Base shear capping buildings with graphite-lubricated bases for collapse prevention in extreme earthquakes

2016 ◽  
Vol 46 (6) ◽  
pp. 1003-1021 ◽  
Author(s):  
Francesca Barbagallo ◽  
Ikumi Hamashima ◽  
Hongsong Hu ◽  
Masahiro Kurata ◽  
Masayoshi Nakashima
Keyword(s):  
Base Shear ◽  
Collapse Prevention

scholarly journals Pengaruh Penerapan SNI 1726:2019 Terhadap Desain Struktur Rangka Momen Beton Bertulang Di Indonesia

2021 ◽  
Vol 17 (1) ◽  
pp. 1
Author(s):  
Ahmad Sobah Nurul Sodik ◽  
Relly Andayani
Keyword(s):  
Life Safety ◽  
Base Shear ◽  
Collapse Prevention

Telah diterbitkan peraturan gempa yang terbaru, yaitu tata cara perencanaan ketahanan gempa untuk struktur gedung dan non gedung SNI 1726:2019 menggantikan peraturan gempa sebelumnya, SNI 1726:2012. Dalam penelitian ini spektra desain yang ada dalam SNI 1726:2019 dibandingkan dengan spektra desain dalam SNI 1726:2012 dengan mengambil sampling 21 kota besar yang dianggap mewakili seluruh wilayah Indonesia. Dari hasil perbandingan tampak sebagian besar mengalami kenaikan walaupun tidak sedikit yang mengalami penurunan dan ada pula yang tetap. Penerapan faktor amplifikasi Fa menurut SNI 1726:2019 menyebabkan adanya fenomena anomali di daerah-daerah rawan gempa, dimana nilai spektra desain untuk perioda pendek di situs Tanah Lunak (SE) dapat lebih rendah daripada nilai untuk Tanah Sedang (SD) dan Tanah Keras (SC). Fenomena anomali tersebut terjadi di kota-kota dengan SS di atas 0,75 g. Penelitian dilanjutkan dengan melakukan studi komparasi dengan membandingkan besaran gaya gempa yang dihitung menggunakan SNI 1726:2012 dan SNI 1726:2019 terhadap suatu sampel model struktur gedung yang diasumsikan terletak di Jakarta pada kondisi tanah lunak (SE). Terjadi kenaikan base shear desain pada gedung yang dihitung menggunakan SNI 1726:2019 dibandingkan gedung yang dihitung menggunakan SNI 1726:2012 sebesar 128,93% untuk arah x dan 131,23% untuk arah y. Sampel model struktur gedung memiliki level kinerja life safety jika dievaluasi terhadap peraturan gempa SNI 1726:2012 dan mengalami penurunan kinerja dari level life safety ke collapse prevention jika dievaluasi terhadap gempa peraturan baru, SNI 1726:2019.

scholarly journals Seismic Capacity Assessment of Existing RC Building by Using Pushover Analysis

2018 ◽  
Vol 4 (9) ◽  
pp. 2034 ◽  
Author(s):  
Mohammed Ismaeil
Keyword(s):  
Control Method ◽  
Demand Curve ◽  
Pushover Analysis ◽  
Life Safety ◽  
Base Shear ◽  
Seismic Capacity ◽  
Safety Level ◽  
Collapse Prevention ◽  
Performance Point ◽  
And Performance

The infrastructure, existing in Sudan, is mostly not structured or designed to resist seismic forces accordingly. The study investigated the seismic damage of a 5 storey existing reinforced concrete building in Khartoum, Sudan. Three performance levels were considered in the study, which included immediate occupancy, life safety, and collapse prevention. The gravity push was carried out using force control method and lateral push with displacement control, using SAP2000. Pushover analysis produces push curve, consisting of capacity spectrum, demand spectrum, and performance point. It showed the performance level of building components along with maximum base shear carrying capacity. It has been observed that demand curve intersected the capacity curve between the points B and C at the X direction that is life safety level; and between the points B and C at the Y direction that is life safety and collapse prevention level. Therefore, some building elements are needed to be strengthened.

