scholarly journals Experimental and Numerical Analysis of Hollow and Solid Reinforced Concrete Piers under Static and Impact Loadings

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Pengfei Yao ◽  
Junyu Zhu ◽  
Lu Zhu ◽  
Hai Fang ◽  
Changgen Qian
Keyword(s):  
Reinforced Concrete ◽  
Failure Mode ◽  
Failure Modes ◽  
Impact Force ◽  
Impact Load ◽  
Experimental Results ◽  
Impact Behavior ◽  
Low Velocity ◽  
Process Failure ◽  
Damage Process

Collision on reinforced concrete (RC) piers by moving vessels or vehicles is a significant issue. This paper presents the static and impact behavior of RC piers with different hollow ratios. Three specimens were statically tested to obtain the load-displacement response. Low-velocity collision on eleven RC piers was conducted under the same velocity of 2.42 m/s. The damage process, failure mode, and force response were comprehensively analyzed. The experimental results indicate that the hollow ratio plays a significant role in the failure mode and ultimate load of RC piers under static and impact loadings. For RC piers with a hollow ratio of 0 and 0.4, the global failure dominated the damage process. However, failure of piers with a hollow ratio of 0.6 was governed by the local damage near the loading point. The static load capacities of the RC piers with a hollow ratio of 0.4 and 0.6 were 1.27% and 60.5% smaller than that of the solid pier, respectively. RC piers with a higher hollow ratio or lighter drop weight suffer smaller peak impact force. The increase of the longitudinal reinforcements leads to a promotion of the peak and mean impact force. Furthermore, the numerically predicted failure modes and impact load response show satisfactory agreement with the experimental results.

Seismic assessment of reinforced concrete columns with short lap splices

2021 ◽  
pp. 875529302199483
Author(s):  
Eyitayo A Opabola ◽  
Kenneth J Elwood
Keyword(s):  
Reinforced Concrete ◽  
Failure Mode ◽  
Failure Modes ◽  
Concrete Columns ◽  
Seismic Assessment ◽  
Rc Columns ◽  
Lap Splices ◽  
Displacement Response ◽  
Force Displacement ◽  
Probable Failure

Existing reinforced concrete (RC) columns with short splices in older-type frame structures are prone to either a shear or bond mechanism. Experimental results have shown that the force–displacement response of columns exhibiting these failure modes are different from flexure-critical columns and typically have lower deformation capacity. This article presents a failure mode-based approach for seismic assessment of RC columns with short splices. In this approach, first, the probable failure mode of the component is evaluated. Subsequently, based on the failure mode, the force–displacement response of the component can be predicted. In this article, recommendations are proposed for evaluating the probable failure mode, elastic rotation, drift at lateral failure, and drift at axial failure for columns with short splices experiencing shear, flexure, or bond failures.

scholarly journals Behavior of wood beam connection using staples subjected to in-plane moment

2019 ◽  
Vol 258 ◽  
pp. 05008
Author(s):  
Farida Lenggani ◽  
Bambang Suryoatmono
Keyword(s):  
Failure Mode ◽  
Failure Modes ◽  
Solid Wood ◽  
Experimental Results ◽  
Elastic Analysis ◽  
Connection Strength ◽  
Test Results ◽  
Lateral Resistance ◽  
Wood Beams ◽  
Mechanical Fasteners

It is very frequent that solid wood beams need to be connected one to another to obtain a longer beam. In this study, the behavior of solid wood beams connections using plywood sheets as connecting elements and staples as mechanical fasteners were studied experimentally. The experimental results were compared with elastic analyses. Both beam and plywood were made of meranti (shorea). The staple type was MAX 1022J. This study was conducted on two specimens. The first specimen had two rows of staples on the front and back sides of the specimen. Each row consisted of ten staples making a total of 40 staples. The second one had three rows of staples on the front and back sides of the specimen. Each row consisted of ten staples making a total of 60 staples. From the tests, it can be concluded that each material in the connection, namely wood beam, plywood, and staples, failed. Failure mode of the wood beam was in the form of crack and tear. Failure mode of the plywood was the damage of the plywood directly contacted with the crown of the staples. Failure modes of the staples were flexural yielding. The differences between connection strength obtained from tests and elastic analyses were 8.18% for the first specimen and 0.65% for the second specimen, with the test results were higher than the elastic analyses results. It can be concluded that elastic analysis is quite accurate and conservative to estimate the strength of this type of connection, provided that the lateral resistance of connection with a staple is known.

