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.
IRJET- Experimental Investigation on Seismic Retrofitting of RCC StructuresIRJET Journal
This document summarizes an experimental investigation into seismic retrofitting of reinforced concrete beam-column joints using concrete jacketing. The study tested control specimens designed to code standards and retrofitted specimens with concrete jackets added. The specimens were subjected to reverse cyclic loading to examine their performance and lateral load capacity. The concrete jackets were intended to improve seismic performance by increasing strength, stiffness, deformation capacity, and connection integrity of the joints. The results provide information on the behavior and effectiveness of reinforced concrete beam-columns strengthened with concrete jacketing under cyclic loading conditions.
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.
IRJET - Experimental Study on Performance of Buckling Restrained BracingsIRJET Journal
This document presents an experimental study on the performance of buckling restrained bracings (BRBs). BRBs are a type of seismic bracing that can yield in both tension and compression without buckling, providing stable energy dissipation. The study models five different BRB designs using finite element analysis to evaluate their hysteretic behavior and energy dissipation capacity when subjected to cyclic loading. The BRB designs vary the core plate shape and thickness, the material properties, and the gap size between the core and restraining tube. The goal is to identify the most efficient and economical BRB design that maximizes yield capacity and energy dissipation for seismic applications.
Study on Steel Beam Column Joint using Different Connections – State of ArtIRJET Journal
This document summarizes research on different types of steel beam-column connections, focusing on reduced beam section (RBS) connections. It discusses how RBS connections improve ductility by localizing plastic hinging in the reduced beam section, away from the connection. Several studies are summarized that experimentally and numerically analyze the behavior of RBS connections under cyclic loading, finding they provide excellent ductile performance by maintaining the elasticity of the connection region. Parameters like RBS geometry and profile are investigated. The document concludes RBS connections enhance seismic performance by preventing failure of connection components.
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.
Literature work study of precast concrete connections in seismicIAEME Publication
1. The document summarizes several studies on precast concrete connections, focusing on beam-column connections.
2. Key findings from the literature include that ductile connections can be designed to withstand seismic forces if connecting elements are used, and that hybrid post-tensioned and Dywidag Ductile connector systems have shown promise in seismic regions.
3. Finite element modeling studies found that accounting for shear transfer through vertical joints between precast wall panels provides more accurate force estimates than models neglecting this effect.
IRJET- Comparative Analysis of Square Shape RC Frame by Replacing Masonry fro...IRJET Journal
This document presents a comparative analysis of square shaped reinforced concrete frames with and without masonry infill using response spectrum analysis. Masonry infill walls are commonly used to fill gaps in RC frames but are often ignored in design. The study models an 8-story RC building in ETABS and replaces the masonry infill with an equivalent diagonal strut. Response spectrum analysis is performed for different relative stiffness levels by reducing the strut width by 5-50%. Parameters like time period, base shear, storey displacement and stiffness are compared. Results show infill increases stiffness and strength but displacement increases as strut width decreases. Infill frames generally perform better seismically than bare frames by reducing displacements and increasing stiffness
IRJET- Analysis of Various Effects on Multistory Building (G+27) by Staad Pro...IRJET Journal
This document analyzes the effects of shear walls on a 28-story building modelled in STAAD Pro software. Three models are considered: one without shear walls and two with shear walls in different locations (inward and outward parts of the building). The models are compared based on load transfer and lateral displacement of structural elements. Results show that providing shear walls in suitable locations significantly reduces displacements due to earthquake and wind loads. The document also reviews previous studies on shear wall behavior and modelling approaches. Methodology describes analyzing a 9-story building model with and without shear walls to determine optimal wall locations based on structural displacement and storey drifting.
IRJET- Experimental Investigation on Seismic Retrofitting of RCC StructuresIRJET Journal
This document summarizes an experimental investigation into seismic retrofitting of reinforced concrete beam-column joints using concrete jacketing. The study tested control specimens designed to code standards and retrofitted specimens with concrete jackets added. The specimens were subjected to reverse cyclic loading to examine their performance and lateral load capacity. The concrete jackets were intended to improve seismic performance by increasing strength, stiffness, deformation capacity, and connection integrity of the joints. The results provide information on the behavior and effectiveness of reinforced concrete beam-columns strengthened with concrete jacketing under cyclic loading conditions.
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.
IRJET - Experimental Study on Performance of Buckling Restrained BracingsIRJET Journal
This document presents an experimental study on the performance of buckling restrained bracings (BRBs). BRBs are a type of seismic bracing that can yield in both tension and compression without buckling, providing stable energy dissipation. The study models five different BRB designs using finite element analysis to evaluate their hysteretic behavior and energy dissipation capacity when subjected to cyclic loading. The BRB designs vary the core plate shape and thickness, the material properties, and the gap size between the core and restraining tube. The goal is to identify the most efficient and economical BRB design that maximizes yield capacity and energy dissipation for seismic applications.
Study on Steel Beam Column Joint using Different Connections – State of ArtIRJET Journal
This document summarizes research on different types of steel beam-column connections, focusing on reduced beam section (RBS) connections. It discusses how RBS connections improve ductility by localizing plastic hinging in the reduced beam section, away from the connection. Several studies are summarized that experimentally and numerically analyze the behavior of RBS connections under cyclic loading, finding they provide excellent ductile performance by maintaining the elasticity of the connection region. Parameters like RBS geometry and profile are investigated. The document concludes RBS connections enhance seismic performance by preventing failure of connection components.
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.
Literature work study of precast concrete connections in seismicIAEME Publication
1. The document summarizes several studies on precast concrete connections, focusing on beam-column connections.
2. Key findings from the literature include that ductile connections can be designed to withstand seismic forces if connecting elements are used, and that hybrid post-tensioned and Dywidag Ductile connector systems have shown promise in seismic regions.
3. Finite element modeling studies found that accounting for shear transfer through vertical joints between precast wall panels provides more accurate force estimates than models neglecting this effect.
IRJET- Comparative Analysis of Square Shape RC Frame by Replacing Masonry fro...IRJET Journal
This document presents a comparative analysis of square shaped reinforced concrete frames with and without masonry infill using response spectrum analysis. Masonry infill walls are commonly used to fill gaps in RC frames but are often ignored in design. The study models an 8-story RC building in ETABS and replaces the masonry infill with an equivalent diagonal strut. Response spectrum analysis is performed for different relative stiffness levels by reducing the strut width by 5-50%. Parameters like time period, base shear, storey displacement and stiffness are compared. Results show infill increases stiffness and strength but displacement increases as strut width decreases. Infill frames generally perform better seismically than bare frames by reducing displacements and increasing stiffness
IRJET- Analysis of Various Effects on Multistory Building (G+27) by Staad Pro...IRJET Journal
This document analyzes the effects of shear walls on a 28-story building modelled in STAAD Pro software. Three models are considered: one without shear walls and two with shear walls in different locations (inward and outward parts of the building). The models are compared based on load transfer and lateral displacement of structural elements. Results show that providing shear walls in suitable locations significantly reduces displacements due to earthquake and wind loads. The document also reviews previous studies on shear wall behavior and modelling approaches. Methodology describes analyzing a 9-story building model with and without shear walls to determine optimal wall locations based on structural displacement and storey drifting.
