1) The document presents a numerical study evaluating the use of fluid dampers for seismic protection of wood-framed structures.
2) A nonlinear finite element model of a wood-framed shear wall was developed and subjected to earthquake ground motions, both with and without a fluid damper installed diagonally.
3) The results demonstrate that the fluid damper was effective at dissipating a large portion of the seismic energy, reducing the peak drift of the wall by 87% and suppressing the pulse-like response.
Seismic analysis of reinforced concrete frame with steel bracingsTin Bui Van
This document analyzes the seismic performance of a 10-story reinforced concrete frame building with and without steel bracing through computer modeling. Three cases are considered: a bare frame (Case 1), a frame with bracing in the middle bays (Case 2), and a frame with bracing at the corners (Case 3). Results show that Case 2 with middle bracing has the lowest time period, displacements, and drift, indicating it best resists earthquake forces by increasing the lateral stiffness of the frame. While the bare frame has the lowest base shear, the addition of bracing in Cases 2 and 3 significantly improves the seismic performance of the building.
Comparative Study of Seismic Analysis of Building with Light Weight and Conve...Dr. Amarjeet Singh
In recent decades, the lightweight materials are used
in construction instead of conventional material. Lightweight
construction is considered to be favourable due to the saving
in construction cost and materials. AAC block is a lightweight
structural material with excellent acoustic and thermal
insulation properties. Due to the use of lightweight material in
construction in seismic zone reduce the percentage of
damages. In this paper the attempt has been made to carry out
the project comparative study of seismic analysis of building
with lightweight and conventional material. Structural model
of multi storey building (G+3) and analysis is carried out in
STAAD-Pro by RSM (Response Spectrum Method). Building
using infill AAC (Autoclaved aerated concrete) block and
conventional clay brick masonry are designed for the same
seismic hazard in accordance with the applicable provisions
given in Indian codes. The analytical results of the buildings
will be compared. The project is also aimed at getting
familiarity with STAAD-Pro.2008.
This document provides a review of seismic isolation techniques for buildings. It summarizes the current practices of seismic isolation, describes common seismic isolation hardware including elastomeric bearings and sliding bearings, and chronicles the history of seismic isolation through shake table testing. The document also reviews past efforts to achieve three-dimensional seismic isolation and identifies areas where further research is needed, such as protecting nonstructural components from vertical ground motions and mitigating local uplift demands in isolation systems.
Seismic Vulnerability Assessment of Steel Moment Resisting Frame due to Infil...IDES Editor
Steel moment resisting frame with open first storey
(soft storey) is known to perform well compared with the RC
frames during strong earthquake shaking. The presence of
masonry infill wall influences the overall behavior of the
structure when subjected to lateral forces, when masonry infill
are considered to interact with their surrounding frames the
lateral stiffness and lateral load carrying capacity of structure
largely increase. In this paper, the seismic vulnerability of
building with soft storey is shown with an example of G+10
three dimensional (3D) steel frame. The open first storey is
an important functional requirement of almost all the urban
multi-storey buildings, and hence, cannot be eliminated.
Hence some special measures need to be adopted for this
specific situation. The under-lying principle of any solution
to this problem is in increasing the stiffness’s of the first
storey such that the first storey stiffness is at least 50% as
stiff as the second storey, i.e., soft first storeys are to be avoided,
and providing adequate lateral strength in the first storey. In
this paper, stiffness balancing is proposed between the first
and second storey of a steel moment resisting frame building
with open first storey and brick infills as described in models.
A simple example building is analyzed by modeling it with
nine different methods. The stiffness effect on the first storey
is demonstrated through the lateral displacement profile of
the building.
Seismic performance of weak base strong column steel moment framesSebastian Contreras
This document summarizes research on the seismic performance of steel moment frames with weak base connections and strong columns. The researchers analyzed a 4-story steel moment frame building using nonlinear time history analysis with different base connection strengths, including fixed, pinned, and varying hysteretic strengths from 1 to 0.3 times column strength. Results showed promise for weaker base connections but also issues like reduced base stiffness concentrating deformations in the first story. Future work is needed to further evaluate weak-base strong-column systems and address limitations.
“ Study of Sesmic Analysis of Masonry Wall Structure”IJERA Editor
Earthquakes are natural trouble under which disasters are mainly caused by damage or collapse of the structure and other man-made structures. When an earthquake occurs natural period of vibration is more on heavy loaded building and less in light loaded building. If the building is light weighted, i.e. steel is less then economy of structure is also achieved. Hence it is necessary to find out natural/fundamental time period when mass changes with different type of brick masonry and concrete masonry.This is necessary because IS 1893:2002 does not incorporate the effect of mass in a formula which they have mentioned for brick masonary structure. Thedesign will also analyze with ETAB software.
Finite ElementAnalysis of Doubly Curved Thin Concrete ShellsHARISH B A
thin shell is a “Three-dimensional spatial structure made up of one or more curved surfaces whose
thickness is small compared to their other dimensions”. Shells belong to the class of stressed skin structures which,
because of their geometry and small flexural rigidity of the skin, tend to carry loads primarily by direct stresses acting in
their plane. The shells are subjected to pure membrane state of stress, under appropriate loading and boundary
condition the resulting bending and twisting moments are either zero or small which may be neglected. The coordinates
of funicular shells are determined by masonry mould method by developing a computer program. In this study doubly
curved thin shells are analysed using finite element software SAP 2000. Doubly curved shells which are in square plan
having 10mX10m and 15mX15m are considered and shells in rectangular plan having dimensions 10mX15m
and 15mX20m are considered. The behavior of shells under self-weight, live load varying from 0-20KN/m (UDL) is
obtained. In this case study deflection curves, membrane stress and stress contour diagram are obtained. It is observed
that with the increase in rise and thickness of funicular shell the deflection are reduced. The membrane stresses
decreases with the increase in rise and thickness of concrete funicular shell. The aim of this study is to develop shells of
different sizes and investigation is done on the shells by finite element analysis under given uniformly distributed load,
to find out the behavior of shells in various cases using standard software, Structural Analysis Package (SAP 2000).
1. SOM's structural engineering studio develops sustainable structural solutions for tall buildings by drawing inspiration from natural forms and geometries found in nature. These biomimetic designs result in efficient, durable tower structures.
2. For projects like the China World Trade Center and Jinling Hotel Tower, SOM studied the growth patterns of bamboo and applied the efficient bracing and tapering to create tall structures that resist lateral loads.
3. Projects such as the Poly International Plaza and Transbay Tower use intricate grid structures and screen frames derived from hurricanes and nautilus shells to provide strength and allow for open floor plans with minimal material usage.
Seismic analysis of reinforced concrete frame with steel bracingsTin Bui Van
This document analyzes the seismic performance of a 10-story reinforced concrete frame building with and without steel bracing through computer modeling. Three cases are considered: a bare frame (Case 1), a frame with bracing in the middle bays (Case 2), and a frame with bracing at the corners (Case 3). Results show that Case 2 with middle bracing has the lowest time period, displacements, and drift, indicating it best resists earthquake forces by increasing the lateral stiffness of the frame. While the bare frame has the lowest base shear, the addition of bracing in Cases 2 and 3 significantly improves the seismic performance of the building.
Comparative Study of Seismic Analysis of Building with Light Weight and Conve...Dr. Amarjeet Singh
In recent decades, the lightweight materials are used
in construction instead of conventional material. Lightweight
construction is considered to be favourable due to the saving
in construction cost and materials. AAC block is a lightweight
structural material with excellent acoustic and thermal
insulation properties. Due to the use of lightweight material in
construction in seismic zone reduce the percentage of
damages. In this paper the attempt has been made to carry out
the project comparative study of seismic analysis of building
with lightweight and conventional material. Structural model
of multi storey building (G+3) and analysis is carried out in
STAAD-Pro by RSM (Response Spectrum Method). Building
using infill AAC (Autoclaved aerated concrete) block and
conventional clay brick masonry are designed for the same
seismic hazard in accordance with the applicable provisions
given in Indian codes. The analytical results of the buildings
will be compared. The project is also aimed at getting
familiarity with STAAD-Pro.2008.
This document provides a review of seismic isolation techniques for buildings. It summarizes the current practices of seismic isolation, describes common seismic isolation hardware including elastomeric bearings and sliding bearings, and chronicles the history of seismic isolation through shake table testing. The document also reviews past efforts to achieve three-dimensional seismic isolation and identifies areas where further research is needed, such as protecting nonstructural components from vertical ground motions and mitigating local uplift demands in isolation systems.
Seismic Vulnerability Assessment of Steel Moment Resisting Frame due to Infil...IDES Editor
Steel moment resisting frame with open first storey
(soft storey) is known to perform well compared with the RC
frames during strong earthquake shaking. The presence of
masonry infill wall influences the overall behavior of the
structure when subjected to lateral forces, when masonry infill
are considered to interact with their surrounding frames the
lateral stiffness and lateral load carrying capacity of structure
largely increase. In this paper, the seismic vulnerability of
building with soft storey is shown with an example of G+10
three dimensional (3D) steel frame. The open first storey is
an important functional requirement of almost all the urban
multi-storey buildings, and hence, cannot be eliminated.
Hence some special measures need to be adopted for this
specific situation. The under-lying principle of any solution
to this problem is in increasing the stiffness’s of the first
storey such that the first storey stiffness is at least 50% as
stiff as the second storey, i.e., soft first storeys are to be avoided,
and providing adequate lateral strength in the first storey. In
this paper, stiffness balancing is proposed between the first
and second storey of a steel moment resisting frame building
with open first storey and brick infills as described in models.
A simple example building is analyzed by modeling it with
nine different methods. The stiffness effect on the first storey
is demonstrated through the lateral displacement profile of
the building.
