BEHAVIOR OF FULLY ENCASED COLD FORMED STEEL JOISTS WITH/WITHOUT WEB OPENINGS: EXPERIMENTAL INVESTIGATION

2018 ◽  
Vol 5 (1) ◽  
Author(s):  
Hanadi Elkhansa ◽  
Adnan Masri ◽  
Zaher Abou Saleh
Keyword(s):  
Experimental Investigation ◽  
Energy Absorption ◽  
Failure Modes ◽  
Load Capacity ◽  
Composite Beams ◽  
Absorption Capacity ◽  
Cross Sectional ◽  
Web Openings ◽  
Flexural Failure ◽  
Cold Formed Steel

This paper presents an experimental investigation on the behavior of encased light cold-formed steel joists with/without web openings. The study is carried on two sets of composite beams constructed of cold-formed steel joists using I-beam built-up sections. The first set has no web openings while the second set has circular web openings. Each set consists of three beams with various steel section-concrete reinforcing ratio. The constant parameters included in this study are the cross sectional area of the specimen, distribution of web openings in the encased steel I-joist, and the compressive strength of concrete. The tests have been conducted by applying two concentrated identical loads. Consequently, a comparative study is carried out to compare between the behavior of specimens within one set, and a comparison between the specimens of the two sets. This comparison is related to strength, stiffness, ductility, energy absorption capacity and failure modes. Based on the testing results, it is concluded that, the load capacity of the composite beams without web openings is greater than that with web openings for the same steel ratio. But the existence of web openings in the encased steel joists enhances the ductility and the energy absorption of the composite beams. Also using cold formed steel I-joists in the composite beams allow the failure mode to be ductile flexural failure.

scholarly journals Buckling behavior of cold-formed steel columns at both ambient temperature and simulated fire conditions

Fire Research ◽  
2016 ◽  
Author(s):  
Hélder D. Craveiro ◽  
João Paulo C. Rodrigues ◽  
Luís M. Laím
Keyword(s):  
Experimental Investigation ◽  
Ambient Temperature ◽  
Cross Sections ◽  
Failure Modes ◽  
Steel Columns ◽  
Buckling Behavior ◽  
Wide Range ◽  
Cold Formed Steel ◽  
Simulated Fire ◽  
Fire Conditions

Cold-formed steel (CFS) profiles with a wide range of cross-section shapes are commonly used in building construction industry. Nowadays several cross-sections can be built using the available standard single sections (C, U, Σ, etc.), namely open built-up and closed built-up cross-sections. This paper reports an extensive experimental investigation on the behavior of single and built-up cold-formed steel columns at both ambient and simulated fire conditions considering the effect of restraint to thermal elongation. The buckling behavior, ultimate loads and failure modes, of different types of CFS columns at both ambient and simulated fire conditions with restraint to thermal elongation, are presented and compared. Regarding the buckling tests at ambient temperature it was observed that the use of built-up cross-sections ensures significantly higher values of buckling loads. Especially for the built-up cross-sections the failure modes were characterized by the interaction of individual buckling modes, namely flexural about the minor axis, distortional and local buckling. Regarding the fire tests, it is clear that the same levels of restraint used in the experimental investigation induce different rates in the generated restraining forces due to thermal elongation of the columns. Another conclusion that can be drawn from the results is that by increasing the level of restraint to thermal elongation the failure of the columns is controlled by the generated restraining forces, whereas for lower levels of restraint the temperature plays a more important role. Hence, higher levels of imposed restraint to thermal elongation will lead to higher values of generated restraining forces and eventually to lower values of critical temperature and time.

Experimental Investigation of Energy Absorption of ‎Partially Wrapped Thin-Walled ‎Aluminium-Glass/Epoxy Tube Subjected to Quasi-Static Loading

2017 ◽  
Vol 904 ◽  
pp. 61-67
Author(s):  
Tahir Abbas ◽  
Hamdan H. Ya ◽  
Mohamad Zaki Abdullah
Keyword(s):  
Experimental Investigation ◽  
Energy Absorption ◽  
Fiber Orientation ◽  
Static Loading ◽  
Failure Modes ◽  
Testing Machine ◽  
Filament Winding ◽  
Universal Testing ◽  
Thin Walled ◽  
Filament Winding Process

This paper describes the failure modes and energy absorption capability of partially wrapped aluminium-glass/epoxy tubes, subjected to quasi-static loading. ‎These tubes are used in aircraft and automobiles applications. Aluminium tubes were partially wrapped with 4, 6 and 8 glass/epoxy layers, using filament winding process. The 90◦ fiber orientation was used for glass/epoxy layers. Quasi-static loading of partially wrapped tubes was carried out at 5mm/min speed, using the universal ‎testing machine. The experimental results revealed that partially wrapped aluminium tubes are 42.54%, 47.77% and 28.91% more ‎efficient in energy absorption as compared to the simple aluminium tubes. Furthermore, the effect of glass/epoxy layers on ‎failure modes has also been described.