scholarly journals Comparison of Novel Seismic Protection Devices to Attenuate the Earthquake Induced Energy

Actuators ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 73
Author(s):  
Osman Hansu ◽  
Esra Mete Güneyisi
Keyword(s):  
Lateral Displacement ◽  
Time History ◽  
Seismic Protection ◽  
Base Shear ◽  
Seismic Demands ◽  
Nonlinear Time History Analyses ◽  
History Of ◽  
Protection Devices ◽  
Nonlinear Time History ◽  
Better Than

This study addresses an alternative use of viscous dampers (VDs) associated with buckling restrained braces (BRBs) as innovative seismic protection devices. For this purpose, 4-, 8- and 12-story steel bare frames were designed with 6.5 m equal span length and 4 m story height. Thereafter, they were seismically improved by mounting the VDs and BRBs in three patterns, namely outer bays, inner bays, and all bays over the frame heights. The structures were modeled using SAP 2000 software and evaluated by the nonlinear time history analyses subjected to the six natural ground motions. The seismic responses of the structures were investigated for the lateral displacement, interstory drift, absolute acceleration, maximum base shear, and time history of roof displacement. The results clearly indicated that the VDs and BRBs reduced seismic demands significantly compared to the bare frame. Moreover, the all-bay pattern performed better than the others.

scholarly journals Effect of Bottom Geometry on the Natural Sloshing Motion of Water Inside Tanks: An Experimental Analysis

2021 ◽  
Vol 11 (2) ◽  
pp. 605
Author(s):  
Antonio Agresta ◽  
Nicola Cavalagli ◽  
Chiara Biscarini ◽  
Filippo Ubertini
Keyword(s):  
Energy Dissipation ◽  
Water Depth ◽  
Shear Force ◽  
Experimental Tests ◽  
Shear Load ◽  
Damping Properties ◽  
Base Shear ◽  
Structure Interaction ◽  
Sloshing Phenomenon ◽  
Key Aspects

The present work aims at understanding and modelling some key aspects of the sloshing phenomenon, related to the motion of water inside a container and its effects on the substructure. In particular, the attention is focused on the effects of bottom shapes (flat, sloped and circular) and water depth ratio on the natural sloshing frequencies and damping properties of the inner fluid. To this aim, a series of experimental tests has been carried out on tanks characterised by different bottom shapes installed over a sliding table equipped with a shear load cell for the measurement of the dynamic base shear force. The results are useful for optimising the geometric characteristics of the tank and the fluid mass in order to obtain enhanced energy dissipation performances by exploiting fluid–structure interaction effects.

scholarly journals Tuned Mass Damper Design for Slender Masonry Structures: A Framework for Linear and Nonlinear Analysis

2021 ◽  
Vol 11 (8) ◽  
pp. 3425
Author(s):  
Marco Zucca ◽  
Nicola Longarini ◽  
Marco Simoncelli ◽  
Aly Mousaad Aly
Keyword(s):  
Nonlinear Analysis ◽  
Linear Time ◽  
Design Procedure ◽  
Time History ◽  
Tuned Mass Damper ◽  
Second Phase ◽  
Masonry Structures ◽  
Base Shear ◽  
Mass Damper ◽  
Linear And Nonlinear

The paper presents a proposed framework to optimize the tuned mass damper (TMD) design, useful for seismic improvement of slender masonry structures. A historical masonry chimney located in northern Italy was considered to illustrate the proposed TMD design procedure and to evaluate the seismic performance of the system. The optimization process was subdivided into two fundamental phases. In the first phase, the main TMD parameters were defined starting from the dynamic behavior of the chimney by finite element modeling (FEM). A series of linear time-history analyses were carried out to point out the structural improvements in terms of top displacement, base shear, and bending moment. In the second phase, masonry's nonlinear behavior was considered, and a fiber model of the chimney was implemented. Pushover analyses were performed to obtain the capacity curve of the structure and to evaluate the performance of the TMD. The results of the linear and nonlinear analysis reveal the effectiveness of the proposed TMD design procedure for slender masonry structures.

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