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 J -MT -LIBRARY 
 
 OF THE 
 
 UNIVERSITY OF CALIFORNIA 
 
 GIRT OR 
 
 Received '._.. ... 
 Accessions No. 3^ ^33 Shelf No. 
 
RAILWAY MASONRY 
 
 AND 
 
 BRIDGE FOUNDATIONS, 
 
 BY 
 
 JAMES HASLEY, 
 
 MASTER MASON LITTLE ROCK & FORT SMITH RAILWAY. 
 
 CHICAGO: 
 
 THE RAILWAY AGE PUBLISHING CO. 
 1883. 
 
DEDICATORY. 
 
 To THEODORE HARTMAN, of the Little Rock & Fort 
 
 Smith railway, to whom I owe my sincere thanks for many 
 
 acts of unostentatious kindness, doubly appreciated when 
 
 conferred by an employer upon his employe, this little 
 
 work is respectfully dedicated, with the regret that it is 
 not more worthy, ^,7/^3 3 
 By the author, 
 
 JAMES HASLET. 
 
 ON THE ROAD: 
 
 December 1, 1882. 
 
OOIVTE7VTS. 
 
 CHAPTER I. ' PAGE. 
 Introduction 5. 
 
 CHAPTER II. 
 Various kind of stone. Styles of masonry 8 
 
 CHAPTER III. 
 Various styles of dressing. Pointing joints 15 
 
 CHAPTER IV. 
 The foundations 19 
 
 CHAPTER V. 
 Manner of construction. Abutments 29 
 
 CHAPTER VI. 
 Box and arch culverts 34 
 
 CHAPTER VII. 
 Hydraulic foundations 40 
 
 CHAPTER VIII. 
 Concrete work 57 
 
 CHAPTER IX. 
 Protection against scour 62 
 
RAILWAY MASONRY 
 
 CHAPTER I. 
 
 INTRODUCTION. 
 
 I propose in this little work to treat upon the subject of rail- 
 way masonrj , devoting attention more particularly to the foun- 
 dations and masonry of heavy bridge work, but by no meaus 
 ignoring those works of lesser magnitude known as culverts. 
 With no impracticable theories to advance, no costly experi- 
 ments to advocate, I shall on the contrary merely offer such re- 
 marks and suggestions as are based upon the actual experience 
 of several years as working mason and foreman in all classes of 
 general railway work in stone, brick and concrete, with the hope 
 that such experience may prove valuable to those who may be 
 interested in the matter. 
 
 No one can with propriety question the great superiority of well 
 constructed masonry, over structures of wood, not only in point 
 of solidity and permanence, but also of economy in the long run. 
 Well constructed masonry should never require repairs, never 
 need renewing. Its first cost should be its only cost. Though 
 superstructures should decay and drift away, though embank- 
 ments should crumble and wash out, masonry should stand as 
 one great mass of solid rock, firm and enduring. 
 
O RAILWAY MASONRY 
 
 Several items require especial attention in the construction of 
 masonry for water ways, to render it permanent and of value. 
 Thevare: 
 
 1. The selection of stone of proper quality, which will not 
 soften or decompose, crack or scale off from exposure either to 
 air or water. 
 
 2. Proper dressing of the stone to true and level beds and 
 reasonable joints. 
 
 3. The use of mortars composed of proper materials in proper 
 proportions and thoroughly incorporated with each other. 
 
 4. Firm and solid foundations, with the footings at such depth 
 as will cause no danger from the scouring action of the current. 
 
 5. Conscientious and thorough workmanship. 
 
 Some roadmaster, recently from the scene of a disastrous and 
 expensive washed-out culvert may suggest another item, that of 
 " Sufficient width of opening." But that in my opinion is en- 
 tirely a matter of judgment. The stream at its ordinary stage 
 may appear so trivial and insignificant as to require but a narrow 
 opening way. After excessive rainfall the same stream may 
 rise rapidly and swell to considerable proportions, carrying a 
 large volume of water which not finding ample outlet sweeps 
 away the superstructure and washes out the roadbed. But if 
 the masonry is constructed with due regard to the above enum- 
 erated items the abutments and piers will remain uninjured 
 and intact. Therefore the disaster could not be attributed to the 
 masonry, as the same would have occurred in the case of a tim- 
 bered culvert with only equal width of water way, with the 
 great probability that unless well piled and very strongly built 
 the entire wood work, with considerable of the embankment, 
 would have washed out and away. 
 
 The width of opening, therefore, is foreign to the subject of 
 
RAILWAY MASONRY. 7 
 
 masonry, although intimately related to it, and deserving consid- 
 erable thought, observation and judgment. Ample provision 
 should be made for the passage of unusually large quantities of 
 water, although it might not be required one time in many 
 years. 
 
RAILWAY MASONRY. 
 
 CHAPTER II. 
 
 VARIOUS KINDS OF STONE STYLES OF MASONRY. 
 
 The first point to be observed in the building of masonry is 
 the kind and quality of the stone. For bridge work granite is, 
 beyond all doubt, the most beautiful and durable. Although of 
 several different colors and of varied granulation still it is almost 
 uniformly of the same weight and crushing resistance. This stone 
 being found in large masses and unstratified, in addition to its 
 great hardness, renders it a very costly stone to quarry and dress. 
 I have never seen but one lot of inferior granite, and that was 
 due to the excessive presence of mica. 
 
 Most of the limestones are very suitable for pier and abutment 
 work. They occur in layers of various thickness, the stone be- 
 ing very close grained and dressing freely. The blue limestone 
 is very dense and weighs about the same as granite, which is 165 
 pounds to the cubic foot. The white and magnesian limestones 
 are not so heavy, and when quarried are quite soft, more espe- 
 cially the magnesian, which can be cut with an ordinary pen knife, 
 the same as chalk. Exposure to the air hardens either variety 
 and they answer quite satisfactorily for railway work. Some 
 limestones, however, have a tendency to slake and decompose on 
 exposure to the air and water. 
 
 Another very fine stone, which is rarely found imperfect and 
 which preserves its integrity throughout, is the basalt or blue flag- 
 stone. It, too, Is a stratified stone, with nearly level beds. It 
 splits and works very freely in the direction with its grain, but ia 
 exceedingly difficult to work satisfactorily transversely. It is ex- 
 
RAILWAY MASONRY. 9 
 
 tremely heavy, weighing about 170 pounds to the cubic foot, and 
 can bear much greater transverse strain than any other variety 
 of stone. The smoothness of its beds and its great strength 
 have rendered it the favorite for flagging, curbing and covering 
 of vaults and box culverts. Upon the line of the Little Rock & 
 Fort Smith railway there is a very fine quarry of this stone in 
 layers varying from three inches up to nine and ten. At one 
 point a nine-inch layer is uncovered disclosing one perfect stone 
 19 teet in length by 7 feet in width, and many others nearly as 
 large. 
 
 At Mill Creek the company have a quarry of the same stone 
 existing in heavier layers. I have used many blocks of stone 
 from this quarry measuring seven and eight feet in length by 
 two to three wide, and from two to two and a half in height, 
 weighing from four to five tons each. I have split this stone 
 lengthwise from fifteen to twenty feet with one ounce of powder. 
 Fortunately I was located on the hillside above the track, and 
 simply snubbed it down the bill with a rope and levers onto the 
 cars. At the work I drag it in on skids and rollers operated by a 
 crab and rope. However, this is off the subject, only serving to 
 fehow at what little cost work can be done with such stone. 
 
 Sandstone is the only class which requires the exercise of 
 much judgment and caution. It is so varied in character, 
 its ingreuients are so diversified and so dissimilarly incorporated, 
 its texture and weight are so unlike, that considerable inquiry is 
 needed to make sure that it is suitable for railway work. Sand- 
 stone is nothing more nor less than sand agglutinated or con- 
 creted with soil and mineral substances, such as mica, iron, clay, 
 loam, ochre, marl, etc., etc., in hap-hazard proportions, and its 
 worth as building material is as variable as are the ingredients 
 which compose it. 
 
10 RAILWAY MASONRY. 
 
 All sandstone hardens to a greater or less extent upon exposure 
 to the atmosphere, although nearly all that is of large coarse 
 grain and excessive earthly matter will even then be so weak and 
 friable as to be unfit for use on account of the scaling off and 
 crumbling away of the particles. 
 
 Sandstone is of various colors and shades (which become very 
 dingy in course of time) and exists in the form of boulders and 
 also in slratas or ledges. It can sustain but little strain across 
 its grain, i. e. transversely. In weight it varies from 100 to 130 
 pounds to the cubic foot and is by far the easiest and cheapest 
 stone to quarry and dress. 
 
 The next point to be observed is the proper dressing of the 
 stone to true and level beds and also close }oints, if first quality 
 
 ORDINARY .HUBBLE, WITH DRESSED QUOIN. 
 
 work is desired. I have seen some very stable work put up of 
 only the ordinary " rubble," (see illustration) without any 
 dressing except of adraft on the quoins by which to plumb the 
 
RAILWAY MASONRY. 
 
 11 
 
 corners and carry them up neatly. A few strokes of the hammer 
 were alsp necessary occasionally to spall off any projections or 
 surplus stone. But this style of work is not generally advisable, 
 as very few mechanics could be relied upon to take the proper 
 amount of care in spalling and leveling up the beds and filling 
 the ragged joints of such work. As a consequence one small 
 stone may jar loose and fall out, resulting probably in the 
 downfall of a considerable part of the abutment. However, as 
 most bridge masonry is far more expensive and massive than is 
 generally required, I shall again allude to this class of work under 
 the head of " workmanship." 
 
 Another style of cheap work is that known as " broken ashlar" 
 and "bond rubble" or "rubble range work". The broken 
 
 CT^^ 
 
 BROKEN ASHLAR, OR RUBBLE RANGE WORK. 
 
 ashiar is a dressed stone, but instead of every stone in the 
 course being of the same height, ,it is admissible to use some of 
 the proper height of the course and also some not of the proper 
 
12 
 
 RAILWAY MASONRY. 
 
 height, but which must be brought up to the level of the others 
 by building more upon them. Bond rubble, or rubble range work 
 is built upon the same style, only of undressed stone, for which 
 the stratified stones are eminently suitable. Any protuberances 
 upon the beds are axed off and a very ragged joint may be roughly 
 hammer-dressed. All of the stratified stones can be laid very 
 economically and to good effect, either in broken or unbroken 
 courses. 
 