Seismic performance of weak base strong column steel moment framesSebastian Contreras
This document summarizes research on the seismic performance of steel moment frames with weak base connections and strong columns. The researchers analyzed a 4-story steel moment frame building using nonlinear time history analysis with different base connection strengths, including fixed, pinned, and varying hysteretic strengths from 1 to 0.3 times column strength. Results showed promise for weaker base connections but also issues like reduced base stiffness concentrating deformations in the first story. Future work is needed to further evaluate weak-base strong-column systems and address limitations.
“ Study of Sesmic Analysis of Masonry Wall Structure”IJERA Editor
Earthquakes are natural trouble under which disasters are mainly caused by damage or collapse of the structure and other man-made structures. When an earthquake occurs natural period of vibration is more on heavy loaded building and less in light loaded building. If the building is light weighted, i.e. steel is less then economy of structure is also achieved. Hence it is necessary to find out natural/fundamental time period when mass changes with different type of brick masonry and concrete masonry.This is necessary because IS 1893:2002 does not incorporate the effect of mass in a formula which they have mentioned for brick masonary structure. Thedesign will also analyze with ETAB software.
Finite ElementAnalysis of Doubly Curved Thin Concrete ShellsHARISH B A
thin shell is a “Three-dimensional spatial structure made up of one or more curved surfaces whose
thickness is small compared to their other dimensions”. Shells belong to the class of stressed skin structures which,
because of their geometry and small flexural rigidity of the skin, tend to carry loads primarily by direct stresses acting in
their plane. The shells are subjected to pure membrane state of stress, under appropriate loading and boundary
condition the resulting bending and twisting moments are either zero or small which may be neglected. The coordinates
of funicular shells are determined by masonry mould method by developing a computer program. In this study doubly
curved thin shells are analysed using finite element software SAP 2000. Doubly curved shells which are in square plan
having 10mX10m and 15mX15m are considered and shells in rectangular plan having dimensions 10mX15m
and 15mX20m are considered. The behavior of shells under self-weight, live load varying from 0-20KN/m (UDL) is
obtained. In this case study deflection curves, membrane stress and stress contour diagram are obtained. It is observed
that with the increase in rise and thickness of funicular shell the deflection are reduced. The membrane stresses
decreases with the increase in rise and thickness of concrete funicular shell. The aim of this study is to develop shells of
different sizes and investigation is done on the shells by finite element analysis under given uniformly distributed load,
to find out the behavior of shells in various cases using standard software, Structural Analysis Package (SAP 2000).
1. SOM's structural engineering studio develops sustainable structural solutions for tall buildings by drawing inspiration from natural forms and geometries found in nature. These biomimetic designs result in efficient, durable tower structures.
2. For projects like the China World Trade Center and Jinling Hotel Tower, SOM studied the growth patterns of bamboo and applied the efficient bracing and tapering to create tall structures that resist lateral loads.
3. Projects such as the Poly International Plaza and Transbay Tower use intricate grid structures and screen frames derived from hurricanes and nautilus shells to provide strength and allow for open floor plans with minimal material usage.
A Study on Seismic Response of Reinforced Concrete Framed Buildings with and ...IRJET Journal
This document presents a study on the seismic response of reinforced concrete framed buildings with and without infill walls. It analyzes two buildings, one with 5 stories and one with 9 stories, using different modeling techniques in SAP2000 software. The buildings are modeled as bare frames without infills, with single diagonal struts, double struts, and triple struts to represent the infill walls. Results for parameters like total weight, period, base shear, and modal participation are compared between the different models to understand the effect of including infill walls in the analysis. The goal is to evaluate how masonry infill walls contribute to the seismic resistance of reinforced concrete buildings.
The base isolation system is well-known as a sophisticated device for reducing
earthquake energy that a building structure is subjected to under earthquake impact.
Currently, many researchers are attempting to develop low-cost base isolation
intended for low-rise buildings by replacing steel reinforcement with an alternative
material. In this research project, the seismic response of residential housing units
that used perforated-reinforced elastomeric isolators (PREIs) within one- and twostory
reinforced concrete (RC), are investigated. The nonlinear dynamic analysis
(time history) considered seven ground motions to assess the seismic performance of
the structure under extreme earthquake shaking. The nonlinear dynamic analysis
method was developed to provide a more realistic model of structural response to
strong ground shaking. The lateral displacement, inter-story drift, base shear,
acceleration and overturning moment were analyzed to ensure that the low-rise
building behaved elastically under strong ground motion without any damage on both
nonstructural and structural components. The results illustrated that the application
of the isolators in the low-rise building was reliable in providing low horizontal
stiffness and a longer fundamental period. In addition, the study illustrated the
advantage of applying isolators in the upper structure, reducing base shear,
acceleration and drift ratio drastically. The large lateral displacement of the isolator
played an important role in the stability of the isolated structure. Therefore, special
attention must be paid in the design process of the isolator to guarantee suitable
response of the upper structure under strong earthquake shaking.
This document summarizes a research paper that aims to revive traditional earthquake resistant construction techniques in Kashmir, India by making them more cost effective and stronger. Specifically, it focuses on replacing timber with bamboo in the traditional "Dhajji Dewari" bracing system. The document provides background on Dhajji Dewari, its earthquake resistance properties. It then discusses how replacing timber with bamboo could make this technique more affordable and strong, as bamboo has various advantages over timber. Various models of Dhajji Dewari frames using timber and bamboo were tested and their costs and strengths were compared to identify the best configuration.
Highly Deformable Energy-Dissipating Reinforced Concrete Elements in Seismic ...IJERA Editor
Incorporating scrap tyre rubber particles as partial replacement for aggregates has been found to produce concrete with improved ductility, deformability and damping which are desired characteristics of a viable material for enhancing structural response to earthquake vibrations. An analytical study using Drain-2dX was carried out to investigate the response of 4-storey, 3-bay reinforced concrete frames on innovative rubberised concrete deformable foundation models to simulated earthquake scaled to 5 different peak ground accelerations. Stress-strain properties of 3-layers aramid fibre-reinforced polymer (FRP)-confinement for concrete incorporating waste rubber from scrap vehicle tyres were used to model the elements of this foundation models. With a partial decoupling of the superstructure from the direct earthquake force, the models showed up to 70% reduction in base shear, an improved overall q-factor of 7.1, and an estimated frame acceleration of 0.11g for an earthquake peak ground acceleration of 0.44g. This implies that a non-seismically designed reinforced concrete frame on the proposed rubberised concrete deformable foundation system would provide a simple, affordable and equally efficient alternative to the conventional and usually expensive earthquake resistant concrete frames. A supplementary Arrest System (SAS) was proposed to anchor the frame from the resulting soft storey at the rubberised concrete foundation. A further research is recommended for the design of concrete hinges with rubberised concrete as used in the model with the most impressive response
Seismic Analysis on Bare Frame, Infilled Frame and Soft Story RC Framed Build...IRJET Journal
This document analyzes the seismic behavior of reinforced concrete (RC) framed buildings with different configurations through computer modeling and simulation. It compares the seismic performance of a bare frame building, an infilled frame building where the spaces between columns and beams are filled with masonry, a building with an open ground floor ("soft story"), and a building with open ground and first floors. The analysis found that the infilled frame performed best, with the highest base shear, natural frequency, and lowest story drift and time period. The bare frame performed worst. The soft story and two-story open configurations performed better than the bare frame but worse than the infilled frame. Infilled frames are therefore most effective at resisting earthquake forces compared to other
Review study on performance of seismically tested repaired shear wallseSAT Publishing House
This document summarizes research on the performance of reinforced concrete shear walls that have been repaired after damage. It begins with an introduction to shear walls and their failure modes. The literature review then discusses the behavior of original shear walls as well as different repair techniques tested by other researchers, including conventional repair with new concrete, jacketing with steel plates or concrete, and use of fiber reinforced polymers. The document focuses on evaluating the strength retention of shear walls after being repaired with various methods.
Effect of Wire Mesh Orientation on Strength of Beams Retrofitted using Ferroc...CSCJournals
The document discusses an experimental study on the effect of wire mesh orientation in ferrocement jackets used to retrofit under-reinforced concrete beams. Eight prototype beams were tested, with two control beams and six beams stressed to 75% of the control capacity and then retrofitted. Ferrocement jackets with wire mesh at 0, 45, and 60 degrees were used. Testing found load capacity increased 45.87-52.29% for retrofitted beams. Beams with 45 degree wire mesh showed the highest increase in energy absorption, followed by 60 and 0 degrees. Ductility increased most for 0 degree wire mesh retrofitted beams. The 45 degree orientation provided the best balance of increased load capacity and energy absorption.
The document summarizes research on deriving fragility curves for traditional timber-framed masonry buildings in Lefkas, Greece using nonlinear static analysis. Key points:
- Traditional timber-framed masonry buildings in Lefkas have a "dual" structural system with stone masonry on the ground floor and a secondary timber post system to resist earthquake loads if the ground floor fails.
- Nonlinear static pushover analyses are used to develop pushover curves for the primary and secondary systems, which are then combined into a capacity curve to define damage states and derive fragility curves.
- Four damage states are defined: slight, moderate, heavy damage and collapse based on criteria related to
Modern strengthening strategies for steel moment resisting framesAlexander Decker
This document summarizes recent strengthening strategies for steel moment resisting frame connections. It discusses two main categories of strengthened connections: 1) Reinforced connections where a cover plate, haunch, or rib is added to strengthen the connection, and 2) Reduced beam section connections which locally weaken the beam away from the column. The document reviews studies on various reinforced connection details including haunched connections, welded/bolted cover and flange plates, proprietary side plates, and bolted bracket connections. Testing of these connection types found they improve seismic performance by distributing stresses away from the joint and increasing deformation capacity.
