Design Project

To understand the basic approach in the analysis and design by using STAADpro
Project Description:
Modeling:
The project will involve doing the following mandatory procedures:
Create a model of a seven-story steel frame building in STAAD Pro. The plan of building has a regular beam and column arrangement through 7 stories. Story heights are as follows – first two stories are 15 ft, next 2 stories are 12 ft and the top 3 stories are 10 ft. The small squares indicate column locations. The columns are identified by the lines A – F and 1 – 6. Thus the column shown shaded would be identified as column C-1 and shaded area between C3, D3, C4 and D4 is open area.
Modeling structure includes: (nodes, beams and columns) using STAAD pro; input all primary load cases and LRFD load combinations. Analyze the structure and prepare table of member forces in frame members. All members of the frame – Beams and Columns – are W-sections
Service Loads:
The floor service loads are:
Dead Load (representing 4-inch concrete slab)
45 psf
Live Load (reducible as per ASCE7)
80 psf
The roof service loads are:
Dead Load (representing 3-inch roof slab)
35 psf
Live Load
15 psf (ROOF LIVE LOAD)
Snow Load
23 psf
Rain Load
17 psf
The wind profile is approximated by a lateral pressure of 10 psf up to a height of 10 ft, 18 psf from 10 ft to 20 ft, 24 psf from 20 ft to 35 ft, 28 psf from 35 to 50 ft and 32 psf upward from 50 ft.
The beams and columns are fabricated from A992 steel (Fy = 50 ksi; Fu = 65 ksi) and the floor slabs are 4-inch-thick reinforced concrete slabs (fc’ = 3500 psi). THERE IS NO NEED TO INCORPORATE THE CONCRETE SLABS INTO THE MODEL.
Load Cases:
Dead load (include self-weight)
Roof Live Load
Snow Load
Rain Load
Live Load
North-South Wind (W1)
East-West Wind (W2)
Load Combinations:
1.4D
1.2D 1.6L 0.5Lr
1.2D 1.6L 0.5S
1.2D 1.6L 0.5R
1.2D 1.6Lr 0.5L
1.2D 1.6Lr 0.5W1
1.2D 1.6Lr 0.5W2
1.2D 1.6S 0.5 L
1.2D 1.6S 0.5 W1
1.2D 1.6S 0.5 W2
1.2D 1.6R 0.5 L
1.2D 1.6R 0.5 W1
1.2D 1.6R 0.5 W2
1.2D 1.0 W1 0.5 L 0.5Lr
1.2D 1.0 W1 0.5 L 0.5S
1.2D 1.0 W1 0.5 L 0.5R
1.2D 1.0 W2 0.5 L 0.5Lr
1.2D 1.0 W2 0.5 L 0.5S
1.2D 1.0 W2 0.5 L 0.5R
1.2D 1.0 E 0.5 L 0.2S
0.9D 1.0 W1
0.9D 1.0 W2
0.9D 1.0 E
Analysis:
Perform steel (LRFD) design using STAAD Pro. Use the following sequence:
Perform analysis
Select all members
Perform analysis
Select members
3.Group members. Group all beams from first 4 floors into one group (LOWERBEAMS) and all beams from 5th – 7th floors into one group (UPPERBEAMS). Similarly group all columns from first 4 floors into one group (LOWERCOLUMNS) and all columns from 5th – 7th floors into one group (UPPERCOLUMNS).
The final design iteration performed by STAAD will indicate that for each group, the size selection was done based on a particular member (the one with the worst loading). Thus, there will be 4 such members noted – one for each group. Using the interaction equations in Chapter H of the AISC Manual, verify the results indicated by STAAD, using results from the final analysis. YOU NEED TO SHOW THIS
DETAILED RESULTS VERIFICATION (4 DIFFERENT MEMBERS) FOR THE MOMENT FRAME ONLY.
SINCE THE STEEL GRADE IS A992, YOU WILL BE ABLE TO GET VALUES SUCH AS Lp, Lr, φbMp etc. FROM THE STEEL MANUAL (for Fy = 50 ksi). I ALSO WANT YOU TO DEVELOP A SPREADSHEET TO DO THESE CALCULATIONS IN CASE THE STEEL GRADE IS CHANGED TO 36 ksi (say).
Investigate 2 options:
Model the frame as a moment frame. Show detailed calculations.
2. Model the frame as a braced frame (choose diagonal bracing in corner bays). Use HSS shapes as brace members. Release the moments at both ends of only the bracing members. Adding braces will increase the total number of member.
Comment on the final design for both options. Compare the final outcome of the two designs using typical indicators such as chosen sizes for the various groups, maximum lateral drift (for the wind case) etc. Also, have STAAD-Pro do a quantity take off for each case.
Assessment Metrics:
You will be evaluated based on the following criteria:
Technical merit
oIntroduction and project objectives o Approach to the Project Description o Analysis of results
o Summary and/or conclusions
o References cited where necessary Creativity and innovation
Instructor’s evaluation