 Some of these naturally bedded stones are so smooth and uni- 
 form as to need no dressing or spalling up. In such case no 
 further search for stone is necessary, and a great expense for cut- 
 ting is saved and strong massive work is ensured. 
 
 CUT ASHLAR, WITH PLAIN FACE AND EDGES. 
 
 But the majority of these ready bedded stones have more or 
 less inequalities, and iu order to keep them level in the course it 
 becomes necessary to raise them up. perhaps at one corner, per 
 
RAILWAY MASONRY. 
 
 13 
 
 haps at another or both, as the case may be, by placing a chip or 
 chips of stone, called spalls, under the bed, and slushing the va- 
 cant spaces well and full with mortar. And it is just here that 
 the disadvantage of this style of work becomes apparent. Unless 
 the mason distributes these spalls under the stone so that it sets 
 firmly and does not rock, unless these spalls are placed so that 
 all parts of the stone sustained by them distribute their weight 
 and pressure equally, such stone will in all probability become 
 ruptured and split, and a few such instances in the same work 
 may occasion considerable disaster. But with proper care such 
 class of work under ordinary conditions proves to be all that is 
 needed, and if neatly jointed with good cement mortar will also 
 appear to good advantage. 
 
 PITCHED FACED ASHLAR. 
 
 The more expensive and generally preferable class of masonry 
 is that known as ashlar. This is cut stone, accurately dressed 
 and laid either in broken or unbroken ranges. Unless the dress- 
 
K RAILWAY MASUXUY. 
 
 ing on such work be very precise its superiority ceases to exist. 
 Especially must the bed be cut level and true, so that each part of 
 its surface bears an equal proportion of the entire burden ; no 
 hollows, no scantiness, no bumps can be allowed. The aid of 
 spalls should never be needed to get any cut stone in proper posi- 
 tion. If it were otherwise what use would there be of expend- 
 ing time and money in cutting such stone? Generally such 
 cutting is done well and accurately, and in works of considerable 
 magnitude ashlar wort is most frequently made use of. 
 
RAILWAY MASONRY. 15 
 
 CHAPTER III. 
 
 VARIOUS STYLES OF DRESSING. POINTING JOINTS. 
 
 In order to please the eye various styles of dressing the faces 
 of stone work have been adopted, and that to be chosen de- 
 pends upon the taste of the builder. Such dressing is merely 
 for external effect and bears no relation whatever to the strength 
 and durability of the work, for as before remarked, the only 
 points essential are the dressing of the stone to true and level 
 beds and reasonable side joints. Unlike most other work the 
 masonry of railway bridges is very little seen by the general 
 public, to whose eye the builders of other work almost invariably 
 cater. Therefore money expended in costly styles of stone 
 cutting on rail * ay bridge work serves no practical purpose and 
 gratifies the eye of no one but the builder and the track walker. 
 For these reasons the style of dressing generally chosen for the 
 faces of abutments and piers is the ordinary face of the stone as 
 it leaves the quarry, be that face plain and straight, indented or 
 protruding. This is called quarry or rock faced. If some of the 
 stones have a rather dull, smooth face, and are to be set in a 
 course with others the faces of which are bold and projecting, it 
 is in good taste to pitch the edges of the smooth faced ones off, so 
 as to cause the centre of the face to project to some extent beyond 
 the edges, by which the setting of the course in a straight line is 
 guided. This pitching off produces a more uniform effect, and 
 its cost is so trifling that it would require considerable effort to 
 restrain most builders from adopting pitch faced work. 
 
 In this class of work a draft or margin more or less elaborate 
 
16 RAILWAY MASONRY. 
 
 and distinct must be tooled around the four edges of the face, in 
 order to set the work in line and with the proper batter. These 
 guides may be pitched off quite rapidly with the ordinary pitch- 
 ing tool or wide chisel. There is no necessity whatever for work- 
 ing an accurate margin of precise width and exact tool marks. 
 All that is called for is a sharp, well defined edge, by which to 
 gauge the setting of each stone properly in its course. This 
 style of work, as illustrated in the cut of pitch faced pshlar, is 
 rough, jagged and massive, and in appearance is infinitely more 
 grand and imposing than smooth faced work. 
 
 A very beautiful though costly style of work, rarely used 
 except for the corner blocks and tail bonds of the angles of piers 
 and abutments, and then only in such places as to be 
 seen and appreciated, is known as the vermiculated, in which a 
 comparatively smooth faced stone is traversed in all directions 
 by a serpentine net work of deep, sh?rp tool courses, leaving in 
 the spaces between, warty protuberances of some size, which 
 stand out in bold relief to the tool courses. This style of work 
 requires an accurately tooled margin of equal width and depth 
 drawn around all four of the face edges, in order to set it off 
 properly and as though enclosed in a panel. 
 
 A cheaper style of work, which presents a rather elegant effect, 
 is designated the bush hammer dressing. It is used only upon 
 the softer limestones and sandstones, and is produced by a ham- 
 mer into the face of which has been cut several deep channels, 
 crossing each other at right angles. This leaves the vacant 
 spaces prominent : sharp edged teeth of pyramidal shape. The 
 striking of the hammer on the face of the stone, pits the stone 
 with numberless little indentations, which act as a relief to the 
 otherwise smooth face. This style, too, must be provided with a 
 chiseled margin of exact uniformity. In bridge masonry it is 
 
RAILWAY MASONRY. 17 
 
 never used, except for the top or covering course, known as the 
 coping. Its use on some stone is objectionable, as .it seems to 
 loosen it, and in course of time it is apt to scale off. 
 
 The only other style of dressing for railroad work of this char- 
 acter is known as the rubbed face. This is a smooth, plain face, 
 produced by either sawing, ch'seling or rubbing one stone 
 upon the other, as can be seen exemplified at any marble works. 
 Much stone occurs naturally in quarries, with a similar face to 
 .that produced by rubbing, and the dry seams and straight grain 
 combine to make it work out very easily and with straight edges 
 and plain face. . But such a face is very monotonous in its 
 aspect, fully as much so as brick. If. can, however, be relieved 
 by working a moulding, champer or margin around the edges, 
 and beveling the horizontal joints. 
 
 A favorite wayof mine in working the blue flag or the limestone, 
 which is always quarried with smooth faces, is simply to relieve 
 the body of the work with sandstone corner blocks and tail bonds, 
 pitch-faced and with drafted joints. It imparts to the work 
 an air of solidity and massiveness which otherwise would be lack- 
 ing, and the cost of which is trifling. 
 
 No matter what the style of the cutting or of the building, the 
 appearance of the work can be greatly enhanced by neat and 
 tasteful pointing of the joints. The mere flushing of the outside 
 joints is all that is absolutely needed as an adjunct to the stabil- 
 ity of the work, but if cut stone has been used to produce an 
 effect, the additional expense of pointing up should be incurred. 
 For this purpose a mortar of one part cement, one part lime, and 
 two parts very fine sand is used. Flush the joints full without 
 smearing the faces, then draw straight grocved courses through 
 these mortar joints with the point of a steel setting bar or a too 
 made expressly for the purpose. Or if the face of the work be 
 
18 RAILWAY MASONRY. 
 
 smooth, point the joints with the trowel, in the style known as 
 Scotch point, which resembles the puttied bead on the mullion of 
 an ordinary window sash. On rubble work simply strike the 
 joints by drawing the side of the trowel along them, holding it in 
 an inclined position so as to cut a rather wide V-shaped gash 
 of eyen depth and width. But the quickest way to point mason rv 
 of any description, is to smooth the mortar joint with the trowel 
 point, which makes an even wide band, and then draw through 
 it a straight, sharp scratch with the edge of the trowel, or, if pre- 
 ferred, draw two parallel scratches. The neat pointing of any 
 kind of stone work requires considerable time and the exercise 
 of some little skill, and unless the work be of some prominence I 
 make no pretension to pointing up, excepting in very ragged joints 
 which I wish to hide, in which case pointing mortar becomes of 
 as much service as paint and putty to another class of mechanics. 
 
 2 
 
RAILWAY MASONRY. 19 
 
 CHAPTER IV. 
 
 THE FOUNDATIONS. 
 
 All necessary details as to the selection of the stone and its 
 proper dressing having been explained, we will advance a step 
 farther, and considering ourselves ready to begin the construc- 
 tion of an open culvert of some importance, will devote ourselves 
 immediately to the consideration of the foundation, bed, bottom 
 or basis upon which we can safely build our masonry with expec- 
 tation of a very small amount of settlement, and that, in a uni- 
 form manner, without rupturing or breaking the bond of the ma- 
 sonry. 
 
 It is essential, therefore, that we begin our work upon a firm 
 and stable bottom, one which is practically incompressible, as in 
 the case of bed rock, or one which is nearly so, as in the case 
 of firm level beds of clay, or hard, concreted and indurated 
 gravel. 
 
 Every one of my readers has seen great banks of clay, solid, 
 firm, of great cohesion and density, which have served as the walls 
 or con fines of some stream for years. All this time the current is 
 gradually but surely cutting out a deep groove or shelf under 
 the bank. No crumbling or falling away of small masses is re- 
 marked, but at some hour the last hair's breadth in the groove has 
 been cut (like the last bite of the w rm which fells the mighty 
 oak) and the entire bank, in one mass of many tons weight top- 
 ples over into the stream and lies like a great boulder, without 
 fissure or parting, until completely dissolved. Such a bed of clay 
 ie a most admirable foundation for piers and abutments, if of 
 
20 RAILWAY MASONRY. 
 
 
 
 any great extent and depth ; it is so impervious to water as to 
 remain solid and never acquire to any great extent that pasty, 
 semi-fluid consistency obtained by ordinary soils and earths. 
 
