the use of this form of construction buildings were carried to the height of eighteen or nineteen storeys. Iron or steel as a substitute for See also:wood for constructive purposes was See also:long thought to be fire-proof or fire-resisting because it is incombustible, and for this See also:reason it has not only replaced wood in many features of building construction but is also used as a substitute for masonry. In See also:time, however, it was realized that iron by itself is not fire-proof, but requires to be protected by means of fire-resisting coverings; but as soon as satisfactory forms of these were invented their development progressed See also:hand in hand with that of iron and steel forms and combinations. Buildings in steel are either of " See also:skeleton " or " cage " construction: These terms may be defined as follows: In "skeleton" construction the columns and girders are built without proper or adequate inter-connexion and would not be able to carry the required weights without the support afforded by the walls; or, as in more See also:recent construction, the walls are self-supporting and the other portions of the building are carried on by the skeleton steelwork. " Cage " construction consists of a See also:complete and well-connected framework of iron or steel capable of carrying not only the floors but the walls, roof, and every other part of the building, and efficiently constructed with See also:wind bracing to secure its See also:independent safety under all conditions of loading and exposure, all loads being transmitted to the ground through columns at predetermined points. In See also:America under this system the walls can be built independently from any level (see fig. 4), but in See also:England the requirements of the building acts as to the thickness of walls prevents the See also:general use of this form of construction. Skeleton construction is defined by the See also:Chicago building See also:ordinance as follows: " The See also:term ' skeleton construction ' shall apply to all buildings wherein all See also:external and See also:internal loads and strains are transmitted from the See also:top of the building to the See also:foundations by a skeleton or framework of metal. In such metal framework the beams and girders shall be riveted to each other at their respective junction points. If pillars made of rolled iron or steel are used, their different parts shall be riveted to each other and the beams and girders resting upon them shall have riveted or bolted connexions to unite them with the See also:pillar, if See also:cast-iron pillars are used, each successive pillar shall be bolted to the one below it by at least four bolts not less than three-fourths of an See also:inch in See also:diameter, and fhe'beams and girders shall be bolted to the pillars. At each See also:line of floor- or roof-beams, lateral connexion between the ends of the beams .and girders shall be made by passing wrought-iron or steel straps across or through the cast-iron See also:column, in such a manner as to rigidly connect the beams and girders with each other on the direction of their length. These straps shall be made of wrought-iron or steel, and shall be riveted or bolted to the flanges or to the webs of the beams or girders. If buildings are made fire-proof entirely, and have skeleton construction so designed that their enclosing walls do not carry the weight of the floors or roof; then their walls shall be not less than twelve inches in'thicknest; and provided, also, that such walls shall be thoroughly anchored to the iron skeleton, and provided, also, that, whether the weight of such walls rests upon beams or pillars, such beams or pillars must be made strong enough in each storey to carry the weight of wall resting upon them without reliance upon the walls below them. All partitions must be of incombustible material." With the introduction of cheap structural steel, steel cage construction came rapidly into use. The dimensions of the exterior piers ceased to See also:control the height of the Steel See also:case building, which was limited alone by the possibility Construe - of securing adequate foundationsr and by a considera- tion. tion of the amount of floor space which could be devoted without too great loss to a system of passenger lifts of sufficient capacity to afford speedy See also:access to all parts of the building. The advantages that led to the very rapid introduction of this system were not only the See also:power of greatly redncing the size of the piers, but the enormous facility afforded for See also:quick construction, the small amount of materials relatively used and the proportionately small load upon the foundations, and the fact that as the walls are supported at each storey directly from the cage, the masonry can be begun at any storey independently of the masonry below it. It is a disadvantage of the system that defects of proportion, material, or workmanship, which would be of less moment in an old-fashioned construction, may become an See also:element of -danger in building with the steel cage, while the possibility of securing a permanent See also:protection of all parts of the cage from corrosion is a most serious consideration. The safety of the structure depends upon the preservation of the See also:absolute integrity of the cage. It must not only be strong enough to sustain all possible See also:vertical loads, but it must be sufficiently rigid to resist without 'deformation or weakening all lateral disturbing forces, the See also:principal of which are the pressure of wind, the possible sway of moving crowds or moving