SEISMIC RETROFIT OF RECTANGULAR BRIDGE COLUMNS USING CFRP WRAPPING
Author: MESAY ABEBAW ENDESHAW | Size: 2.2 MB | Format:PDF | Quality:Unspecified | Publisher: WASHINGTON STATE UNIVERSITY Department of Civil and Environmental Engineering MAY 2008 | Year: 2008 | pages: 88
This study investigated retrofitting measures for improving the seismic performance of rectangular columns in existing bridges. Experimental tests were conducted on 0.4-scale column specimens which incorporated details that were selected
to represent deficiencies present in older bridges in Washington State. Two unretrofitted specimens were tested to examine the performance of the as-built columns incorporating lap splices at the base of the columns and deficient transverse reinforcement. Five columns were retrofitted with carbon fiber reinforced polymer (CFRP) composite wrapping and one specimen was retrofitted with a steel jacket. The specimens were subjected to increasing levels of cycled lateral displacements under constant axial load.
Specimen performance was evaluated based on failure mode, displacement ductility
capacity and hysteretic behavior.
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Seismic retrofit of masonry buildings with polymer grid
Author: A. Dusi & E. Manzoni Numeria Consulting Srl, Cremona, Italy. M. Mezzi Department of Civil and Environmental Engineering, University of Perugia, Perugia, Italy. G. Stevens Maccaferri NZ Ltd, Penrose, Auckland, New Zealand. | Size: 622 KB | Format:PDF | Quality:Unspecified | Publisher: roceedings of the Ninth Pacific Conference on Earthquake Engineering Building an Earthquake-Resilient Society 14-16 April, 2011, Auckland, New Zealand | Year: 2011 | pages: 8
The performance of masonry walls reinforced using innovative polymer grids embedded into thin plaster layers as a tools for the seismic enhancement of brick masonry buildings have been investigated by experimental tests. A number of diagonal compression, shear compression and out-of-plane tests were executed on sample panels; experimental activities included pseudo-dynamic and shaking table tests on infills and reduced scaled building mock-ups, respectively. The results of the experimental activities are presented and discussed. Experimental campaigns have been supported by theoretical and numerical investigations; based on the experimental data and on the results of detailed numerical simulations, simplified models to be used as tools for the design of the retrofitting intervention are hereinafter proposed. The models, calibrated on the experimental evidence, properly consider the collapse mechanisms as well as the grid
effect in the evolution of the above mentioned mechanisms.
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Performance-Based Seismic Retrofit Strategy for Existing Reinforced Concrete Frame Systems Using Fiber-Reinforced Polymer Composites
Author: Stefano Pampanin ; Davide Bolognini ; and Alberto Pavese | Size: 2.2 MB | Format:PDF | Quality:Unspecified | Publisher: Univ. of Canterbury, Christchurch, New Zealand. | Year: 2007 | pages: 16
The feasibility and efficiency of a seismic retrofit intervention using externally bonded fiber-reinforced polymer composites on
existing reinforced concrete frame systems, designed prior to the introduction of modern standard seismic design code provisions in the mid-1970s, are herein presented, based on analytical and experimental investigations on beam-column joint subassemblies and frame systems. A multilevel retrofit strategy, following hierarchy of strength considerations, is adopted to achieve the desired performance. The expected sequence of events is visualized through capacity-demand curves within M-N performance domains. An analytical procedure
able to predict the enhanced nonlinear behavior of the panel zone region, due to the application of CFRP laminates, in terms of shear strength .principal stresses. versus shear deformation, has been developed and is herein proposed as a fundamental step for the definition of a proper retrofit solution. The experimental results from quasistatic tests on beam-column subassemblies, either interior and exterior, and on three-storey three-bay frame systems in their as-built and CFRP retrofitted configurations, provided very satisfactory confirmation
of the viability and reliability of the adopted retrofit solution as well as of the proposed analytical procedure to predict the actual sequence
of events.
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Reinforced concrete columns with non-seismic detailing are often vulnerable to the effects of a major earthquake.
In this study, the structural behaviour of undamaged and moderately damaged columns, which were retrofitted
with carbon fiber reinforced polymers (CFRP) is investigated. The experimental program consists of four
specimens having inadequate tie spacing, 90 degree hooks and plain reinforcing bars that were tested under
lateral cyclic displacement excursions under a constant axial load of approximately 27% of the axial load
carrying capacity. One reference specimen without any strengthening and one strengthened specimen with
strengthening but without any pre-damage were tested. In addition, two similar specimens tested to moderate
damage level of 2% drift ratio were repaired and retested. In one of the pre-damaged columns the repairing
process was performed in the presence of constant axial load. The main parameters investigated in this study
were the presence of axial load on the column during repairing, effect of pre-damage on ultimate displacements
and the effect of CFRP wrapping on strengthened and repaired columns. The ultimate drift ratio for retrofitted
columns increased to 6% which was only 3.5% for the reference column. Severe stiffness degradation was
observed in both of the repaired columns due to the moderate level of pre-damage. For the repaired columns, the
presence of the axial load during repairing did not significantly affect the ultimate drift ratio significantly
however the enhancement in strength was not observed as compared to its companion specimen.
