franklin institute library PHILADELPHIA Class..B..G24-3j?ook.. + .M82^ Accession... §.03.3... REFERENCE •’igned by at bn shall a book be kept o bed for if. the (A—_£ i ’ one time, without a.... more than two° wl:K e K^ b b7if C ,ro”e 1ms ““rTf a . D °°* *> * I r ^tepi°4 n r'enfe I ; 0U i d ^ liav ' u '«pS’wd°foJ‘ detention of a book beyond*the1?mitai? l t.W EK sh , a !l be exacted for pay for the injury, or wj3aceft!M, Mt il roed , 1 "j" re,! ’ ‘He borrower s direct; and if one 0 r S , b °°, k > ns ‘He Library Committee , ‘ffias <* >«. A,3;.;”Sri:?' »* «~aitSfeKJS ,u c “““ R Irt S Boom - entitled to the pnvileges of the Library THE NEW OMAHA BRIDGE. A REPORT To CHARLES FRANCIS ADAMS, President of the Union Pacific Railway BY George S. Morison, Chief Engineer of the Omaha Bridge. SUBJECTS. I. Preliminary Narrative.3 II. General Description .4 III. Substructure . 5 IV. Superstructure . 9 V. Approaches . 11 VI. Cost.n APPENDICES. A. List of Engineers, Employees, and Contractors ... 13 B. Specifications for Masonry.14 C. Record of Sinking Caissons.15 D. Time, Cost, etc., of Foundations.20 E. Specifications for Superstructure.25 F. Tests of Full-sized Steel Eye-bars.27 G. Letter to Mr. T. J. Potter.28 PLATES. 1. General Elevations and Plan. 14- 2. Pier A. 15. 3. Pier B. 16. 4. Pier C. 17. 5. Pier D. iS. 6. Pier E. 19. 7. Details of Caissons. 20. 8. Arrangement of Air-Locks, Shafts, and Pipes. 21. 9. Position of Caissons on Bed-Rock. 22. 10. Diagram showing Rate of Progress in Sinking Caissons. 23. 11. West Abutment. 24. 12. Approach Piers. 25. 13. Position of Castings on Piers. 26. Company, Record of Water Stage. General Elevation and Plan, Through Span. Through Span; Panel Point O. Through Span; Panel Points I. and II. Through Span; Panel Points III. and IV. Through Span; Panel Point V. and Cross-Section. Deck Span; Elevation and Plan. Deck Span; Panel Points O, I., and II. Deck Span; Cross-Section, Supporting Bent. Strain Sheets. Harness Used to Carry Combination Trusses. Travelers Used for Erection and Removal. Map of River and Proposed Rectification. 18 89 . Charles Francis Adams, Esq., President Union Pacific Railway Company. New York, November i, 1888. Dear Sir: — I submit the following final report in relation to the reconstruction of the bridge across the Missouri River at Omaha. Yours truly, GEO. S. MORISON, Chief Engineer Omaha Bridge THE NEW OMAHA BRIDGE. 3 THE NEW OMAHA BRIDGE. I. PRELIMINARY NARRATIVE. The original Omaha Bridge was begun in 1869, and opened for traffic in 1872. It was built under the directions of Mr. Theophilus E. Sickels, Chief Engineer. The contract for the entire work was originally let to Mr. L. B. Boomer, of Chicago, but by a subsequent arrangement the foundation work was done under the immediate charge of the Chief Engineer. As originally built this bridge consisted of eleven spans, of 250 feet each; the approach on the east side being a solid embankment, and that on the west side a cottonwood trestle which was shortly afterwards filled. In 1877 the two easterly spans were blown down; and the eastern span was never restored, its place being supplied by an inexpen¬ sive timber trestle. The substructure consisted of eleven iron piers and one stone pier, all of which were founded on rock, the iron piers being numbered from west to east. The eastern iron pier and the stone pier at the west end were buried in the embankments of the approaches. Each pier consisted of two cylinders 8-|- feet in diameter, placed 18J feet between centers, and braced together by cast-iron struts and diagonal ties above low water. The cylinders of Pier XI. (buried in the bank) were of cast iron for the whole height of the pier. The cylinders of the other piers were of cast iron below high water, the sections being 10 feet long, cast in a single piece and bolted together through internal flanges. Above high water the cylinders were of wrought iron, Jg of an inch thick, with heavy cast-iron caps. The lower 12 feet of the cylinders were filled with concrete, which appears to have been tight enough to exclude the water; above this the cylinders were filled with rubble masonry. The cylinders were more or less irregular in position; and in providing for the erection of the superstructure of the new bridge it became necessary to figure very closely to overcome these irregularities. The original superstructure was for a single track, of the Post pattern, the trusses being 28 feet deep, divided into twenty-two panels, the web being of the triple-intersection system. The trusses were spaced i8| feet between centers. The top chords were of cast iron, and all other principal members of wrought iron. The new span which replaced one of the spans blown down in 1877 was of wrought iron throughout, of the same depth and width as the other spans, but of the double-system Whipple type, with vertical end posts. The bridge was the most prominent example in America of the Post superstructure and pneumatic cylinder piers. At the time this bridge was built the regimen of the river in front of Omaha was very uncertain, the tendency being for the channel to move eastward rather than westward. Subsequently a cut-off above the city gave the river a more stable character, and the channel moved to the west. Had the construction of the bridge been deferred ten years the channel would have skirted the bluff on which Omaha is built, the entire' bottom-land now occupied by railroad yards and other interests in front of the city would probably have been washed away, and the situation would have become an exceptionally favorable one for the construction of a bridge. In May, 1885, at your request I visited Omaha and made a careful examination of the old Omaha Bridge. As the result of this examina¬ tion, on May 23 I made a full report to you, in which I considered certain modifications which it seemed important should be made at all events, and recommended a plan for the reconstruction of the entire bridge as a first-class double-track railroad bridge with independent roadways for travel. On the 10th of September, 1S85, you telegraphed me to take measures for rebuilding the bridge on the plan recommended in my report. On September 18, 1885, you wrote to me that at a meeting of the Executive Committee it was voted to proceed at once with the work of reconstruction, and you instructed me to proceed to reconstruct the Omaha Bridge in the manner recommended in my report of May 23. On September 19 I appointed Mr. H. W. Parkhurst Assistant Engineer of Foundations, and directed him to proceed at once to Omaha and take charge of the work. Mr. Parkhurst arrived at Omaha on September 22, and made arrangements for beginning the foundation work immediately. The construction of the new Omaha Bridge really dates from this day. The fact that the work was the reconstruction of an old bridge, over which a heavy train service was to be maintained at all times, made it seem expedient to keep the control of the work as much in the company’s own hands as possible. It was therefore determined to do everything on the ground by day’s work under the immediate direc¬ tion of the engineers, except the building of the masonry, which it was thought best to do by contract. The foundations were put in by the company’s own men by day’s work, and the superstructure was erected in the same manner, the material being manufactured at an Eastern establishment by contract. On October 13 a contract was closed with Messrs. T. Saulpaugh & Company, for the construction of the masonry. On the evening of December n Mr. Parkhurst met with a serious accident in Omaha near his residence, which incapacitated him from work for several months. On December 15 Mr. George A. Lederle took Mr. Parkhurst’s place, and as Resident Engineer continued in imme¬ diate charge of the work until the bridge was completed. The framing of the timber for the caisson for the first pier was begun October 29, and air pressure was put on December 15, the day that Mr. Lederle took charge of the work. On December 7 invitations were sent to nine prominent bridge builders, inviting proposals for the construction of the superstructure; eight of these parties responded. The proposals were opened on De¬ cember 29, and the work was awarded to the Union Bridge Company, as the lowest bidder. The work was continued without interruption from this time for¬ ward, the erection of the last span being finished May 14, 1887. After the first of June, 1887, the difficult part of the work being entirely completed, Mr. Lederle was transferred from Omaha to Portland, Oregon, where he took charge of the bridge across the Willamette River; and Mr. E. Duryea, Jr., was appointed Resident Engineer. The bridge was completed before the connecting tracks were ready on either end, and it was not put in use as a double-track structure until October 1, 1887. On the 10th of November, 18S7, Mr. Duryea and others drove across and returned in a carriage, thus using the carriage-ways for the g093 4 THE NEW OMAHA BRIDGE. first time. On the same day Mr. Duryea turned the bridge over to Mr. V. G. Bogue, Chief Engineer of the Union Pacific Railway; and my connection with the structure ceased. As a preliminary to this transfer, on the third day. of November, 18S7, I addressed a letter to Mr. T. J. Potter, showing in detail what remained to be done. This letter may be found in Appendix G. II. GENERAL DESCRIPTION. The new Omaha Bridge was designed to accommodate both rail¬ road and highway traffic. It is a double-track railroad bridge; the two tracks being placed 12 feet between centers, and the clearance between trusses being 26 feet. The highways are carried on cantilever arms projecting outside the trusses. The new bridge is really a reconstruction of the old bridge, though very little of the old bridge remains. The same approaches are used, and the location is entirely unchanged, while the dimensions of the old structure fixed the dimensions of the new structure. The old bridge was 2,750 feet long, but for several years little or no water had flowed through the four easterly spans. A clear width of 1,000 feet affords ample water-way on this section of the Missouri. In many places where the channel has remained stable for a long series of years, the river