This document discusses the development of performance-based seismic design over the past 10 years, which emphasizes limiting structural damage based on deformation criteria rather than just strength. Three techniques for performance-based design are outlined: capacity spectrum method, N2 method, and direct displacement-based design. Factors defining different performance levels, like residual displacement, are discussed. Incorporating soil-structure interaction into performance-based design is also addressed.
Lateral Load Analysis of a Building with & Without Knee BracingIJERA Editor
In last decades steel structures has played an important role in construction industry. Providing strength, stability
and ductility are major purposes of seismic design. It is necessary to design a structure to perform well under
seismic loads. Steel braced frame is one of the structural systems used to resist earthquake loads in structures.
Steel bracing is economical, easy to erect, occupies less space and has flexibility to design for meeting the
required strength and stiffness. Bracing can be used as retrofit as well. There are various types of steel bracings
such as Diagonal, X, K, V, inverted V type or chevron and global type concentric bracings. In the present study,
it was shown that modelling of the G+4 steel bare frame with various bracings (X, V, inverted V, and Knee
bracing) by computer software SAP2000 and pushover analysis results are obtained. Comparison between the
seismic parameters such as base shear, roof displacement, time period, storey drift, performance point for steel
bare frame with different bracing patterns are studied. It is found that the X type of steel bracings significantly
contributes to the structural stiffness and reduces the maximum interstate drift of steel building than other
bracing systems.
IRJET- Comparative Study of Multi-Storey Building with Coupled Shear Wall...IRJET Journal
This document presents a comparative study of multi-storey buildings with conventional shear walls and coupled shear walls. It describes modeling 10, 20, and 30-story buildings of each wall type and analyzing them using response spectrum analysis and equivalent static analysis. The results, including storey displacements, drifts, shears, overturning moments, and stiffnesses, are compared. The conclusions show that coupled shear walls perform better than conventional shear walls in resisting seismic forces in tall buildings.
Seismic rehabilitation of beam column joint using gfrp sheets-2002Yara Mouna
The document summarizes a study that tested different rehabilitation techniques for improving the seismic performance of reinforced concrete beam-column joints. Three beam-column joints were tested: a control specimen and two specimens that were rehabilitated using glass fiber-reinforced polymer (GFRP) sheets. The control specimen failed in a brittle shear and bond failure mode, while the rehabilitated specimens exhibited a more ductile flexural failure of the beam. The rehabilitation techniques strengthened the joint shear capacity and prevented bond-slip failures of the beam reinforcement in the joint. A simple design methodology for the GFRP rehabilitation is proposed.
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.
Seismic study and performance of 30 storey high rise building with beam slab,...IRJET Journal
This document summarizes a study that compares the seismic performance of 30-story high-rise buildings with three different structural systems: conventional beam-slab, flat slab, and an alternate flat-beam slab system. Response spectrum analysis was used to model and analyze the buildings. The time periods, base shear, story shears, displacements, drifts, and column forces of each building were compared. The results showed that the beam-slab building performed better seismically, with lower drifts and accelerations compared to the flat slab building. The alternate flat-beam slab building performance was between the other two but closer to the beam-slab building. The flat slab building had significantly higher drifts and required columns
Numerical modeling on behaviour of reinforced concrete exterior beam column j...eSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
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.
1. The document discusses parameters that affect the strength of concrete in externally prestressed bridges. It examines factors like tendon layout, prestressing method, effective depth and eccentricity of external tendons, and materials used for tendons.
2. Studies have found that draped tendon profiles provide higher strength than straight profiles. External prestressing requires more prestressing force than internal prestressing, except for very deep girders. Increased effective depth and eccentricity of external tendons enhances strength.
3. Carbon fiber reinforced polymer tendons are an alternative to steel but have issues with brittleness and cost. Overall, optimizing tendon layout and placement can improve the strength of externally prestressed concrete bridges
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.
IRJET- Experimental Analysis of Buckling Restrained Brace Under Cyclic LoadngIRJET Journal
This document discusses the experimental analysis of buckling restrained braces (BRBs) under cyclic loading. BRBs are a type of bracing system used in structures to resist lateral forces like earthquakes. They have advantages over conventional bracing systems in providing a more stable hysteretic response. The study involved fabricating BRB models and testing them under static ultimate and cyclic loading. One model was tested to determine ultimate strength, while another was used to study behavioral characteristics under loading and unloading cycles. The results showed that BRBs can undergo considerable yielding in both tension and compression and dissipate more energy than conventional braces.
Beam column joints in concrete framed structure have been identified as critical member for transferring forces and bending moments between beams and columns. The change of moments in beam and columns across the joint region, under loadings, induces high shear force and stresses as compared with other adjacent members. The shear failure caused is often brittle in nature which is not an acceptable structural performance. Retrofitting enhances the moment carrying capacity of joint. Often beam column joints need to be strengthened. Author proposes use of ferrocement for retrofitting as wrapping technique, cost effective alternative to costly FRP wrapping technique. In this present research study, modelling & comparison of Beam-Column joint with and without ferrocement jacket is carried out by finite element method using software ANSYS APDL. The comparison shows enhanced performance of the jacketed model over Non jacketed in terms of stresses, ultimate load carrying capacity.
A Comparative Study for Seismic Performance of RC Moment Resisting Frame with...IOSR Journals
1) The document presents a comparative study of the seismic performance of reinforced concrete moment resisting frames using either steel reinforcement or fiber reinforced polymer (FRP) reinforcement.
2) Nonlinear static (pushover) analysis was used to evaluate the performance levels of structural members for buildings reinforced with steel bars and FRP bars.
3) The results found that frames reinforced with FRP bars exhibited significantly larger lateral displacements and slightly higher lateral strengths compared to frames with steel reinforcement, indicating improved seismic performance when using FRP bars.
