scholarly journals Recycling of damaged RC frames: Replacing crumbled concrete and installing steel haunches below/above the beam at connections

2021 ◽  
Vol 54 (4) ◽  
pp. 282-298 ◽  
Author(s):  
Naveed Ahmad ◽  
Arifullah ◽  
Babar Ilyas ◽  
Sida Hussain
Keyword(s):  
Numerical Model ◽  
High Strength ◽  
Finite Element Program ◽  
Displacement Capacity ◽  
Rc Frames ◽  
Lateral Resistance ◽  
Story Drift ◽  
Response History Analysis ◽  
Element Program ◽  
Original Frame

Experimental and numerical studies are presented evaluating the efficacy of a recycling technique applied to a 1:3 reduced scale damaged RC frame. The crumbled concrete at the beam-column connections was replaced with new high-strength concrete. Epoxy mortar was applied at the interface to secure bonding between the old and new concrete. Additionally, the connections were provisioned with steel haunches, applied below and above the beams. The retrofitted frame was tested under quasi-static cyclic loads. The lateral resistance-displacement hysteretic response of the tested frame was obtained to quantify hysteretic damping, derive the lateral resistance-displacement capacity curve, and develop performance levels. The technique improved the response of the frame; exhibiting an increase in the lateral stiffness, resistance and post-yield stiffness of the frame in comparison to the undamaged original frame. This good behaviour is attributed to the steel haunches installed at connections. A representative numerical model was calibrated in the finite element program SeismoStruct. A set of spectrum compatible ground motions were input to the numerical model for response history analysis. The story drift demands were computed for both the design basis and maximum considered earthquakes. Moreover, the technique was extended to a five-story frame, which was evaluated through nonlinear static pushover and response history analyses. Overstrength factor WR = 4.0 is proposed to facilitate analysis and preliminary design of steel haunches and anchors for retrofitting the low-/mid-rise RC frames.

First Results of a 3D Pull-Out Model of Steel Anchors in Fired-Clay Bricks

2019 ◽  
Vol 817 ◽  
pp. 514-519 ◽  
Author(s):  
Francesco Finelli ◽  
Angelo Di Tommaso ◽  
Cristina Gentilini
Keyword(s):  
Numerical Simulation ◽  
Finite Element ◽  
Numerical Model ◽  
Experimental Results ◽  
Clay Brick ◽  
Finite Element Program ◽  
Clay Bricks ◽  
Pull Out ◽  
First Results ◽  
Element Program

The paper reports the results of a numerical simulation performed to study the experimental pull-out behavior of twisted steel connectors inserted in fired-clay brick units. The experimental results obtained in a previous campaign are used to calibrate a 3D refined numerical model developed by means of the finite element program Abaqus. The numerical model is tuned to accurately reproduce the experimental results in terms of loads and bar displacements.

Experimental and Numerical Study of Laterally Loaded Pile Groups with Pile Caps at Variable Elevations

2000 ◽  
Vol 1736 (1) ◽  
pp. 12-18 ◽  
Author(s):  
Michael C. McVay ◽  
Limin Zhang ◽  
Sangjoon Han ◽  
Peter Lai
Keyword(s):  
Numerical Study ◽  
Ground Surface ◽  
Pile Group ◽  
Special Device ◽  
Pile Groups ◽  
Finite Element Program ◽  
Lateral Resistance ◽  
Pile Cap ◽  
Element Program ◽  
Pile Caps

A series of lateral load tests were performed on 3×3 and 4×4 pile groups in loose and medium-dense sands in the centrifuge with their caps located at variable heights to the ground surface. Four cases were considered: Case 1, pile caps located above the ground surface; Case 2, bottom of pile cap in contact with the ground surface; Case 3, top of pile cap at the ground surface elevation; and Case 4, top of pile cap buried one cap thickness below ground surface. All tests with the exception of Case 1 of the 4×4 group had their pile tips located at the same elevation. A special device, which was capable of both driving the piles and raining sand on the group in flight, had to be constructed to perform the tests without stopping the centrifuge (spinning at 45 g). The tests revealed that lowering the pile cap elevation increased the lateral resistance of the pile group anywhere from 50 to 250 percent. The experimental results were subsequently modeled with the bridge foundation-superstructure finite element program FLPIER, which did a good job of predicting all the cases for different load levels without the need for soil–pile cap interaction springs (i.e., p-y springs attached to the cap). The analyses suggest that the increase in lateral resistance with lower cap elevations may be due to the lower center of rotation of the pile group. However, it should be noted that this study was for pile caps embedded in loose sand and not dense sands or at significant depths. The experiments also revealed a slight effect for the case of the pile cap embedded in sand with a footprint wider than the pile row. In that case the size of the passive soil wedge in front of the pile group, and consequently the group’s lateral resistance, increased.

