scholarly journals Advanced Composite Retrofit of RC Columns and Frames with Prior Damages—Pseudodynamic Finite Element Analyses and Design Approaches

Fibers ◽  
2021 ◽  
Vol 9 (9) ◽  
pp. 56
Author(s):  
Theodoros Rousakis ◽  
Evgenia Anagnostou ◽  
Theodora Fanaradelli
Keyword(s):  
Finite Element ◽  
Brick Wall ◽  
Rc Frame ◽  
Base Shear ◽  
Infill Wall ◽  
Rc Columns ◽  
Premature Failure ◽  
Displacement Ductility ◽  
Lap Splices ◽  
Rc Frames

This study develops three-dimensional (3D) finite element (FE) models of composite retrofits in deficient reinforced concrete (RC) columns and frames. The aim is to investigate critical cases of RC columns with inadequate lap splices of bars or corroded steel reinforcements and the beneficial effects of external FRP jacketing to avoid their premature failure and structural collapse. Similarly, the RC-frame FE models explore the effects of an innovative intervention that includes an orthoblock brick infill wall and an advanced seismic joint made of highly deformable polymer at the boundary interface with the RC frame. The experimental validation of the technique in RC frames is presented in earlier published papers by the authors (as well as for a four-column structure), revealing the potential to extend the contribution of the infills at high displacement ductility levels of the frames, while exhibiting limited infill damages. The analytical results of the advanced FE models of RC columns and frames compare well with the available experimental results. Therefore, this study’s research extends to critical cases of FE models of RC frames with inadequate lap splices or corroded steel reinforcements, without or with brick wall infills with seismic joints. The advanced pseudodynamic analyses reveal that for different reinforcement detailing of RC columns, the effects of inadequate lap-spliced bars may be more detrimental in isolated RC columns than in RC frames. It seems that in RC frames, additional critical regions without lap splices are engaged and redistribution of damage is observed. The detrimental effects of corroded steel bars are somewhat greater in bare RC frames than in isolated RC columns, as all reinforcements in the frame are considered corroded. Further, all critical cases of RC frames with prior damages at risk of collapse may receive the innovative composite retrofit and achieve higher base shear load than the original RC frame without corroded or lap-spliced bars, at comparable top displacement ductility. Finally, the FE analyses are utilized to propose modified design equations for the shear strength and chord rotation in cases of failure of columns with deficiencies or prior damages in RC structures.

Cyclic Performance of Two-Story Ductile RC Frames With Infill Walls

2005 ◽  
Author(s):  
Yung-Hsin Yeh ◽  
Wen-I Liao
Keyword(s):  
Model Building ◽  
General Purpose ◽  
Rc Frame ◽  
Building Structures ◽  
Base Shear ◽  
Concrete Frames ◽  
Infill Wall ◽  
Infill Walls ◽  
Rc Frames ◽  
Short Beam

This paper presents the results of the experimental and analytical investigations conducted on four 0.8 scale 2-story one bay ductile reinforced concrete frames with infill nonstructural walls subjected to cyclically increasing loads. The material properties and the member sizes of beams and columns in the four RC frame specimens are identical, but with different types of infill nonstructural wall. These four frames are the pure frame, frame with short column, frame with short beam and frame with wing walls. The four RC frame specimens were designed and constructed according to the general prototype building structures in Taiwan. Test results indicate that the ductility behavior of the frames with infill wall is similar to those of the pure frame. The ultimate base shear strength of the frames with infill walls is higher than those of the pure frame. Analytical results show that the proposed simplified multi-linear beam-column element implemented in a general purpose structural analysis program can accurately simulate the cyclic responses of the RC frame specimen incorporating the elastic flexural stiffness computations suggested by the model building codes.