Lab-scale evaluations on formation of products of incomplete combustion in hazardous waste incineration: influence of process variables

1997 ◽  
Vol 36 (11) ◽  
pp. 219-226 ◽  
Author(s):  
G. Mascolo ◽  
L. Spinosa ◽  
V. Lotito ◽  
G. Mininni ◽  
G. Bagnuolo
Keyword(s):  
Failure Mode ◽  
Failure Modes ◽  
Waste Incineration ◽  
Process Variables ◽  
Thermal Failure ◽  
Process Failure ◽  
Toxic Organics ◽  
Laboratory Investigations ◽  
Hazardous Waste Incineration ◽  
Products Of Incomplete Combustion

Laboratory investigations have been carried out to study the influence of process failure modes on organics emission during the incineration of hazardous sludge. The thermal, temporal and fuel-oxidant mixing failure modes were tested. They were simulated by holding the first combustion temperature at 400°C and varying the after-burning one between 600 and 1100°C, the after-burning residence time between 1 and 3 s and the excess air between 30 and 160%. Results showed that the thermal failure mode is the most important factor controlling the number and concentration of emitted organics leading to the formation of over 70 compounds at after-burning temperature of 600°C. At higher after-burning temperatures emissions are controlled by the fuel-oxidant mixing failure mode and, only when the after-burning is 800°C and the oxygen is 160% over the stoichiometric value, by the temporal failure mode. Based on results obtained some suggestions for reducing emissions of toxic organics in full-scale incinerators are given.

Computational Study of Lateral Impact Behavior of Pressurized Pipelines

2013 ◽  
Author(s):  
Yangqing Dou ◽  
Yucheng Liu
Keyword(s):  
Failure Modes ◽  
Computational Study ◽  
Dynamic Responses ◽  
Impact Behavior ◽  
Lateral Impact ◽  
Low Velocity ◽  
Collapse Mechanisms ◽  
Safety And Reliability ◽  
Crashworthiness Analysis ◽  
Pressurized Pipelines

This paper presents a computational study to investigate the crash responses and collapse mechanisms of pipelines subjected to lateral impact. Influence of internal pressure of the pipelines on their lateral impact behavior is revealed through a serious of numerical crashworthiness analysis. FEA software package, LS-DYNA, is used to model the pressurized pipelines and perform the crashworthiness analysis. The simulation results provide a substantial background for the future experimental study to completely investigate dynamic responses and failure modes of pipelines subjected to low-velocity lateral impact. The results presented in this paper also have potential benefits on research of safety and reliability of civil pipelines and development of advanced pipelines materials.

Risk Evaluation Approach in Failure Mode and Effect Analysis of Automotive Headlamp Assembly

2014 ◽  
Vol 564 ◽  
pp. 72-76
Author(s):  
Shukriah Abdullah ◽  
Aziz Abdul Faieza
Keyword(s):  
Failure Mode ◽  
Failure Modes ◽  
Assessment Tool ◽  
Action Plan ◽  
Technical Problem ◽  
Assembly Process ◽  
Preventive Action ◽  
Effect Analysis ◽  
Evaluation Approach ◽  
Process Failure

Headlamp assembly entailed a complex assembly process and error in assembled can result in technical problem and higher reject rate at the end of the assembly process. A study has been conducted, in one of the automotive headlamp assembly in Malaysia, where there are numerous defect detected during the assembly process, such as metal spacing missing, wrong model housing, wrong sticker affix, wrong orientation with a total of 80% defects detected. Currently the headlamps are assembled with no dimensional control, results in high physical nonconformity product. The main objective of this project is to identify potential failure in headlamp assembly process. The approach used was risk assessment tool which is Process Failure Mode and Effect. This work also developed the corrective action plan for accurate ranking of Failure Modes by Risk Priority Number-based method and implement it to the process assembly. The result showed that there was increased of 5% in preventive action and 4% increment of the detection action

scholarly journals Structural Behavior of Reinforced Self-Compacted Engineered Cementitious Composite Beams