 Every one has also noticed great banks of dark, dingy, brown 
 gravel, coarse grained,. full of iron and concreted firmly together 
 with a natural, earthy cement. This withstands the corroding 
 influence of a rapid current even better than the firm, strong 
 clay just mentioned. I have seen such river banks that seemed to 
 undergo no appreciable change ; no marked dissolution or caving 
 was ever noticed ; they were the nearest approach in stability, to 
 solid masonry, that I ever witnessed. Solid beds of this, or even 
 of good thick heavy crust overlaying a treacherous substratum, 
 are excellent foundations for bridge work. 
 
 Beds of loose, disintegrated gravel and of sand are also nearly 
 incompressible so long as confined and prevented from escap-, 
 ing. But as each particle is separate and distinct from the 
 other, utterly without bond or cohesion, it is powerless to resist 
 the action of running water, and any work built upon such a 
 bottom would be undermined by a rapid current unless far from 
 its reach. In addition to thi-^, much sand is of a quick or mercu 
 rial nature ; the mere seeping of water into and through it ren- 
 ders it of a semi-fluid character soft, yielding and treacherous, 
 and consequently such foundations are undesirable upon which 
 to erect bridge masonry. In fact, no matter how firm the ground 
 and river bed upon which a pier is to rest, it must be well pro- 
 tected against anj reasonable chance of scour. The depth of 
 the stratum must be considerable, so that the work can be set 
 well down into it, otherwise artificial means must be resorted to, 
 which are generally an apron or toe of heavy rubble or rip-rap 
 stone cast around the pier, so that each stone finds its own bed. 
 In some instances such a procedure would obstruct the channel; 
 
RAILWAY MASONK?. 21 
 
 if so the mode of founding must be one yet to be described. 
 Bed rock is the only substance secure against scour aud abso- 
 lutely incompressible, and to novices would seem invariably the 
 most desirable foundation, but in actual practice it is often 
 exactly the reverse, It may present an extremely broken and 
 irregular surface, often smooth and water worn whether level or 
 rounded ; in other spots broken into jagged steps and ledges, 
 with numerous cracks and fissures, with a free course for water 
 through them, which renders the labor of leveling the bed quite 
 considerable, the presence of water also making it exceedingly 
 difficult to keep it dry while such leveling is being done. 
 
 But if the natural bottom be really rock, not a mere shale or 
 imperfect formation, no compression or settling need be ex- 
 pected except that from the shrinkage of the mortar joints in the 
 courses of the masonry. Our only necessity therefore is to 
 level the foundation pit so that the masonry can start from 
 a level bed. This must be done by blasting and working off the 
 irregularities on the surface of the rock, or by filling up the 
 fissures and vacuities with a reliable and trustworthy con- 
 crete, or if perfectly secure from scour, as in the case of a 
 fissure, fine well broken stone or gravel well rammed, will 
 suffice. If, however, the expense be too great to start the work 
 from one level, the excavation may be made with a horizontal 
 step or steps, taking care to execute that part of the work which 
 contain^ the greatest number of horizontal mortar joints with a 
 harder setling mortar than those parts where the work is not 
 so high ; otherwise great difficulty will be experienced in keeping 
 the courses of the stonework level, the sett'ement being greater 
 according to the increased numbe'r or thickness of the horizon- 
 tal mortar joints. 
 
 Generally, at a reasonable depth, such natural bottoms are 
 
22 RAILWAY MASONRY. 
 
 found as I have just described. If not, then an artificial bed 
 must be constructed. 
 
 It will therefore be seen that foundations are either natural or 
 artificial. 
 
 To determine upon what manner of foundation our culvert 
 shall be built, it becomes necessary for us, in the first place, to re- 
 sort to a preliminary digging, or if at considerable depth, boring 
 in order to test the bottom. In boring I generally use an ordi- 
 nary two inch wood auger with jointed rods for lengthening it as 
 the boring proceeds. This I work with three feet levers, and in 
 ordinary soils two men will make a boring of twenty or thirty 
 feet in one day. 
 
 But this mode sometimes deceives us in consequence of strik- 
 ing upon a pocket of clay or gravel, or upon a chance boulder, 
 which as future progress is made in the regular excavation dis- 
 closes its true character and makes a change of plans unavoida- 
 ble, as well as an increase of cost. 
 
 As a rule, however, we are safe in forming our conclusions 
 from the indications brought up by the auger. If a natural 
 foundation is found at reasonable depth we can estimate the cost 
 
 ARTIFICIAL FOUNDATION LOGS FILLED IN WITU CEMENT AND 
 PLANKED OVER. 
 
 of the work. If an artificial foundation is advisable we can decide 
 as to its kind. In building culverts in which the height and 
 weight of the masonry are not great, I examine into the nature 
 of the soil of the banks and bed of the stream, and also ascer- 
 
RAILWAY MASONRY. 23 
 
 tain the depth of the bed of the water course. Unless my abut- 
 ment is to set well back into the bank, perfectly safe^from scour 
 and undermining, or is to be protected by a rip-rap toe, I invar- 
 iably set the foundation several feet below the bed of the stream, 
 varying as I find the tendency of the channel has been to deepen 
 or widen from tne scouring of the current. 
 
 At what I think to be a sufficient depth for the starting of my 
 footing course, secure from undermining, I cease the work of ex- 
 cavating. If the bottom of the trench be a hard crust of clay or 
 gravel, overlaying soft earth, or if it is an ordinary loamy soil, 
 not very firm, or peaty and full pf vegetable fibre as in marshes 
 or in any soil which is somewhat soft and compressible, and not 
 firm enough to bear the weight of the masonry and its load with- 
 out some equal distribution of the pressure over considerable 
 surface, I level the bottom, and then lay down timbers or sleep- 
 ers transversely with the excavation, generally using oak ties. 
 These I place eighteen inches apart, filling the vacant places 
 flush with very strong concrete, made of fine broken stone, mixed 
 with equal parts of sand and cement. Upon this bed, longitudi- 
 nally with the excavation, is laid and . spiked a two-inch plank 
 floor, sometimes adding another thickness, which is laid so as to 
 cross the joints of the lower course diagonally, also spiking this 
 layer. This mode makes a very strong bed upon which to start 
 the masonry, and any settlement upon a spongy and compressi- 
 ble soil will be uniform. I have rarely found it necessary to 
 draw back the footing course of stone more than six inches from 
 the edge of the plank flooring, although the greater the extent 
 of flooring the less is the liability of settling. 
 
 Jf the timber is good and the ground wet, which latter is 
 always the case, no fears of decay need be entertained. Under 
 ordinary circumstances, for abutments of culverts this is not 
 
24 RAILWAY MASONRY. 
 
 only the most inexpensive artificial foundation but is also a re- 
 liable one. 
 
 The other artificial foundations will receive due attention in 
 future chapters, the next in course being piling and the circum- 
 stances under which it is advisable. 
 
 It often occurs, however, that the ground is too spongy and 
 compressible to render the artificial foundation just described, 
 advisable. The depth of the soil above the hard stratum may 
 be so great as to make the bringing up of the tolid masonry 
 from it an expensive matter, in which case I proceed as follows: 
 
 I make the excavation a reasonable depth below low water 
 line, say four feet. I then pile the pit, setting the piles from 
 two and one quarter to five feet apart, from center to center, 
 according to the weight of the masonry to be put upon them. The 
 heads of the piles are cut off level some three or four inches 
 beneath low water line ; they are then all connected together by 
 wales or wooden strips, set into shoulders or daps, and spiked. 
 
 This then leaves a vacant space between each four piles some 
 three feet and over in depth. This I fill flush up to the top of the 
 heads with concrete of four or five parts finely broken stone 
 mixed up with a mortar of one part cement and two parts sand. 
 I never use a poor concrete. My object is not to see how much 
 sand I can use or how little cement or lime ; my purpose is to 
 form an artificial stone which adjusts itself to all the knotiy ex- 
 crescences and unequal shapes of the piles, moulds itself around 
 them tightly and closely and in course of time, if well rammed 
 down, hardens into stone as strong and durable as limestone; the 
 piles then really being imbedded into one solid mass of rock, 
 where if movement or settling takes place, all must be together 
 and uniform. 
 
 This is, if properly made, an admirable artificial foundation. 
 
RAILWAY MASONRY. 
 
 25 
 
 Culvert work never requires any better. The illustration shows 
 this method as adapted to an under water foundation for pier. 
 
 PILING FOUNDATION FILLED IN WITH CONCRETE. 
 
 Upon the surface of the foundation just described I step 
 with satisfaction and start the footing course of my masonry. 
 
 Before commencing my excavation I give some thought to its 
 size and shape. These depend upon, first, the amount of protec- 
 tion, if any, needed for the sides of the embankment. Second, 
 thickness of wall requisite to withstand the outward thrust and 
 pressure of the embankment head. 
 
 If the embankment is high the sides will need to be retained 
 by a wing from the abutment proper. A five foot wing extend- 
 ing at an angle of forty -five degrees from the main wall is my 
 favorite, but the stone requires considerable hammer work to 
 shape it for the splayed corners necessary whereas stone for rect- 
 angular corners is much more easily put in shape, for which rea- 
 
36 RAILWAY MASONRY. 
 
 son I generally build rectangular wings. If the stream washes 
 at the foot of the embankment I lengthen the wing at that place 
 accordingly. The higher the embankment the greater the out- 
 ward pressure. I usually undertake to secure a width of two 
 and one-half feet at the finish of my work, upon which the wall 
 plate is laid. In heavy bridge work this same finish at coping 
 should be five to eight feet, but this is sufficient for cul- 
 verts. 
 
 As I do not wish to have the base of my abutment more than 
 four or five feet wide, I vary the batter according to its height, 
 setting back my work as much as one to six for low wall, which 
 is two inches to one foot in rise. I am now working an abut- 
 ment twenty feet in height, in which I batter my work one tc 
 twenty-four, or only one inch in two feet rise. I rarely build 
 any work entirely plumb, because such width of wall is not 
 needed at the finish, but more especially because a battered wall 
 preserves itself better against the pressure of the embankment 
 and is not nearly so easily thrust out of plumb, thereby ren- 
 dering the falling of the work imminent and disastrous to life 
 as well as property. 
 
