Structural Defects of Existing RC Buildings in Eskisehir Province

2011 ◽  
Vol 147 ◽  
pp. 145-148 ◽  
Author(s):  
A.Emre Cengiz ◽  
Yücel Güney ◽  
Onur Kaplan ◽  
Ahmet Topçu ◽  
Yunus Özçelikörs ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Concrete Strength ◽  
Steel Reinforcement ◽  
Structural Defects ◽  
Existing Buildings ◽  
Rc Buildings ◽  
Short Column ◽  
Adjacent Buildings ◽  
Long Span ◽  
Lateral Reinforcement

In this study, structural defects of existing 709 reinforced concrete (RC) buildings in Eskisehir Province were represented. Structural defects such as gaps between adjacent buildings, strong beam-weak column, mezzanine floor, short column, corner column, discontinuous frame, anchorage beams, long span, segregation, corrosion, inconvenient column/beam lateral reinforcement, low concrete strength and inconvenient steel reinforcement were determined in the study. It was determined that %35 of existing buildings have discontinuous frame, %16 of them have long span problem. It was also observed that nearly %40 of the buildings have no column/beam lateral reinforcement and %70 of them have inadequate gaps.

scholarly journals Forensic to the Reinforced Concrete (RC) Structures at Library

2020 ◽  
Vol 19 (1) ◽  
pp. 6-14
Author(s):  
Tang Hing Kwong ◽  
Rudy Tawie ◽  
Siti Rozana Romali
Keyword(s):  
Reinforced Concrete ◽  
Crack Width ◽  
Concrete Strength ◽  
Reinforced Concrete Beam ◽  
Steel Reinforcement ◽  
Reinforced Concrete Structure ◽  
Rebound Hammer ◽  
Rc Structures ◽  
Three Samples ◽  
Eurocode 2

This Forensic project has been proposed to investigate the reinforced concrete structure defect at library. There were found 65 points cracks and 20 points spalling in library such as only at reinforced concrete beam and slab part in first floor. The total of cracks which crack width less than 0.25 mm is 63 points and the crack width between 0.25 mm to 5.00 mm is 2 points only. These cracks had categorized as fine cracks because the crack width not more than 5 mm. There was 21 samples Rebound Hammer test was random measured the existing concrete compressive strength of critical structures which six samples at beams, six samples at slabs, six samples at columns and three samples at staircase in library. The Rebound Hammer test shown that average mid-point strength at beam is 33 N/mm2, slab is 25 N/mm², column is 38 N/mm2 and staircase is 37 N/mm2 . Based on the Eurocode 2, the minimum grade concrete required is 25N/mm2 to do the design for reinforced concrete structures, which all the existing concrete strength were achieved the minimum concrete strength. Finally, the Orion software are used to analysis and determine the size of steel reinforcement, the design found the required bar size of steel reinforcement at the middle span or continuous support is 2T16 & 2T25 or 2T20 & 2T25 but the existing steel reinforcement is 2T12 and 2T20 which the existing steel reinforcement could not be sustained the big loading that applied on the library.

Confinement of reinforced concrete columns with fibre-reinforced composite sheets - an experimental study

1999 ◽  
Vol 26 (2) ◽  
pp. 226-241 ◽  
Author(s):  
M Demers ◽  
K W Neale
Keyword(s):  
Reinforced Concrete ◽  
Fibre Composite ◽  
Concrete Strength ◽  
Practical Interest ◽  
Plain Concrete ◽  
Concrete Columns ◽  
Steel Reinforcement ◽  
Structural Behaviour ◽  
Reinforced Concrete Columns ◽  
Reinforced Composite

The wrapping of fibre-reinforced composite sheets around concrete columns is a promising method for structural strengthening and repair. This rehabilitation technique is of practical interest, as the lay-up of the sheets is rather easy; it does not require specialized tools, and the epoxy resins employed cure at ambient temperatures. Here, results of an experimental investigation are reported for 16 round reinforced concrete columns 300 mm in diameter and 1200 mm high. These columns were confined by means of carbon-epoxy sheets and loaded concentrically in axial compression. The effects of various parameters on the structural behaviour of the confined concrete columns are investigated. These parameters included the concrete strength, longitudinal steel reinforcement, steel stirrups, steel corrosion, and concrete damage. The test results show that composite confinement can considerably enhance the structural performance of concrete columns, especially with regard to ductility. The potential to restore the full strength of severely damaged columns is also demonstrated, as retrofitted columns exhibit axial load carrying capacities equal or superior to those of undamaged columns, along with significant increases in ductility. The contribution of the transverse steel reinforcement is seen to be minimal, as long as the stirrup spacing is medium to large. For such cases tests on plain concrete cylinders are sufficient for further investigations of this retrofit method, as the key parameters which really affect strength and ductility are the concrete strength, composite fibre type, and sheet thickness.Key words: fibre composite sheets, confinement, concrete, column repair, rehabilitation, strengthening.

