scholarly journals Impact of the Vertical Component of Earthquake Ground Motion in the Performance Level of Steel Buildings

2021 ◽  
Vol 11 (4) ◽  
pp. 1925
Author(s):  
Jesús-Gerardo Valdés-Vázquez ◽  
Adrián David García-Soto ◽  
Miguel Á. Jaimes

This study discusses the impact of the vertical component of earthquake ground motion in the performance level of steel building subjected to earthquake excitations. Analyses are carried out for the strong column-weak beam philosophy because the structural performance is focused on these elements. A realistic steel frame is also considered to investigate the impact of including the seismic vertical component in the non-linear response of the building. The main findings of this study are: (1) When an analysis is performed by considering the horizontal and vertical components of ground motion acting simultaneously (near the causative fault), larger plastic rotations in the beams are obtained as compared to those resulting by considering only the horizontal component. (2) Due to the previous finding, if a codified criterion to inspect the steel beams performance in terms of the plastic rotation is considered, the beam performance could lie within a different acceptation criterion (i.e., from immediate occupancy to collapse prevention) if the vertical component is included in the analysis.

2019 ◽  
Vol 5 (2) ◽  
pp. 466
Author(s):  
Mustafa Shakir Farman ◽  
AbdulMuttalib Isa Said

Recently, Iraq has experienced an increase in seismic activity, especially, near the east boundary with Iran which enhanced the need to study its effect on the behavior of buildings. In this study, a comprehensive methodology was applied to investigate the behavior of a moment frame system with respect to its height after subjected to the design ground motion at Baghdad according to the recently developed seismic hazard maps and, after developing and designing the required configurations of archetype models, specifying life safety as an aimed performance level, modeling nonlinearity and applying the nonlinear static analysis (NSP) according to ASCE/SEI41-13, FEMA356 and FEMA P-695. This methodology is started by sizing members cross-sectional dimensions and applying reinforcement detailing requirements according to ACI318-14. Results show that, for a given building height and number of bays, inelastic drifts increase with decreasing the bay width because the overall building stiffness is decreased and it will be more slender, and consequently, the P- delta effects increased. Also, as the building height increased, both, target and minimum shear capacities decrease and the target displacement increases under the effect of the same earthquake ground motion. Consequently, a necessary limitation on the height of these buildings were deduced to ensure their ability to withstand the future ground shaking and, in the same time, maintaining the life safety performance level of damage. Where, it is found that the maximum allowed heights of framed buildings in Baghdad are 17, 25 and 32 stories for 6, 7.5 and 9 m bay widths, respectively.


Author(s):  
Lyle P. Carden ◽  
Barry J. Davidson ◽  
Tam J. Larkin ◽  
Ian G. Buckle

Recent earthquakes have shown that a large magnitude, long period pulse is often prevalent in ground motion records at sites within a few kilometres of the active fault during an earthquake. Near-field earthquake ground motion containing forward directivity effects can result in a larger response in flexible structures, such as seismically isolated structures, compared to that predicted for conventional ground shaking. Hence, a study was performed on a number of generic seismically isolated structures designed to the 1997 Uniform Building Code, as well as a case study on the William Clayton building in Wellington, to determine the impact of near-field ground motion. In optimising the performance of the buildings for both near-field and original "design level" earthquakes, it is concluded that linear viscous dampers added to the existing isolation systems are effective in controlling the response during large magnitude near-field earthquakes with minimal impact on the design response. Additional viscous damping is more effective than hysteretic damping in limiting isolator displacements while also preventing an increase in base shear and floor accelerations for far-field "design level" earthquakes.


Author(s):  
Erika Schiappapietra ◽  
Chiara Smerzini

AbstractThis paper investigates the spatial correlation of response spectral accelerations from a set of broadband physics-based ground motion simulations generated for the Norcia (Central Italy) area by means of the SPEED software. We produce several ground-motion scenarios by varying either the slip distribution or the hypocentral location as well as the magnitude to systematically explore the impact of such physical parameters on spatial correlations. We extend our analysis to other ground-motion components (vertical, fault-parallel, fault-normal) in addition to the more classic geometric mean to highlight possible ground-motion directionality and therefore identify specific spatial correlation features. Our analyses provide useful insights on the role of slip heterogeneities as well as the relative position between hypocentre and slip asperities on the spatial correlation. Indeed, we found a significant variability in terms of both range and sill among the considered case studies, suggesting that the spatial correlation is not only period-dependent, but also scenario-dependent. Finally, our results reveal that the isotropy assumption may represent an oversimplification especially in the near-field and thus it may be unsuitable for assessing the seismic risk of spatially-distributed infrastructures and portfolios of buildings.


EXTRAPOLASI ◽  
2021 ◽  
Vol 18 (1) ◽  
pp. 33-41
Author(s):  
Nurul Rochmah ◽  
Michella Beatrix ◽  
Bantot Sutriono

AbstractIndonesia is a ring of fire area where earthquakes frequently occur. By realizing this, buildings in Indonesia need to calculate earthquake loads based on SNI 03-1726-2019 to minimize victims due to building collapse when earthquakes occur.It is also necessary to evaluate the performance level of a building, in this case a 6-storey building located in the Malang area. For determining the level of performance, a method called Non-Linear Time History Analysis is used. In this calculation used San Fernando, Kobe and Landers ground motion.Based on the results from the evaluation using the Non-Linear Time History method got the maximum drift story 0.137 m that occurs in Kobe ground motion. So that the maximum total drift Dt / H is 0.137 / 21.95 = 0.0063 <0.01. Based on these results, the building performance level includes IO (Immediate Occupancy).  AbstrakIndonesia termasuk daerah ring of fire dimana suatu daerah yang sering terjadi gempa. Dengan menyadari hal tersebut, bangunan-bangunan yang ada di Indonesia perlu memperhitungkan beban gempa yang ada berdasarkan SNI 03-1726-2019 untuk meminimalisir korban akibat keruntuhan bangungan yang terjadi akibat gempa. Karena itu perlu juga untuk mengevaluasi level kinerja suatu gedung dalam hal ini gedung 6 lantai yang terletak di daerah Malang. Pada gedung ini untuk dapat diketahui level kinerjanya, maka, digunakan metode yang bernama Non-Linear Time History Analisis. Ground motion yang dipakai adalah San Fernando, Kobe dan LandersBerdasarkan hasil yang diperoleh dari evaluasi dengan metode Non-Linear Time History Analisis ini adalah maximum drift story terbesar adalah 0,137 m yang terjadi pada ground motion Kobe. Sehingga Maximum total driftnya Dt/H adalah 0,137/21,95 =0,0063<0,01. Berdasar hasil tersebut lever kinerja gedung termasuk IO (Immediate Occupancy).


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