Reinforcement Schemes for Cold-Formed Steel Joists with a Large Web Opening in Flexural Zone - An Experimental Investigation

2021 ◽  
Author(s):  
Sandesh Raj Acharya ◽  
Ken S Sivakumaran
Keyword(s):  
Experimental Investigation ◽  
Flexural Strength ◽  
North American ◽  
Web Openings ◽  
Reinforcement Scheme ◽  
Web Opening ◽  
Cold Formed Steel

The objective of this investigation is to develop an economical and an efficient reinforcement scheme for large web openings in cold-formed steel (CFS) joists in flexural zones that would restore the original moment resistance of the section. This investigation considered commonly used floor joists in North American CFS construction. Tests on joists webs with no openings and with large circular and square openings located at the mid-depth revealed that large openings may reduce the flexural strength by 23%. A reinforcement scheme consisting of screw fastening of 31.75 mm x 12.7 mm (1-1/2”x1/2”) bridging channels having matching thickness as of the receiving joist, along the compression and the tensile edges of the opening utilizing a screw spacing of 31.75 mm was established. Three identical tests utilizing the proposed reinforcement scheme restored the corresponding flexural strengths of the CFS section under consideration, and the failure locations were outside the reinforced opening regions.

Cushioning energy absorption of paper corrugation tubes with regular polygonal cross-section under axial static compression

2021 ◽  
Vol 28 (1) ◽  
pp. 24-38
Author(s):  
Jianfen Kang ◽  
Yanfeng Guo ◽  
Yungang Fu ◽  
Qiong Li ◽  
Yabo Lv
Keyword(s):  
Energy Absorption ◽  
Cross Section ◽  
Failure Modes ◽  
Unit Area ◽  
Deformation Mode ◽  
Tube Length ◽  
Cross Sectional ◽  
Static Compression ◽  
Regular Triangle ◽  
Sectional Shape

Abstract The paper corrugation tube is an innovative kind of energy absorbing structure and shock absorber which can play an important role on the cushioning energy absorption for airdrop equipments and transportation packaging. The deformation characteristics and failure modes of the regular triangle, quadrangle, pentagon and hexagon paper corrugation tubes were comparatively studied by a series of axial static compression experiments, the cushioning energy absorption was evaluated by the seven characteristic parameters (e.g. initial peak force, mean crush force, total energy absorption, specific energy absorption, crush force efficiency, unit area energy absorption and stroke efficiency), and the influences of tube direction, cross-sectional shape, tube length and compression rate on failure modes and cushioning energy absorption were analyzed and compared. These researches showed that the tubes along X direction only have the accordion deformation mode, yet the tubes along Y direction have four deformation modes including steady state progressive buckling, Euler buckling, angular tear and transverse shear. For the paper corrugation tubes along Y direction, the cross-sectional shape has obvious influence on the cushioning energy absorption of structures, and the specific energy absorption and unit area energy absorption of regular triangle and pentagon tubes are better than those of the tubes with regular quadrilateral and hexagonal cross-section at compression rates of 12 and 48mm/min. The tube length of 150 mm or compression rate of 72 mm/min would cause the increase of contribution proportion of non-ideal deformation mode and the decrease of cushioning properties. The paper corrugation tubes along X direction have more stable and controllable deformation mode, yet the paper corrugation tubes along Y direction have better cushioning energy absorption.

scholarly journals Shear And Flexural Behaviour Of Fiber Reinforced Lightweight Self-Consolidating Concrete Beams

2021 ◽  
Author(s):  
Ali Rashidian ◽  
Khandaker M. Anwar
Keyword(s):  
Energy Absorption ◽  
Failure Modes ◽  
Crumb Rubber ◽  
Absorption Capacity ◽  
Fiber Reinforced ◽  
Flexural Behaviour ◽  
Energy Absorption Capacity ◽  
Self Consolidating Concrete ◽  
Poly Ethylene ◽  
Energy Absorbing