IRJET-Cyclic Response of Perforated Beam in Steel Column JointsIRJET Journal
This document summarizes a study on the cyclic response of perforated steel beams in column joints under finite element analysis. The study analyzed the effect of various web opening parameters on the energy dissipation capacity of beams with circular and elongated circular openings. A finite element model was validated against experimental data and then used to conduct a parametric study. The study found that energy dissipation increased as opening size and dimensions increased, with maximum dissipation achieved when the opening depth was 80% of the beam depth. Openings with an elongated circular shape oriented across the beam depth also dissipated more energy than other orientations. In general, beams with larger perforations performed better in dissipating energy during cyclic loading.
IRJET- Behaviour of Castellated Beam with Coupled StiffenerIRJET Journal
1) The document discusses a study on the behavior of castellated beams with coupled stiffeners. A steel I-section beam is selected and analyzed using finite element analysis software.
2) Experimental testing is conducted on beams with two-point loading. The deflection at the beam center and various failure patterns are examined. The goal is to determine if load capacity increases or decreases with an optimized stiffener placed within hexagonal openings.
3) Previous research has looked at shear buckling behavior of web-posts, parametric studies of connections with circular openings, and using topology optimization to design perforated sections. Stiffeners are commonly used to strengthen plates and increase shear and moment resistance.
International Journal of Engineering and Science Invention (IJESI) inventionjournals
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- 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
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.
Buckling Restrained Braces (Brb) – A ReviewIRJET Journal
This document provides an overview of Buckling Restrained Braces (BRBs) as a lateral load resisting system for structures in seismic areas. It discusses how BRBs were developed to overcome the weaknesses of concentric bracing, which can buckle in compression. BRBs consist of a steel core encased in a concrete-filled tube with a coating to allow the core to slide without bonding. This restrains buckling and provides stable hysteretic behavior and energy dissipation in both tension and compression cycles. The document reviews the history, components, behavior, advantages and disadvantages of BRBs. It also summarizes several research papers that have studied innovative applications and testing of BRB systems.
A Review of “Seismic Response of RC Structures Having Plan and Vertical Irreg...IRJET Journal
This document summarizes and reviews a research paper on the seismic response of reinforced concrete (RC) structures with plan and vertical irregularities, with and without infill walls. It discusses how infill walls can improve or reduce the seismic performance of RC buildings, depending on factors like wall layout, height distribution, connection to the frame, and relative stiffness of walls and frames. The reviewed research paper analyzes the behavior of infill walls, effects of vertical irregularities, and seismic performance of high-rise structures under linear static and dynamic analysis. It studies response characteristics like story drift, deflection and shear. The document also provides literature on similar research investigating the effects of infill walls, soft stories, plan irregularities, and different
This study assessed the seismic performance of moment resisting steel frames (MRFs) and dual concentrically braced frames (D-CBFs) with four types of bolted beam-to-column connections in terms of strength and stiffness. Nonlinear static (pushover) and dynamic analyses accounting for joint behavior found that: 1) Frames with full strength and rigid or partial strength/rigid joints had higher behavior factors than frames assuming zero-length joints. 2) Nonlinear dynamic analysis showed global behavior of MRFs and D-CBFs with less influence of joint properties at the overall level. 3) Semi-rigid connections can be used without affecting overall response while reducing construction costs if deformability is accounted for in
A Study of R. C. C. Beam Column Junction Subjected To QuasiStatic (Monotonic)...IOSR Journals
This document summarizes a study on reinforced concrete beam-column junctions subjected to quasi-static (monotonic) loading. The study analyzes parameters like stress, displacement, and joint stiffness. Previous research on corner and exterior beam-column joints under cyclic loading is reviewed. The behavior of exterior joints differs from corner joints. Finite element analysis is used to model the joints, and results are compared to experimental data. Design and performance criteria for beam-column joints in seismic regions are discussed. Joint shear strength and bond strength are important factors addressed in the design process.
This document discusses the development of performance-based seismic design over the past 10 years, which emphasizes limiting structural damage based on deformation criteria rather than just strength. Three techniques for performance-based design are outlined: capacity spectrum method, N2 method, and direct displacement-based design. Factors defining different performance levels, like residual displacement, are discussed. Incorporating soil-structure interaction into performance-based design is also addressed.
Lateral Load Analysis of a Building with & Without Knee BracingIJERA Editor
In last decades steel structures has played an important role in construction industry. Providing strength, stability
and ductility are major purposes of seismic design. It is necessary to design a structure to perform well under
seismic loads. Steel braced frame is one of the structural systems used to resist earthquake loads in structures.
Steel bracing is economical, easy to erect, occupies less space and has flexibility to design for meeting the
required strength and stiffness. Bracing can be used as retrofit as well. There are various types of steel bracings
such as Diagonal, X, K, V, inverted V type or chevron and global type concentric bracings. In the present study,
it was shown that modelling of the G+4 steel bare frame with various bracings (X, V, inverted V, and Knee
bracing) by computer software SAP2000 and pushover analysis results are obtained. Comparison between the
seismic parameters such as base shear, roof displacement, time period, storey drift, performance point for steel
bare frame with different bracing patterns are studied. It is found that the X type of steel bracings significantly
contributes to the structural stiffness and reduces the maximum interstate drift of steel building than other
bracing systems.
IRJET- Comparative Study of Multi-Storey Building with Coupled Shear Wall...IRJET Journal
This document presents a comparative study of multi-storey buildings with conventional shear walls and coupled shear walls. It describes modeling 10, 20, and 30-story buildings of each wall type and analyzing them using response spectrum analysis and equivalent static analysis. The results, including storey displacements, drifts, shears, overturning moments, and stiffnesses, are compared. The conclusions show that coupled shear walls perform better than conventional shear walls in resisting seismic forces in tall buildings.
Seismic rehabilitation of beam column joint using gfrp sheets-2002Yara Mouna
The document summarizes a study that tested different rehabilitation techniques for improving the seismic performance of reinforced concrete beam-column joints. Three beam-column joints were tested: a control specimen and two specimens that were rehabilitated using glass fiber-reinforced polymer (GFRP) sheets. The control specimen failed in a brittle shear and bond failure mode, while the rehabilitated specimens exhibited a more ductile flexural failure of the beam. The rehabilitation techniques strengthened the joint shear capacity and prevented bond-slip failures of the beam reinforcement in the joint. A simple design methodology for the GFRP rehabilitation is proposed.
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.
Seismic study and performance of 30 storey high rise building with beam slab,...IRJET Journal
This document summarizes a study that compares the seismic performance of 30-story high-rise buildings with three different structural systems: conventional beam-slab, flat slab, and an alternate flat-beam slab system. Response spectrum analysis was used to model and analyze the buildings. The time periods, base shear, story shears, displacements, drifts, and column forces of each building were compared. The results showed that the beam-slab building performed better seismically, with lower drifts and accelerations compared to the flat slab building. The alternate flat-beam slab building performance was between the other two but closer to the beam-slab building. The flat slab building had significantly higher drifts and required columns
Numerical modeling on behaviour of reinforced concrete exterior beam column j...eSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
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.
