Experimental Studies on Blast-Resistance of HFR-LWC Beams Enhanced with Membrane Action

2020 ◽  
Vol 20 (12) ◽  
pp. 2050142
Author(s):  
Wanxiang Chen ◽  
Lisheng Luo ◽  
Fanjun Meng ◽  
Hang Sun
Keyword(s):  
Failure Modes ◽  
Blast Resistance ◽  
Experimental Studies ◽  
Field Tests ◽  
Lightweight Aggregate ◽  
Failure Pattern ◽  
Lightweight Aggregate Concrete ◽  
Hybrid Fibers ◽  
Membrane Action ◽  
Close Range

Support-induced membrane action can enhance the resistance, while altering the failure pattern, of reinforced concrete (RC) members under static/dynamic loadings. Nevertheless, the membrane effect on the load-response is regarded as a safety factor in current design guides, hence, a thorough understanding of the resistance capability of RC members in the presence of membrane actions is considered essential. To quantitatively depict the membrane behavior and its influence on the blast-resistance and failure pattern of Hybrid Fiber Reinforced-Lightweight Aggregate Concrete (HFR-LWC) beams, a specially built end-constraint clamp is developed to provide membrane actions on the structural component subjected to the blast load simultaneously. A series of field tests are conducted to investigate the dynamic behaviors of the HFR-LWC beams under close-range detonations. Overpressure-time histories of shock waves induced by the close-range explosive charge are captured. Then the deflection-responses and failure modes of the HFR-LWC beams are further investigated. The responses of the clamped HFR-LWC beam under blast loadings can be well simulated, and the blast-resistances of the beam-type members with membrane action are evaluated reasonably. The results show that membrane action is beneficial for the bridging effects of hybrid fibers and the interlocking effects of coarse aggregate, thereby giving rise to the ductile failures of HFR-LWC beam. The maximum deflections of the clamped HFR-LWC beam decrease by about 60% compared with simply-supported HFR-LWC beam in this paper, illustrating that the blast-resistance may be seriously underestimated if the membrane effects are ignored in structural design.

scholarly journals Evaluation of Stress–Strain Behavior of Self-Compacting Rubber Lightweight Aggregate Concrete under Uniaxial Compression Loading

Materials ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4064 ◽  
Author(s):  
Jing Lv ◽  
Tianhua Zhou ◽  
Qiang Du ◽  
Kunlun Li ◽  
Kai Sun
Keyword(s):  
Compressive Strength ◽  
Failure Modes ◽  
Experimental Studies ◽  
Lightweight Aggregate ◽  
Lightweight Aggregate Concrete ◽  
Peak Strain ◽  
Stress Strain ◽  
Aggregate Concrete ◽  
Rubber Particles ◽  
Strain Relationship

The recycling of waste tires in lightweight aggregate concrete (LC) would achieve huge environmental and societal benefits, but the effects of rubber particles on the partial properties of LC are not clear (e.g., the stress–strain relationship). In this paper, uniaxial compressive experiments were conducted to evaluate the stress–strain relationship of self-compacting rubber lightweight aggregate concrete (SCRLC). Rubber particles were used to replace sand by volume, and substitution percentages of 0%, 10%, 20%, 30%, 40%, and 50% were set as influence factors. Experimental results indicate that with increased rubber particles substitution percentage, the cubic compressive strength and axial compressive strength of SCRLC decreased, while the failure modes of SCRLC prism specimens gradually changed from brittle to ductile failure. As the rubber particles substitution percentage increased from 0% to 50%, the peak strain of SCRLC increased whereas peak stress, elastic modulus, and peak secant modulus of SCRLC deceased, the descending stage of stress–strain curves became softer. The rubber particles substitution percentage of 30% was the critical point at which an obvious change in the properties of SCRLC occurred. Based on the data collected from experimental studies, a predictive model for SCRLC was established and a further prediction of the SCRLC stress–strain relationship was given.

scholarly journals Shear strength enhancement of lightweight aggregate reinforced concrete deep beams by using CFRP strips

2018 ◽  
Vol 162 ◽  
pp. 04011 ◽  
Author(s):  
Ahlam Mohammad ◽  
Kaiss Sarsam ◽  
Nabeel Al-Bayati
Keyword(s):  
Reinforced Concrete ◽  
Failure Modes ◽  
Ultimate Load ◽  
Lightweight Aggregate ◽  
Lightweight Aggregate Concrete ◽  
Shear Cracks ◽  
Deep Beams ◽  
Control Beam ◽  
Shear Span ◽  
Number Of Layers