has reduced its width between high-water banks to less than this. It was farther decided to limit the water to the space between Piers I. and VI., or to a width of 1,250 feet, the additional 250 feet more than balancing the obstruction offered by the old piers and the piles of riprap around them. The length of the new bridge is, however, 1,750 feet; the 250 feet west of Pier I. and that between Piers VI. and VII. being occupied by an iron structure, though the flood water is entirely excluded therefrom. The cylinders of the old piers are 8^- feet in diameter, having a cross-section of about 57 square feet; the weight of the superstructure being carried directly on the masonry filling and not borne by the iron sjiell. The maximum weight of superstructure and moving load which each of these cylinders was required to bear was at least 300 tons, pro¬ ducing a pressure of about 75 pounds per square inch on top of the cylinders, and of over 200 pounds at the base. These pressures were considered as large as it was wise to use on this kind of work. The old piers had been protected by heavy piles of riprap around them, which made it seem expedient to build the new piers as far from the old piers as possible, where the obstructions to be encountered would be a minimum. This fixed the location of the new piers half-way be¬ tween the old piers. With the possible water-way of the new bridge limited to the space between Piers I. and VI., and with the location of the new piers fixed midway between the location of the old piers, two arrangements were possible: three new piers and two spans of 500 feet each, or five new piers and four spans of 250 feet each. If you had been building an ordinary single-track railroad bridge the former arrange¬ ment would have been preferable; but for the heavy double-track struc¬ ture which has been erected, the latter arrangement was found a little more economical, besides giving very much better facilities for handling the work independently of stages of water, the short spans of less than 125 feet between the old and new piers making it possible to raise without danger at all times. The structure as now built extends from the old masonry pier to Pier VI., — a distance of 1,750 feet. The easterly and westerly spans of this length were subdivided by building two new piers. As these piers are outside the limits within which the flow of the river is confined, it was not thought necessary to go to the expense of putting in deep foundations, and they are founded on concrete at shallow depths. The bridge, therefore, consists of four through spans measuring 1,000 feet between centers of piers, and at each end three deck spans measuring 375 feet between centers of piers, — making the total length, as already stated, 1,750 feet. The east approach is the old approach, which your company have widened for a double track; and the embankment when completed — which I strongly advise be done as soon as possible — will extend to and surround the old Pier VII. The west approach is the old approach widened. Both approaches are on the same tangent as the bridge, and the grade is level from the west end of the west approach to Pier VII., — the east end of the east approach, — from which point a uniform grade of T 6 7 of one per cent descends towards Council Bluffs. The river is now in quite a stable condition, the only danger com¬ ing from the erosion of the east bank, three or four miles above, which tends gradually to throw the bend above the city further down stream. The vested interests in Council Bluffs and elsewhere will, however, prob¬ ably prevent this erosion continuing to a dangerous extent. The west shore is thoroughly protected from the smelting works to the bridge line. The general direction of this shore makes an angle of about 1 io° with the bridge line. It would be very desirable to have this shore line forced forward until it be at right angles with the bridge. The expense of doing this would be pretty large, but it would reclaim from the river an amount of very valuable land worth several times the cost of the work. I fear, however, that this contemplated scheme has since been blocked by the construction of the highway bridge at the foot of Douglas Street. The rectification of the river here is a matter of large importance, not only as regards the bridge, but as regards many other interests. As at other places on the Missouri, the bottom-land slopes lightly away from the river. At the place where the river has been cutting above Omaha, the bottom-land is lower than it is at the bridge site, and the surface of the water is a few feet higher. The danger of overflow to the lower portion of Council Bluffs comes from this place, as a rise of water which would be perfectly harmless at the bridge line would make an overflow three or four feet deep at this place. A location vVas made for a line of levee from Pier VI. to the east bluff above Council Bluffs. This levee is the only sure way of protecting the lower portion of Coun¬ cil Bluffs from the overflow, and it would seem that the united interests of the railroad and the property owners ought to build it. During the conduct of the work all levels were referred to the da¬ tum used during the construction of the old bridge, and this datum was the assumed low water, which, however, is considerably below any low water which has actually been observed, and six feet lower than the low water recently established by the Missouri River Commission. To avoid the use of negatives, this datum was called 100. Therefore, in the elevations used in this report, 100 corresponds to o in the published reports of stages of water, that zero being according to the levels of the Missouri River Commission, 545.61 feet above the St. Louis city direct¬ rix, which is 413.05 feet above mean tide in the Gulf of Mexico. To refer the levels of this report to tide-water, it will be necessary to add 858.66. THE NEW OMAHA BRIDGE. 5 III. SUBSTRUCTURE. The five piers are designated by letters, Pier A being the most easterly. This designation was adopted to avoid confusion with the old piers, which were numbered; the numbering being from west to east. The five piers are founded on pneumatic caissons of the following dimensions: — Pier A, Pier B, Pier C, Pier D, Pier E, 65 feet long, 25 feet wide, and 18 feet high. 65 “ “ 25 “ “ 18 “ “ 66 “ " 26 “ “ 18 “ “ 65 “ « 25 “ “ 18 “ “ 65 “ “ 25 “ “ 18 “ “ The' foundations were put in by the company’s men under the direction of the Engineer. The masonry was built by contract by the firm of T. Saulpaugh & Company. The caisson for Pier A was built on the dry sand-bar on the east side of the river. The other four caissons were built in position on pile false-work, and lowered by long screws to the bottom of the river. The pneumatic machinery was set up on the east side of the river, south of the old Pier VI. It consisted of two No. 4 Clayton Duplex Compressors, the power being supplied by three old locomotive boilers. A Worthington Packed Plunger, Duplex Pump, with 18^-inch steam cylinder and io|~inch water plunger, supplied the power for the sand pump excavators. These sand pumps were of a special pattern designed by me and illustrated on Plate 7. A temporary pile bridge was built each year from the east bank of the river fifty feet north of the bridge line, extending during the first season as far as Pier C, and during the second season completely across the river. A service track was laid on this bridge, and the Worthington pump was then set up on this bridge, steam being supplied from the boilers on the shore. The air for the caissons was led from the pumps to Piers C and D by a pipe laid on the floor of the old bridge; this arrangement being adopted so that the air supply could be kept up in case any injur}' occurred to the temporary pile bridge. During the second season the Worthington pump was put on a barge, and steam supplied by two 60 H. P. portable boilers erected on this barge. After the completion of foundation D the pneumatic machinery was moved from the east sand-bar and set up on the west side of the river. The caissons were built of Oregon fir, with cutting edges of iron, strongly bolted together, and filled with Portland cement concrete. The caisson for Pier A is surmounted by 38 feet of crib-work, that for Pier B by 13 feet of crib-work, and that for Pier C by 6 feet of crib-work ; the crib-work being filled with concrete similar to that used in the caissons. The masonry of Piers D and E starts from the top of the caisson. The framing of the caisson for Pier A was begun October 29, 1885, the erection of the caisson November 6, and air pressure was put on December 15. The laying of masonry began January 11, 1886, and the caisson reached bed-rock at elevation 35.72 on January 31. The sealing of the working chamber was begun February 1, and completed February 8. The masonry was finished April 22, 1886. The framing of the caisson for Pier B began November 27, 1885, the construction of the staging December 2, the erection of the caisson January 5, 1886, and the lowering with screws January 30. On February 5 the caisson rested on the bed of the river, and air pressure was put on February 6. The laying of masonry began February 11, and the caisson reached the rock at elevation 28.62 on March 7. The concrete filling of the working chamber was begun March 9, and finished March 12. The masonry for this pier was completed June 12, 1886. The framing of the caisson for Pier C began June 28, 1886, the construction of the staging July 31, the erection of the caisson Au¬ gust 18, and the lowering with screws September 15. Air pressure was put on September 17, and on the same day the caisson rested on the bed of the river. The laying of masonry began September 23, and the caisson reached bed-rock at elevation 30.07 on October 20. The concrete filling of the working chamber was begun October 24, and finished October 30. The masonry for this pier was completed De¬ cember 18, 1886. After the completion of the foundation of Pier C, it was thought wise to discontinue the work until after the flood season of 1886. The construction of the staging for Pier D was begun September 14, 1886, the framing of the caisson September 15, the erection of the caisson September 23, and the lowering with screws October- 27. Air pressure was put on November 3, and on November 4 the caisson rested on the bed of the river. The laying of masonry began November 4, and the caisson reached bed-rock at elevation 40.80 on December 3. The concrete filling of the working chamber was begun December 4, and finished December 7. The masonry for this pier was completed March 8, 1887. The river closed by ice unusually early, — on November 18, 1886; but it was not thought safe to begin work on the construction of Pier E until the season was so far.advanced that there was thought to be no danger of this ice moving. In the intervening time the pneumatic machinery was moved from the east to the west side of the river. The construction of the staging for Pier E was begun October 19, 1886, and the framing of the caisson was begun on the same day. The erection of the caisson was begun on November 28, and the lower¬ ing with screws began January 5, 1887. Air pressure was put on January 9, and on January 10 the caisson rested on the bed of the river. The laying of masonry began January 12, and the caisson reached bed-rock at elevation 46.43 on February 17. The concrete filling of the working chamber was begun February 19, and finished February 22. The masonry for this pier was completed April 7, 1887. The full details of the five piers, the caissons, the air-locks, and the appliances used in connection therewith, are given on Plates 2, 3, 4. 