1. The document discusses parameters that affect the strength of concrete in externally prestressed bridges. It examines factors like tendon layout, prestressing method, effective depth and eccentricity of external tendons, and materials used for tendons.
2. Studies have found that draped tendon profiles provide higher strength than straight profiles. External prestressing requires more prestressing force than internal prestressing, except for very deep girders. Increased effective depth and eccentricity of external tendons enhances strength.
3. Carbon fiber reinforced polymer tendons are an alternative to steel but have issues with brittleness and cost. Overall, optimizing tendon layout and placement can improve the strength of externally prestressed concrete bridges
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.
IRJET- Experimental Analysis of Buckling Restrained Brace Under Cyclic LoadngIRJET Journal
This document discusses the experimental analysis of buckling restrained braces (BRBs) under cyclic loading. BRBs are a type of bracing system used in structures to resist lateral forces like earthquakes. They have advantages over conventional bracing systems in providing a more stable hysteretic response. The study involved fabricating BRB models and testing them under static ultimate and cyclic loading. One model was tested to determine ultimate strength, while another was used to study behavioral characteristics under loading and unloading cycles. The results showed that BRBs can undergo considerable yielding in both tension and compression and dissipate more energy than conventional braces.
Beam column joints in concrete framed structure have been identified as critical member for transferring forces and bending moments between beams and columns. The change of moments in beam and columns across the joint region, under loadings, induces high shear force and stresses as compared with other adjacent members. The shear failure caused is often brittle in nature which is not an acceptable structural performance. Retrofitting enhances the moment carrying capacity of joint. Often beam column joints need to be strengthened. Author proposes use of ferrocement for retrofitting as wrapping technique, cost effective alternative to costly FRP wrapping technique. In this present research study, modelling & comparison of Beam-Column joint with and without ferrocement jacket is carried out by finite element method using software ANSYS APDL. The comparison shows enhanced performance of the jacketed model over Non jacketed in terms of stresses, ultimate load carrying capacity.
A Comparative Study for Seismic Performance of RC Moment Resisting Frame with...IOSR Journals
1) The document presents a comparative study of the seismic performance of reinforced concrete moment resisting frames using either steel reinforcement or fiber reinforced polymer (FRP) reinforcement.
2) Nonlinear static (pushover) analysis was used to evaluate the performance levels of structural members for buildings reinforced with steel bars and FRP bars.
3) The results found that frames reinforced with FRP bars exhibited significantly larger lateral displacements and slightly higher lateral strengths compared to frames with steel reinforcement, indicating improved seismic performance when using FRP bars.
IRJET-Cyclic Response of Perforated Beam in Steel Column JointsIRJET Journal
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Seismic performance of weak base strong column steel moment frames
1. 16th
World Conference on Earthquake Engineering, 16WCEE 2017
Santiago Chile, January 9th to 13th 2017
Paper N° 293
Registration Code: S-G1464738152
SEISMIC PERFORMANCE OF WEAK-BASE STRONG COLUMN STEEL
MOMENT FRAMES
MS. Valerio Castelo(1)
, P. Torres Rodas(2)
, F. Zareian(3)
, A. Kanvinde(4)
(1)
Alumni, Imperial College, London, marcello.valerio-castelo11@alumni.imperial.ac.uk
(2)
Ph.D. Candidate, University of California, Irvine, ptorres@uci.edu
(3)
Associate Professor, University of California, Irvine, zareian@uci.edu
(4)
Professor, University of California, Davis, kanvinde@ucdavis.edu
Abstract
Steel moment frames in seismically active regions are designed as strong-base weak-column systems, such that yielding is
concentrated in the lower region of the column member, thereby protecting the base connection itself. This is achieved
through capacity design of the base connection. This necessitates an expensive base connection, since heavy detailing is
required to develop the forces associated with column yielding. However, recent research by the authors and others has
shown that column base connections may be highly ductile with excellent dissipative characteristics. The research explores
the possibility of a weak-base system that leverages these characteristics. The study is conducted in a Performance Based
Earthquake Engineering (PBEE) framework, by examining the effect of base strength on various performance metrics –
including probabilities of collapse, and of exceeding critical member forces and interstory drifts. The results indicate
promise for these types of systems, but also highlight issues, which arise due to reduce base stiffness that accompanies the
weaker base. Limitations of the study are discussed along with directions for future work.
Keywords: Baseplates; Column base connection; Performance-based design; Seismic demand assessment
2. 16th
World Conference on Earthquake Engineering, 16WCEE 2017
Santiago Chile, January 9th to 13th 2017
SEISMIC PERFORMANCE OF WEAK-BASE STRONG COLUMN STEEL
MOMENT FRAMES
1. Introduction
The basic intent of building code seismic provisions is to provide buildings with the ability to withstand intense
ground shaking without collapse, however, some significant structural damage is allowed. In order to accomplish
this, the basic principle is to encourage the use of building configuration, structural system and material, and
component detailing for a global resilient behavior. Within this setting, Steel Moment Resistant Frames
(SMRFs) are one of the most common and popular lateral load resistant systems used in seismic regions due to
their architectural versatility and energy dissipative properties. In low- to mid-rise SMRFs, Exposed Column
Base (ECB) connections are often used to connect the steel column to the concrete foundation. These
connections are used in gravity frames to resist axial tension or compression, and in moment frames to resist
flexure and shear, along with axial force. In essence, this necessitates an expensive base connection since heavy
detailing is required to develop the forces associated with column yielding. In the current design practice, ECB
connections are designed to resist the maximum capacity of the attached columns (i.e. 1.1RyMp), based on the
capacity design principle, implying a “strong base weak column design”. This approach leads to the
development of the full flexural capacity of the columns and ultimately to the formation of plastic hinges on
them, with the presumption that a plastic hinge within the member will have higher rotation capacity. However,
experimental data curated by Lignos and Krawinkler (2007) [1] disaffirms this, suggesting that the ductility of
plastic hinges in columns may be compromised by phenomena such as local or lateral torsional buckling. In
large measure, the reliance on strong bases may be attributed to: (1) the general notion that connections are less
ductile than members, and (2) the lack of system simulation or testing that demonstrates acceptable performance
with weak-base systems.
