Strength and Stiffness of Lightweight Concrete Corners

10.14359/7168 ◽  
1972 ◽  
Vol 69 (7) ◽  
Keyword(s):  
Lightweight Concrete ◽  
Strength And Stiffness

scholarly journals Push-out Tests for Determining Shear Strength and Stiffness of Perfobond Connector-Experimental Study

2019 ◽  
Vol 12 (4) ◽  
pp. 225-231
Author(s):  
Khawla A. Farhan ◽  
Muhaned A. Shallal
Keyword(s):  
Compressive Strength ◽  
Shear Strength ◽  
Lightweight Concrete ◽  
Steel Tube ◽  
Ultimate Shear Strength ◽  
Concrete Blocks ◽  
Strength And Stiffness ◽  
Square Steel Tube ◽  
Concrete Filled Steel Tubes ◽  
Push Out

This study presents an experimental investigation for push-out tests in order to evaluate the performance of continuous perfobond connectors. A total of five specimens composed of light-weight concrete-filled steel tubes (square and circle sections) with two reinforced blocks were tested. The measured parameters are the compressive strength of the concrete blocks and the type of the section. The specimens were tested under a concentric load applied on the steel tube filled with lightweight concrete; the corresponding slip value was measured   using two LVDTs. The experimental results showed that the ultimate shear strength and stiffness of the square steel tube filled with concrete were higher than that of circular samples. The ultimate shear strength and stiffness increased with an increase of concrete compressive strength, while the corresponding slips    showed decreasing in their values with increase of the compressive strength of the concrete.

scholarly journals Steel Concrete Composite Systems for Modular Construction of High-rise Buildings

2018 ◽  
Author(s):  
Richard JY Liew ◽  
Z. Dai ◽  
Yie Sue Chau
Keyword(s):  
Structural Integrity ◽  
Lightweight Concrete ◽  
Work Force ◽  
Innovative Technology ◽  
Modular Construction ◽  
High Rise ◽  
Modular Units ◽  
Speed Up ◽  
Strength And Stiffness ◽  
Tolerance Control

Modular construction has gained popularity and attention particularly in low-rise building lately due to its numerous advantages: faster construction speed, better quality control, reduction in work force and construction waste, etc. This innovative technology promotes off-site manufacturing of modular units and on-site assembly, improving the construction efficiency and productivity. However, modular construction is not commonly used in high-rise buildings because of the joints’ flexibility as well as manufacturing and construction tolerance, which have significant impact on the overall stability of the building. This paper highlights the existing challenges of modular construction of high-rise buildings and provide several options to address these challenges. Firstly, the weight of a module is constrained by the transportation and lifting crane capacities. For this reason, lightweight concrete is introduced together with structural steel section to form lightweight steel-concrete composite system to reduce the weight of the module without compromising the strength and stiffness. Secondly, to speed up the site assembly of modular units, special joints are developed to resist the forces due to gravity and horizontal loads. Fast and easy joining techniques with acceptable tolerance control are essential to ensure the structural integrity and stability of the building. Finally, the innovation for productivity can be maximized by implementing automation technologies in the manufacturing and construction of the modular units.

Experimental Study on Prefabricated Lightweight Composite Wall Panels under Flexural Loading

2020 ◽  
Vol 9 (4) ◽  
pp. 215-225
Author(s):  
Md Kamrul Hassan ◽  
Karanraj Singh ◽  
Rohit Kumar
Keyword(s):  
Experimental Study ◽  
Flexural Strength ◽  
Lightweight Concrete ◽  
Flexural Loading ◽  
Three Samples ◽  
Wall Panels ◽  
Composite Wall ◽  
Strength And Stiffness ◽  
The Moment ◽  
Steel Stud

 The prefabricated lightweight wall panels have been widely used instead of brick walls in the modern construction industry of building due to its many advantages. As lightweight concrete is week under flexural loading, more reinforcement bars are required to improve the flexural strength of conventional lightweight wall panel. In this paper, steel studs/angles are proposed instead of reinforcement bars because the moment of inertial of steel stud/angle is higher than reinforcement bars. Experimental study has been conducted to investigate the flexural behaviour of proposed prefabricated lightweight composite (PLC) wall panels. Three samples of PLC wall panels are fabricated using lightweight concrete materials and studs. The parameters that are changed in the test specimens are material types (cold-form steel or carbon steel) and numbers of steel studs/angles. The test results show that the material types and numbers of steel studs/angles has significant impact on the flexural strength and stiffness of PLC wall panels.

