CHAPTER IV.
IRON PILES.
Arrangement—Driving—Sinking by Water-jet.
"Tell me what you have learned about iron pile fixing, same as you have promised me you will about timber piles."
"Very well. Here goes, then; first a word as to iron piles generally.
"Although a group of piles when properly strutted, tied, and braced have plenty of stiffness, if you have to deal with them singly they are never stiff, but they can be made steadier when getting them down by having two large pieces of wood with a half hole in them, something like the shape of the old village stocks, and by putting or lowering it at low water until it is bedded in the ground. It must be weighted though, so as to prevent it floating. It acts like a waling, and is useful when the ground is treacherous, and provided it is level.
"From watching the behaviour of piles when doing repairs and at other times, I think it wants a lot of careful arrangement to be sure the load is acting equally on the whole group, or, as may be intended, on say a few piles, and straight down the centre of each pile, for it makes a lot of difference to the strain on them, and it is not easy to make them all take the load at once as wished. It wants a good deal of attention, and the piles are not unlike a pair of horses that are not matched and don't work together properly—kind of now me, now you business. Before finishing reference to driving and screwing, let me say all the parts should be properly fitted together at the works and numbered so that the putting up on the ground is easier and in order to be certain all the bolt-holes agree; and it is well to have the lengths interchangeable and all the same, except the making-up pieces, and all bolt-holes as well as the flanges should fit in every respect.
"When columns rest on a masonry, brickwork, or concrete base the piles ought to have a ring or base-plate right round them to hold them tightly together. It lessens the pier being shaken, and saves the side pushing of the holding-down bolts. I heard an engineer say the weight of the pier above their ends should be not less than about four times any force that might tend to lift them. The anchor-plates should be well bedded upon a solid mass or the strain upon the pier may go in one direction, and that the one not wanted. Don't be afraid of bracing and strutting piles, the more of it the better. I don't think much of a single turn of a screw blade a few feet below the ground for taking a load, although some good for steadying purposes generally, because the bed may become scoured out below the blade and then the screw is no use. Therefore the depth of possible scour ought to be positively known before relying upon the blade for permanent support. A lot can be said as to the grouping of piles, whether in triangles or in rows. In a triangle, although the load upon the foundations is spread over a larger area, it does not give as much lateral strength as when the piles are placed in one row, and taking everything into consideration I think if I had six piles to put down I should not place one at the top of a triangle, two lower down, and three at the base, but have two parallel rows of three piles; besides it lessens the length of the struts and the bracing, and that is something, but, of course, each case requires to be treated in a special way, and I have noticed when doing repairs that if there are six piles fixed thus, ∴ in a triangle, the wind and other force acts principally upon the bracing between the parallel rows, and the pile at the point does not do much towards keeping the others in the right place; anyhow the bracing there does not seem to hold as tightly as it does between the parallel rows, and I have had to watch groups of them in storms, and when the sea has been high, and that is my opinion."
"Now, as to fixing iron piles."
"When the ends have to be placed in rock, which has sometimes to be done in shore pieces, 'jumping' the holes in more than about 2 feet of water is to be avoided, for if the water is not still the holes become filled with sand and drift, and you must not take the jumper out but keep on continuously making the hole. It is ticklish business, because sometimes the rock grinds the jumper, and then the wings and point wear away. Occasionally they have to be worked inside a cylinder by ropes, rods, and gearing fixed in it, the cylinder being movable and held from the end of the part of the pier that is finished, but where the water is deep the ends must be put in the rock in Portland cement by divers.
"I have driven a good many iron piles with a ram, but you have to be careful, no matter whether the soil is sand, gravel, clay, or silt. I like a copper ring on the head of the iron pile and a good long timber 'dolly,' not less than 4 or 5 feet in length, and then the ram does not burst the top. When the ground is hard the best way is to make a hole by jumpers of about 3 inches less diameter than the pile to be fixed, and in chalk soil it is doubtful whether they will go down right unless that is done; perhaps they won't drive at all, or a lot of them will be broken. I have used a ram weighing from 1 to 1½ ton for an 8 to a 10 inch pile and about a 3-feet fall, and never more than 4 feet, unless you want to deal with some old metal merchant that will give a good price for the scrap, and it does not matter how many get broken, or it is a positive advantage to break a certain quantity out of every lot, so as to have a big price for such difficult driving, and get 'extras' that way."
"I understand, no breakages deducted."
"That's it. I have driven them at the rate of fully 6 inches a minute for a few feet. They often rebound, so I had a boy with a lever, the end of it being clinched to the pile. Directly the ram fell, he gave the pile from quarter to half a turn for the first 4 or 5 feet of driving, and they scarcely rebounded at all; and he earned his wages, for I considered fully one pile extra was got down out of about every ten by the turning movement. The points require to be regulated according to the ground. From 1½ to twice the diameter or width for the length of the point is about right, but if it is made too sharp it may break. Iron piles that have to be driven are seldom more than 12 inches in width, and the thickness of the metal is generally from one-ninth to one-twelfth of the diameter. I heard an engineer say, I think it was Mr. Cubitt, experiments showed that a T-shaped cast-iron pile about 30 feet in length, should have the top of the T two and a quarter times the length of the upright part, and the thickness a twelfth of the top. Of course, the length of the pile must be considered. I doubt if you can get equally sound metal throughout when the thickness is much more than 2½ inches. From ¾ to 1½ inch is best, and piles I have broken up always seemed more even throughout about those thicknesses; but there, I suppose it is all a question of care in casting and proper machinery.
"One thing, don't drive any piles from a floating stage on the sea if you can help it, it will make you pay for the privilege; besides I have known some places where the sea was always so disturbed it could not be done, even if the moorings were as tight as you dare make them. Driven iron piles are not much seen now, and Portland cement concrete seems the fashion, and no doubt it is better. Still, iron piles can be driven in deep water without much trouble from it, and one might combine the two nicely—the iron to act as a shield to the concrete while depositing it, and give it time to set without disturbance and preserve the face."