Numerous experimental and analytical studies have been conducted on ECB connections to establish their
strength, stiffness, deformation capacity, and failure modes. Experimental studies by DeWolf and Sarisley, 1980
[2]; Astaneh et al., 1992 [3]; Burda and Itani, 1999 [4]; Fahmy et al., 1999 [5], and more recently Gomez et al.,
2010 [6], and Kanvinde et al., 2014 [7], have resulted in quantitative understanding of various aspects of ECB
response. These experimental investigations have demonstrated that if properly designed and detailed, ECB
connections can provide an inelastic rotation capacity in the range of 0.1 radians. Also, these tests revealed that
along with this significant rotation capacity, base connections themselves are able to substantially dissipate
hysteretic energy. These experiments (along with analytical models) suggest that even if designed as strong
bases, ECB connections exhibit significant flexibility. However, in terms of computational modelling they are
typically simulated as fixed, resulting in unrealistically optimistic estimates of building response in terms of
member forces, story drifts, and the likelihood of collapse. More specifically, rotational flexibility of ECB
connections concentrates deformations in the first story of the building, greatly diminishing ductility compared
to the design assumption [8].
The current design methods disregard the excellent dissipative features of ECB connections, leading to an
increase in the price of fabricating them. The experimental results obtained from tests revealed that the approach
of designing the base connections as yielding elements is promising and would lead to desirable economic
savings and to a more accurate characterization of the building response. Motivated by the preceding discussion,
the main objective of this paper is to contribute to the characterization and validation of a methodology for the
design of SMRFs with “weak-bases strong-column”. For this purpose, the study investigate the seismic
performance of a four story building with exposed base connections with respect to the variation in their
strength. This kind of connection is the most common form of anchoring system for low and mid-rise buildings,
including commercial, residential and industrial structures. Thus, the analysis of this type of base connection
enables the general characterization of the proposed approach for numerous and common building structures.
The four story building was selected to be a general representation of a low or mid-rise building. Also, four
stories would generally be the limiting height for the use of exposed connections.
2
3. 16th
World Conference on Earthquake Engineering, 16WCEE 2017
Santiago Chile, January 9th to 13th 2017
The description of the seismic performance of the structure was primarily accomplished by means of
Multiple Stripes Analysis (MSA). As described by Jalayer and Cornell (2009) [9], this nonlinear analysis
procedure enables performance studies to test numerous performance targets, including collapse prediction, for a
wide variety of ground motions. The ground motion records used to support the MSA in this investigation are
selected from the Applied Technology Council’s ATC-63 project (FEMA 2009) [10]. In total, 32 ground
motions were used, only including far-field records. In order to evaluate the effect of base strength in the
framework of Performance based Earthquake Engineering (PBEE), five connection strength levels were
investigated. They include a fixed connection, which would represent the assumption taken by the current design
codes for a building as such; a Pinned connection, and three connections whose response is characterized in
terms of a hysteretic model and which vary their strengths from one, representing a connection designed to the
capacity of the attached column, to 0.5 and 0.3 times the former.
2. Background
In the context of earthquake engineering, SMRFs are designed to resist earthquake ground shaking based on the
assumption that they are capable of extensive yielding and plastic deformation without extensive deterioration.
The intended plastic deformation consists of plastic rotations developed within the beams, at their connections to
the columns. Damage is expected to consist of moderate yielding and localized buckling of the steel elements.
SMRFs are anticipated to develop their ductility through the development of yielding at the beam column
connections. This yielding may take the form of plastic hinging in the beams (or, less desirably, in the columns),
plastic shear deformation in the column panel zones, or through a combination of these mechanisms. Beam to
column connections used in SMRFs shall be capable of accommodating a story drift angle of at least 0.04 rad.
Regarding to column base connections, current design provisions (i.e. Seismic Provisions AISC 341-10, 2010
[11]) encourage a designed based on a “strong-base weak-column criteria”, such that yielding is concentrated in
the lower region of the column member, thereby protecting the base connection itself. Taking this into
consideration, failure of the base connections should rarely occur. However, and as pointed out by Aviram et al.
(2010) [12], ECB connection failures have been observed in a large number of SMRFs during the 1989 Loma
Prieta, 1994 Northridge and 1995 Kobe Earthquakes. Motivated by these unexpected failures, many studies have
been targeted to investigate the effect that the mechanical properties of ECB connections cause on building
response and performance.
The response of ECB connections is determined by a complex interaction between its parts. These include
contact and gapping between the plate and the grout, yielding of the bolts, crushing of the grout and yielding of
the plate itself. The axial forces are transmitted directly to the base plate through the entire/effective cross
sectional area of the column. The lateral forces on to which the building could be subjected would create
differential stress profiles under the base plates depending on variables such as plate thickness or the relative
stiffness between the plate and the supporting material [13]. Primarily, the studies conducted on ECB
connections have focused on identifying strength limit states of these connections and providing approaches for
characterizing the strength of base connections culminating in the development of design guidelines such as the
American Institute of Steel Construction’s (AISC’s) Design Guide 1 [14]. The current design approach (AISC
Steel Design Guide One) assumes that the stress bulb takes the form of a rectangular block. It is important as
well to describe the failure modes that this kind of connections may exhibit. Gomez et al. (2010) [6] define three
common failure modes assumed in design. They are: (1) anchor rod yielding in tension due to uplift of the plate;
(2) the base plate reaches its tensile capacity due to the forces exerted by the anchor rods pulling; and (3)
yielding due to the bending produced by the bearing stresses between the plate and the concrete.
A comprehensive method for determining the rotational stiffness of ECB connections was proposed by
Kanvinde et al. (2012) [15]. This methodology allows to account in simulations for the dissipative properties that
base connections possess. The method is derived from existing design procedures in order to simplify the
calculation of the rotational stiffness. The method consist basically in three steps: 1) Characterization of design
strength ( yM ) of the connection in accordance with current design procedures. 2) Characterization of
deformation of individual components on the basis of internal force distribution, and 3) Enforcement of
compatibility over the various components to determine connection rotation at the applied base moment. Its
3
4. 16th
World Conference on Earthquake Engineering, 16WCEE 2017
Santiago Chile, January 9th to 13th 2017
accuracy depends on the moment to axial load ratio applied, being particularly accurate for high ratios and
overestimating for low ratios. This approach enabled the possibility of investigating the seismic response of
buildings with respect to base stiffness. Zareian and Kanvinde [8] studied this particular effect through a series
of parametric sophisticated simulations for a wide arrange of structures noting that overestimating the fixity of
base connections (or simulating the base connections as fixed) results in significant detriment to building
performance, including increased interstory drift and collapse probability. Consequently, the characterization of
the flexibility of the connections is critical to predict its effectiveness, and their influence in SMRF at a global
level. Thus, it serves as a starting point to begin evaluating the influence of variation in strength of the ECB
connections with respect to probability of collapse of the building.