machinery, and the vibration of the See also:earth from the passage of loaded vans and trolleys, and slight earthquakes which at times visit almost all localities. In buildings wide in proportion to their height it is the See also:ordinary practice to make the floors sufficiently rigid to See also:transfer the lateral strains to the walls, and to See also:brace the wall framings to resist them. In buildings of small width in proportion to their height this method ' of securing rigidity is generally found to be inadequate, and the See also:frame is also braced at right angles to the See also:outer walls to take up the strains directly. In each case all strains are carefully computed. The bracing is accomplished by the introduction at the angles of the columns and girders or beams of gusset plates or See also:knee braces, or by See also:diagonal straps or rods properly attached by See also:rivet or See also:pin connexions. All portions of the frame are See also:united byhot rivets of mild steel or wrought iron, care being taken that the sum of the sectional areas of rivets affords in each case a sufficient amount of metal for the safe transfer of the stresses. The greatest care should be taken to see that all rivet holes are accurately punched, and if necessary that they are rhymed so that each rivet will have its full value. -
For the proper and successful erection of the frame much depends upon an accurate alinement of the column bases. These should be properly tested as to position and level. The bases are either grouted with See also:cement, or bolted to the foundations, but where cast column bases See also:rest on masonry piers or footings any considerable grouting is not advisable. The only grouting that should be permitted in tall buildings would be inlevelling. up the tops of the See also:concrete footings- to receive the masonry courses, or in a very thin layer between the column See also:pedestal and the masonry See also:bed. The cap stones should always be brought to the most accurate bed possible, with grouting used as a thin cement and not as a backer. Accurate redressing of the cap stones after setting is much to be preferred.
All riveting and punching of the steel members is done at the See also:shop, where also they receive the usual coat of oil or paint. This leaves the assembling and See also: In See also:German specifications it is corrosion, required that the steelwork should first receive a - coat of boiled See also:linseed oil, in order that the red lead coating should be more -coherent with the steel.
Steelwork that has to come in contact with See also:brickwork or concrete should not be painted, but should receive a See also:wash of cement as the brickwork or concrete-See also:work proceeds. The steelwork which is exposed to the See also:weather should be painted about every three years, but when it is under See also:cover an See also:interval of five years may elapse.
To secure painting of permanent value a clean scaleless and rustless surface is first necessary. Steel plates and shapes, when delivered from the rolls which form them to the cooling beds, - are largely covered with scales, which, adhering only partially to the surface, offer the intervening cracks or See also:joints as vulnerable points for See also:rust. After being rolled, structural steel is stored or handled out of doors for a varying See also:period both at the See also: Where surfaces in riveted work come in See also:con-tact they shall be painted before assembling. After erection all work shall be painted with at least one additional coat. All iron or steel used under See also:water shall be enclosed with concrete." The Chicago ordinance makes no mention of paint or coating to prevent rust in- metal framework. The See also:London Building Acts do not set out any See also:special' requirements, but suggestions. have been made at the Royal -Institution of See also:British Architects for the -regulation of skeleton buildings and they are See also:drawn up upon a more scientific basis than the bulk of the existing acts. In transferring the loads from the column bases to the bottom of the footings the greatest care must be taken in all systems of construction that the stresses throughout at no Columns. point exceed the safe limits of stress for the various materials used. Steel is generally used for columns in preference to cast iron, because it affords greater facility for securing satisfactory connexions, because its defects of quality or workmanship are more surely detected by careful test and inspection, and because, on account of its See also:superior See also:elasticity and ductility, its fibre is less liable to fracture from slight deformations. It is used in preference to wrought iron on account of its lesser cost. Columns are generally built of riveted work of zedbars, channels, angles, plates, or lattice, of such form as will make the simplest and most easily constructed framing in the particular position in which the column is placed. The columns are sometimes run through two or more storeys and arranged to break joints at the different floors. In buildings to be used as offices, hotels, apartments, &c., it is usual in establishing the loads for the purpose of computation to assume that the columns carrying the roof and the upper storey will be called upon to sustain the full dead load due to material and the maximum computed variable load, but it is customary to reduce the variable loads at the See also:rate of about 5% storey by storey towards the See also:base, until a minimum of about 20% of the entire variable load is reached; for it is evidently impossible that the building,can