scholarly journals Experimental Investigation on Seismic Behaviours of Reinforced Concrete Columns under Simulated Acid Rain Environment

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Hao Zheng ◽  
Shansuo Zheng ◽  
Yixin Zhang ◽  
Yonglong Cai ◽  
Ming Ming ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Energy Dissipation ◽  
Acid Rain ◽  
Carrying Capacity ◽  
Simulated Acid Rain ◽  
Deformation Capacity ◽  
Load Carrying Capacity ◽  
Rc Column ◽  
Visual Damage ◽  
Load Carrying

The purpose of this paper was to systematically investigate the influence of acid rain environments on the seismic behaviour of a reinforced concrete (RC) column. Six RC column specimens with shear span ratios of 2.84 were tested under low cyclic reversed loads after being subjected to accelerated corrosion tests in an artificial climate. The corrosion level and stirrup ratio were used as the control variables. The corrosion ratios of the longitudinal rebars ranged from 0 to 13.17%, and the corrosion ratios of the stirrups varied from 0 to 6.75%. The seismic behaviours of the column specimens were analysed with respect to visual damage, failure mode, hysteresis behaviour, load-carrying capacity, deformation capacity, stiffness degradation, and energy dissipation behaviour. The test results showed that the appearance characteristics of the six column specimens exhibited varying degrees of visual damage as a result of the simulated acid rain exposure. All six specimens were dominated by similar flexural-shear failures under low cyclic reversed loads, regardless of the distinctions in the corrosion levels or stirrup ratios. For the specimens with the same ratios of stirrup, as the corrosion level increased, the load-carrying capacity, deformation capacity, stiffness, and energy dissipation capacity were continuously decreased. For the specimens with the same levels of corrosion, the higher the stirrup ratio was, the stronger the restraint effect of the stirrups on the concrete, and the seismic behaviours of the specimens were obviously improved.

scholarly journals Seismic Upgrading of RC Wide Beam–Column Joints Using Steel Jackets

Buildings ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 203
Author(s):  
Giuseppe Santarsiero ◽  
Angelo Masi
Keyword(s):  
Reinforced Concrete ◽  
Energy Dissipation ◽  
Cyclic Loading ◽  
Carrying Capacity ◽  
Load Carrying Capacity ◽  
Seismic Capacity ◽  
Seismic Behaviour ◽  
Wide Beam ◽  
Rc Frames ◽  
Load Carrying

This study is devoted to experimentally investigate the seismic behaviour of reinforced concrete (RC) wide beam–column joints equipped with a steel jacketing seismic strengthening solution. To this end, three identical full-scale specimens have been tested under cyclic loading, one in the as-built condition and two after the application of the strengthening solutions. Details of selected solutions are described in the paper along with the experimental results which confirm how the application of simple and feasible steel interventions can effectively improve the seismic capacity of wide beam–column connections in RC frames, especially in terms of lateral load carrying capacity and energy dissipation.

scholarly journals A Detailed Experimental Study on The Flexural Behaviour of Concrete Filled Steel Tube Beams

2018 ◽  
pp. 196-203
Author(s):  
Shaik Heena ◽  
Syed Rizwan ◽  
A.B.S. Dadapeer
Keyword(s):  
Reinforced Concrete ◽  
Carrying Capacity ◽  
Ultimate Load ◽  
Steel Tube ◽  
Deformation Capacity ◽  
Load Carrying Capacity ◽  
Shear Connector ◽  
Steel Tubes ◽  
Load Carrying ◽  
Concrete Filled Steel Tubes

Concrete filled steel tubes (CFST) member have many advantages compared with the ordinary structural member made of steel or reinforced concrete. One of the main advantages is the interaction between the steel tube and concrete. Concrete delays the steel tube’s local buckling, whereas the steel tube confines the concrete and thereby increases the concrete’s strength. CFSTs are economical and permit rapid construction because the steel tube serves as formwork and reinforcement to the concrete fill, negating the need for either. The deformation capacity of the system is increased by the combined action of the concrete fill with the thin, ductile steel tube. The concrete fill significantly increases inelastic deformation capacity and the compressive stiffness and load capacity of the CFST member. In building construction concrete filled steel tubes are very widely used for columns in combination with steel or reinforced concrete beam. In this work totally 9 specimens were tested out of which 3 specimens were empty steel tubes and remaining 6 specimens were concrete filled with different bonding techniques. As it is prefabricated time consumption will be less in construction practice and due to confinement more ductility is expected which is very useful in earthquake resistant structures. Load carrying capacity of CFST almost doubled in comparison with empty steel tubes. Ultimate load carrying capacity of concrete filled steel tube beams almost doubled compared to empty steel tubes. Compared to empty steel tubes, strength increase of 67.19%, 97.48% and 114.84% was observed in normal CFST, CFST with sand blasting and CFST with diagonal shear connector beams respectively. Average ultimate load of EST was 105.66kN whereas average load of CFSTB, CFSTBWSB and CFSTBWDSC was 176.66, 208.66 and 227kN respectively. The maximum load was taken by the specimen CFSTBWDSC – 03 which was 231kN, it may be because of presence of diagonal shear connector inside the tube.