5> 6, 7, 8, and 9. The rate of progress in sinking is illustrated graphi¬ cally on Plate 10. Full records of the progress in detail of sinking these foundations were kept, and are given in Appendix C. The de¬ tailed cost is given in Appendix D. The concrete used was manufactured in a mixer consisting of a 9-inch spiral conveyor with teeth arranged between the flights, and running in a wrought-iron trough. The sand, cement, and water were mixed in this mixer, and the stone was put in after depositing the con¬ crete mortar in position, the stones being thrown in by hand and the whole mass thoroughly rammed. Inside of the working chamber no stone was used. The proportions of sand to cement varied from two to four parts of sand to one of cement, the cement being Portland cement except in some unimportant instances. The cost of the five foundations is shown in detail in the follow¬ ing table ; this cost including all concrete and other material below the masonry: — THE NEW OMAHA BRIDGE. Charges E ^Freight Freight Chaiges. Cost, excluding ^Freight Freight Charges. FOUNDATION A: FOUNDATION C: Caisson — ’S3 c “Ei,. «a' ¥£s Labor . — 3-53'-59 f 9'3-94 263,521.25 2,039.98 25.45 25.30 5375,o87-87 551,604.81 — ~ 5426,692.68 FOUNDATION A: Caisson and Filling, including Cutting Edge, Crib and Filling.. Sinking Caisson . Erection and Removal of Machinery . . FOUNDATION B: Caisson and Filling, including False Work, e Crib and Filling . . . -.. Sinkiitg Caisson. Erection and Removal of Machinery . . FOUNDATION C: Caisson and Filling, including False Work, e' Crib and Filling. Sinking Caisson. Erection and Removal of Machinery . . FOUNDATION D: Caisson and Filling, including False Work, et Sinking Caisson. Erection and Removal of Machinery . . FOUNDATION E: Caisson and Filling, including False Work, et Sinking Caisson . Erection and Removal of Machinery . . Total Cost of Foundations. Masonry, Pier A. “ “ B. “ “ C. “ “ D. “ “ E. Total Cost of Masonry. Grand Total of Five Piers. THE NEW OMAHA BRIDGE. 9 On the east side of the river the old Piers VI. and VII. were cut down, the cast-iron caps replaced, and the piers adapted to carry the ends of the deck spans. On each side of the river a new pier was constructed, with a concrete base 20 feet by 38 feet 6 inches, supporting two iron cylinders filled with concrete and formed of parts of the old bridge ; the cylinders on the west side have shells of wrought iron; those on the east side of cast iron. These approach piers are shown on Plate 12. The stones of the old masonry pier at the west end of the old bridge were found to be badly injured by frost. The exposed portion of this pier was removed and replaced by first-class work of Man¬ kato stone. Back of this pier a retainer wall was built of Mankato stone, with a concrete foundation to hold the end of the embankment, which the design of the new bridge made much wider than the old embankment. This retainer wall was kept entirely independent of the pier, so that settlement would not disturb the pier ; it settled several inches, and the masonry was badly cracked at the center, but other¬ wise it is still in good order. The amount of masonry and concrete in the entire bridge is as follows: — Cubic Yards. Concrete, Cubic Yards. Total. Pier A. 1,368.62 1,770.2 3,l38-8 Pier B. 2,217.23 1,042.0 3,259.2 Pier C. 2,557.86 888.0 3,445-9 Pier D . 2,232.31 671.0 2 ,9°3-3 Pier E . 2,039.9s 558.0 2,598.0 East Approach Pier. — 236.0 236.0 West Approach Pier. — 157.2 West Approach Retaining Wall .... 33343 93-6 427.0 West Abutment. 77-51 — 77-5 Total, Cubic Yards .... ,0,8^94 5,416.0 ,6,444.9 The total cost of the substructure was as follows: — Five Piers . $426,692.68 East Approach Pier . 3,308.34 West Approach Pier . . .. 1,736.92 West Abutment and Retaining Wall. 9,077.69 Total Substructure .... $440,815.63 The cutting down of old Piers I., VI., and VII. was charged to Removal of Old Works. IV. SUPERSTRUCTURE. The superstructure consists of four through spans and six deck spans, — three on each end. Each through span is 246 feet 2 \ inches long between centers of end pins, and each deck span 120 feet 7^ inches. Expansion is provided for in the through spans by rollers placed on Piers A, C, and E. Expansion is provided for in four of the deck spans by supporting one end on rocking bents which rest on the new approach piers. These bents rock on pins in wrought-iron bolsters resting on the cast-iron caps of the new piers, and secured by long bolts extending into the concrete below; these bolts being of sufficient length to allow of lifting the bolsters in case of a settlement of the piers. 1 In the other two deck spans expansion is provided for by rollers placed on Piers A and E. The entire structure is built for a double track with a carriage-way and footway on each side. The railroad tracks are 12 feet between centers; the carriage-ways 7 feet wide be¬ tween wheel-guards; the carriage and foot ways 12 feet 1 inch between centers of railings; and the entire floor 53 feet 8 inches over all. On the seventh day of December, 1885, a circular was addressed to prominent bridge builders, inviting proposals for the construction of the superstructure. On the twenty-ninth day of December the work was awarded to the Union Bridge Company, as the lowest bidder. The trusses of the through span are divided into eleven panels, of 22 feet 4§ inches each, and are of the double-system Whipple type; the trusses being 40 feet deep and placed 28 feet 6 inches between centers. The top chord, end posts, the eye-bars of the bottom chord, and the heavier portion of the main ties, the bolsters, rollers, bearing plates, and pins are of steel. All other parts are of wrought iron, excepting the heavy wall plates resting on the masonry, the washers, and ornamental work, which are of cast iron. The details of these spans are given on Plates 15, 16, 17, 18, and 19. 1 In the case of the East Approach Pier this was done during construction, the bents and bolsters being raised and thick cast-iron plates put under the wrought-iron bolsters. Each deck span is divided into five panels, of 24 feet 1^ inches each, the trusses being of the single-system Whipple type without end posts, 18 feet deep and placed 18 feet 6 inches between centers; the width being fixed by the distance between the centers of the columns of the old piers. The deck spans , are entirely of wrought iron, excepting the pins, rollers, and bearing plates, which are of steel, and the wall plate pedestals, which are of cast iron. The details of these plans are given on Plates 20, 21, and 22. The trusses were not proportioned to carry any particular class of locomotives or cars now in use, but the moving load on both roadways and railroad was taken at 8,000 pounds per lineal foot of bridge; and in calculating the effects of a moving load the portion of the strain on each member in excess of the strain which would have been produced by a uniform load of equal intensity was taken on a basis of 10,000 pounds per foot. In the through spans the dead load was taken at 5,000 pounds per lineal foot; the total load was therefore 13,000 pounds per foot; and the calculations gave the same aggregate results, except in the counters, that would have been obtained if the moving load every¬ where had been considered as 10,000 pounds per lineal foot and the dead load 3,000 pounds. In the deck span the dead load was taken at 4,000 pounds per foot. The floor system is proportioned for a total load of 6,000 pounds per lineal foot of track throughout. The top lateral system is designed to resist a wind pressure of 300 pounds per lineal foot, and the bottom lateral system 500 pounds per lineal foot. The strains are given on Plate 23. The steel compression members in the top chord and end posts are made as nearly as possible of a balanced section, the metal in the top cover-plate being practically the same as in the two balance plates be¬ low and the lacing. The compression strain on these members was limited to 1 5,000 pounds per square inch of net section ; the net section being obtained by deducting from the gross section the portion of the cover-plate which was in excess of the balance plates, or supposed to be equivalent to the lacing. The maximum tensile strain allowed in the bottom chord was limited to 14,000 pounds per square inch, and somewhat less in the web members. The maximum strain on iron was limited to 10,000 pounds per square inch, and to 8,000 pounds on extreme fibers of riveted girders. IO THE NEW OMAHA BRIDGE. The weights of iron and steel in the through spans are as follows: Four Spans. Average per Span. lbs lbs. lbs. Steel . — 1,540,126 385, 0 3 1 Wrought Iron in Trusses. 961,494 “ “ Railroad Floor .... 955 UI 4 “ “ Highway Floor .... 329,596 Total Wrought Iron .... 