scholarly journals Investigation of Residual Bearing Capacity of Corroded Reinforced Concrete Short Columns under Impact Load Based on Nondestructive Testing

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Guorui Sun ◽  
Yi Zhang ◽  
Yubin Tian ◽  
Lizhuang Bo ◽  
Jiyang Shen ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Nondestructive Testing ◽  
Corrosion Rate ◽  
Bearing Capacity ◽  
Impact Load ◽  
Influence Factors ◽  
Impact Loads ◽  
Damage Factor ◽  
Rc Structures ◽  
Short Columns

This paper investigates the damage and residual bearing capacity of corroded reinforced concrete (RC) short columns after impact and presents a method for evaluating the residual bearing capacity of RC short columns by nondestructive testing. Firstly, accelerated corrosion test and drop hammer impact test were carried out to obtain specimens under different impact loads and corrosion rates. Then, the damage caused by corrosion and impact loads was evaluated by supersonic wave aided nondestructive test. Through the damage factor, the influence of corrosion rate and impact loads on the specimen was revealed, and the calculation method of corrosion rate and impact velocity was proposed. Finally, according to the bearing capacity test results, the influence factors of reinforcement, concrete, and impact were introduced into the bearing capacity calculation equation. Considering the relationship between the residual bearing capacity of RC short columns and the damage factor, an improved formula for calculating the residual bearing capacity of corroded RC short columns under impact loads was proposed. This work lays the foundation for further research on mechanical properties of corroded RC structures under impact loads.

scholarly journals Ultimate Compressive Strains and Reserves of Bearing Capacity of Short RC Columns with Basalt Fiber

2021 ◽  
Vol 11 (16) ◽  
pp. 7634
Author(s):  
Aleksandr V. Shilov ◽  
Alexey N. Beskopylny ◽  
Besarion Meskhi ◽  
Dmitry Mailyan ◽  
Dmitry Shilov ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Basalt Fiber ◽  
Lightweight Aggregate ◽  
Short Fiber ◽  
Hydraulic Press ◽  
Steel Reinforcement ◽  
Fiber Reinforced Concrete ◽  
Material Consumption ◽  
Short Columns

Increasing the bearing capacity of reinforced concrete structures, reducing material consumption, and ensuring quality are critical in modern construction. The article presents an experimental study of the ultimate compressive strains of short fiber basalt reinforced concrete columns and provides recommendations for increasing the bearing capacity using steel reinforcement bars with greater strength. The columns were tested in an upright position using a hydraulic press. Strains were measured with dial indicators and a strain gauge station. It was shown that the addition of 10% coarse basalt fiber increased the ultimate compressibility of concrete on ordinary crushed stone by 19.8%, and expanded clay concrete by 26.1%, which led to the strain hardening of concrete under compression by 9.0% and 12%, respectively. Ultimate compressive strains in fiber-reinforced concrete short columns with combined reinforcement increased 1.42 times in columns on a lightweight aggregate and 1.19 times on heavy aggregate. An increase in the ultimate compressibility of concrete makes it possible to use steel reinforcement with greater strength in compressed elements as the concrete crushing during compression occurs primarily due to the reaching of critical values by tensile stresses in the transverse direction. This makes it possible to manufacture structures with a higher load-bearing capacity and less material consumption. A practical example of the application of the proposed approach is given.

scholarly journals Influence Factors Analysis of RC Beams under Falling Weight Impact Based on HJC Model

2018 ◽  
Vol 2018 ◽  
pp. 1-16 ◽  
Author(s):  
Xiaohong Long ◽  
Ahmed Turgun ◽  
Rong Yue ◽  
Yongtao Ma ◽  
Hui Luo
Keyword(s):  
Finite Element ◽  
Impact Load ◽  
Influence Factors ◽  
Response Analysis ◽  
Impact Loads ◽  
Rc Beams ◽  
Element Analysis ◽  
Structure Component ◽  
Weight Impact ◽  
Falling Weight