 All this decided, I am ready to lay out my pit. Unless an 
 oblique work is called for I lay out the face of my abutment 
 proper at right angles with the track. I have had this done very 
 accurately and to the exact hair's breadth, and amply verified by 
 the engineers provided by the company, but as it generally con- 
 sumes two day's time before these gentlemen are sufficiently oat- 
 isfied that all stakes are correct and the crosses on the stake 
 heads in exact position, I weary of the delay and now lay one 
 off in less than half an hour, which, although perhaps not so 
 exact as if done with the aid of instruments, is certainly expedi- 
 tious and sufficiently accurate for all practical purposes. 
 
RAILWAY MASONRY. 2? 
 
 The following cut shows a method of protecting piling with 
 a wrought or cast iron shoe, for driving in hard strata. 
 
 PILING WITH IRON SHOE. 
 
 On the road bed about eight feet back from the face of my 
 proposed abutment, I establish my center. I drive a nail in the 
 tie and with one end of ' a ten foot pole pressed against the nail I 
 rest the other end upon one, of the rails and chalk the spot. I 
 then sweep the pole across to the other rail and chalk it. I have 
 simply described the arc of a circle, and a line drawn from the 
 chalk mark on one rail to the same on the other will be at right 
 angles to the direction of the roadway, and so if the line is car- 
 ried on, which I do by a pole from which I drop down my plumb 
 bob, and drive the stake. This is done on the other side, and a 
 line drawn from stake to stake is rectangular with the stringers 
 above. If the track is oblique I draw lines from the outside of 
 one rail at one end of the opening and extend it to the outside of 
 the rail at the other end. On the other side I draw another line, 
 only using the inside of the rails instead of the outside. Now, 
 
28 RAILWAY MASONRY. 
 
 instead of resting; one end of my pole upon the actual rail?, 
 I mark these strings and obtain thereby a line oblique with the 
 track and in exact degree required. There are other ways of 
 accomplishing the same end, but this suits my purpose best. 
 
 When all is ready to commence my footing course, I have 
 mortar made, composed of one part cement to two of good sharp 
 sand. I use this cement mortar until far above the ordinary 
 water level, when I use lime one part, ashes one part, and sand 
 three to five parts, just as I find the sand requires, for some sands 
 are naturally hungry and require a large proportion of lime. No 
 just rule can be laid down, only this : never let it get above five 
 parts sand to one of lime. The ashes I use because they make 
 the lime mortar set like a cement mortar and impart some con- 
 siderable degree of hydraulic energy to it and render it imper- 
 vious to the moisture, which would otherwise decompose the 
 ordinary lime mortar. Either coal or wood ashes are good, and 
 in their absence brick dust will be found no mean auxiliary to 
 the lime. 
 
 When the work is completed I point up the joints with a mor- 
 tar of one part cement and one part sand, into which is worked 
 one part lime to make the mortar work easily and adhere where 
 thrown. 
 
RAILWAY MASONRY. 
 
 CHAPTER V. 
 
 MANNER OF CONSTRUCTION ABUTMENTS. 
 
 Having taken into consideration the height of embankment and 
 pressure exerted outwardly upon any masonry erected to with- 
 stand this outward thrust, and having decided upon the shape 
 and thickness of abutment, which thickness is also regulated to 
 a great extent by the width of the foundations upon which we 
 are to build, we turn our attention to the masonry. If the work 
 is one of no great importance, if the height of the opening, and 
 consequently the weight of the masonry itself are slight, I care 
 for nothing better than good solid rubble laid in ranges, roughly 
 hammer-dressing the side joints into perpendicular and pointing 
 or picking off any glaring inequalities on the beds ; being careful 
 to lay each stone so that it overlaps the joints of the work in the 
 lower course, and at the same time spalling up any requiring it 
 so as to put it upon a level with the others of the same course. 
 Where the stones do not fit closely I fill the vacuities with broken 
 stone and mortar, which in time become equally hard with the stone. 
 
 SECTION OF WING AND ABUTMENT. 
 
 The general construction of this work is shown in the illustration 
 of footing courses of an abutment with diagonal wings, the 
 
30 RAILWAY MASONRY. 
 
 dotted lines showing about how the joints of the upper course 
 break those of the lower. 
 
 If the work is of still less importance, and the height of open- 
 ing perhaps but four or five feet, consequently needing much 
 less strength, I should face my work with layer stone laid in 
 courses, with occasional headers laid through or at least nearly 
 through the wall, so as to bind it thoroughly. The back I 
 should build of the ordinary rubble or waste rock of my quarry, 
 and fill in between with the same or with a first class concrete of 
 broken stone. If good rich mortar is used in such work, the in- 
 
 ABUTMENT IN- RUBBLE RANGE WORK END ELEVATION. 
 
 tericr of the mass will in course of time become much more solid 
 and harder than any sandstone. No trouble need ever be expe- 
 rienced from it, I have used it as the filling of very heavy bridge 
 abutments and piers, the outside being faced with cut stone and 
 the headers running back and through, resting upon the concrete. 
 Then by the addition of more concrete the header becomes com- 
 pletely imbedded in it and so thoroughly cemented as to fracture 
 through the stone before parting from its concrete bed. For the 
 lower work cement concrete is needed; above that the lime con- 
 crete will answer. In making concretes I simply make up a bed 
 of mortar into which I shovel damp broken stone until the mor- 
 
RAILWAY MASONRY. 
 
 31 
 
 tar can take up no more. I hoe this mass over thoroughly so 
 that each and every stone becomes well coated with mortar, and 
 carry it into the work. This mass eventually becomes a conglo- 
 merate stone of great hardness, and where good stone is expen 
 sive can be employed to advantage, but usually it is more costly 
 than solid stone work. 
 
 As before remarked, in some situations concrete is cheaper 
 than well shaped stone, while in others it is costlier. 
 
 1 vary my modes of construction for the very good reason that 
 I wish my quarry kept clean and free from the waste stone and 
 
 'ABUTMENT IN RUBBLE RANGE WORK VERTICAL SECTION. 
 
 dirt that are always accumulating. The earth which is uncovered 
 from the stone I load upon the cars and set out upon some side- 
 track until I have need of it and I have invariably found occa- 
 sions for the use of earth for filling around my work in finishing 
 up in which case the loaded cars come in very acceptably. 
 
 Again, between the layers of the rock are ledges of shale and 
 shingle, which pick and blast out in very small fragments, and 
 require so little exertion to break up into a size that will pass 
 through a two or three inch ring, that I have had one man re- 
 
82 RAILWAY MASONRY. 
 
 duce an entire car load in one day. This as well as the junk 
 stone I set out and use, because under such circumstances I can 
 do it profitably and at the same time keep my quarry in working 
 shape. It is not from preference that I do so, however, as the 
 company has an excellent crusher located on the road from which 
 I have never asked or received a single car of broken stone. That 
 I prefer large stone is evident from the fact that I use the rub- 
 ble and concrete only in the minor works. 
 
 i Both classes of this work are shown on pages 30 and 31 . All that 
 is necessary to render them worthy of consideration is conscien- 
 tious workmanship executed with tlrst-ciass mortar. From mo- 
 tives of economy their adoption is rarely advisable unless under 
 circumstances similar to those noted, and even then the constant 
 supervision of the foreman is required to see that the work is 
 well executed. 
 
 Upon most American roads masonry is a secondary matter and 
 is generally built after the road has been opened. When first 
 constructed piling and timber are freely used, but the road being 
 put in operation then comes the substitution of masonry under 
 all manner of drawbacks and obstacles. The stone must either 
 be unloaded along the track at some distance from the work, 
 upon a level grade, or put upon the side of some steep em- 
 bankment at the work and also scattered in the dry bed of 
 the stream. The dirt from the excavation becomes quite a hin- 
 drance, and the piles, bents or struts interfere greatly with the 
 free working of the derrick. 
 
 The sand pile, mortar beds, water barrels, material, etc., all 
 combine to make everything crowded and inconvenient. Sand, 
 perhaps, must be brought from a distance ; even the stream may 
 be dry and water must be pushed on a car from some other stream 
 or taken from the tank of some passing locomotive. Considera- 
 
RAILWAY MASONRY. 3S 
 
 ble allowance must therefore be made for such loss of time. Be- 
 fore beginning the excavation the track must be well protected 
 from any danger which would ensue from the caving in of the 
 embankment, which always happens more or less. This protec- 
 tion is afforded by putting in additional lengths of stringers which 
 reach well back upon the embankment and which can be upheld 
 near the excavation by bents or a crib of ties, so that the work 
 can go steadily on without holding trains or delaying the work 
 until they have passed over. 
 
 The mere building of the stone work generally occupies much 
 less time than making ready for it and finishing up afterwards, 
 and it is essential that such masonry should be built so as 
 to be permanent, that all the confusion and expense may require 
 no repetition. The entire matter is one needing the exercise of 
 considerable judgment. There are cases where an excellent ma- 
 terial foundation can be found at very slight depth, where there 
 is no danger whatever from scour, and where the excavation of 
 deep trenches would be a waste of money. There are others 
 where the embankments need walling up with heavy wings or 
 strong retaining walls. In some cases these wings should extend 
 in height almost to the top of the grade: in others their height 
 jneed be inconsiderable and the edge of the embankment should 
 rest upon the tops of the wall, such being then a surcharged 
 retaining wall. 
 
 Again, very often the sides of the embankments require no aid 
 whatever in the form of stone work, or perhaps at most require 
 tome loose rubble thrown along their base. In fact, what will 
 answer in one situation will not in another. In one an open cul- 
 vert is preferable, in others a box or an arched culvert is bet- 
 ter, and these we will next consider. 
 3 
 
34 RAILWAY MASONRY. 
 
 CHAPTER VI. 
 
 BOX AND ARCH CULVERTS. 
 
 A box culvert is one provided with a flat roof or cover of stone, 
 reaching from one wall or pier to another parallel wall and rest- 
 ing thereon. Such opening is of necessity narrow, and unless 
 unusually long and heavy stones are used it can rarely ex- 
 ceed four to six feet in width, as it must be remembered that 
 the covering stone's must lap over upon the piers which sustain 
 them. The embankment must also be of considerable height, 
 for it is absolutely necessary that at least two feet of earth shall 
 rest upon the roof between it and the ties. This earth acts as a 
 cushion in softening the shock of a passing train. In the 
 absence of a sufficient layer of earth the roof would be broken, 
 not from the weight of the train but Irom the repeated ham- 
 mering blows of the wheels. 
 
