Seismic Retrofitting of Rectangular Bridge Columns with Composite Straps

1997 ◽  
Vol 13 (2) ◽  
pp. 281-304 ◽  
Author(s):  
H. Saadatmanesh ◽  
M. R. Ehsani ◽  
L. Jin
Keyword(s):  
Plastic Hinge ◽  
Poor Performance ◽  
High Strength ◽  
Bridge Columns ◽  
Absorption Capacity ◽  
Seismic Retrofitting ◽  
Frp Composites ◽  
Reinforced Polymer ◽  
Seismic Forces ◽  
Reversed Cyclic

Behavior of typical rectangular bridge columns with substandard design details for seismic forces was investigated. The poor performance of this type of column attested to the need for effective and economical seismic upgrading techniques. A method utilizing fiber reinforced polymer (FRP) composites to retrofit existing bridge columns is investigated in this paper. High-strength FRP straps are wrapped around the column in the potential plastic hinge region to increase confinement and to improve the behavior under seismic forces. Five rectangular columns with different reinforcement details were constructed and tested under reversed cyclic loading. Two columns were not retrofitted and were used as control specimens so that their hysteresis response could be compared with those for retrofitted columns. The results of this study indicated that significant improvement in ductility and energy absorption capacity can be achieved as a result of this retrofitting technique.

Seismic Retrofit and Repair of Circular Bridge Columns with Advanced Composite Materials

1999 ◽  
Vol 15 (4) ◽  
pp. 747-764 ◽  
Author(s):  
R. Ma ◽  
Yan Xiao
Keyword(s):  
Brittle Failure ◽  
Plastic Hinge ◽  
Plastic Region ◽  
Experimental Studies ◽  
Seismic Retrofit ◽  
Bridge Columns ◽  
Absorption Capacity ◽  
Scale Model ◽  
Dramatic Improvement ◽  
Lap Splice

Experimental studies on seismic retrofit and repair of typical circular bridge columns with poor lap splice details utilizing prefabricated glass fiber reinforced polymer (FRP) composite jackets and epoxy are presented in this paper. A total of seven tests on three 1/2-scale model columns were conducted. One column was tested under “as-built” condition and the other two columns were retrofitted with prefabricated composite individual and continuous jackets respectively. The jackets were applied in the potential plastic hinge region of the column to increase its lateral confinement. Brittle failure was observed in the “as-built” model column due to the bond deterioration of lap spliced longitudinal reinforcement. This brittle failure was prevented in the retrofitted columns. The repairing of failed “as-built” column by injecting epoxy into damaged plastic region resulted in significant stiffening of the portion and increase of capacity and ductility. The second repair of the specimen using both epoxy injection and prefabricated composite jacketing effectively improved its behavior further. The results of this study indicated that dramatic improvement in ductility and energy absorption capacity of columns can be achieved using these retrofit and repair methods.

Analysis of Equivalent Plastic Hinge Length of High Strength Concrete Bridge Columns by Using High Strength Reinforcements

2011 ◽  
Vol 90-93 ◽  
pp. 1144-1148 ◽  
Author(s):  
Yong Duo Liang ◽  
Zhi Guo Sun ◽  
Gong Cai Chi ◽  
Bing Jun Si
Keyword(s):  
High Strength Concrete ◽  
Plastic Hinge ◽  
Influence Factors ◽  
Load Ratio ◽  
High Strength ◽  
Bridge Columns ◽  
Concrete Bridge ◽  
Test Results ◽  
Strength Concrete ◽  
Plastic Hinge Length