scholarly journals Mechanical Properties Of The Ceramic Open-Cell Foams Of Variable Cell Sizes

2015 ◽  
Vol 60 (3) ◽  
pp. 1957-1964 ◽  
Author(s):  
Z. Nowak ◽  
M. Nowak ◽  
R.B. Pęcherski ◽  
M. Potoczek ◽  
R.E. Śliwa
Keyword(s):  
Mechanical Properties ◽  
Numerical Model ◽  
Compression Test ◽  
Young Modulus ◽  
Vertical Displacement ◽  
Finite Element Program ◽  
Open Cell ◽  
Open Cell Foam ◽  
Element Program ◽  
Deformation Processes

AbstractThe mechanical properties and numerical model of ceramic alumina open-cell foam, which is produced by the chemical method of gelcasting with different cell sizes (porosities) are presented. Geometric characteristics of real foam samples were estimated from tomographic and scanning electron microscopy images. Using this information, numerical foam model was proposed. A good agreement between the numerical model and the results elaborated from microtomography was obtained. To simulate the deformation processes the finite element program ABAQUS was used. The main goal of this computation was to obtain macroscopic force as a function of applied vertical displacement in compression test.As a result of numerical simulation of compression test of alumina foam for different values of porosity, the Young modulus and the strength of such foams were estimated.

scholarly journals Numerical Modeling of GFRP Reinforced Concrete Slabs

2017 ◽  
Vol 1 (4) ◽  
Author(s):  
Omer R EL Zaroug, John P Forth, Jianqiao YE
Keyword(s):  
Finite Element ◽  
Mechanical Load ◽  
Weight Ratio ◽  
High Strength ◽  
Load Range ◽  
Finite Element Program ◽  
Reinforced Concrete Slabs ◽  
Reinforced Polymer ◽  
Element Program ◽  
Fibre Reinforced Polymer

The use of non-metallic fibre reinforced polymer reinforcement as an alternative to steel reinforcement in concrete is gaining acceptance mainly due to its high corrosion resistance. High strength-to-weight ratio, high stiffness-to-weight ratio and ease of handling and fabrication are added advantages. Other benefits are that they do not influence to magnetic fields and radio frequencies and they are thermally non-conductive. However, the stress-strain relationship for Glass fibre reinforced polymer reinforcement (GFRP) is linear up to rupture when the ultimate strength is reached. Unlike steel reinforcing bars, GFRP rebars do not undergo yield deformation or strain hardening before rupture. Also, GFRP reinforcement possesses a relatively low elastic modulus of elasticity compared with that of steel. As a consequence, for GFRP reinforced sections, larger deflections and crack widths are expected than the ones obtained from equivalent steel reinforced sections for the same load. This investigation provides details of the numerical analysis of GFRP reinforced slabs loaded mechanically using the commercial finite element program (DIANA). To prove the validity of the proposed finite element approach, a comparison is made with experimental test results obtained from full-size slabs. The comparisons are made on the basis of first cracking load, load-deflection response at midspan, cracking patterns, mode of failure and loads at failure. Using the DIANA software for the analysis of GFRP reinforced slabs under mechanical load is possible and can produce acceptable predictions throughout the load range in terms of final load and crack patterns. However, DIANA overestimated the first cracking load and tended to over predict the experimental deflections.  

Nonlinear Analysis of Steel Reinforced High Strength and High Performance Concrete Eccentric Columns

2010 ◽  
Vol 450 ◽  
pp. 223-226 ◽  
Author(s):  
Shan Suo Zheng ◽  
Wei Wang ◽  
Bin Wang ◽  
Lei Li ◽  
Yi Hu
Keyword(s):  
High Performance ◽  
High Performance Concrete ◽  
Numerical Models ◽  
Constitutive Models ◽  
High Strength ◽  
Failure Criteria ◽  
Experimental Results ◽  
Finite Element Program ◽  
Calculation Results ◽  
Element Program

According to experiment of four steel reinforced high strength and high performance concrete(SRHSHPC) columns with different eccentricity, this paper establishes four equally parameter numerical models by finite element program ANSYS. The failure mechanism, failure mode and mechanical behaviors of the SRHSHPC columns with large and small eccentricity can be revealed by comparing the numerical simulation results with the corresponding experimental results. And the approximate plane-section assumption in SRHSHPC eccentric columns is verified by the study of the relationship between load and strain. It is shown that when constitutive models and failure criteria of SRHSHPC and steel are in precise case, the calculation results agree well with the corresponding experimental results.