 The excavation for a box culvert should include not only the 
 space to be occupied by the walls or piers but also all the inter- 
 mediate space between. The bottom should be brought either 
 to a uniform level or hollowed out in the centre from end to 
 end and paved with good large stone that will not be washed 
 out by the current. 
 
 The two sides of this pavement will serve as footing courses 
 for the walls of the culvert. The covering should be of rectan- 
 gular stones fitting closely together, so that in case the embank- 
 ment is high each stone need bear only the weight of the earth 
 directly above it. In general too little care is taken with this 
 class <)f work. The excavation is made very slight, the culvert 
 bottom often being considerably above the surface of the adja- 
 
RAILWAY MASONRY. 
 
 35 
 
 cent land, making drainage impossible but complaint from the 
 land owner certain and earnest. 
 
 The roof is often made simply of several long stones laid a 
 foot or more apart, like the rafters of a timber roof, and across 
 from one stone rafter to the other is laid any rubbish in the shape 
 of stone that will cover the space. As a consequence each long 
 stone must support not only the weight of earth directly over it 
 but also that over the stones that lap from it to its fellow. In 
 
 BOX CULVERT, WITH PAVEMENT. 
 
 the case of a heavy embankment such additional weight often 
 proves too much and breaking in of the roof takes place, and in 
 order to repair this damage an excavation perhaps twenty or 
 thirty feet or more in depth must be made to get at the work 
 and rebuild it. 
 
 Such work should I e well built ot heavy stone, and every pre- 
 caution should be taken against breaking in of walls or roof. I 
 lately built a double culvert, one chamber of which was com- 
 posed of only seven stones in its two walls and nine in the roof. 
 
86 
 
 RAILWAY MASONRY. 
 
 The extreme size ami weight of these stones made them slow and 
 tedious to handle, but the strength and permanence of the work 
 amply compensated. Diagonal wings are essential to the entrance 
 and also to the exit, and the space between should be paved, so 
 that no holes can be worn by the rush of the water, which would 
 
 (Ws*r/:s.- ^^xx^xx^^-xx//////.///-/^/"".^.. . ^T^y..^ NW w^-vxxxxxxxJS 
 
 ARCHED CULVERT OF CUT STONE. 
 
 form eddies resulting in the undermining of the culvert proper 
 and perhaps wearing a passage under the floor or along its sides, 
 preparing the way for a washout. 
 
 A costlier and more important class of work is known as the 
 arched culvert of which a sketeh is shown below. In this, a a 
 ere the impost stones or tops of the piers from which the arcb 
 
RAILWAY MASONRY. 
 
 87 
 
 springs. The distance between these is called the span of the 
 arch. The height from the level of the imposts up to the key- 
 stone b is called the rise of the arch, the inside curve *is the sof- 
 fit, while the outer or upper curve is called the extrados and 
 each stone which is a member of the arch is designated a voussoir. 
 
 Before building an arch a timber framing or centering is put 
 into position, and commencing at the imposts the voussoirs are 
 laid upon this framing until all the keystones are inserted, which 
 bind the work together so that the framing can be removed. 
 
 In this class of work accurately dressed stone should be used, 
 not only in the arch itself but also in the piers. A reliable and 
 uniform foundation is the onfy kind upon which such work should 
 
 v. 
 
 
 
 
 < j^t?i/i 
 
 l^TxJl 
 
 ENGLISH BOND EVERT ALTERNATE COURSE HEADERS. 
 
 be started, as any sinking of the haunches will tend to settle the 
 lower courses of the arch and spring the voussoirs away from 
 the keystones, weakening the arch and quite likely causing it to 
 fall in. For this reason dressed stone should be used in the 
 piers. Again, in the arch rubble stone could be used, but on 
 account of the shape of the undressed stone much mortar will be 
 required. This of course fills up all vacancies and irregularties, 
 and acts as the key or wedge which holds the work together. 
 
38 
 
 RAILWAY MASONRY. 
 
 Now let this mortar decompose, soften, crack and fall out to any 
 appreciable extent and the work must fall, because that which 
 tightened it and held it together is gone, just as knocking out the 
 wedgef from a lot of blocking will loosen it. 
 
 The better plan is to cut the voussoirs into exact shape and 
 rely upon this shape to uphold the arch and use only so much 
 mortar as is necessary to cement the work together. On account 
 of this accurate dressing, brick is now more frequently used than 
 stone in the construction of arches, and where much of this class 
 of work is to be done, instead of using the ordinary rectangular 
 
 HORIZONTAL SECTION THROUGH WALL. 
 
 (Showing headers running through the wall, and stretchers lengthwise 
 with the wall.) 
 
 brick, beveled ones should be made, the arches being shaped to 
 suit the bevel of the bricks let the result be an eliptical, semi- 
 eliptical, gothic or any other form of arch. 
 
 In former days many expensive stone bridges were constructed 
 with arches of almost incredible span. The railroads of to-day 
 find iron bridges resting upon stone piers preferable, and beyond 
 culvert work, very few arched water ways are now built and these 
 only where the height of the embankment makes them cheaper 
 than open culverts. Therefore, little if any more need be said 
 concerning them. 
 
 We will now turn to that class of work wherein not only all 
 the difficulties of founding the piers of culverts are experienced, 
 but where the presence of water acts as an additional obstacle 
 
RAILWAY MASONRY. 39 
 
 where some mode of protection must be adopted against this 
 troublesome element. The artificial foundations already illus- 
 trated can be used f r tie abutments and piers of heavy bridges, 
 but when such work must be set in the bed of a stream, coffer- 
 dams, caissons, etc., are needed so that the foundations can be 
 kept comparatively dry while the work progresses. 
 
 In the accompanying illustrations the manner of laying the 
 stone is shown. The English bond is considered the strongest 
 although either style will be found sufficiently massive if built up- 
 on a proper foundation. We are, therefore, left very little to con- 
 sider but hydraulic foundations in future articles. 
 
40 RAILWAY MA.SONBT. 
 
 CHAPTER VII. 
 
 HYDRAULIC FOUNDATIONS 
 
 In carrying out the construction of bridge masonry over water 
 courses of considerable size, in addition to the difficulty often 
 experienced in obtaining good foundations, we encounter another 
 great obstacle in the form of water. Various means must be 
 adopted to make this drawback as inexpensive as possible. Every 
 river bed may present some peculiarities of its own, or some com- 
 bination, differing from all others, and it is these that must gov- 
 ern us in the modes of working. In one place we may use piling 
 or sink caissons for foundations; in other places we may bring 
 up solid masonry from the natural bottom, executing the work 
 with the aid of the diving bell, or we may construct a cofferdam 
 around the site of the work, and the interior being pumped dry, 
 we can carry up the masonry above the level of the water line, 
 when there is no further need of the dam. However, I will enter 
 into no theoretical disquisition upon the matter, nor will I at- 
 tempt to classify the various modes of founding and the circum- 
 stances which make them most desirable. I will, instead, ex- 
 plain my views much better by entering at once into actual prac- 
 tice, wherein the features of the river bed, banks and current 
 are varied. 
 
 I wish to build the abutnients and four piers for a bridge to 
 span a certain wide stream as shown in the illustration. The 
 site of the first abutment is back some fifteen feet from the edge 
 of the water at its usual stage, in a heavy bank of stiff, shelly, 
 blue clay which rests directly upon the bed rock some thirty feet 
 below ordinary water level. 
 
41 
 
 The first pier is located 
 in ten feet of water, over- 
 laying 20 feet in depth of 
 mud and hard clay, and is 
 somewhat apt to scour in 
 time of freshets. 
 
 The second pier is to 
 be built at a point where 
 the bottom is perfectly * 
 smooth, level rock with 
 a depth of water of some 
 thirty feet the current 
 being here extremely 
 swift and often carrying 
 considerable quantities of 
 driftwood and ice. 
 
 At the third pier the 
 level ledge of rock has 
 terminated the bottom 
 is extremely rough, with 
 broken bed rock, at a 
 depth of fifteen feet. 
 
 There may also be a 
 fourth pier (not shown in 
 the illustration) rising 
 from a small island or 
 bar of mud and silt of 
 semi fluid character, ten 
 feet in depth. 
 
 The remaining abut- 
 ment will be built in the 
 
42 RAILWAY MASONRY. 
 
 water's edge upon hard level rock only three feet from the 
 surface. 
 
 Commencing with the first abutment I excavate my pit to 
 a depth of about twelve feet from the surface nearest the water, 
 encountering no trouble from that element, except from the 
 small quantities which seep in through several slight seams in 
 the clay, on account of which I am compelled to pump out and 
 sheath the entire work on one side with planking, behind which 
 I ram down a casing* of cement which cuts off almost all the 
 water. At this depth I decide to commence the masonry, not 
 thinking it necessary to carry the excavation down to the bed 
 rock, because the pit is so far back from any danger of scour 
 from the current that any further expenditure would be uncalled 
 for. I would like to have set the masonry directly upon the clay 
 or upon a light bed of cement concrete, but the leakage of water 
 into the work has so softened the bottom of the nit that I make 
 use of timbers laid transversely with the trench and filled in be- 
 tween with concrete and planked over, as has already been illus- 
 trated in one of the chapters on culvert work. As each course 
 of masonry is laid I pack the space between it and the sides of 
 the pit with well puddled clay, which I see is well rammed down. 
 The masonry is then carried up in cement mortar nearly or quite 
 to the finish in the mode already explained. 
 
 This is not therefore properly a hydraulic foundation, but in 
 the execution of the first pier I find my work must be carried 
 uv through twenty feet of stiff clay and mud, over which flows 
 at ordinary stages some ten feet of water. At considerable ex- 
 pense I could build a cofferdam around the site of this pier, and 
 either start the masonry from the bed rock or set it down in the 
 clay, as with the first abutment, but I do not desire to go down 
 to the bed rock on account of the cost; and again, on the other 
 
RAILWAY MASONRY. 43 
 
 hand, I notice some little evidences of scouring which create 
 doubt in my raind as to the permanency of any work merely set 
 down into the clay, as it would evidently stand in danger of 
 being undermined sometime. Therefore as the clay and mud 
 are sufficiently dense to hold up in the perpendicular any piles 
 that I might drive, I put in a pile foundation such as already 
 shown in a previous chapter on culverts. 
 