In this research, results of an experimental investigation on the shear strengthening of lightweight aggregate reinforced concrete deep beams are presented. A total of eight lightweight aggregate deep beams were cast and tested in the experimental work to study the effect of externally bonded CFRP strips in improving their structural behavior, one of them was unstrengthened to serve as a control beam while the remaining seven beams were strengthened in different orientation, spacing and number of layers of CFRP. The locally available natural porcelanite rocks are used to seek the possibility of producing structural lightweight aggregate concrete. The beams were designed to satisfy the requirements of ACI 318M- 14 building code. Results show that the CFRP strips have increased the load carrying capacity for the strengthened deep beams up to 50 % when comparedto the unstrenghtened control one. The diagonal compression strut crack of unstrenghtened control beam is changed to several diagonal cracks in the mid-depth within the shear span of the strengthened beams and exhibited more ductile failure modes. The results also indicate that bonded CFRP system in the shear span was seen to delay the formation of diagonal shear cracks and provided positive restraint to the subsequent growth of cracks. Increasing the amount of CFRP (by increasing the number of layers from one to two layers) results in increase in the ultimate load by about 15%. However, the increase in the spacing between the strips (from 100 to 150mm) led to a decrease in the ultimate load by about 13%.

Freeze-Thaw Model and Service Life Prediction of Hybrid Fiber Reinforced Lightweight Aggregate Concrete

2011 ◽  
Vol 250-253 ◽  
pp. 817-821 ◽  
Author(s):  
Jun Fang Huo ◽  
Da Peng Liu ◽  
Xiang Dong Shen ◽  
Jian Jun Chu ◽  
De Tian Song
Keyword(s):  
Service Life ◽  
Frost Resistance ◽  
Life Prediction ◽  
Polypropylene Fiber ◽  
Lightweight Aggregate ◽  
Service Life Prediction ◽  
Lightweight Aggregate Concrete ◽  
Hybrid Fiber ◽  
Hybrid Fibers ◽  
Aggregate Concrete

The effect of the frost resistance on hybrid fibers reinforced lightweight aggregate concrete is investigated. And hybrid fibers reinforced lightweight aggregate is that steel fiber and polypropylene fiber are selected to incorporate into. The results indicate that, hybrid fibers reinforced lightweight aggregate concrete can improve the frost resistance. The weight loss rate of hybrid fibers reinforced lightweight aggregate concrete is not better. The research to establish a model for service life prediction of hybrid fibers reinforced lightweight aggregate concrete on experimental results has been done.

Evaluation of Operational Properties of Composite Reinforcement Used in Concrete Structures

2014 ◽  
Vol 880 ◽  
pp. 57-61
Author(s):  
Viktor V. Rodevich ◽  
Artem A. Ovchinnikov ◽  
Elena V. Shilnikova
Keyword(s):  
Experimental Studies ◽  
Basalt Fiber ◽  
Lightweight Aggregate ◽  
Alkali Resistance ◽  
Lightweight Aggregate Concrete ◽  
Performance Study ◽  
Building Envelopes ◽  
Satisfactory Performance ◽  
High Alkali ◽  
Composite Reinforcement

The paper is devoted to the study of composite reinforcement made of glass fiber and basalt fiber, in particular their operational properties under the aggressive alkaline lightweight aggregate concrete environment. Their thermal resistance being sufficiently less than that of the regular steel composites they may be used in three-layered building envelopes to provide enhanced thermal properties. However there is lack of data and experimental results on the topic. Previous research indicated high alkali resistance of basalt fiber reinforcement, but there is a need in further studies. For the objective of the composite reinforcement that is used as flexible connectors for layer wall panels, a series of experimental studies. Research data have shown satisfactory performance study of flexible links.

scholarly journals Close Range Explosive Loading on Steel Column in the Framework of Anisotropic Viscoplasticity

Metals ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 454 ◽  
Author(s):  
Sielicki ◽  
Sumelka ◽  
Lodygowski
Keyword(s):  
Experimental Studies ◽  
Field Tests ◽  
Explosive Loading ◽  
Point Of View ◽  
Computational Results ◽  
Computational Point ◽  
User Subroutine ◽  
Numerical Studies ◽  
Steel Column ◽  
Close Range

The research was based on data obtained from experimental studies and aims in thechallenge of mapping these results by a mathematical (phenomenological) model. The fieldexperiments were performed on an H-section steel column supported by a reinforced concretefoundation and subjected to a close-in explosion. Numerical studies were carried out usingAbaqus/Explicit code. The user subroutine VUMAT for metallic obstacle was also implemented,together with a coupled Eulerian–Lagrangian approach. The steel column failure recorded duringreal field tests versus computational results was examined and compared. It was crucial that, fromthe computational point of view, the obstacle reflected the generalized thermo-elasto-viscoplastic(GTEV) behavior of Perzyna’s type, including an anisotropic measure of damage.