Microstructural characterization of plasma-processed Ti-Al metal matrix composites

1989 ◽  
Vol 47 ◽  
pp. 552-553
Author(s):  
M. G. Burke ◽  
M. N. Gungor ◽  
M. A. Burke
Keyword(s):  
High Temperature ◽  
Titanium Aluminide ◽  
Plasma Processing ◽  
Microstructural Characterization ◽  
High Temperature Strength ◽  
Matrix Composites ◽  
Intermetallic Matrix ◽  
Long Time ◽  
Strength And Stiffness ◽  
Intermetallic Matrix Composites

Intermetallic matrix composites are candidates for ultrahigh temperature service when light weight and high temperature strength and stiffness are required. Recent efforts to produce intermetallic matrix composites have focused on the titanium aluminide (TiAl) system with various ceramic reinforcements. In order to optimize the composition and processing of these composites it is necessary to evaluate the range of structures that can be produced in these materials and to identify the characteristics of the optimum structures. Normally, TiAl materials are difficult to process and, thus, examination of a suitable range of structures would not be feasible. However, plasma processing offers a novel method for producing composites from difficult to process component materials. By melting one or more of the component materials in a plasma and controlling deposition onto a cooled substrate, a range of structures can be produced and the method is highly suited to examining experimental composite systems. Moreover, because plasma processing involves rapid melting and very rapid cooling can be induced in the deposited composite, it is expected that processing method can avoid some of the problems, such as interfacial degradation, that are associated with the relatively long time, high temperature exposures that are induced by conventional processing methods.

Factors affecting microstructural scale in liquid crystalline polymers

1990 ◽  
Vol 48 (4) ◽  
pp. 220-221
Author(s):  
Christine M. Dannels ◽  
Christopher Viney
Keyword(s):  
Liquid Crystalline ◽  
Liquid Crystalline Polymers ◽  
Factors Affecting ◽  
Crystalline Polymers ◽  
Thermal Expansion Coefficients ◽  
Low Thermal Expansion ◽  
Lower Viscosity ◽  
Fine Microstructure ◽  
Planar Orientation ◽  
Strength And Stiffness

Processing polymers from the liquid crystalline state offers several advantages compared to processing from conventional fluids. These include: better axial strength and stiffness in fibers, better planar orientation in films, lower viscosity during processing, low solidification shrinkage of injection moldings (thermotropic processing), and low thermal expansion coefficients. However, the compressive strength of the solid is disappointing. Previous efforts to improve this property have focussed on synthesizing stiffer molecules. The effect of microstructural scale has been overlooked, even though its relevance to the mechanical and physical properties of more traditional materials is well established. By analogy with the behavior of metals and ceramics, one would expect a fine microstructure (i..e. a high density of orientational defects) to be desirable.Also, because much microstructural detail in liquid crystalline polymers occurs on a scale close to the wavelength of light, light is scattered on passing through these materials.

Observing the relaxation of molecular orientation in sheared liquid crystalline polymer solutions

1990 ◽  
Vol 48 (4) ◽  
pp. 1092-1093
Author(s):  
Wendy Putnam ◽  
Christopher Viney
Keyword(s):  
Molecular Orientation ◽  
Liquid Crystalline Polymer ◽  
Liquid Crystalline ◽  
Crystalline Polymer ◽  
Polymer Processing ◽  
Molecular Alignment ◽  
Global Alignment ◽  
Shear Direction ◽  
Axial Strength ◽  
Strength And Stiffness

Liquid crystalline polymers (solutions or melts) can be spun into fibers and films that have a higher axial strength and stiffness than conventionally processed polymers. These superior properties are due to the spontaneous molecular extension and alignment that is characteristic of liquid crystalline phases. Much of the effort in processing conventional polymers goes into extending and aligning the chains, while, in liquid crystalline polymer processing, the primary microstructural rearrangement involves converting local molecular alignment into global molecular alignment. Unfortunately, the global alignment introduced by processing relaxes quickly upon cessation of shear, and the molecular orientation develops a periodic misalignment relative to the shear direction. The axial strength and stiffness are reduced by this relaxation.Clearly there is a need to solidify the liquid crystalline state (i.e. remove heat or solvent) before significant relaxation occurs. Several researchers have observed this relaxation, mainly in solutions of hydroxypropyl cellulose (HPC) because they are lyotropic under ambient conditions.

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