Seismic Analysis of Framed R.C. Structure with Base Isolation Technique using...ijtsrd
A Natural Calamity like an earthquake has taken a million lives throughout in our past. The force induced due to earthquake is dangerous and last for short duration of time. There are various techniques that can be used resist the force of an earthquake such as base isolation, bracing etc. The principle of base isolation is to isolate the structure from the motion of an earthquake and protect the structure and also reduce the force being transmitted to the building due to earthquake. For this study, G 13 storied R.C. frame building is considered and time history analysis is carried out using E Tabs 2017 software, and also study investigates structural behavior of multi story building with or without base isolation subjected earthquake ground motion. The Lead Rubber Bearing LRB is designed as per UBC 97 code and the same was used for the analysis of base isolation system. Here we shall studying earthquake resistivity of structure by analyzing the base isolation structure to compare its structural performance with fixed base isolation. Rohan G Raikar | Dr. Shivakumaraswamy | Dr. S Vijaya | M. K Darshan "Seismic Analysis of Framed R.C. Structure with Base Isolation Technique using E-Tabs" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-4 | Issue-5 , August 2020, URL: https://www.ijtsrd.com/papers/ijtsrd33166.pdf Paper Url :https://www.ijtsrd.com/engineering/civil-engineering/33166/seismic-analysis-of-framed-rc-structure-with-base-isolation-technique-using-etabs/rohan-g-raikar
Out of Plane Behavior of Contained Masonry Infilled Frames Subjected to Seism...paperpublications3
The document discusses the out-of-plane behavior of reinforced concrete (RC) frames with contained masonry infill subjected to seismic forces. It presents results from a finite element analysis of RC frames with different configurations: bare frames, frames with plain masonry infill, and frames with contained masonry infill wrapped in steel wires. The analysis determined the natural frequencies of the frames under different configurations and aspect ratios. It found that frames with contained masonry infill had the highest natural frequencies, followed by frames with plain masonry infill, with bare frames having the lowest natural frequencies.
IRJET- Seismic Response of Multi-Storey Building with Short Core Buckling...IRJET Journal
This document summarizes a study that analyzes the seismic response of multi-story buildings with different bracing systems, including short core buckling restrained braces (BRBs). 8- and 16-story building models were created with conventional bracing, long core BRBs, and short core BRBs. Non-linear time history analysis was performed and results were compared. Short core BRBs have a shorter steel core than conventional long core BRBs, which can impact energy dissipation. The study aims to provide more detailed behavior analysis of buildings with short core BRBs using different core materials.
Aij standard for structural design of reinforced concrete boxed shaped wall s...Putika Ashfar Khoiri
This document provides an overview and summary of the AIJ Standard for Structural Design of Reinforced Concrete Boxed-Shaped Wall Structures published by the Architectural Institute of Japan. The summary includes:
1) Reinforced concrete box-shaped wall structures are a common structural system used for residential apartment buildings in Japan, consisting of load-bearing walls, wall beams, slabs, and foundations.
2) The standard was developed based on experimental testing and the excellent seismic performance of these structures. No significant damage was observed in buildings meeting this standard even during major earthquakes.
3) The standard provides specifications for wall arrangement, thickness, reinforcement, and other structural details to ensure adequate strength and prevention of
This document summarizes shake table testing of a full-scale two-story wood-framed structure. The testing was conducted in 5 phases to study the impact of different structural elements on seismic behavior. Phase 1 tested the structure with only wood structural components. Phases 3-5 added interior gypsum wallboard and exterior stucco finishes. Natural period and stiffness were measured after each phase. Adding interior wallboard slightly reduced period while adding exterior stucco reduced period more significantly, increasing lateral stiffness by up to 32%. The testing provided data on how non-structural finishes affect the seismic performance of wood-framed buildings.
Seismic Evaluation of RC Building with Various Infill Thickness at Different ...IRJET Journal
This document summarizes research on evaluating the seismic performance of reinforced concrete buildings with masonry infill walls of various thicknesses in different positions. Previous studies have shown that infill walls can improve the strength, stiffness, and energy absorption of RC frames under seismic loads. However, infill walls are often not properly considered in structural design. This study aims to investigate how infill wall thickness and location affect seismic response parameters like moments, shear forces, displacements and drift. The results will help identify efficient building configurations to inform seismic design codes.
SEISMIC ISOLATION OF RC FRAMED STRUCTURE WITH AND WITHOUT INFILLSIAEME Publication
Earthquakes are the nature’s greatest hazard which cannot be exactly predicted by human
beings. Earthquake is a sudden movement of earth’s surface with the release of massive energy
in the form of seismic waves. There are so many methods to control the vibration of the
buildings like passive, active and hybrid control systems.[1] Base isolation is a passive control
system. In the present work, a (G+3) structure considering with and without infill’s subjected
to seismic force along with static gravity loads are analyzed using Response Spectrum Method
in ETABS-2015 package. From the study, the response of the structure obtained is time period,
base shear, story displacement and inter-story drifts and also the comparison is drawn for the
same parameters considering structure as bare and infill frames. The variation in percentage
of steel is also presented. It is found that the time period and story displacement increases
while base shear and story drifts gets reduces with the provision of effective base isolators.
IRJET- A Study on Seismic Performance of Reinforced Concrete Frame with L...IRJET Journal
This document presents a study on the seismic performance of a 10-storey reinforced concrete frame with different lateral force resistant systems, including a base isolation system using lead rubber bearings. Three models of the frame were analyzed: fixed base, braced with X-bracing, and base isolated. Time history, static, and pushover analyses were conducted. The results show that the base isolated frame performed best in reducing story drift, displacement, shear, and acceleration under seismic loading compared to the fixed base and braced frames. Maximum drift was 0.415mm for the base isolated frame versus 26.62mm for the fixed base frame. The base shear was also significantly reduced from 2294.3kN to 32.935
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
Applications of dampers for vibration control of structures an overvieweSAT Journals
Abstract
Dampers have become more popular recently for vibration control of structures, because of their safe, effective and economical
design. This paper presents an overview of literature related to the behavior of dampers on seismically affected structures. The review
includes different types of dampers like metallic dampers, viscoelastic dampers, frictional dampers etc.
Keywords: Seismic response, dampers, structural control systems.
Presentation in the Franhoufer IIS about my thesis: A wavelet transform based...Pedro Cerón Colás
Presentation in the Franhoufer IIS about my thesis: A wavelet transform based application for seismic waves. Analysis of the performance. Code made in Matlab.
Effect of damper on sesmic demand ond diffrent soil with help of staadPushkar Kokane
This document discusses seismic behavior of short period structures with diagonal dampers. It examines the relationship between force modification factor and global ductility demand for short period structures with dampers. Dampers with high damping ratios can keep structural response in the elastic range even for high force reductions. The document reviews several studies on the effect of dampers on seismic demand of short period structures founded on different soil types, including rock, soft soil, and deep cohesionless soil. The studies found that dampers can reduce ductility demand and bring short period structural behavior closer to that of long period structures. Seismic codes should account for differences between short and long period structures.
A Study on Seismic Response of Reinforced Concrete Framed Buildings with and ...IRJET Journal
This document presents a study on the seismic response of reinforced concrete framed buildings with and without infill walls. It analyzes two buildings, one with 5 stories and one with 9 stories, using different modeling techniques in SAP2000 software. The buildings are modeled as bare frames without infills, with single diagonal struts, double struts, and triple struts to represent the infill walls. Results for parameters like total weight, period, base shear, and modal participation are compared between the different models to understand the effect of including infill walls in the analysis. The goal is to evaluate how masonry infill walls contribute to the seismic resistance of reinforced concrete buildings.
The base isolation system is well-known as a sophisticated device for reducing
earthquake energy that a building structure is subjected to under earthquake impact.
Currently, many researchers are attempting to develop low-cost base isolation
intended for low-rise buildings by replacing steel reinforcement with an alternative
material. In this research project, the seismic response of residential housing units
that used perforated-reinforced elastomeric isolators (PREIs) within one- and twostory
reinforced concrete (RC), are investigated. The nonlinear dynamic analysis
(time history) considered seven ground motions to assess the seismic performance of
the structure under extreme earthquake shaking. The nonlinear dynamic analysis
method was developed to provide a more realistic model of structural response to
strong ground shaking. The lateral displacement, inter-story drift, base shear,
acceleration and overturning moment were analyzed to ensure that the low-rise
building behaved elastically under strong ground motion without any damage on both
nonstructural and structural components. The results illustrated that the application
of the isolators in the low-rise building was reliable in providing low horizontal
stiffness and a longer fundamental period. In addition, the study illustrated the
advantage of applying isolators in the upper structure, reducing base shear,
acceleration and drift ratio drastically. The large lateral displacement of the isolator
played an important role in the stability of the isolated structure. Therefore, special
attention must be paid in the design process of the isolator to guarantee suitable
response of the upper structure under strong earthquake shaking.
This document summarizes a research paper that aims to revive traditional earthquake resistant construction techniques in Kashmir, India by making them more cost effective and stronger. Specifically, it focuses on replacing timber with bamboo in the traditional "Dhajji Dewari" bracing system. The document provides background on Dhajji Dewari, its earthquake resistance properties. It then discusses how replacing timber with bamboo could make this technique more affordable and strong, as bamboo has various advantages over timber. Various models of Dhajji Dewari frames using timber and bamboo were tested and their costs and strengths were compared to identify the best configuration.
