scholarly journals NONLINEAR MULTILEVEL ANALYSIS OF REINFORCED CONCRETE FRAMES

2016 ◽  
Vol 7 (4) ◽  
pp. 168-176 ◽  
Author(s):  
Pui Lam Ng ◽  
Jeffery Yuet Kee Lam ◽  
Albert Kwok Hung Kwan
Keyword(s):  
Reinforced Concrete ◽  
Multilevel Analysis ◽  
Crack Opening ◽  
Full Range ◽  
Analysis Method ◽  
Concrete Frames ◽  
Range Analysis ◽  
Strength Deterioration ◽  
Rc Frames ◽  
Frame Member

Full range analysis of reinforced concrete (RC) members covering the post-crack and post-peak regimes is important for obtaining the deformation response and failure mode of structural members. When a RC member is subject to an increasing external load, the critical sections would exhibit cracking and/or softening. Due to stress relief effect in the proximity of crack opening and plastic hinging, unloading may occur at the adjacent regions. The variable stress states of discrete sections would lead to sectional variation of stiffness, which could not be accounted for by conventional structural analysis methods. In this paper, a nonlinear multilevel analysis method for RC frames whereby the frame members are divided into sub-elements and sectional analysis is utilised to evaluate stiffness degradation and strength deterioration is developed. At sectional level, the secant stiffness is determined from moment-curvature relation, where the curvature is evaluated based on both transverse displacements and section rotations of the frame member. Unloading and reloading behaviour of concrete and reinforcing steel is simulated. In implementing the multilevel analysis, secant iteration is performed in each step of displacement increment to obtain the convergent solution satisfying equilibrium. Numerical example of RC frame is presented to demonstrate the applicability and accuracy of the proposed nonlinear multilevel analysis method.

scholarly journals Damage Source Identification of Reinforced Concrete Structure Using Acoustic Emission Technique

2013 ◽  
Vol 2013 ◽  
pp. 1-5
Author(s):  
Alireza Panjsetooni ◽  
Norazura Muhamad Bunnori ◽  
Amir Hossein Vakili
Keyword(s):  
Acoustic Emission ◽  
Reinforced Concrete ◽  
Nondestructive Evaluation ◽  
Analysis Method ◽  
Reinforced Concrete Structure ◽  
Acoustic Emission Technique ◽  
Rc Structures ◽  
Rc Frames ◽  
Damage Monitoring ◽  
Investigation Process

Acoustic emission (AE) technique is one of the nondestructive evaluation (NDE) techniques that have been considered as the prime candidate for structural health and damage monitoring in loaded structures. This technique was employed for investigation process of damage in reinforced concrete (RC) frame specimens. A number of reinforced concrete RC frames were tested under loading cycle and were simultaneously monitored using AE. The AE test data were analyzed using the AE source location analysis method. The results showed that AE technique is suitable to identify the sources location of damage in RC structures.

Behavior Study of High Impact Resistant Reinforced Concrete Frames Using Crack Conduction Method

2006 ◽  
Author(s):  
Navid Heidarzadeh ◽  
S. Mohammad Razavi ◽  
Nima Shamsaei
Keyword(s):  
Reinforced Concrete ◽  
Impact Loading ◽  
Failure Modes ◽  
Side Surface ◽  
High Impact ◽  
Structural Behavior ◽  
Concrete Frames ◽  
Rc Frames ◽  
Behavior Study ◽  
Falling Weight

In this study, the influence of crack conduction method on behavior of reinforced concrete (RC) frame under iterative high impact loading were experimented. To investigate the structural behavior through large deformations and progressive damage and to identify the failure modes, the falling weight and falling height were set more than the structural strength in elastic state. A comprehensive scheme which indicated influence of location of initial cracks on behavior and failure mode of structure was developed. Falling weight impact test was conducted on twenty-one laboratory scaled RC frames which were categorized in four series regard to considered scheme. Concrete volume and compressive strength, number of longitudinal and transverse rebar were constant factors in all specimens. Deformed shape and crack patterns, developed on the side surface of the RC frames, were sketched and total deflections vs. cumulative input energy of the RC girder were plotted. The results revealed the influence of crack conduction on improving the structural behavior and extending the endurance of RC frames against iterative high impact loading.

Calculation Methods of CFRP Tendons Stress in Two-Span Prestressed Continuous Beams

2013 ◽  
Vol 859 ◽  
pp. 60-63
Author(s):  
Chong Xi Bai ◽  
Xin Yan Shao ◽  
Qiu Ping Wang
Keyword(s):  
Simulation Analysis ◽  
Full Range ◽  
Fiber Reinforced Polymer ◽  
Analysis Method ◽  
Stress Increment ◽  
Range Analysis ◽  
Reinforced Polymer ◽  
Continuous Beams ◽  
Unbonded Tendons ◽  
Deformation Compatibility

Crack width, deflection and load bearing capacity of two-span concrete continuous beams partially prestressed with unbonded carbon fiber reinforced polymer (CFRP) tendons can be calculated accurately, the first premise is to calculate reasonably the stress increment of CFRP tendons. However, the law of stress increment of unbonded tendons is unclear. Moment-curvature analysis method and deformation compatibility condition were used to compile nonlinear full-range analysis programs of this kind of continuous beam. The comparison between simulated results and tested results of stress in CFRP tendons indicates that the simulation analysis programs are reliable.

