scholarly journals A STUDY ON FLUCTUATION OF AXIAL LOAD OF COLUMNS WITHIN A MOMENT-RESISTING MEDIUM-RISE RC BUILDING SUBJECTED TO BI-DIRECTIONAL STRONG GROUND MOTIONS

Author(s):  
◽  
Tetsuo KUBO
Author(s):  
Ehsan Khojastehfar ◽  
Farzad Mirzaei Aminian ◽  
Hamid Ghanbari

Characteristics of earthquake strong ground motions play an important role in the calculation of seismic-induced risk imposed on the structures. Distinguished features exist in movements recorded near seismic sources, as a result of a substantial amount of energy in a short period of record arrival time. In this article, seismic risk analysis of concrete moment-resisting frames due to near-fault strong ground motion is calculated and compared with that of caused by far-field strong ground motions. To achieve this goal, three moment-resisting frames with 4, 6, and 10 stories were designed based on international seismic design code. These frames are modeled applying modified Ibarra–Krawinkler moment–rotation nonlinear model in which strength and stiffness deterioration are involved. Seismic risk analysis of the frames is implemented using the Pacific Earthquake Engineering Research Center approach. Through this approach, probabilistic seismic hazard, probabilistic structural demand, probabilistic structural damage, and probabilistic loss curves are combined. Mean annual frequency of exceedance of seismic-induced losses presents probabilistic seismic risk of the sampled frames. According to the achieved results, the four-story frame (representative of low-rise frames) is more prone to be affected by near-fault strong ground motions in view of calculated seismic-induced risks.


2015 ◽  
Vol 9 (1) ◽  
pp. 351-362 ◽  
Author(s):  
Juan Carlos Vielma Pérez ◽  
Manuel Antonio Cando Loachamín

Current earthquake-resistant procedures prescribe generic values for the response reductions factors, regardless of the configurational characteristics of the designed buildings. It is well know that these response reduction factors values reflect the expected behavior of the structures when they are under strong ground motions, being this seismic behavior usually evaluated through ductility and over-strength. In this work calculated values of the ductility of special moment-resisting steel frames with different span lengths and designed according the Ecuadorian Construction Code are presented. Results show that the buildings’ ductility is strongly influenced by the spans length and they would reach inadequate values if the second-order effect P-Δ occur, and then indicating that the structures are more vulnerable than structures not affected by P-Δ effect.


2019 ◽  
Vol 35 (1) ◽  
pp. 289-310 ◽  
Author(s):  
Randy Tenderan ◽  
Takanori Ishida ◽  
Yu Jiao ◽  
Satoshi Yamada

This study evaluates the seismic performance of steel moment-resisting frames (SMRFs) under multiple strong ground motions. The cumulative damage of beam members is used as the main damage index. A cumulative damage formula is generated based on the experimental results of the steel beam-to-column connection test considering the ductile fracture. Local buckling of members is not considered in this study. Six SMRF models with two parameters (the number of stories and the strength of the column base) are analyzed by conducting an inelastic response analysis. Three different ground motion intensities (peak ground velocity = 0.5 m/s (design level), 0.75 m/s, and 1.0 m/s), each with five repeated excitations are used in the inelastic response analysis to simulate the occurrence of multiple strong ground motions. Stable behavior with a linear increment in cumulative damage is found in most cases, especially when the ground motion intensity is equal to the design level. However, when the intensity is greater than the design level, both ductile fracture and weak story collapse are observed in several cases.


2021 ◽  
Vol 11 (15) ◽  
pp. 7041
Author(s):  
Baoyintu Baoyintu ◽  
Naren Mandula ◽  
Hiroshi Kawase

We used the Green’s function summation method together with the randomly perturbed asperity sources to sum up broadband statistical Green’s functions of a moderate-size source and predict strong ground motions due to the expected M8.1 to 8.7 Nankai-Trough earthquakes along the southern coast of western Japan. We successfully simulated seismic intensity distributions similar to the past earthquakes and strong ground motions similar to the empirical attenuation relations of peak ground acceleration and velocity. Using these results, we predicted building damage by non-linear response analyses and find that at the regions close to the source, as well as regions with relatively thick, soft sediments such as the shoreline and alluvium valleys along the rivers, there is a possibility of severe damage regardless of the types of buildings. Moreover, the predicted damage ratios for buildings built before 1981 are much higher than those built after because of the significant code modifications in 1981. We also find that the damage ratio is highest for steel buildings, followed by wooden houses, and then reinforced concrete buildings.


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