allowing owner and contractor to share, in an agreed-on ratio, the cost savings achieved by the contractor, or to reward the contractor for completing the project ahead of schedule. Evaluation of bids by an owner may take into consideration the experience and reputation of the contractor, as a result of which awards may not be made on a strictly low-bid basis. Budget Estimate. Often, an owner in preparing plans and specifications will want to determine the expected construction cost while the plans are still in a preliminary stage. The owner, in that case, will ask contractors for a cost estimate for budget purposes. If the estimate from a specific contractor appears to be satisfactory to an owner, and if the owner is desirous of establishing a contractual relationship with the contractor early in the planning stage so as to benefit from the contractors suggestions and guidance, a contract may be entered into after the submission of the estimate. On the other hand, the owner may refrain from formally entering into the contract, but may treat the contractor as the favored contractor. When requested, this contractor will assist the architect and engineers with advice and cost estimates and will expect to receive the contract for construction on completion of plans and specifications, if the cost of the project will lie within the budget estimate when plans and specifications have been completed. Separate Prime Contracts. Sometimes an owner has the capability for managing construction projects and will take on some of the attributes of a general contractor. One method for an owner to do this is to negotiate and award separate prime contracts to the various trades required for a project. Administration of these trades will be done either by the owners own organization or by a construction manager hired by the owner (Art. 17.9). Sale Lease-Back. This is a method used by some owners and government agencies to obtain a constructed project. Prospective builders are asked to bid not only on cost of construction, but also on supplying a completed building and leasing it to the prospective user for a specified time. This type of bid requires a knowledge of real estate analysis and financing, as well as construction. Contractors who bid may have to associate with a real estate firm to prepare such a bid. Developer/Sponsor-Builder. In this type of arrangement (Art. 17.1), the contractor may not only have to prepare a construction-cost estimate but may also need a knowledge of real estate and be prepared to act as owner of the completed project, in accordance with the terms of a sponsor-builder agreement with a government agency, or government-assisted neighborhood or nonprofit group. The following types of contracts are used for general construction work: Letter of Intent. This is used where a quick start is necessary and where there is not sufficient time for drafting a more detailed contract. A letter of intent also may be used where an owner wishes material ordered before the general contract is started, or where the commitment of subcontractors requiring extensive lead time must be secured immediately. Lump-Sum Contract. (For example, Document A-101, American Institute of Architects, 1735 New York Ave., N.W. Washington, D.C. 20006.) Basis of payment is a stipulated sum. Progress payments, however, are made during the course of

In regions of positive moment, the total horizontal shear Vh, kips, to be carried by the shear connectors between the point of maximum moment and the point of zero moment is the smallest value computed from Eqs. (7.73) to (7.75). V  0.85 A (7.73) h cc V  A F (7.74) h s y V  Q (7.75) h n where  c 28-day compressive strength of concrete, ksi Ac  area of concrete slab within the effective width, in2 As  area of the cross section, in2, of steel beam Fy  specified minimum yield stress of the steel Qn  sum of the nominal strengths, kips, of the shear connectors between the point of maximum moment and the point of zero moment The number of shear connectors n must equal or exceed Vh /Qn, where Qn is the nominal strength of one shear connector. The nominal strength, kips, of one stud shear connector embedded in a solid concrete slab is Q  0.5A
E  A F (7.76) n sc cc scu where Asc  cross-sectional area of a stud shear connector, in2  c 28-day compressive strength of concrete, ksi Fu  minimum specified tensile strength of a stud shear connector, ksi Ec  modulus of elasticity of the concrete, ksi The nominal strength, kips, of one channel shear connector embedded in a solid

Type MI. Mineral-insulated cable sheathed in a watertight and gastight metallic tube. Cable is completely incombustible and can be used in many hazardous locations and underground. MI cable can also be fire-rated, making it acceptable as a fire-pump feeder. Type MC. One or more insulated conductors, sheathed in an interlocking metal tape or a close-fitting, impervious tube. With lead sheath or other impervious jacket, Type MC may be used in wet locations. Type AC. (Also known as BX cable.) This has an armor of flexible metal tape with an internal copper bonding strip in close contact with the outside tape for its entire length. This provides a grounding means at outlet boxes, fixtures, or other equipment. Type AC cable may be used only in dry locations. Type ACL. In addition to insulation and covering as for Type AC, Type ACL has lead-covered conductors. This makes this type suitable for wet or buried locations. Type ACT. Only the individual conductors have a moisture-resistant fibrous covering. Type NM or NMC. Nonmetallic-sheathed cables (also known as Romex). This type may be used in partly protected areas. The New York City Code permits BX (Type AC) but does not allow Romex because it is not rodentproof and is subject to nail damage in partitions. Type SE or USE. Service-entrance cable has a moisture-resistant, fire-resistant insulation with a braid over the armor for protection against atmospheric corrosion. Type USE is the same as Type SE, except that USE has a lead covering for underground uses. Type UF. This type is factory assembled in a sheath resistant to flames, moisture, fungus, and corrosion, suitable for direct burial in the earth. The assembly may include an uninsulated grounding conductor. Cables may be buried under 18 in of earth or 12 in of earth and a 2-in concrete slab. 15.6.4 Nonmetallic Extensions Two insulated conductors within a nonmetallic jacket or extruded thermoplastic cover may be used for surface extensions on walls or ceilings or as overhead cable with a supporting steel cable made part of the assembly. Extensions may be used in dry locations within residences or offices. Aerial cables may be used only for industrial purposes. At least 10 ft should be provided above the floor as clearance for pedestrians only, 14 ft for vehicular traffic. 15.6.5 Cable Bus and Busways Busways are bar conductors of rectangular cross section, which are assembled in a sheet-metal trough. The conductors are insulated from the enclosure and each other. Busways must be exposed for heat dissipation. They are arranged with access openings for plug-in and trolley connections. For heavy current loads, such as services, several insulated cables may be mounted in parallel, at least one diameter apart, within a ventilated metal enclosure with access facilities. Cable bus costs less than bus bars for the same load but generally takes up more space. Use is limited to dry locations. 15.6.6 Electrical Connections A variety of devices are commercially available for connecting two or more wires. One type, a pressure connector, called a wire nut, may be screwed over two or three wires twisted together. Another type consists of end lugs attached to wires by squeezing them together under great pressure with a special tool. The lugs have a flat extension with a bolt hole for connection by bolts to a switch or busway. As an alternative, two wires may be joined together in a similar manner with a barrelshaped