2,246,204 561,551 Cast Iron. - 108,160 27,040 Total. - 3,894,490 973,622 The weights of iron and steel in the deck spans are as follows: Six Spans. Average per Span. lbs. Ibs. lbs. Steel. — 30,226 5,038 Wrought Iron in Trusses. 972,426 “ Railroad Floor .... 624,195 “ “ Highway Floor .... 167,869 Total Wrought Iron .... 1,764,490 294,081 Cast Iron. 44,970 7,495 Total. - 1,839,686 306,614 Four Supporting Bents. - 118,650 Total. - •,958,336 The specifications under which the superstructure was manufactured are given in Appendix E. An attempt was made to get steel made by the Clapp-Griffiths process, but the results were entirely unsatisfactory, only 55 very small charges being accepted. The full number of accepted blows of open-hearth steel was 135, which were made by the following parties: — Pittsburg Steel Casting Co., Pittsburg, Pa.. 72 blows. Carnegie Bros. & Co. “ 22 “ Pennsylvania Steel Co., Steelton, Pa. . . 41 “ The eye-bar steel was all made at Steelton. The work was all manufactured by the Union Bridge Company, at their shops in Buffalo, N. Y. Eighteen full-sized eye-bars were tested to destruction, the tests being made in the large testing machine belonging to the Union Bridge Company, at Athens, Pa. The records of these tests are given in Appendix F. This machine being a hydraulic machine, with no weighing apparatus excepting the gauges, cannot be relied upon absolutely for determinations of elastic limit or breaking strain ; but the other qualities, which are the only ones insisted on in the specifications, are exact. The necessity of removing the old bridge and maintaining traffic during the reconstruction made it necessary to adopt a special plan for erection. The deck spans were erected in a simple manner on false¬ work, and were then made use of as a staging for the removal of the old spans. In the erection of the through spans advantage was taken of the small distance between the masonry piers and the old iron piers. The first through span erected was that reaching from Pier A to Pier B. An iron harness was placed on old Pier V. and a similar harness on old Pier IV. Four lines of combination trusses were then erected, supported on the masonry piers and on the harnesses, the bottom chord bars of the old bridge being used in these combination trusses; the two inside trusses carried the traffic during erection and the two outside trusses the new work. This arrangement of four trusses was adopted as an extra precaution in case of accident, it being thought that if one truss were destroyed by an accident the other three would remain in position. Fortunately no such accident occurred. The harness and combination spans are shown on Plate 24. The old trusses were removed by a traveler without the use of upper false-work, and the new trusses were erected in the same manner. The dates at which the several trusses were erected is shown in the following table: — First Iron Placed. Span Swung. First East Deck Span . . . May 18, 1886. May 31,1886. Second “ “ . • . “ 26, “ June 2, “ Third “ “ • • . “ 28, “ “ 3 , “ Through Span A-B . . . . Oct. 2, “ Oct. 9, “ “ “ B-C. . . . Jan. 28,1887. Feb. 14,1887. “ « C-D . . . March 30, “ April 7, “ « « D-E . . . May 9, “ May 14, “ First West Deck Span . . . June 16,1886. June 19,1886. Second “ “ • • “ 17 , “ “ 22, “ Third “ “ . . . April 19,1887. April 24, 1887. The railroad floor system is shown on Plate 19. It consists of 8 by 8-inch ties, 20 to the panel in the intermediate panels of the through spans, and 22 to the panel in the deck spans and the end panels of the through spans, resting on iron stringers 6 feet between centers. Inside the rails are placed two lines of 5 by 4 by f-inch angle iron, bolted to every tie by one-inch bolts and laid to an outside gauge of 3 feet 8 inches. The highway floor is of timber, the wooden stringers being sus¬ tained by short floor beams midway between the panel points, these being supported by the light lattice trusses which constitute the railings. The wearing plank of the floor is of 2-inch oak put on diagonally, and the footway is separated from the carriage-way by a gas-pipe railing. The running of trains was never interrupted for more than two hours at any one time during the entire erection. The double track was first used on October 1, 1887. At your request symbolic figures were placed at each end of the superstructure. That at the east end is a colossal bronze buffalo head, which was modeled by Captain Edward Kemeys, of Perth Amboy, N. J., and cast by Mr. Etienne Favy, of New York City, this symbol being understood to represent the wildness of the plains which the travelers are approaching. The device at the west end is a bronze bas-relief showing a plow, anchor, and steam hammer, as symbolic of the agricul¬ ture, commerce, and manufactures of the East. THE NEW OMAHA BRIDGE. The total cost of the superstructure is shown in the following table: — Main Spans. Iron, Steel, and Ornamental Work .... Freight Charges on same from Chicago . . Labor, — Handling Iron in Yard .... Erection of Spans ...... Erection and Removal, Engines and Derricks. Switching Charges. Coal. Traveler, — Material and Labor. Harness, “ “ False-Work, “ “ ...... Combination Spans, — Framing, Erection and Removal, and Diagonal Bars . . Miscellaneous Material, — Rope, Iron, Steel, Cement, Oil, Waste, etc. Total Main Spans. Approach Spans. Iron and Steel. Freight Charges on same from Chicago Labor, — Handling Iron in Yard . . Erection of Spans .... Switching Charges. False-Work, — Labor and Materials Total Approach Spans Railroad Floor. Materials. Labor . Total Railroad Floor . . Roadway Floor. Materials. Switching. Total Roadway Floor Materials. Labor. Total Painting .... Total Superstructure . $132,193.16 5,586.89 $137,780.05 3,220.22 — I4,I05.+4 — 599.98 2,344-91 433-9° 679-34 1,198.64 — 3.89S-33 - 7,473-13 $172,765.01 62,498.85 — — 6,605.93 — 74°-i3 39.60 76,402.85 9,898.04 2,655.11 12,553-15 15,534.80 5,516.15 1,270.14 22,321.09 1,607.72 — 6,119.62 - - $290,161.72 V. APPROACHES. The portion of the east approach included in the reconstruction of the Omaha Bridge extended only from the east end of the embankment to the east end of the iron-work of the new bridge; that is, it occupied the space of the four easterly spans of the original bridge. The west approach was understood to extend from the west end of the bridge to the under crossing of the carriage-way. The* embankment east of the bridge was widened by the operating department to adapt it for a double track; but this does not appear in any of my accounts. The easterly span of the old bridge, between Piers X. and XI., was never replaced after it was blown down in 1877. The old trestle which replaced this span was repaired, widened, and adapted to carry a double track temporarily. The three next spans were replaced by substantial double-track timber trestles. Advantage was taken of the shortening of the bridge to extend the grade on the east approach to the end of the iron-work. This grade was originally laid out as a An r P er ' cent grade (35 feet per mile), but the embankment was never completed, and the portion next to the bridge was about a iy 5-per-cent grade. As revised, the grade is made T Vper-cent for the entire length. It was intended to fill the timber trestle during the progress of the work, but various circumstances prevented its being done. An embankment was built, however, the full width and finished at eleva¬ tion 124, or 1.21 feet above the high water of 1881, and the exposed slopes of this embankment were riprapped. I should strongly advise your company to fill the entire trestle as early as can conveniently be done. The embankment on the west approach, from the west end of the bridge to the under crossing of the carriage-way, was widened with teams and adapted to a double track. The roadway approaches are carried down on each side of the rail¬ road approaches at each end of the bridge, with a 5-per-cent grade, to points where the difference in elevation is such that the south roadway can be carried under the railroad tracks and connected with the north roadway, from which point of intersection the united roadways are extended to connections with surface roads. On the east side, these roadways are of trestle to the point where they unite, and an earthwork embankment from there down. On the west side, the entire roadway approaches are solid embankments, which are paved with sandstone blocks from the end of the bridge to the point where the two road¬ ways unite. Simple toll-houses were erected at the points where the two roadways unite. The general arrangement of these roadways is shown on Plate I. VI. COST. The cost of the bridge and approaches is shown in the following table. The item of freight includes generally the freight from Chicago to the bridge site, from the sawmills to the bridge site, and from the quarries to the bridge site. In comparing the cost of this bridge with that of other structures, the cost without freight forms the most cor¬ rect basis for comparison. OMAHA BRIDGE. This table may be condensed into the following: — Cost, exclusive of Freight Charges. Freight Charges. Cost, including Freight Charges. Substructure. $386,622.19 S54, 1 93-44 $440,815.63 Superstructure. 276,982.16 I3,I79-S6 290,161.72 Total, Bridge Proper .... 663,604.35 67,373-00 730,977-35 Approaches. 84,571.56 - 9,354-58 93,926.14 Buildings, Tools, and Service Track . . . 27,668.80 735-76 28,404-56 Engineering and Expenses. 34,920.46 - 34,920.46 Total Cost. 810,765.17 77,463-34 888,228.51 Less Value of Material Sold less Cost of removing sam^. - - 43,860.61 Total Net Cost. - $844,367.90 In my report of May 23, 1885, the total cost of the new work within the length of the old bridge was estimated at $880,000; this providing for a solid embankment in place of the existing trestle at the east end of the bridge. The cost above stated includes $20,994.99 expended west of the length of the old bridge, leaving the actual expenditure within the limit covered by the estimate $824,272.91; the saving from the estimate being about double the amount that will be required to build the embankment. 