The use of high strength reinforcement and high strength concrete in bridge columns is increasing due to many advantages of the high strength materials. In order to study the equivalent plastic hinge length of reinforced concrete bridge columns，37 column test results by using high strength reinforcement and high concrete were collected. Then, the equations proposed by Priestley, Paulay, Telemachos and JTG/T B02-01-2008 to predict the equivalent plastic hinge length of the columns were evaluated based on the experimental results. Influence factors which affect the equivalent plastic hinge length of high strength concrete bridge columns were studied through grey correlation analysis. It is found that, comparing to test results, all the proposed equations show considerable scatter in estimating the plastic hinge length of the high strength bridge columns using high strength reinforcement. The equations proposed by Paulay, Telemachos are not safe, while Priestley and JTG/T B02-01-2008 proposed equations give conservative results. Among the influence factors, the diameter of longitudinal reinforcement is the most important, secondly is the column length and section width. The axial load ratio of the column and transverse reinforcement of the specimens show small influence.

Experimental Analysis of the Bond Behavior of Glass, Carbon, and Steel FRCM Composites

2014 ◽  
Vol 624 ◽  
pp. 371-378 ◽  
Author(s):  
Tommaso D'Antino ◽  
Carlo Pellegrino ◽  
Christian Carloni ◽  
Lesley H. Sneed ◽  
Giorgio Giacomin
Keyword(s):  
Stress Transfer ◽  
High Strength ◽  
Fiber Reinforced ◽  
Bond Behavior ◽  
Cementitious Matrix ◽  
Frp Composites ◽  
Reinforced Polymer ◽  
The Matrix ◽  
Glass Carbon ◽  
Concrete Matrix

In recent decades, the construction industry has witnessed a rapid growth of interest in strengthening and retrofitting of existing reinforced concrete (RC) and masonry structures. Fiber reinforced polymer (FRP) composites have gained great popularity, and several studies are now available in the literature on their use in strengthening and retrofit applications. Promising newly-developed composite materials are represented by the so-called fiber reinforced cementitious matrix (FRCM) composites. FRCM composites are comprised of high strength fibers embedded within a cementitious matrix that is responsible for the stress transfer between the existing structure and the strengthening material. FRCM composites are still in their infancy, and very limited results are available in the literature on RC and masonry strengthening applications. This study presents an experimental campaign conducted on different FRCM composites comprised of glass, carbon, or steel fibers embedded within two different cementitious matrices and applied to concrete prisms. The single-lap direct-shear test was used to study the stress-transfer mechanism between the FRCM composite and the concrete substrate. Two different composite bonded lengths were investigated. Debonding occurred at the matrix-fiber interface for some of the composites tested and at the concrete-matrix interface for others. This work contributes to the study of the bond behavior of FRCM composites, which represents a key issue for the effectiveness of FRCM composite strengthening.

scholarly journals An innovative tubular standing support incorporating PVC and FRP composites: laboratory tests

2021 ◽  
Author(s):  
Baisheng Zhang ◽  
Hongchao Zhao
Keyword(s):  
Weight Ratio ◽  
High Strength ◽  
Test Results ◽  
Compression Tests ◽  
Frp Composites ◽  
Frp Composite ◽  
Reinforced Polymer ◽  
Deformation Ability ◽  
Fibre Reinforced Polymer ◽  
Infill Material

Abstract With the depletion of shallow resources, the drawbacks of conventional bolting system in sustaining the integrity of the roadway have drawn much attention. Developing the innovative secondary standing support is therefore to be urgent. This paper presents a hybrid tubular standing support, which consists of an exterior container made of PVC and fibre-reinforced polymer (FRP) composites and the infill material made of coal rejects and high flowable cementitious grout material. Compared with other marketable standing support, the combination application of the large rupture strain PVC tube and the FRP composite with high strength-to-weight ratio can provide the effective confinement to infill material, which may result in the strain hardening behaviour. The use of coal reject to generate the backfill material is believed to be effective and thus is attractive from the design aspect. To verify these mentioned advantages, a series of compression tests were conducted on this FRP-PVC tubular standing support (FPTSS) with different thickness of the FRP jacket. In addition, the compression tests were also conducted to investigate the compressive behaviour of FRP tubular standing support (FTSS) and PVC tubular standing support (PTSS). Test results indicated that the combination of FRP and PVC composite achieve the superior behaviour either in terms of the compressive strength or the deformation ability.