Impact loads may cause serious or even fatal damage to the structure (component), in most existing specifications in China, and there are no special terms that take impact load into consideration. So, the response analysis of the structure (component) under impact loads is very important. In this paper, the sensitivity analysis was conducted for the 22 parameters of the Holmquist–Johnson concrete (HJC) constitutive model of concrete, and the sensitive parameters of the HJC model are identified with A, B, G, Pl, μl, and fc respectively. LS-DYNA nonlinear transient finite element analysis code was used for this paper. Based on the validation of finite element modeling and choosing midspan deflection of RC beams and impact loads as response indices, some influencing factors on RC beams under falling weight impact were investigated, such as the mass and speed of falling weight, impact position, the strength of concrete and rebar, longitudinal reinforcement ratio, and the span of the beam.

scholarly journals A new testing method for textile reinforced concrete under impact load

2018 ◽  
Vol 199 ◽  
pp. 11010 ◽  
Author(s):  
Marcus Hering ◽  
Manfred Curbach
Keyword(s):  
Reinforced Concrete ◽  
Large Scale ◽  
Impact Load ◽  
Impact Resistance ◽  
Concrete Structures ◽  
Reinforced Concrete Structures ◽  
Impact Loads ◽  
Textile Reinforced Concrete ◽  
Reinforcement Structure ◽  
Testing Method

Textile reinforced concrete, especially textile reinforced concrete with carbon fibres, was already been used for strengthening steel reinforced concrete structures under static loads up to now. The question is if the composite can also be used for strengthening structures against impact loads. The main goal of a current research project at the Technische Universität Dresden is the development and characterization of a reinforcement fabric with optimized impact resistance. But there is a challenge. There is the need to find the best combination of fibre material (glass, carbon, steel, basalt, …) and reinforcement structure (short fibres, 2D-fabrics, 3D-fabrics, …), but testing the large number of possible combinations is not possible with the established methods. In general, large-scale tests are necessary which are very expensive and time consuming. Therefore, a new testing method has been developed to deal with this large number of possible combinations of material and structural experiments. The following paper describes this new testing method to find the best fabric reinforcement for strengthening reinforced concrete structures against impact loads. The testing devise, which is located in the drop tower facility at the Otto Mohr Laboratory, and the test set-up are illustrated and described. The measurement equipment and the methods to evaluate the experimental results are explained in detail.

Ultimate Bearing Capacity Analysis of Axially Compressive Circular Steel Tube Columns Filled with Bar-Reinforced Concrete

2011 ◽  
Vol 94-96 ◽  
pp. 1205-1210
Author(s):  
Zhao Liu ◽  
Jun Hai Zhao
Keyword(s):  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Steel Tube ◽  
Ultimate Bearing Capacity ◽  
Strength Theory ◽  
Principal Stresses ◽  
Unified Strength Theory ◽  
Short Columns ◽  
Circular Steel Tube ◽  
Circular Bar

The mechanical behavior and ultimate bearing capacity of the circular bar-reinforced concrete filled steel tube (BRCFST) short columns under axial compression are analyzed in this paper based on the unified strength theory. Considering the restriction effect of steel tube and hoop bar on concrete, the calculation formula of bearing capacity of the column is deduced. Parametric studies are carried out to evaluate the effects of intermediate principal stresses, diameter-thickness ratio of steel tube and the stirrup ratio on the bearing capacity of the column. A good agreement is reached by comparing the results calculated by the formula with the test results. It is concluded that the unified strength theory is applicable in the theoretical analyses of the BRCFST columns.