13 APPENDIX A. LIST OF ENGINEERS, EMPLOYEES, AND CONTRACTORS. ENGINEERS AND COMPANY’S EMPLOYEES. NAME AND OCCUPATION. TIME OF SERVICE. Geo. S. Morison, Chief Engineer. Geo. A. Lederle, Resident Engineer. Dec. 16, 1885, to June 1, 1887. H. W. Parkhurst, Assistant Engineer of Foundations . . Sept. 19, 1885, “ Dec. 15, 1885. Lewis Blickensderfer, Assistant Engineer. Oct. 26, 1885, “ Mar. 31, 1S86. Ralph Modjeski, Assistant Engineer . Oct. 16, 1885, “ Aug. 15, 1887. E. P. Butts, Inspector at Quarries and Assistant Engineer Feb. ro, 18S6, “ Mar. 15, 1887. M. A. Waldo, Assistant Engineer . Sept. 1, 18S6, “ Nov. 24, 1886. G. J. Bell, Assistant Engineer. Nov. 25, 1886, “ Jan. 20, 1887. E. Duryea, Jr., Resident Engineer. June 7, 1887, “ Nov. 17, 1S87. S. W. Y. Schimonsky, Draughtsman. Aug. 10, 1886, “ Apr. 15, 1887. Alfred Noble, Chief Inspector of Superstructure .... Feb. 8, 1886, “ June 30, 1886. R. W. Hildreth, Inspector of Superstructure. Mar. 1, 1886, “ July 31, 1887. James Saguin, Foreman of Erection . April 1, 1886, “ May 31, .887. Robert Ross, Inspector of Masonry . Jan. 15, 1886, “ Mar. 31, 1887. Dennis Brophy, Master Mechanic . Oct. 9, 1885, “ July 6, 1887. Patrick Aylward, Foreman of Pressure Work. Nov. 5 . «S8 S , “ Feb. 10, 1886. Dennis Leonard, Foreman of Pressure Work. Feb. 11, 1886, “ Feb. 27, 1887. William Wride, Sub-foreman of Erection . May 2, 1886, “ Aug. 17, 1887. CONTRACTORS. NAME. NATURE OF WORK. T. Saulpaugh & Co .Masonry. Chas. Stears, Foreman of Masons. Oliver W. Davis, Foreman of Stone-Cutters. Union Bridge Co.Superstructure. Walter A. Smith. Earthwork of Roadway Approaches. APPENDIX B. SPECIFICATIONS FOR MASONRY. The masonry will be first-class rock-face work laid in regular courses. The face stones above an elevation designated by the Chief Engineer, and including the coping, will be of granite from the quarries near St. Cloud, Minn. All other work will be of limestone from the quarries at Mankato, Minn., except spalls for backing, which shall be furnished from such source as shall require the least transportation. The piers shall conform in all respects to the plans furnished by the Engineer. No course shall be less than 16 inches thick, and no course shall be thicker than the course below it. The upper and lower beds of every stone shall be at least one quarter greater in both direc¬ tions than the thickness of the course, and no face stone shall measure less than 30 inches in either horizontal direction. In general, every third stone of each course shall be a header, and there shall be at least three headers on each side of each course between the shoulders. No stone will be considered a header that measures less than 5 feet back from the face. The headers shall be so ar¬ ranged as to form a bond entirely through the pier, either by bonding against a face stone in the opposite side of the course, or by bonding with a piece of backing of the full thickness of the course and not less than 3 feet square, which shall bond with a face stone on the oppo¬ site side. In all cases the interior bonding shall be further secured by placing in the course above a stone of the full thickness of the course, and at least 3 feet square, over the interior joints. Special care shall be taken with the bonding of the ice-breaker cut-water, the stones of which shall be so arranged that the face stones are supported from behind by large pieces of backing. All joints shall be pitched to a true line, and dressed to $ of an inch for at least 12 inches from the face. Beds, both upper and lower, shall be pitched to a true line and dressed to J of an inch. Joints shall be broken at least 15 inches on the face. The bottom bed shall always be the full size of the stone. The pointed up-stream starlings of all the piers, for a height of 30 feet, terminating under the small coping at the offset, shall have a fine pointed face with no projection exceeding J inch from the pitch line of the joints. There shall be a draft line 3 inches wide around the lower edge of the belting course below the coping and on the edge of the pointed starlings. The entire coping over the whole pier, and the small copings over the starlings, shall have smooth, bush-hammered surfaces and faces. All other parts of the work shall have a rough quarry face, with no projections exceeding 3 inches from the pitch line of the joints. The stones in the coping under the bearings of the trusses shall be at least 3 feet wide, and shall reach entirely across the pier. They shall have good beds for their entire size, and shall have a full bearing on large stones with dressed beds in the belting course below the coping. The stones of the backing shall have dressed beds, and the backing shall be leveled up true with the face stones on the completion of every course. The backing shall generally be the same thickness as the face stones, but two thicknesses of backing may be used for one course of face stones, provided no backing is less than 12 inches thick. All stones shall be sound, free from seams and other defects, and all limestone shall be laid on the natural bed. All stones shall be laid in full mortar beds. They shall be lowered on the bed of mortar, and brought to a bearing with a maul. No spalls will be allowed except in small vertical openings in the backing. Thin mortar joints will not be insisted on, but the joints shall be properly cleaned on the face and pointed in mild weather, the pointing to be driven in with a calking iron. The face stones of each entire course for the same height as the bush-hammered coping over the starling shall be doweled into those of the course below, with round dowels of ij-inch iron extending 6 inches into each course; the dowels shall be from 8 to 12 inches back from the face, and 6 inches on each side of every joint; the stones of the upper course shall be drilled through before setting, after which the drill hole shall be extended 6 inches into the lower course; a small quantity of mortar shall then be put into the hole, the dowel dropped in and driven home, and the hole filled with mortar and rammed. The three courses below the cop¬ ing shall have the joints bound with cramps of |-inch round iron, 20 inches long between shoulders, the ends sunk 3 inches into each stone. The mortar will be composed of cement and clean, coarse sand, satisfactory to the Engineer, in proportions varying from one to three parts of sand to one of cement, as may be directed by the Engineer for different parts of the work. When stone is laid in freezing weather the con¬ tractor shall take such precautions to prevent the mortar freezing as shall be satisfactory to the Engineer. The stone shall be cut at the quarries. No material shall be measured, or included in the estimate, which does not form a part of the permanent structure. The railroad company will furnish free transportation from the quarries to the bridge site for stone actually used in the work. Any stone transported and left over will be the property of the railroad company. The railroad company will furnish the cement for the mortar; all other materials shall be furnished by the contractor, who will also be required to furnish all tools of every description both at the quarries and on the work. APPENDIX C. 15 RECORD OF SINKING CAISSONS. PIER A. APPENDIX C. — Continued. RECORD OF SINKING CAISSONS. PIER B. i7 APPENDIX C. — Continued. RECORD OF SINKING CAISSONS. PIER C. i8 APPENDIX C. — Continued. RECORD OF SINKING CAISSONS. PIER D. *9 APPENDIX C. — Continued. RECORD OF SINKING CAISSONS. PIER E. 20 APPENDIX D. TIME, COST, AND MATERIALS USED IN FOUNDATIONS. PIER A. -$10,090.37 APPENDIX D. — Continued. 21 TIME, COST, AND MATERIALS USED IN FOUNDATIONS. PIER B. Other expenses charged to Sinking 22 APPENDIX D. — Continued. TIME, COST, AND MATERIALS USED IN FOUNDATIONS. PIER - ^Night p ssr 1 C ° ff M Sugar. Candles. istis. Coal for Heating. Li o" ed Sacking out Material. M& L™. SfSS firemen at Firemen ^ Col! for PumpBoikr, w 3* Tallow. Waste. OU 1 *5S? j§ 5* Material. Worthington pressors. I J I 1 1 1 i i 5 I | j 3 ! 5 J j J | £ < J - 1 u i < i ! 1 ! i? I < | § < i. ! 0 | | j I 1 i | § j 5 -5 2 I 1 & I I a < 1 u i|J iSS6. Sept. 18 'o 2 3 2 4 26 2 1 3° Oct. 3 1 5 6 I 9 >3 II tS 19 =3 i 27 29 30 $10.50 5.00 5.00 5-00 5.00 5.00 5-oo 5-00 5 00 5-00 5.00 5.00 5.00 5.00 5-QO 5-oo 5.00 5.00 5.00 5.00 5.00 5.00 5.00 5-oo 5.00 5-oo 5.00 5.00 ; 83-85 3-5° 3-5° 3-50 3-5° 3-50 3-5° 3-5° 3-5° 3-5° 3-50 3.50 3-5® 3-5° 3-50 3-5° 3-50 3-5° 3-5° 3-5° 3-5° 3-5° 3-5° 3-5° 3-5° 3-5° 3-75 3-75 3-75 3-75 3-75 3-75 3-75 3-75 3-75 3-75 3-75 3-75 3-75 3-75 3-75 3 75 5-3 3 3 3 3 3 1 3 3 3 i 3 3 5 3 L 0 6 p-5 5 S'S-g 900 9-75 9-75 9-75 13-00 13.00 13.00 13.00 13.00 13.00 .<5.2° -45 =9-75 14.00 1 $7.20 4.50 4.50 4.50 4.50 4.50 4.50 4-50 4.50 4- 5° 4.50 4.50 5.00 5.00 500 5.00 5.00 5.00 54m 5.00 5.00 5- 5° 5.50 5.50 5-5° 5.50 5-5° 5-5° 5.50 5.50 5.50 5.50 5.50 5-5° 5.50 5.50 5.50 5.50 3°-4 29.0 27.0 27.0 27.0 27.0 27.0 25.2 3S-o 34-0 34- o 35- o 360 36- 4 56.1 45- 2 32.0 49-0 30.0 32.0 33-o 33-o 32.0 320 32.0 32.0 32.0 31 0 30.5 36S.40 51-75 81“ 60.75 60.75 60.75 60.75 60.75 60.75 60.75 60.75 60.75 65.50 65-5° 87-5° &5.00 S5.00 S5.00 87-5° 90.00 91.00 140.25 124.30 SS.00 If SS.00 90.75 S S8.00 SS.00 S8.00 Ssloo 85-=5 83-87 1 Sl-75 3-5° 3-5° 3-5° 3-5° 3-5° 3-5® 3-5° 3-5° 3-5° 3-5° 3-5° 3-50 3-5° 3-5° 3-5° 3 50 3-50 3-5° 3-50 3-5° 3-5° 3-5° 3-5° 3-5° 3-5° 3-5° 3-5° 3-5° 3-5° 3-5° 3-5° 3-5° 3-50 3-5° 3-5° 3-5° 3-5° 3-50 3-5° 3-5° 3-5o 3-5 3 i 3 3* i 1 i 45 i 3 3 3 5 2f 3 z i 3 3 3 $0.48 -I ■48 t '.lo .60 .60 1 .72 •72 .s.| •84 .84 .84 ■84 .78 •S 1 1 1.14 1.02 'IV. .66 I4S ■( >0 % .72 -48 3 3 '4 .6 6 6 6 5 5 5 l 7 7 9 9 34 6 6 5 5 5 ■1 S 5 5 5 80.20 40 •34 -27 .40 •34 ■34 •34 47 1 •47 l6l .6t •23 •27 ■41 •33 •27 -34 ■34 ■34 •34 •34 •33 •34 1 9 4 1 5 80.99 .07 ■'3 .05 •23 0., .04 •09 •23 •05 .09 .16 •29 ■34 .09 .14 •09 9 817-5° 7.65 •85 , _ 85 5-95 25 25 25 25 $..Si i-Si 1.81 J 7 ■4 3 |l 1 ?l 1 II 1 1 ° 1 1 1 1 1 III 1 1 1 q 1 1 II 1 1 1 1 1 1 1 1 1 1 1 1 1 1 | 2.4 <0 (O .40 •39 •4° ■39 .40 •39 •39 .40 .40 -jo •4‘ •4° 4° •43 •44 •44 .40 •39 4 i 1 ......................... 