Rapid Repair Technique to Improve Plastic Dissipation of Existing Chinese RC Bridges

2016 ◽  
Vol 847 ◽  
pp. 204-209 ◽  
Author(s):  
Davide Lavorato ◽  
Camillo Nuti ◽  
Bruno Briseghella ◽  
Silvia Santini ◽  
Jun Qing Xue
Keyword(s):  
Shear Strength ◽  
Strong Earthquake ◽  
Plastic Hinge ◽  
Cyclic Tests ◽  
Rapid Repair ◽  
Repair Technique ◽  
Plastic Dissipation ◽  
The One ◽  
Existing Bridges ◽  
Frp Wrapping

A rapid repair and retrofitting technique for reinforced concrete (rc) Chinese existing bridges damaged by a strong earthquake, is proposed and tested. These bridges were designed according to Chinese codes [1] [2] [3] but with insufficient transversal steel reinforcement. The damaged rebar and concrete parts were replaced by new bar systems and concrete cast respectively. Finally, a C-FRP wrapping was applied to increase the insufficient shear strength and to guarantee the necessary ductility in plastic hinge. This repair technique is an upgrade of the one tested with very good results during a previous experimental research [4] on bridge designed according to old Italian code [5] without proper seismic details. A new bar system assures that plastic dissipation is distributed in plastic hinge only. Some pier specimens (in scale 1:6) were built with and without the new bar systems. These specimens were tested by cyclic tests at Fuzhou University lab (China) to evaluate the effectiveness of the intervention.

Nonlinear Seismic Responses Analysis of Jinwan Square No.9 Building

2014 ◽  
Vol 919-921 ◽  
pp. 999-1002
Author(s):  
Lin Qi ◽  
Zhao Wei Huang ◽  
Xue Ying Hu
Keyword(s):  
Shear Strength ◽  
Strong Earthquake ◽  
Seismic Analysis ◽  
Plastic Hinge ◽  
Time History ◽  
Beam Element ◽  
Structure Design ◽  
Three Dimension ◽  
Fiber Wall ◽  
Set Up

Nonlinear time history seismic analysis of Jinwan square No. 9 building under strong earthquake is made. Three dimension structural nonlinear analysis and performance estimate programme Perform-3D is used to establish the calculatrion model. FEMA beam, shear strength section are used to set up the frame beam element modal; Moment plastic hinge, shear plastic hinge and elastic beam section are used to set up the link beam element modal; FEAM column and shear strength section are used to set up the column element modal; fiber wall element is used to model the sheae wall. Performances of the structure under strong earthquake are analysed. Numerical calculation results indicate that the structure design satisfies the preestablished performance targets.

Stability of Road Embankments in Soft Clay

1974 ◽  
Vol 11 (1) ◽  
pp. 72-88 ◽  
Author(s):  
Kaare Flaate ◽  
Terje Preber
Keyword(s):  
Shear Strength ◽  
Stability Analysis ◽  
Factor Of Safety ◽  
Soft Clay ◽  
Total Stress ◽  
Routine Procedure ◽  
The One ◽  
Marine Clays

Slides in soft marine clays frequently occur during construction of road embankments in Norway. This paper outlines the routine procedure used for a stability analysis of such embankments, based on a total stress concept. Using these procedures, eight slides were investigated, and it was found that the minimum factor of safety obtained could give a too conservative picture of the actual conditions. The minimum factor of safety, which is the one normally used, varied between 0.73 and 1.10. Taking all uncertainties into consideration, an analysis based on a total stress concept as outlined herein must be considered acceptable. The study gives no basis for evaluating the accuracy of the measured shear strength values.

scholarly journals Structural Response to Blast Loading: The Effects of Corrosion on Reinforced Concrete Structures

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Hakan Yalciner
Keyword(s):  
Reinforced Concrete ◽  
Concrete Strength ◽  
Plastic Hinge ◽  
Structural Response ◽  
Blast Loading ◽  
Structural Safety ◽  
Terrorist Attacks ◽  
Important Place ◽  
The One ◽  
The Impact