Highly Deformable Energy-Dissipating Reinforced Concrete Elements in Seismic ...IJERA Editor
Incorporating scrap tyre rubber particles as partial replacement for aggregates has been found to produce concrete with improved ductility, deformability and damping which are desired characteristics of a viable material for enhancing structural response to earthquake vibrations. An analytical study using Drain-2dX was carried out to investigate the response of 4-storey, 3-bay reinforced concrete frames on innovative rubberised concrete deformable foundation models to simulated earthquake scaled to 5 different peak ground accelerations. Stress-strain properties of 3-layers aramid fibre-reinforced polymer (FRP)-confinement for concrete incorporating waste rubber from scrap vehicle tyres were used to model the elements of this foundation models. With a partial decoupling of the superstructure from the direct earthquake force, the models showed up to 70% reduction in base shear, an improved overall q-factor of 7.1, and an estimated frame acceleration of 0.11g for an earthquake peak ground acceleration of 0.44g. This implies that a non-seismically designed reinforced concrete frame on the proposed rubberised concrete deformable foundation system would provide a simple, affordable and equally efficient alternative to the conventional and usually expensive earthquake resistant concrete frames. A supplementary Arrest System (SAS) was proposed to anchor the frame from the resulting soft storey at the rubberised concrete foundation. A further research is recommended for the design of concrete hinges with rubberised concrete as used in the model with the most impressive response
Seismic Analysis on Bare Frame, Infilled Frame and Soft Story RC Framed Build...IRJET Journal
This document analyzes the seismic behavior of reinforced concrete (RC) framed buildings with different configurations through computer modeling and simulation. It compares the seismic performance of a bare frame building, an infilled frame building where the spaces between columns and beams are filled with masonry, a building with an open ground floor ("soft story"), and a building with open ground and first floors. The analysis found that the infilled frame performed best, with the highest base shear, natural frequency, and lowest story drift and time period. The bare frame performed worst. The soft story and two-story open configurations performed better than the bare frame but worse than the infilled frame. Infilled frames are therefore most effective at resisting earthquake forces compared to other
Review study on performance of seismically tested repaired shear wallseSAT Publishing House
This document summarizes research on the performance of reinforced concrete shear walls that have been repaired after damage. It begins with an introduction to shear walls and their failure modes. The literature review then discusses the behavior of original shear walls as well as different repair techniques tested by other researchers, including conventional repair with new concrete, jacketing with steel plates or concrete, and use of fiber reinforced polymers. The document focuses on evaluating the strength retention of shear walls after being repaired with various methods.
Effect of Wire Mesh Orientation on Strength of Beams Retrofitted using Ferroc...CSCJournals
The document discusses an experimental study on the effect of wire mesh orientation in ferrocement jackets used to retrofit under-reinforced concrete beams. Eight prototype beams were tested, with two control beams and six beams stressed to 75% of the control capacity and then retrofitted. Ferrocement jackets with wire mesh at 0, 45, and 60 degrees were used. Testing found load capacity increased 45.87-52.29% for retrofitted beams. Beams with 45 degree wire mesh showed the highest increase in energy absorption, followed by 60 and 0 degrees. Ductility increased most for 0 degree wire mesh retrofitted beams. The 45 degree orientation provided the best balance of increased load capacity and energy absorption.
The document summarizes research on deriving fragility curves for traditional timber-framed masonry buildings in Lefkas, Greece using nonlinear static analysis. Key points:
- Traditional timber-framed masonry buildings in Lefkas have a "dual" structural system with stone masonry on the ground floor and a secondary timber post system to resist earthquake loads if the ground floor fails.
- Nonlinear static pushover analyses are used to develop pushover curves for the primary and secondary systems, which are then combined into a capacity curve to define damage states and derive fragility curves.
- Four damage states are defined: slight, moderate, heavy damage and collapse based on criteria related to
Modern strengthening strategies for steel moment resisting framesAlexander Decker
This document summarizes recent strengthening strategies for steel moment resisting frame connections. It discusses two main categories of strengthened connections: 1) Reinforced connections where a cover plate, haunch, or rib is added to strengthen the connection, and 2) Reduced beam section connections which locally weaken the beam away from the column. The document reviews studies on various reinforced connection details including haunched connections, welded/bolted cover and flange plates, proprietary side plates, and bolted bracket connections. Testing of these connection types found they improve seismic performance by distributing stresses away from the joint and increasing deformation capacity.
Seismic Analysis of Framed R.C. Structure with Base Isolation Technique using...ijtsrd
A Natural Calamity like an earthquake has taken a million lives throughout in our past. The force induced due to earthquake is dangerous and last for short duration of time. There are various techniques that can be used resist the force of an earthquake such as base isolation, bracing etc. The principle of base isolation is to isolate the structure from the motion of an earthquake and protect the structure and also reduce the force being transmitted to the building due to earthquake. For this study, G 13 storied R.C. frame building is considered and time history analysis is carried out using E Tabs 2017 software, and also study investigates structural behavior of multi story building with or without base isolation subjected earthquake ground motion. The Lead Rubber Bearing LRB is designed as per UBC 97 code and the same was used for the analysis of base isolation system. Here we shall studying earthquake resistivity of structure by analyzing the base isolation structure to compare its structural performance with fixed base isolation. Rohan G Raikar | Dr. Shivakumaraswamy | Dr. S Vijaya | M. K Darshan "Seismic Analysis of Framed R.C. Structure with Base Isolation Technique using E-Tabs" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-4 | Issue-5 , August 2020, URL: https://www.ijtsrd.com/papers/ijtsrd33166.pdf Paper Url :https://www.ijtsrd.com/engineering/civil-engineering/33166/seismic-analysis-of-framed-rc-structure-with-base-isolation-technique-using-etabs/rohan-g-raikar
Out of Plane Behavior of Contained Masonry Infilled Frames Subjected to Seism...paperpublications3
The document discusses the out-of-plane behavior of reinforced concrete (RC) frames with contained masonry infill subjected to seismic forces. It presents results from a finite element analysis of RC frames with different configurations: bare frames, frames with plain masonry infill, and frames with contained masonry infill wrapped in steel wires. The analysis determined the natural frequencies of the frames under different configurations and aspect ratios. It found that frames with contained masonry infill had the highest natural frequencies, followed by frames with plain masonry infill, with bare frames having the lowest natural frequencies.
IRJET- Seismic Response of Multi-Storey Building with Short Core Buckling...IRJET Journal
This document summarizes a study that analyzes the seismic response of multi-story buildings with different bracing systems, including short core buckling restrained braces (BRBs). 8- and 16-story building models were created with conventional bracing, long core BRBs, and short core BRBs. Non-linear time history analysis was performed and results were compared. Short core BRBs have a shorter steel core than conventional long core BRBs, which can impact energy dissipation. The study aims to provide more detailed behavior analysis of buildings with short core BRBs using different core materials.
Aij standard for structural design of reinforced concrete boxed shaped wall s...Putika Ashfar Khoiri
This document provides an overview and summary of the AIJ Standard for Structural Design of Reinforced Concrete Boxed-Shaped Wall Structures published by the Architectural Institute of Japan. The summary includes:
1) Reinforced concrete box-shaped wall structures are a common structural system used for residential apartment buildings in Japan, consisting of load-bearing walls, wall beams, slabs, and foundations.
2) The standard was developed based on experimental testing and the excellent seismic performance of these structures. No significant damage was observed in buildings meeting this standard even during major earthquakes.
3) The standard provides specifications for wall arrangement, thickness, reinforcement, and other structural details to ensure adequate strength and prevention of
This document summarizes shake table testing of a full-scale two-story wood-framed structure. The testing was conducted in 5 phases to study the impact of different structural elements on seismic behavior. Phase 1 tested the structure with only wood structural components. Phases 3-5 added interior gypsum wallboard and exterior stucco finishes. Natural period and stiffness were measured after each phase. Adding interior wallboard slightly reduced period while adding exterior stucco reduced period more significantly, increasing lateral stiffness by up to 32%. The testing provided data on how non-structural finishes affect the seismic performance of wood-framed buildings.
Seismic Evaluation of RC Building with Various Infill Thickness at Different ...IRJET Journal
This document summarizes research on evaluating the seismic performance of reinforced concrete buildings with masonry infill walls of various thicknesses in different positions. Previous studies have shown that infill walls can improve the strength, stiffness, and energy absorption of RC frames under seismic loads. However, infill walls are often not properly considered in structural design. This study aims to investigate how infill wall thickness and location affect seismic response parameters like moments, shear forces, displacements and drift. The results will help identify efficient building configurations to inform seismic design codes.
SEISMIC ISOLATION OF RC FRAMED STRUCTURE WITH AND WITHOUT INFILLSIAEME Publication
Earthquakes are the nature’s greatest hazard which cannot be exactly predicted by human
beings. Earthquake is a sudden movement of earth’s surface with the release of massive energy
in the form of seismic waves. There are so many methods to control the vibration of the
buildings like passive, active and hybrid control systems.[1] Base isolation is a passive control
system. In the present work, a (G+3) structure considering with and without infill’s subjected
to seismic force along with static gravity loads are analyzed using Response Spectrum Method
in ETABS-2015 package. From the study, the response of the structure obtained is time period,
base shear, story displacement and inter-story drifts and also the comparison is drawn for the
same parameters considering structure as bare and infill frames. The variation in percentage
of steel is also presented. It is found that the time period and story displacement increases
while base shear and story drifts gets reduces with the provision of effective base isolators.
IRJET- A Study on Seismic Performance of Reinforced Concrete Frame with L...IRJET Journal
This document presents a study on the seismic performance of a 10-storey reinforced concrete frame with different lateral force resistant systems, including a base isolation system using lead rubber bearings. Three models of the frame were analyzed: fixed base, braced with X-bracing, and base isolated. Time history, static, and pushover analyses were conducted. The results show that the base isolated frame performed best in reducing story drift, displacement, shear, and acceleration under seismic loading compared to the fixed base and braced frames. Maximum drift was 0.415mm for the base isolated frame versus 26.62mm for the fixed base frame. The base shear was also significantly reduced from 2294.3kN to 32.935
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
Applications of dampers for vibration control of structures an overvieweSAT Journals
Abstract
Dampers have become more popular recently for vibration control of structures, because of their safe, effective and economical
design. This paper presents an overview of literature related to the behavior of dampers on seismically affected structures. The review
includes different types of dampers like metallic dampers, viscoelastic dampers, frictional dampers etc.
Keywords: Seismic response, dampers, structural control systems.
