COST OF STEEL STRUCTURES In bidding on a structure, the bid may be for a lump sum to complete the work, or for so much per ton, or for so much per pound. In any case, the contractor will not directly estimate it that way himself. He will take into account and figure on the ten or twelve costs which go to make up the total, and will then transform them into the lump sum bid or the unit-price. These various operations, together with their costs, are given in the following articles.
66. Raw Material and Mill Work. The raw material means the various shapes just as they come from rolls. These vary in price in different years, and at different periods of the year. They also vary in price according to the size and kind of shape. Since the variation in price is due chiefly to the variation in the price of ore and cast iron or billets, there is a certain price for various shapes called the base price; and to this must be added the so-called card extras for a particular shape, in order to get the price per pound for that particular shape.
The base price will be found in standard trade papers covering the steel structural field. The card extras are issued at certain intervals by the manufacturers, and can be had for the asking. Any dealer in hardware can get you one. Sometimes one-half the card extras are to be added to the base price. For example, suppose the base price was cents per pound, and the card extra for 24-inch I-beams was 0.10 cent. The price for 24-inch I-beams would be cents per pound.
In cutting material in the mills, a variation is allowed. That is, if you order a plate 18 feet inches long, it may come to you 18 feet inches long, or 18 feet inches long. So, in ordering material, it is ordered longer than the finished length, in order that it will be correct if the mills happen to cut it % inch shorter or longer than ordered. Of course, if it is longer than the ordered length, it can be cut again after it reaches the shops.
No shop work will be done on angles and plates at the mills, but they will do a certain amount on I-beams and channels. The work they will do on I-beams and channels is punch ing the same or different-sized holes in various parts, cutting and bending, and painting and fit ting connection angles on the ends. It is often cheaper to have the mills do such work as the above, and then have the material shipped directly to the site where the structure is to be located, thus saving some freight and all handling at the shops.
The mills issue cards stating the cost for per forming the different operations as given above. This cost is in cents per pound of beam worked upon. It costs just as much to have one hole punched in the web of a 20-inch 65-pound I-beam 30 feet long, as it would to have 1,000 holes punched. A beam such as the above weighs 65 X 30=1,950 pounds; and it costs 15 cents per hundred pounds, or 19.5 X 15=$2.93, to punch
as many holes as are wanted in the web of that beam. The card showing these extras and their cost may be had by addressing any rolling mill company. The cost varies from 15 cents to $1.55 per hundred pounds, according to the amount of work done.
67. Drafting and Shop Costs. The draft ing cost on I-beams and channel work does not exceed 50 cents per ton when a good draftsman is employed on it. For a general average, $1.00 a ton is about right. Building-truss and plate girder work should not run higher than $2.00 to $3.00 per ton, although some runs as high as $8.00 a ton. As a general rule, the lighter the work and the more difficult, the higher the cost. Some work on a dome where the heaviest angles were 3 inches by 3 inches by inch, and where much curved work was necessary, runs up as high as $15.00 a ton. .
The Shop Cost. The cost of cutting, punch ing, assembling, and riveting, runs about as follows: Column work $14.00 to $20.00 Truss and Girders $12.00 to $25.00 Other Costs. Painting will cost about from $1.50 to $3.00 per ton for two coats. Bolts and spikes are to be counted up, and estimated at the current market prices. Freight varies with the distance of the structure from the shop. Erec tion expenses are variable, depending upon the class of work, and must be figured separately for each case.
Traveling and bidding expenses vary with the distance of the agent from the place where the letting of the contract is done, when he is notified from the home office; and also with the character of the town in which the contract is let. Two days' hotel expenses is a fair amount for the estimate. Haulage may be estimated at 25 cents per ton-mile—that is, per ton hauled one mile.
68. Profit. This varies with the competi tion, and with the amount of work on hand in the shop. If work is plentiful, and men who wish employment are plentiful, the profit can be made low. If the shop is /Turning full, and men are scarce, the profit can be made large, as it does not matter much if the contract is lost; and if it is awarded, then some of the other work may be delayed and the contract worked on.
On the other hand, if work is scarce, and the men are almost out of work in the shop, but prospects look brighter, it would be policy to take the work at a very small profit, or at none at all, or even at a small loss, in order to keep from laying off good men who might leave for other places and thus seriously inconvenience the output of the plant when work "picks up." Ordinarily 15 per cent may be added for profit. If conditions are favorable during the contract, more than this may be realized. If adverse conditions occur, even this profit may vanish. The same estimator should confine his estimates to as few classes of work as possible, and success will be more certain.