CVE20003, Design of Concrete Structures

CVE20003, Design of Concrete Structures

Project 1 – Analysis of a multistorey concrete building

A multi story building is to be designed and constructed in Melbourne’s eastern suburbs. A preliminary assessment by the engineer has nominated that a concrete framed building would be most suitable. The engineer has nominated the geometry of the structure as per figures 1 and 2 below. 

The beams and columns will be rigidly connected using steel reinforcement and should be designed as a moment resisting frame to resist the horizontal forces which will be imposed on the structure due to wind actions (Wu) in the locations shown in figure 1. The columns are fully fixed into footings at their base and footing to column connection can be assumed as rigid for design purposes. All column dimensions should be taken as 500mm x 500mm square in cross section. 

Each level is to be designed for retail loads (shopping areas, classification D in AS1170.1 table 3.1) using respective dead and live loads extracted from AS1170.1. After analysis by the engineer, dead load (DL) including finishes is to be taken as 15 kN/m and the live load (LL) should be taken as 40 kN/m. A wind loading analysis conducted by the engineer has determined that a constant positive wind load of (Wu) of 50 kN at each level. 

Figure 2 – Section A-A

Prior to the design of the structural members, an analysis is required to determine the critical design actions such as bending moments, shear forces and axial forces in all members of the frame.

The self weight of the RC floor system should be considered in addidtion to dead and live loads given above. The gravity loads should include self weight of the beams, slabs and columns.

As the cadet engineer on the project, you are requried to perform the following tasks:

1. Based on AS1170.0, the designer has determined that two load combinations for ultimate limit state should be used to determine the critical design actions on the structure for later use in design:

E_d1 = [1.2G, W_u, 0.4Q] and E_d2 = [1.2G, 1.5Q]

Using the unfactored design actions provided, determine the factored design actions applied to the frame. [5 marks]

2. Using the portal method, determine the factored bending moments, shear forces and axial loads for the frame. The bending moments, shear forces and axial loads should be determined independently using both load combinations for [E_d1 & E_d2] specified in part 1. Note that to determine the moments and forces using load combination E_d1, the moments, shear forces and axial loads due to wind loads and gravity loads will need to be determined separately and combined using the principal of superposition. [60 marks]
3. Using Space Gass, determine the factored bending moments, shear forces and axial loads for the frame using both load combinations [E_d1 & E_d2]. [20marks]
4. Compare the column reactions, maximum and minimum bending moments, shear forces and axial loads obtained from the portal method and spacegass. Use tables to discuss any differences in accuracy between these methods. Note that the comparison only needs to be made at the maximum and minimum moment/shear force locations at the worst story/locations. [10 marks]
5. The final project report must be a concise, organized, and easy-to-read document. The exact layout and table of contents of the final design project report is up to the individual. The report should have enough information to assess the accuracy and the approach used for the analysis and appropriate outputs from spacegass and hand calculations illustrating the results. [5 marks]