Confinement of Masonry Columns with Steel and Basalt FRCM Composites

2017 ◽  
Vol 747 ◽  
pp. 342-349 ◽  
Author(s):  
Mattia Santandrea ◽  
Giovanni Quartarone ◽  
Christian Carloni ◽  
Xiang Lin Gu
Keyword(s):  
Compressive Load ◽  
Basalt Fiber ◽  
High Strength ◽  
Fiber Reinforced Polymer ◽  
Vapor Permeability ◽  
Fiber Reinforced ◽  
Promising Alternative ◽  
Frp Composites ◽  
Reinforced Polymer ◽  
Externally Bonded

The rehabilitation of existing masonry elements by means of jacketing of columns using composite materials is becoming a remarkable technique in several applications that aim to increase the strength of existing masonry buildings. Fiber reinforced cementitious matrix (FRCM) composites are a newly developed strengthening system that consist of high-strength fibers embedded in a cementitious grout and externally bonded to the substrate. High resistance to fire and high temperatures, ease of handling during application, and vapor permeability with the substrate are some of the characteristics that make FRCMs a promising alternative to traditional organic composites such as fiber reinforced polymer (FRP) composites. This work presents the results of an experimental study carried out to understand the behavior of masonry columns with a square cross-section confined by steel and basalt fiber sheets embedded in a mortar matrix subjected to monotonic concentric compressive load. The effectiveness of the confinement is studied in terms of load-bearing capacity with respect to unconfined columns. The effect of corner radius for columns confined with basalt fibers is investigated.

scholarly journals Shear Strength of Unreinforced Masonry Wall Retrofitted with Fiber Reinforced Polymer and Hybrid Sheet

2015 ◽  
Vol 2015 ◽  
pp. 1-13
Author(s):  
Yun-Cheul Choi ◽  
Hyun-Ki Choi ◽  
Dongkeun Lee ◽  
Chang Sik Choi
Keyword(s):  
Shear Strength ◽  
Effective Strain ◽  
Unreinforced Masonry ◽  
Seismic Retrofitting ◽  
Fiber Reinforced Polymer ◽  
Fiber Reinforced ◽  
Cross Sectional ◽  
Historical Structures ◽  
Frp Composites ◽  
Reinforced Polymer

Unreinforced masonry (URM) structures represent a significant portion of existing historical structures around the world. Recent earthquakes have shown the need for seismic retrofitting for URM structures. Various types of strengthening methods have been used for URM structures. In particular, a strengthening technique using externally bonded (EB) fiber reinforced polymer (FRP) composites has attracted engineers since EB FRP materials effectively enhance the shear strength of URM walls with negligible change to cross-sectional area and weight of the walls. Research has been extensively conducted to determine characteristics of URM walls strengthened with EB FRP materials. However, it is still difficult to determine an appropriate retrofitting level due to the complexity of mechanical behavior of strengthened URM walls. In this study, in-plane behavior under lateral loading was, therefore, investigated on a full-scale nonstrengthened URM wall and URM walls retrofitted with two different FRP materials: carbon (CFRP) and hybrid (HFRP) sheets. The test results indicated that both FRP composites were effective in increasing shear strength in comparison with the control specimen. However, better performance was obtained with HFRP compared to CFRP. In addition, an equation for estimating effective strain was proposed, and the theoretical results were in good agreement with the experimental ones.

