Multi-Type Finite Elements Hybrid Model for Simulating Global Behavior of Reinforced Concrete Frames in Fires

2013 ◽  
Vol 353-356 ◽  
pp. 2357-2361
Author(s):  
Yong Jun Liu ◽  
Yang Yang Liu ◽  
Ran Bi ◽  
Jing Hai Zhou
Keyword(s):  
Reinforced Concrete ◽  
Finite Elements ◽  
Hybrid Model ◽  
Large Scale ◽  
Research Work ◽  
Concrete Structures ◽  
Concrete Frames ◽  
Reinforced Concrete Frame ◽  
Element Analysis ◽  
Reinforced Concrete Frames

In general, reinforced concrete frames have excellent fire resistance properties, but more and more concrete buildings collapsed in fires. The majority of past research work on the response of concrete building to fire has looked at the effects of fire upon individual structural members, and most commonly when subjected to heating from standard fire tests. At present, the fire behaviors of whole reinforced concrete frame are not adequately understood. There is a great need for development of models which consider the effects of fire on the whole structure under more realistic heating regimes. There is also a fundamental requirement for further large-scale testing of concrete structures, to observe the behavior of whole concrete structures in real fires and also for validation of advanced computer analysis tools. Accuracy and efficiency are two major concerns in finite element analysis of structural response of concrete frames in fires. In this paper, a multi-type finite elements hybrid model for simulating structural behavior of whole reinforced concrete frames in real fire is suggested.

Experimental Investigation and Crack Resistance Analysis on Large Scale Prestressed Steel Reinforced Concrete Frame

2011 ◽  
Vol 255-260 ◽  
pp. 524-528
Author(s):  
Xue Yu Xiong ◽  
Feng Gao ◽  
Yang Li
Keyword(s):  
Reinforced Concrete ◽  
Large Scale ◽  
Concrete Structures ◽  
Engineering Application ◽  
Concrete Frames ◽  
Reinforced Concrete Frame ◽  
Static Test ◽  
Concrete Frame ◽  
Concrete Members ◽  
Axial Forces

Based on the static test of large-scaled prestressed steel concrete frames, the behavior of crack were tested and investigated. In this paper, according to theory of reinforced concrete members, Code for design of concrete structures(GB 50010-2002)and code ACI 318—05, the formulas of cracking moment considering secondary axial forces were deduced and verified by test results. Conclusion can be drawn as follow: the calculation errors of formulas derive from theory of reinforced concrete members is small, generally less than 6%; the errors of formulas referring to Code for design of concrete structures(GB 50010-2002)is about 10%, which is satisfy the needs of engineering and simply to be calculated; Cracking moment calculated by formulas referring to code ACI 318—05 is less than test result, it is unsafe for engineering application.

scholarly journals Investigation of Diagonal Strut Actions in Masonry-Infilled Reinforced Concrete Frames

2021 ◽  
Vol 15 (1) ◽  
Author(s):  
Seung-Jae Lee ◽  
Tae-Sung Eom ◽  
Eunjong Yu
Keyword(s):  
Reinforced Concrete ◽  
Failure Mode ◽  
Yield Criterion ◽  
Friction Angle ◽  
Concrete Frames ◽  
Element Analysis ◽  
Reinforced Concrete Frames ◽  
Infilled Frames ◽  
Masonry Infills ◽  
Push Down

AbstractThis study analytically investigated the behavior of reinforced concrete frames with masonry infills. For the analysis, VecTor2, a nonlinear finite element analysis program that implements the Modified Compression Field Theory and Disturbed Stress Field Model, was used. To account for the slip behavior at the mortar joints in the masonry element, the hyperbolic Mohr–Coulomb yield criterion, defined as a function of cohesion and friction angle, was used. The analysis results showed that the lateral resistance and failure mode of the infilled frames were significantly affected by the thickness of the masonry infill, cohesion on the mortar joint–brick interface, and poor mortar filling (or gap) on the masonry boundary under the beam. Diagonal strut actions developed along two or three load paths on the mortar infill, including the backstay actions near the tension column and push-down actions near the compression columns. Such backstay and push-down actions increased the axial and shear forces of columns, and ultimately affect the strength, ductility, and failure mode of the infilled frames.

scholarly journals Mechanical behavior of the reinforced concrete frame with masonry filling Comportement mécanique des portiques en béton armé avec remplissage en maçonnerie

2018 ◽  
Vol 149 ◽  
pp. 02062
Author(s):  
Jalal Kettar ◽  
Khadija Baba ◽  
Abderrahman Nounah ◽  
Lahcen Bahi
Keyword(s):  
Reinforced Concrete ◽  
Structural Characteristics ◽  
Quality Parameters ◽  
The Other ◽  
Practical Calculation ◽  
Filling Material ◽  
Reinforced Concrete Structure ◽  
Concrete Frames ◽  
Reinforced Concrete Frame ◽  
Reinforced Concrete Frames