"Have you sunk any disc piles?"
"Yes, they are all right for fine sand and silt, but you must be careful the discs are the same in form and dimensions upon all sides, or a pile will almost certainly tilt and sink crookedly. I was busy on the Lancashire coast once, and heard that Mr., now Sir James Brunlees, tried a lot of different kinds of hollow disc piles, and that the best was one with a plain flange base three times the diameter of the pile, and circular, with the bottom nearly closed, it only having a hole in it in the centre of the base 3 inches in diameter. Some ribs and cutters were cast on the bottom of the disc to break the ground up if it was hard. This is what I know about disc piles and have been put up to.
"When piles have to be sunk by water pressure, rotate the pile, and don't let it be still long, so as to lessen or prevent surface friction on the pile shaft and the sand settling round it. Always have circular discs and not too large, not above 3 feet in diameter, for they do not sink nearly so easily as the size of the disc is increased. About 2 feet discs are my choice as they go down much quicker than 2 feet 6 inches or 3 feet.
"Don't try to sink them in sand to a greater depth than 18 to 20 feet, and remember that although they may sink easily for about 12 or 15 feet, afterwards they will want some labour. When you have finished sinking piles with the water-jet, it is best to drive them down an inch or two further by a heavy ram and a very small fall, or heavily weight them as soon as possible after having done with the jet; then the disc has a bearing on firm and undisturbed ground, and if you are afraid of a blow on the pile you can have a heavy weight placed on it to help it into position and the sand to become solid. Obtain considerable pressure of water, and always cause the pile to rotate when sinking. Don't let the pressure get much below 40 lbs. per square inch, and use about 60 lbs. if you can get it. I have worked up to 100 lbs. per square inch but not beyond, and fancy there is then too much pressure, and that more sand is disturbed than is necessary. All that is wanted is to make the sand boil and remove itself from the underside of the pile and disc, but always have a few ribs or cutters on the underside of the disc as they loosen the sand as the pile is rotated—besides, should there be a strip of harder soil, it may be impossible to sink the pile without them. A rather large tube and a moderate pressure are best, and a tube not less than about 2 to 4 inches in diameter according to the size of the pile, and it is better from 3 to 6 inches, of course, if the pressure is high a larger size jet can be used, but if it is less than 2 inches it will only make a small hole, and too much below the disc, and not enough water passes through it. Try to ascertain what pressure of water makes the piles sink the easiest. Sometimes they will go down at the start as much as 3 feet in a minute, and often 2 feet, and from that to 1 foot they should do for about the first 6 or 8 feet in sand, but then the rate quickly decreases. The nozzle should be properly shaped so that the jet is whole. I mean the shape of the pipe at the place where it touches the sand. What is wanted is to get just enough force to cause the sand to separate and boil and to push it away from the disc and no further, or some of the water power is wasted, therefore a good volume of water is as necessary as a high pressure. You understand?"
"Yes."
"The tube should project about 6 inches below the bottom of the disc. A toothed tube can be fixed round it so as to help to disturb the ground and strengthen the pipe. The water supply may perhaps be obtained at a sufficient pressure from the local water-works company, then, probably, a force pump will not be required, but the pressure that can always be relied upon should be known.
"In sand, and when the water power can be easily obtained, I prefer disc piles to screw piles, because there is hardly any chance of breaking or injuring the disc; you always know where the disc is, but cannot positively say where the screw is—it may be sound and may not be; in addition, the disc is stronger than a screw blade, as it can be strengthened by ribs almost as much as one likes, and the disc in sinking is hardly strained at all compared with a screw pile. They can be sunk quicker, and do not require nearly as much plant to do it, for when you have a force pump, a guide frame—something like an ordinary pile-driving machine 25 or 30 feet in height, with a grooved pulley at top in which the chain or rope runs so that one end can be attached to the pile flange either by jaws or temporary bolts, and the other to a crab winch, which, with the guide frame, is used for lowering and keeping the pile in position, and stay the top of the guide frame by ropes to short piles driven into the ground—and a hose and two levers, with a collar to grasp the pile so as to rotate it, you have about all thespecialplant that is wanted.
"Of course, piles can be sunk by water pressure from a floating stage such as a barge, pontoon, or raft, so long as the pile is kept vertical, but there are the same objections to that method as with other piles. Piles are, however, got down much quicker and easier by the water jet than by screwing or driving, but the ground must be loose granular soil, such as ordinary sand.
"There is not much 'extra' to be got out of iron piles. You can only dodge a bit with a length short now and then when you have the right parties to work with, and the inspector is cross-eyed or a star-gazer, but you may get something 'extra' out of the filling them in. As usual I draw the line somewhere. Everything on earth has a boundary line. This is where I draw it. Listen!
"After as much water as possible—possible is a nice elastic word—is got out of the pile, and it is as clear of deposit as convenient—another nice easy word—and before commencing the filling, I put inside the pile everything I can get hold of that is dry, for just then I have but one way of looking at anything, and that is to consider it Portland cement concrete, unless it costs me more to use it; but when the filling is concrete, I make that as dry as mixing will allow, and sometimes hardly that. The inside of the pile is sure to be wet, and that will help the mixing. I never ram the concrete, but gently cast it in. It is only a sort of anti-rust covering, and is put in for that and to keep water out, and no weight comes upon it—it is not like the hearting of cylinder bridge piers. Ramming the concrete is not far from being a mistake, because the pile should have a chance of contracting without straining, and may be it will crack; and it is just as well to remember that although by ramming tightly you may get more solid filling and better protect the inside from rust, the pile may be strained, and it is a choice of evils, possible rust, or strain."
CHAPTER V.
TIMBER PILES. PILE-DRIVING.
General Consideration.
"Now, as promised, I will tell you of a little bit of free trade with some timber pilework."