Bearing Capacity of the Corrosion Reinforced Concrete Axial Compression Members

2012 ◽  
Vol 430-432 ◽  
pp. 1830-1833 ◽  
Author(s):  
Guo Ye Wang ◽  
Zhi Pan Wang ◽  
Yu Yin ◽  
Feng Chi Wang
Keyword(s):  
Reinforced Concrete ◽  
Corrosion Rate ◽  
Bearing Capacity ◽  
Axial Compression ◽  
Protective Layer ◽  
Steel Corrosion ◽  
Integral Model ◽  
Compression Members ◽  
Expansion Force ◽  
The Relationship

based on the relationship between steel rust expansion force and the amount of corrosion, regarding reinforced concrete as a general continuum with the use of integral model, the finite element analysis models of axial compressive members were set up. Concrete units cracking and crushing were considered by the methods of multi-axial stress William-Warnke five-parameter failure criteria and fracture dispersion mode. For axial compression corroded reinforced concrete structures, firstly under the action of rust expansion force produced by steel corrosion, cracks begin to occur around the steel, then column corner steel cracks emerge by the direction of the protective layer and progressively extend to the entire protective layer. With the increasing of the steel corrosion rate, the ultimate bearing capacity reduces. According to the relationship of the corrosion rate and the capacity reduction, a simple method of calculation was established for corrosion axis of the bearing capacity of compression members.

Laboratory Tests and Numerical Simulations of CFRP Strengthened RC Pier Subjected to Barge Impact Load

2015 ◽  
Vol 15 (02) ◽  
pp. 1450037 ◽  
Author(s):  
Yanyan Sha ◽  
Hong Hao
Keyword(s):  
Reinforced Concrete ◽  
Structural Damage ◽  
Impact Load ◽  
Numerical Models ◽  
Impact Resistance ◽  
Bridge Piers ◽  
Impact Loads ◽  
Bridge Structures ◽  
Cfrp Composite ◽  
Vessel Impact

Bridge piers are designed to withstand not only axial loads of superstructures and passing vehicles but also out-of-plane loads such as earthquake excitations and vessel impact loads. Vessel impact on bridge piers can lead to substantial damages or even collapse of bridge structures. An increasing number of vessel collision accidents have been reported in the past decade. A lot of researches have been conducted for predicting barge impact loads and calculating structural responses. However, in practice it is not possible to design bridge structures to resist all levels of barge impact loads. Moreover, with an increasing traffic volume and vessel payload in some waterways, the bridge piers designed according to previous specifications might not be sufficient to resist the current vessel impact loads. Therefore, strengthening existing bridge piers are sometimes necessary for protecting structures from barge impact. Carbon fiber reinforced polymer (CFRP) has been widely used in strengthening reinforced concrete structures under impulsive loadings. It is an effective material which has been proven to be able to increase the flexural strength of structures. In this study, CFRP composites are used to strengthen reinforced concrete piers against barge impact loads. Pendulum impact tests are conducted on scaled pier models. Impact force and pier response with and without CFRP strengthening are compared. The effectiveness of using CFRP strengthening the pier model is observed. In addition, numerical models of the bridge piers are developed and calibrated with experimental results. Parametric simulations of barge impacting on piers with or without CFRP strengthening are carried out. The results show that compared with unstrengthened pier, CFRP composite strengthened bridge pier has a higher impact resistance capacity and hence endures less structural damage under the same barge impact load. The effectiveness of CFRP strengthening with different CFRP thickness, CFRP strength and bond strength between the pier and the CFRP composite are also discussed.

Research of Compression Bearing Capacity of Steel Reinforced Concrete Short Column Replaced by C-BAR

2013 ◽  
Vol 438-439 ◽  
pp. 519-521
Author(s):  
Cheng Zhu Qiu
Keyword(s):  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Axial Compression ◽  
Steel Reinforced Concrete ◽  
Short Column ◽  
Reinforcing Bar ◽  
Short Columns

t is essential to study the performance of reinforced concrete short column. In this paper, the main reinforcements and hoopings in short columns were replaced by C-BAR reinforcements, the regularity of reinforcing bar replaced by C-BAR reinforcements was summarized. The results show that the axial compression bearing capacity of concrete short column is increased.