scholarly journals Experimental Behavior of Concrete Columns Confined by Transverse Reinforcement with Different Details

2020 ◽  
Vol 14 (1) ◽  
pp. 250-265 ◽  
Author(s):  
Mariateresa Guadagnuolo ◽  
Alfonso Donadio ◽  
Anna Tafuro ◽  
Giuseppe Faella
Keyword(s):  
Reinforced Concrete ◽  
Concrete Strength ◽  
Concrete Columns ◽  
Confined Concrete ◽  
Experimental Program ◽  
Transverse Reinforcement ◽  
Eurocode 8 ◽  
Strength Increase ◽  
Existing Buildings ◽  
Concrete Confinement

Introduction: Most of the existing reinforced concrete buildings often have columns with poor transverse reinforcement details. Models for computing the confined concrete strength were developed using experimental tests performed on specimens with transverse reinforcement typical of seismic design. The paper presents the results of an experimental program performed to investigate the effect of type, amount and pitch of transverse reinforcement on the behavior of confined concrete. Aim: The paper is also aimed at evaluating whether the current code models are suitable for estimating the confined strength of concrete in existing buildings. Methods: A total of 45 reinforced concrete columns with four volume ratios of transverse reinforcement were tested under axial loads. Type and pitch of transverse reinforcement typical of existing r/c buildings not designed according to seismic standards were considered. Therefore, columns reinforced by spiral and hoops with 135° or 90° hooks at the end are investigated for comparing their behavior. The confinement of spirals and hoops to core concrete is discussed as the amount of transverse and longitudinal reinforcement varies. Small increases in strength due to the concrete confinement were measured for hoop pitch of 150 mm (ranging between 2% and 7%), but also for hoops with 90° hook and pitch of 75 mm. Greater increments were obtained by spirals and hoops with 135° hook in the case of 75 mm pitch and when rhomboidal hoops or cross-ties were arranged in addition to the perimeter hoops. A comparison with some similar experimental results is also performed, achieving quite similar results. The mean experimental stress-strain curves are also analyzed. Results: The results show how the increase in concrete strength due to the confinement is more dependent on the transverse reinforcement pitch than the type and detail of transverse reinforcement or even less diameter of longitudinal bars. Finally, the experimental strength of confined concrete is then compared with the values provided by Eurocode 8 and the new Italian Building Code, showing that the higher the volumetric percentage of transverse reinforcement, the greater the overestimation of code models. Conclusion: An overestimation of codes up to 30% is assessed, systematically lower in the case of spirals, and higher in the case of hoops with 90° hooks at the end. The results highlight the need to develop specific equations to determine the strength increase due to the concrete confinement in the case of existing buildings with poor transverse reinforcement.

Nonlinear Finite Element Analysis of Corroded Reinforced Concrete Lock-Walls

2011 ◽  
Vol 101-102 ◽  
pp. 329-332
Author(s):  
Fu Lai Qu ◽  
Shun Bo Zhao ◽  
Zhi Mei Zhou ◽  
Baoan Yuan
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Finite Element Model ◽  
Concrete Strength ◽  
Element Model ◽  
Steel Reinforcement ◽  
Nonlinear Finite Element ◽  
Flexural Behavior ◽  
Element Analysis ◽  
Bond Slip

Reinforcement and concrete can work together to bear load in reinforced concrete structures, one of the main reasons is the relatively prefect bond between reinforcement and concrete. When steel reinforcement corrodes, the bond strength decreases and leads to the degradation of the reinforced concrete members. This paper built a finite element model by selecting appropriate stress-strain relationship of concrete and reinforcement, bond-slip relationship between concrete and corroded steel bars. The flexural behavior of corroded reinforced concrete lock-walls was analyzed by nonlinear finite element method. The calculated results were compared with the test results to verify the reliability of the finite element model. Finally, the influence of corrosion level of steel reinforcement and concrete strength on the normal section bearing capacity of lock-walls were discussed.