2016 ◽  
Vol 2016 ◽  
pp. 1-12 ◽  
Author(s):  
Bashar S. Mohammed ◽  
M. F. Nuruddin ◽  
Muhammad Aswin ◽  
Nursyuhada Mahamood ◽  
Hashem Al-Mattarneh
Keyword(s):  
Reinforced Concrete ◽  
Large Scale ◽  
Concrete Beam ◽  
Failure Modes ◽  
Reinforced Concrete Beam ◽  
Composite Beams ◽  
Experimental Results ◽  
Structural Behavior ◽  
Cementitious Composite ◽  
Engineered Cementitious Composite

Eight large-scale reinforced self-compacted engineered cementitious composite (R-SC-ECC) beams with different steel reinforcement ratios have been designed, prepared, cast, cured, and tested to failure at the age of 28 days. The experimental results have been compared with theoretical values predicted using EC2, RILEM, and VecTor2 models. Results show that failure modes in flexure and shear of R-SC-ECC beams are comparable to that of normal reinforced concrete beam. Nevertheless, contrary to VecTor2, models of EC2 and RILEM are not suitable for predicting reasonable ultimate moments for the beams, while results using VecTor2 model have successfully predicted the failure modes and load-deflection curves for all R-SC-ECC beams. It has been concluded that R-SC-ECC fall in the category of ductility class medium to high which gives advantages of using R-SC-ECC beams in regions susceptible to seismic activities.

scholarly journals Performance based design of reinforced concrete beams under impact

2010 ◽  
Vol 10 (6) ◽  
pp. 1069-1078 ◽  
Author(s):  
S. Tachibana ◽  
H. Masuya ◽  
S. Nakamura
Keyword(s):  
Reinforced Concrete ◽  
Collision Energy ◽  
Concrete Beams ◽  
Impact Load ◽  
Experimental Results ◽  
Reinforced Concrete Beams ◽  
Performance Based Design ◽  
Impact Action ◽  
The Impact ◽  
A Performance

Abstract. The purpose of this research is to collect fundamental data and to establish a performance-based design method for reinforced concrete beams under perpendicular impact load. Series of low speed impact experiments using reinforced concrete beams were performed varying span length, cross section and main reinforcement. The experimental results are evaluated focusing on the impact load characteristics and the impact behaviours of reinforced concrete beams. Various characteristic values and their relationships are investigated such as the collision energy, the impact force duration, the energy absorbed by the beams and the beam response values. Also the bending performance of the reinforced concrete beams against perpendicular impact is evaluated. An equation is proposed to estimate the maximum displacement of the beam based on the collision energy and the static ultimate bending strength. The validity of the proposed equation is confirmed by comparison with experimental results obtained by other researchers as well as numerical results obtained by FEM simulations. The proposed equation allows for a performance based design of the structure accounting for the actual deformation due to the expected impact action.

Implication of Unbondedness in Reinforced Concrete Beams

2012 ◽  
Vol 587 ◽  
pp. 36-41 ◽  
Author(s):  
S.F.A. Rafeeqi ◽  
S.U. Khan ◽  
N.S. Zafar ◽  
T. Ayub
Keyword(s):  
Shear Strength ◽  
Reinforced Concrete ◽  
Failure Mode ◽  
Shear Failure ◽  
Concrete Beams ◽  
Experimental Results ◽  
Reinforced Concrete Beams ◽  
Rc Beams ◽  
Flexural Capacity ◽  
Flexural Reinforcement

In this paper, behaviour of nine (09) RC beams (including two control beams) after unbonding and exposing flexural reinforcement has been studied which were intentionally designed and detailed to observe flexural and shear failure. Beams have been divided into three groups based on failure mode and unbounded and exposed reinforcement. Beams have been tested under two-point loading up to failure. Experimental results are compared in terms of beam behaviour with respect to flexural capacity and failure mode which revealed that the exposed reinforcement does not altered flexural capacity significantly and unbondedness positively influences shear strength; however, serviceability performance of beams with unbonded and exposed reinforcement is less.