Ductility Reduction Factors for Masonry-Infilled Reinforced Concrete Frames

2015 ◽  
Vol 31 (1) ◽  
pp. 339-365 ◽  
Author(s):  
Manish Kumar ◽  
Durgesh C. Rai ◽  
Sudhir K. Jain
Keyword(s):  
Reinforced Concrete ◽  
Traditional Approach ◽  
Statistical Tests ◽  
Experimental Studies ◽  
Reduction Factor ◽  
Model Parameters ◽  
Deformation Model ◽  
Concrete Frames ◽  
Ductility Demand ◽  
Rc Frames

Masonry-infilled reinforced concrete (RC) frames are popular structural systems; however, there is much uncertainty in their response under seismic loads. Using the data from past experimental studies, a simple force-deformation model with three control points was developed. The effect of the model parameters on the ductility reduction factor (DRF) and ductility demand (DD) was examined. Statistical tests indicated that the ratio of residual strength to peak strength was the most significant parameter. The traditional approach to determining DRF ordinates through iteration for an assumed value of ductility may result in inappropriate DRF values because of the nonmonotonic relationship between DRF and DD. Constant ductility charts were developed to appropriately account for nonmonotonicity. It was found that the allowable DRF may be much higher if relatively weaker infill compared to the strength of the frame is used, which underscores the need for modifying code provisions because they allow relatively strong infill.

scholarly journals Effect of Different Bracing Systems in Reinforced Concrete Frames under Cyclic Loading

2020 ◽  
Vol 9 (7) ◽  
pp. 704-708
Keyword(s):  
Reinforced Concrete ◽  
Cyclic Loading ◽  
Structural Parameters ◽  
Rc Frame ◽  
Concrete Frames ◽  
Element Analysis ◽  
Framed Structures ◽  
Rc Frames ◽  
Seismic Force ◽  
Rc Framed Structures

Reinforced concrete (RC) framed structures are widely used as load transferring system in residential and commercial buildings. Even though the RC frames are designed for gravitational and seismic forces, but they are week under severe seismic events. The main disadvantage of the framed structures is inefficient bracing systems designed in it. This investigation is conducted mainly to study the effective bracing system in the RC framed structure to transfer the seismic force. This research aims to study the seismic performance of RC frames influenced by the various types of cross bracings under cyclic loading. The finite element analysis software package ABAQUS is used to investigate the braced RC frames analytically. The research scheme consists of three RC frames; the bare frame, the bare frame with single X-bracing (X frame), double X bracing (D-X frame) along the height. The structural parameters include, load-displacement hysteresis envelope, stiffness degradation and energy absorption were studied to analyze the performance of bracings. The results showed that the X frame and D-X frame noticeably increased the lateral strength, stiffness and energy dissipation properties compared to the bare RC frame. The results also indicated that the addition of X bracing along the height significantly enhanced the structural parameters of the RC frame.

scholarly journals Strength and ductility in reinforced concrete frames designed with Mexican codes

1990 ◽  
Vol 23 (3) ◽  
pp. 184-197 ◽  
Author(s):  
M. Rodriguez
Keyword(s):  
Reinforced Concrete ◽  
Structural Damage ◽  
Analytical Models ◽  
Reinforcing Steel ◽  
Concrete Frames ◽  
Approximate Methods ◽  
Reinforced Concrete Frames ◽  
Rc Frames ◽  
Mexico Earthquake ◽  
Strength And Ductility

The strength and ductility capacities of several structural sections of members in typical reinforced concrete frames designed with Mexican Codes are calculated using analytical models for confined concrete and reinforcing steel. These ductility capacities are associated with global displacement ductilities in the RC frames using approximate methods of analysis described in this paper. Results obtained in this investigation are correlated with typical pattern of structural damage in RC frames observed during the 1985 Mexico Earthquake. Some aspects of the seismic performance of fully ductile frames designed according to the 1987 Mexico City Building Code are also discussed, as well as the effect of some mechanical properties of reinforcing steel on the strength and ductility of RC frames.

Full-Range Analysis of Concrete Frames

1973 ◽  
Vol 99 (8) ◽  
pp. 1761-1783
Author(s):  
Angel L. Lazaro ◽  
Rowland Richards
Keyword(s):  
Full Range ◽  
Concrete Frames ◽  
Range Analysis
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