## 1609

The column flange can be checked for bending (prying) in the same way, but since the flange thickness tf = 1.720 in > 1, the flange is satisfactory.

Weld A. This weld (Fig. 5.65a) has a length of about 10 in and the load it must carry is

PA = VH2 + VC2 = V89.92 + 64.62 = 111 kips The weld size required in sixteenths of an inch is

A V4-in fillet weld is sufficient, but the minimum fillet weld permitted by the AISC specifications for structural steel buildings for 1-in-thick steel is 5/16 in (unless low-hydrogen electrodes are used). Use a 5/16-in weld.

Gusset to Beam. Weld B (Fig. 5.65a) is 32 in long and carries a load

This weld is a flare bevel-groove weld that attaches plate B to the top corners of the beam (Fig. 5.66). Satisfying ASTM tube specification A500, this shape has a radius R = 3i, where t = tube thickness = 3/8 in nominal (Fig. 5.65c). The AISC specifications assume that R = 2t. Use of this radius to compute weld throat te (Fig. 5.66) is conservative for the following reason: The design strength of the flare groove weld, when it is made with E70 electrodes, is given by the product of te and the weld length and the design stress, 31.5 ksi. The AWS defines te as 5/16R when the groove is filled flush (Fig. 5.66).

With R = 2t, te = 2 x 0.375 x 5/16 = 0.234 in. The throat required is

Thus use a flush flare bevel-groove weld.

Experience shows that tube corner radii vary significantly from producer to producer, so verify in the shop with a radius gage that the tube radius is 2 x 0.375 = 0.75 in. If R < 0.75, verify that S/16R > (0.095 in = V8 in). If 5/16R < V8 in, supplement the flare groove weld with a fillet weld (Fig. 5.67) to obtain an effective throat of V8 in.

Plate B. This plate is used to transfer the vertical load VB = 67.4 kips from the "soft" center of the tube top wall to the stiff side walls of the tube. For determination of thickness tB, plate B can be treated as a simply supported beam subjected to a midspan concentrated load from the gusset plate (Fig. 5.68). The bending moment in the beam is 67.4 x %. =

FIGURE 5.66 Effective throat of a flare bevel- FIGURE 5.67 Fillet weld reinforces a flare bevel-groove weld. groove weld.

135 in-kips. The plastic section modulus is 32tB2/4. The design strength in bending for the plate is 0.9Fy = 0.9 X 36 = 32.4 ksi. Substitution in the flexure equation (f = M/Z) yields

from which tB = 0.72 in. This indicates that a 3/4-in-thick plate will suffice. As a check of this 32-in-long plate for shear, the stress is computed:

## Renewable Energy 101

Renewable energy is energy that is generated from sunlight, rain, tides, geothermal heat and wind. These sources are naturally and constantly replenished, which is why they are deemed as renewable. The usage of renewable energy sources is very important when considering the sustainability of the existing energy usage of the world. While there is currently an abundance of non-renewable energy sources, such as nuclear fuels, these energy sources are depleting. In addition to being a non-renewable supply, the non-renewable energy sources release emissions into the air, which has an adverse effect on the environment.

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