【正文】 section area of the flange plate. When high strength bolts are used for the split joint of profile steel elements, steel plates may be used as the elements. Shim plates shall be added on the slope surface of the profile steel. For the friction surface of high strength bolting, protective measures need to be taken when it is laid up for a long time. When the high strength bolting is pleted, antirust paint shall be applied in accordance with the coating requirements. Paint is used to seal the bolt and the surrounding area of the joint. For high strength bolting, the operable spaces for dedicated construction machines shall be considered in the course of the design (figure ). Refer to Table for the minimum dimensions. When a value is less than that in Table , long socket wrench may be used to tighten the bolt, the diameter of the socket head is generally the size of the nut’s cross line plus 10mm, but the b value needs to have sufficient length. Table Dimensions of operable spaces Type of wrench Minimum size (mm) a b Manual wrench with set torque moment 45 140+c Electric wrench of torsion shear type 65 530+c Heavy hexagonal electric wrench 60 Chapter III Construction and Acceptance Section I Transportation and Conservation of High Strength Bolt Sets High strength bolt set of heavy hexagonal type consists of one heavy hexagonal bolt, one nut and two washers. The assembly of all parts shall be in accordance with Table . High strength bolt set of torsion shear type consists of one bolt, one nut and one washer. High strength bolt set shall be applied with the same lot. Table Combination of high strength bolt set of heavy hexagonal type Bolt Nut Washer 10H HRC3545 8H HRC3545 High strength bolt set of each plete lot shall be provided by the manufacturer, with the quality certificate available. In the course of transportation and conservation of high strength bolt sets, the high strength bolt set shall be loaded and unloaded with great care so as not to damage the thread. High strength bolt sets shall be categorized and stored according to the lot number and specification marked on the package. They shall be stored indoors and should not be stacked too high to avoid rust and contamination. The package of high strength bolt sets must not be opened at will before installation. When high strength bolt sets are to be installed at site, they shall be withdrawn from the warehouse according to the quantity needed that day. The remaining high strength bolts from that day must be stored carefully. During installation, the thread s。 n quantity of high strength bolts on one side of the web plate’s split joint When the connection length 1l on one end of the structure’s node or on one end of the split joint is larger than 15d0 in the direction of forcebearing, the bearing capacity of the high strength bolt shall multiply the reduction coefficient (0 dl? )。 bN according to the stipulations of section . The high strength bolt on the web plate is calculated according to equation () or (—2) under the condition of N=0, M=M2。 1I the inertia moment of the flange against the gross section of the girder’s central axis。 nquantity of high strength bolt on the side of the flange split joint。 ethe horizontal distance between the center of the bolt group and the center of the split joint. When 11/xy 3, the equation (—1) may be simplified to the following equation: bNnVyMynNN ???????????????? ?? ? 222111 (—2) The bN in equations (—1) and (—2) is the design load of one high strength bolt. For the friction type, equation () is adopted. For pressure bearing connection, the lower of the design bearing capacity as calculated from equation (—1) and (—2) is adopted. The split joint of the whole section of Ibeam (figure ) may be calculated either in the way that the bending moment is assumed by both the flange and the web plate or in the way that the bending moment is assumed by the flange and the shear force is assumed by the web plate. When the calculation is made in the way that the bending moment is assumed by the flange and the web plate, the shear force that the high strength bolt on the flange is bearing may be calculated according to the following equations: bf NhnMN ??? 11 () where fN1 the shear force that each high strength bolt bears on the flange split joint。 iiyx, the horizontal and vertical distances from the center of the bolt group to the No. i bolt on the split joint。 M, N, Vthe bending moment, axial and shear force that the split joint is bearing。 iy distance from the No. i bolt of each bolt line to the central axis of the bolting group。 1a coefficient, when the load is on the upper flange, and the web plate of the girder is planed smoothly to press the upper flange, 1a =, for other situation, 1a =。 1a supporting length of the concentrated load on the span direction of the girder, for the crane girder, 50mm may be adopted。 ? coefficient, for heavy crane girder, ? =, for other girder, ? =。 Vshear force of the girder’s calculated section。 aspacing of high strength bolts on the flange。 ?t the lower total thickness of the pressure bearing element in the same force bearing direction。 d nominal diameter of the bolt。 f design value of tensile or pact strength of the element steel.. The shearresistant friction type connection under the repeated dynamic loads may be not subject to the fatigue calculation, but the base metal at the connection shall be subject to the fatigue calculation in pliance with the ―Code for design of steel structure‖ (GBJ17). Section III Calculation of Pressurebearing Connections For the pressurebearing