"That's it. I am waiting for it."
"Well, they let me have 400 feet run of pile-driving. Double row of 16 to 12 inch piles, and there were some fine sticks nearly 55 feet long, and that is a long length for a sound pile, and you have to pay for them."
"Before you begin to tell me how you scamped it, give me a hint or two about piling, and say what you have learned from experience."
"All right. First, when a pile is some distance below the bottom waling, which should be fixed as low as possible, a lot must be taken for granted, and it cannot be controlled much. I know this from drawing many piles; hundreds, I may say. After they are down about 5 or 6 feet they begin to do as they like, and take to irregular habits, and you cannot be certain the points are straight unless the ground is the same throughout, and it hardly ever is. In fact, the resistance they meet with varies, and then they accommodate themselves to circumstances; and even when the ground is very soft they turn to the line of least resistance, and if they have to be driven through several feet of soft earth to reach the solid, they may play tricks and bend about in the soft soil in go-as-you-please style, yet seem to be driving nicely; or they may stick between boulders and can't be driven further and appear to be firm as a rock, and so they may be as long as the boulders do not move, but they often do after a time, should the ground become wet, and sometimes when the next pile is being driven.
"Always be careful to see that the shoe has as large a bearing as possible for the end of the pile, and is long in the point, and more pointed as the soil is harder. Take a 12-inch pile with a 4-inch or so seat in the shoe for the stick. Well, 12 by 12 is 144, and 4 by 4 is 16, and therefore the pile end has a bearing area upon the pile shoe of one-ninth of the area of the pile. No wonder the bottom often becomes ragged and the pile shifts. The shoe should have a good hold of the timber, and be put on true to a hair, so that the point is in the exact centre line of the pile, or look out for squalls. Now high falls and light monkeys are out of fashion, and short falls and heavy monkeys are the thing, not so many piles are injured. Pushing them down is better than breaking them to bits. You should have the monkey so that its centre falls upon the centre line of the pile. The average centre of the pile should be marked on as exact as possible, and the end of the pile be cut to a template, so as to make it fit tightly to the shoe, or it may not drive straightly. I always take a lot of trouble that way and seldom have to draw a ragged one, and believe they used to drive straight. I mean from start to finish about the same number of blows and to the same depth and vertically.
"When hand-driving in soft earth—it's slow business at the best—weight the pile when the monkey is being lifted so as to stop the quivering and press it down and keep it from springing. Provided the work was of importance, and I was the Cæsar of it, before any pile was pitched ready for driving it should be inspected, its dimensions taken, it should be numbered, numbers be burnt in, and every foot from top to bottom should be marked on by a brand; and perhaps the numbers should begin at the bottom and work up, as there is not so much chance to tamper with two figures as with one, &c.
"Pile-driving is fickle work, for sometimes the piles stick because the points can't pierce the earth, and at others because they are held by friction on the surface of the piles. I have known the shoe to be cast, and the pile end look like a bass broom, and to be all in shreds. When piles split a great deal and they must be driven, the best thing to do is to get harder wood, lessen the fall and increase the weight of the monkey; same as in tunnel lining, when stock bricks are crushed, blue bricks have to be put in. The nature of the ground should govern the hardness of the wood for piles. I always pick out darkish even-coloured wood, and sniff for the resin, and the more in it the better for me. You don't catch me driving many white wood piles, for they become dry and break off short, and are not the timber for piles. Once a bother arose about some piles. There was a layer of hard gravel, and by the way the piles were driving I knew they would split, so I gave the word that Memel piles were not hard enough for such gravel; and I worked it humble like, and said to the engineer, 'I think you will agree, sir, you can't expect me to be answerable for smashing them until we get into the soft ground again. It wants rock elm or as strong timber for this soil.' After smashing a few to shreds, they supplied us with rock elm piles, and then we managed. It is true to say in the same soil the harder the pile the better it will drive, and therefore with less trouble and expense. The monkey should have an even widened-out base where it touches the pile head, so as to get the weight as near the head of the pile as possible; it also falls straighter than the long thin rams of nearly the same width throughout. Grease the ways well, and take care they are as straight as a die, and exactly vertical if it is upright pile-driving, and you'll save money. Make the blows quickly in fine-grained soil, so that it has not time to settle round the pile. In clay there is no occasion for such quick-driving, but take care to prevent the piles rebounding. Remember the same system does not do for every soil, for quick driving in hard soil sometimes smashes the piles; perhaps the earth has not had time to become displaced nicely and settle before being jammed again, and then the pile point turns and quivers and soon shreds, and cannot be driven down properly. Anyone that says piles make the ground itself firmer when they are driven into it, and so cause it to support a heavier load, will have to prove it before that can be swallowed. It is the friction on the sides of the piles that principally sustains them and not the bearing of the points. In hard soils drive slowly, for it is like chipping up a stone with a hammer. You must do it gently, or it will break the tool; and as you can't clear out the hole in driving piles, it seems to me time is required instead, so that the pressed out soil may settle away and take a bearing. I tricked a chap once pile-driving from a barge."
"How did you do it?"
"Well, it was bound to be driving from a barge or nothing, and there were three pile-drivers for us, almost as many as we could work, as the driving had to be done by degrees. Some of the work was let to a chap I did not like too much, and the rest to me. They gave me the choice of plant, so I said to the engineer, 'May I have two of the pile-drivers upon my barge, as Faggitts'—that was the other chap's name—'only wants one.' I got the two. Now Faggitts knew about driving piles on land, but had never done any driving from a barge, so I had a bit in hand of him. If you take any pile-driving and it has to be done from a barge, have more than one pile-driver on it if you have the chance; but don't place them close together, make one steady the other, and have as many as you can conveniently work at once; because, in my experience, the more you have the less the swaying, and the piles drive more regularly and the barge is steadier, and you don't have so much bother with the moorings. Of course, if the monkey does not fall flat upon the pile head the pile does not receive the full force of the blow in the right direction, the pile may be driven slightly crooked and it does not get properly treated and won't penetrate so easily, and therefore you lose money. Old Faggitts found that out in the soft soil we were driving them into. I said nothing to him, but he did to me. I never told him.