Numerical Analysis of Reinforced Concrete Frames Subjected to Fire under Loading

2011 ◽  
Vol 214 ◽  
pp. 637-640
Author(s):  
Gouda M. Ghanem ◽  
Mohamed M. Ebd-Elrazek ◽  
Sayed M. Abd El-Bakey ◽  
Ahmend Ali Hassan ◽  
Esraa Emam Ali
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Reinforced Concrete ◽  
Concrete Strength ◽  
Steel Reinforcement ◽  
Experimental Program ◽  
Concrete Frames ◽  
Element Analysis ◽  
Reinforced Concrete Frames ◽  
Rc Frames

Research over the last decade has shown that composite floor structures can have a significantly greater fire resistance than is suggested by conventional tests on isolated elements, this is largely due to the interaction between the beams and floor slabs and beams-column connections in the fire compartment and the restraint afforded by the surrounding structure. This research was carried out to investigate the effect of fire on the behavior of reinforced concrete frames especially the connection between beam and column, where a special model for a fire furnace was designed in HBRC in order to investigate the aim of the current research. An experimental program consisted of thirteen statically independent two hinged reinforced concrete frames is designed to study the deformational behavior of RC frames subjected to fire under short term loading in terms of deflection and strain distribution, temperatures distribution along the critical cross sections at different limit states with the following variables: fire durations (1,2 and 3 hours), and fire temperatures (300,600 and 800°C) with concrete strength (250 and 600 kg/cm2). Modes of failure, ultimate capacity, deflection and strain of steel reinforcement and concrete at critical sections were examined experimentally and theoretically. The non-linear finite element analysis for reinforced concrete structure is largely dependant on the stress-strain relationships, failure criteria used, simulation of steel reinforcement and interaction between steel and concrete [1]. A model for predicting the behavior of reinforced concrete frames failure was developed based on experimental results obtained from the experimental program carried out by the authors. This model has been incorporated into a new reinforced concrete element for the non-linear analysis program, using ANSYS Ver.10 program. In this paper, a general description of the finite element method, theoretical modeling of concrete and reinforcement are presented. In order to verify the analytical model used in this research using test results of the experimental data of the experimental branch, the finite element analysis were performed then to be able to proposed a guide charts which can be used to predict the moment capacity of joint in beam-column connection in RC frames subjected to fire taking into consideration the different fire durations, fire temperature, and concrete strength.

Analisa Pola Kegagalan Balok Beton Menggunakan GFRP Bar Tanpa Selimut Beton

2020 ◽  
Vol 24 (1) ◽  
pp. 11-16
Author(s):  
Saddam - Husein ◽  
Rudy Djamaluddin ◽  
Rita Irmawaty ◽  
Kusnadi Kusnadi
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beams ◽  
Concrete Cover ◽  
Steel Reinforcement ◽  
Fiber Reinforced Polymer ◽  
Mode Analysis ◽  
Flexural Capacity ◽  
Reinforced Polymer ◽  
Glass Fiber Reinforced ◽  
Gfrp Bar