 Bed rock being within easy reach of a thirty foot pile, instead 
 of using short piles, which would penetrate only a part of the 
 depth of the clay, I make use of those which will strike the rock 
 and act in reality as posts, in which case, provided the piles are 
 of sufficient strength, no settlement in the pier would be visible 
 except that caused by slight shrinkage of the mortar in the hori- 
 zontal joints of the masonry. But were the bed rock at much 
 greater depth I would not drive the piles with the intention of 
 resting them as in this case upon the solid rock. 
 
 Elaborate tables have been prepared by eminent authorities by 
 which we are supposed to determine the safe load a pile can carry 
 ras for example, " the force of the blow by a ram of certain 
 weight falling a certain distance being given, to find the dead 
 weight or pressure which the pile would sustain, etc." But in 
 actual practice these formulae and rules often prove sadly defi- 
 cient in accuracy, for in the majority of these tables the calcula- 
 tions assume the soil to be homogeneous or of the same nature 
 from top to bottom, whereas in reality there often occur cases 
 where the piles pass through strata of alluvium, shale, clay, sand, 
 hard pan, etc., and although they may resist the hammer, it 
 is sometimes difficult to determine how much of this resistance 
 is due to mere lateral friction, and how much to a hard stratum. 
 
 The better way in starting such work is to drive a test pile or 
 soin order to determine, if possible, the required length for the 
 
44 RAILWAY MASONRY. 
 
 regular foundation. Generally a pile should be driven until 
 it will not sink more than one inch under the last blow of the 
 monkey. Piles have been driven only twenty feet in stiff clay 
 and sustained a weight of eighty tons, but not more than one- 
 quarter that weight is often required to be upheld by any pile, 
 and in mud and marsh bottoms care must be taken to drive 
 it sufficiently deep so that the lateral friction alone can be re- 
 lied upon to offer considerable resistance to the sinking of the 
 pile under a reasonable amount of dead weight. Foremen of 
 the pile drivers, if experienced, generally know best about 
 the soils and bottoms along the line of the road which employs 
 them. They have generally some pretty clear ideas about what 
 manner of deposit the pile is penetrating know when the pile 
 has set and are quite apt to be very positive when they have struck 
 solid rock, and their judgment can generally be deferred to with 
 a conviction that they are not very far out of the way, if at all. 
 In passing through some strata it is often necessary to ring 
 the heads of the piles with iron bands or rings, to prevent split- 
 ting the piles under the blows of the hammer, \lso to shoe the 
 points with cast or wrought iron, sawing off the extreme point of 
 the pile, and making a shoulder or socket in the iron shoe into 
 which this sawed off end will fit. Such a shoe will stand consid- 
 erable heavy driving though much resistance be offered. If, 
 however, the pile is sharpened down to a point and the iron fits 
 close to it the sharp point will act as a wedge and split the shoe. 
 But I will return to the pier. When all the piles are driven 
 they are cut off to a uniform level several inches below the low- 
 water line, the spices between perhaps left open to the water or 
 closed up by sheet piles, between those piles forming the sides of 
 the work, and the interior vacancies filled up with broken stone, 
 or under some circumstances, with cement concrete; timbers are 
 
RAILWAY MASONRY. 45 
 
 then laid upon tbe tops of these piles and planked over as a plat- 
 form on which to lay the masonry. The piles must be cut off 
 sufficiently low to place all the woodwork permanently under wa- 
 ter in order to prevent decay. If a cement concrete filling is 
 used considerable additional expense must be incurred in order 
 to prevent the washing out of the cement before it has set suffi- 
 ciently to withstand the water, therefore, I rarely use it in such 
 situations but adopt another method, as will be shown in piers 3 
 and 3. 
 
 The second pier of this bridge must be founded upon a smooth 
 level bed of rock, lying at the depth of thirty feet below t he- 
 usual stage of the water line. The surface of this rock is water 
 worn and smooth from the action of a powerful current Avhich 
 prevents any lodgment whatever of sediment, mud or sand. The 
 illustration already given shows the site of this pier in the bot- 
 tom of a ravine or wide fissure in the river bed, forming its chan- 
 nel, through which is carried much driftwood, not only upon the 
 surface but also partly or entirely submerged. A large body of 
 such float striking and pressing against a pier merely setting 
 upon this smooth level bed rock without fastening of any kind, 
 Tvould be very apt to slide it out of position, and in our work we 
 must take some precautions against this danger. It is desired 
 to build the superstructure with spans of uniform length, other- 
 wise the pier might be located back farther in a less exposed 
 position. 
 
 Piling is entirely out of the question because of there being 
 no soil into which piles could be driven. I find the current so 
 strong that a man in diving armor can do nothing unless 
 its force is diverted. The only feasible plan is to con- 
 struct a caisson or huge chest either with or without bottom. 
 The natural surface of the rock being smooth and level, the ex- 
 
46 
 
 RAILWAY MASONRY. 
 
 pense of a timber bottom to the caisson is unnecessary. In fact 
 these bottoms are never advisable or needful except in two situ- 
 ations : where the caisson is to be set upon piling, or where 
 we are building upon marshy or peaty ground of great depth, into 
 which we expect the caisson with the masonry inside to sink until 
 it compresses the soil under it so as to suspend the caisson in its 
 midst, or allow it to settle down uniformly until it eventually 
 touches hard pan or some other tirm stratum, of which I shall 
 fully treat hereafter. 
 
 END SECTION OF CAISSON. 
 
 A caisson with timber bottom must rest upon a uniformly 
 level surface, for if it is deposited upon a firm stratum of uneven 
 surface, some parts of the bottom timbers will be unsupported 
 and experience severe cross strain, which will in time surely lead 
 to very serious fractures in the masonry. Then again, if placed 
 upon any soft soil that becomes exposed to the current, the work 
 will be undermined and dangerous, and breaks will occur. If the 
 bed be smooth, level and hard, we do not need the timbered bot- 
 tom, because we can by a little scribing of the lower edges of the 
 sides and ends of a bottomless caisson place it so well in positioD 
 
RAILWAY MASONRY. 47 
 
 that with the aid of cement concrete we can make it almost per- 
 fectly water-tight. Therefore on the shore we construct the 
 sides and ends of the caisson in panels or sections so'as to be de- 
 tachable after our pier shall have been completed. From two to 
 four inch plank will suffice, according to the force and depth of 
 the stream in which it is to be placed. The cross and upright tim- 
 bers should be from four to six inches in thickness. These sides 
 and ends can be erected upon ways which slope from the shore 
 to some distance into the water at such depth as will float the 
 caisson off the ways, when it can be towed out to its loca- 
 tion and sunk by swinging rails on to the sides near the lower 
 edges, these rails being drawn up again when the caisson is no 
 longer needed. 
 
 The trouble of properly locating such a caisson is not so great as 
 may be imagined. Any body under water can be moved with 
 much greater ease than when above ground. While sinking, it 
 can be held well in position by ropes made fast at the corners 
 and can be shifted by them or moved around on the bottom by 
 men in diving helmets. 
 
 Our caisson is put up in one piece, well caulked with tow and 
 located upon the bottom. Our next move is to form a water tight 
 floor upon the bed rock inside the caisson walls to stop off the 
 bottom water and allow us to pump out the caisson and begin 
 the masonry. In order to accomplish this, we deposit a layer of 
 cement concrete only one foot in depth. Should we bring our 
 flat boat alongside the caisson and shovel the concrete into the 
 caisson before reaching the bottom in passing through the 
 water, all the cement would be washed out and separated from 
 the sand and broken stone forming the concrete, thereby render- 
 ing the concrete worthless. We therefore lower it by means of a 
 box holding one cubic half yard, this box having a hinged bottom 
 
48 RAILWAY MASONRY. 
 
 whereby we can deposit the concrete immediately upon the bed 
 rock and in the water so near the bottom as to cause no percep- 
 tible disintegration. The box being emptied quickly rises 
 to the surface to be returned as before. We make use of 
 strong concrete of one part cement to one part sand, with 
 such amount of broken stone a? can well be incorporated with it. 
 The edges of tie caisson fitting closely lo the rock, there is in 
 consequence but little scouring out of the concrete. Not wishing 
 to injure it by the disturbance of the pumps we let it rest and in 
 three days time it is thoroughly set and the caisson is pumped 
 dry when we find the layer of concrete does not present a uni- 
 form surface and is set so hard that we are compelled to point it 
 off before commencing the laying of the stone upon it. 
 
 The current seems to exert all its force to shift the caisson, 
 weighted as it is with the iron rails, and we begin to realize the 
 danger in which our pier would be placed in time of freshet. 
 Therefore we drill through the layer of cement eighteen inches 
 into the bed-rock, drilling four rows lengthwise with tlie base of 
 the pier, and at distances of four feet apart in tlie'rows. In 
 these drill holes iron dowell pins four feet in length are inserted 
 and leaded, the ends above the concrete layer which enter drill 
 holes in the stones of the footing course of the masonry being also 
 leaded. The cut shows the footings of the pier and the shape of 
 the work with projecting base resting upon the footings. From 
 this base the pier is built up with a cutwater of smooth, dressed 
 Btone. well bonded into the heavy portion of the pier, being 
 gradually drawn in until it is merged into the pier at five feet 
 above high water line when both ends of the pier are brought to 
 a point in the form of circular arcs, having a radius of about 
 three-fourths the width of the pier. 
 
 In pier No. 3 the bottom lies upon the cropping out of 
 
RAILWAY MASONRY. 
 
 49 
 
 several ledges of rock, very rough and broken. We here sink 
 a bottomless caisson, whose lower edges we mast scribe to a con- 
 siderable extent so as to fit to some degree the irregularities in 
 their surface. A diver must be sent down to work off 
 some of the most prominent projections and fill up the fis- 
 sures with rubble stone: but in spite of all this we cannot fit the 
 iides of our caisson closely to the rock. We therefore line it 
 with canvas with a rather baggy bottom, sink it into position, 
 and deposit our concrete within the sack, which adapts itself suf- 
 
 ^c^l 
 
 FLEMISH BOND HEADERS A.STD STRETCHERS ALTERNATELY, IN 
 EVERY COURSE. 
 
 ficiently well to the surface : then we proceed as related in the 
 case of the second pier. This canvas bottom is a protection 
 for the concrete, as it would otherwise be washed away by the 
 current which would enter between the caisson and the rocks, 
 and would scour out nearly if not quite all of the concrete. 
 