Experimental Study on Confinement Effectiveness of Different CFRP Hybridized Methods in Retrofitting Shear Deficient HSC Columns

2012 ◽  
Vol 166-169 ◽  
pp. 1565-1573
Author(s):  
Su Yan Wang ◽  
Huai Chao Cao ◽  
Wei Lu ◽  
Yi Liu
Keyword(s):  
High Strength Concrete ◽  
High Strength ◽  
Concrete Columns ◽  
Shear Capacity ◽  
Fiber Reinforced Polymer ◽  
Carbon Fiber Reinforced Polymer ◽  
Reinforced Polymer ◽  
Reversed Cyclic ◽  
Hybridized Methods ◽  
High Strength Concrete Columns

The effectiveness of four different carbon fiber reinforced polymer (CFRP) hybridized methods to retrofit the high strength concrete columns with shear capacity deficiency for improving the shear behavior is described in this paper. These retrofitting methods include the wrapped jacketing, the L-shaped jacketing combined with wrapped jacketing, the clamp plates plus wrapped jacketing and the L-shaped jacketing, clamp plates and wrapped jacketing. Five specimens were tested under low reversed cyclic loading. The influence of retrofitting on the failure mode, ductility, strength, stiffness degradation, and distribution of CFRP strain is analyzed. The results indicate that the retrofitted specimens exhibit high levels of ductility superior to the reference specimen. Among the four retrofitting methods, the effectiveness of method of only the wrapped jacketing is the worst, the method of the clamp plates plus wrapped jacketing has better performance compared to the method of the L-shaped jacketing combined with wrapped jacketing, and the method of the L-shaped jacketing, clamp plates and wrapped jacketing performs best.

Investigation of CFRP- and GFRP-confined concrete cylinders under monotonic and cyclic loading

2014 ◽  
Vol 21 (4) ◽  
pp. 607-614 ◽  
Author(s):  
Ali A. Mortazavi ◽  
Mostafa Jalal
Keyword(s):  
Cyclic Loading ◽  
Axial Strain ◽  
Glass Fibers ◽  
Weight Ratio ◽  
High Strength ◽  
Confined Concrete ◽  
Strain Behavior ◽  
Frp Composites ◽  
Reinforced Polymer ◽  
Concrete Cylinders

AbstractFiber reinforced polymer (FRP) composites have found increasingly wide applications in engineering due to their high strength-to-weight ratio and high corrosion resistance. One important application of FRP composites is as a confining material for concrete, which can enhance both the compressive strength and the ultimate axial strain of concrete. With this respect, the stress-strain behavior of FRP-confined concrete, under both monotonic and cyclic compression, needs to be properly understood and modeled. This paper presents details of an experimental work carried out on concrete cylinders wrapped with FRP materials and subjected to both monotonic and cyclic loading. A total number of 12 FRP confined concrete specimens and 10 control specimens with a diameter of 100 mm and a height of 200 mm were cast and cured under the same conditions, and two FRP materials (carbon fibers (CFRP) and glass fibers (GFRP)) were used for the construction of the FRP jackets. The effect of the type of confinement material, reinforcement ratio based on the jacket stiffness, and type of loading is examined. A model that predicts the behavior of confined concrete, which takes into account the stiffness and effectiveness of different confinement materials is also briefly introduced.

scholarly journals Cold-Formed Steel Beam-Column Joints with Latex Layer Wrapping

2019 ◽  
Vol 9 (2) ◽  
pp. 3132-3135
Keyword(s):  
High Strength ◽  
Absorption Capacity ◽  
Steel Beam ◽  
Energy Absorption Capacity ◽  
Primary Element ◽  
Strength Capacity ◽  
Steel Column ◽  
Ductile Steel ◽  
Cold Formed Steel ◽  
Seismic Forces

Columns are the primary element of a structure and are the first element to face the effect of lateral load during an earthquake. To resist such lateral seismic loading high strength and ductile steel frames with higher energy absorption capacity are generally preferred. The nominal ductile capacity of the steel can be boosted up with additional wrapping that could optimize the seismic performance significantly. The present work deals on the behaviour of cold-formed steel beam and cold formed steel column wrapped with latex layers for strengthening. The specimens were subjected to reversed quasi-static cyclic loading to partially simulate the seismic forces. Experimental results shows significant increase in strength capacity of beam-column with latex layer wrapping.

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