scholarly journals Seismic Assessment and Rehabilitation of a RC Structure Under Mainshock-Aftershock Seismic Sequences Using Beam-Column Bonded CFRP Strategy

2021 ◽  
Author(s):  
Omid Karimzade Soureshjani ◽  
Gholamreza Nouri
Keyword(s):  
Structural Damage ◽  
Seismic Behavior ◽  
Aftershock Sequence ◽  
Average Growth ◽  
Seismic Sequences ◽  
Weak Beam ◽  
Drift Ratio ◽  
Rc Structure ◽  
Specific Performance ◽  
Story Drift

Abstract A mainshock is usually accompanied by a group of ground motions. In many design codes, the effects of the seismic sequences have been neglected or underestimated. Aftershocks can increase structural damage or even cause failure. The current study evaluated the seismic behavior of a rehabilitated and as-built RC structure under real scaled mainshock-aftershocks using nonlinear analysis. Verification was done in two modes. The inter-story drift ratio, maximum residual, and relative displacements were studied. The seismic study of the as-built structure showed that the residual displacement grew, on average, more than 90% under the mainshock-aftershock sequence compared to the mainshock-only record. A beam-column bonded CFRP rehabilitation strategy using six layers of T-700 CFRP was chosen based on the specific performance level. The strategy showed the ability to transfer the plastic strain from the columns to the beams, which could be considered as a change from a weak column-strong beam concept to a strong column-weak beam concept. Compared to the as-built structure under the seismic sequences, the rehabilitated structure showed an average growth of 78% in the first-story drift ratio, which was significant. Unlike the as-built structure, seismic sequences caused no growth drift in the rehabilitated structure. It also was observed that the ratio of aftershock PGA to mainshock PGA could have an intensive effect on the seismic behavior of both rehabilitated and as-built structures.

scholarly journals Seismic Behavior of RC Moment Resisting Structures with Concrete Shear Wall under Mainshock-aftershock Seismic Sequences

2021 ◽  
Author(s):  
Omid Karimzade Soureshjani ◽  
Ali Massumi
Keyword(s):  
Seismic Behavior ◽  
Shear Wall ◽  
Relative Displacement ◽  
Structure Model ◽  
Residual Displacement ◽  
Significant Growth ◽  
Seismic Sequences ◽  
Drift Ratio ◽  
Story Drift ◽  
Moment Resisting

Abstract A structure may subject to several aftershocks after a mainshock. In many seismic design provisions, the effect of the seismic sequences is not directly considered or underestimated. This paper studies the seismic behavior of RC moment-resisting structures with concrete shear wall under seismic sequences. Two three-dimensional structures of short and medium height were designed and analyzed. The former models were studied under a group of real mainshock-aftershock seismic sequences. The models were loaded and designed according to the fourth edition of the Iranian seismic code of standard no. 2800 and ACI-318 respectively. Furthermore, the non-linear dynamic time-history finite element analysis of models was performed via the explicit method. The parameters of maximum displacement, inter-story drift ratio, residual displacement, and finally the effect of the ratio of aftershock acceleration to mainshock acceleration were investigated and assessed. Due to the high lateral stiffness of shear walls, parallel with the complete elastic behavior, aftershocks cause no growth in inter-story drift ratio and relative displacement in the short structure model. In contrast, compared to the structure under the solely mainshock, the medium height structure model under seismic sequences showed significant growth in the amount of relative displacement (even more than 50% growth), inter-story drift ratio, plastic strain, and residual displacement (almost 30% growth). Furthermore, unlike the moment-resisting frame structures, models showed no significant growth in the drift ratio with the height. Assessments indicated that the ratio of aftershock to mainshock acceleration is a determinative parameter in structural behavior under seismic sequences.

Seismic Behavior Factor of Moment Resisting Steel Frame-Steel Plate Shear Wall

2014 ◽  
Vol 638-640 ◽  
pp. 1932-1936 ◽  
Author(s):  
Jian Hua Shao ◽  
Qun Wu
Keyword(s):  
Seismic Behavior ◽  
Steel Plate ◽  
Shear Wall ◽  
Reduction Factor ◽  
Steel Frame ◽  
Steel Plate Shear Wall ◽  
Behavior Factor ◽  
Drift Ratio ◽  
Story Drift ◽  
Moment Resisting

The seismic behavior factor of moment resisting steel frame-steel plate shear wall under two different horizontal loading patterns was investigated according to the maximum inter-story drift ratio reaching 1/50. It could be achieved with the same calculated standard as the foreign codes and the determined behavior factor was compared with foreign research results. The method using the software SAP2000 to calculate seismic behavior factor according to the maximum inter-story drift ratio reaching 1/50 was presented and the specific example was used to elaborate the operating process. The seismic behavior factor R, the overstrength factor RΩ and the ductility reduction factor Rμ of 10-storey 3-span steel frame-steel plate shear wall under the inverted triangle load are respectively 6.07, 2.96 and 2.05. while they are respectively 7.2, 3.37 and 2.13 under the uniform load. Finally, it can be concluded that the economic and reasonable design goals are achieved for this structure.