"I have read somewhere that it is wearying work going into details, but when you have to do the work yourself, unless you take care of the details you'll find they will make it hot for you; and after all, any one can speak generally, but when they have to explain in detail what they think they mean, and have to do the work themselves, they will soon find out that unless you know the details and attend to them carefully, that you won't make a profit nor anyone else. Anybody can talk tallish after about a fortnight's training, but then they have to pull up or they will fall at the next fence, which I label 'details wanted.' That's by the way, and I may have made it too strong, but it is as well to sound your engineer. No general is successful unless he knows the strength of his enemy and as much more about him as he can, and acts accordingly, and chooses his own time and place for a battle.
"Driving piles in groups, especially if the ground is soft, and not singly, is good. They go down more regularly and fit tighter, and they seem to drive quicker. I have driven cheap fir piles between elm piles that way, and a good many of the soft ones split when we had to drive them singly. Have as few key piles as possible, because they are liable to be jammed before they are down to the right depth, and then, if it is a cofferdam, it is probable a leak will occur under the key pile, because it is the easiest place for the water to soak through, and the other piles being down below it, stop the flow, and it soon finds out the short-driven key pile. When I notice a spot in a cofferdam at which water leaks through the bottom, unless it is an old stream bed, it occurs to me that the piles have not gone down properly, have got bruised, bent, turned up, or broken off, and I have found out that was the case on drawing them when the cofferdam was of no further use. Once I was ordered to drive some three-cornered piles at the turns in a cofferdam on a river front, but said, 'Square or circular shall be driven, but any other shape I will try to get down properly, provided they are carefully fitted and bevelled, but you really can't expect me to be answerable.' They deducted a fixed amount if after the piles were pitched there were more than a certain number visibly damaged or smashed, so you may depend I had a good look at the sticks before they were driven.
"I have driven piles 60 feet in length, kind of giant sticks, but 45 to 50 feet is long enough for good sound piles. Socket pile driving piecework I avoid, for the joints are ticklish business; and if a pile of ordinary length will not do, I throw out a mild hint whether the better system to use would not be Indian brick or concrete wells, or to spread out the foundations so as to get a sufficiently large bearing, or have a fascine platform, and sink it till it is firm, and test its stability properly by a load.
"There is a great deal in starting the driving correctly. I always am very careful at the start, and experiment and watch how the piles drive, and vary the fall a little until the best is known. Few considerable stretches of ground are of the same kind, and to fix a certain fall throughout is not the thing, it generally wants varying. I have easily driven piles in fine sand by having two small pipes, one each back and front, reaching a few inches below the point of the pile, and sending water down them under pressure, and by keeping the pipes on the move so that they can't be gripped. I worked out with the pipes the place where the pile had to be pitched and made a profit that way, because not only did the piles go down much quicker, and a lot of blows were therefore saved, but the piles were easier to start right. I used to call my two pipes the two bobbies, because they steered straight for their station, and these two did the same office for the piles.
"Now a word as to systems of driving; the method must suit the ground. I knew a man that believed in nothing but driving by gunpowder; he must have been going in strong for gunpowder tea, or have been in the militia, for the soil he had to do with was not homogeneous, and had boulders and other hard obstructions in it. It was not like soft sand and clay, consequently many of the piles were broken. The noise also was a nuisance in the dock, and cattle that had to be unshipped from the steamers were so unruly that they had to stop the gunpowder pile-drivers; besides, to do much good with them, a large charge is required, or it costs too much. The power necessary to work the machines is better obtained by other means, and can be without so much noise or shock.
"I have used all sorts and sizes of monkeys, from half a hundredweight to four tons, but heavy rams and short falls are the best, and steam for the power if the contract is considerable and will pay for such plant; otherwise hand, unless the piles are large and have to be driven a long way. A sixteen hundredweight monkey is about heavy enough to work nicely by hand, but it is not sufficiently heavy for a 12-inch pile, except in soft ground. For sheet piles a hand machine is good enough, for it can be moved easily, and six to eight tons weight, being about that of a steam pile-driver, costs something to shift, unless there are rails and tackle handy. Of course the blows are quicker with a steam pile-driver, and in sand that is a great point as the ground has no time to settle round a pile; but should the soil vary and be hard and soft, it is well to slow down the machine at first to lessen the fear of smashing the piles and shaking them till they tremble to destruction. I have worked a lot of different kinds of plant, and driven many piles at once, and the power was obtained from one engine giving the motion by driving bands, and in another case with drums fixed on the engine shafts, the chains being carried over sheaves to the different pile engines.
"This is my idea of pile-driving:—
"1. Steam driving. 2. Hand driving, if the piles must be driven very slowly, and there are not many to drive. 3. Never use gunpowder pile-drivers, always prefer steam, hydraulic, atmospheric, or some other motive power.
"Gunpowder is more for blowing up than anything else, in my opinion, and I know the pile shoes often shed in driving with it; that is, they loose their hold of the piles and become detached.
