Effect of soil conditions on the response of reinforced concrete tall structures to near-fault earthquakes

A typical reinforced concrete rib arch bridge was chosen to investigate its nonlinear response to near-fault ground motions recorded in 2008 Wenchuan earthquake. Results showed that significant seismic damage may occur, maximum demands were higher for near-fault records having forward directive than far-fault motions, and the rotational capacity of rib plastic hinge is not enough for the large compression force of arch rib. While backward-directivity motions, typically do not exhibit pulse-type motions, only have medium seismic damage to the arch bridge.

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Study on Structural Collapse Behavior of Reinforced Concrete Building Under Near-Fault Earthquakes

Lecture Notes in Civil Engineering - EASEC16 ◽

10.1007/978-981-15-8079-6_73 ◽

2020 ◽

pp. 771-779

Author(s):

F. P. Hsiao ◽

P. W. Weng ◽

W. C. Shen ◽

Y. A. Li ◽

R. J. Tsai ◽

...

Keyword(s):

Reinforced Concrete ◽

Structural Collapse ◽

Reinforced Concrete Building ◽

Near Fault ◽

Concrete Building ◽

Collapse Behavior ◽

Near Fault Earthquakes

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Analytical study to evaluate the effect of higher modes of reinforced concrete moment-resisting frames with thin steel shear wall under simple pulse

Advances in Structural Engineering ◽

10.1177/1369433218773241 ◽

2018 ◽

Vol 21 (15) ◽

pp. 2311-2325 ◽

Cited By ~ 3

Author(s):

S Reza Salimbahrami ◽

Majid Gholhaki

Keyword(s):

Reinforced Concrete ◽

Shear Force ◽

Flexible Structures ◽

Shear Wall ◽

Moment Frames ◽

Maximum Displacement ◽

Higher Modes ◽

Near Fault ◽

Steel Shear Wall ◽

Near Fault Earthquakes

The response of flexible structures with long period to near-fault earthquakes shows an imposed demand on these structures which exceeds their capacity. Also, the relationship between frequency content of earthquake and the main frequency of structure is a significant parameter to the response of structure. Therefore, the sensitivity of the response of structure to period of pulse and the lack of enough records for near-fault earthquakes with different amounts of period of pulse is the most important challenge of structural analysis. Of all methods for this analysis, proposed model by Agraval was used in this study. To achieve this goal, various ratios of period of pulse to main period of structure ( Tp/ T1) were considered, where the effect of higher modes on estimating displacement demands was assessed. Meanwhile, the distribution of shear forces for 6-, 12-, and 24-story reinforced concrete moment frames with steel shear wall was evaluated. The results showed that maximum displacement and force demands were obtained for different structures with Tp/ T1 = 1. Meanwhile, by increasing the number of stories, the effect of higher modes decreased and structures tended to fluctuate in first mode. Furthermore, the most effect of higher modes was obtained for shear force at the roof ( Vroof) and then base shear force ( Vbase), where displacement of roof ( Uroof) did not have any effect on the period of models.

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A new ground motion intensity measure for short period reinforced concrete structures subjected to near-fault pulse-like ground motions

Mechanics Based Design of Structures and Machines ◽

10.1080/15397734.2021.1886114 ◽

2021 ◽

pp. 1-16

Author(s):

Cengizhan Durucan ◽

Hümeyra Şahin ◽

Ayşe Ruşen Durucan

Keyword(s):

Reinforced Concrete ◽

Ground Motion ◽

Ground Motions ◽

Concrete Structures ◽

Reinforced Concrete Structures ◽

Intensity Measure ◽

Near Fault ◽

Short Period ◽

Ground Motion Intensity Measure

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Influence of Elastomeric Bearings in Tension on the Seismic Performance of Base-Isolated r.c. Buildings

Applied Sciences ◽

10.3390/app11010082 ◽

2020 ◽

Vol 11 (1) ◽

pp. 82

Author(s):

Fabio Mazza ◽

Mirko Mazza

Keyword(s):

Base Isolation ◽

Nonlinear Models ◽

Vertical Component ◽

Computer Code ◽

Nonlinear Phenomena ◽

Isolation System ◽

Elastomeric Bearings ◽

Near Fault ◽

Base Isolation System ◽

Near Fault Earthquakes

Elastomeric bearings are commonly used in base-isolation systems to protect the structures from earthquake damages. Their design is usually developed by using nonlinear models where only the effects of shear and compressive loads are considered, but uncertainties still remain about consequences of the tensile loads produced by severe earthquakes like the near-fault ones. The present work aims to highlight the relapses of tension on the response of bearings and superstructure. To this end, three-, seven- and ten-storey r.c. framed buildings are designed in line with the current Italian seismic code, with a base-isolation system constituted of High-Damping-Rubber Bearings (HDRBs) designed for three values of the ratio between the vertical and horizontal stiffnesses. Experimental and analytical results available in literature are used to propose a unified nonlinear model of the HDRBs, including cavitation and post-cavitation of the elastomer. Nonlinear incremental dynamic analyses of the test structures are carried out using a homemade computer code, where other models of HDRBs considering only some nonlinear phenomena are implemented. Near-fault earthquakes with comparable horizontal and vertical components, prevailing horizontal component and prevailing vertical component are considered as seismic input. Numerical results highlight that a precautionary estimation of response parameters of the HDRBs is attained referring to the proposed model, while its effects on the nonlinear response of the superstructure are less conservative.

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Seismic Response of RC Frames with a Soft First Story Retrofitted with Hysteretic Dampers under Near-Fault Earthquakes

Applied Sciences ◽

10.3390/app11031290 ◽

2021 ◽

Vol 11 (3) ◽

pp. 1290

Author(s):

Santiago Mota-Páez ◽

David Escolano-Margarit ◽

Amadeo Benavent-Climent

Keyword(s):

Cost Effective ◽

Far Field ◽

Soft Story ◽

Near Fault ◽

Rc Frames ◽

Story Drift ◽

Number Of Cycles ◽

Rc Frame Structures ◽

Near Fault Earthquakes ◽

Hysteretic Dampers

Reinforced concrete (RC) frame structures with open first stories and masonry infill walls at the upper stories are very common in seismic areas. Under strong earthquakes, most of the energy dissipation demand imposed by the earthquake concentrates in the first story, and this eventually leads the building to collapse. A very efficient and cost-effective solution for the seismic upgrading of this type of structure consists of installing hysteretic dampers in the first story. This paper investigates the response of RC soft-story frames retrofitted with hysteretic dampers subjected to near-fault ground motions in terms of maximum displacements and lateral seismic forces and compares them with those obtained by far-field earthquakes. It is found that for similar levels of total seismic input energy, the maximum displacements in the first story caused by near-fault earthquakes are about 1.3 times larger than those under far-field earthquakes, while the maximum inter-story drift in the upper stories and the distribution and values of the lateral forces are scarcely affected. It is concluded that the maximum displacements can be easily predicted from the energy balance of the structure by using appropriate values for the parameter that reflects the influence of the impulsivity of the ground motion: the so-called equivalent number of cycles.

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