Building Seismic Vulnerability Study for China High Rises

2013 ◽  
Vol 353-356 ◽  
pp. 2301-2304
Author(s):  
Fan Wu ◽  
Ming Wang ◽  
Xin Yuan Yang
Keyword(s):  
Ground Motion ◽  
Structural Damage ◽  
Seismic Vulnerability ◽  
Fragility Curves ◽  
Response Spectrum ◽  
Earthquake Ground Motion ◽  
Published Data ◽  
Rapid Urbanization ◽  
High Rise ◽  
Story Drift

High-rise buildings, as a result of rapid urbanization in China, become one of popular structure kind. However, there have been few seismic vulnerability studies on high-rise buildings, and few fragility curves have been developed for the buildings. Based on the published data of more than 50 high rises and super high rises, the structural information such as building heights, mode periods, locations and sites, the maximum design story drift ratios, are collected and analyzed. The vulnerability analysis for high rises uses response spectrum displacement as seismic ground motion input, since the structures have comparatively long natural period. Using statistics and regression analysis, the relationship between the maximum story drift ratio and response spectrum displacement is established. Based on height groups and earthquake design codes, the fragility curves of different performance levels can be developed. These curves can provide good loss estimation of high rise structural damage under earthquake ground motion.

Corrosion effects on seismic capacity of reinforced concrete structures

2019 ◽  
Vol 37 (1) ◽  
pp. 45-56 ◽  
Author(s):  
Antonio Bossio ◽  
Francesco Fabbrocino ◽  
Tullio Monetta ◽  
Gian Piero Lignola ◽  
Andrea Prota ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Service Life ◽  
Seismic Behavior ◽  
Concrete Cover ◽  
Residual Service Life ◽  
Seismic Capacity ◽  
Rc Structures ◽  
Behavior Simulation ◽  
Cover Cracking ◽  
Rc Structure

AbstractRecently, corrosion prevention and monitoring of reinforced concrete (RC) structures became an important issue for seismic assessment of such kind of structures. Therefore, it is important to develop adequate models to represent material degradation into seismic behavior simulation of RC structures. Because of its effects, corrosion represents the most important form of degradation for materials and structures, both for wide diffusion and the amount of danger it presents. To understand the corrosion process is critical in order to design RC structures that are able to guarantee the required service life and in order to understand the residual service life and strength of an existing structure. The seismic behavior of a corroded framed RC structure is analyzed by means of push-over analyses, which allow understanding the development of the global behavior of the structure. Three different degrees of corrosion penetration were simulated, by means of the reduction of bars and stirrups’ diameters and concrete cover cracking and spalling, and three different configurations of corrosion, depending on the number of corroded frames and sides of the structural elements.

The influence of construction joint on the seismic behavior of reinforced concrete frame structure

2016 ◽  
Vol 20 (7) ◽  
pp. 1125-1138 ◽  
Author(s):  
Jing Yu ◽  
Xiaojun Liu ◽  
Xingwen Liang
Keyword(s):  
Reinforced Concrete ◽  
Seismic Behavior ◽  
Numerical Models ◽  
Time History ◽  
Frame Structure ◽  
Nonlinear Time History Analysis ◽  
Reinforced Concrete Frame ◽  
Concrete Frame ◽  
Construction Joint ◽  
Story Drift

A new model that can simulate the behavior of construction joint subjected to seismic forces was proposed. Nonlinear time-history analysis was carried out for reinforced concrete regular frame structures designed in different seismic intensity regions as well as with different height-to-width ratios. Two kinds of numerical models are adopted to simulate the seismic behavior of each frame, one with construction joint using the new proposed model and the other without construction joint using the conventional model. Results show that the influence of construction joint on the seismic behavior of reinforced concrete frame is strongly related to structural nonlinearity. It may increase the top displacement and the inter-story drift, change the inter-story drift distributions, and exacerbated the local reaction of key members. The influence of construction joint cannot be ignored for structures with low emergency capacity against major earthquake. Seismic design suggestions are proposed from the aspect of calculation analysis method.

Seismic Behavior of Blocky Masonry Structures

2000 ◽  
Vol 16 (2) ◽  
pp. 337-365 ◽  
Author(s):  
Joa~o Azevedo ◽  
Gabriela Sincraian ◽  
J. V. Lemos
Keyword(s):  
Discrete Element Method ◽  
Structural Damage ◽  
Seismic Behavior ◽  
Seismic Vulnerability ◽  
Crack Opening ◽  
Structural Systems ◽  
Masonry Structures ◽  
Block Interaction ◽  
Steel Cables ◽  
Vulnerability Functions

The seismic behavior of structures composed by masonry blocks is analyzed using the discrete element method. Some features of the method are described including the representation of the block deformation, contacts and block interaction. The suitability of the method for the analysis of masonry structures is examined. The seismic behavior of some simple structural systems as well as that of some real structures is studied. It is shown that the method is able to reproduce important phenomena such as crack opening and joint sliding, which are responsible for the occurrence of structural damage and collapse. The collapse patterns of the analyzed structures are examined, reinforcing schemes using steel cables are considered and seismic vulnerability functions are obtained.

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