Structural blast design has become a necessary part of the design with increasing terrorist attacks. Terrorist attacks are not the one to make the structures important against blast loading where other explosions such as high gas explosions also take an important place in structural safety. The main objective of this study was to verify the structural performance levels under the impact of different blast loading scenarios. The blast loads were represented by using triangular pulse for single degree of freedom system. The effect of blast load on both corroded and uncorroded reinforced concrete buildings was examined for different explosion distances. Modified plastic hinge properties were used to ensure the effects of corrosion. The results indicated that explosion distance and concrete strength were key parameters to define the performance of the structures against blast loading.

scholarly journals CONTRIBUTION OF CONCRETE TO SHEAR STRENGTH OF RC BEAMS FAILING IN SHEAR

2013 ◽  
Vol 19 (3) ◽  
pp. 400-408 ◽  
Author(s):  
Guray Arslan ◽  
Zekeriya Polat
Keyword(s):  
Shear Strength ◽  
Shear Failure ◽  
Plastic Hinge ◽  
Transverse Reinforcement ◽  
Rc Beams ◽  
Earthquake Resistant ◽  
Earthquake Resistant Structures ◽  
Shear Failures ◽  
Beam Plastic Hinge ◽  
Shear Demand

Reinforced concrete (RC) beams with light transverse reinforcement are vulnerable to shear failure during seismic response. In order to prevent brittle shear failures at beam plastic hinge regions of earthquake-resistant structures, the Turkish Earthquake Code and ACI318 require the use of sufficient transverse reinforcement to resist the total expected shear demand. These codes tend to be excessively conservative and, in some cases, the contribution of the concrete to the shear strength is neglected. The aim of this study is to investigate the contribution of concrete to shear strength of RC beams failing in shear experimentally. The beams were tested under monotonically increasing reversed cyclic loading to determine the concrete contribution to shear strength. It is observed that the concrete contribution to the shear strength at ultimate state ranges from 18% to 69% of the ultimate strength.

scholarly journals Seismic collapse assessment of new European single-story RC precast buildings with weak connections

2020 ◽  
Vol 18 (15) ◽  
pp. 6661-6686
Author(s):  
Maddalena Cimmino ◽  
Gennaro Magliulo ◽  
Gaetano Manfredi
Keyword(s):  
Shear Strength ◽  
Failure Modes ◽  
Plastic Hinge ◽  
Concrete Cover ◽  
Eurocode 8 ◽  
Structural Level ◽  
Seismic Safety ◽  
Strength Failure ◽  
Precast Buildings ◽  
Lateral Displacements

Abstract Capacity design, according to the modern seismic building codes, requires the application of specific rules and construction details in order to prevent brittle failure modes at material, element and structural level. In particular, with reference to single-story precast reinforced concrete structures with columns joined by pinned beams, the Italian seismic building code, following the Eurocode 8 general principles, requires that beam-to-column connection should be designed in order to avoid the connection failure before the formation of the plastic hinge at the column base. However, no specific details are provided in order to reach such a performance. Recent European earthquakes showed that seismic performance of beam-to-column dowel connections can be very poor. Hence, for European typical dowel beam-to-column connections, this study aims to investigate: (a) possible connection configurations obtained according to seismic design; (b) possible failure modes involving connection elements (steel dowel, transversal steel reinforcement, dowel concrete cover); (c) how available formulations are able to describe such failure modes and the related shear strength; (d) influence of connection failure on the global seismic safety at collapse of new designed single-story RC precast buildings. The reference buildings and beam-to-column connections are designed considering different geometrical layouts of the primary structure and different seismic hazard levels, i.e. four sites and two soil types. Structural capacity is estimated considering global, i.e. related to column plastic hinge degradation measured in terms of top lateral displacements, and local, i.e. related to connection shear strength, failure modes. Nonlinear multi-stripe analyses are performed for the seismic assessment.

scholarly journals Shear Strength of Reinforced Concrete Columns Retrofitted by Glass Fiber Reinforced Polyurea

2020 ◽  
Vol 6 (10) ◽  
pp. 1852-1863
Author(s):  
Jun-Hyeok Song ◽  
Eun-Taik Lee ◽  
Hee-Chang Eun
Keyword(s):  
Shear Strength ◽  
Reinforced Concrete ◽  
Glass Fiber ◽  
Plastic Hinge ◽  
Compressive Load ◽  
Shear Capacity ◽  
Dissipated Energy ◽  
Fiber Reinforced ◽  
Lateral Confinement ◽  
Glass Fiber Reinforced

