Tham khảo tài liệu 'structural steel designers handbook part 10', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | DESIGN CRITERIA FOR BRIDGES TABLE Basic Allowable Stresses for Railroad Bridges0 Continued Loading condition Allowable stress psi 4 where Fv allowable shear stress reduced due to combined stress psi Sa allowable shear stress when loaded in shear only psi ft average tensile stress due to direct load psi A4 nominal bolt area in2 T4 minimum tension of installed bolts lb Bearing on expansion rollers and rockers lb per lin in for diameters up to 25 in for diameters from 25 in to 125 in where d diameter of roller or rocker in Fy yield point of steel in roller or base whichever is less Fy - 13 000 Fy - 13 000 600d 3000Vd a For steel castings allowable stresses in compression and bearing are same as those of structural steel of the same yield point. Other allowable stresses are 75 of those of structural steel of the same yield point. 4 For bearing on expansion rollers and rockers values are expressed as lb per lin in. Note 1 The expression 1 - LI r 2 Fy 1 800 000 is applicable only for members with solid rectangular flanges and for standard I-shaped beams. Note 2 Applicable for surfaces with clean mill scale free of oil paint lacquer or other coatings and loose oxide for standard size holes as specified in AREMA Manual Art. . Where the Engineer has specified special treatment of surfaces or other than standard holes in a slip-criical connection the allowable stresses in AREMA Commentary Table may be used if approved by the Engineer. Note 3 For single bolt in line of force or connected materials with long slotted holes Fu is the limit. A value of allowable bearing pressure Fp on the connected material at a bolt greater than permitted can be justified provided deformation around the bolt hole is not a design consideration and adequate pitch and end distance L are provided according to Fp LFuI2d . Source Adapted from AREMA Manual American Engineering and Maintenance-of-Way Association 8201 Corporate Drive Suite 1125 Landover