 If there is to be a fourth pier (not shown in the cut) on a 
 bar of silt ten feet in depth, we again use the bottomless caisson, 
 which we sink with rails, dredge out and put in a canvas bottom. 
 Were this island composed of strong earth that would sustain 
 sheet piling, we would erect a timbered cofferdam, or were the 
 
3V RAILWAY MASONRY. 
 
 bed of silt only one-half so deep, we could surround the site 
 with a cofferdam of clay. The second abutment of our work 
 is to be located in the water's edge with a depth of only three 
 feet to bed-rock. A clay bank being right at the work, our cof- 
 ferdam is constructed of this. Two sluice boxes are put in so that 
 the enclosure can be flooded with water at any time that a freshet 
 is apprehended, and prevent any breach in the dam. 
 
 A cofferdam is an enclosure built around the site of the work 
 for the purpose of pumping it out and keeping it dry 
 
 JSNOLISH BON3> ONE COURSE ENTIRELY OF HEADERS', NEXT 
 ENTIRELY OF STRETCHERS. 
 
 while masonry is under way. It is necessary that these en- 
 closures be as nearly water-tight as possible. They are only 
 adapted to depths of less than twenty feet, and the material of 
 which 'they are constructed must depend not only upon the height 
 of the dam required to keep out the water, but also on the char 
 acter of the bottom. There are situations, as in case of our pier. 
 No. 4, where cofferdams are not advisable, although the depth 
 of excavation is not great. Very high cofferdams of* earth are 
 expensive, considerably more so than timber dams, but in slight 
 depths they are often the best, cheapest and most expeditlously 
 
RAILWAY MASONRY. 51 
 
 constructed. In still water, less than seven or eight feet deep, 
 tarred canvas well weighted at the bottom will answer every 
 purpose if stretched tightly and secured to piling. 
 
 But the cofferdam most generally built is one of either a sin- 
 gle or double row of piling, the first piles being the guide pilea 
 driven in a row at intervals of about ten feet. If the depth 
 is not great nor the current heavy, we may use only one row of 
 piles: therefore, on each side of these guide piles, at the top and 
 as near the bottom of the excavation as possible (see illustration), 
 we bolt timber strips or wales, horizontally, and down between 
 these wales we drive sheet piling, each joint as close to the other 
 
 BASE OF PIER, A3 BUU-T WITHIN THE CAISSON. 
 
 as it can be driven, so that buv. little caulking need be done to 
 make the joints water tight. Two- inch plank is sufficiently 
 heavy sheet piling for some situations ; in other instances square 
 timber of six inches up to twelve in thickness may be required, 
 according to the depth and pressure of the water. But in works 
 of any consequence a double row of such piling is better, set 
 with a width of at least one foot vacant space between, which 
 we fill and ram down as it is being filled, with a well-worked 
 mixture of wet clay and gravel, which is better and forms a more 
 impermeable filling than clay alone. The depth to which these 
 piles must be driven is only so much below the bottom of the 
 work as will give them power to stand perpendicularly until 
 
52 RAILWAY MASONRY. 
 
 the work is braced from the top and also to prevent them from 
 being pressed in at the foot by the head of water and soil. I 
 have seen cases where a driving home of only three feet proved 
 an excellent dam, which withstood a head of water of seven feet, 
 although I wish it remembered that the tops of piles were braced 
 from the inside. 
 
 But these piling dams cannot always be used, it being as impossi- 
 ble to obtain a foothold for them in soft mud. as it would be on 
 rock bottom. So there are then two situations where piling is of 
 no advantage. If the depth is too great for a clay dam, the only 
 other resort is to make the dam of narrow bottomless caissons, 
 sink them in a line around the site of the work and fill them up 
 with puddled clay and gravel ; but rather than do this most 
 builders wouki prefer some other plan of work. Cofferdams 
 must be adapted in strength to the bead of water and soil whose 
 pressure they must withstand. Generally they must be provided 
 with sluices so that they can be filled with water on the ap- 
 proach of high tides or freshets, as it is better to pump the cof- 
 ferdam out than to have it washed away or greatly damaged. 
 
 Cofferdams can be built upon rock bottoms at slight depths by 
 using iron rods instead of piles. These rods are set into drill 
 holes in rows and planking is laid between them. That they 
 are expensive and not likely to come into general use can be easily 
 seen. 
 
 At great depths cofferdams cannot be used ; neither can the or- 
 tlinary forms of caissons be used in excavations through exten- 
 sive sand bars or great beds of mud. There are many rivers, for 
 instance, the Arkansas, which are choked up with very deep bars 
 of sand, which has been from time immemorial wasuiug down 
 from tae great plains and filling up the original channel of the 
 river, in many places to a depth of forty to sixty feet ; indeed I 
 
RAILWAY MASONRY. 53 
 
 think no bridge could be built over this stream south of Great 
 Bern?, the excavation of whose piers could be less than thirty 
 feet in depth through coarse white sand, so loose that a dredging 
 boat could work an entire year and still not a single cubic yard 
 of excavation be credited to its account, unless the water was 
 at a very low stage. 
 
 The Platte is a similar river, all of whose bridge piers have 
 been put in by the pneumatic process, at great expense, and in 
 
 PILING COFFER-DAM. 
 
 Two rows of sheet piles (5) driven between horizontal wales (a) which 
 are bolted to guide piles; c is the clay puddle or filling; d is the 
 brace on inside of work. 
 
 some instances with considerable loss of life. The Missouri and 
 Mississippi are rivers whose deposit is not sand but mud. Upon 
 them also the compressed air process is used, attended by great 
 loss of life. On the St. Louis bridge, under a pressure of three 
 atmospheres, several men were paralyzed or died, and the working 
 hours per day were gradually reduced from four hours to one. 
 Of this system I know nothing from experience. I cannot treat of 
 it therefore, but will illustrate a sinking caisson which I have 
 used, and which can be gradually sunk to any depth and which ia 
 
r-4 
 
 RAILWAY MASONRY. 
 
 eminently adapted to work in great depthsof mud or sand. The 
 only obstacle to its perfect working is the encountering of a large 
 snag or boulder, but these do not often occur in actual practice. 
 If any doubt is entertained, several borings can be made over the 
 
 I 
 
 site ' of the work. Any slight obstruction need not deter us in 
 the use of this caisson, as the dredging chambers afford consider- 
 able sccpe for working: away any small snag or boulder. 
 
 This caisson is made in two portions, the bottom having of 
 course four sides, some five to ten feet high, built of timbers in 
 such shape as to make the top portion of each side some three 
 to ten feet wide, from which it tapers down to a cutting edge at 
 
RAILWAY MASONRY. 55 
 
 the bottom, which Is shod with iron. These four sides are 
 cut up by the addition of other walls built exactly the same. In 
 the cut I divide the caisson lengthwise into two eoual parts, then 
 transversely I divide it by five partitions of similar construction 
 into altogether twelve compartments. The bottom of the cais- 
 son is now ready for building upon it the upper portion, the 
 outer sides being constructed as in other forms of caissons, with 
 the exception that parallel to these sides, upon the outer edge of 
 the head of the wedge shaped bottom, is built a stout plank lin- 
 iug extending up to the top of the caisson, so as to form a hol- 
 low wall around all four of the sides. Up from the heads of all 
 the cross partition wedges are built hollow walls with perpendic- 
 ular sides. This, therefore, gives us three long compartments 
 two at the ends, and ten cross sections, whose bottoms are the 
 timber heads of the wedge shaped sides and partitions. In the 
 intervening space of the interior of the caisson we have twelve 
 other chambers which are entirely open at the bottom and whose 
 sides are perpendicular in the upper portion. After that, in the 
 lower portion, the sides flare open towards the bottom cr mouth, 
 this flaring shape being given by the wedge shaped sides and 
 cross sections. 
 
 When all is ready the caisson is located over its site and the 
 compartments within the hollow walls are filled with concrete, 
 timbers being laid in lengthwise with each wall every six feet, 
 so that those in the transverse sections will cross over those 
 in the lateral walls anil bind the various columns of concrete to- 
 gether. As the concrete filling takes place the edges of the 
 caisson bottom cut into the soil and the work continues to 
 sink until some little time after all the closed chambers are full 
 of concrete. The caisson can now be weighted with rails 
 and sunk still deeper, or we can at once commence dredging 
 
56 RAILWAY MASONRY. 
 
 through the chambers which had no bottoms and wt'.ch were de- 
 signed as dredging shafts. As the caisson sank from the weight 
 of the concrete, the wedge shaped sides to the mouth of each 
 chamber pressed the soil in towards its center and on up the per- 
 pendicular shaft. A caisson, say forty feet only In length, with 
 fifteen chambers of concrete, each chamber being five feet in 
 width, must cleave the mud or sand through which it passes to 
 considerable extent, when we reflect that the twelve dredging 
 
 SINKING CAISSON. 
 L.O irer section, showing dredging chambers and concrete compartments. 
 
 chambers not nearly so large as the concrete compartments re- 
 ceive into their funnel shaped mouths and for some distance up 
 each dredging shaft all the soil that was under the entire caisson. 
 This it does and brings it into easy reach of the dredger. In 
 such a caisson the builder can proportion it to suit himself. He 
 must have sufficient storage room for such amount of concrete 
 as will weight the caisson, so that it will sink as the dredging 
 goes on. He must allow in the dredging chambers ample scope 
 for the dredger to operate. He must weight the caisson with 
 the concrete so that it sinks evenly, and in the dredging take the 
 same care and try to sink the work as uniformly as possible. 
 When the bottom is reached and the chambers all dredged out 
 they should be filled with concrete to the top, level in all the 
 compartments, when the masonry should be started thereon. 
 
RAILWAY MASONRY. 57 
 
 CHAPTER VIII. 
 
 CONCRETE WORK. 
 
