APPENDIX No. 2. GUN AND MORTAR BATTERIES, SAN FRANCISCO HARBOR, CALIFORNIA. REPORT OF COL. GEORGE H. MENDELL, CORPS OF ENGINEERS, OFFICER IN CHARGE, FOR THE FISCAL YEAR ENDING JUNE 30, 1893. Gun batteries. IMPROVEMENTS. b Mortar battery. UNITED STATES ENGINEER OFFICE, San Francisco, Cal., August 7, 1893. GENERAL: I have the honor to transmit herewith annual reports for the year ending June 30, 1893, as follows: Gun and mortar batteries, San Francisco Harbor, California. The work is completed as far as can be done until details of the carriages to be used are received. The masonry of Emplacement 16 was completed; all the masonry of emplacements 14 and 15 laid; the earth protection, front and rear, on six emplacements was made; the roadway in rear was excavated, macadamized, and drained; floors of asphaltum, at 12 cents per square foot, and of sidewalk concrete at 93 cents per square foot, were laid in the six emplacements, the asphaltum in Emplacements 11 and 12, and the concrete in Emplacements 13, 14, 15, and 16; all masonary was plastered within and without, at 3 cents per square foot; doors were made and hung; slopes carefully dressed and sown with oats and barley and manured. There remains to be done when mounting is known 1,107 cubic yards of concrete to be laid in gaps in breastwalls; construction of terrepleins; 33,676 square feet of bituminous rock covering 3 inches thick, and 3,168 square feet of same 6 inches thick, to be laid over masonry; elevating machinery for Emplacements 14, 15, and 16, and overhead travelers for the six emplacements. There is also 110 feet of roadway to be finished, the making of which was obstructed by a cement shed built across the proposed line; this shed has been removed and the roadway will soon be completed. A concrete plant purchased in 1891-92 was used for mixing concrete. It consisted of one 50 H. P. boiler, one 35 H. P. Westinghouse Junior engine, one Gates No. 3 rock-crusher, one Ransome and Smith No. 3 concrete-mixer, and one Stearn's bucket elevator. The materials were dumped into hoppers feeding to the mixer, which automatically combines them in proper proportions, mixes them in a revolving churn, and delivers to boot of elevator, which raises them 32 feet to a hopper over the cars on a tramway above the top of masonry. This plant was run with occasional interruptions from July 1 to October 13. During this time 7,409 cubic yards was mixed and laid on Emplacements 14, 15, 16 (2,703 on Emplacement 16, and 4,706 on Emplacements 14-15). The plans for Emplacements 14 and 15 were changed by placing the magazines of both in a single mass of masonry between the terrepleins of both, with 6 feet interval between adjacent rooms of each. In giving quantities by emplacements in the report Emplacements 14 and 15 are treated as a single emplacement. In addition to above concrete, 1,876 cubic yards was mixed by hand and 1,257 cubic yards of concrete from old magazines and breast walls was imbedded in the new; also 6 cubic yards of large rock was imbedded in the concrete, making total masonry for the year 10,548 cubic yards. This total was distributed over the emplacements as follows: Ninety-one cubic yards on Emplacement 11; 6 cubic yards on Emplacement 13; 7,032 cubic yards on Emplacements 14, 15, and 3,418 on Emplacement 16. Concrete was made in proportions of 1 cement, 3 sand, and 8 rock; gravel was sometimes used and counted as rock when large and clean. The rock used was quarried at Angel Island, San Francisco Harbor, and delivered at wharf at 89 cents per 2,000 pounds. Gravel was ob tained from Gravelly Beach and Horse-shoe Bend, Lime Point reservation, and delivered at wharf at 90 cents per cubic yard. The sand was obtained from Fort Point Beach and from the Presidio Beach; the latter was delivered at wharf at 50 cents per 2,000 pounds. The materials were hauled to the concrete plant by contract at the following prices: Rock Gravel Cement Sand from beach or wharf Raising sand to sea wall from beach Cents. The cement used was Josson & Co.'s Portland cement, furnished at $2 per barrel over ship's side, and lightered to wharf by A. C. Freese