"A pile should penetrate regularly, and after the first few blows drive less and less, as then you have a good idea it is all right and uninjured. Uneven penetration is a proof that piles are not all right, and when they sink suddenly there is almost sure to be something wrong, and they are most likely being over-driven, shredded, frayed, shoe-cast, or split up. The rate of descent should be noted. It may be considered they are driving properly if they sink about a foot at a blow for the first one or more, and then 8 or 6 inches, and when they get down to one-eighth, one-fourth, or half-an-inch a blow for some successive blows it is time to stop and consider. I have driven piles with as few as ten blows in sand with the aid of two water pipes at work fore and aft, as mentioned before, and have had to give a pile as many as 300 blows, and when they want as many as that, with all due deference to everyone, the ground is firm enough to build upon for permanent foundations without piles. My experience goes to show that piles are often driven further than they need be, if only for use as a cofferdam, and that back struts and counterforts are better than extra depth in the ground, provided leakage is prevented. 8 to 10 feet down for solid clay, 10 to 12 feet in gravel, and about 15 feet for ordinary soils, and more care taken to ascertain the piles are where they should be, and that they are sound and whole, and not turned aside, bulged, and injured, would be my practice. In boulder ground, in my opinion, piles should not be adopted; for broken, crushed, and twisted fibre bass-broom shreds are not piles; they are out of place and should be used for clearing leaves from garden walks. The longer the piles the softer should be the ground they have to be driven into, or they shake so much, and cost more to drive.
"Unless always well buried and at such a depth that neither the moistness nor condition of the earth vary, I scarcely believe in timber pile foundations at all, except in very peculiar cases, and as a kind of aid to the main support or to help to prevent the toe of a wall from being thrust forward, but for cofferdams, jetties, piers, and such structures, of course they are useful. In hard and most gravelly soil avoid them, and also in sharp sand, if you cannot use the previously-mentioned water-pipe arrangement fore and aft; and although in ordinary clays they drive nicely, and you make a bigger profit than in sand, it puzzles me to discern what is the use of them for permanent foundations, except to help to prevent a wall sliding forward, because when a pile is driven into most clays the clay becomes tempered and softer, and a layer of concrete put in a proper distance down is better and much more certain, and distributes the load more equally. Elastic soil is bad in which to drive piles, for it yields and then rebounds. A pile will sometimes spring back almost as much as it is driven, and in such a case it is well to let the ram or monkey rest on the pile immediately after the blow is given, if you are hand-driving, or have an arrangement so that it is weighted directly each blow is delivered, and perhaps the best way is to hang heavy weights on the pile. In driving in firm sand the ground at the surface becomes considerably displaced, in clay about half as much as in sand.
"Pile-driving is different to masonry, and I always read the specification for pile work, and then judge whether and how a bit 'extra' is to be obtained, and guess as to the knowledge of those I have to deal with, and act accordingly. Sometimes a specification simply says all the piles are to be driven to the same depth or as shown on the drawings. That may be right should the ground have been tested by experimental driving, or the nature of it be known; but if not, I don't take much notice of the specification, because I hate waste, and can't afford the luxury; and it stands to reason that simply because a lot of piles are driven to the same depth they are not equally firm, nor will they support the same load unless the soil is exactly the same, and they drive well and regularly to the same depth and all nearly alike inches by inches, and this seldom occurs. Often 'extra' profit is to be had, as you will soon hear described, for when piles will not drive further than half or a quarter of an inch a blow they satisfy me they are tight enough for the purpose intended if they are at a fair depth and not wedged by boulders; but between ourselves, should a building of any kind have to be erected on piles, and anyone I really cared about had to live in it, I should always weight the piles for as long a time as possible after finishing the driving and reasonably more than the permanent load, watch the effects, and act accordingly, particularly in elastic soil.
"Remember a pile sinks less after it has rested than if it be driven continuously, therefore always take note of the set when the driving is proceeding, and not just at the start, or after an interval, although one does that for one's own benefit, and with a view to 'extras'; and no one wants to drive a pile an inch more than can be helped—at least I don't, nor have I, and it is certain never shall.
"You want to know when to stop driving. The time has arrived when a pile penetrates very little, and nearly equal for several successive blows of the heaviest ram by which it has been driven at the usual fall.
"A word as to tie and sheet piles before referring to the way I have worked piles for 'extra' profit. It is difficult to make a main pile and a tie act together, one or the other is nearly sure to have to bear more than its proper strain, and the tie rod becomes eaten by rust, bent, and loose in the piles. In taking down old banks and quays you will generally find the main pile and the tie pile are not held tightly by the tie rod, the tie pile is loose or pulled over, perhaps when first strained, and then becomes disengaged when the main pile has set to the strain. The tie rods want to be very carefully and frequently adjusted, if possible, and big washers and cleats on them are required. They hold best in firm sand, not so well in clay, and in large light loose soil, such as ashes, they are not much good. It is an impotent arrangement and it is always uncertain whether they will act together. Don't undertake to tighten up the rods. Fix the piles, and let the engineer see to the tightening up, as you may injure the piles.
"When I have to drive a lot of sheet piles, of course the piles are supplied to me, and I only take the driving. You may be sure the timber is right, and that the edges are sawn square so as to drive tightly together, and that the point is in order. I find it always pays well to temporarily place a baulk at the ground line like a waling, but not fixed to the sheet piling, as it guides the piles, lessens the shaking, and they drive easier and better. It appears to me piles cannot vibrate without force, and that is not where it is wanted, so it is wasted motion. Agitation when drawing piles is all right, but when you are driving you want it in the ground itself, and not in the piles. Once when I had to drive some thin sheet piles, I made a movable guide frame, the side against the sheet piling being planed and greased. It was like one bay of a timber-lattice bridge, and it well paid for itself as it steadied the piles.
"In taking a contract for drawing piles always find out how long the piles have been driven, for if they have been down many years they will be much harder to draw than if they have only been fixed a few months. They can be drawn by lever, hydraulic jack, and chains, and pontoons in a tide way."
CHAPTER VI.
TIMBER PILES.
Manipulation for "Extra" Profit.
"Now, I'll tell you about a bit of 'extra' dodging that rather scared me. First, let me say, no one can ever know how much I hate waste—it can't be measured."
"You and me are alike, a couple of turtle doves on that question."
"We are. Finish up, and we will have another. I remember Lord Palmerston said, dirt was matter out of place, or something like that. Now I think piles are often good timber out of place, so I followed that lesson and said to myself 'What a lot of good timber is going to be buried; and really it is breaking and loosening the ground too much to please me, and that's a mistake, besides placing extra weight on it'; so after dwelling on the subject as much as suited me, I decided it was waste, and that it was poison to me. I had trouble on my mind about it and it made me feel thirsty and does now. Pour another out."
