scholarly journals Application of Mode-Adaptive Bidirectional Pushover Analysis to an Irregular Reinforced Concrete Building Retrofitted via Base Isolation

2021 ◽  
Author(s):  
Kenji Fujii ◽  
Takumi Masuda
Keyword(s):  
Reinforced Concrete ◽  
Base Isolation ◽  
Pushover Analysis ◽  
Half Cycle ◽  
2016 Kumamoto Earthquake ◽  
Isolation Technique ◽  
Reinforced Concrete Building ◽  
Kumamoto Earthquake ◽  
The 2016 Kumamoto Earthquake ◽  
Concrete Building

In this article, the main building of the former Uto City Hall, which was severely damaged in the 2016 Kumamoto earthquake, is investigated as a case study for the retrofitting of an irregular Reinforced Concrete building using the base-isolation technique. Its peak response is predicted via mode-adaptive bidirectional pushover analysis (MABPA), which was originally proposed by the authors. In the prediction step of MABPA, the peaks of the first and second modal responses are predicted considering the energy balance during a half cycle of the structural response. The numerical analysis results show that the peak relative displacement can be properly predicted by MABPA. The results also show that the performance of the retrofitted building models is satisfactory for the ground motion considered in this study, including the recorded motions in the 2016 Kumamoto earthquake.

scholarly journals Application of Mode-Adaptive Bidirectional Pushover Analysis to an Irregular Reinforced Concrete Building Retrofitted via Base Isolation

2021 ◽  
Vol 11 (21) ◽  
pp. 9829
Author(s):  
Kenji Fujii ◽  
Takumi Masuda
Keyword(s):  
Reinforced Concrete ◽  
Base Isolation ◽  
Pushover Analysis ◽  
Half Cycle ◽  
2016 Kumamoto Earthquake ◽  
Isolation Technique ◽  
Reinforced Concrete Building ◽  
Kumamoto Earthquake ◽  
The 2016 Kumamoto Earthquake ◽  
Concrete Building

In this article, the applicability of mode-adaptive bidirectional pushover analysis (MABPA) to base-isolated irregular buildings was evaluated. The point of the updated MABPA is that the peaks of the first and second modal responses are predicted considering the energy balance during a half cycle of the structural response. In the numerical examples, the main building of the former Uto City Hall, which was severely damaged in the 2016 Kumamoto earthquake, was investigated as a case study for the retrofitting of an irregular reinforced concrete building using the base-isolation technique. The comparisons between the predicted peak response by MABPA and nonlinear time-history analysis results showed that the peak relative displacement can be properly predicted by MABPA. The results also showed that the performance of the retrofitted building models was satisfactory for the ground motion considered in this study, including the recorded motions in the 2016 Kumamoto earthquake.

scholarly journals Pushover-Based Seismic Capacity Evaluation of Uto City Hall Damaged by the 2016 Kumamoto Earthquake

Buildings ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 140 ◽  
Author(s):  
Kenji Fujii
Keyword(s):  
Pushover Analysis ◽  
Nonlinear Behavior ◽  
Equivalent Linearization ◽  
2016 Kumamoto Earthquake ◽  
Seismic Capacity ◽  
Limit Values ◽  
Kumamoto Earthquake ◽  
City Hall ◽  
The 2016 Kumamoto Earthquake ◽  
Capacity Index

The seismic capacity of the main Uto City Hall building, which was severely damaged by the 2016 Kumamoto Earthquake, was evaluated by the proposed pushover-based procedure. In this procedure, the seismic capacity index of the building is defined as the maximum scaling factor of the seismic input, for which the local responses do not exceed their limit values. From the pushover analysis result, the displacement limit of the equivalent single-degree-of-freedom model was determined. Then, the seismic capacity index was evaluated using an equivalent linearization technique. The evaluated index was re-evaluated by considering the bidirectional excitation. The pushover analysis result revealed that the torsional response is significant in the nonlinear behavior of this building. The evaluated seismic capacity implied that some structural damages, including the yielding of the beam-column joint, may have occurred during the first earthquake on 14 April 2016.

scholarly journals Perbandingan Perilaku Struktur Gedung Beton Bertulang dengan Pelat Lantai Beton Konvensional dan Pelat Lantai Kalsi

2019 ◽  
Vol 24 (2) ◽  
pp. 176
Author(s):  
Ni Kadek Astariani ◽  
I Gusti Made Sudika
Keyword(s):  
Reinforced Concrete ◽  
Concrete Slab ◽  
Pushover Analysis ◽  
Floor Plate ◽  
Performance Level ◽  
Building Structure ◽  
Conventional Concrete ◽  
Safety Level ◽  
Reinforced Concrete Building ◽  
Concrete Building

The Structure of Reinforced concrete building using kalsi floor plate is one alternative for reduced the weight of the building structure. The floor plate usually used conventional concrete, can be replaced with kalsi floor 20. The aim of the research is to analysis of the behavior of reinforced concrete building using conventional concrete slabs and kalsi floor 20. The building structure as the model in this research is the building structure of four floors and was designed to follow the rules of SNI 2847: 2013. Evaluation of seismic behavior in accordance with the SNI 1726: 2012 was conducted out by applying pushover analysis using SAP 2000 software. The analysis results showed that drift ratio of plates floor structure models smaller than the kalsi floor plate structure. The pushover analysis results show the level of performance of all structural models according to FEMA-356 / ATC-40 able to provide nonlinear behavior which is indicated by the initial phase of the majority of plastic joints on beam elements and beam sway mechanism. The performance level of the structure with conventional concrete slab includes at immediate occupancy level, while the performance level of the structure with with kalsi floor plate includes at life safety level.

scholarly journals Seismic Performance Assessment of a Moment-Frame Reinforced Concrete Building Typology

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Marsed Leti
Keyword(s):  
Reinforced Concrete ◽  
Dynamic Analysis ◽  
Pushover Analysis ◽  
Shear Walls ◽  
Seismic Performance Assessment ◽  
Moment Frame ◽  
Limit States ◽  
Reinforced Concrete Building ◽  
Concrete Building ◽  
Building Typology

This study covers the application of Static and Dynamic nonlinear analysis to an old moment-frame reinforced concrete building. The case study selected is a template one designed in 1982 without shear walls and built throughout Albanian region in the communism era using old standards (KTP 2-78). For the capacity calculation, Pushover analysis is performed using an inverse triangular load pattern. The demand calculation is conducted using Incremental Dynamic Analysis (IDA) as a method which provides the response behavior of the structure from the elastic range until collapse. For the dynamic analysis is used a set of 18 earthquakes with no marks of directivity. Limit states are defined for both Pushover and IDA based on the FEMA 356 guidelines. The mathematical model is prepared in the environment of Zeus-NL, a software developed especially for earthquake applications. The parameters defined for the IDA analysis are 5% damped first mode spectral acceleration (Sa(T1,5%)) for the intensity measure (IM) and maximum global drift ratio (ϴmax) for the damage measure (DM). In addition, limit states are selected for the pushover curve as Immediate Occupancy (IO), Life Safety (LS) and Collapse Prevention (CP). Similarly, for the IDA curve the limit states are selected as IO, CP and Global Instability (GI) based on FEMA guidelines. Furthermore, IDA curves are summarized into 16%, 50% and 84% fractiles as suggested in the literature. Additionally, a comparison between Pushover and IDA median (50% fractile) is shown from the same graph to illustrate the correlations between performance levels. Finally, structural performance is interpreted based on the outcomes.

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