SEISMIC DESIGN (CONCRETE)


In this page is reported the final design of a six-story reinforced concrete structure. This residential dwelling is located in Cittareale (RI-Italy).
According to the NTC08 (Italian Building Regulation) and INGV (Natianal Institute of Vulcanology and Seismology) provisions the buiding is assigned to Seismic Zone 1.
A plan and elevation of the building are shown. The lateral-load-resisting system consist of moment resisting frames in both orthogonal direction. There are five bays in the N-S direction and four bays (with two external 4 meter long cantilever balconies) in the E-W direction. The tipical story height is 3 meter.
The structural model imported in SAP 2000 is the one showed in the above image. The behaviuor of the structure was investigated using a variety of models and analytical techniques.
The structure was initially proportionated using a preliminary analysis (Linear Static and Dynamic Analysis), the succeeding analysis show that the structure falls short of several performance expectations. In attempt to improve performance the dimension of structural element was improved. The design of steel reinforcement was due to improve the ductility of the structure. To apply the performance-based design the strong-column-weak-beam design concept was adopted. The design of steel reinforcement of the floor, the beam and the column are here plotted. The beam in both orthogonal direction have the same design of reinforcement. For the columns is plotted the steel reinforcement design of one column as example.
Different model were done to compare different behaviour of the structure under seismic load. This model were done to quantify the influence of the foundation, the lift and the stairs. When all the performance expectation match with the provvision of italian regulation a Nonlinear Static (pushover) 3D Analysis was performed to ensure the ductility capacity. To perform that kind of analysis was required the definition of the plastic hinges whose model is defined in the FEMA provvision.
In the capacity spectrum method, the pushover curve is transformed to a capacity curve that represents the first mode inelastic response of the full structure. Then the capacity and the domain of ductility were compared. The Pushover Analysis results are here plotted.
Complete calculation report.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s