be loaded by a densely-packed moving See also:crowd in all of its storeys simultaneously. In the case of factories and buildings'used for storage purposes the maximum variable load which can be imposed .for . any serious length of time on each floor must be used without reduction in computing the loads of the lower column, and proper allowances must be made for vibrating loads. In the case of very tall exposed buildings of small See also:depth, the vertical load. on the columns due to wind pressure in the opposite See also:side of. the building must be computed and allowed for, and in case the lower columns are without lateral support their bending moment must be sufficient to resist the lateral pressure due to wind and eccentricity of loading. In computing the column sections a proper See also:allowance must be made for any eccentricity of loading. It is usual to limit the height of sections of columns without lateral support to 30 diameters, and to limit the maximum fibre stress to 12,000 lb per sq. in. The sectional areas are computed'by the use of the ordinary formulae for columns and struts. The See also:standard sections in use are numerous and varied, and from time to time a steel user has occasion to See also:design a new steel shape because no existing See also:section is suitable. The experiments given by See also:Professor See also:Burr indicate that a closed column is stronger than an open one, but practice does not always sup-See also:port theory, and many other questions besides See also:mere form arise in connexion with the choice of a section; special considerations in the use of columns in buildings sometimes See also:call for a form very different from the circular section, and such include the transfer of loads to the centre of the section, the maximum efficiency under loading, and the requirements for See also:pipe space around or included in the column form. Lattice bars, fillers, brackets, &c., add just so much more weight without increasing the section, and must be allowed for; the method of riveting the sections together must also be taken into account. For girders of small spans " I " beams or channels are generally used, but for greater spans girders are built of riveted work Girders in the form of boxes with top and bottom plates, side plates, and angles with proper stiffening bars on the side plates, or " I's," or lattice, or other forms of See also:truss work. In girders and beams the maximum fibre stress is usually limited to i6,000 lb. In very See also:short girders the shear must be computed, and in long girders the deflexion, particularly the flexure from the variable load, since a flexure of more than See also:spa of the length is liable to crack the plastering of the. ceilings carried by the girders. The same See also:necessity for computing shear.and flexure applies to the floor beams. The floors between the girders are constructed of " I" beams, spaced generally about 5 ft. between centres; their ends are usually framed to See also:fit the form of the girders, and rest either upon their, lower flanges, or upon seats formed of angles riveted to their webs, being secured to them by a pair of angles at each end of the beam riveted to its See also:web and to the web of the girder. Some-times the beams rest upon the girders, and are riveted through the flanges to it; in this case the abutting ends of beams are spliced by See also:scarf plates placed on each side of the webs and secured by rivets. A similar construction is followed for See also:flat, roofs, the grades being generally formed in the girder and beam construction, and a flat See also:ceiling secured by See also:hanging from them, with steel straps, a light tier of ceiling beams. The floor beams, are tied laterally by rods in continuous lines placed_at or abovetheir neutral See also:axis. It is usual in both girders and beams to provide not only for the safe support of the greatest possible distributed load, but for the greatest weight, such as that of a safe or other heavy piece of See also:furniture which may be moved over the floor at its weakest points, the centres of the girders and beams. It must always be See also:borne in mind that the formulae for the ultimate strength of the ".I " beams only hold See also:good when the upper chord or flange is supported laterally. Considerable improvement has been made in the design of rolled steel shapes; for example the See also:rolling of a i6-in. See also:joist was formerly deemed a remarkable achievement, though now there are several See also:works producing 24-in. joists with flanges 7 and 71 in. wide. The Broad Flange Differdange Beams are claimed by the manufacturers to be stronger and to minimize weight for use as girders; they are made in twenty-one different sizes with flanges from 81 to 12 in. wide. The introduction of steel construction has simplified many details of architectural treatment, such as projections for cornices, See also:bay windows and galleries. These may be supported by See also:bracket-angles attached to the columns with a system of anchors to tie them back; the material must be carried in such a manner as to make it independent of the general structure, and must be constructed as light as possible. If the supporting member is a floor beam or girder the girder should be rigidly connected to the floor system to prevent any twisting due to the weight of the See also:projection. The arrangement of the building and floor framings is in a great measure governed by the architectural effect sought and by the arrangement and proper planning of the Floors. interior according tQ the intended uses; the positions of