6.5. Rivet Shear Strength

Although the actual state of stress in a riveted joint is complex, it is customary to ignore such considerations as stress concentration at the edge of rivet holes, unequal division o£ load among fasteners, and nonuniform distribution of shear stress across the section of the rivet and of the bearing Stress between rivet and plate. Simplifying Assumptions are made, which are summarized as follows:

(1) The applied load is assumed to be transmitted entirely by the rivets, friction between the connected plates being ignored.

(2) When the center of cross-sectional area of each of the rivets is on the line of action of the load, or when the centroid of the total rivet area is on this line, the rivets of the joint are assumed to carry equal parts of the load if of the same size; and to be loaded proportionally to their section areas otherwise.

(3) The shear Stress is assumed to be uniformly distributed across the rivet section.

(4) The bearing Stress between plate and rivet is assumed to be uniformly distributed over an area equal to the rivet diameter

(5) The stress in a tension member is assumed to be uniformly distributed over the net area.

(6) The stress in a compression member is assumed to be uniformly distributed over the gross area.

The design of riveted joints based on these assumptions is the accepted practice, although none of them is strictly correct.

The possibility of secondary failure due to secondary causes, such as the shearing or tearing out of a plate between rivet and edge of plate or between adjacent rivets, the bending or insufficient upsetting of long rivets, or tensile failure along a zigzag line when rivets are staggered, are guarded against in standard specifications by provisions Is summarized as follows:

  • The distance from a rivet to a sheared edge shall not be less than 1 3/4 diameters, or to a planed or rolled edge, 1 ½ diameters.
  • The minimum Rivet spacing shall be 3 diameters.
  • The maximum rivet pitch in the direction of stress shall be 7 diameters, and at the ends of a compression member it shall be 4 diameters for a distance equal to 1 1/2 times the width of the member.
  • In the case of a diagonal or zigzag chain of holes extending across a part, the net width of the part shall be obtained by deducting from the gross width the sum of the diameters of all the holes in the chain, and adding, for each gauge space in the chain, the quantity S2/4g, where S = longitudinal spacing of any two successive holes in the chain and g _ the spacing transverse to the direction of stress of the same two holes. The critical net section of the part is obtained from that chain which gives the least net width.
  • The shear and bearing stresses shall be calculated on the basis of the nominal rivet diameter, the tensile stresses on the hole diameter.

If the rivets of a joint are so arranged that the line of action of the load does not pass through the centroid of the rivet areas then the effect of eccentricity must be taken into account.

6.5. Rivet Shear Strength

Although the actual state of stress in a riveted joint is complex, it is customary to ignore such considerations as stress concentration at the edge of rivet holes, unequal division o£ load among fasteners, and nonuniform distribution of shear stress across the section of the rivet and of the bearing Stress between rivet and plate. Simplifying Assumptions are made, which are summarized as follows:

(1) The applied load is assumed to be transmitted entirely by the rivets, friction between the connected plates being ignored.

(2) When the center of cross-sectional area of each of the rivets is on the line of action of the load, or when the centroid of the total rivet area is on this line, the rivets of the joint are assumed to carry equal parts of the load if of the same size; and to be loaded proportionally to their section areas otherwise.

(3) The shear Stress is assumed to be uniformly distributed across the rivet section.

(4) The bearing Stress between plate and rivet is assumed to be uniformly distributed over an area equal to the rivet diameter

(5) The stress in a tension member is assumed to be uniformly distributed over the net area.

(6) The stress in a compression member is assumed to be uniformly distributed over the gross area.

The design of riveted joints based on these assumptions is the accepted practice, although none of them is strictly correct.

The possibility of secondary failure due to secondary causes, such as the shearing or tearing out of a plate between rivet and edge of plate or between adjacent rivets, the bending or insufficient upsetting of long rivets, or tensile failure along a zigzag line when rivets are staggered, are guarded against in standard specifications by provisions Is summarized as follows:

  • The distance from a rivet to a sheared edge shall not be less than 1 3/4 diameters, or to a planed or rolled edge, 1 ½ diameters.
  • The minimum Rivet spacing shall be 3 diameters.
  • The maximum rivet pitch in the direction of stress shall be 7 diameters, and at the ends of a compression member it shall be 4 diameters for a distance equal to 1 1/2 times the width of the member.
  • In the case of a diagonal or zigzag chain of holes extending across a part, the net width of the part shall be obtained by deducting from the gross width the sum of the diameters of all the holes in the chain, and adding, for each gauge space in the chain, the quantity S2/4g, where S = longitudinal spacing of any two successive holes in the chain and g _ the spacing transverse to the direction of stress of the same two holes. The critical net section of the part is obtained from that chain which gives the least net width.
  • The shear and bearing stresses shall be calculated on the basis of the nominal rivet diameter, the tensile stresses on the hole diameter.

If the rivets of a joint are so arranged that the line of action of the load does not pass through the centroid of the rivet areas then the effect of eccentricity must be taken into account.