3-Bearing Type Connections- Part 2.

Last Updated on September 17, 2026 by Maged kamel

Bearing Type connections-part-2.

Summary of the Post content.

The nominal tensile strength for a Bolt Rn.

In this Post, bearing type connections-part-2. Le is the edge distance from the Bolt centerline to the edge.

We are concerned with the distance behind theBoltt (Le-d/2), where Le is the distance from the Cg of the external Bolt to the adjacent edge. At the same Time, d is (the diameter of the bolt+1/16″).

The clear distance is called lc outer Lco, which is the distance from the edge of the external Bolt to the edge of the plate. This is the section of the two connected plates on the following slide.

Rn is the nominal bearing force due to a tension force applied on the left; Rn is the sum of the two forces on each side of lines 1-1 and 2-2 and can be estimated as 2*0.6Fu*Lco*tp, since the Shear strength is taken as 0.60Fu. The length of each side equals lco, and the height of the plate equals t.

If the surrounding material is weak, the Bolt will be stronger than the surrounding material because it tears the Shear plane. What will happen? Two forces resist the tear-out; their sum equals 1.2*Fu*tpl*Lo, where Lo is the clear distance from the edge of the Bolt.

We will examine the inner distance between two bolts. The nominal force R is split into R/2 and R/2. The Shear strength of the plate material = lc*t*0.60 Fu.

Re is the lower limit if lc is less than 2d.

The upper limit is achieved when lc = 2d—the nominal resistance equals 2*0.60*Fu*2d*t*2 = 2.4*Fu*t*Lco.

AISC equations for bearing connections.

For the next slide, a series of equations: Rn = 1.20*Lc*t*Fu.< or =2.40*d*t*Fu, if deformation around Bolt holes is a design consideration and the deformation is less than or equal to 0.25 inches. The Value of (1.20*Lc*t*Fu) is reached when lc is less than 2dh.

The upper limit Value of (2.40*d*t*Fu) is reached when lc equals 2dh.
But if the deformation i 25 inches and is not a design consideration,nthenn Rn.50*Fu*Lc*t <= 3.0*d*t. Another condition applies to long slotted holes.

In the next slide, refer to the definitions. The distance between the centerlines of bolts in the direction parallel to the axis of the member is the pitch P. S is the gage distance, the distance between the centerlines of bolts in the direction perpendicular to the axis of the member, and the edge distance.

Minimum edge distance of bolts: Tables J3.4 and J3.4M.

On the next slide, the minimum edge distance varies with both diameters and follows Table J3.4. The metric version of the same table, J3.4M, is also included.

If we have a Bolt diameter of 3/4 inch, the minimum edge distance is equal to 1 inch. For the metric dimension, a Bolt with a diameter of 20mm will have a minimum edge distance of 20mm, as shown in Table J3.4M.

The minimum external for oversized or slotted holes equals le plus c2, where c2 is obtained from Table J3.5.

Minimum Spacing S and the inner distance between bolts.

In the post-Bearing Type connections, Part 2. The minimum spacing between bolts is S.
The minimum center-to-center distance is not less than (2 2/3 db), where db is the Bolt diameter. Preferably, it should be 3d, or 3 diameters. But the clear distance should be at least d.
Minimum center-to-center should be not less than 2  2/3 diameters.

The following slide image shows the different types of holes. Use oversized holes in slip-critical connections, while short slotted holes can be used for slip-critical and snug-tight connections. The long slotted holes can be used for slip-critical and snug-tight connections.

Nominal Hole dimension for bearing-type connection.

For the Hole diameter, add 1/16″ to the Bolt diameter; unlike in tension members, we were adding (1/16″+1/16″) to theBoltt diameter for the calculations. For instance, for a 3/4 ” diameter Bolt add 1/16″; then the standard dia will be  (3/4+1/16)=13/16″  as shown in table J3.3. The table gives the different Hole dimensions as four standard oversized short and long slots. The next slide shows a sketch of the various Hole types.

The nominal strength of fasteners.

The next slide shows the Shear strength values in Table J3.2.
The tensile strength, written as Fnt, is in the second column. The nominal Shear strength symbol, Fnv, is in the third column and is expressed as a percentage of Fnt.

For instance. In the first column, there is a description of the type of fasteners (A307, Group A, A325-N), which are not excluded; the tensile strength Fnt = 90 ksi; and Fnv = 0.60*90 = 54 ksi. The Value shown in brackets is the MMP Value. ForA325-X, Fnt=90 ksi. Fnv=68 ksi. For X, the Shear strength increases. There are categories: b) ASTM-A490 bolts N&X, with the corresponding Fnt and Fnv values shown.

The Shear strength increased for X. Category b) shows ASTM-A490 bolts N&X with the corresponding Fnt and Fnv values.

The following Table J3.5 and J3.5M show the required values for C2.

The last slide image is quoted from the specification for the maximum spacing and edge distance. The maximum spacing from any Bolt to the nearest edge shall not be more than 12 times the thickness of the connected part but shall not exceed 6 inches.

This is the PDF file used for this post; you can view or download it using the button below.

For part 1- bearing-type connection- part-1, this is the Link.
The next Post, 4 covers nominal Shear strength and bearing tear-out, made simple.

This is a very useful source for designing various Steel elements: A Beginner’s Guide to the Steel Construction Manual, 15^th ed. Chapter 4 – Bolted Connections.

This is a very useful source for designing various Steel elements: A Beginner’s Guide to the Steel Construction Manual, 16^th ed., Chapter 4 – Bolted Connections.