Analysis of Bearing Capacity of Steel-High Strength Concrete Composite Beams

2013 ◽  
Vol 838-841 ◽  
pp. 661-664
Author(s):  
Liang Li Xiao ◽  
Ming Yang Pan ◽  
Jian Wei Han
Keyword(s):  
Bearing Capacity ◽  
High Strength Concrete ◽  
Influence Factors ◽  
High Strength ◽  
Composite Beams ◽  
Finite Element Program ◽  
Strength Concrete ◽  
Element Program ◽  
Negative Moment ◽  
Negative Bending

It is very crucial to analyze the flexural bearing capacity of the steel-high strength concrete composite beams, but the combination on the flange of steel beam and their bearing capacity is limited with certain inevitability,in addition, in the negative bending regions of continuous composite beams, with the constant increase of load, the process of the whole structure will cause damages in the negative moment region. In order to avoid this kind of damages, we must use general finite element program ANSYS to analyze thebearing capacity of the steel and high strength concrete composite beams. Besides further studying the influence factors of bearing capacity, and ensuring the safety of our engineering performance can be in favor of the engineering structure.

Microstructure Modeling as a Tool to Optimize Forging of Critical Aircraft Parts

2004 ◽  
Vol 467-470 ◽  
pp. 683-688 ◽  
Author(s):  
Martin Stockinger ◽  
Johann Tockner
Keyword(s):  
Finite Element ◽  
High Strength ◽  
Strain Rates ◽  
Process Data ◽  
Finite Element Program ◽  
Microstructure Modeling ◽  
Forged Parts ◽  
Element Program ◽  
Nickel Base ◽  
Grain Growth Behavior

Forging of high strength nickel base superalloys 720 and 718 for aircraft parts requires the usage of finite element simulations to ensure a proper thermo-mechanical treatment. Because of the strong mechanical requirements and narrow specifications of such parts not only a correct, defect free final geometry is necessary, but also a defined microstructure. The crucial point is therefore, to control all process parameters in a way to achieve the demanded properties. The typical forging processes like hydraulic, screw press and hammer forging imply a broad spectrum of strain rates. The influence of this different strain rates as well as forging temperature and strain on dynamic and post-dynamic recrystallization have been examined experimentally. Annealing tests at various temperatures and time periods have been performed, to investigate the grain growth behavior and dissolution processes in this before mentioned materials during heating periods. The obtained data was used to build phenomenological models, which were implemented into finite element code of a commercial special purpose finite element program. 2D and 3D Simulations of multiple step thermo-mechanical processes are compared with microstructure examinations of forged parts to show the usability and accuracy of such models as a tool to optimize complex forging processes of critical aircraft parts. In combination with systematic process data collection during production a stable processes and satisfactory mechanical product properties are guaranteed.

Finite Element Analysis of Axially Loaded RPC Filled Long Circular Steel Tube Columns

2013 ◽  
Vol 779-780 ◽  
pp. 352-355
Author(s):  
Zhi Gang Yan ◽  
Jun Yang ◽  
Hua Luo
Keyword(s):  
Finite Element ◽  
Slenderness Ratio ◽  
High Strength ◽  
Steel Tube ◽  
Element Analysis ◽  
Finite Element Program ◽  
Circular Steel Tube ◽  
Element Program ◽  
Reactive Powder ◽  
Structural Engineers

In recent years, Reactive Powder Concrete (RPC) has been concerned by the structural engineers and researchers. RPC is a kind of cement-based composite which has ultra-high strength, high ductility and durability, however, it has great fragility. The fragility performance of RPC will be improved if RPC and steel are put together as RPC-filled steel tube circular stub columns. The aim of this paper is to develop accurate finite element models to simulate the behavior of RPC-filled steel tube circular long columns. The finite element program ABAQUS is used in the analysis. An extensive parametric study is conducted to investigate the effects of different slenderness ratio and confinement action on the strength and behavior of RPC-filled steel tube circular long columns. The results obtained from the models are verified against the results of the tests. The results show that the rising part of load-strain curves are in good agreements with experiment results.

Slenderness effects in high-strength concrete columns

1991 ◽  
Vol 18 (5) ◽  
pp. 765-771 ◽  
Author(s):  
Antoine E. Lahoud
Keyword(s):  
High Strength Concrete ◽  
High Strength ◽  
Concrete Columns ◽  
Finite Element Program ◽  
Strength Concrete ◽  
High Rise ◽  
Element Program ◽  
Normal Strength ◽  
Slender Columns

High-strength concretes are being increasingly used in the columns of high-rise buildings. Analytical studies of the slenderness effects in these columns have been very limited. The behavior of slender columns with normal- and high-strength concretes is studied using a finite element program. Differences and similarities in long-term and short-term behaviors between high-strength and normal-strength slender concrete columns are noted and discussed. Key words: columns, slenderness, high-strength concrete, creep, finite elements.

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