at 15 cents per barrel. This gives cost of materials at plant as follows: Rock, $1.28 per 2,000 pounds, or $1.73 per cubic yard (including 9 cents per ton for receiving at wharf). Gravel, $1 per 2,000 pounds, or $1.30 per cubic yard. Sand from Fort Point Beach, 544 cents per 2,000 pounds. The water used in concrete was fresh, and pumped to a reservoir whence it is drawn to the plant. The pumping was effected by a Dow steam pump, purchased in 1891-292, with a capacity of 1,000 gallons per hour. The earthwork during the year consisted mainly of filling in the slopes front and rear on the six emplacements and in excavating the roadway in rear. All of the excavated material was used in filling, and in addition, a large amount mainly loam was borrowed from the ground in rear of emplacements. The excavation amounted to 10,004 cubic yards, and was done at a cost of about 43 cents per cubic yard. The earth fill amounted to 19,922 cubic yards, and was done at a cost of about 33 cents per cubic yard. The sand fill required in plans in front of masonry was made partially of sand from Fort Point Beach and partially of a loamy sand hauled from dunes in rear of the works. It amounted to 4,712 cubic yards, and was done at a cost of 32% cents per cubic yard. The greater cost of earth fill is due to expense of dressing and the planting slopes. The outlay during the year was as follows: Concrete (10,547 cubic yards) Excavation (10,004 cubie yards). Fill (23,946 cubic yards) Plastering and flooring. Drainage and water supply Macadam and gutters on roads, doors, ladders and steps Incidentals: Office and post-office box rent, pay of overseer, timekeeper, draftsman, and messenger, etc.. Total...... $35, 876.85 4,304.60 7,992.67 1, 883. 08 858.37 3, 302. 10 11, 278. 18 65, 495.85 Giving the concrete its proper proportion of incidental expenses ($7,462.38), adding $17,264.26 for cement on hand June 30, 1892, and subtracting $5,500 for cement on hand at completion of work, the cost of 10,547 cubic yards of concrete is $55,103.49, or $5.22 per cubic yard. The average cost per cubic yard of all concrete laid on works from beginning to end is $5.78. 2 B. MORTAR BATTERY No. 1. This battery is of the adopted type of 16-mortar battery for 12-inch breech-loading rifled mortars. Ground was broken for this battery on April 5, 1893, and work has been in progress on it ever since. The excavation was effected by plowing and scraping on the shallow portions and by blasting on the deeper ones. The excavation for the rooms and passages was completed June 20, and the excavation then ceased until concrete should be laid on this portion. The excavation during this time amounted to 10,781 cubic yards. The concrete plant was moved to a position west of the battery, repaired and set up at a cost of $2,469, including tramway over excavation. The concrete plant was run from June 21 to June 30, inclusive, and during this time 507 cubic yards was mixed and laid; 21 cubic yards of hand-mixed concrete was also laid, making a total of 5283 cubic yards. At the end of the year the excavated portion was covered with concrete 1 foot thick. Allowing the concrete its proper proportion of expenses on plant, it was laid at a cost of $4.18 per cubic yard. The rock for concrete was obtained from a quarry on the Fort Point Beach and delivered at the plant by contract at $1.03 per 2,000 pounds. The sand was obtained from Fort Point Beach and delivered at plant at 30 cents per 2,000 pounds. The cement was Josson's Portland, and cost at plant $2.21 per barrel. The water is fresh and derived from same source as for gun battery. The drainage is complete over portion excavated, consisting of a 10inch main drain, with 6-inch drains to pits and 3-inch drains around outside of masonry. A conduit for electric-firing wires was laid in the floor. Concrete (5284 cubic yards). Excavation (10,781 cubic yards). Drainage.. Electric-wire conduit Incidentals. Total....... Allowing excavation its share of incidentals, $714.17, the 10,781 cubic yards is $4,533.27, or 42 cents per cubic yard. $9,028.69 3, 819. 10 1, 174.98 321.75 4, 125.59 18, 470. 11 cost of |