columns, girders and floor beams are usually the result of particular requirements, and unless complicated and expensive framing is to be expected the distance between columns must be kept within the limits of See also:simple girder construction. The position of the columns having been determined, the girders must next be located; these serve to support the floor beams which transfer the loads direct to the columns, and also to brace the columns during erection. The spacing, or distance from centre to centre of the floor beams, will depend upon the type of fire-proof flooring employed; it also depends to a considerable extent upon the amount and See also:character of the floor load and the length of span. If the loads to be carried are largely stationary, and if the span is small, the floor joists can be readily proportioned by means of tables given in the handbooks issued by many steel companies. The distance between joists should be limited to 5 or ¢ ft.; See also:horizontal bracing by means of diagonal rods is sometimes used, but should be avoided. The following are the usual assumptions made in good practice for super-imposed loads: Floors of dwellings and offices . . 70 lb per sq. ft. „ churches, theatres and See also:ball-rooms 125 , „ „ warehouses 200 to 25o „ for heavy machinery . . . 250 to 400 ;, „ The relation between the velocity of wind and the pressure exerted upon surfaces must be considered in steel construction, and designers differ in regard to the forces to be wind. resisted and the material to be used. Every building bracing. offers its own See also:peculiar See also:condition; the height, width, shape and situation of the structure, and • character of the enclosing walls, will determine the amount of wind pressure to be provided against, and the internal See also:appearance and the planning of the various floors will largely See also:influence the manner in which the bracing is to be treated. There are many and varied forms of bracing, each designer adopting methods peculiar to his own ideas. One form consists of adjustable diagonals, rods or bars, properly fastened to the columns in the building; these diagonals may run through one floor and be attached to the columns at the floor above. Another form is known as portal bracing; this is usually braced between adjacent columns in halls or passage-ways and extends from the foundations up from floor to floor to such a height that the stability of the building itself is sufficient to resist the assumed wind pressure. In general, if the building is square or nearly so wind-bracing should be placed See also:close to the corners. In case neither of the above methods can be applied, brackets should be used at each floor level or a continuous deep beam or girder carried all around the building. Some architects depend solely upon partitions, and a building with a well-constructed iron frame should be safe if provided with See also:brick partitions or if the exterior of the iron framework is covered with well-built masonry of sufficient thickness. Truss rods, portals, or lattice or See also:plate girders constitute the more definite types of wind-bracing ordinarily employed; the bracing must reach to some solid connexion at the ground. The greatest wind pressure to which a building is subjected is that from a horizontal wind. The maximum pressure is not See also:uniform from the ground level to the roof but is greatest at the centre; it is diminished near the ground level by the frictional resistance of the ground, and at the See also:eaves by the eddies formed by the air escaping over the roof. The See also:change in direction of the air when striking a flat surface such as the side of a building will form a See also:cushion to diminish the effects of impulses and shocks from See also:local gusts. The building See also:laws of the city of New York require the following provisions as regards wind forces: " All structures exposed to wind shall be designed to resist a horizontal wind pressure of See also:thirty pounds for every square foot . of surface thus exposed, from the ground to the top of the same, including roof, in any direction. In no case shall the overturning moment due to wind pressure exceed seventy-five per centum of the moment of stability of the structure. In all structures exposed to wind, if the resisting moments of the ordinary materials of construction, such as masonry, partitions, floors and connexions, are not sufficient to resist the moment of distortion due to wind pressure, taken in any direction on any part of the structure, additional bracing shall be introduced sufficient to make up the difference in the moments. In calculations for wind pressures, the working stresses set forth in the See also:code may be increased by fifty per centum. In buildings under one See also:hundred feet in height, provided the height does not exceed four times the See also:average width of the base, the wind pressure may be disregarded." The steel used throughout the entire structure should be subjected to the most thorough chemical and See also:mechanical tests and inspection, first at the mill and subsequently at Materials the fabricating shops and the building, to ensure that Used it shall not contain more than o•o8% of See also:phosphorus or o•o6% of See also:sulphur, that it shall have an ultimate strength of between 6o,000 and 70,000 lb per sq. in., with an elastic limit of not less than 35,000 lb per sq. in., and an See also:elongation before fracture of not less than 25% in 8 in. of length, and that a piece of the material may be See also:bent See also:cold 18o° over a mandril equal to the thickness