4. Number of sidewalks required. 5. Width of sidewalks... 6. Type of bridge preferred-steel, concrete, or wood. 8. Give date and elevation of average low water. 9. Is the crossing on a "trunk" or secondary road. 10. If grade has been established show elevations on profile. 12. Condition of road from railroad station to bridge-site. 13. Can sand and stone for concrete be obtained locally. If so, give distance from bridge-site.. 14. Can timber for falsework and piling be obtained locally. If so, give distance from bridge-site. 15. Is there a bridge at this site at present. If so, indicate location on map and profile. 16. Will it be necessary to maintain traffic during construction of new bridge... 17. Is design of approaches desired. . . . . . . 18. If earth-filled approaches prove economical, is suitable material available for filling. 19. Will the approaches be constructed by county forces.. 20. Give date of desired completion of structure.. 21. Give direction in which roads will approach bridge... 22. Note if there will be plenty of clearance for swinging teams in narrow canyons or bluff surroundings.. BRIDGE PLANS.-The plans for a bridge must contain all the information necessary for the design of the structure, for ordering the material, for fabricating the bridge in the shop, for erecting the structure, and for making a complete estimate of the material used in the structure. Every complete set of plans for a bridge must contain the following information, in so far as the different items apply to the particular structure. 1. General Plan.—This will include a profile of the ground; location of the structure; elevations of ruling points in the structure; clearances; grades; direction of flow, high water, and low water; and all other data necessary for designing the substructure and superstructure. 2. Stress Diagram.—This will give the main dimensions of the bridge, the loading, stresses in all members for the dead loads, live loads, wind loads, etc., itemized separately; the total maximum stresses and minimum stresses; sizes of members; typical sections of all built members showing arrangement of material, and all information necessary for the detailing of the various parts of the structure. 3. Shop Drawings.-Shop detail drawings should be made for all steel and iron work and detail drawings of all timber, masonry and concrete work. 4. Foundation or Masonry Plan.-The foundation or masonry plan should contain detail drawings of all foundations, walls, piers, etc., that support the structure. The plans should show the loads on the foundations; the depths of footings; the spacing of piles where used; the proportions for the concrete; the quality of masonry and mortar; the allowable bearing on the soil; and all data necessary for accurately locating and constructing the foundations. 5. Erection Diagram. The erection diagram should show the relative location of every part of the structure; shipping marks for the various members; all main dimensions; number of pieces in a member; packing of pins; size and grip of pins, and any special feature or information that may assist the erector in the field. The approximate weight of heavy pieces will materially assist he erector in designing his falsework and derricks. 6. Falsework Plans. For ordinary structures it is not common to prepare falsework plans in the office, this important detail being left to the erector in the field. Erection plans should be worked out in the office, and should show in detail all members and connections of the falsework, and also give instructions for the successive steps in carrying out the work. Falsework plans are especially important for concrete and masonry arches and other concrete structures, and for forms for all walls, piers, etc. Detail plans of travelers, derricks, etc., should also be furnished the erector. 7. Bills of Material.-Complete bills of material showing the different parts of the structure with its mark, and the shipping weight should be prepared. This is necessary in checking up the material to see that it has all been shipped or received, and to check the shipping weight. 8. Rivet List.-The rivet list should show the dimensions and number of all field rivets, field bolts, spikes, etc., used in the erection of the structure. 9. List of Drawings.-A list should be made showing the contents of all drawings belonging to the structure. DESIGN PLANS.—The preliminary plans of steel bridges may consist (1) of a stress diagram showing the stresses, dimensions and sizes of the principal members of the bridge, and also standard specifications as given in Appendix I; (2) of detail plans which show the make-up of all the members together with the maximum and minimum spacing of the rivets, thickness and sizes of plates, lacing bars, etc., and also standard specifications; and (3) of completely detailed shop plans and specifications. When properly carried out all of the methods will give satisfactory results. Ordinarily the customer cannot understand the details of the bridge from a study of the stress diagram and finds the second and third methods much more satisfactory. It is seldom profitable to prepare shop plans until after the order for the bridge has been placed in the shop, and requisitions have been made for the material. On the whole, the method of preparing the preliminary plans, as described in (2), is the most satisfactory. This makes it possible to specify exactly the details of the sections and at the same time permits the bridge shop to follow its own methods wherever possible. The shop practice in different shops differs so much that it is ordinarily cheaper for the bridge company to prepare its own shop plans than to follow shop plans that have been prepared by engineers that are not familiar with the particular shop. The plans for concrete bridges should be prepared as shown in Chapters XIX to XXIII, inclusive, and specifications as in Appendix II. BRIDGE CONTRACTS.