3. Design and Description of Archetype Frames
For the purposes of this study, a four story building with ECB connection was selected, considering that it is
representative of a low or mid-rise building. The strength of the ECB connection was the main parameter varied.
Five connection strength levels were investigated. They include the two extreme cases, i.e. fixed and pinned
conditions, and three connections whose response is characterized in terms of a hysteretic model and which vary
their strengths from one, representing a connection designed to the capacity of the attached column, to 0.5 and
0.3 times the former. Figure 1 schematically illustrates the SMRF examined in this paper.
Referring to Figure 1, the SMRF has four bays, resist all the seismic design loads, and receive a tributary
gravity loads as indicated in the shaded portion of the plan view. The building has plan dimensions of 120ft by
180ft, respectively. The SMRF are located in the perimeter of the building on the short side (this being the
analyzed direction). The bay width is 30ft, and the height of the stories is 13ft. A uniform load of 83psf is
applied over each floor. An unreduced live load of 50psf is applied on all floors, whereas 20psf is applied on the
roof. All beam to column connections are designed as reduced beam sections (RBS) connections in accordance
with the Seismic Provisions (AISC, 2010) [11]. In terms of design, this affects column sizing due to strong
column – weak girder requirement. Table 1 summarizes the design results.
Table 1: Section Sizes
Floor Exterior Columns Interior Columns Beams
1 W14x342 W14x426 W30x148
2 W14x342 W14x426 W30x148
3 W14x257 W14x342 W30x148
4 W14x257 W14x342 W27x94
In order to have a comprehensive understanding of how the seismic performance of the structure would
vary with respect to the change in base strength, five strength levels were defined for the analyses. The first
level, i.e. fixed connection, corresponds to the assumption taken in the current design practice when modelling
the connections as fixities. The inclusion of this class is important as it will enlighten the difference that exist
between this widely used assumption and the real behavior of buildings. Then, three levels characterized by a
phenomenological rotational spring with pinching deterioration characteristics are included. The first of this,
level S1, is characterised by the stiffness and yield moment calculated as per IBC SEAOC Structural/Seismic
Design Manual [13]. This is a representation of a connection designed according to the current practice
specifications. This means that the yield moment is calculated to the capacity of the attached column. The
subsequent three levels are expressed in terms of a yield moment ratio with respect to S1. This levels are
therefore denominated S0.5 and S0.3, with the factor representing the strength of this connections with respect to
the designed to current codes. This classes will capture the real behavior of the column bases as designed and
also the effect of reducing their strength in order to set them as yielding elements and take advantage of their
excellent dissipative properties. Note that in all this four levels the stiffness is kept constant to the one calculated
to S1. Finally, a last class corresponding to a pinned connection is defined. The different values for the elastic
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rotational stiffness and yield capacity of all the six connection levels are summarized in the Table 2. These
stiffness assumptions imply distinctive characteristic not only in the building response but also in its dynamic
properties, specifically in terms of its ductility and natural period. Table 3 summarizes the properties of the
building corresponding at each strength level.
Table 2: Connection Strength Levels
Properties Fix
ρ = ∞
S1
1ρ =
S0.5
0.5ρ =
S0.3
0.3ρ =
Pin
0ρ ≈
Kext [kip-in]x106
∞ 1.38 1.38 1.38 0.0009
Kint [kip-in]x106
∞ 2.76 2.76 2.76 0.0009
My ext [kip-in]x104
∞ 44.72 22.36 13.42 0.027
My int [kip-in]x104
∞ 57.83 28.92 17.35
Table 3: Natural Periods and Spectral Acceleration
Base Connection Type First Mode Period
T1 [sec]
Spectral Acceleration
Sa(T1,5%)[g]
Fixed 0.93 0.76
Strength level 1 1.05 0.65
Strength level 0.5 1.05 0.65
Strength level 0.3 1.05 0.65
Pinned 1.28 0.55
4. Nonlinear Simulation of the Building
The frame is modeled as plane frame. The column bases are modeled with rotational spring with pinching
behavior with varying degrees of stiffness [16]. Table 2 introduced in the previous section summarizes the
different levels of stiffness considered. The rest of the frame is modeled to effectively capture geometric and
material nonlinearity. The software program OpenSEES [17] is used for all simulations. The beams and columns
were implemented by means of non-linear beam column (force based) elements. The beam and column sections
were included on the OpenSEES model using Fiber Sections [18]. Fiber Sections are sub-divided in patched,
which constitute a sub-region of a part of the section with regular shape and that contains a uniaxial material
which sets Bernoulli beam considerations. For this model and indicated by Shaw (2010) [18], each beam and
column sections were modelled by dividing them into three areas, the two flanges and the web, and assigning to
them a patch configuration of 16 by 4. Other assumed modeling conditions included were the enforcement of a
Rigid Diaphragm on each floor, the inclusion of Reduced Beam Sections (RBS) and the modelling of rigid link
zones in the beam to column connections. The Rigid Diaphragm was imposed by fixing the lateral displacements
of all nodes on the same floor to be the same. The inclusion of the RBS, close to the beam column connections,
ensured that the location in which plastic hinge formed on the beams was controlled, thus complying with the
real design characteristics of the building (Shaw 2010). The beam and column sections in the intersection joints
were modelled as Rigid Beams to account for the fact that those zones have an increased resistance. Two main
types of analyses are conducted in this study: 1) Nonlinear Static Pushover analysis (NSP) and 2) Incremental
Dynamic Analysis. These methods are briefly described.
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Figure 1: Plan and Elevation Sketch of Archetype Frame, modified from [18]
Nonlinear Static Pushover Analysis involves applying a predetermined pattern of lateral loads over the
height of the structure. The loads are applied in a progressively increasing manner as the structure gains (or
losses) strength. The results are the so called “pushover curves” wherein the deformation of a node control is
plotted against the lateral base shear. The NSP analysis is performed as per Section 6.3 of FEMA P695 (FEMA,
2009). The NSP analysis has the following characteristics: (1) The gravity loads were applied through a plain
load pattern and held constant in the model as they act permanently on the structure; (2) NSP analysis was
performed using a displacement controlled analysis to a maximum drift of 15% in increments of 0.0001 times
the height of the building and (3) a triangular shaped force distribution with an intensity of unity was applied as
lateral force.