Masonry is often used in the most of reinforced concrete structure constructions as a filling material that is important on structural characteristics. Structural contribution in the calculations was neglected or misunderstood, mainly due to the lack of a practical calculation methods and an appropriate regulatory tool. The analysis of frames filled with masonry is very complex. This complexity is linked from one part to the difference in the nature of elements and its behavior that make up the masonry itself (brick and mortar) and their interaction, and on the other part, for the large dispersion that characterizes the bricks as well as the execution's quality parameters which make it difficult to define reliable criteria for the masonry. The objective of this work is to experimentally highlight the influence of the hollow brick masonry filler, commonly used in Morocco, on reinforced concrete frames subject to lateral stresses, to deepen understanding the seismic behavior of the masonry structures by evaluating the structural performance of a specimen wall. These experimental results will be compared to those found by modeling prototypes, using SAP 2000 software, based on various approaches and models as well as other results deduced from the other researchers. The experimental study was carried out according to standard NF EN 1052-3 on two reinforced concrete frames, of dimensions (2m X 1.6m), the one with the masonry filling, and the other without filling in order to determine the initial characteristic resistance to the shearing of the masonry walls. The obtained results showed that a filling has a beneficial effect on rigidity which can be doubled compared to an empty frame. in the same way the lateral resistance. But this effect is much contrasted; it depends a lot on the characteristics essentially of the materials (bricks and concrete). This is the main reason, which justifies the divergence of the results deduced from the nine models that we used.

Analytical investigation of reinforced concrete frames under middle column removal scenario

2017 ◽  
Vol 21 (9) ◽  
pp. 1388-1401 ◽  
Author(s):  
Foad Mohajeri Nav ◽  
Nima Usefi ◽  
Reza Abbasnia
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Theoretical Model ◽  
Comprehensive Evaluation ◽  
Progressive Collapse ◽  
Concrete Frames ◽  
Reinforced Concrete Frame ◽  
Reinforced Concrete Frames ◽  
Proposed Model ◽  
Column Removal

A simplified theoretical model is developed in the present study in order to predict the general behavior and resistance of reinforced concrete frames under column removal scenarios. The proposed model defines the load–deflection response of the middle joint above the removed column based on a four-stage procedure: classical beam mechanism stage, arching stage, transient stage, and catenary stage. A comprehensive evaluation study using two validation approaches is performed in order to investigate the reliability of the introduced model. For validation of theoretical model, the results of a comprehensive finite element method and experimental data were utilized and the results were compared with the theoretical model. The results demonstrated that the proposed theoretical procedure can establish a reliable foundation for progressive collapse assessment of reinforced concrete frame structures. The proposed model can also predict behavior of symmetrical frames, and this was validated by good agreement between finite element results and the results of the proposed numerical model.

Behavior of Framed Shearwalls Made of Corrugated Steel under Lateral Load Reversals

2000 ◽  
Vol 3 (3) ◽  
pp. 255-262 ◽  
Author(s):  
Y.L. Mo ◽  
S.F. Perng
Keyword(s):  
Reinforced Concrete ◽  
Seismic Behavior ◽  
Concrete Frames ◽  
Reinforced Concrete Frame ◽  
Reinforced Concrete Frames ◽  
Fiber Reinforced Plastic ◽  
Concrete Frame ◽  
Plastic Composites ◽  
Reinforced Plastic ◽  
Critical Regions

Reinforced concrete buildings with shearwalls are very efficient to resist earthquake disturbances. In general, reinforced concrete frames are governed by flexure and low-rise shearwalls are governed by shear. If a structure includes both frames and shearwalls, it is generally governed by shearwalls. However, the ductility of ordinary reinforced concrete framed shearwalls is very limited. The experiments on framed shearwalls made of corrugated steel was recently reported. It was found that the ductility of framed shearwalls can be greatly improved if the thickness of the corrugated steel wall is appropriate to the surrounding reinforced concrete frame. If the thickness of the corrugated steel wall is too large when compared to the surrounding frame, the ductility will be reduced. It is shown in this paper that the fiber-reinforced plastic composites can be used to strengthen the critical regions of the reinforced concrete frames, so that the seismic behavior (including ductility and energy dissipation capability) is greatly improved.

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.

scholarly journals Strengthening of vulnerable RC moment resisting frames using direct internal connection of X-steel bracing

2021 ◽  
Author(s):  
Siavash Sadeghinezhad ◽  
Ali Kheyroddin ◽  
Alireza Mortezaei
Keyword(s):  
Reinforced Concrete ◽  
Large Scale ◽  
Concrete Frames ◽  
Reinforced Concrete Frame ◽  
Gusset Plate ◽  
Concrete Frame ◽  
Soft Story ◽  
Internal Connection ◽  
Panel Zone ◽  
Moment Resisting