1114111 & 111 if 3-3 3-3 S 3-2 3 - 7 ;.6 4.2 4 - 2 3-3 3-4 85-77 5-77 15*77 also *fS 7-35 $ 4.00 4.00 4-oo 4.00 4-oo 4.00 4-00 ■ $2.50 2.50 2.50 2.50 2.50 2.50 2.50 2.50 2.50 2J0 2.50 2.50 2.50 2.50 2.50 2.50 2.50 2.50 2.50 2.50 2.50 2-5° 2.50 2-5° 2.50 2.50 2.50 2.50 2.50 2-5° 2.50 2.50 2.50 3.50 =■50 2.4 2.4 2-4 2.4 2.4 2.4 2.4 2.4 2.4 $11.37 5-77 6.60 6.60 6.60 6.60 6.60 6.60 6.60 6.60 6.60 6.60 6.60 6.60 6.60 6.60 6.60 6.60 6.60 6.60 6.60 6.60 6.60 6.60 6.60 6.60 6.60 6.60 6.60 6.60 6.60 6.1 0 6.60 6.60 6.60 6.60 6.60 6.60 6.60 I.s 2-4 2-4 2-4 2.4 2.4 2.4 2.4 2.4 2.4 2-4 24 2.4 ols 0.9 0.9 SI 8+95 6.60 6.60 6.60 6.60 6.60 6.60 6.60 6.60 660 6.60 6.60 6.60 6.60 6.60 6.60 6.60 6.60 6.60 6.60 6.60 6.60 6.60 6.6a 6.60 6.60 6.60 6.60 6.60 6.60 6.60 6.60 6.1 io 3-3° 2.47 2.48 24S 3-5 2., 2‘ 2- 2-4 24 2.. 2., 2.4 2- 2.. 2.4 2-4 2-4 2.4 2-4 2.4 2-1 2-1 2.4 -'-I 2-t 2-1 2-1 2-1 2-4 2.4 2-4 2-4 2-4 $7.00 4.S0 5-i7 4.S0 4.S0 4.S0 4.S0 4.S0 4.S0 4.S0 4.S0 4.S0 4.80 4.80 •l.i 4.S0 4.S0 4.S0 4.S0 4.80 4.80 4.S0 4.S0 2 4.S0 4.S0 2 4.S0 2 4.80 2 4.50 2 .(.So 2 4.80 2 4.50 2 4.50 2 4.80 2 4.S0 2 4.S0 2 4.S0 2 4.S0 2 4.S0 12 4.80 2 4.S0 2 i .4 4.S0 .4 4.S0 .4 4.S0 .4 4.S0 .4 4.S0 .4 4.S0 .4 4.80 .4 4.S0 .4 4.80 4 4.S0 4 4.S0 4 4.80 4.80 4 4-So 4 4.S0 4 4.S0 4 4.So 1 4.80 4-So 1 4.S0 1 4-So 1 4.80 i 4.80 4.S0 4.50 4.80 4.80 4.50 480 4.50 4-So 4S0 ( 4-So 1 4-So 4.S0 1 4-So t 4-So 4-So 2-5 1 •- '•5 '•5 i.6 1- 7 '•5 2- 3 3- o 3 0 3-5 2-5 2-5 2-5 2-5 2- 5 3- o 2-5 2-5 2- 5 3- o 3-o 3° 3° 3-o 3-o 3-o 4.0 3-o 2-5 i-5 $6.62 3-98 3-97 5-3° 3-98 3-97 5-3° 5-3° 5-3° 5-3° 4.50 j.98 7-95 IS 7-15 6.63 6.62 6.63 6.62 6.63 6.62 6.63 6.62 5-S3 7-95 7-95 7-95 7-95 7-95 7-95 7-95 ro 60 10.60 7-95 5-3° 5-3° 3-98 ts ■|.9 4-h 2-3 2-: 2-S 2.9 2.9 2- 9 2.9 2.9 2.9 2.9 2.9 3- o | 3-6 3-7 n 3-7 3-5 3-6 3.6 3-6 3-6 1-6 0.9 o-9 2.') $1 ! s 9 9 S 9 9 3 3 •'3 •13 •13 •72 ■72 •Vi .36 I 68 § 3 >5 95 54 50 51 54 54 :t 28 4 54 1 I 5 a 1 9 — — 8 $0.47 5i -3° 5 -29 3i 1>9 « S •29 34 -33 3i -32 :?i 64 -39 ■47 5 .35 I .32 •35 s? ! s: , -35 2 J -32 1 1 -44 1 . M : j . J -32 i 4 -33 1 .29 1 •3i 1 •35 2 :S: .23 2 .23 2 •47 3 .23 1 $0.50 f i'i •07 •14 .07 ■14 .14 ■oS .07 S 1 •'3 -12 •13 •12 •'3 o 9 9 S0.54 61 -39 5 -30 3 -iS 5 -3° 5, .30 f 'S 3i -21 •30 lis f 9 6 .36 .4S 1 -5' ' 4 -45 1 1 -39 1 1 -45 1 >4 -39 * .36 1 .48 1 .42 1 4 -33 1 1 -45 ' f -5i 1 1 -39 1 1 -45 ' I -33 - 5 -27 1 ir .'Is ■ IS •is 4 S0.04 .06 4 .05 1 3 ; 3 j i :5j .06 .09 I06 .06 .06 •oS •07 a •03 •03 -03 ■03 •°3 •03 I o- 4 loj .03 •03 $168.59 123.22 129.85 I39.SS IS® I^'i: 129.10 '30-73 146.S2 129.S8 130-89 *37-50 *39-75 '37-43 172.39 167-55 161.47 167-45 178-37 172.14 1S3.66 194.92 235-52 176.17 '45-8 1 231.58 174.65 171.99 178.72 174-56 16S.51 n S.X; &£ 1 58-57 J56-56 15776 14879 346 4-2! 3-3; 1.68 3-6. 3-3' 4.06 0.45 2.35 4.21 2.64 2.86 2.90 280 0.16 2.65 2.50 2-54 Hi i-57 Fine sand. Fine sand. Gravel and sand. Coarse gravel and Gravel, sand, and 23 | | 223 =4 24 22J 24 i64 16I ■7l f 16 s 6 1 3 f 38 39 43 ; 34 40 37 35 43 45 8 39 32 45 43 43 43 35 35 31 35 3° 32 3* 3° 32 35 33 26 34 36 39 37 40 45 45 49 48 52 49 46 53 52 45 15 16 Is 14 Is Is 28 40 50 38 40 3s 30 I 48 52 5° I 5; 46 S' 1 ! 6.2t 10.50 11.50 11.50 ' 8 - 5 : [3-5^ 18.50 21.50 21.50 27.50 29.00 30.00 31.00 3*-oo 3'-5° 32.00 32.00 33.00 34-00 34-oo 34 5° ■>5-5° 6.50 7.00 7.00 7.00 7.00 7-00 7.00 7-oo 7.00 6.00 |.CO 5.00 5-oo Air pressure put on at 5 p. M. on the 17th. Pump started at 10 A. M. Screws removed Pump stopped: waiting for masonry. Strong wind. Caisson landed on bed-rock at 5.20 p. M. loth compressors running during iS hours with 36 revolutions per minute. Pressure taken off at 9 A. M. on the 31st. 220.50 >55->o 576.50 220.20 | 34S0.32 45.22 0.42 5-44 4.12 32.80 8.12 ..36 H 0.63 SS.88 107.50 2SS.46 253-55 |zo8-97 ; O.Sy 41-93 13-72 4-53 1*3-65 .... 0.53 6893.22 1 1 ' Other expenses charged to Sinking 8 '9-93 2 3 APPENDIX D. — Continued. TIME, COST, AND MATERIALS USED IN FOUNDATIONS. PIER D. -— 55.766.7= 24 APPENDIX D. — Continued. TIME, COST, AND MATERIALS USED IN FOUNDATIONS. PIER E. Other expenses charged to Sinking.1147.43 APPENDIX E. 25 SPECIFICATIONS FOR SUPERSTRUCTURE. GENERAL DESCRIPTION. The Superstructure will consist "of four through spans and six deck spans, all built to carry two railroad tracks and two independent roadways. Each deck span will be 120 feet 7A inches long between centers of end pins, divided into five panels of 24 feet ih inches each, the trusses being 18 feet deep and placed 18 feet 6 inches apart between centers. In two spans the expansion for temperature will be provided for by steel rollers ; the other four spans will rest at one end on iron bents, with a rocking pin bearing at top and bottom. The deck spans will be entirely of wrought iron, except the pins, rollers, and bearing plates, which will be of steel, and the wall plate pedestals, which will be of cast iron. Each span will contain approximately 308,000 pounds of wrought iron and steel, and each bent 27,000 pounds. Each through span will be 246 feet 25 inches long between centers of end pins, divided into eleven panels of 22 feet 4$ inches each. The trusses will be 40 feet deep and placed 28 feet 6 inches apart between centers. The roadways will be carried on cantilever arms outside the trusses. The top chord, end posts, the eye-bars of the bottom chord, and a portion of the main ties, the bolsters, rollers, bearing plates, and pins will be of steel; all other parts will be of wrought iron except the wall plate pedestals and ornamental work, which will be cast. Each span will contain approximately 392,000 pounds of steel, 526,000 pounds of wrought iron, and 27,000 pounds of cast iron. The total estimated weight of the entire structure is approximately 5,700,000 pounds. PLANS. Full detail plans, showing all dimensions, will be furnished by the Engineer. The work shall be built in all respects according to these plans. The contractor, however, will be expected to verify the correctness of the plans, and will be required to make any changes in the work which are necessitated by errors in these plans, without extra charge, when such errors could be dis¬ covered by an inspection of the plans. The dimensions given for rivets on the plans are the diameter of the rivet before driving; the rivet hole will be of an inch larger than this diameter, unless otherwise specified. MATERIALS. All materials shall be subject to inspection at all times during their manufacture, and the Engineer and his inspectors shall be allowed free access to any of the works in which any portion of the material is made. Timely notice shall be given to the Engineer so that his inspectors may be on hand. Steel. — The steel used will be of two classes : High steel, which will be used in the compres¬ sion members, bolsters, bearing plates, pins, and rollers ; and Low steel, which shall be used for tension members and rivets. The amount of phosphorus shall not exceed ygg of one per cent. No special method of manufacture will be insisted on, provided the steel meets the conditions of the specifications, but all steel manufactured for one class of work shall be made by the same process and at the same works. A small ingot shall be cast from every melt when the melt is half poured, and a sample bar 3 of an inch in diameter shall be rolled from this ingot ; the tests shall be made on this bar in its natural state, except the second bending test for low steel, which shall be made on this bar after heating to a bright red and immersing in water of a temperature not higher than ioo° Fahr.; if the test bar fails to meet the requirements of the laboratory tests, the whole charge shall be rejected. The laboratory tests of high steel made on the sample bars f of an inch in diameter shall show an elastic limit of not less than 50,000 pounds, an ultimate strength of not less than So,000 pounds per square inch, an elongation of at least 15 per cent in a length of 8 inches, and a reduced area of at least 35 per cent at the point of fracture. In a bending test, the sample bar shall bend 180° around its own diameter without showing crack or flaw. The laboratory tests of low steel made on the sample bar f of an inch in diameter shall show an elastic limit of not less than 40,000 pounds, an ultimate strength of not less than 70,000 pounds per square inch, an elongation of at least 18 per cent in a length of 8 inches, and a reduction of at least 42 per cent at the point of fracture. In a bending test the sample bar shall bend 180°, and be set back against itself without showing crack or flaw; in a second bending test the quenched bar shall bend 180° around its own diameter without cracking. The softest melts shall be selected for rivets, and no fixed elastic limit nor ultimate strength will be insisted on. Facilities for testing the sample bars shall be furnished by the contractor at a point convenient to the steel works, and the tests shall be made at the expense of the contractor and under the direction of the Engineer. The steel plates for compression members shall be rolled in a universal mill. All sheared edges on steel work shall be subsequently planed. Steel for pins shall be sound and entirely free from piping. Wrought Iroti. — The iron used in tension members shall be double-refined iron, rolled twice from the puddled bar. Small samples, having a minimum length of 8 inches, shall be furnished by the contractor for testing, as directed by the Engineer; these samples shall show an elastic limit of at least 26,000 pounds, and an ultimate strength of at least 50,000 pounds per square inch, shall elongate at least 15 per cent, and shall show a reduced area of at least 25 per cent at the point of fracture. The fracture shall be of uniform fibrous character, free from crystalline appearance. Small samples, having a minimum length of 8 inches, shall be furnished by the contractor from the iron used in shapes, plates and other miscellaneous forms, as directed by the Engineer; these samples shall show an elastic limit of at least 24,000 pounds and an ultimate strength of at least 47,000 pounds per square inch, shall elongate at least 10 per cent before breaking, and show a reduction of area of at least 15 per cent at the point of fracture. In plates, more than 30 inches wide an elongation of 8 per cent and a reduction of 12 per cent at the point of fracture will be considered satisfactory. Cast Iron shall be of the best quality of tough, gray iron. RIVETED WORK. The riveted steel work of the trusses shall be punched with holes not larger than of an inch in diameter; the