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SEISMIC RETROFIT OF REINFORCED CONCRETE BRIDGES WITH FIBER REINFORCED POLYMER COMPOSITES: STATE-OF-THE-ART REVIEW
Author: Zahra Riahi and Farzad Faridafshin | Size: 183 KB | Format:PDF | Quality:Unspecified | Publisher: The 14 th World Conference on Earthquake Engineering October 12-17, 2008, Beijing, China | Year: 2008 | pages: 12
This state-of-the-art manuscript addresses seismic retrofit of deficient reinforced concrete (RC) bridges whose
vulnerability has been demonstrated repeatedly in previous seismic events. A class of high performance
materials, Fiber Reinforced Polymer composites (FRP), with versatile applications in repair and rehabilitation
has been used for this purpose.
Mechanical and durability properties of externally bonded FRP's, their merits over conventional materials and
retrofit techniques, general seismic flaws and failure modes, and the effects of FRP wraps on the seismic
performance of lateral load resisting components of RC bridges are investigated, and practical solutions which
help improve the efficacy of FRP's are proposed.
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Dynamic Failure of Composite and Sandwich Structures
Author: Serge Abrate, Bruno Castanié and Yapa D. S. Rajapakse | Size: 24 MB | Format:PDF | Quality:Unspecified | Publisher: Springer | Year: 2013 | pages: 710 | ISBN: 9789400753280, 9789400753297, 9400753284
This book presents a broad view of the current state of the art regarding the dynamic response of composite and sandwich structures subjected to impacts and explosions. Each chapter combines a thorough assessment of the literature with original contributions made by the authors.
The first section deals with fluid-structure interactions in marine structures. The first chapter focuses on hull slamming and particularly cases in which the deformation of the structure affects the motion of the fluid during the water entry of flexible hulls. Chapter 2 presents an extensive series of tests underwater and in the air to determine the effects of explosions on composite and sandwich structures. Full-scale structures were subjected to significant explosive charges, and such results are extremely rare in the open literature. Chapter 3 describes a simple geometrical theory of diffraction for describing the interaction of an underwater blast wave with submerged structures.
The second section addresses the problem of impact on laminated composite structures with chapters devoted to ballistic impacts on pre-stressed composite structures, tests developed to simulate dynamic failure in marine structures, damage mechanisms and energy absorption in low velocity impacts, perforation, the numerical simulation of intra and inter-ply damage during impact, and hail impact on laminated composites.
Sandwich structures with laminated facings are considered in Section 3 with chapters dealing with the discrete modeling of honeycomb core during the indentation of sandwich structures, the behavior of fold core sandwich structures during impact, and impact on helicopter blades. The fourth section consists of two chapters presenting experimental results and numerical simulation of composite structures subjected to crash.
This volume is intended for advanced undergraduate and graduate students, researchers, and engineers interested and involved in analysis and design of composite structures.
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The special focus of this proceeding is to cover the areas of infrastructure engineering and sustainability management. The state-of-the art information in infrastructure and sustainable issues in engineering covers earthquake, bioremediation, synergistic management, timber engineering, flood management and intelligent transport systems. It provides precise information with regards to innovative research development in construction materials and structures in addition to a compilation of interdisciplinary finding combining nano-materials and engineering.
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FIB 54: Structural Concrete Textbook on behaviour, design and performance, Second edition Volume 4: Design of concrete buildings for fire resistance, design of members, practical aspects
Size: 52 MB | Format:PDF | Quality:Unspecified | Publisher: FIB - The International Federation for Structural Concrete (fédération internationale du béton) | Year: 2010 | Pages: 203 | ISBN: 9782883940949
The second edition of the Structural Concrete Textbook is an extensive revision that reflects advances in knowledge and technology over the past decade. It was prepared in the intermediate period from the CEP-FIP Model Code 1990 (MC90) to fib Model Code 2010 (MC2010), and as such incorporates a significant amount of information that has been already finalized for MC2010, while keeping some material from MC90 that was not yet modified considerably.
The objective of the Textbook is to give detailed information on a wide range of concrete engineering from selection of appropriate structural system and also materials, through design and execution and finally behavior in use.
The revised fib Structural Concrete Textbook covers the following main topics:
phases of design process, conceptual design, short and long term properties of conventional concrete (including creep, shrinkage, fatigue and temperature influences), special types of concretes (such as self compacting concrete, architectural concrete, fibre reinforced concrete, high and ultra high performance concrete), properties of reinforcing and prestressing materials, bond, tension stiffening, moment-curvature, confining effect, dowel action, aggregate interlock;
structural analysis (with or without time dependent effects), definition of limit states, control of cracking and deformations, design for moment, shear or torsion, buckling, fatigue, anchorages, splices, detailing;
design for durability (including service life design aspects, deterioration mechanisms, modelling of deterioration mechanisms, environmental influences, influences of design and execution on durability);
fire design (including changes in material and structural properties, spalling, degree of deterioration), member design (linear members and slabs with reinforcement layout, deep beams); management, assessment, maintenance, repair (including, conservation strategies, risk management, types of interventions) as well as aspects of execution (quality assurance), formwork and curing.