 Along the lines of some railways, procuring stone suitable 
 for the general purposes of railway masonry is attended with 
 so much difficulty as often to render its use practically impos- 
 sible, but sand, gravel or rough stone is more or less abund- 
 ant in every locality and either of these or all three, combined 
 with the proper proportions of hydraulic cement and water, well 
 incorporated with each other, can be used as a substitute for 
 stone work and can be run into timber moulds or frame work 
 and adapted to all forms of masonry construction with success. 
 
 The excellence of concrete depends greatly upon the materials 
 which are used in its composition in combination with the cement. 
 Sanol can be used alone, but as the proportion of this should not 
 exceed three parts to one of cement, the bulk of the concrete 
 would be so small that it would be found to be very expensive, 
 especially when fully as good, if not better conglomerate can be 
 made by the addition of at least five parts of gravel or broken 
 stone: in fact, all that is required is a sufficient quantity of the 
 bonding material (that is, the cement mortar) to unite the vari- 
 ous particles of stone or gravel. The closer these particles can 
 be made to adjust themselves the less bulk need be occupied by 
 the bonding substance in order to form a solid mass. Small 
 angular stones if pressed together will adjust themselves more 
 compactly than ordinary rounded gravel stones; but when loosel} 
 dumped in a heap the interstices among the angular stones are 
 much larger than in the gravel whereas the gravel such as is 
 often used in roofing when tipped into a heap will settle itself 
 
58 RAILWAY MASONRY. 
 
 into as great compactness as it is capable of. The ramming 
 of clean gravel, instead of being beneficial, tends to displace the 
 various members without bringing them into more compact re- 
 lation. If we use for bulk neither gravel nor broken stone but 
 shingle stone, which, as its name implies, is in flat, thin pieces, 
 and being neither angular nor rounded, can be packed with con- 
 siderable advantage as the mass of concrete is being put into the 
 moulds. Concrete walls in buildings possess one great advantage 
 over either brick or stone in being more porous than either of these 
 and a very poor conductor of heat or cold. They show no frost 
 on the inside in the winter and are drier and cooler in the sum- 
 mer. In ordinary building the concrete walls should be of some- 
 what less thickness than brick walls, and far less than stone. I 
 
 CONCRETE ABUTMENT, FACKD WITH CUT STONE. 
 
 here introduce an illustration of an abutment proper, not a mere 
 shore pier, but a work that actually abuts upon the embankment 
 and not only upholds the superstructure, which a shore pier does, 
 but also acts as a retaining wall in supporting the embankment 
 head, which a shore pier does not do. This work is faced with 
 cut stone, although concrete, moulded into blocks would answer 
 equally well. The courses of cut stone were laid up only one or 
 two in advance of the concrete backing, this stone facing there- 
 
RAILWAY MASONRY. 59 
 
 lore acting as a mould for the concrete rendering timber shut- 
 ters or frames unnecessary. The excavation for the foundation 
 was made with a level floor, into which huge saw-teeth cuttings 
 were made so as to more fully insure the stability of the abut- 
 ment and its power to withstand the heavy outward pressure of 
 the embankment, for while concrete is header than earth and 
 less liable to slip when used in retaining walls or embankments, 
 yet in no case will its weight equal the same bulk of stone similar 
 to that of which it is partly composed. Concrete varies in weight 
 according to the density of the stone which enters into it, 120 
 Ibs. per cubic foot being about a fair average, while 96 Ibs. is a 
 large allowance for earth. Its value as a material for retaining 
 earth embankment is therefore readily seen. But When we 
 compare it with basalt weighing 180 Ibs., or granite weighing 
 165 Ibs. to the cubic foot, ample reason can be seen for the in- 
 creased bulk which concrete must occupy in order to resist as 
 much pressure as the same weight in solid stonework. The pre- 
 cautions shown by the shape of the work are therefore explained. 
 I have already dwelt upon the making of concrete and the care 
 that must be taken not to separate the cementing substance 
 from the other ingredients by dumping from any splashing height 
 or through water. There may be some occasions where honey- 
 comb concrete work can be used, i.e., where larger sized broken 
 stone is used and only enough mortar mixed in to coat the various 
 stones over and cause them to adhere whenever they come in con- 
 tact, leaving many interstices between ; but generally solid work is 
 preferable in building these abutments. Instead of filling up the 
 mould at one time, and as quickly as possible, I put it up in 
 successive layers of equal height with the courses of cut stone 
 in the facing, my object in depositing the concrete in layers be- 
 ing that in case the bottom upon which it is laid should settle, 
 
60 RAILWAY MASONRY. 
 
 only such layers as were already in the work would settle with 
 it. Any extensive settling would result in cracking the concrete 
 then in the work. If the entire mass were in position at the 
 time of such settling, a fissure or fissures would be noticeable ex- 
 tending from the bottom to the finish, or nearly so, being of 
 course greater in width at the bottom. This would probably sep- 
 arate the concrete into several distinct parts utterly without 
 bond, thus weakening the work. But some one may remark that 
 the same settling might occur in the other mode, and that it 
 would not be apt to take place until considerable weight of con- 
 crete had been used: all of which is true. But should the set- 
 tling occur when nearly all the layers had been run in, at least 
 the upper portion of the fissures could be filled with thin mor- 
 tar, called grout, and the next layer of concrete would adapt it- 
 self to the depression of the main bulk. Again, in layer work 
 these fissures are not perpendicular, but zig-zag, somewhat sim- 
 ilar tq the same in stone work, the bond being still preserved 
 but lacking cohesion. In heavy work, which depends greatly 
 upon its weight as a power of resistance, nr great injury ensues, 
 but in a light wall depending more upon remaining perpendicu- 
 lar, the impairment of its strength by such cracks often results 
 disastrously. 
 
 No matter how carefully foundations are prepared, something 
 of this kind may occur now and then ; the bottom may not pre- 
 sent a uniform degree of compress.'bility. Especially is this no- 
 ticeable in repair wotk. For instance, old work being torn out 
 and enlarged work put in, the extension, resting upon a new bot- 
 tom, is more liable to settle than is that portion formerly weighted 
 and compressed by the old work. In building with concrete any 
 carpenter would easily understand the mode of putting up stand- 
 ards in which the plank framing can be inserted and from which 
 
RAILWAY MASONRY. 61 
 
 it can be removed. The bed for concrete may be upon timber, 
 or in case of a floor, well rolled gravel is proper, although in any 
 pavement or floor great pains must be taken in preparing the bot- 
 tom, or the work will certainly crack. 
 
 I will not undertake to explain this subject farther. The princi- 
 ples remain the x same, whether a tank, cistern, abutment or ordi- 
 nary wall is to be constructed. 
 
RAILWAY MASONRY. 
 
 CHAPTER IX. 
 
 PROTECTION AGAINST SCOUR. 
 
 The banks and beds of some streams are composed of soils 
 very susceptible to scour by the current. Especially is this the 
 case where the material is loamy earth or sand, these beds being 
 often of such depth that there seems almost no limit to their 
 washing out. Owing to the eddies and whirlpools created by 
 
 PIER PROTECTED BY CRIB WORK. 
 
 such obstructions as piers, the greatest scour can be anticipated 
 directly at and around the base of the pier. The only inexpen- 
 sive method of protection in such a case is to deposit a heavy 
 layer of large boulders all around the pier. In most instances 
 this will suffice, but should the current be very strong, these 
 loose boulders will quite probably be washed down the stream 
 again, leaving the masonry exposed. The only remedy then is to 
 crib up a certain space around the pier with heavy logs and fill it 
 
RAILWAY MASONRY. 63 
 
 with boulders or a very heavy bed of concrete. The latter plan 
 is the most effective of all, but an apron of concrete three or four 
 feet in depth is a very expensive affair, equalling in cost a 
 like superficial area of the bridge above it. Unless absolutely 
 required to clear the channel, piles which have been driven around 
 the site of a pier should never be drawn. It is better by far to 
 allow them to remain and fill up any vacant space with rip-rap, 
 the drawing of a pile leaving a cavity as dangerous as any exea- 
 
 PIER WITH APRON OF HAND LAID RIP-RAP. 
 
 ration. In some cases the pier can be protected from scour by 
 driving piles around it and filling the space with rip-rap. If no 
 large stones are available, a bed of broken stone can be thrown 
 around the work and this paved over with hand-laid rip-rap of 
 stones about eighteen inches or more in depth when placed upon 
 their edges, as per illustration. This manner of laying rip-rap 
 is especially adapted to the banks of a stream. 
 If well under water all this work must be done by men in div- 
 
64 RAILWAY MASONRY. 
 
 ing armor at very high wages and with several attendants to keep 
 the air pumps in operation and to await the signals of the divers. 
 The manufacturers of diving apparatus charge extraordinary 
 prices for very little, the main part of which can be gotten up in 
 any company's shops at very small expense comparatively. 
 
 I hardly think it advisable to give any directions or illustrations 
 concerning the making of diving outfits. I unfortunately got 
 up an experimental suit once upon a time and as a result had to 
 make constant use of it for twelve days, and found it anything 
 but agreeable for an amateur. It is one of those cases where 
 " 'tis folly to be wise," and where the masons can step aside and 
 allow the professional diver full scope for the exercise of his 
 ability. However, should any of my readers feel very much dis- 
 posed to do a little deep water work, I will cheerfully furnish 
 them all necessary information free of charge and wish them all 
 success in their undertaking. 
 
 In concluding these articles on bridge foundations and masonry 
 I will only mention the necessity for carefully judging the proper 
 mode of founding, which must depend upon the nature and depth 
 of the bed of the stream. I have endeavored to outline the prin- 
 cipal methods of providing foundations and protecting them, but 
 in the rush of active work I have found but little time to enter 
 into details as freely as I could wish. Experience is the great 
 teacher, and it will furnish all the minor information which I have 
 overlooked, ar.d aleo much which I have vet to learn. 
 
THIS BOOK IS DUE ON THE LAST DATE 
 STAMPED BELOW 
 
 1914 
 
 6)an'62LU 
 D LD 
 
 DEC 10 1961 
 
 30m-6,'14 
 

 It 3 
 
 UNIVERSITY OF CALIFORNIA LIBRARY