SADDAM HUSEIN. Analisa Pola Kegagalan Balok Beton Menggunakan GFRP Bar Tanpa Selimut Beton (dibimbing oleh Rudi Djamaluddin dan Rita Irmawaty) Struktur beton bertulang yang menggunakan tulangan baja pada daerah korosif, menjadi rawan terhadap kerusakan atau penurunan kekuatannya akibat korosi.Korosi pada tulangan baja merupakan salah satu faktor penyebab menurunnya kekuatan struktur beton bertulang. Salah satu material yang dikembangkan mengatasi korosi adalah penggunaan material tulangan GFRP (Glass Fiber Reinforced Polymer). Penelitian ini bertujuan untuk menganalisa kapasitas lentur dan pola kegagalan balok beton tanpa selimut dengan menggunakan material tulangan GFRP bar.   Desain penelitian merupakan eksperimental laboratorium dengan rekapitulasi sebanyak 6 sampel yang terdiri dari 2 Balok beton menggunakan tulangan baja dengan selimut beton, 2 balok beton menggunakan tulangan GFRP bar dengan selimut beton, 2 balok beton menggunakan GFRP bar tanpa selimut beton. Metode pengujian dilakukan dengan dengan pengujian lentur statik monotonik dan Analisis data menggunakan uji kondisi retak awal dan kondisi ultimit.   Hasil penelitian ini menunjukkan bahwa kapasitas lentur pada balok dengan tulangan GFRP bar lebih besar dibandingkan dengan balok tulangan baja dan mampu meningkatkan kapasitas lentur balok dalam menahan beban sebesar 39.76 %, pola kegagalan beton yang terjadi pada balok tulangan baja mengalami kegagalan lentur tekan ditandai dengan retakan yang terjadi pada sisi tertekan dan membentuk retakan tegak dengan sumbu netral beton yang tertekan, sedangkan pada balok beton tulangan GFRP tanpa selimut mengalami kegagalan keruntuhan tekan geser dengan kondisi tulangan berdeformasi (bi-linear) dengan retak miring dan secara tiba-tiba menjalar menuju sumbu netral beton yang tertekan sehingga terjadilah keruntuhan secara tiba-tiba.     SADDAM HUSEIN.Failure mode analysis of concrete Beams Using GFRP rebar Without concrete cover (supervised by Rudi Djamaluddin and Rita Irmawaty)   Reinforced concrete that uses rebar steel in corrosive areas, are prone to damage or decreased strength due to corrosion. Corrosion in the steel reinforcement is one of the factors that decreasing strength of reinforced concrete. One of the materials developed to overcome corrosion is the use of GFRP (Glass Fiber Reinforced Polymer) reinforcement material. This study aims to analyze the flexural capacity and failure mode of concrete beams without concrete cover using material GFRP bar as reinforcement.   The research design was an experimental laboratory with a recapitulation of 6 samples consisting of 2 beams using steel reinforcement with concrete cover.2 concrete beams using reinforcement GFRP bar with concrete cover, 2 beams using GFRP bars without concrete cover. The  research method uses the monotonic static flexure and analyzing the data using the initial crack condition and ultimate conditions test.   The results of the research indicate the flexural capacity of the beams with GFRP bar reinforcement is higher than steel reinforcement beams and can increase 39.76% of the flexural capacity of the beams in holding loads , the failure mode analysis occurs in steel reinforcing beam experiences compressive failure. Failure was characterized  by cracks that occur on the depressing side and form an upright crack with the neutral axis of the compressed concrete, whereas in GFRP reinforced concrete beams without concrete cover, failure of shear compression with conditions of deformed reinforcement (bi-linear) with sloping cracks and suddenly spread towards the neutral axis of the compressed concrete so that there was a sudden collapse.

Comparison of Interstorey Drift in General RC Buildings in Pounding and No Pounding Case

2020 ◽  
Vol 2 (1) ◽  
pp. 40-47
Author(s):  
Anand Dev Bhatt
Keyword(s):  
Seismic Analysis ◽  
Linear Time ◽  
Time History ◽  
Case Analysis ◽  
Rc Buildings ◽  
Adjacent Buildings ◽  
Sufficient Distance ◽  
Earthquake Load ◽  
Interstorey Drift ◽  
Lower Height

 Inter-storey drift is an important parameter of structural behavior in seismic analysis of buildings. Pounding effect in building simply means collision between adjacent buildings due to earthquake load caused by out of phase vibration of adjacent buildings. There is variation in inter-storey drift of adjacent buildings during pounding case and no pounding case. The main objective of this research was to compare the inter-storey drift of general adjacent RC buildings in pounding and no pounding case. For this study two adjacent RC buildings having same number of stories have been considered. For pounding case analysis there is no gap in between adjacent buildings and for no pounding case analysis there is sufficient distance between adjacent buildings. The model consists of adjacent buildings having 4 and 4 stories but unequal storey height. Both the buildings have same material & sectional properties. Fast non-linear time history analysis was performed by using El-centro earthquake data as ground motion. Adjacent buildings having different overall height were modelled in SAP 2000 v 15 using gap element for pounding case. Finally, analysis was done and inter-storey drift was compared. It was found that in higher building inter-storey drift is greater in no pounding case than in pounding case but in adjacent lower height building the result was reversed. Additionally, it was found that in general residential RC buildings maximum inter-storey drift occurs in 2nd floor.

