# built-up beam

## Solution to Problem 599 | Spacing of Rivets or Bolts in Built-Up Beams

**Problem 599**

A beam is formed by bolting together two W200 × 100 sections as shown in Fig. P-599. It is used to support a uniformly distributed load of 30 kN/m (including the weight of the beam) on a simply supported span of 10 m. Compute the maximum flexural stress and the pitch between bolts that have a shearing strength of 30 kN.

## Solution to Problem 598 | Spacing of Rivets or Bolts in Built-Up Beams

**Problem 598**

As shown in Fig. P-598, two C380 × 60 channels are riveted together by pairs of 19-mm rivets spaced 200 mm apart along the length of the beam. What maximum vertical shear V can be applied to the section without exceeding the stresses given in Illustrative Problem 591?

## Solution to Problem 597 | Spacing of Rivets or Bolts in Built-Up Beams

**Problem 597**

A plate and angle girder similar to that shown in Fig. 5-32 is fabricated by riveting the short legs of four 125 × 75 × 13 mm angles to a web plate 1000 mm by 10 mm to form a section 1020 mm deep. Cover plates, each 300 mm × 10 mm, are then riveted to the flange angles making the overall height 1040 mm. The moment of inertia of the entire section about the NA is *I* = 4770 × 10^{6} mm^{4}. Using the allowable stresses specified in Illustrative Problem 591, determine the rivet pitch for 22-mm rivets, attaching the angles to the web plate at a section where *V* = 450 kN.

## Solution to Problem 596 | Spacing of Rivets or Bolts in Built-Up Beams

**Problem 596**

Three planks 4 in by 6 in., arranged as shown in Fig. P-596 and secured by bolts spaced 1 ft apart, are used to support a concentrated load P at the center of a simply supported span 12 ft long. If P causes a maximum flexural stress of 1200 psi, determine the bolt diameters, assuming that the shear between the planks is transmitted by friction only. The bolts are tightened to a tension of 20 ksi and the coefficient of friction between the planks is 0.40.

## Solution to Problem 594 | Spacing of Rivets or Bolts in Built-Up Beams

**Problem 594**

A distributed load of *w _{o}* lb/ft is applied over a middle 6 ft of a simply supported span 12 ft long. The beam section is that in Prob. 593, but used here so that the 8-in dimension is vertical. Determine the maximum value of

*w*if

_{o}*f*≤ 1200 psi,

_{b}*f*≤ 120 psi, and the screws have a shear strength of 200 lb and a pitch of 2 in.

_{v}## Solution to Problem 593 | Spacing of Rivets or Bolts in Built-Up Beams

**Problem 593**

A box beam, built up as shown in Fig. P-593, is secured by screws spaced 5 in. apart. The beam supports a concentrated load *P* at the third point of a simply supported span 12 ft long. Determine the maximum value of *P* that will not exceed f_{v} = 120 psi in the beam or a shearing force of 300 lb in the screws. What is the maximum flexural stress in the beam?

## Spacing of Rivets or Bolts in Built-Up Beams

When two or more thin layers of beams are fastened together with a bolt or a rivet so that they act as a unit to gain more strength, it is necessary to design the to size or spacing of these bolts or rivets so that it can carry the shearing force acting between each adjacent layers.

## Solution to Problem 587 | Design for Flexure and Shear

**Problem 587**

A beam carries two concentrated loads P and triangular load of 3P as shown in Fig. P-587. The beam section is the same as that in Fig. P-577 on this page. Determine the safe value of P if f_{b} ≤ 1200 psi and f_{v} ≤ 200 psi.

## Solution to Problem 577 | Horizontal Shearing Stress

**Problem 577**

A plywood beam is built up of 1/4-in. strips separated by blocks as shown in Fig. P-577. What shearing force V will cause a maximum shearing stress of 200 psi?