This research studied the shear and flexural behaviour of fiber reinforced lightweight self-consolidating concrete (FRLWSCC) beams made of three different fibers such as: High-Density Poly Ethylene (HDPE), Crumb Rubber (CR) and Polyvinyl Alcohol (PVA) compared with lightweight self-consolidating concrete (LWSCC) beams. The performances of all beams were described based on load-deformation or moment-rotation response, strain developments, crack characterization, failure modes, ductility, stiffness and energy absorbing capacity. All FRLWSCC shear beams showed higher ultimate shear resistance, ductility and energy absorption capacity compared to LWSCC beams. All FRLWSCC flexural beams at failure exhibited higher flexural capacity, more cracks with smaller width, higher ductility, higher energy absorption capacity and lower stiffness compared to their LWSCC counterparts. FRLWSCC beams especially made of HDPE fibers showed better shear and flexural capacities besides satisfactory ductility performance. Experimental shear and flexural capacities of FRLWSCC beams were compared with those predicted from Code based and other existing equations.

scholarly journals Axial Strength Of Lightweight Self-Consolidating Concrete Columns With Engineered Cementitious Composite

2021 ◽  
Author(s):  
Sandeep Parajuli
Keyword(s):  
Axial Load ◽  
Failure Modes ◽  
Load Capacity ◽  
Absorption Capacity ◽  
Normal Weight ◽  
Cementitious Composite ◽  
Concrete Core ◽  
Self Consolidating Concrete ◽  
Engineered Cementitious Composite ◽  
Axial Strength

Axial load behavior of confined columns with engineered cementitious composite (ECC) wrapping was investigated through experimental, analytical and finite element (FE) investigations. The variables in the study were: geometry (cylindrical and rectangular), presence or absence of longitudinal and tie reinforcement, ECC wrap thickness, types of concrete core (lightweight and normal weight self-consolidating concrete) and type of loading (applied through both core and wrap or core only). The effect of these variables on axial load-deformation response, strain characteristics, failure modes, ductility, energy absorption capacity and axial strength were evaluated. The confined concrete strengths predicted from existing analytical and developed FE models were found to be in good agreement with those of experiments. The axial load capacity and ductility were increased for columns with highest ECC wrap thickness (50 mm) while thinner wrap increased stiffness instead of ductility. Canadian code conservatively predicted axial strength of columns having increased thickness of ECC wrap.

A Performance Study of Clinched Joints with Different Material

2014 ◽  
Vol 887-888 ◽  
pp. 1265-1268
Author(s):  
Fu Long Liu ◽  
Xiao Cong He ◽  
Lun Zhao
Keyword(s):  
Energy Absorption ◽  
High Speed ◽  
Failure Modes ◽  
Sheet Material ◽  
Alloy Sheet ◽  
Absorption Capacity ◽  
Shear Loading ◽  
Performance Study ◽  
Energy Absorption Capacity ◽  
Mechanical Fastening

Clinching is a high-speed mechanical fastening technique for point joining of sheet material. In order to investigate the influence of material property on the mechanical property and failure mode of clinched joints, three types of clinched joints in aluminum alloy sheet were tested under tension-shear loading with MTS landmark, separately. Results showed that the property of the substrate had effective on the performance of clinched joints. Clinched joints had higher strength and good energy absorption capacity when the strength of the substrate was higher. The strength and energy absorption capacity of the clinched joints were evaluated via load-displacement curves. While the failure modes of clinched joints were all the same: neck facture failure.

Application and Prospect of Bamboo/Steel Composite Material in Civil Engineering Structure

2010 ◽  
Vol 113-116 ◽  
pp. 989-993 ◽  
Author(s):  
Huang Ying Shen ◽  
Yu Shun Li ◽  
Zhen Wen Zhang ◽  
Tian Yuan Jiang ◽  
Jun Zhe Liu
Keyword(s):  
Composite Material ◽  
Failure Modes ◽  
Civil Engineering ◽  
Failure Process ◽  
Composite Beams ◽  
Flexural Behavior ◽  
Material System ◽  
Composite Slabs ◽  
Steel Composite ◽  
Cold Formed Steel

The objective of this research was to develop a new composite material/system in structural civil engineering. To use of mechanical properties of bamboo-based panel and cold-formed steel, this study composite two kind of materials above-mentioned together utilizing structural adhesives. The research developed various of bamboo/steel composite members, such as composite slabs, composite walls, composite beams and composite columns. And the paper emphasized mechanical performance of bamboo/steel composite slabs and composite beams. Experimental studies on flexural behavior of 6 composite slabs and 9 composite beams were carried out and the failure process, failure modes and failure mechanism were investigated. Experiment results indicates that the bamboo plywood and cold-formed steel can form an excellent composite cross-section; Load vs. mid-span deflection curves of composite slabs and composite beams show linear on serviceability limit state. The maximum ultimate strength of composite slabs and beams have reached 30.0 kN•m and 36.13 kN•m respectively. The study shows that bamboo-steel composite members have good prospects in building structures of China.

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