Non-ductile reinforced concrete frames are commonly found in older buildings in many parts of the world. These structures designed for gravity loads, have limited lateral strength and ductility, are prone to excessive one-way lateral movement and soft-story mechanism. This paper focuses on the retrofit of an existing reinforced concrete frame, using steel X-braces by direct internal connection method. The main purpose is the analytical study of general behavior and response of large scale vulnerable frames. An experimental study was used to validate the numerical modeling performed in ABAQUS. Next the base samples were retrofitted with X-braces and four proposed direct internal connection methods. Furthermore, in a separate parametric studies, the effect of frame type, bracing cross-section dimensions and gusset plate shape were investigated. The results indicated that the stiffness, bearing capacity and absorbed energy of the reinforced concrete frame by using steel X-braces increases up to 4, 2.3 and 1.5 times, respectively. Moreover, bracing acts like the first defense system against lateral loads, such as structural fuse with its yield, increases the amount of energy dissipation. It also removes the plastic hinges by reducing the ultimate displacement and stress of lateral load in the panel zone.

scholarly journals On the use of parameter γ z in fire situation

2019 ◽  
Vol 12 (6) ◽  
pp. 1327-1344
Author(s):  
E. A. K. NACCACHE ◽  
I. PIERIN ◽  
V. P. SILVA
Keyword(s):  
Reinforced Concrete ◽  
Room Temperature ◽  
Concrete Structures ◽  
Concrete Frames ◽  
Geometric Imperfections ◽  
Reinforced Concrete Frames ◽  
Load Combination ◽  
The Subject ◽  
In Fire ◽  
Horizontal Action

Abstract Herein will be presented a study on the use of parameter γz for reinforced concrete frames in fire situation. Currently, there are no results of similar research for concrete structures, since the subject has not received the adequate attention. In fire situation, many of the horizontal actions are no longer considered in exceptional load combination, leaving only the horizontal action due to the global geometric imperfections. Once the equivalent horizontal forces to these imperfections are obtained, the parameter is applied. One of the conclusions was that the parameter γz is not adequate, in particularly for high buildings, indicating that more research is necessary. Even so, using γz for room temperature, we conclude that fires that affect lower floors are more damaging to the building and more floors under fire also lead to worse results.

scholarly journals Assessment of Seismic Capacity for Reinforced Concrete Frames with Perforated Unreinforced Brick Masonry Infill Wall

2020 ◽  
Vol 6 (12) ◽  
pp. 2397-2415
Author(s):  
Muhammad Umar ◽  
Syed Azmat Ali Shah ◽  
Khan Shahzada ◽  
Muhammad Tayyab Naqash ◽  
Wajid Ali
Keyword(s):  
Reinforced Concrete ◽  
Experimental Testing ◽  
Research Work ◽  
Rc Frame ◽  
Concrete Frames ◽  
Infill Wall ◽  
Reinforced Concrete Frames ◽  
Infill Walls ◽  
Rc Frames ◽  
Infilled Rc Frames

Infill walls increase the strength and stiffness of the reinforced concrete frames, but they usually are not considering in design. However, when the infills are considered in the design, the opening for doors/windows necessitates investigation as well. This research work aims to investigate the effect of perforations (openings) in the infill walls on the performance of infilled RC frames, in other words, this research investigates the number of infill walls in infilled RC frames. Based on the current construction practices in Pakistan, two full scales perforated infilled RC frames were constructed in the laboratory. One infilled RC frame has an eccentric door and window (specimen-1) while the other has only window at its centre (specimen-2). Both the specimens were tested against reverse cyclic loading (quasi-static test). From the experimental testing, it was found that infilled RC frame having less amount of opening in infill wall has more resistance to lateral loads, have more stiffness and dissipated higher energy as compared to infilled RC frame having a significant size of the opening in infill wall. Similarly, displacement ductility (µD) and Response modification factor (R) also depend on the quantity of opening in infill wall in infilled RC frame. Doi: 10.28991/cej-2020-03091625 Full Text: PDF

scholarly journals An Investigation on Sheeting Acting as a Diaphragm on a Reinforced Precast Concrete Frame

2020 ◽  
Author(s):  
Sergiu-Gheorghe Țere ◽  
Bogdan Hegheș ◽  
Horea Constantinescu
Keyword(s):  
Reinforced Concrete ◽  
Experimental Test ◽  
Precast Concrete ◽  
Steel Structures ◽  
Concrete Frames ◽  
Reinforced Concrete Frame ◽  
Reinforced Concrete Frames ◽  
Concrete Frame ◽  
Steel Sheets ◽  
Starting Point

It is well-known that for single-storey steel structures, the framework is greatly strengthened and stiffened following the attachment of the roof, floors and walls. The panels in the roofing, flooring and side cladding are also known as “shear diaphragms” by virtue of their resistance to being deformed into parallelograms. This has been verified by on-site practical experience of many structures and design provisions are available for structural engineers. Despite the fact that for single-storey structures, the corrugated steel sheets are the standard elements in constructing the envelopes, in what concerns the reinforced concrete frames there are no guidelines nor recommendations on how to consider the diaphragm effect in structural analysis. In order to better understand the interaction between the corrugated steel sheets and the reinforced concrete frame, a real precast reinforced concrete frame structure was built for experimental testing. The aim of the experimental test is to study the diaphragm effect for reinforced concrete structures and based on the results to identify the discrepancies identified compared to steel structures. The investigation attempts to provide a starting point for future research on the stressed skin design acting on reinforced concrete frames. At the end of the article conclusions are drawn based on the experience obtained during the experimental test.

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