The Nonlinear Response History (NRH) simulations are conducted to evaluate the effect of base strength
on the collapse potential of the building as well as the performance at defined level shaking. For the purpose of
this study, the performance objectives were selected in terms of drift levels. This is reasonable given that
buildings of this kind would be drift controlled rather than force controlled in terms of design. As exposed by
Ghobarah (2001) [19], it is acknowledged that the specific damage states associated to drift levels may vary
depending on the structure. The drift of a building is affected by several factors. They include the stiffness, the
strength and the ductility of the structure. The current practice in PBEE sets some general drift levels that can be
safely adopted and that provide meaningful estimates to improve the safety and economic aspects of the
structures. These drift thresholds are associated to performance objectives, which as defined by Ghobarah (2001)
[19], are statements of acceptable performance of the building. Table 4 exposes the drift levels selected in this
study.
The last two performance objectives, the associated with 5% and 10% drift, where selected by the authors
to track the response on extreme events and to try to characterize collapse. Normally, in an analysis such as the
MSA, collapse would be defined by conditions like instability on the building response or reduction of the elastic
stiffness in 80%. However, when this conditions cannot be met, due to the characteristics of the analysis, a drift
level is selected as the capacity of the structure. In this case, the latter described conditions would not be met as
global deterioration of the model is disregarded. Thus, and following the suggestions of Lee and Foutch (2002),
a drift of 10% is chosen to indicate global and complete collapse of the 4 story building.
The ground motion records are part of the ATC-63 project (FEMA 2009) [10]. In total, 32 far-field
acceleration histories were used. They have the following general characteristics: (1) The magnitude of the
earthquake records is larger than 6.5; (2) The distance to source for the far-field set of the ATC-63 is of more
than 10 km; (3) the ground motions correspond to strike slip and thrust fault mechanisms; (4) The specified soil
conditions for the set are of stiff or rock soil, with a Vs > 180 m/s; (5) The recording site is specified as a free-
field or ground floor of a small building; and finally, (6) The Peak Ground Acceleration (PGA) is greater than
0.2g, the Peak Ground Velocity (PGV) greater than 15 cm/s and the Lowest Unstable Frequency (LUF) of the
record is lower than 0.25 Hz. Thus, the use of this wide array of records provides the possibility of studying the
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response of the structure to distinct events and hereby to make relatively more certain predictions about its
performance.
Table 4: Performance Levels
Performance Level Damage State Drift (%)
Immediate Occupancy No Damage 0.2
Operational Repairable 0.5
Life Safe Irreparable 1.5
Near Collapse Severe 2.5
Near Collapse Severe 5
Collapse Collapse 10
5. Discussion of Results
Figure 2, represents the variation in the level of drift at the design spectral acceleration with respect to change in
strength level. In all the figures (Figures 2 to 14), the fixed and pinned assumptions have been represented as
boundaries rather than as discrete points so as to facilitate the comparison of the results. It is evident from Figure
2 that the level of drift experienced by the structure at the design Sa varies increasingly with decreasing
connection strength as expected. The maximum value that is specified in design for drifts at the design Sa is
around 2.0% to 2.5%. The figure shows that all connection levels compliment this requirement. The maximum
variation between the connections with the hysteretic spring is of around 0.23 % (from 1.65% in S1 to 1.88% in
S0.3). The middle strengths (S0.8 and S0.5), show little variation between them. The difference between the
assumptions and these four classes is notable. The fix assumption results in drifts as much as 0.93%, a value that
underestimates the real response of the structure. This can eventually have important implications in terms of
serviceability and even in safety, as the assumed response does not produce the real level of displacements for
the design level accelerations. On the other hand, the pinned assumption overestimates the displacements, thus
giving estimates on the safe side. It is important note is that characterizing the bases as yielding elements is
advantageous in terms of the drift predictions for the design Sa, as it better captures the real response and still
gives results that ensure the adequate performance of the building.
Then, Figures 3 to 8 are concerned with the median variation of the Sa at the different performance levels
with respect to the change in base class. At all drift levels, the fixed assumption, especially at low/serviceability
levels of drift, overestimates the median Sa needed to cause that level of drift. In contrast, the pinned bases are
always conservative. It has to be highlighted that at the 10% drift level, any of the ground motions reached this
“collapse” state for the fixed assumption, therefore giving more credit to the fact that modelling connections in
this fashion can lead to erroneous estimates of the performance of the building.
For low levels of drift, i.e. for 0.2 and 0.5%, the connections with the hysteretic model exhibit no variation
in the median Sa. Also, it can be seen that they are more closely represented by the pinned assumption. Their
similarity lies in the fact that this levels represent the Immediate Occupancy and Operational states of the
structure. Thus, the proposed approach would entail that the bases would not yield at this levels and thus their
response is the same. For the intermediate levels of drift 1.5%, 2.5% and 5%, which correspond to life safe and
near collapse states respectively, the structural response has a common trend with respect to the variation in
strength class. Clearly, as the drift level increases the difference between these connection levels increases.
Initially, at level 1.5%, only the S0.3 connection shows a decrease in median Sa. Then, the number of classes
decreasing their median with respect to S1 progressively increases with increasing the drift level examined.
Eventually, at 5% drift all the different strength levels show a clear decreasing trend in median spectral
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acceleration. Here, the effects of the variation in strength, i.e. in yield moment as defined in the hysteretic model,
are clearly captured.
As the intensity of the ground motions increase, and so the drift does, the different connection classes start
to yield in ascending order of strength, thus producing the progressively descending pattern observed in the
results. An important point to drawn from these figures is that this trend only starts to be notable for all strengths
after the life safe level (1.5%), where all the connections but S0.3 respond in the same manner. This suggest that
for this performance objectives, the level of strength of the connection only would become critical at very low
values with respect to the designed as per current codes (S1). As pointed out this differences increase and
become more notable and thus crucial at larger drift states (near collapse).
Previous decreasing trend only changes at the 10% drift level. At this level, the connections with lower
strengths perform better than the designed as per code. This could be explained by the fact that this lowering in
strength can enhance the ductility of the connections and thus, in limit states such as collapse they can produce a
better performance with respect to more robust bases. This fashion also suggests that if the level of drift was
increased further, by defining collapse at larger values, the performance of the connections will again stabilize. It
can be indicated that for connections designed as yielding elements and with 20% lower strength that of the
attached columns perform almost identically to the ones designed as S1 in terms of drift. Also, the S1 and S0.8
connections showed reasonable Sa measures for all the drift levels, ranging from 0.05g to about 2.9g for the
lightest and extreme cases relatively.