Critical shear crack theory-based punching shear model for FRP-reinforced concrete slabs

2020 ◽  
pp. 136943322097814
Author(s):  
Xing-lang Fan ◽  
Sheng-jie Gu ◽  
Xi Wu ◽  
Jia-fei Jiang
Keyword(s):  
Shear Strength ◽  
Reinforced Concrete ◽  
Shear Crack ◽  
Concrete Strength ◽  
Weight Ratio ◽  
Punching Shear ◽  
Concrete Slabs ◽  
Crack Theory ◽  
Reinforced Concrete Slabs ◽  
Rc Slabs

Owing to their high strength-to-weight ratio, superior corrosion resistance, and convenience in manufacture, fiber-reinforced polymer (FRP) bars can be used as a good alternative to steel bars to solve the durability issue in reinforced concrete (RC) structures, especially for seawater sea-sand concrete. In this paper, a theoretical model for predicting the punching shear strength of FRP-RC slabs is developed. In this model, the punching shear strength is determined by the intersection of capacity and demanding curve of FRP-RC slabs. The capacity curve is employed based on critical shear crack theory, while the demand curve is derived with the help of a simplified tri-linear moment-curvature relationship. After the validity of the proposed model is verified with experimental data collected from the literature, the effects of concrete strength, loading area, FRP reinforcement ratio, and effective depth of concrete slabs are evaluated quantitatively.

scholarly journals Bond Behaviour of Near-Surface Mounted Strips in RC Beams—Experimental Investigation and Numerical Simulations

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4362
Author(s):  
Renata Kotynia ◽  
Hussien Abdel Baky ◽  
Kenneth W. Neale
Keyword(s):  
Concrete Strength ◽  
Element Model ◽  
Steel Reinforcement ◽  
Reinforcement Ratio ◽  
Experimental Program ◽  
Fe Model ◽  
Bond Behaviour ◽  
Near Surface ◽  
Cfrp Laminates ◽  
Near Surface Mounted

This paper presents an investigation of the bond mechanism between carbon fibre reinforced polymer (CFRP) laminates, concrete and steel in the near-surface mounted (NSM) CFRP-strengthened reinforced concrete (RC) beam-bond tests. The experimental program consisting of thirty modified concrete beams flexurally strengthened with NSM CFRP strips was published in. The effects of five parameters and their interactions on the ultimate load carrying capacities and the associated bond mechanisms of the beams are investigated in this paper with consideration of the following investigated parameters: beam span, beam depth, longitudinal tensile steel reinforcement ratio, the bond length of the CFRP strips and compressive concrete strength. The longitudinal steel reinforcement was cut at the beam mid-span in four beams to investigate a better assessment of the influence of the steel reinforcement ratio on the bond behaviour of CFRP to concrete bond behaviour. The numerical analysis implemented in this paper is based on a nonlinear micromechanical finite element model (FEM) that was used for investigation of the flexural behaviour of NSM CFRP-strengthened members. The 3D model based on advanced CFRP to concrete bond responses was introduced to modelling of tested specimens. The FEM procedure presents the orthotropic behaviour of the CFRP strips and the bond response between the CFRP and concrete. Comparison of the experimental and numerical results revealed an excellent agreement that confirms the suitability of the proposed FE model.

Analysis of Reinforced Concrete Culvert considering Concrete Creep and Shrinkage

1996 ◽  
Vol 1541 (1) ◽  
pp. 120-126
Author(s):  
Charles J. Oswald
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Cross Sections ◽  
Soil Structure ◽  
Silty Clay ◽  
Soil Pressure ◽  
Concrete Creep ◽  
Long Span ◽  
Creep And Shrinkage ◽  
Good Agreement

Measurements made on a long span reinforced concrete arch culvert under 7.3 m (24 ft) of silty clay backfill were compared with results from finite-element analyses of the soil-structure system using the CANDE finite-element code. The culvert strains and deflections and the soil pressure on the culvert were measured during construction and during the following 2.5 years at three instrumented cross sections. The CANDE program was modified to account for the effects of concrete creep and shrinkage strains after it was noted that the measured postconstruction culvert deflection and strains increased significantly whereas the measured soil pressure on the culvert remained relatively constant. Good agreement was generally obtained between measured and calculated values of the culvert strain and deflection and the soil pressure during the entire monitoring period after the code was modified.

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