"There you are."
"I'm better now. Well, I wrestled over the waste question some time, and finally made up my mind not to be a party to it, it being against my principles, and, like us all, no man shall make me swerve from them, especially when they agree with my pocket."
"Certainly; shake hands. That is good!"
"Well, there was only one way to do it, so in order that every one might have their way to a certain extent I decided to drive first one pile to the depth as ordered and one to the depth that suited me, and therefore both parties were satisfied and believed they had got what they wanted; for while I left the other man, that is the engineer—excuse the disrespect—to his happy thoughts, I descended to simple practice in a way very comforting to me. Knowing it is not every pile which is driven that drives whole, or is according to drawing, many often being twisted and knocked to shreds—although I have seen them driven through a layer of old brickwork, and whole, too—and that there is a lot of uncertainty about them in some ground, I dwelt on the matter, and came to the conclusion that according to the drawings every other pile would be driven about 3 to 4 feet too far down, and that all concerned hardly agreed upon the depth to which all of them should be driven, and that I was the chief one to be considered; so I cut off a few feet of the top of nearly every other pile, and varied the length according to whether the pile happened to drive hardly or went down gently."
"Precisely."
"Somehow or other the ground seemed really grateful to me, for more of the piles were cut off than I originally intended. They must have passed the tip—may be the worms did it; anyhow the ground, after a few had been driven, seemed to become harder, and we had more sawing to do than ever. I like sawing. You see your work, and all is above board and nothing hidden and no deception. Suits our principles. Now, you are like me, you don't wish to disturb other people's minds, we are built on the lines of love too much, and tenderness is better than anger any day."
"That's it. I consider you were doing a kindness all round, or as near to it as makes no difference!"
"Well, in order not to disturb any one, it took some thinking over as to the best time to ease off the tops. I mean cut the heads off and put the rings on again, and give the tops a properly seasoned appearance. I used to call it put their hair right. Now, you know docks are not like railway works, for the men are nearly all at one place; here we were in the middle of a large town, but you'll excuse my naming the place, I am too polite to do such a thing without permission. No one was about at dinner time, for all the chaps passed the gates. The place where my work was was shut in nicely, and as there was always a row going on from the traffic close by on road and river, and loading and unloading, it was a really nice little home in which to do a bit of engineering-up-to-date."
"I understand; a convenient spot for scientific experiments in saving labour and the waste of good material."
"That's the lesson. I found dinner time was the best after a week's scouting, and that the road was clear as daylight, for all the spies were away, and there was only one that ever hung about, and he was a young engineer just come to the docks straight from Westminster. He was a nice sort of chap, and a smart one, and had the kind of face a girl looks fond upon from what I have noticed of their tricks. Of course, he did not know much of actual work, being a new pupil, I heard. By the way, what a lot of pupils to be sure some engineers turn out. I almost fancy a few of them must make as much from the schooling branch of the profession as they do from work; but let them, it is nothing to do with me, but this pupil I can say was no fool, though, the same as all new hands, the work was a novelty to him, like a new toy to a child.
"Now, the only thing to interfere with the 'extra' business as described was this pupil, so I decided to fix his attention, if I could, in another direction, and sweetly, so thought it out, and said to myself, 'You have had more difficult things to steer through than this—rather hotter, I fancy.'
"It so happened, just then, they had pulled down an old tavern, and built on the site a showy crib with balcony overlooking the river, and they had a lot of relics on view, and two nicish girls were there. Good figures, you know, and fairly on; so I made myself particularly gracious to Mr. Pupil and pointed out, submissive to his superior knowledge like, a few things on the work. Then the plot was let loose this way. I started a kind expression on my face, and said—
"'I'm afraid you find it rather rough, sir, here; there are not the nice feeding places they have in town, in fact, I think there is only one near here, sir, at all fit for you.'"
"'Where is that?'
"'It is the Anchor and Hope Hotel, sir. I can hardly direct you to it; but you have plenty of time to go there and get back fully a quarter of an hour before the men's dinner time is over, if you will allow me to show you the place, and they have almost a museum of relics of the river.'
"The relics settled it, and he took on all right, and I knew then things were working smoothly and the wind was getting round to a nice steady breeze from the proper quarter. He was a good-natured chap, and one could see liked inspecting the woman portion of creation better than works, at least, during dinner-time, and I don't blame him; some men are built that way, and can hardly say 'no' to a woman, for if they do they think they have done wrong and been unkind. Poor things! Well, we got to the place, and, fortunately, no one was in the private bar."
"You mean lobby. Don't insult the place."
"I humbly beg pardon.
"In we went, and it was lucky, for the better of the two girls was on parade; they were nieces of the landlord, so had more latitude than paid slaves. I went in first, and Mr. Pupil turned to me and said, 'I will be with you in a minute.' Now, that was just what I wanted, a word or two of priming for Polly. So after shaking hands with her, said:—
"'Polly, in a second or two a young swell will be here just new on the works, and will be on the job to the finish, three years, so make yourself pleasant as possible. Three years' presents and fun, to say nothing of odd trips out, are not to be snuffed at; and he is rich they tell me, and should be real good business all round, if you work him right.'
"She laughed; and before I could say any more the door was on the move, and in Mr. Pupil came. I kept my weather eye on him, for I can generally tell, when they run young, whether a chap is smitten sufficient. I saw the place would be a pleasant diversion, just seeing one of the tender gender occasionally, after being all day among men; so to make it appear I was a wolf on business, said, 'Please excuse me, sir, but I have to meet a gentleman at half-past twelve.'
"'Certainly. Do not let me detain you.'
"I just turned to Polly, and said, 'Show this gentleman your museum of relics, and the private room looking across the river, as I think it may perhaps suit him for an odd lunch now and then.' Polly twigged.