Seismic performance of RC frames strengthened by RC infill walls

2021 ◽  
pp. 136943322199772
Author(s):  
Shao-Ge Cheng ◽  
Yi-Xiu Zhu ◽  
Wei-Ping Zhang
Keyword(s):  
Masonry Walls ◽  
Rc Frame ◽  
Seismic Line ◽  
Shake Table Tests ◽  
Infill Walls ◽  
Displacement Ductility ◽  
Rc Frames ◽  
Story Drift ◽  
Comparison Of The Results ◽  
Bending Failure

This study presents the shake-table tests of a 1/5-scaled RC frame retrofitted with RC infill walls. The intensity of input ground motions increased gradually to comprehensively evaluate the structural seismic behavior. We performed a comparison of the results from the RC frame with masonry walls and that with RC walls. The results showed that the presence of RC infills effectively improved the lateral structural stiffness and loading capacity of the frames and reduced their damage and story drift. RC walls acted as the first seismic line of defense, and their failure was dominated by bending failure and concentrated on the low stories. The displacement ductility of the structure decreased with increasing stiffness of the introducing infills.

Comparative study on seismic performance of specially shaped RC columns with that of rectangular columns in high-rise structures

2019 ◽  
Vol 11 (2) ◽  
pp. 202-215
Author(s):  
Shanmukha Shetty ◽  
Subrahmanya R.M. ◽  
Sushanth Bhandary ◽  
Thushar Shetty
Keyword(s):  
Pushover Analysis ◽  
Geometrical Shape ◽  
Structural Elements ◽  
Base Shear ◽  
Percent Reduction ◽  
Rc Columns ◽  
Content Type ◽  
High Rise ◽  
Rc Frames ◽  
Rectangular Columns

Purpose Columns are structural elements that are predominantly subjected to compressive forces and moments that are to be transferred from the super-structure to the sub-structure. The geometrical shape of a column is a significant factor to be considered. The paper aims to discuss this issue. Design/methodology/approach Pushover analysis is carried out, to study the behavior of RC frames with rectangular and specially shaped columns for the same building layout. Findings Reduction of 27.3 percent in base shear, 67.4 percent in spectral displacement, 66.5 percent reduction in storey displacement, 70.22 percent in storey drift and 0.315 percent reduction in storey shear is observed. Practical implications Special shaped RC columns can effectively enhance the structural behavior of high rise structures under seismic excitation in comparison to those with regular shaped RC columns. Originality/value Applications of special shaped columns in structures have showed a great deal of reduction in displacement and shear forces developed due to seismic activity, for the same area of concrete and steel as in rectangular columns.

scholarly journals Seismic Behavior of Nonductile RC Frame Slotted with Corrugated Steel Plate Shear Walls

2021 ◽  
Vol 2021 ◽  
pp. 1-23
Author(s):  
Ningning Feng ◽  
Changsheng Wu
Keyword(s):  
Finite Element ◽  
Boundary Conditions ◽  
Seismic Behavior ◽  
Steel Plate ◽  
Concrete Strength ◽  
Shear Walls ◽  
Slit Width ◽  
Rc Frame ◽  
Steel Plate Shear Walls ◽  
Rc Frames

Two specimens of nonductile reinforced concrete (RC) frame (ND-1) and nonductile RC frame retrofitted by corrugated steel plate shear walls slotted with columns (ND-2) are established by finite element. These specimens have same dimensions and steel skeletons. Finite element models had been verified by the existing experimental results. The hysteresis curves, skeleton curves, ductility, and stiffness curves of Specimen ND-1 and Specimen ND-2 are compared. The results show that the reinforcement effect is significant. Twenty-four models are built to study the seismic behavior on different influence parameters. The parameters are slit width, thickness of corrugated steel plate shear walls, concrete strength of nonductile RC frame, and boundary conditions of corrugated steel plate shear walls at slotted parts. The results indicate that the strength is declined with the increase of slit width. With the increase of thickness and concrete strength, the strength and stiffness are enhanced. The strength is larger with the boundary than without. Slit width and thickness have an important impact on the stiffness. Concrete strength and boundary conditions have little impact on stiffness. The strengthened nonductile RC frames have enough ductility.

