Design for Lateral Loads/Systems
336868 - Performance-Based Seismic Evaluation of a Reinforced Concrete Industrial Building Under a 10,000-year Earthquake Event
Friday, April 20
11:00 AM - 12:30 PM
A reinforced concrete industrial building is required to be designed in accordance with ACI 318-14 code requirements and ASCE 7-10 seismic loads. The building is located at a high seismic zone and near earthquake fault lines. Due to the manned building having important function and equipment, the plant owner requests to perform a seismic design evaluation of the building for a 10,000-year return period (0.5% @ 50 years) earthquake event. Therefore, a probabilistic seismic hazard assessment (PSHA) at plant site was carried out for the 10,000-year event in addition to the maximum considerable earthquake (MCE) of 2475-year period (2%/50 years) per ASCE 7-10 requirement. The provisions of ACI 318 are intended to provide Life Safety (LS) structural performance under ASCE design basis earthquake (DBE) which is two-thirds of the “risk-targeted” Maximum Considered Earthquake (MCER). The equivalent return period of DBE event is 475 years (10%/50 years). From PSHA study, the peak horizontal spectral response accelerations for the 10,000-year event, MCER and DBE are 2.3g, 1.8g and 1.0g, respectively. The corresponding vertical response spectra are determined to be the same as the horizontal response spectra.
For ordinary structures, life safety under a DBE hazard event are ensured by designing the structure for the effects of code-prescribed earthquake forces and by conforming to material design and detailing requirement set forth in the code. In this study, building is designed for DBE seismic loads first and then carry out a performance-based seismic evaluation of the building to assure adequate capacity of preventing collapse from a MCER event. An assessment the damage levels of building components under the 10000-years earthquake event is then carried out. Required strengthening of the structural components to prevent the building from collapse under the extreme event is recommended to plant owner for considerations of structural upgrade. The Linear Dynamic Procedure (LDP) in ASCE 41-13 is adopted for the seismic performance evaluation in this study since the building height is low and has no irregularity in the structure layout. It does not require a tedious nonlinear dynamic analysis which is still under research and development. From the study, it is concluded that the linear dynamic procedure is a practical and efficient approach for strengthening a building to minimize the structural damages from an extreme earthquake event which beyond the code prescribed minimum design loads. The analysis and design approaches presented in this study can also be effectively used to retrofit existing industrial buildings.