of the piece tested without fracture of the See also:fibres on the outside of the See also:bend. At least two pieces are taken from each melt or See also:blow at the mill, and are stamped or marked, and all the various sections rolled from the melt or blow are required to See also:bear a similar See also:stamp or See also:mark for See also:identification. All finished material is carefully examined to see that it possesses a smooth surface, and that it is See also:free from cracks, seams and other defects, and that it is true to section throughout. Rivets are either of wrought iron or of extra soft steel, with an ultimate tensile strength of 55,000 lb per sq. in. The material must be sufficiently tough to bend cold 180 flat on itself without sign of fracture. The greatest care is taken that no steel is See also:left in a brittle condition by See also:heating and cooling without proper See also:annealing. All abutting joints in riveted work are faced to exact lengths and absolutely at right angles to the axis of the piece, and are spliced by scarf plates of proper dimensions adequately secured by rivets. The work should be so accurate that no packing pieces are necessary. If the conditions are such that a packing or filling piece must be used, the end of one piece is cut to a new and true surface, and the tilling piece is planed to fill the space accurately. Where cast iron is used it must be of tough See also:grey iron free from defects. In testing it pieces 14 in. long and r in. square are cast from each See also:heat and supported on See also:blunt See also:knife edges spaced 12 in. apart; under a load in the centre of the piece of 2500 lb the deflexion must not exceed in. The filling between the girders and floor beams consists of segmental See also:arches of brick, segmental or flat arches of porous (sawdust) terra-See also:cotta, or hard-burned hollow terra- Floor-tJttag cotta voussoirs, or various patented forms of con- and See also:Crete floors containing ties or supports of steel or Paruuoas. iron. In all cases it is customary to fill on top of the arches with a strong See also:Portland cement concrete to a uniform level, generally the top of the deepest beam; the floor filling is constructed and carried to this level immediately upon the completion of each tier of beams, for the purpose not only of stiffening the frame laterally, and of adding to its stability by the See also:imposition of a static load, but also to afford constantly safe and strong working platforms at See also:regular and convenient intervals for use throughout the entire period of the construction. In cases in which the lateral rigidity of the floors is depended upon to transfer the horizontal strains to the exterior walls which are framed to resist them, no form of floor construction should be used which is not laterally strong and rigid. With very rapid building, no method of construction of floors furrings, or partitions should be adopted which will not dry out with great See also:speed. In flat forms of masonry floor construction the level of its bottom is placed somewhat below the bottom of the " I " beams and girders, so that when it is plastered a continuous surface of at least an inch of See also:mortar will form a fire-proof protection for the lower flanges of the beams and girders. Where the width of the flange is considerable it is first covered with metal See also:lath secured to the under side of the floor masonry. Girders projecting below the floor are usually encased in from i to 2 in. of fire-proof material, 2 or 4 in. of which is also put on all columns. Such fire-proof coverings, and also interior partitions, are composed of hollow, hard-burned terra-cotta blocks, of porous (sawdust) terra cotta, or various plastic compositions applied to metallic lath, many of which are patented both as to material and method of application. The most simple test for the value of a system of fire-proof coverings, and of partitions and furrings, is to erect a large See also:sample of the work and to subject it alternately to the continued See also:action of an intensely hot See also:flame which is allowed to impinge upon it, and to a stream of cold water directed upon it from the ordinary service nozzle of a See also:steam fire See also:engine. It is important in all fire-proofing of columns and girders, and in all floor construction, furring and partitions, that there shall be no continuous voids, either vertical or horizontal, which may possibly serve as flues for the spread of heat or flame in case of fire. All furrings and partitions must be started on the solid masonry of the floors to prevent the possible passage of fire from the See also:room in which it may occur. The failure to make this See also:provision has been the cause of very serious losses in buildings which were supposed to be fire-proof. Steel construction possesses great advantages in time required for erection. When once the site is cleared and the foundations prepared and set, work can be pushed on the Time and walls at different storeys at one and the same time, cost of and often See also:main cornices and filling-in work are U''ectioa. fixed before special details and ornamentation. In the Commercial See also:Cable Building, New York, seven complete tiers aggregating 7000 tons were erected in nine See also:weeks. In the Unity Building, Chicago, of seventeen storeys, the metal frame-work from See also:basement columns to finished roof was accomplished in nine weeks. In the See also:Fisher Building, Chicago, the entire steel skeleton above the first floor, nineteen storeys and See also:attic, was erected in twenty-six days.