Presentation in the Franhoufer IIS about my thesis: A wavelet transform based...Pedro Cerón Colás
Presentation in the Franhoufer IIS about my thesis: A wavelet transform based application for seismic waves. Analysis of the performance. Code made in Matlab.
Effect of damper on sesmic demand ond diffrent soil with help of staadPushkar Kokane
This document discusses seismic behavior of short period structures with diagonal dampers. It examines the relationship between force modification factor and global ductility demand for short period structures with dampers. Dampers with high damping ratios can keep structural response in the elastic range even for high force reductions. The document reviews several studies on the effect of dampers on seismic demand of short period structures founded on different soil types, including rock, soft soil, and deep cohesionless soil. The studies found that dampers can reduce ductility demand and bring short period structural behavior closer to that of long period structures. Seismic codes should account for differences between short and long period structures.
Seismic performance of structure with fixed base, base isolated structure and...eSAT Journals
Abstract Earthquakes can create serious damage to structures. The structures already built are vulnerable to future earthquakes. The damage to structures causes deaths, injuries, economic loss, and loss of functions. Damage to the structure causes due to ground acceleration. This can be minimizing by increasing strength of the structure. Sometimes it is not possible to increase the strength of the structure indefinitely. So it should be tried to increase the capacity of structure using seismic improvement techniques. In this study, there are three different types of G+10 structures with fixed base, structure with viscous damper and structure with high damping rubber bearing are considered. These structures are modeled using finite element software SAP2000v16. These structures have same plan area and are assumed to be situated in seismic zone IV and having medium soil condition. The analysis of these structures is done by performance based pushover analysis method and response spectrum method. The pushover analysis method is used to find out the performance point and capacity of structure. High damping rubber bearing isolators (HDRB) and viscous damper (VD) are use for seismic improvement of RC structure. The procedure of analysis adopted for fixed base structure is same repeated for structure with viscous damper (VD) and base isolated (HDRB) structure. So it will help in comparative parametric study. The results of analysis are compared in terms of storey displacements, modal time period, storey acceleration, performance point, storey drift. The comparative study shows that storey displacement, storey acceleration, storey drift is reduced substantially for structure with high damping rubber bearing (base isolated structure). Key Words: Base isolated structure, Pushover analysis method, Response spectrum method, Viscous damper, High damping rubber bearing, SAP2000v16 etc.
Seismic retrofitting modifies existing structures to increase their resistance to earthquakes. Common techniques include base isolators, which separate the structure from the ground using flexible bearings; supplementary dampers, which absorb and dissipate vibrational energy; tuned mass dampers, which reduce vibrations; and slosh tanks and active control systems, which also increase damping. The goal of retrofitting is to protect lives and ensure structural survivability, functionality, and integrity for historically significant buildings. Retrofitting techniques have evolved with new materials and provisions, helping structures withstand seismic impacts.
Seismic performance of adjacent building using fluid viscous dampersAyaz Malik
This presentation highlights the effect of Fluid Viscous Dampers (FVDs) on the seismic performance of adjacent buildings connected through a ped-way. A part of this project also deals with the Qualitative Damage Analysis of the structure during an earthquake, with and without FVDs.
Dampers Seismic Design – مخمدات الزلازل وانواعها في تخميد وتشتيت طاقة الزلازل Dr.Youssef Hammida
Seismic isolation is an important and effective method for rehabilitating buildings and roads to resist earthquakes. There are different types of seismic dampers according to their design and specifications. Seismic dampers do not prevent or stop earthquakes but soften their intensity by absorbing and dispersing earthquake energy to reduce distortions and deviations in buildings. Seismic dampers can be divided into three types: compression dampers that rely on compressible materials inside cylinders; friction dampers that operate between connecting elements; and flexible dampers that rely on compliant linking elements. The paper provides illustrations to further explain how these damper types absorb and disperse energy.
Earthquakes occur when tectonic forces cause rocks underground to break, releasing seismic waves. The focus is where the rocks break, and the epicenter is the point directly above on the surface. Different types of faults are caused by tension, compression, and shear forces. Earthquakes are measured by their magnitude using the Richter scale and by their intensity of shaking. Locating the epicenter involves measuring seismic wave arrival times at different stations. Earthquake dangers include falling objects, fires, tsunamis, liquefaction, and landslides.
Study on the effect of viscous dampers for RCC frame StructurePuneet Sajjan
1. The study analyzed the effect of adding viscous dampers to an 8-story reinforced concrete building modelled in ETABs software.
2. Dynamic analysis using response spectrum method showed that adding viscous dampers reduced displacement by up to 64%, story drift by up to 70%, and story shear by up to 30% compared to the model without dampers.
3. Viscous dampers work by dissipating energy through the flow of silicone-based fluid between piston-cylinder arrangements when the structure vibrates, reducing seismic loads on the building.
SEISMIC RESPONSE OF UNSYMMETRIC BUILDING WITH OPTIMALLY PLACED FRICTION DAMPERSIAEME Publication
Conventional methods of seismic rehabilitation with concrete shear walls or steel bracing
are not considered suitable for some buildings as upgrades with these methods would have
required expensive and time consuming foundation work. Supplemental damping in
conjunction with appropriate stiffness offers an innovative and attractive solution for the
seismic rehabilitation of such structures. This paper deals with the use of friction damper as a
passive dissipative device in order to seismic retrofit of existing structures and discusses the
optimal placement criteria. To fulfill this objective, six storey and ten storey L-shaped
buildings have been modeled with five different damper location formats in SAP2000 subjected
to El Centro and Utterkashi earthquake records. Non-Linear Modal Time History Method has
been used for the analysis and base shear, joint displacement, member forces and hysteresis
energy has been compared to find out most optimal damper location format.
Seismic waves are vibrations that travel through the Earth caused by earthquakes. There are three main types of seismic waves: primary (P-) waves, secondary (S-) waves, and surface waves. P-waves are the fastest waves and can travel through solid and liquid materials. S-waves are slower and only travel through solids. Surface waves are the slowest and only travel along the Earth's surface. These seismic waves transmit the energy and effects of earthquakes through the Earth.
Earthquake resistant building technologiesMyo Zin Aung
This document discusses various earthquake-resistant building technologies including:
1) Base isolation, which places structures on seismic bearings to isolate them from ground shaking.
2) Dampers like oil, viscous, and friction dampers that absorb seismic energy.
3) Tuned mass dampers and tuned liquid dampers that reduce vibrations through pendulums or liquid-filled tanks tuned to the building's natural frequency.
4) Innovations like yielding dampers, tuned mass dampers in skyscrapers, and "seismic invisibility cloaks" that deflect ground waves around structures.
SEISMIC PROTECTION OF RC FRAMES USING FRICTION DAMPERSIAEME Publication
The increasing infrastructural growth incurs large investments and large section of society
being served by them, it is necessary to make them safer against earthquakes and let people
feel confident in their structures. The need for structural response control has gained pace in
application around the globe. This paper discusses the use and effectiveness of one such
device, friction dampers, for response control of structures. In this paper a non-linear time
history analysis has been carried out on a 3D model of a 12 story RCC MRF building using 3-
directional synthetic accelerogram. Two different cases of building models with and without
friction dampers have been analyzed using ETABS. The response of the structure to seismic
excitation in terms of absolute maximum displacement and story drift has been compared.
Time history response plots have also been compared for various responses viz. roof
displacement and acceleration, base shear and story shear forces, along with the various
energy components and damping behavior. The results of the time history analysis are in close
conformation with previous investigations and represent the effectiveness of dampers in
improving the structural response as well as damping demand on structural systems.
This document introduces base isolation as a seismic retrofitting technique. It defines base isolation as decoupling a structure's superstructure from its substructure using structural elements. The document discusses the principle of base isolation, which is to isolate the structure from ground movement. It compares base isolation to other retrofitting techniques, noting advantages such as reduced structural damage and maintenance costs. The document also outlines different base isolation systems using elastomeric bearings and sliding systems. Examples of base isolation projects and companies utilizing the technique are provided. The document suggests government initiatives and training to develop base isolation in India.
Dampers are mechanical systems that dissipate earthquake energy by deforming or yielding. They absorb seismic energy, reducing forces on structures and controlling building oscillations. Common types include hydraulic dampers using fluid flow, electro-rheological fluid dampers using variable viscosity fluids, metallic dampers using hysteretic behavior of metals, steel dampers using frame deformation, and friction dampers using clamped friction surfaces. Shape memory alloys also dissipate energy through large strain recovery without damage. Dampers direct earthquake energy to dissipating devices within structures, transforming mechanical energy into heat.
Operaciones aritmeticas utilizando_radio_button(1)_1Giezy Vera
El documento describe los pasos para crear una aplicación Android básica que realiza sumas y restas. Se inicia un nuevo proyecto de aplicación Android, se le da un nombre y se elimina el texto predeterminado. Luego, se agregan widgets como text views, radio buttons y un botón para ingresar números, seleccionar una operación y mostrar el resultado. Finalmente, se agrega el código para realizar la operación seleccionada y mostrar el resultado en un text view.
Para ambientación. el laico y su compromiso en la nueva evangelizaciónAula Virtual
El documento habla sobre el papel de los laicos en la Iglesia. Define a los laicos como aquellos bautizados que no son clero y participan en las funciones de Cristo como sacerdotes, profetas y reyes. Explica que los laicos deben transformar el mundo desde adentro y ordenar las realidades temporales para establecer el Reino de Dios. También describe las misiones sacerdotal, profética y real de los laicos como participar en las funciones de Cristo a través de la ofrenda de sí mismos, anunciar el
Social Media Around Belgium (Presentation IAB Breakfast)Elias Veris
Social Media stats around Belgium, and why Belgium should be ashamed of itself.
A presentation given for the IAB breakfast.
For European/Worldwide results, check the core presentation at http://slidesha.re/p4CUAz .