Scale-model testing of reinforced concrete under impact loading conditions

1989 ◽  
Vol 16 (4) ◽  
pp. 459-466 ◽  
Author(s):  
J. A. Sato ◽  
F. J. Vecchio ◽  
H. M. Andre
Keyword(s):  
Reinforced Concrete ◽  
Key Words ◽  
Impact Loading ◽  
Impact Load ◽  
Scaling Theory ◽  
Scale Model ◽  
Reinforced Concrete Structures ◽  
Impact Loads ◽  
Test Program ◽  
Load Conditions

Aspects of scaling theory relating to the response of reinforced concrete structures under impact load conditions are reviewed. Details for modelling concrete and reinforcement, to be consistent with similitude requirements, are also discussed. A test program is described in which models of varying size were constructed, drop tested, and compared with prototype response. An analysis of the test data is made, indicating that, within certain limitations, the predictions of scaling theory are applicable to reinforced concrete subjected to extreme impact loads. Key words: cracking, impact, loads, modelling, reinforced concrete, scaling, stresses, structures, tests.

Recommendations for Designing Reinforced Concrete Beams Against Low Velocity Impact Loads

2018 ◽  
Vol 18 (09) ◽  
pp. 1850104 ◽  
Author(s):  
Piyapong Wongmatar ◽  
Chayanon Hansapinyo ◽  
Vanissorn Vimonsatit ◽  
Wensu Chen
Keyword(s):  
Reinforced Concrete ◽  
Impact Load ◽  
Reaction Force ◽  
Reinforced Concrete Beams ◽  
Low Velocity Impact ◽  
Inertia Force ◽  
Impact Loads ◽  
Rc Beams ◽  
Low Velocity ◽  
Velocity Impact

This study investigates the behaviors of simply supported reinforced concrete (RC) beams subjected to impact loads. A numerical model of RC beams has been calibrated and a total of 18 RC beams with varying longitudinal reinforcement, transverse shear reinforcement, span and effective depth are investigated, subjected to different input impact energy. It is found that inertia force plays an important role in resisting an impact load at the starting time. The slenderness of the beam can cause increased downward reaction force and also amplifies the upward reaction force. Based on the numerical results, recommendations are made for designing RC beams under low velocity impact load. A formula is derived to predict the maximum mid-span deflection under low velocity impact load with respect to the kinetic energy and static bending capacity. The maximum spacing and the diameter of stirrups are also recommended so as to avoid the brittle failure under impact load.

scholarly journals Numerical Simulation of Corroded Reinforced Concrete Beam Strengthened by a Steel Plate with Different Strengthening Schemes

2020 ◽  
Vol 2020 ◽  
pp. 1-19
Author(s):  
Huang Tang ◽  
Jianxin Peng ◽  
Linfa Xiao ◽  
Xinhua Liu ◽  
Jianren Zhang
Keyword(s):  
Reinforced Concrete ◽  
Corrosion Rate ◽  
Bearing Capacity ◽  
Steel Plate ◽  
Steel Strip ◽  
Reinforced Concrete Beam ◽  
Constitutive Law ◽  
Bottom Surface ◽  
Bond Slip ◽  
Tension And Compression

This paper proposes 3D nonlinear finite element (FE) models to predict the response of corroded reinforced concrete (RC) beam strengthened using a steel plate. Five FE models are developed based on the tests carried out by the authors in a previous investigation, in which three models are used to simulate the corroded RC beams with different schemes. The FE models use the coupled damaged-plasticity constitutive law for concrete in tension and compression and consider the bond-slip between the corroded tensile steel bar and concrete. The cohesive element is also used to model the cohesive bond between the steel plate and concrete. The FE results of load-deflection and the crack distribution are compared with the test data. The FE results are consistent with the test results. The influence of the thickness of the steel plate, the thickness, and location of the U-shaped steel strip on the bearing capacity of the strengthened corroded beam is analyzed through FE models. The results show that the thickness of the steel plate on the bottom surface should not exceed 4 mm for the flexure-strengthened and combined strengthened beams with a 10% corrosion rate. It is most reasonable to improve the bearing capacity using the 3 mm and 2 mm of thick U-shaped steel strips for the shear-strengthened and combined strengthened beams, respectively. The most reasonable location of the U-shaped steel plate is at the end of the steel plate for beams with a 10% corrosion rate.

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