Research on the Connection Modes and Numerical Simulation Methods of RC Frame and Infill Wall

2013 ◽  
Vol 671-674 ◽  
pp. 549-554
Author(s):  
Huan Jin
Keyword(s):  
Finite Element ◽  
Nonlinear Behavior ◽  
Element Model ◽  
Interface Element ◽  
Infill Wall ◽  
Rc Frames ◽  
Highly Nonlinear ◽  
Rigid Connection ◽  
Infilled Rc Frames ◽  
Masonry Infilled Rc Frames

In the evaluation of the seismic performance of masonry-infilled RC frames, the main difficulty is determining the type of interaction between the infill and the frame, which has a major impact on the structural behavior and load-resisting mechanism. This paper addresses the connection modes of the RC frames and masonry panels in regulations in China. The method of flexible connection suggested in standard has not been widely used in actual engineering, and rigid connection was adopted in universal. The finite element model with interface element is advisable for simulating the interaction of the frames and panels, and the accuracy of the nonlinear finite-element models has been evaluated with experimental data. The comparison of the numerical and experimental results indicates that the models can successfully capture the highly nonlinear behavior of the physical specimens and accurately predict their strength and failure mechanisms.

Experimental Study on Seismic Performance of CFRP Strengthened RC Frames Damaged by Earthquake

2013 ◽  
Vol 724-725 ◽  
pp. 1749-1753
Author(s):  
Qiu Mei Gao ◽  
Lai Wang ◽  
Ying Zhang
Keyword(s):  
Seismic Performance ◽  
Test Method ◽  
Hysteresis Curve ◽  
Rc Frame ◽  
Loading Test ◽  
Skeleton Curve ◽  
Static Test ◽  
Displacement Ductility ◽  
Rc Frames ◽  
Industry Standards

In this paper, we carried out low cyclic loading test over CFRP strengthened seismic-damaged RC frame named KJ-2 with the quasi-static test method, and compared the seismic performance with the same sections and materials RC frame named KJ-1 which was unstrengthened. We study the seismic performance such as hysteresis curve, skeleton curve, stiffness degradation, bearing capacity degeneration, displacement ductility, and energy dissipation capacity of the reinforced RC frame. On this basis, we analyzed the results of this test in order to obtain some guiding opinions for asymmetric span RC frames that strengthened by CFRP, and provide main preference basis or future national or industry standards.

Cracking Simulative Analysis of Reinforced Concrete Columns with ANSYS Software

2014 ◽  
Vol 578-579 ◽  
pp. 946-949
Author(s):  
Guo Jun Zhang ◽  
Yong Bin Jia ◽  
Xi Lin Lu
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Finite Element Model ◽  
Concrete Columns ◽  
Element Model ◽  
Rc Frame ◽  
Ansys Software ◽  
Rc Columns ◽  
Monotonic Load ◽  
Inclined Cracks

The principle and processof finite element model of ANSYS software for RC frame column was introduced firstly,and then the cracking and development rules of RC columns under monotonic load were analyzed with ANSYSsoftware. The results show that: with the stirrup ratios increasing, the short columnwith rectangle hoop, rectangle cross brace hoop and tic tac toe stirrups appearsuccessively few inclined cracks and more vertical cracks; with the axialcompression ratio increasing, more length of horizontal cracks extend to naturalaxis, more vertical cracks appear and appeared cracks are higher along thecolumn height direction for middle length HSC frame columns; the length of OSCframe columns is not so long than that of HSC frame columns, and the crack distributionis dense and crack forms mesh, which show better ductility.