several parts of each member shall then be assembled, and the holes shall be reamed to j-g of an inch in diameter, at least of an inch being taken out all around ; the sharp edge of the reamed hole shall be trimmed so as to make a slight fillet under the rivet head, and the pieces shall be riveted together without taking apart. All rivets in steel members shall be of steel ; they shall be of such size that they will fill the hole before driving, and, whenever pos¬ sible, shall be driven by power. All bearing surfaces shall be truly faced. The chord pieces shall be fitted together in the shop in lengths of at least five panels, and marked; when so fitted there shall be no perceptible wind in the length laid out. The pin holes shall be bored truly, so as to be at exact distances, parallel with one another and at right angles to the axis of the member. All wrought-iron work shall be punched accurately with holes ^ of an inch larger than the size of the rivet, and when put together a cold rivet shall pass through every hole without reaming. So far as possible all rivets shall be driven by power. The holes for the rivets connecting the floor-beams with the posts and bolsters, and the stringers with the floor-beams, and, in general, the holes for all rivets which must be driven after erection, shall be accurately drilled to an iron templet. The holes for the rivets connecting the floor-beams with the posts shall be 1 inch in diameter, and the rivets of corresponding diameter. The pin holes in the vertical posts shall be truly parallel with one another, and at right angles to the axis of the posts. 26 AP PE N DIX E. — Continued. Power riveters shall be direct-acting machines, capable of exerting a yielding pressure and holding on to the rivet when the upsetting is completed. All plates, angles, and channels shall be carefully straightened before they are laid out; the rivet holes shall be carefully spaced in truly straight lines; the rivet heads shall be of hemispheri¬ cal pattern, and the work shall be finished in a neat and workmanlike manner. Surfaces in contact shall be oiled before they are put together. FORGED WORK. The heads of steel eye-bars shall be formed by upsetting and forging into shape by such process as may be accepted by the Engineer. No welds will be allowed. After the working is completed, the bars shall be annealed by heating them to a uniform dark-red heat throughout their entire length and allowing them to cool slowly. The heads of iron eye-bars and the enlarged ends of screws in laterals and counters shall be formed by upsetting or by upsetting and welding by a process acceptable to the Engineer. Welds in the body of the bar will not be allowed. The heads of iron eye-bars shall be made of the dimensions shown on the drawings. The form of the heads of steel eye-bars may be modified to suit the process in use at the contractor’s works, but the contractor will be required to furnish evidence that the form of head which he prefers to adopt is such that it may be relied upon to break the body of the bar, and the acceptance of such modified form of head will not relieve the contractor from any responsibility as to the result of the tests. Steel eye-bars of the same section will be accepted in place of iron eye-bars at a price not exceeding that of the iron. MACHINE WORK. ground for condemnation if it does not occur in more than one third of the bars tested. Should the contractor on the first attempt fail to make bars coming up to the required specifications, the Engineer may order bars of 20 per cent larger section than the plans call for, to be furnished by the contractor without charge for the increased weight. MISCELLANEOUS. All workmanship and material, whether particularly specified or not, must be of the best kind now in use in first-class bridge work. Flaws, ragged edges, surface imperfections, or irregular shapes will be sufficient ground for rejection; rough and irregularly finished work will not be accepted. Machine-finished surfaces shall be coated with white lead and tallow before shipment; all other parts shall be given a coat of hot boiled linseed oil. TERMS. Monthly estimates will be made at the end of each month for the work done during that month. In these monthly estimates, the material delivered at the contractor’s shop, but not manufactured, shall be estimated at 50 per cent of the contract price for finished material in Chicago, and manufactured material at 75 per cent of the contract price for finished material in Chicago. Payments will be made on or about the 15th day of the following month, according to these estimates, deducting from the amount of the same 10 per cent as security, to be held until the completion of the entire contract. No material will be paid for which does not form a part of the permanent structure. All expense of testing shall be borne by the contractor. The bearing surfaces in the top chord shall be truly faced. The ends of the stringers and of the floor-beams shall be squared in a rotary facer. All surfaces so designated on the plans shall be planed. All pins shall be accurately turned to a gauge, and shall be of full size throughout; pin holes shall be bored to fit the pins, with a play not exceeding of an inch. These clauses apply to all lateral connections as well as to those of the main trusses. Pins shall be supplied with pilot nuts for use during erection, four for each size of pin. All screws shall have a truncated V thread, United States standard sizes. TIME. The first deck span, with one bent, shall be completed and ready for shipment not later than April 1, 1 886, and the other deck spans and bents shall follow at intervals of two weeks each. The first through span shall be completed and ready for shipment by June 1, 1886. The other three through spans will be required in November, 1886, and January and March, 1887, respectively. ’ ’ ’ The railroad company may exact a penalty not exceeding £150 per day for failure to com¬ plete the work in these specified times. TESTS OF FULI^SIZED BARS. Ten full-sized steel eye-bars of sections and lengths used in the actual work shall be selected by the inspector for testing; each of these lull-sized bars shall be strained till an elongation of 10 per cent is obtained, and if possible broken; if broken, the fracture shall occur in the body of the bar, and shall show a uniform and ductile quality of material. Six full-sized iron eye-bars of sections and lengths used in the actual work shall be selected by the inspector for testing; each of these full-sized bars shall be strained till an elongation of 10 per cent is obtained, and if possible broken; if broken, the fracture shall occur in the body of the bar, and shall show a uniform, fibrous material. The contractor will be required to furnish facilities for testing the full-sized bars within a reasonable distance of his works. Should the contractor be unable to furnish such facilities, he shall be required to furnish bars of 20 per cent larger section than those called for, without charge for the increased weight. The full-sized bars shall be selected from time to time as the work proceeds, the last bar not to be selected till all the eye-bars are manufactured. The tests shall be made from time to time as the bars are selected. When three bars have been tested, the bars manufactured up to the time of the selection of these three test bars shall be accepted or rejected as the result of such tests, and the same shall be done again when three more bars are tested. In the tests, the failure of one bar to develop a stretch of 10 per cent before breaking shall be sufficient reason for rejecting the whole lot; but a failure to break in the body of the bar shall not be a sufficient PROPOSALS. Separate proposals should be made for the deck spans (including bents) and the through spans. The price for the deck spans should be a uniform price per pound for all classes of material. Prices for the through spans should be by the pound at separate rates for steel, wrought iron, and cast iron. The prices shall include material, and all patterns and other work of every description, and are to be on the basis of finished material delivered on cars at Chicago ready for shipment to Council Bluffs. Each proposal will be required to state what class of steel it is proposed to use, and what facilities the bidder can furnish for testing full-sized tension members, and the process by which and place where eye-bars will be manufactured. The right is reserved to accept separate proposals for the deck spans and the through spans, to reject all bids, and to award the contract to other than the lowest bidder. GEORGE S. MORISON, Chief Engineer Omaha Bridge. New York, December 1, 1S85. 2 7 APPENDIX F. TESTS OF STEEL EYE-BARS. TESTS ON FULL-SIZED EYE-BARS. Dimensions, — Inches. Results Fracture. Diameters. E pe'?cSn°. n .' Elastic Lbs. per Maximum phorus. Number. Original. After Testing. Reduction Extension. iff Lbsfper Original. 2SS- Nominal. Acuai. Gauged &£ Percent w,» Sft Tlin'.. n-.‘. »«. Thickness. 6 ■A 268.69 6.00 I.062 4.562 O.75 46.30 240 I3-8S 39.560 63.215 Body - - - - - - - S4 E 6 if 268.60 6.00 I.25O 4.500 O.875 47.50 240 15.65 36.400 58,065 “ - - - - - - - 84 E 5 tt 268.63 5.00 O.677 3-937 O.50 51.50 240 14.80 40,320 59.520 “ - - - - - - - 84 E 7 ■I 268.65 7.00 I.36 5-3' O.78 56.30 228 16.OO 36.630 59,980 “ .740 •524 49-87 27.50 43,710 65,430 0.063 5645 7 ■i 26S.65 7.00 I. S 0 - - - 228 - 38,840 46,030 Head .742 •545 46.35 24.75 45,35° 6 S,Soo 0.067 5583 7 ■f 268.65 7.00 1.62 5.22 O.96 55-8° 22s II.80 36,510 60,250 Body •732 .528 47.96 24.50 44,39° 68,230 0.074 5632 7 i* 268.65 7.04 I.48 544 1.00 47.70 22s 15.70 36.010 60,090 " •732 .528 47-96 24.50 44,390 68,230 0.074 5632 7 if 268.63 7.00 I.76 - - - 22s - 37.240 58.430 Head •734 •539 46.07 25-25 46,090 70,150 5634 7 if 268.65 7.05 '■59 549 1.15 43.60 22s II.60 40,390 67,130 Body •737 .546 45.12 24-75 44,650 70,960 - 5654 7 4 360.41 7.02 1.62 545 1.09 47-75 324 10.60 38,560 65,822 •731 -545 44.42 26.00 45,320 70,620 0.075 5663 6 ** 360.41 6.01 i-3 2 4-53 0.80 54-3' 324 16.40 35.480 60,930 •736 .500 53-86 26.00 43,73° 67,460 0.075 5569 7 if 360.41 7.00 1.63 5-83 1.27 35'0 324 II-5° 37,180 62,380 •727 .501 52.64 26.50 43,250 0.062 5656 7 if 26S63 7.00 1.50 6.74 1.42 8.84 240 6.66 37.300 5S.270 •742 ■545 46.35 24-75 45.350 68 ,Soo 0.067 5583 7 if 26S.63 7-°3 i-5« 5.20 0.91 55-4 2 240 13-90 36,51° 60,720 •742 •545 46-35 24.75 45-35° 68,Soo 0.067 5583 7 if 268.63 6.9S i-73 - - - 240 6.30 34,630 Head •739 •545 45.61 25-75 45.370 69,510 0.076 5634 7 if 268.63 7.02 '■75 5- 2 5 1.07 54.26 240 17-3° 36,190 62,920 Body •736 .508 52.36 27-25 44,900 68,980 0.067 5644 7 if 26S.65 6.95 1.50 5.46 ...2 41.30 240 13.00 42,260 73.370 " 42027 7 ■i 268.65 1.22 - - 240 14.30 76,350 “ - - _ - _ 42027 TESTS ON SAMPLE BARS FROM SAME MELTS. 