The updated Textbook provides the basics of material and structural behavior and the fundamental knowledge needed for the design, assessment or retrofitting of concrete structures. It will be essential reading material for graduate students in the field of structural concrete, and also assist designers and consultants in understanding the background to the rules they apply in their practice. Furthermore, it should prove particularly valuable to users of the new editions of Eurocode 2 for concrete buildings, bridges and container structures, which are based only partly on MC90 and partly on more recent knowledge which was not included in the 1999 edition of the Textbook.
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FIB 53: Structural Concrete Textbook on behaviour, design and performance, Second edition Volume 3: Design of durable concrete structures
Size: 65 MB | Format:PDF | Quality:Unspecified | Publisher: FIB - The International Federation for Structural Concrete (fédération internationale du béton) | Year: 2009 | Pages: 392 | ISBN: 9782883940932
The second edition of the Structural Concrete Textbook is an extensive revision that reflects advances in knowledge and technology over the past decade. It was prepared in the intermediate period from the CEP-FIP Model Code 1990 (MC90) to fib Model Code 2010 (MC2010), and as such incorporates a significant amount of information that has been already finalized for MC2010, while keeping some material from MC90 that was not yet modified considerably.
The objective of the Textbook is to give detailed information on a wide range of concrete engineering from selection of appropriate structural system and also materials, through design and execution and finally behavior in use.
The revised fib Structural Concrete Textbook covers the following main topics:
phases of design process, conceptual design, short and long term properties of conventional concrete (including creep, shrinkage, fatigue and temperature influences), special types of concretes (such as self compacting concrete, architectural concrete, fibre reinforced concrete, high and ultra high performance concrete), properties of reinforcing and prestressing materials, bond, tension stiffening, moment-curvature, confining effect, dowel action, aggregate interlock;
structural analysis (with or without time dependent effects), definition of limit states, control of cracking and deformations, design for moment, shear or torsion, buckling, fatigue, anchorages, splices, detailing;
design for durability (including service life design aspects, deterioration mechanisms, modelling of deterioration mechanisms, environmental influences, influences of design and execution on durability);
fire design (including changes in material and structural properties, spalling, degree of deterioration), member design (linear members and slabs with reinforcement layout, deep beams); management, assessment, maintenance, repair (including, conservation strategies, risk management, types of interventions) as well as aspects of execution (quality assurance), formwork and curing.
The updated Textbook provides the basics of material and structural behavior and the fundamental knowledge needed for the design, assessment or retrofitting of concrete structures. It will be essential reading material for graduate students in the field of structural concrete, and also assist designers and consultants in understanding the background to the rules they apply in their practice. Furthermore, it should prove particularly valuable to users of the new editions of Eurocode 2 for concrete buildings, bridges and container structures, which are based only partly on MC90 and partly on more recent knowledge which was not included in the 1999 edition of the Textbook.
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FIB 50: Concrete structures for oil and gas fields in hostile marine environments
Size: 23 MB | Format:PDF | Quality:Unspecified | Publisher: FIB - The International Federation for Structural Concrete (fédération internationale du béton) | Year: 2009 | Pages: 37 | ISBN: 9782883940901
Concrete offshore structures have been successfully delivered to the international oil and gas industry for more than 35 years. Some 50 major concrete platforms of different shapes and sizes, supporting large production and storage facilities, are currently operating in hostile marine environments worldwide and have excellent service records.
After some years with little development activity, today there is a renewed interest in robust structures for the Arctic environment, for Liquefied Natural Gas (LNG) terminals and for special floating barges and vessels. Currently, concrete solutions are being considered for projects north and east of Russia, north of Norway and offshore Newfoundland, among others.
Concrete is also in increasing demand in built up coastal areas for a variety of purposes such as harbour works, tunnels and bridges, cargo terminals, parking garages and sea front housing developments where durability and robustness are essential.
The mandate of fib Task Group 1.5 was to gather the experience and know-how pertinent to the development, design and execution of offshore concrete structures, and to elaborate on the applicability of concrete structures for the Arctic environments. The findings of the Task Group are presented in fib Bulletin 50.
The report is based on experience gained from the design, execution and performance of a number of offshore concrete structures around the world and in particular in the North Sea. Ongoing inspections have shown excellent durability and structural performance, even in structures that have exceeded their design lives, in conditions often characterized by extreme wave loads, freezing conditions, hurricane force winds and seismic actions. This forms the "background" for discussing the applicability of concrete structures for the Arctic regions.
Although to a large extent dedicated to oil- and gas- related structures, the report is also relevant to other marine applications where the same design principles, material selection criteria and construction methods apply.
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