Experimental Study on Dynamic Mechanical Properties of HPP Hybrid Fibers Reinforced Lightweight Aggregate Concrete

2014 ◽  
Vol 919-921 ◽  
pp. 1983-1989 ◽  
Author(s):  
Dan Wang ◽  
Zhi Kun Guo ◽  
Fei Shao ◽  
Wan Xiang Chen
Keyword(s):  
Mechanical Properties ◽  
Strain Rate ◽  
Lightweight Aggregate ◽  
Dynamic Mechanical Properties ◽  
Lightweight Aggregate Concrete ◽  
Compression Tests ◽  
Hybrid Fibers ◽  
Impact Compression ◽  
Aggregate Concrete ◽  
Dynamic Mechanical

The impact compression tests on HPP hybrid fibers reinforced lightweight aggregate concrete were performed with 100mm SHPB equipment. The dynamic mechanical properties and variation of HPP hybrid fibers reinforced lightweight aggregate concrete under different strain rates and loading methods were systematically studied. HPP hybrid fibers reinforced lightweight aggregate concrete is of the property of strain rate effects under impact loads as ordinary concrete. The dynamic strength and peak strain of it increased with the increase of strain rate. During multiple-impact compression tests, the specimens were able to bear multiple impacts before damage after cracks were produced. It is clear that HPP hybrid fibers reinforced lightweight aggregate concrete is an outstanding material for protective engineering to resist repetitive impacts.

scholarly journals Hidden Capital as an Alternative Method for Increasing Punching Shear Resistance of LWAC Flat Slabs

2019 ◽  
Vol 65 (4) ◽  
pp. 309-328
Author(s):  
M. Gołdyn ◽  
T. Urban
Keyword(s):  
Experimental Studies ◽  
Lightweight Aggregate ◽  
Shear Resistance ◽  
Punching Shear ◽  
Lightweight Aggregate Concrete ◽  
Control Element ◽  
Aggregate Concrete ◽  
Steel Fibres ◽  
Flat Slabs ◽  
Alternative Method

AbstractIn the paper an alternative method for increasing punching shear resistance of the flat slabs from lightweight aggregate concrete by means of hidden steel fibre reinforced capital was presented. Previous experimental studies demonstrated that the addition of steel fibres to concrete allows for increase in the punching shear resistance of flat slab. Steel fibres modify the tensile strength of concrete, which translates into increased ductility of the material. The results of the experimental investigations were presented, the aim of which was to assess the effectiveness of the proposed solution. For economic and technological reasons, a hidden capital of a height equal to half of the slabs depth was made so that the top reinforcement could be installed later. It was found that presented solution allowed to increase the load carrying capacity by about 36% with respect to the control element, made entirely of lightweight aggregate concrete.

A systematic methodology for design of retrofit actions with longevity

2018 ◽  
Vol 42 (4) ◽  
pp. 585-604 ◽  
Author(s):  
Martin Morelli ◽  
Michael A. Lacasse
Keyword(s):  
Failure Mode ◽  
Failure Modes ◽  
Energy Savings ◽  
Solid Wall ◽  
Lightweight Aggregate ◽  
Lightweight Aggregate Concrete ◽  
Maintenance Planning ◽  
Limit States ◽  
Mode Identification ◽  
Durability Assessment

This article presents a method for the design of retrofit actions with focus on energy savings that permits a systematic and thorough assessment of potential failures, anticipated maintenance and the expected durability of the retrofit actions. The proposed method combines the use of failure mode and effect analysis (FMEA) to permit identifying likely failure modes from which maintenance actions could be planned and the limit states (LS) method to assess the durability of the given retrofit action. One case study was completed to illustrate the application of: (1) the FMEA and LS method and (2) the proposed method for a retrofit action of an internal insulated solid wall of masonry bonded with lightweight aggregate concrete and floor division of concrete. It was evident that FMEA is useful regarding failure-mode identification and maintenance planning, and the LS method has its strength in durability assessment. Combining the use of both the FMEA and LS methods allowed improved design of new energy-saving retrofit actions, given that a thorough risk assessment was possible that included a decision-making process on maintenance planning, durability assessment and decision on potential redesign of retrofit actions.

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