This paper describes the structural design of the Carterton Events Centre in New Zealand, focusing on its seismic resistant system consisting of dissipative timber rocking post-tensioning walls. The auditorium features 11 of these 180mm thick LVL walls, each 6.7m tall and 2.4m long, with a central slot for post-tensioned bars. Energy dissipation is provided by embedded mild steel rods. Non-linear dynamic analysis confirmed the design, showing the walls concentrate damage at interfaces while self-centering to their original positions after seismic events.
Behaviour of reinforced concrete frame with in fill walls under seismic loads...IAEME Publication
This document summarizes a study on the behavior of reinforced concrete frames with masonry infill walls under seismic loads. Five models of a 10-story reinforced concrete building were analyzed using ETABS software: a bare frame, a fully infilled frame, and frames with different infill wall configurations. The results show that infill walls increase the lateral stiffness and strength of the frame, reducing displacements and member forces. However, openings in infill walls decrease stiffness. A higher Young's modulus for the infill material further increases stiffness. The analysis provides insights into how the structural response is affected by infill wall properties.
A review of the study of the fundamental natural time period of the AAC block...IRJET Journal
This document summarizes research on the fundamental natural time period of AAC block infill walls under seismic conditions. It first reviews previous literature that has studied how infill walls affect the behavior of reinforced concrete frames during earthquakes. The literature shows that infill walls increase structural stiffness and strength but reduce ductility. Studies also found that infill type does not significantly impact structural behavior. The document then outlines the objectives of infill walls in construction, such as dividing interior space, providing insulation, and enhancing fire resistance.
This document describes a 4-storey reinforced concrete test building with unreinforced masonry infill walls that will be used to test different seismic retrofit schemes. An analysis found the building has weak columns that are susceptible to sidesway collapse. The masonry infill provides much more shear strength than the bare concrete frame but at a smaller drift. Three retrofit schemes are proposed: 1) Replace masonry with damped bracing, 2) Jacket columns and some masonry with composite material to improve ductility, 3) Strengthen columns and add steel bracing. The effectiveness of each scheme will be tested using full-scale dynamic tests.
Comparison of Mesh Type Seismic Retrofitting for Masonry Structureschali090
The tremendous loss of life that resulted in the aftermath of recent earthquakes in developing countries is mostly due to the collapse of non-engineered building structures. It has been observed that these buildings cannot withstand the lateral loads imposed by an earthquake and often fails, in a brittle manner. This underscores the urgency to find simple and economic solutions to reinforce these buildings. Different conventional retrofitting techniques are available to increase the strength and/or ductility of unreinforced masonry walls. Recent years, several researches work on mesh type retrofitting for masonry structures to delay or prevent the collapse of buildings and reduce the number of lives lost during devastating earthquake events. This paper reviews and discusses the state-of-the-art on seismic retrofitting of masonry walls with emphasis on the mesh type retrofitting techniques include retrofitting procedures, cost, improvement in structural performance and limitations.
Application Of Smart Materials In Civil Engineering StructuresNat Rice
This document discusses the application of fiber reinforced plastics (FRP) for strengthening and retrofitting civil engineering structures. FRP composites have advantages like light weight, high strength, and ease of application. They have been used effectively to strengthen masonry, concrete, and reinforced concrete structures. Research shows that FRP wrapping or laminates can increase the load capacity and ductility of columns, walls, and other structural elements. Near surface mounted FRP bars have also been used successfully for flexural and shear strengthening of masonry walls. Experimental studies demonstrate that FRP retrofitting improves seismic performance by altering failure modes and maintaining structural integrity.
Lateral Load Analysis of Shear Wall and Concrete Braced Multi-Storeyed R.C Fr...ijsrd.com
Generally RC framed structures are designed without regards to structural action of masonry infill walls present. Masonry infill walls are widely used as partitions. These buildings are generally designed as framed structures without regard to structural action of masonry infill walls. They are considered as non- structural elements. RC frame building with open first storey is known as soft storey, which performs poorly during strong earthquake shaking. Past earthquakes are evident that collapses due to soft storeys are most often in RC buildings. In the soft storey, columns are severely stressed and unable to provide adequate shear resistance during the earthquake. . In this study, 3D analytical model of twelve storeyed buildings have been generated for different buildings Models and analyzed using structural analysis tool 'ETABS'. To study the effect of infill, ground soft, bare frame and models with ground soft having concrete core wall and shear walls and concrete bracings at different positions during earthquake; seismic analysis using both linear static, linear dynamic (response spectrum method) has been performed. The analytical model of the building includes all important components that influence the mass, strength, stiffness and deformability of the structure.
Lateral Load Analysis of Shear Wall and Concrete Braced Multi-Storeyed R.C Fr...ijsrd.com
This document analyzes the lateral load performance of different reinforced concrete frame models of a 12-story building using structural analysis software. Eight models are considered: a bare frame, fully infilled frame, frames infilled except the ground floor, and frames with shear walls, core walls or bracing in different configurations. Dynamic analysis shows fundamental periods are lowest for models with shear walls or bracing. Base shear and story drifts are highest for the bare frame and reduced by over 60% for infilled models. Models with ground soft-first story have increased drift, but shear walls or bracing can reduce drift by over 80% compared to the bare frame. Story displacements also decrease significantly with infilling or lateral load resisting elements.
This document contains questions and answers related to structural design principles. It discusses key concepts like robustness, strength, serviceability, stability, material properties, structural analysis, different load types, limit state design, and structural systems. Questions cover topics such as structural principles, material properties, stress-strain behavior, load considerations, deflection calculations, tributary areas, concrete beam design, reinforced and prestressed concrete, vibration causes and solutions, soil properties, retaining walls, ground improvement techniques, and foundation systems.
This summary provides an overview of the key structural concepts covered in the document:
1. The document discusses various structural principles including robustness, strength, serviceability, and stability and provides examples for each. It also defines material properties like ultimate stress and hardness.
2. Load types such as permanent loads, live loads, and wind loads are described along with considerations for determining their magnitude.
3. Limit state design and the two-layered factor of safety approach are explained. Limit state design uses modern methods to determine structural capacity and loading.
4. Stability systems like braced frames are discussed as ways to provide stability to structures subjected to lateral loads. The GLAD workflow for structural design is
LATERAL LOAD ANALYSIS OF SOFT STORY BUILDING AND IMPORTANCE OF MODELING MASON...ijsrd.com
Generally Masonry infills are considered as non-structural elements and their stiffness contributions are generally ignored in practice. But they affect both the structural and non-structural performance of the RC buildings during earthquakes. RC frame building with open first storey is known as soft storey, which performs poorly during strong earthquake shaking. A similar soft storey effect can occur if first and second story used as service story. Hence a combination of two structural system components i.e. Rigid frames and RC shear walls leads to a highly efficient system in which shear wall resist the majority of the lateral loads and the frame supports majority of the gravity loads. To study the effect of masonry infill with different soft storey level, 7 models of Reinforced Concrete framed building were analyzed with two types of shear wall when subjected to earthquake loading. The results of bare frame and other building models have been compared, it is observed that model with swastika and L shape shear wall are showing efficient performance and hence reducing the effect of soft storey in model 3, model 4 and model 5.
The document discusses various structural design principles and concepts including:
- Robustness, strength, serviceability, and stability as key structural principles.
- Defining ultimate stress and hardness as material properties.
- How materials behave after exceeding their yield strength on a stress-strain curve.
- Critical considerations for material selection like mechanical properties, wear resistance, and cost.
- Calculating axial tensile stress on a steel column given its dimensions and applied load.
- Engineer must consider member weights and load variations when determining dead and live loads.
- Limit state design uses a two-layered safety approach to determine load capacities.
Post tensioned concrete walls & frames for seismic resistanceĐỗ Hữu Linh
This case study describes the innovative use of post-tensioned concrete in the construction of the David Brower Center in Berkeley, California. The building uses a hybrid system of post-tensioned concrete walls and frames to provide improved seismic performance and self-centering behavior after earthquakes. This allows the building to avoid permanent damage and remain functional. The post-tensioning reduces the amount of conventional reinforcement needed, making the building more compact and efficient to construct while also lowering its carbon footprint through the use of slag cement. Non-linear simulations were used to verify the design of this unique structural system.
Review on Structural Performance of Braced Steel Sturtures Under Dynamic LoadingIRJET Journal
This document reviews the structural performance of braced steel structures under dynamic loading. It discusses three main types of bracings: eccentric braced frames, shape memory alloys, and buckling restrained braces. Eccentric braced frames provide energy dissipation and ductility through a ductile link. Shape memory alloys can regain their original shape after deformation and dissipate energy. Buckling restrained braces prevent buckling of steel braces under seismic loads through a composite action of a steel core encased in mortar. The document reviews various literature studying the seismic behavior and failures of these bracing systems.
Numerical Investigations on Blast Protection System with Metallic Tube Core S...IJLT EMAS
Effect of blast loads from explosion can be mitigated by using thick armor systems that are often heavy and significantly increase the self-weight of the structure. In the design of structure for blast protection, sacrificial claddings which consist of high energy absorbing elements are used. A sandwich type protective structure consists of light weight core which is often used for blast mitigation. The choice of core type has an influence on the performance of sandwich panel. The cores can be of wood, foam material and tubular elements. In this study, behavior of sandwich panel with square tubular core is investigated through numerical studies. Panel is made of mild steel having top plate dimension of 150 mm x 150 mm x 2.5 mm; bottom plate of 150 mm x 150 mm x 5 mm and square tube core of 12.5 mm x 12.5 mm with 0.6 mm thickness. A finite element model is developed and validated using experimental results in literature. Parametric studies are carried out using the validated finite element model. By varying the tube length of the core, the responses of the panels in terms of energy absorption and reaction forces are compared.