Aged structures and structures constructed based on outdated non-seismic design codes should be retrofitted to enhance their strength, ductility, and durability. This study evaluates the structural performance of reinforced concrete (RC) columns enhanced via polyurea or glass fiber reinforced polyurea (GFRPU) strengthening. Four RC column specimens, including a reference specimen (an unstrengthened column), were tested to evaluate the parameters of the strengthening materials and the strengthened area. The tests were carried out under a combined constant axial compressive load and quasi-static cyclic loading. The experimental results show that the composite strengthening provides lateral confinement to the columns and leads to enhanced ductility, shear-resistance capacity, and dissipated energy. The shear strength provided by the composites depends on the degree of lateral confinement achieved by the composite coating. The specimens finally failed through the development of diagonal tension cracks within the potential plastic hinge regions. The specimen treated with GFRPU strengthening showed greater strength and dissipated more energy than the specimen treated with polyurea strengthening. Furthermore, by modifying ATC-40, this study proposed an equation to estimate the shear capacity provided by the composites.

scholarly journals Photoreactive UV-Crosslinkable Acrylic Pressure-Sensitive Adhesives (PSA) Containing Multifunctional Photoinitiators

Polymers ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 4413
Author(s):  
Marcin Bartkowiak ◽  
Zbigniew Czech ◽  
Hyun-Joong Kim ◽  
Gyu-Seong Shim ◽  
Małgorzata Nowak ◽  
...  
Keyword(s):  
Shear Strength ◽  
Ultraviolet Radiation ◽  
Type I ◽  
Type Ii ◽  
Pressure Sensitive Adhesives ◽  
Crosslinking Process ◽  
Pressure Sensitive ◽  
Peel Adhesion ◽  
The One ◽  
Uv Technology

The use of ultraviolet radiation (UV) technology for the crosslinking of acrylic pressure-sensitive adhesives (PSA) is the one of various crosslinking methods, being the alternative to the conventional crosslinking process of solvent-based acrylic systems. It also requires a photoinitiator to absorb the impinging UV and induce photocrosslinking. As previously mentioned, a photoinitiator is one of the important and necessary components in UV-inducted crosslinking of acrylic pressure-sensitive adhesives. The activity of multifunctional conventional saturated photoinitiators of type I and type II, especially benzophenone-based in the photoreactive UV-crosslinkable acrylic PSA was described. The effect of the multifunctional type-II photoinitiators on the acrylic PSA, such as tack, peel adhesion and shear strength were summarized.

scholarly journals Experimental Study on the Seismic Behaviour of Reinforced Concrete Bridge Piers Strengthened by BFRP Sheets

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Yong Li ◽  
Meng-Fei Xie ◽  
Jing-Bo Liu
Keyword(s):  
Reinforced Concrete ◽  
Seismic Performance ◽  
Plastic Hinge ◽  
Seismic Retrofitting ◽  
Bridge Piers ◽  
Strengthening Effect ◽  
Basalt Fibre ◽  
Seismic Behaviour ◽  
Ductility Capacity ◽  
Existing Bridges

With the continuous development of the ductility capacity concept for seismic design of bridges, the ductility capacity of many existing bridges does not meet the requirements of the current code for seismic performance because of the low reinforcement ratio and reinforcement corrosion of reinforced concrete (RC) piers. Because of their superior mechanical properties and low price, basalt fibre-reinforced polymer (BFRP) sheets have potential application in the seismic retrofits field of existing bridges. To study the seismic strengthening effect of RC pier columns, scaled specimens with standard reinforcement ratios, with low reinforcement ratios according to the past code and with corroded reinforcements, were designed and manufactured and then wrapped and pasted with BFRP sheets on the plastic hinge areas. Pseudostatic tests were conducted to verify the seismic performance of the strengthened and unstrengthened specimens. Experimental results showed that the ultimate flexural capacity, deformation capacity, and energy dissipation capacity of strengthened RC pier columns were superior. Especially for strengthened specimens with low reinforcement ratios or corrosion reinforcement, their seismic performance could rival than that of columns with standard reinforcement ratios, which showed the advantage of BFRP sheets in the seismic retrofitting of existing bridge piers.

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