Steel structure

The two-bay portal frame shown can be subjected to either of the following load systems:

OA horizontal load of 2W at B and a vertical load of 3W at the centre of span CD

(b) A horizontal load of 2W at B and a vertical load of 3W at the centre of spanВС.

If the plastic moment of the beams is 1.5 Mp and that of the columns M, calculate the minimum value of W which would cause collapse of the structure.Sketch the bending moment diagram of the structure at collapse indicating significant values.

Steel structure

.The shaft shown in the figure is machined from AISI 1040 CD steel. The shaft rotates at 1600rpm and is supported in rolling bearings at A and B. The applied forces are F1 = 2500 Ibf andF2 = 1000 lbf. Determine the minimum fatigue factor of safety based on achieving infinite life.If infinite life is not predicted, estimate the number of cycles to failure. Also check for yielding.

Steel structure

2. For the interval 10 3 <N< 10° cycles, develop an expression for the axial fatigue strength (S'fJaxial for the polished specimens of 4130 used to obtain the figure below. The ultimate strength is Sut = 125 kpsi and the endurance limit is (S'e)axial = 50 kpsi.

Steel structure

1. A steel rotating-beam test specimen has an ultimate strength of 230 kpsi. Estimate the fatigue strength corresponding to a life of 150*103 cycles of stress reversal.

Steel structure

2. Describe the stages of fatigue failure

Steel structure

1. Define fatigue strength and endurance limit

Steel structure

The preferred material specification for W-shapes is

О с. А625

d. A992

O a. A500

b. A365

e. А100

Steel structure

What is the LRFD design yielding limit strength (kips)for a HSS 4x4x3/8 for A500 Gr. B?

O a. 249 kips

O b. 57.9 kips

e. 198 kips

O c. 196 kips

d. 73.3 kips

Steel structure

An office in the city is subject to dead loading of 50psf and a live loading of 70 psf. Determine the maximum load combination in "psf" assuming no roof, snow, wind, seismic, and nominal loading (psf:pounds per square foot) from the equations given below:

С. 45

O d. 70

O b. 120

O a. 172

О е. 130

Steel structure

What is the effective net area (in2) of a gusset plate with a total thickness of 0.75 inches used for Tension that has ten bolted holes given a GrossArea of 30 in² and a nominal bolt diameter of 0.125inches. The given pitch "s" is =0.35 inches and the gage "g" is = 0.15 inches