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
IRJET - Study on Lateral Structural System on Different Height on Asymmet...IRJET Journal
This document presents a study on using different lateral load resisting structural systems (shear walls and bracing) in asymmetric buildings of varying heights located in a high seismic zone. Finite element models of bare frame, shear wall, and braced configurations were created and analyzed using software. Placement of shear walls and bracing at the core or corners resulted in lower displacements and drifts compared to bare frames. Taller buildings benefited more from these lateral systems. Shear walls and bracing effectively resist earthquake forces and improve building performance.
This document summarizes a study analyzing the seismic response of a base isolated building frame compared to a fixed-base building frame. It first reviews previous literature on base isolation systems and their increasing use. It then describes modeling a reinforced concrete frame in SAP2000 software to conduct modal and time-history analyses. Modal analysis found the first natural frequency of the fixed frame. Time-history analysis used ground motion records from the 1994 Northridge earthquake to determine displacement, velocity, and acceleration responses in the frame. The study found lower responses in lower stories for the base isolated frame compared to the fixed frame.
This document summarizes research on retrofitting soft-story light frame timber buildings using a steel knee brace system called the Distributed Knee Brace (DKB) system. Full-scale testing of the DKB system confirmed it was able to support lateral loads beyond 6% drift while improving structural performance over previous wood-based versions. The steel DKB system provides a more predictable and optimized seismic retrofit solution compared to past designs using nailed wood connections.
Performance of shear wall building during seismic excitationsIAEME Publication
This document summarizes a study on the performance of shear wall buildings during seismic excitations. The study analyzed a 25-story building located in seismic zone 3, comparing the performance of two models: one with an L-shaped shear wall and one with a core-type shear wall. Time history analyses found that the building with the L-shaped wall experienced greater maximum displacement than the building with the core wall. Thus, providing shear walls as a core type can reduce story drift. Additionally, as the height of the building increases, shear walls absorb more lateral force than frames. Previous studies have also shown that shear walls with flanges perform better than walls without due to interaction between the flange and web.
Similar to 87 fluid dampers seismic-protection_woodframestruct (20)
1. Reference:
Symans, M.D., Cofer, W.F., Du, Y. and Fridley, K.J. (2001). “Fluid Dampers for Seismic Protection of Woodframe Structures,” Proc. of the
2001 Structures Congress and Exposition, ASCE, Edited by P.C. Chang, Washington, D.C., May, available on CD-ROM only.
1
Fluid Dampers for Seismic Protection of Woodframe Structures
Michael D. Symans1
, William F. Cofer2
, Ying Du3
, and Kenneth J. Fridley4
1. Assist. Professor; Dept. of Civil and Env. Engineering, Washington State University, Pullman,
WA 99164-2910; PH 509-335-5063; symans@wsu.edu
2. Assoc. Professor; Dept. of Civil and Env. Engineering, Washington State University, Pullman,
WA 99164-2910; PH 509-335-3232; wcofer@wsu.edu
3. Research Assist; Dept. of Civil and Env. Engineering, Washington State University, Pullman,
WA 99164-2910; ydu@wsu.edu
4. Professor; Dept. of Civil and Env. Engineering, Washington State University, Pullman, WA
99164-2910; PH 509-335-7320; fridley@wsu.edu
Abstract
In the recent past, a large number of steel-framed buildings have been constructed or retrofitted
with supplemental energy dissipation systems for the purpose of seismic protection. However,
the application of such systems to woodframe structures has been essentially non-existent except
for a limited number of experimental laboratory studies. This paper presents a numerical study
of the application of fluid dampers for seismic protection of wood-framed structures. Such
dampers dissipate energy via orificing of a fluid. The seismic response of a wood-framed shear
wall with and without dampers is evaluated via nonlinear finite element analyses. The results of
the analyses demonstrate that the dampers are capable of dissipating a large portion of the
seismic input energy while simultaneously relieving the inelastic energy dissipation demand on
the shear wall.
Introduction
Light-framed wood construction has generally been regarded as performing well during
moderate to strong earthquakes. Such performance is primarily due to the low mass of light-
framed construction combined with its ability to deform inelastically without inducing collapse
of the structure. Although light-framed wood structures typically do not collapse during
moderate to strong earthquakes, the inelastic response is generally associated with significant
structural and non-structural damage that may be very costly to repair. As an example of the
magnitude of the damage to light-framed wood buildings during a moderate earthquake, consider
the 1994 Northridge Earthquake (Moment Magnitude = 6.8) in which there was in excess of 20
billion dollars worth of damage to such structures (Kircher et al., 1997). Obviously, the 1994
Northridge Earthquake provides clear evidence that conventional light-framed wood buildings
are prone to significant damage when subjected to strong earthquake ground motions.
One approach to mitigating the effects of strong earthquakes on light-framed wood buildings is
to incorporate an advanced seismic protection system within the building. For example,
introducing a supplemental damping system within the framing of a building can reduce its
seismic response. The supplemental damping system dissipates a portion of the seismic input
energy, thereby reducing the amount of energy dissipated via inelastic behavior within the
structural framing. The number of applications of advanced seismic protection systems within
2. Reference:
Symans, M.D., Cofer, W.F., Du, Y. and Fridley, K.J. (2001). “Fluid Dampers for Seismic Protection of Woodframe Structures,” Proc. of the
2001 Structures Congress and Exposition, ASCE, Edited by P.C. Chang, Washington, D.C., May, available on CD-ROM only.
2
buildings has been steadily growing within approximately the past ten years. Nearly all of these
applications have been within either steel or concrete structures (e.g., see Soong and
Constantinou, 1995). There are a wide variety of supplemental damping systems available for
implementation in buildings (Constantinou et al., 1998 and Constantinou and Symans, 1993a).
However, the most rapid growth in the application of supplemental damping systems to buildings
has occurred for fluid dampers. Since the first experimental studies on a scale-model steel
building frame in 1993 (Symans and Constantinou, 1993b), the number of implementations of
fluid dampers within major bridge and building structures has grown to 49 with installation
pending in 17 additional structures. Although there are many factors that have contributed to this
rapid growth, one of the primary reasons is the high energy dissipation density of fluid dampers
(i.e., fluid dampers are capable of dissipating a large amount of energy relative to their size).
Relatively few studies have been conducted on the application of supplemental damping systems
for seismic protection of wood frame structures. Filiatrault (1990) performed a numerical study
to evaluate the seismic response of a woodframed shear wall with friction dampers at the corners
of the wall and Dinehart and Shenton (1998) and Dinehart et al. (1999) experimentally evaluated
the seismic response of a woodframed shear wall with viscoelastic dampers located at various
positions within the wall. The results of these studies clearly demonstrate that supplemental
damping systems have the potential for significantly improving the seismic response of wood-
framed buildings. Note that Symans et al. (2001) provides a comprehensive literature review on
the application of advanced seismic protection systems (both base isolation and supplemental
damping systems) to wood-framed structures.
To the knowledge of the authors, the research presented herein represents the first study on the
application of fluid dampers within wood-framed structures for seismic energy dissipation.
Description of Finite Element Model
A nonlinear finite element model of a wood-framed shear wall was developed for the numerical
analyses using the commercial program ABAQUS (ABAQUS, 1998) (see Figure 1). The
dimensions of the shear wall were 2.44 m x 2.44 m (8 ft x 8 ft). The framing of the wall
consisted of 38.1 mm x 88.9 mm (nominal 2 in. x 4 in.) lumber. The vertical studs were spaced
at 60.96 cm (24 in.) on center. The wall was sheathed with 1.22 m x 2.44 m (4 ft x 8 ft)
waferboard sheathing panels having a thickness of 9.53 mm (3/8 in.). The connections between
the sheathing and framing consisted of 6.35 cm (2.5 in.) 8d galvanized common nails. The field
and perimeter nail spacing was 15.24 cm (6 in.). The weight at the top of the wall was 44.5 kN
(10 kips), which is intended to represent the tributary weight if the wall were located at the first
story of a three-story building. The weight was distributed at the nodes along the top plate. The
bottom plate is assumed to be fixed to the foundation.
The framing members and sheathing panels were modeled as 2-D isoparametric beam elements
and 2-D isoparametric quadratic plane stress elements, respectively. The connection model for
each nail was based on the hybrid Stewart-Dolan connector model, as depicted by the hysteretic
loop shown in Figure 2. The parameters of the connection model were obtained from
experimental test data provided in Dolan (1989). Note that, as a simplification, the stiffness
degradation indicated in Figure 2 was not included in the analyses presented in this paper.
3. Reference:
Symans, M.D., Cofer, W.F., Du, Y. and Fridley, K.J. (2001). “Fluid Dampers for Seismic Protection of Woodframe Structures,” Proc. of the
2001 Structures Congress and Exposition, ASCE, Edited by P.C. Chang, Washington, D.C., May, available on CD-ROM only.
3
System identification of the wall model was performed via eigenvalue analysis wherein the
damping matrix of the wall (without dampers) was assembled using a Rayleigh damping
formulation. As obtained from the eigenvalue analysis, the natural frequency and damping ratio
in the fundamental mode were 4.18 Hz and 2.1%, respectively. The fundamental mode shape is
shown in Figure 3.
Figure 1 Finite Element Model of Wood-Framed Shear Wall.
Hybrid Stewart - Dolan Nail Connector Model
-1.5
-1.0
-0.5
0.0
0.5
1.0
1.5
-20 -15 -10 -5 0 5 10 15 20
Displacement (mm)
Load(kN)
Figure 2 Hysteretic Behavior of Nonlinear Connection Element.
4. Reference:
Symans, M.D., Cofer, W.F., Du, Y. and Fridley, K.J. (2001). “Fluid Dampers for Seismic Protection of Woodframe Structures,” Proc. of the
2001 Structures Congress and Exposition, ASCE, Edited by P.C. Chang, Washington, D.C., May, available on CD-ROM only.
4
Figure 3 Fundamental Mode Shape for Shear Wall.