Experimental Study on Flexural Strength of Reinforced Concrete Beam Exposed to Acid Deposition in the Laboratory

2011 ◽  
Vol 94-96 ◽  
pp. 1494-1499
Author(s):  
Ying Fang Fan ◽  
Da Wei Wang ◽  
Shi Yi Zhang
Keyword(s):  
Reinforced Concrete ◽  
Acid Rain ◽  
Carrying Capacity ◽  
Concrete Beams ◽  
Reinforced Concrete Beams ◽  
Flexural Behavior ◽  
Load Carrying Capacity ◽  
The Real ◽  
Artificial Rainfall ◽  
Load Carrying

In this study, the flexural behavior of the reinforced concrete beams attacked by acid rain environment is investigated. The objective is to discover the deterioration mechanism of the concrete beams servicing in the acid rain environment. An artificial rainfall device was designed. Eleven reinforced concrete beams, 120mm×200mm in cross-section were prepared in the laboratory. Three accelerating corrosion methods, which inclusive of immersion method, dry-wet cycle method, and artificial rainfall method, were applied to simulate the action of the real acid rain respectively. The acid solutions with pH level 1.5 and 2.5 were prepared by the mixture of sulfate and nitric acid solution respectively. One of the beams was tested in the natural condition to serve as reference; the remaining ten beams were tested after being exposed to the simulated acid environments for certain periods. Ultrasonic technology was applied to evaluate the damage depth and the compressive strength of the concrete. Dynamic test was applied to estimate the integrity of the beam. Three-point bending tests were performed to investigate the load carrying capacity of the beams. Mechanical properties of concrete and load carrying capacity of the beams exposed to different accelerated corrosion methods are obtained and compared. It is illustrated that the designed artificial device is efficient to simulate the real acid rainfall. It is shown that the strength of concrete, frequency and ultimate load of the beams, have a direct relationship to the damage degree of the beams.

scholarly journals Experimental study on the behavior of eccentrically compressed reinforced concrete columns strengthened with CFRP composite sheets

2021 ◽  
Vol 15 (4) ◽  
pp. 172-181
Author(s):  
Trung Hieu Nguyen ◽  
Xuan Dat Pham ◽  
Khuong Duy Tran
Keyword(s):  
Experimental Study ◽  
Reinforced Concrete ◽  
Carrying Capacity ◽  
Column Height ◽  
Strengthening Effect ◽  
Load Carrying Capacity ◽  
Rc Columns ◽  
Cfrp Sheets ◽  
Rc Column ◽  
Load Carrying

Strengthening of reinforced concrete (RC) columns is needed when the actual load-carrying capacity of the columns does not reach the required level due to either structural deterioration or increasing acting loads. This experimental study aims to evaluate the strengthening effect on the eccentrically-compressed RC columns using Carbon fiber reinforced polymer (CFRP) sheets, that confine around the column cross-section. Three RC column specimens with the same geometrical dimensions, reinforcement detailing, and concrete compressive strength were cast and tested in the current experimental investigation. One RC column without being strengthened is referred as the control specimen whereas two other RC columns were partially strengthened by CFRP sheets. All three RC columns were axially loaded with the same initial eccentricity e0 of 80 mm. Based on the test results such as the ultimate load-carrying capacity, the load-rotation relationship, and load-curvature at the middle of column height, the effectiveness of the strengthening technique is discussed.

Analysis of Seismic Performance of RC Frames with Centrally Reinforced Columns

2013 ◽  
Vol 671-674 ◽  
pp. 1319-1323
Author(s):  
Zi Xue Lei ◽  
Yu Hang Han ◽  
San Sheng Dong ◽  
Jun Qing Guo
Keyword(s):  
Seismic Performance ◽  
Cross Sections ◽  
Carrying Capacity ◽  
Pushover Analysis ◽  
Seismic Load ◽  
Load Carrying Capacity ◽  
Rc Columns ◽  
Rc Column ◽  
Rc Frames ◽  
Load Carrying

A centrally reinforced column is a new type of RC columns, formed by providing a reinforcement skeleton at the central part of the cross section of an ordinary RC column. Tests have shown that as compared with an ordinary RC column, this type of columns has a higher load carrying capacity and ductility. From the pushover analysis of a frame composed of ordinary RC columns and one consisting of centrally reinforced columns, their seismic performance under seismic load of 9-degree intensity was studied according to Chinese code, including target displacements, story-level displacements, interstory drifts, appearance and development of plastic hinges. The results indicate that although the dimensions of cross sections of columns in the frame with centrally reinforced columns are smaller than those of the ordinary frame, the former still has a higher overall load carrying capacity and seismic performance than the latter.

scholarly journals Strengthening of Reinforced Concrete Beams Subjected to Concentrated Loads

2022 ◽  
Author(s):  
Paolo Foraboschi
Keyword(s):  
Reinforced Concrete ◽  
Carrying Capacity ◽  
Concrete Beams ◽  
Shear Capacity ◽  
Reinforced Concrete Beams ◽  
Load Carrying Capacity ◽  
Reinforced Concrete Structure ◽  
Concentrated Loads ◽  
Concentrated Load ◽  
Load Carrying

Renovation, restoration, remodeling, refurbishment, and retrofitting of build-ings often imply modifying the behavior of the structural system. Modification sometimes includes applying forces (i.e., concentrated loads) to beams that before were subjected to distributed loads only. For a reinforced concrete structure, the new condition causes a beam to bear a concentrated load with the crack pattern that was produced by the distributed loads that acted in the past. If the concentrated load is applied at or near the beam’s midspan, the new shear demand reaches the maximum around the midspan. But around the midspan, the cracks are vertical or quasi-vertical, and no inclined bar is present. So, the actual shear capacity around the midspan not only is low, but also can be substantially lower than the new demand. In order to bring the beam capacity up to the demand, fiber-reinforced-polymer composites can be used. This paper presents a design method to increase the concentrated load-carrying capacity of reinforced concrete beams whose load distribution has to be changed from distributed to concentrated, and an analytical model to pre-dict the concentrated load-carrying capacity of a beam in the strengthened state.

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