-The contracts for building highway bridges are ordinarily let by county commissioners, county surveyors or other county officers. In a few states contracts for building bridges are let by state or highway engineers. The common method of awarding contracts for highway bridges has been about as follows: Three or four weeks before the date set for the bridge letting the county clerk or other officer advertises that bids will be received up to a certain hour for building a certain bridge or bridges, and that the bids will then be publicly opened and the contract awarded. The main dimensions and the capacity only are ordinarily specified and the bidders are asked to submit their own plans and specifications. When the various bids and plans are received the commissioners are entirely at a loss as to what is the best thing to do, and the result is that either the contract is given to the lowest bidder on a very poor plan or is given to a favorite bidder on a plan that results in a worse bridge. This loose method of contracting for bridges makes it practically impossible for even honest officials to procure a satisfactory structure and opens up the way for dishonest officials and contractors to arrange a deal whereby the public comes out second best. It also makes it possible for the contractors to "pool" so that the bridge contract will go to a member of the pool at an agreed price. The county surveyor or local engineer is ordinarily not much better posted on the merits of the bids and plans than the commissioners, and his participation in the letting does not ordinarily improve matters. The practice of "bridge pooling" is disreputable and has worked to the disadvantage of both the public and of reputable bridge companies. It has made it possible for "fake bridge companies" to exist and also for crooked public officials to receive part of the profits of the transaction. It has uniformly resulted in high prices and poor bridges. Before advertising for bids the matter of the design of the bridge or bridges should be placed in the hands of a competent consulting bridge engineer. Detail plans and specifications should be prepared and an estimate of the probable cost submitted to the officials. All bids should then be received on the official plans and specifications. If the bids are too high they should all be rejected and the work readvertised on the same or on revised plans. The bridge contractor takes a considerable risk and is entitled to a good legitimate profit, and the engineer should add 15 to 20 per cent for profit to his estimated cost. No work should be done at the shop until after the shop plans have been checked and approved by the consulting engineer. The shop, field and final inspection should be in the hands of the consulting engineer. This method will meet the approval of all legitimate bridge companies, and will result in better bridges at a less cost. In several states the construction of highway bridges is supervised by the state highway commission, while in other states the state highway commission gives assistance in preparing plans and constructing highway bridges when requested so to do. ADVERTISEMENT FOR BIDS.-To obtain bids from responsible bidders the bridge letting should be advertised in the local papers and in the technical press. The following advertisement will serve to show what data should be furnished prospective bidders. BRIDGE ADVERTISEMENT. KEWANEE, ILLINOIS. Sealed proposals will be received by the Board of Commissioners of Road Improvement District No. 1, of Henry County, Illinois, at Kewanee, Illinois, until eleven o'clock A.M., Aug. 7, 1919, for the construction of bridges and culverts as follows: Proposals must be submitted on the form furnished by the Board and must be accompanied by a certified check, payable to the Treasurer of Road Improvement District No. 1, Henry County, Illinois, for not less than five per cent of the total amount of the bid. Plans, specifications and estimate of quantities may be examined at the office of the Consulting Engineer, Kewanee, Ill., and at the office of the Board of Commissioners of Road Improvement District No. 1, Kewanee, Illinois. Plans will be furnished by the undersigned upon receipt of deposit of five ($5) dollars which will be refunded upon safe return of plans. The right is reserved to reject any or all bids and to waive any informality in the bids received. BOARD OF COMMISSIONERS OF ROAD IMPROVEMENT DISTRICT NO. 1, HENRY COUNTY, ILLINOIS. JOHN C. JONES, Consulting Engineer. CONTRACT. After the contract has been awarded the contract papers should be drawn up and signed, and an indemnity bond should be furnished by a good surety company. contract and bond forms used by the author follow: Sample Witnesseth, that for the consideration and upon the terms and conditions hereinafter provided, the party of the first part agrees to furnish all material and labor therefor, and construct and erect in a good and workmanlike manner .over the County of ..... according to the attached plans and speci ........ spans; extreme fications which are made a part of this contract: The bridge is to have .... It is further agreed that the said first party shall save and hold said second party free and harmless from any and all claims for damages to life, limb or property occasioned or caused by said first party's employees; and from all claims for materials and labor furnished on this contract. The party of the first part agrees to complete the work herein contracted for, and to have the said bridge open and ready for travel on or before the day of 19..... ........ The party of the second part agrees to pay the party of the first part for said bridge the sum of in cash, as follows: per cent upon the delivery by the party of the first part of the steel and other material on the bridge site for said bridge, per cent additional upon the completion of the erection of the different parts of the bridge, and the remaining ........ per cent upon the completion and acceptance of the bridge by the consulting engineer of the second party. Estimates of material delivered and work done shall be made by the consulting engineer not later than the 5th day of the month for all material delivered or work done during the preceding month, and the payment will be made on or before the 15th of the month for the material delivered and work done the preceding month. It is further stipulated and agreed that the party of the first part shall furnish to the party of the second part an indemnity bond in an approved surety company in the sum of ............. ... dollars. It is further stipulated and agreed that for the failure of the first party to complete the bridge as stipulated the said first party shall forfeit dollars for each working day until the bridge is completed. This sum to be considered as liquidated damages, and not as a penalty. (It is further stipulated and agreed that the party of the first part shall not be held responsible for delays in delivery of material from the rolling mills, nor delays in transportation, nor for delays occasioned by strikes, fires, floods, storms, or other circumstances beyond its control, but may be granted an extension of time as may be determined by the consulting engineer of the second party.) In Witness Whereof, the said parties to this agreement hereunto set their hands and seals as of the day and year first above written. BOND. First Party. Know all Men by These Presents, that first part, and the ..... as party of the a corporation organized and existing under the as Surety, are held and firmly bound unto the ... party of the second part, its successors and assigns, in the sum of .... laws of the State of ..... dollars, lawful money of the United States, to the payment of which sum well and truly to be made the said first party and the said Surety do hereby bind themselves, their heirs, executors, administrators, successors and assigns, jointly and severally, firmly by these presents. day of ., 19..... Signed, Sealed, Dated and Delivered, this which contract is hereto attached and made a part hereof, and for a fuller description thereof reference is made to said contract: NOW, THEREFORE, THE CONDITION OF THIS OBLIGATION IS SUCH, that if the said party of the first part shall and does pay as they become due, all just claims for all work and labor performed and all skill and material furnished in the execution of such contract, and, also, shall save the party of the second part named in this bond harmless from any cost, charge and expense that may accrue on account of the doing of the work specified in such contract according to the terms thereof and the contract price therein, and shall comply with all the requirements of the law, then this obligation shall be void; otherwise to remain in full force and effect. IN TESTIMONY WHEREOF, We have hereunto set our hands and seals, this day of...... Signed, sealed and delivered in the presence of ...., 19..... to me known, who, being by me duly sworn, did depose and say that he resided in ; that he is the ... ..... of the ..... the corporation described in and which executed the above bond as party of the first part; that he knew the seal of said corporation; that the seal affixed to said instrument was such corporate seal; that it was so affixed by order of the board of directors of said corporation and that he signed his name thereto by like order. 2 and for the County and State aforesaid, personally came to me known, who, being by me duly sworn, did depose and say that he resided in ; that he is the of the ... the corporation described in and which executed the above bond as Surety; that he knew the seal of said corporation; that the seal affixed to said instrument was such corporate seal; that it was so affixed by order of the board of directors of said corporation and that he signed his name thereto by like order. Notary Public. |