design of temporary structures multi part homework

HANGING SCAFFOLD – USE THE INFORMATION BELOW TO SOLVE THE FOLLOWING PROBLEMS.

This problem is based on the hanging scaffold in Figure 1, with two working decks. Assume medium duty loading. There are two outrigger beams and they are A36 steel, 20 ft long and are as shown in the sketch below. In addition to the live load, include in your calculations, a total scaffold dead load (weight of the cables, scaffold and scaffold hoists) of 1400 lbs. The scaffold length is 40 feet and the width is 4 feet. ONE of the outrigger beams will support half of these dimensions.

1. Determine the minimum breaking strength of the suspension cables, based on OSHA requirements.
2. Using your scaffold load, draw a neat free body, shear and moment diagrams of one of the outrigger beams. Determine all the values of all shear forces and moments. Make sure they are neatly displayed on the diagrams. Identify with boxed the value of the Vmax and Mmax.
3. Replace the scaffold load in Part b, with 7.5 kips and determine the minimum weight (yd3) and the minimum size (ft) of the counterweight, based on OSHA requirements. Assume the geometric shape of the counterweight to be a cube.
4. Ignore the answer in Part b, using a maximum bending moment of 100,000 lb-ft, select the most economical wide flange beam using the tables in Appendix 1 for the outrigger beams. Be sure the beam you select is stable, i.e. the depth should not be more than 1.25 times the flange width. Show all calculations in the PDF submittal.

Determine the live load on the scaffold in lbs.

Determine the minimum breaking strength of the suspension cables, based on OSHA requirements. Answer in lbs.

Using your scaffold load, draw a neat free body, shear and moment diagrams of one of the outrigger beams. Include in PDF calculation submission. Determine all the values of all shear forces and moments. Make sure they are neatly displayed on the diagrams. Identify the value of the Vmax = kips and Mmax = .kip-ft

HINT: Don’t include the directions of the V and M in the answer. Only the magnitude is required! Also make sure to keep rounding to two decimal places.

Replace the scaffold load in Part b, with 7.5 kips and determine the minimum counterweight load = lbs, minimum volume = (yd3) and the minimum size = (ft) of the counterweight, based on OSHA requirements. Assume the geometric shape of the counterweight to be a cube.

THIS PROBLEM STATEMENT APPLIES TO THE PROBLEMS THAT FOLLOW.

Ignore the answer in Part b, using a maximum bending moment of 100,000 lb-ft, select the most economical wide flange beam using the tables in Appendix 1 for the outrigger beams. Be sure the beam you select is stable, i.e. the depth should not be more than 1.25 times the flange width. Show all calculations in the PDF submittal.

Calculate the section modulus. Answer in in^3.

Select the most economical wide flange beam. Be sure the beam you select is stable, i.e. the depth should not be more than 1.25 times the flange width. Show all calculations in the PDF submittal.

Hint: First ensure that it meet and/or exceeds the strength criteria (S), then depth/width ratio <1.25, finally most economical section (least material/weight).