Description and Configuration of Fluid Dampers
Fluid viscous dampers offer considerable promise for application within wood-framed buildings
due to their high energy dissipation density. The high energy dissipation density allows the
dampers to be conveniently located within the walls of a wood-framed structure. For example,
in this study, the damper was positioned along the diagonal of the wall (see Figure 4). In this
configuration, dual let-in rods are used to connect the lower corner of the wall to the end of the
damper. One rod is located on each side of the wall and small plates are used to prevent the rod
from buckling outward. One advantage to this configuration is that the damper force lies within
the plane of the wall and thus there are no bending moments applied to the wall at the corner
connections. In contrast, a disadvantage to this configuration is that the effectiveness of the
damper is reduced by 50% (for a square wall) due to the diagonal orientation.
In addition to their high energy dissipation density, the behavior of fluid dampers is quite unique
in that they are incapable of developing appreciable restoring forces for the frequencies of
motion expected during an earthquake (Symans and Constantinou, 1998). Thus, the dampers
behave essentially as pure energy dissipation devices. The design of structures that incorporate
such dampers becomes simplified since the dampers may be regarded as simply adding
additional energy dissipation capacity to the structure. Of course, one must recognize that the
installation of supplemental dampers will alter the load path for the transfer of forces within the
structure.
5. Reference:
Symans, M.D., Cofer, W.F., Du, Y. and Fridley, K.J. (2001). “Fluid Dampers for Seismic Protection of Woodframe Structures,” Proc. of the
2001 Structures Congress and Exposition, ASCE, Edited by P.C. Chang, Washington, D.C., May, available on CD-ROM only.
5
Piston Head
Piston Rod
Pinned Connection
Pinned
Connection
Viscous Fluid
Figure 4 Schematic of Fluid Damper and Orientation within Shear Wall.
Seismic Excitation
The mathematical model of the shear wall was subjected to the following earthquake ground
motions: 1) 1952 Kern County Earthquake, Taft record – Lincoln School Tunnel (S69E
component) and 2) 1994 Northridge Earthquake, Newhall record – LA County Fire Station (90o
component). These two records were selected since they are so disparate (i.e., the Taft record is
a weak, far-field motion while the Newhall record is a strong, near-field motion). The fluid
dampers proved to be beneficial for both types of ground motions. For the weak, far-field
motion, the structure remained essentially elastic with little to no permanent damage. For the
strong, near-field motion, the structure was damaged but much less so than without the dampers.
In this paper, results are presented for the near-field motion.
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
0 4 8 12 16 20 24 28 32
Time (sec)
Acceleration(g)
Figure 5 Ground Acceleration Record for Newhall Record (90o
comp.)
of 1994 Northridge Earthquake.
6. Reference:
Symans, M.D., Cofer, W.F., Du, Y. and Fridley, K.J. (2001). “Fluid Dampers for Seismic Protection of Woodframe Structures,” Proc. of the
2001 Structures Congress and Exposition, ASCE, Edited by P.C. Chang, Washington, D.C., May, available on CD-ROM only.
6
Results of Numerical Analysis
The analyses were performed for the shear wall alone and for the shear wall with one fluid
damper installed along the diagonal (see Figure 4). The damper was assumed to exhibit linear
viscous behavior with a damping coefficient of 87.6 kN-s/m (500 lb-s/in). Note that
experimental testing has shown that such damper behavior can be attained (e.g., see Symans and
Constantinou, 1998). The effectiveness of the damper is clearly depicted in the hysteresis loops
shown in Figure 6. Note that the two hysteresis loops are not plotted to the same scale on the
horizontal axis. For the wall alone (i.e., no damper), the hysteresis loop clearly demonstrates the
strongly nonlinear behavior of the wall. For the wall with the damper, the hysteresis loop
consists of a combination of damper behavior and wall behavior and thus it is not as readily
apparent how well the damper performed. However, a careful examination of the two loops
reveals that the peak drift was reduced by 87% when the damper was utilized. This represents a
significant reduction in structural damage. Furthermore, one may note the larger forces that
develop within the small displacement region of the pinching zone for the case of the wall with
the damper. This is the result of the damper force being proportional to velocity, thus leading to
large damper forces in the region of the pinching zone where the displacements are small and the
velocities are large. The larger forces that develop in the pinching region is one of the reasons
that the dampers are so effective.
Figure 6 Hysteresis Loops of Shear Wall Without and With Fluid Dampers.
The 87% reduction in peak drift may also be observed in the time-history shown in Figure 7.
The large pulse-like response that is often associated with strong, near-field ground motions is
readily apparent in the response for the wall with no damper. In contrast, the pulse-like response
is completely suppressed for the wall with the damper. In addition, Figure 7 shows that the peak
base shear increases by 37% for the wall with the damper. This is not surprising since the
inclusion of supplemental dampers in a building often leads to an increase in the peak base shear
(since the base shear has contributions from both the damper force and the wall shear force).
C = 87.6 kN-s/m
(500 lb-s/in)
No Damper
-0.8
-0.6
-0.4
-0.2
0.0
0.2
0.4
0.6
0.8
-6 -4 -2 0 2 4 6
Drift Ratio (%)
BaseShearCoefficient
-0.8
-0.6
-0.4
-0.2
0.0
0.2
0.4
0.6
0.8
-0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8
Drift Ratio (%)
BaseShearCoefficient
7. Reference:
Symans, M.D., Cofer, W.F., Du, Y. and Fridley, K.J. (2001). “Fluid Dampers for Seismic Protection of Woodframe Structures,” Proc. of the
2001 Structures Congress and Exposition, ASCE, Edited by P.C. Chang, Washington, D.C., May, available on CD-ROM only.
7
-1
-0.8
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
0.8
0 5 10 15
Time (sec)
BaseShearCoefficient
No Damper
C = 87.6 kN-s/m
-6
-5
-4
-3
-2
-1
0
1
2
3
4
0 5 10 15
Time (sec)
DriftRatio(%)
No Damper
C = 87.6 kN-s/m
Figure 7 Time-Histories of Drift Ratio and Base Shear Coefficient
The performance of the fluid dampers may also be evaluated by considering the energy
distribution within the wall during the earthquake. The time histories of various energy
quantities are shown in Figure 8 for the wall with and without the fluid damper. Note that the
two plots shown are plotted to the same scale. Figure 8(a) indicates that, without a fluid damper,
essentially all of the seismic input energy is eventually dissipated via inelastic behavior in the
wall. In contrast, Figure 8(b) demonstrates a significant reduction in energy dissipation demand
on the wall (i.e., the final inelastic energy demand is approx. 1 kN-m) while the viscous energy
dissipated by the fluid damper represents a large portion of the final seismic input energy
(approx. 2.7 kN-m). Thus, the fluid damper has effectively provided for a transfer of energy
dissipation demand from the wall to the damper. One may also note that the seismic input
energy is not the same for the wall with and without the damper. This is the case since the input
energy, as defined herein, is the integral of the base shear over the ground displacement. Since
the base shear is different for the wall with and without the damper, the input energy is also
different.
Practical Implementation Issues
For the wall with the damper, the force, velocity, and stroke demand for the damper are 14.8 kN
(3.3 kips), 17.0 cm/s (6.7 in/s), and 1.1 cm (0.43 in), respectively. Such characteristics are
readily available in off-the-shelf dampers. However, a number of issues remain to be addressed
before fluid dampers will find implementation in buildings. For example, it is recognized that
typical light wood-framed structures are primarily constructed in the field. To aid in the
installation of fluid dampers in such structures, it is likely that the damper would need to be
installed within a pre-fabricated shop-built wall that could be conveniently “dropped-in” to the
field-constructed walls. The pre-fabricated walls would be constructed in a controlled
manufacturing environment with damper connections that produce minimal slip prior to damper
engagement. Minimal slip will be important for controlling the level of damage during
earthquakes; particularly for frequent, weak earthquakes that, while producing damage in the
structure, generate relatively small wall displacements.
8. Reference:
Symans, M.D., Cofer, W.F., Du, Y. and Fridley, K.J. (2001). “Fluid Dampers for Seismic Protection of Woodframe Structures,” Proc. of the
2001 Structures Congress and Exposition, ASCE, Edited by P.C. Chang, Washington, D.C., May, available on CD-ROM only.
8
(a) (b)
Figure 8 Energy Distribution Within Wall During Earthquake.
Conclusions
Although there has been a steadily increasing growth in the application of supplemental energy
dissipation systems within steel structures, the applications within wood structures is essentially
non-existent. This is in spite of the fact that light-framed wood structures experienced extensive
damage during the 1994 Northridge Earthquake. The numerical analyses presented herein
represents the first study on the application of fluid dampers to light-framed wood buildings.
The results of the study offer convincing evidence of the potential benefit that fluid dampers
offer for seismic protection of light-framed wood structures.
Acknowledgments
This research was carried out under contract to California Universities for Research in
Earthquake Engineering (CUREe) as part of the CUREe-Caltech Woodframe Project
(“Earthquake Hazard Mitigation of Woodframe Construction”), under a grant administered by
the California Office of Emergency Services and funded by the Federal Emergency Management
Agency (FEMA). The authors are solely responsible for the information contained herein. No
liability for the information contained herein is assumed by California Universities for Research
in Earthquake Engineering, California Institute of Technology, California Office of Emergency
Services, or the Federal Emergency Management Agency.
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Systems for Structural Design and Retrofit, MCEER Monograph No. 1, Multidisciplinary Center
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Input
No Damper C = 87.6 kN-s/m
0
1
2
3
4
5
6
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Inelastic
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Input
Kinetic
0
1
2
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4
5
6
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Viscous
Input
KineticInelastic
Input
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Inelastic
9. Reference:
Symans, M.D., Cofer, W.F., Du, Y. and Fridley, K.J. (2001). “Fluid Dampers for Seismic Protection of Woodframe Structures,” Proc. of the
2001 Structures Congress and Exposition, ASCE, Edited by P.C. Chang, Washington, D.C., May, available on CD-ROM only.
9
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