Effect of Supporting Structure’s Torsion on Floor Acceleration Demands in Buildings on Slopes

2021 ◽  
pp. 185-196
Author(s):  
Ankur Jain ◽  
Mitesh Surana
Keyword(s):  
Floor Acceleration

Evaluation of floor acceleration demands from the 2017 Mexico City code seismic provisions using a continuous elastic model and records of instrumented buildings

2020 ◽  
Vol 36 (2_suppl) ◽  
pp. 213-237
Author(s):  
Miguel A Jaimes ◽  
Adrián D García-Soto
Keyword(s):  
Mexico City ◽  
Seismic Design ◽  
Soft Soil ◽  
Response Spectra ◽  
Elastic Model ◽  
Ground Acceleration ◽  
Nonstructural Components ◽  
Floor Response Spectra ◽  
Instrumented Buildings ◽  
Floor Acceleration

This study presents an evaluation of floor acceleration demands for the design of rigid and flexible acceleration-sensitive nonstructural components in buildings, calculated using the most recent Mexico City seismic design provisions, released in 2017. This evaluation includes two approaches: (1) a simplified continuous elastic model and (2) using recordings from 10 instrumented buildings located in Mexico City. The study found that peak floor elastic acceleration demands imposed on rigid nonstructural components into buildings situated in Mexico City might reach values of 4.8 and 6.4 times the peak ground acceleration at rock and soft sites, respectively. The peak elastic acceleration demands imposed on flexible nonstructural components in all floors, estimated using floor response spectra, might be four times larger than the maximum acceleration of the floor at the point of support of the component for buildings located in rock and soft soil. Comparison of results from the two approaches with the current seismic design provisions revealed that the peak acceleration demands and floor response spectra computed with the current 2017 Mexico City seismic design provisions are, in general, adequate.

scholarly journals Evaluation of the Floor Acceleration Amplification Demand of Instrumented Buildings

2021 ◽  
Vol 2021 ◽  
pp. 1-20
Author(s):  
Baofeng Huang ◽  
Wensheng Lu
Keyword(s):  
Strong Motion ◽  
Critical Parameters ◽  
Acceleration Response ◽  
Distribution Profile ◽  
Parabolic Distribution ◽  
Acceleration Amplification ◽  
Seismic Force ◽  
Importance Factor ◽  
Instrumented Buildings ◽  
Floor Acceleration

The floor acceleration amplification (FAA) factor is one of the most critical parameters in computing the equivalent seismic force of nonstructural component (NC). To evaluate the heightwise FAA distribution profile, the recorded acceleration response of the instrumented buildings was analyzed using the California Strong Motion Instrumentation Program (CSMIP) database. The FAA demands for three groups of buildings consisting of reinforced concrete, steel, and masonry buildings were analyzed. In each group, the buildings were classified into four subgroups according to their heights. Parabolic distribution profiles were suggested that could envelop most of the FAA data, as demonstrated by the processed results. An earthquake experience-based importance factor was suggested in terms of the percentage of the enveloped records. The obtained FAAs at the roof were generally larger than those in other levels. The percentile distributions of the roof acceleration amplification (RAA) were computed. The results showed that the roof FAA was underestimated in ASCE 7-16. The magnitudes of the FAA and the RAA correlated to the fundamental period of the building, which was considered by classifying the buildings according to the period ranges. The RAA profile against the period was obtained from a regression analysis. The developed FAA profile is expected to be useful in the seismic design of NCs, and it is expected to be adopted in future code provisions.

scholarly journals Impact Response of Base Isolated Building with Adjacent Structures

10.29007/275r ◽  
2018 ◽  
Author(s):  
Niraj Shinde ◽  
Devesh Soni
Keyword(s):  
Impact Response ◽  
Gap Effect ◽  
Viscous Damper ◽  
Base Shear ◽  
Pendulum System ◽  
Adjacent Structure ◽  
Adjacent Structures ◽  
Impact Element ◽  
The Impact ◽  
Floor Acceleration

The seismic behavior of multi-storied building supported on Friction pendulum system (FPS) during impact with adjacent structure is examined. One lateral degree of freedom is considered at each floor, base mass and slider. Adjacent structure (i.e. retaining walls or entry bridges) is modeled as an impact element in form of spring and dashpot. The impact response of FPS bearing is studied under 60 records consisting of service level, design basis and maximum credible earthquakes. Newmark’s step by step iteration method is used to solve the differential equations of motion for the isolated system. The impact response of isolated building is studied under the variation of important system parameters such as size of gap and stiffness of impact element. To reduce the influence of impact a viscous damper is employed between the isolated building and adjacent structure. It is concluded that during impact with adjacent structure the superstructure acceleration and base shear increases while bearing displacement decreases. The employment of viscous damper shows considerable reduction in bearing displacements, base shear and impact force during DBE and MCE events. Further, the effects of impact are found critical if the superstructure is flexible and greater stiffness of impact element. The top floor acceleration increases with the isolation gap up to certain limit and again reduces with the increase in isolation gap.Keywords - Adjacent Structure; isolation; Sliding bearing; Viscous Damper; Gap effect; Floor acceleration; Impact

Code-oriented floor acceleration spectra for building structures

2016 ◽  
Vol 15 (7) ◽  
pp. 3013-3026 ◽  
Author(s):  
Vladimir Vukobratović ◽  
Peter Fajfar
Keyword(s):  
Building Structures ◽  
Floor Acceleration

scholarly journals Uniform hazard floor acceleration spectra for linear structures

2016 ◽  
Vol 46 (7) ◽  
pp. 1121-1140 ◽  
Author(s):  
Andrea Lucchini ◽  
Paolo Franchin ◽  
Fabrizio Mollaioli
Keyword(s):  
Linear Structures ◽  
Floor Acceleration

A comparative study of floor accelerations of different structural systems with lead-rubber-bearing (LRB) isolators

2020 ◽  
Author(s):  
Ali Ruzi Özuygur
Keyword(s):  
Base Isolation ◽  
Damping Ratio ◽  
Dual System ◽  
Base Shear ◽  
Nonstructural Components ◽  
Moment Resisting Frame ◽  
Lead Rubber Bearing ◽  
Moment Resisting ◽  
Seismic Base Isolation ◽  
Floor Acceleration

Seismic base isolation has been successfully used to protect structural and nonstructural components from the damaging effects of earthquakes by reducing floor accelerations and inter-story drifts for decades. The level of floor acceleration is a key issue in the protection of acceleration-sensitive nonstructural components. In this paper, floor acceleration performance of seismically isolated buildings with different lateral load resisting systems such as moment resisting frame, dual system, moment resisting frame plus viscous wall dampers and dual system plus viscous wall dampers is investigated. Moreover, the effectiveness of supplemental viscous damping devices equipped in parallel with lead-rubber isolators is studied. It is inferred from the study that the most effective way of reducing floor accelerations is to provide more rigidity to the superstructure. Utilizing supplemental viscous dampers along with lead-rubber isolators having about 20% of effective damping ratio is meaningless or harmful in relation to floor acceleration and base shear.

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