Figures 9 to 14 represent the change in median rotation with respect to the different strength connection
levels for a certain drift performance measure. The fixed assumption connection produced zero rotations at all
levels of drift as its definition in terms of modelling implies. When appropriate, a 50 mmrads tag is plotted, to
indicate a maximum allowed rotation defined in reference to codes of practice. Again, the pinned assumption
shows conservative results for all levels of drift. Also, a similar trend, associated with the yielding of the
connections, can be observed with the increasing levels of drift. For 0.2% and 0.5% all the rotations remain
between 5 and 6 mmrads for all connection strengths. At 1.5% drift, all connections kept this trend, having
constant values between 10 and 15 mmrads. However, there was a particular lowering in in the rotation for the
S0.3 level. For higher drift levels the rotations subsequently increase. At 5% drift, the second near collapse state,
the rotations for the lower connection levels surpass the threshold of 50 mmrads, indicating excessive demands
in the bases. At 10% drift, all the connection levels are well over the 50 mmrads with rotations around the 100
mmrads. However they keep the same increasing trend with decreasing strengths. Rotations thus characterized
another critical aspect to attend when assessing the performance of the structure. Although the response
generally maps that described by the Sa levels at the different drifts, at limit states rotations become more critical
as they become very large.
Figure 2: Drift at Design Spectral Acceleration Figure 3: Spectral Acc. at 0.2% Drift Level
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Figure 4: Spectral Acc. at 0.5% Drift Level Figure 5: Spectral Acc. at 1.5% Drift Level
Figure 6: Spectral Acc. at 2.5% Drift Level Figure 7: Spectral Acc. at 5% Drift Level
Figure 8: Spectral Acc. at 10% Drift Level Figure 9: Rotation at 0.2% Drift Level
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Figure 10: Rotation at 0.5% Drift Level Figure 11: Rotation at 1.5% Drift Level
Figure 12: Rotation at 2.5% Drift Level Figure 13: Rotation at 5% Drift Level
Figure 14: Rotation at 10% Drift Level
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6. Acknowledgements
The authors would like to recognize Dr. Christian Malaga-Chuquitaype, from Imperial College
London, who gave support and advice to the authors during the early stages of this investigation. The
authors would also like to thank The National Secretariat of Higher Education, Science, Technology,
and Innovation of Ecuador (SENESCYT) whose graduate fellowship provided support for the second.
author.
7. References
[1] Lignos and Krawinkler (2007). “A Database in Support of Modeling of Component Deterioration for
Collapse Prediction of Steel Frame Structures”. Structural Engineering Frontiers.
[2] DeWolf J.T., and Sarisley, E.F. (1980), “Column Base Plates with Axial Loads and Moments,” Journal of
the Structural Division, ASCE, Vol. 106, No. 11, November 1980, pp. 2167-2184.
[3] Astaneh, A., Bergsma, G., and Shen J.H. (1992). “Behavior and Design of Base Plates for Gravity, Wind and
Seismic Loads,” Proceedings of the National Steel Construction Conference, Las Vegas, Nevada, AISC,
Chicago, Illinois.
[4] Burda, J.J., and Itani, A.M. (1999). “Studies of Seismic Behavior of Steel Base Plates,” Report No. CCEER
99-7, Reno (NV): Center of Civil Engineers Earthquake Research, Department of Civil and Environmental
Engineering, University of Nevada, NV.
[5] Fahmy, M., Stojadinovic., and Goel, S.C. (1999). “Analytical and Experimental Studies on the Seismic
Response of Steel Column Bases,” Proceedings of the 8th Canadian Conference on Earthquake Engineering.
[6] Gomez, I.R., Kanvinde, A.M., and Deierlein, G.G. (2010). “Exposed column base connections subjected to
axial compression and flexure,” Report Submitted to the American Institute of Steel Construction, Chicago, IL.
[7] Kanvinde, A.M., Higgins, P., Cooke, R.J., Perez, J., and Higgins, J., (2014). “Column base connections for
hollow steel sections: seismic performance and strength models,” Journal of Structural Engineering, ASCE.
10.1061/ (ASCE) ST.1943-541X.0001136.
[8] Zareian, F. and Kanvinde, A. (2013). “Effect of Column Base Flexibility on the Seismic Response and
Safety of Steel Moment Resisting Frames”. Earthquake Spectra. Vol. 29, No. 4, pp. 1537-1559.
[9] Jalayer, F. and Cornell, C. a., 2009. Alternative non-linear demand estimation methods for probability based
seismic assessments. Earthquake Engineering and Structural Dynamics, 38(8), pp.951–972.
[10] FEMA, 2009. Quantification of Building Seismic Performance Factors. FEMA-P695, Federal Emergency
Management Agency, Washington, D.C.
[11] AISC 341-10. (2010). “Seismic provisions for structural steel buildings”. ANSI/AISC 341, Chicago.
[12] Aviram, A., Stojadinovic, B. and Kiureghian, A. Der, 2010. Performance and reliability of exposed column
base plate connections for steel moment-resisting frames. , (August), p.190.
[13] Kanvinde, A.M., and Grilli, D.A., (2013). “Special Moment Frame Base Connection: Design Example 8,”
2012 IBC SEAOC Structural/Seismic Design Manual, Volume 4, Examples for Steel-Frame Buildings, 255-280.
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[14] Fisher, J.M., and Kloiber, L.A. (2006). “Steel Design Guide 1 – Base Plate and Anchor Rod Design,” 2nd
Ed., AISC 801-06, American Institute of Steel Construction, Inc., Chicago, IL.
[15] Gomez, I.R., Kanvinde, A.M., and Deierlein, G.G. (2010). “Exposed column base connections subjected to
axial compression and flexure,” Report Submitted to the American Institute of Steel Construction, Chicago, IL.
[16] Kanvinde, A.M., Grilli, D.A., and Zareian, F. (2012). “Rotational Stiffness of Exposed Column Base
Connections: Experiments and Analytical Models”. Journal of Structural Engineering. Vol.138, No 5.
[17] Ibarra, L.F., Medina, R.A., Krawinkler, H. (2005). “Hysteretic models that incorporate strength and
stiffness deterioration,” Earthquake Engineering and Structural Dynamics, Wiley, 34: 1489-1511.
[18] Mazzoni, S., McKenna, F., Scott, M.H., Fenves, G.L., (2009). Open System for Earthquake Engineering
Simulation User Command Language Manual, OpenSees Version 2.0. Pacific Earthquake Engineering Research
Center, University of California: Berkeley, CA, 2009.
[19] Shaw, S.M., 2010. Seismic Performance of Partial Joint Penetration Welds in Steel Moment Resisting
Frames.
[20] Ghobarah, A., 2001. Performance-based design in earthquake engineering: state of development.
Engineering Structures, 23(8), pp.878–884.
[21] Lee, K. & Foutch, D. a., 2002. Performance evaluation of new steel frame buildings for seismic loads.
Earthquake Engineering & Structural Dynamics, 31(3), pp.653–670.
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