Punching in two-way RC flat slabs with openings and L section columns

2019 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Valdemir Colares Pinto ◽  
Vitor Branco ◽  
Denio Ramam Oliveira
Keyword(s):  
Reinforced Concrete ◽  
Cross Section ◽  
Failure Modes ◽  
Computational Simulation ◽  
Experimental Results ◽  
Design Codes ◽  
Nonlinear Simulation ◽  
Content Type ◽  
Flat Slabs ◽  
Failure Loads

Purpose This study aims to contribute to a better understanding of the influence of the position of openings around L cross-section columns in reinforced concrete flat slabs through a nonlinear computational analysis compared to experimental results. Design/methodology/approach Tests on four reinforced concrete flat slabs of 1800 x 1800 x 120 mm3 were carried out under symmetrical punching; one slab was referenced (without hole) and three had square holes of 100 x 100 mm2 close to columns and with centroid on the critical perimeter at 0.5 d and 2.0 d of the loaded area. A nonlinear analysis of the slabs was performed to aid the interpretation and preview of the experimental results, and to estimate the ultimate loads and failure modes. These estimates followed recommendations of ACI 318, Eurocode 2, NBR 6118, MC 2010 and critical shear crack theory. Findings The results showed that the presence of holes in the analyzed regions does not influence significantly the behavior of the slabs, leading to conservative structural design once the ultimate load estimates are low, while the computational results adequately estimated the slabs’ behavior. Research limitations/implications A few limitations were observed on how to implement the correct modeling system for computational nonlinear simulation. Practical implications All design codes underestimated failure loads and the theoretical method was not much better. The nonlinear computational simulations were satisfactory, presenting results close to experimental ones (97 per cent accuracy). Computational simulation also showed that the presence of holes does not significantly influence the load-vertical displacement behavior or failure loads. Social implications Structural and civil engineers and designers can observe with better details the punching phenomenon and make take secure decisions to building projects. They can preview accurate cases that are not cited in design codes and literature. Originality/value This is a very rare subject in literature that interests the entire scientific community and especially reinforced concrete designers. Presenting a new methodology to nonlinear flat slab with openings modeling to punching shear provoked by L cross section columns, case that is not cited in literature and design codes.

Compression after impact behavior of titanium honeycomb sandwich structures

2017 ◽  
Vol 20 (5) ◽  
pp. 639-657 ◽  
Author(s):  
Wei Zhao ◽  
Zonghong Xie ◽  
Xiang Li ◽  
Xishan Yue ◽  
Junfeng Sun
Keyword(s):  
Failure Modes ◽  
Sandwich Structures ◽  
Impact Damage ◽  
Sandwich Panels ◽  
Low Velocity Impact ◽  
Impact Behavior ◽  
Failure Strength ◽  
Compressive Failure ◽  
Low Velocity ◽  
Honeycomb Sandwich

Titanium honeycomb sandwich structures are gradually used in several newly developed aircrafts in China. During the manufacturing process and aircraft service life, low-velocity impacts from foreign objects (typically stones, tools and hails, etc.), would quite likely happen and could not be completely avoided. In order to evaluate the influence of low-velocity impact damage on titanium honeycomb sandwich structures, unidirectional in-plane compression tests on both intact and impact damaged sandwich panels were conducted to obtain their failure modes and compressive failure strength. Test results showed that the low-velocity impact damage could cause the change in failure modes and a 9% to 15% decrease in the compressive failure strength. Different impact energy levels showed a limited influence on the compressive failure strength. Numerical analysis was conducted to study the compression after impact behavior of titanium sandwich panels. Parametric finite element models that contained all the geometric and the structural details of honeycomb core cells, as well as the indentation and the crushed core region, were developed in the analysis. The numerical results successfully exhibited the failure process of the intact and impact damaged titanium sandwich panels subjected to unidirectional in-plane compression, similar to what observed in the tests. The predicted compressive failure strength also agreed very well with the test data.

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