"I saw they were started on the road of mutual admiration, and travelling pretty, and that he meant calling again. She also seemed to like the prospect, and knew how to work the game of fascination right, and she did; so the only one in the way of preventing my doing a bit of engineering-up-to-date with the pile-driving was now removed in a nice harmonious way, and to the entire satisfaction of the company's resident engineer—no, hardly that, I mean mine. I consider I did a kind action to all parties, not excepting myself. What a blessing women are, if you use them right. Mr. Pupil had his lunch at the place every day, and Polly and he understood each other, and got on A 1, so I was told. It is soothing work bringing happiness to two young hearts as beat soft.
"Next day we started cutting off the pile-heads, while Polly and Mr. Pupil were occasionally very likely pitching their heads together so that I should not have all the fun. Well, we managed to so drive the piles after a day or two as to be able to cut off, generally during dinner time, from 2 to 4 feet, and I should think must have done over 200, when one day, just as we had nearly sawn one through, up turned Mr. Pupil. Polly and her sister were visiting, and never told me they were going, so the Anchor and Hope did not weigh-in much from him that day. My ganger, who was doing the sawing trick with me, looked a bit down, but he is not so educated as me; so I turned to Mr. Pupil and said—as he asked me what I was doing, and what was the matter—'Got the pile down wrong, sir, and shall have to lift it. I think it's broken off, or gone ragged, may be it has struck an old anchor.'
"He just looked very hard at me, nodded, and went away. It was a close shave, and lucky it was not the chief engineer. However, we had a quarter of an hour to work on that pile before the men came back, and we soon ruined it with bars and tackle. Anyhow, we raised it in no time, for we had the best tackle and everything you could wish for. We split the pile right across. It was only down 5 feet, and most of it in mud. We quickly cut it up into cleats; and out of misfortunes, between you and me, I always make as much as I can. So when Mr. Pupil returned I said to him, 'It wants a lot of experience to know when piles are not driving right, but 25 years has not been lost on me, sir, and I will have good work or none.' Perhaps 'none' would have been the correct word; but anyhow I used it coupled, and you can't complain, for if the pile had been cut there would have been none in the place where it was thought there was. We saved a lot of driving, and I said to myself, 'It is lucky this bit of wharf wall is left to me pretty well, because, as nearly most of the piles are a bit short, the wall may settle if they load it much or build on it; still I think it will settle equally, and then it won't matter so much, and they are not going to build on or near it, that I know,' so I saved nearly 1000 feet of driving on the lot; but here comes the shake. I forgot to say the piles were driven, and a platform fixed on the top for the wall in the old style, but it has gone out now, since Portland cement concrete came into fashion. One day the engineer walked over the work with two or three directors, and, after a lot of talk, they decided to build some 3-floor warehouses upon the quay, after some figuring and dwelling on it. That made me think. I heard someone say, 'The piles are 15 feet in the solid ground, and therefore will safely bear the load.' So they would if they had been, but not many hundreds of them were, and many were in 5 feet of little better than mud, and as some had been cut off 4 feet, those piles were only 6 feet in the solid ground. Understand, this wharf piling was only the beginning of a long two or three years profit for me, and I knew the warehouses would be sure to settle, and if they did unequally, over would go the show. I always avoided the quay wall afterwards; it seemed like a sort of spectre to me.
"One day the engineer sent for me to come to the office. Of course I was there sharp. He said:—
"'I want you to tell me your idea of the character of the ground upon which the western quay wall is erected?'
"Don't you think I was lucky, old pal? Here was my deliverance. It was not exactly a path of roses—there are not many knocking about now—because if I said it was soft ground he could reply, 'You had a very high price for such driving.' If I said it was firm, I felt sure, should they build a warehouse on it such as I heard them talk about, it would sink or topple over, so I had to be careful how the ship was sailed. I answered the engineer like this: 'If you'll excuse me talking to you freely, sir, I will speak my mind; but I most feel abashed with such as you, for you know a thousand times better than me.' He then said to me:—
"'Be at your ease. I wish to hear exactly what you would do in the matter if you were in my position. I have made up my mind; in fact, I have already committed my views to writing.'
"'Thank you, sir. Well, sir, I think it is a risky place, although the piles were many of them dreadfully hard to drive, and wanted a lot of care and all had it, I think, judging from the variation in the depth to which they went down under the same number of blows, that the ground is a bit mixed, and therefore I should choose another site, as there is plenty of room.'
"'Your opinion somewhat coincides with mine. Your idea, I may say, is one which the configuration of the ground leads me to think is the case without doubt. It is therefore probable that in a few days I may have a considerable length of the quay loaded with rails, nearly 2000 tons will arrive for the main and branch lines before the end of the week, as I intend to load part of the quay with about 8 tons per square foot in order to test it. In any case, much as I am urged to commence the warehouses at once, I shall not do so until the quay has withstood the test during at least a month.'
"'That is a heavy test, sir.'
"'You can go now!' He bowed, and smiled his thanks, and I withdrew. Of course, I said nothing to anyone. It don't do to annoy the guv'nor. Well, in a few days the rails came, about 2500 tons of them. The engineer sent for me again and said, 'I wish you to see the rails stacked on part of the quay in accordance with instructions you will receive.'
"I could only say, 'Very well, sir,' and withdraw. I felt I was had again, and went straight away and had a pull of rum. There was no help for it now. I was in the fix and had to get out of it somehow, and what made it doubly worse was being ordered to superintend my own ruin. Listen, for you will when I tell you I might have been tried for having killed or injured 400 men and one director! It was a near squeak for the lot, and as it was—No! I'll tell you in a few minutes what happened.