Mechanism of Frictional Mortar-Less Panel and its Application in Reinforcement Concrete Frame

2014 ◽  
Vol 894 ◽  
pp. 82-86
Author(s):  
Xiao Hong Zhou
Keyword(s):  
Finite Element ◽  
Seismic Behavior ◽  
Horizontal Displacement ◽  
Frame Structure ◽  
Rc Frame ◽  
Base Shear ◽  
Concrete Frame ◽  
Rc Frame Structure ◽  
Story Drift ◽  
Considerable Benefit

In order to improve the seismic behavior of the reinforcement concrete frame, a frictional mortar-less panel (FMP) was researched. In this masonry, the bricks are built without mortar and the lateral capability is supported by the friction between bricks. FMP has less rigid in-plane contribution, and contribute mostly to the energy dissipation of structure. To investigate the seismic behavior of FMP, a simple finite element modeling method has been proposed and verified with ANSYS. After that, the FMP was infilled in a typical reinforcement concrete frame structure and a Taft wave has been applied to research on its seismic behavior. The horizontal displacement, story drift, acceleration and base shear/axial force of RC frame has been achieved, results showed the FMP has considerable benefit to the seismic behavior of RC frame structure and worth to be promoted.

scholarly journals Multi-Platform Simulation of Infilled Shear-Critical Reinforced Concrete Frames Subjected to Earthquake Excitations

2021 ◽  
Author(s):  
Xu Huang ◽  
Alex Brodsky
Keyword(s):  
Reinforced Concrete ◽  
Shear Failure ◽  
Simulation Method ◽  
Fe Model ◽  
Nonlinear Behaviour ◽  
Rc Frame ◽  
Seismic Performance Assessment ◽  
Infill Wall ◽  
Rc Frames ◽  
Macro Modeling

Abstract This paper proposes a multi-platform simulation method for seismic performance assessment of masonry infilled reinforced concrete (RC) frames, especially for those who tend to fail in shear during an earthquake due to inadequate reinforcing details. The method is based on a micro-macro modeling approach where a detailed finite element (FE) model of the RC frame is incorporated with a strut model of the infill wall. It takes advantage of the strut model in terms of computational efficiency and the FE model based on the Modified Compression Field Theory (MCFT) to capture the nonlinear behaviour of the RC frame with explicit modeling of the beam-column joint failure and shear failure of the frame. The proposed method is validated against previously tested frames subjected to lateral loads, and its advantages over the conventional struct models are demonstrated through both quasi-static and dynamic analyses.

scholarly journals Influence of Infill Wall Configuration on Failure Modes of RC Frames

2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Xiaojie Zhou ◽  
Xiaoyuan Kou ◽  
Quanmin Peng ◽  
Jintao Cui
Keyword(s):  
Bearing Capacity ◽  
Rc Frame ◽  
Infill Wall ◽  
Bearing Capacity Ratio ◽  
Short Column ◽  
Shear Span ◽  
Capacity Ratio ◽  
Rc Frames ◽  
Shear Bearing Capacity ◽  
Lateral Constraint

An improper configuration of masonry infill walls in RC frame may lead to short column effect on the columns, which is harmful to the seismic behavior of the structure. In this study, a bare frame and two single-story, single-bay RC frames, partially infilled with masonry, were tested under cyclic loading. The failure mechanism and seismic performance of these partially infilled RC frames (with an infill height of 600 mm) with different types of connections were analysed. Based on the experiment, nonlinear finite element simulation and analysis were conducted to study the effects of the infill walls and connections. The results show that both mechanical performance and failure mode are affected by the infill height, the type of connection between the frame and the infill, and the ratio of shear bearing capacity of the frame column to that of the infill. For the masonry-infilled frame with rigid connection, the higher the infill wall is, the lower the shear bearing capacity ratio will be. Thus, the effect of the lateral constraint of the infill wall on the column increases, and the shear span ratio of the free segment of the column decreases, resulting in the short column effect. Based on the analysis results, a value of 2.0 is suggested for the critical shear bearing capacity ratio of the frame column to the infill wall. If the shear bearing capacity ratio is less than 2.0 and the shear span ratio of the column free segment is not more than 2.0, the short column effect will occur. For the infilled frame with flexible connection, both the lateral constraint from the wall to the column and the wall-frame interaction decrease; this reduces or prevents the short column effect. The conclusion can present guidance for the design and construction of masonry-infilled RC frame structure.

Sign in / Sign up

Export Citation Format

Share Document