Assignment on Seismic Design
You have been commissioned to carry out a preliminary design of a 5-storey reinforced concrete building (non-storage) located on a rock site (Class B) in Melbourne for the 1,000 year return period event (Importance Level 3).
The building measures 20 m x 20 m in plan and is 15 m tall above the raft foundation. Each story has equal height. The lateral force resisting system consists of moment- resisting concrete frames which have ordinary detailing consistent with AS3600.
The centre of mass is offset from the centre of stiffness by 2 m in plan in each direction. Assume the combined dead load and superimposed dead load is 8 kPa for each floor. Imposed load is 4 kPa for typical floors and 1 kPa for the roof.
Determine the earthquake design category (EDC) and calculate the following in accordance with AS1170.4 (2007):
- Base shear force and lateral force distribution (considering 100% seismic action in one direction only). Noted that a fraction of the imposed action has to be taken into account.
- Distribution of bending moment with height assuming the lift shaft walls behave as vertical cantilever members.
- Torsional moment at the foundation level (considering 100% seismic action in one direction only).
- Approximate distribution of earthquake floor accelerations at each level.
- The forces acting on a piece of equipment of weight Wc = 3 kN using Sections 8.2 assuming the equipment is ductile, non-critical and is rigidly fixed to the building at roof level.
Please make clear references to AS1170.4 for any values and equations that you use in the calculation process.