CIV4508 STRUCTURAL DESIGN :
School of Engineering University of Southern Queensland
CIV4508 STRUCTURAL DESIGN II ASSIGNMENT 2 (Design 2)
Weighting: 25% (250 marks out of 1000)
Due date: 12 May 2023
In this assignment, you need to demonstrate your understanding of concepts of load path and load estimation, analysis, and design of a steel structure, i.e. a portal framed building. The assignment is based on modules 1, 2, 7-9 and 11. Follow the instructions at the end of the assignment while preparing your assignment.
CIV4508 STRUCTURAL DESIGN Project Brief
A new industrial building is to be constructed as shown on the attached drawings, Figs. 1 and 2. The North direction is shown in Fig. 2. The building will be made of structural steel pitched portal frames. All the joints of the portal frame are rigid connections. The connections between the columns and the footings are bolted (can be assumed as pinned). The sidewalls and the roofs of the building are covered with metal sheeting. The metal sheeting sits on purlins on roof and sits on girts on side walls. The roof sheeting will be fixed to steel purlins running along the length of the building. Purlins (choose Z15024 from Table) @ 1200 mm spacing will be attached to the top flange of the roof beams/rafters and hence, would provide lateral restraint to the top flange of these beams. Similarly, girts (having the same section and spacing as those of purlins) attached to the outer flange of columns would provide lateral restraint to columns.
There are typical glazed windows (L = 2500 mm, H = 1000 mm, 20 mm thick) between grids A- B, C-D and E-F along grid 1 and on alternate bays (B-C, D-E and F-G) along grid 2. Assume that the windows will be centrally placed between 2 adjacent grid lines. There is one roller shutter of 1220 mm wide and 2200 mm high along grid A, and another one (with the same dimension) is along grid 1 between D and E. There is a door of dimensions 1000 mm x 2100 mm is on grid 2 between C and D. The floor is made of reinforced concrete.
The building is to be located in region B, a non-cyclonic region. The ultimate design wind speed at the location has been estimated as 60 m/s and is the same in all directions. Similarly, the serviceability design wind speed has been estimated as 40 m/s and is the same in all directions. Assume that lateral bracing systems along grids 1 and 2 that would carry the wind loading in the longitudinal direction. You do not need to design the bracing system and ignore them while calculating the self-weight. Also ignore the self weight of the bracing systems on the two end panels and on the roof for prelim calculations. Because of the bracing system in place, the columns have pinned connections at the top in the longitudinal direction. Assume that on both 1 & 2 grids, there is a beam at the eaves level (assume any section) connected between the 1st- 2nd column at the top and then another one is between 2nd-3rd column and so on till the end column. These beams provide lateral restraint to columns and also form part of the bracing system. On the other hand, the portal frames will carry the wind loading in the transverse direction. Take appropriate values of the parameters X, Y, Z as appropriate from Table 1 depending on the last two digits of your Student ID number. Assume appropriate realistic values for other design data that are not provided.
- Use appropriate standards (AS1170.0 2002, AS1170.1 2002 and AS1170.2 2021) for the estimation of loads and AS4100 2020 using One Steel of Grade 300 for steel design.
- Use linear elastic analysis and limit state design.
- Ignore secondary effects.
2. STRUCTURAL Problem statement
Q1. Load estimation (50 marks)
- Calculate the loads (Dead Load +Live Load) acting on a typical portal frame. (10 marks)
- Calculate the wind loads acting on a typical portal frame (refer Fig. 2) for the Easterly wind direction.
- Determine Cshp and design pressures for the external surfaces: windward, leeward, sidewalls and roof, assuming Ka = 1. Draw the pressure diagrams with clear labels. (10 marks)
- Determine Cshp and design pressures for the internal surfaces. (10 marks)
- Determine the worst uplift load for the roof and the worst loading cases for the columns due to the wind loading. (20 marks)
Q2. Analyse a typical portal frame using Strand7 (50 marks)
Analyse the portal frame on Grid C for appropriate loading combinations for strength and serviceability considerations using Strand7.
- Display the frame with the boundary conditions first (5 marks).
- Plot the BMD (15 marks), SFD (10 marks) and AFDs (10 marks) and, deflected shapes (10 marks) of the frame for each loading combination.
Plot at least 2 diagrams (example, BMD, SFD) in 1 page without affecting the readability. No need to show the plots for individual loadings, say, DL (G). Present a table of the design loads and moments for RC1 and C1, to be designed in Questions 3 and 4.
Q3. Roof Beam/Rafter design (50 Marks)
Design a typical roof beam RC1 on Grid C for strength (40 marks) and serviceability (10 marks) requirements. Use One Steel 300 grade Universal Beam sections.
Q4. Column design (50 Marks)
Design a typical column C1 on Grid C for strength (40 marks) and serviceability (10 marks) requirements. Use One Steel 300 grade Universal Beam sections.
Q5. Connection design (50 Marks)
Design a bolted connection between the roof beam RC1 and column C1, shown in Fig. 1 below in circle (40 marks). It is a rigid bolted connection that would transfer the forces and BMs to columns. To simplify the problem, no haunch will be provided at the joints that means rafters will have prismatic sections. You can assume that there are end-plates welded to the rafter at both ends. Welding design is not required, assume that the welded connection is safe. Draw the connection detailing (10 marks).
Fig. 1. A typical portal frame of the building on Grid C
Fig. 2. Layout plan of the building.
Table 1: Design Data
|Student ID number (last two digits)||X (mm)||Y (mm)||Z (mm)|
Note the following:
Please submit a xxx.pdf file electronically using the submission link under ‘Assignment 2’ of the Assessment tab. No other means of submission is permitted. The file will be named in the following format: Surname_First Name_student number_Assignment 2.pdf.
The assignment would contain one set of safe design for all structural elements showing all the necessary steps and all your trial designs should go in the Appendix in proper sequence. Marks will be given for systematic design with comments.
If you are using worksheet (Excel type) for iterative design calculations, once your design is finalised, you need to show that set of safe design calculations clearly. Work sheets will not be marked.
Mention all the relevant clauses of the code at the left/right margin throughout the design so that they can be checked.
If you use incorrect parameters, you can lose up to 20% of the total marks of the assignment.