"Well, we stacked the rails over the place according to the engineer's directions, after Mr. Pupil had taken the levels—he also took them every day, to see how things were going. I made no remarks, for fear I might say something that would lead to further enquiries, and took the cue from a chap I once knew, the biggest rogue out he was; he could please them pretty, and never had any fixed opinions about anything, like some of our politicians, or could twist them about to suit the times; and he set his sails according to circumstances, so as to be pleasant to everyone, and was liked and respected by a lot that knew no better and could not see through him, but he had not a bit of honesty in him. Fact was, knowing I had got all I could out of short driving and cutting off these piles, I played a mild game of respectful bluff, more particularly as Mr. Pupil told me the ground had only gone down a mere decimal of an inch.
"One day the engineer walked over by himself and said to me, 'Come to the quay wall.'
"We got there, and I felt I had soft sawder enough in me for anything. He led off by saying, 'Although this is a severe test it is not altogether satisfactory to me. The rails shall remain in their present position for at least another month. I have known, as in cylinder sinking, subsidence to occur very suddenly and unexpectedly. I do not like the system of foundations upon piles, but have been overruled here.'
"Now what he said pleased me much, because I thought to myself if the wall does break up it will not be exactly a heart-breaking trial to him. Well, all went on as usual for a fortnight, and I heard nothing further till one Friday about 5 o'clock. It was near low water, and Mr. Pupil came to me and said the engineer wanted to see me. I went towards the office, but on the way met him and the engineer and three or four other swells, two of them that came before. I touched my hat, and walked behind. I heard the engineer say, 'Mr. Selectus, although the position is very good, I am not satisfied with regard to the foundations, more especially as I believe the ground to be varied in character; and on an old plan, dated 1720, I note a stream marked here; in fact, Mr. Pupil has searched and found a water-course existed almost from the earliest known times.'
"If he did not say exactly that, it was just like it, anyhow he spoke up pretty straight. One of the directors (I heard they were all such afterwards) said, addressing the engineer, 'I have an idea. The men will cease work, I think, very soon?' 'They will,' said the engineer. 'Have you any objection to their marching and marking time, as it were, upon the rails, as a final test, as I remember we so tested a suspension bridge I had erected at my place?'
"The engineer assented, and remarked that although the weight of 500 men was not much compared to the weight of the rails, the vibration they would create might cause a sudden subsidence. However, he slightly bowed to the director, and said, 'I leave the experiment entirely to you, although I may say it is not unattended with risk; for the test load now imposed is a very severe one for such unstable soil, and the effects of vibratory motion are usually most deleterious.'
"However, the director, after some talking, had his way, so the men were fetched. We had about 700 at work then, the company's own men. I will cut it short. Well, the director told the foreman, as the engineer asked him to do so, what he wished to be done, and the men marched up and down I should think six or seven times. It did not take long, and they soon got into step, for we had a lot of militia chaps at work; and then the director, who seemed to be enjoying himself, said, 'Now we will try three trips, double quick,' so the men went by once all on the smile, and we were as near laughing as smiling allows, when!——
"It chokes me to think of it. Fill up the glass, so that I may keep my pipes open. Thank you, I was near being blocked up. Well, about half of the men were behind the rails, and we were all, except the director-in-command I'll call him, looking on and stationed on a mound close by. I shouted out—seemed a sort of sudden impulse—
"'Look out! the ground is settling. Run for your lives.' About half of the men heard me, and got away, but the front lot went on. I should think 200 of them. Bless you, the ground began to yaw and sink with the rails very quickly, and the wall pressed forward and toppled over in one place for about a 30-feet length with men upon the top of it, and the director as well, and fell very slowly, and quite majestically, right into the river, and there was a splash and crash. I said before it was nearly low water, and I should think there was about 5 feet on the sill and 2 feet of mud. After all, somehow or other, only about thirty men and the director were cast, and they were all taken out right, for there was plenty of assistance. Still one man had his arm broken, which was a good thing for him as it turned out, for the director made him one of his lodge-keepers; but as he was a smart-looking chap, and had been brought up right, and could not work much after, it was an even bargain."
"How about the director?"
"Ah! that's the only fun we had; for I tell you, when I saw the men and the wall go over it made me take root, and my boots were nearly pressed into the ground, and they said I went awfully white in the face. It did give me a shock; but it was lucky the break-up was so slow, for those that could not get off had time to jump and get clear of the rails, but I tell you it was a shave. As it turned out, the director had the worst ducking of the lot that fell in. He went sprawling into the mud; but he could swim, and when we saw him I nearly burst out laughing, only my feelings had been so shaken, for he was smothered in slime from head to foot, and looked like a real savage. All his hair, face, and beard were thick with mud, to say nothing of his tailoring; and I tell you he put me in mind of a baboon just then, and I don't think he will attempt any more testing.
"Of course, the warehouses were not erected upon the quay, and the engineer was not sorry at the way things had turned out. Anyhow, he let me do the clearing away the rails and the rebuilding; and I drove in the piles just the same length as the others, and nothing was said to me or suspected. It worked all right; but suppose a lot of the men had been killed, and the director as well! I tell you it was a near shave, and all before my eyes. It would just have killed me; for I should have known about another 3 feet down of those piles would have made them stand all serene. As it was, my wife said I was that disturbed in my sleep, and kicked so, that she hardly got a wink of rest, and had to double herself up in bed for fear of having her legs broken; however, it wore off in time, although once I sent myself and my old woman clean off the bedstead, and I saw by the light of the moon we were sitting on the floor, and the clothes were all of a heap close by. It made a nice picture of domestic bliss. My wife gave it me hot, and she said she would stand it no longer. I said, 'Don't grumble, you have not got to stand. You are sitting down now, and you ought to know it.' She said she heard me mumble several times in my sleep 'Cut 3 feet off her, Bill!' That was my ganger's name, and, of course, my brain was alluding to cutting off the piles; she thought it was her—no fear. Still, she always makes out I was not so good as I once was, and she felt sure Old Nick and me had night conversations. I laugh over the whole thing now. I hardly did then."