Owing to the See also:low See also:price of steel it is possible to make a steel column of See also:equivalent strength cheaper than one in cast iron. The question of cost is purely a commercial one, but the cost of the raw material will practically never determine the relative cost between various forms, as the expense of manufacture and the detail and duplication of members will all influence the ultimate cost to a much greater extent than the simple cost of the See also:plain materials. The steelwork for a building of any considerable size is almost invariably rolled to order.
Steel construction and the rapid development of See also:engineering The famous See also:literary pair were See also:born in the same See also:year. See also:Steele, the See also:senior by less than two months, was baptized on the 12th of See also: Addison's father also took an interest in the warm-hearted See also:young Irishman; but their combined influence did not steady him sufficiently to keep his impulses within the lines of a regular career; without waiting for a degree he volunteered into the See also:army, and served for some time as a See also:cadet " under the command of the unfortunate See also:duke of Ormond " (i.e. the first duke's See also:grandson, who was attainted in 1715). This escapade was made without his uncle's consent, and cost him, according to his own account, " the See also:succession to a very good See also:estate in the See also:county of See also:Wexford in See also:Ireland." Still, he did not lack See also:advancement in the profession he had chosen. A poem on the funeral of See also:Queen See also:Mary (1695), dedicated to See also:Lord Cutts, See also:colonel of the See also:Coldstream See also:Guards, brought him under the See also:notice of that nobleman, who took the See also:gentleman trooper into his See also:household as a secretary, made him an officer in his own See also:regiment, and ultimately procured for him a captaincy in Lord See also:Lucas's regiment of foot. His name was noted for promotion by See also: In his next comedy, The Lying See also:Lover; or, the Ladies' Friendship, based on See also:Corneille's Menteur, produced two years afterwards, in See also:December 1703, Steele's moral purpose was directly avowed, and the See also:play, according to his own statement, was " damned for its piety." The See also:Tender See also:Husband, an See also:imitation of See also:Moliere's Sicilien, produced eighteen months later (in April 1705), though not less pure in See also:tone, was more successful; in this play he gave unmistakable See also:evidence of his happy See also:genius for conceiving and embodying humorous types of character, putting on the stage the parents or grandparents of See also:Squire Western, Tony Lumpkin and See also:Lydia Languish. It was seventeen years before Steele practice has affected not only the erection of tall buildings, but has also produced improvement in the erection shops consist of wider buildings of greater height with plenty of roof-light, efficient See also:ventilation, and artificial heating, and as the heavy loads can be carried by the reinf arcing material, heavy walls become unnecessary. Gradually, therefore, the See also:modern steel-framed factory has been evolved, capable of supporting all the loads, the outer walls being required only for protection against weather. Light steel roof trusses have replaced the See also:timber trusses, and with the columns form a rigid framework to resist the structural and wind loads as well as those from the See also:cranes and shafting. In See also:Germany skeleton steel-framed factory buildings may be erected with half brick (12 cm.), with a restriction that when such buildings are abutting or are in the immediate See also:neighbour-See also:hood, i.e. within 20 ft. of a neighbouring building, the outside walls on the sides affected shall be full brick (25 cm.). The permissible height to which a building may be erected on the See also:continent of See also:Europe depends largely on the breadth of the road on which such buildings are situated. As a See also:rule it is not permissible to erect a building wider than the road, measured from building line to building line. In See also:American practice the use of steel in buildings of ten or more storeys, or in manufacturing plant where the floor loads are heavy and frequently " live " in the sense of causing vibration, has led to more careful specifications as to the quality of materials and character of workmanship, and it is the See also:custom of the leading architects to have the structural frame inspected and tested during manufacture at the foundries, rolling-See also:mills and shops by a See also:firm of See also:engineers making a speciality of such inspections. The illustrations (see Plates I. and II.) will give a good See also:idea of the general construction as now carried out in England and America. Additional information and CommentsThere are no comments yet for this article.
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