28 APPENDIX G. LETTER TO MR. T. J. POTTER. Thomas J. Potter, Esq., Vice-President Union Pacific K'y., Omaha , Neb. Chicago, III., Nov. 3,1S87. Dear Sir, — I have directed Mr. Duryea to turn over the Omaha Bridge to Mr. Bogue on the 10th; this completing my connection with the work, excepting such work as remains to be done in preparing my final report upon the same. There is a small amount of work which is properly a portion of the construction of the bridge, but which is not yet done. The principal part of this consists in removing the cylinders of old piers. The eight cylinders composing the four piers which come under the through spans of the new bridge have all been cleared out, and the joints disconnected at least five feet below extreme low water. The cylinders of Piers IV. and V. are embedded so deeply in riprap and other surrounding material that it would be difficult to remove them. Probably after a few floods they can be taken out more easily. The cylinders of Pier III. have both been removed, as was supposed ; but it seems that the lower section of one of these cylinders was broken off in the removal, and remains in position. After another season of high water I think a careful examination should be made here; and if anything is found above a safe height, I think there will be no difficulty in overturning it. In Pier II. one cylinder has been thoroughly removed; the other cylinder cannot be removed until the debris around it is washed away; this will probably occur next year, when this cylinder can probably be tipped over and removed. The east approach to the bridge is a trestle 1,000 feet long, taking the place of four spans of the original bridge. The whole of this trestle has been filled with earth to a height above the high water of i88r, the earth embankment being made the full width of the base of a permanent bank. The easterly quarter of this trestle is an old trestle repaired and enlarged ; the remainder is new, but it was all built as a temporary piece of work, it being expected that the whole would be filled before this. In consequence of the action taken by the City of Council Bluffs, and under the direction of Mr. Calloway, this filling was temporarily abandoned. I should recommend that it be done with as little delay as is consistent with economy. The danger of fire in a trestle of this kind is too great a risk to assume. The estimated quantity of earth required to fill this trestle is 150,000 yards, the cost of which, if done with strict economy, might be kept inside of 20 cents; I should, however, pre¬ fer to estimate it at 25 cents. Moreover, as it is likely that some settlement will occur as the filling proceeds, I think the sum appropriated for this filling should not be less than $40,000. Some years ago the construction of a levee above Council Bluffs was begun. This is the only sure way of protecting the low bottom-land between ■ the town and the river from overflow in extreme floods. I have had a survey made of the route on which I think this levee should be extended to the bridge, and its cost would not be large. It seems to me important that it should be built at an early date; and the advantage of it would be so great to the Union Pacific, as the owner of a large portion of the low bottom-land, that your company could with propriety pay at least one half. In connection with this levee it has seemed to me that the shore line of the river in front of the town of Omaha would be rectified to a very good advantage, this rectification being brought about by building a dike from the west shore above the water works, and gradually extending it towards the bridge line, and so reclaiming something like two hundred acres of land which would be very valuable. The work would be a matter of considerable expense, and if done economi¬ cally would occupy two or three years. If the proposed roadway bridge at the foot of Douglas Street is built on the location proposed, it will defeat this scheme; if such bridge is not built I believe this rectification matter to be one of great importance to your company. The carriage roadways are completed and ready for traffic, and the west approach has been paved from the toll-house to the bridge. Outside of the two toll-houses no paving has been done, but the approaches are graded, and are in good condition for use except in very wet weather. The streets are not graded to a connection with these approaches on either side, and it seems to me important that this should be done. The location of the west approach was a compromise location; it connects with the city street a little east of the intersection of Sixth and Leavenworth Streets. The location which I selected would have terminated at the intersection of Seventh and Marcy Streets, at the north end of the large bridge which your company is build¬ ing across Seventh Street; in my judgment this is the true location for this approach, and I believe it would be worth while to have it graded now. The two roadways are adapted to carriage travel and to foot travel; street railway tracks can be laid at any time without difficulty, and the roadways can be adapted to a cable road at small expense whenever it is thought expedient. While the position of these roadways is undoubtedly such that horses unaccustomed to the situation would be frightened by trains, the position of the roadways between two strong fences is such that the frightened horses could do no harm, and after they had been used a short time, the number of horses that would be frightened would be comparatively small. I do not think the danger of driving on these roadways is as great as the danger of driving in one of the New York streets in which an elevated railroad is built. A wooden fence six and a half feet high above the roadway floor, which could be built at any time without difficulty, would shut out the view of trains from horses on the roadways. It may be expedient to build such a fence; but I should prefer to use the bridge first without it, simply making a regulation that no whistle should be blown, and no steam allowed to escape, while trains are on the bridge. It might also be expedient to give notice that at certain hours of the day — say half an hour in the morning, and half an hour in the afternoon — the bridge would be kept free from railroad trains. I should recommend that the roadways be opened for traffic as early as can conveniently be done; and my judgment would be to fix the tolls at about one half the tolls charged on the ferry trains, and that a notice be put up at each toll-house stating that at certain designated times the bridge would be kept clear of trains, and that persons whose horses were unaccustomed to locomotives had better cross at those hours; with such a notice any responsibility for accidents from frightened horses would be thrown upon the owners, and the bridge would be open for horses accustomed to trains at all times. If there are any points on which you desire additional information from me, I shall be very glad to give it. I regret exceedingly that I failed to see you the last time I was in Omaha, and that my arrangements will prevent my visiting Omaha again before spring. Yours truly, GEORGE S. MORISON, Chief Engineer Omaha Bridge. UP. FL NEW OMAHA BRIDGE. Pjjats S- Ettal Su/€ ' f ert^c-o csa_i c/.£yy spaaa <&» HER. NEW OMAHA BRIDGE. P.LA.TE ms s. IfIBKS. rxss a- ■ Side Elevation. PxjJ^TE 4- UP R. NEW OMAHA BRIDGE. Plan. PIER'C W. AWE *4 HER. NEW OMAHA BRIDGE JPla^te Nate!Untied lines show Stage ofThverg Sinhin g perform ed during Uecember 1BBG January £ February IBB7. JDiagr 1 am showmgrate oj -1 progress IN Sinking Caissons W ■$.. A. i® & <°® c==> ®@ ea> . A 1 } /'V' J JL. \ r 1 - u -- 1 -4- i 1A V I | At e . _ 1 < 1 — A | AA 1 / T ■vj J AN1 JARY 1 F EBHUARY ' MARCH" APRIL MAY JUNE JULY AUGUST SEPTEMBER OCTOBER NOVEMBER BECEMBER ; 1 COVERPLATE 26*t 2 WEBPLATES IB’«i 2 SI DEPLATES IO*£ 4 ANGLES 4» *' 2 FLATS 5‘«y 1 COVER PLATE 2 WEBPLATES A ANGLES A"' 4 2 FLATS S'-.V 1 COVERPLATE 2 WEBPLATES ZSIOEPLATES A ANGLES a'.AV Z FUATS 5’xJ 1 COVERPLATE Z 2 WEBPLATES I ZSIOEPLATES I A ANGLES A'«A 2 FLATS 5'xf 1 COVERPLATE 2 WEBPLATES 2 SI DEPLATES A ANGLES A'-A STEEL STEEL 'CHANNELS if] STEEL STEEL AND Melsrs U.P.R. NEW OMAHA BRIDGE THROUGH SPAN 246 FT 2H N C.'to C. END PINS PljATE IP Plate IE. Section through DEFG % . s f c C~LL ■ ■ O.. Hjj.p lift jU 1 sN XX, TJX ----- [fiSSb' m r«s~* r n A J p li ft iJs fm L \ \ " ’ x> i [V AoIXipj 1 - - H— ”o Plate 3 O. UP.R. NEW OMAHA BRIDGE DECK SPAN 120 ”74™ C. TD C. END PINS Elevation. Elevation of Supfdftino Bents. _ Scale_ ‘ M ' T ; 7 I t TbbI. III.' I^eTbts. c/- ZyT UPR. NEW OMAHA BRIDGE DECK SPAN 12 DMA C to C END PINS ° ° ° ° 4 Chois Section Through Center Suppgrtng Bent Plate 22 J Mr S O A L. E= ■jL.s.yk Assumed Loads in Through Span. Head Load 300O per Foot t SS3B3* -par panel per ?rass { Jf / -Live Load BOOO p bt Foot B3S4EL per panel per truss. Total Load 13 ODD per Footl4SSOS p or panel par Iras s. Excessive Load 1 3000 *par Foot 1113a 7*perpanel per Truss. ■S ft, NEW OMAHA BRIDGE STRAIN SHEET. LLate Ed 5\ BOTTOM LATERAL SYSTEM. THROUGH SPAN. Assumed Loads in Deck Span. EeadLoad 4000 jper Font , 03 at to 4BZSO per panel per truss'. jES^S* alboiloTn. Live Load 3000*per Foot SBSOOper panel per Truss. Total Load 1 SOOO per Foot 144730 per panel per Truss. Excessive Load lDOOO*per Foot ISO BBS per panel pertrus DECK SPAN. IlRFL NEW OMAHA BRIDGE Harness for Combination Crane Plate 3 4. Plan Ml.e §.~/he- M T Pront Elevation' . _ TbP-Q f Maaaarip. isa a Side Elevation FbeI . KilamelBrs. PLA.TE 3 E- UP.R. NEW OMAHA BRIDGE Maf of Missouri River at Omaha PkoposED Rectification. . (S\JjL4jvJ