experimental study of high strength concrete filled circular steel columns

... Behavior of High Strength Steel at Elevated Temperatures 30 3.1 Overview 30 3.2 Chemical Compositions of High Strength Steel 30 3.3 Microstructure of High Strength Steel at High ... resistance of high strength tubular steel columns infilled with ultra -high strength concrete with compressive strength up to 160MPa Although research work has been done on concrete filled steel tubular ... temperature of the steel was exceeded 2.6 Fire Resistance of Concrete Filled Steel Tubular Columns 2.6.1 Experimental Studies The experimental investigations on the fire resistance of concrete filled steel...

Ngày tải lên: 08/09/2015, 18:17

... testing effort 1.3—Definition of high- strength concrete Since the definition of high- strength concrete has changed over the years, the Committee defined a range of concrete strengths for its activities, ... coefficient of variation than normalstrength concrete, not because of the strength level, but because a higher degree of control is maintained in the production and testing of high- strength concrete ... CONTROL AND TESTING OF HIGH- STRENGTH CONCRETE Fig 4.5.4—Effect of spherically-seated platen on measured compressive strength of 150 mm (6 in.) cylinders as a function of concrete strength (adapted...

Ngày tải lên: 24/10/2014, 21:59

... Although a high- strength concrete is more brittle than a normalstrength concrete, its higher compressive strength, which leads to a larger balanced steel area, does allow a higher flexural strength ductility ... depth of compression reinforcement depth of neutral axis Young’s modulus of steel reinforcement in situ uniaxial compressive strength of concrete yield strengths of compression and tension steel ... analysis of post-peak flexural behavior of normal- and highstrength concrete beams Structural Design of Tall and Spec Buildings 12: 1–17 Kwan AKH, Ho JCM, Pam HJ 2003 Effects of concrete grade and steel...

Ngày tải lên: 17/06/2016, 14:09

... Compression steel force Fst Tension steel force f 'c Uniaxial compressive strength of concrete f co Reference strength of 10 MPa f cd Design strength of concrete f cm Mean strength of concrete f ... reduced at higher concrete strength This could be explained by an increase in concrete brittleness in the case of higher strength concrete Moreover, in the study on the effects of strain rate of impact ... conventional reinforced concrete panels, steel fibre reinforced concrete panels, profiled steel sheeting reinforced concrete panels, steel- air -steel sandwich panels and steel -concrete- steel sandwich panels...

Ngày tải lên: 09/09/2015, 08:15

... Advantages of High- Strength Concrete in Columns, ” Concrete International, April 1989 11 Colaco, J P., “75-Story Texas Commerce Plaza, Houston—The Use of High- Strength Concrete, ” High- Strength Concrete, ... reinforcing steel =concrete compressive strength =yield strength of non-prestressed steel =yield strength of hoops =yield strength of transverse reinforcing steel =axial load =pure axial load capacity of ... J.; Otani, S.; and Aoyama, H., Experimental Study of Flexural Behavior of Reinforced Concrete Columns Using High- Strength Concrete, ” Transactions of the Japan Concrete Institute, Vol 12, 1990,...

Ngày tải lên: 24/10/2014, 17:26

... Observation of decreasing dielectric constant after spraying stopped 4.2 Dielectric constant of rime ice 4.2.1 Case study To study the dielectric properties of rime ice, we conducted this study at ... coming out of the nozzle In this case study of rime ice generation was increased linearly with the spraying of water content Thickness of the ice averaged from values was 2.8cm Plots of dielectric ... constant k’ at the time of spraying liquid water; (c) Observation of decreasing dielectric constant after spraying stopped 4.1.2 Case study For this study the measured temperatures of cold room at top,...

Ngày tải lên: 05/09/2013, 15:28

... respectively He is a professor of School of Energy and Environment, Hebei University of Technology Since from 2005, he has taken as the dean of School of Energy and Environment of HBUT His work focus ... for the optimal design of similar TEDs Experimental system and procedure 2.1 Experimental setup Figure shows the experimental setup of a small-scale TED It mainly consisted of a closed cabinet, ... surfaces of the cold-side fin heat exchanger (ii) There exists a peak during the variation of the COP as a function of the input power of the thermoelectric module Under the present experimental...

Ngày tải lên: 05/09/2013, 16:10

... stable with high heat of fusion, safe and non reactive and recyclable 3.2 Experimental techniques Experimental building models each of one cubic feet were constructed using special type of hollow ... (PEG E600) Strength tests were performed for ordinary bricks and the special type of hollow bricks in compression testing machine Strength of ordinary brick was 94 KN and the Strength of hollow ... inclusion of PCMs depend on the melting temperature of the PCM, the type of PCM, the percentage of PCM used inside the conventional material, the climate, design and orientation of construction of the...

Ngày tải lên: 05/09/2013, 17:03

... ber of "false" senses, obtained from dictionary entries for words of the same part of speech The average number of "correct" senses of the words in the sample was 5.6, approximately the degree of ... three senses of the word Although frequency of use was not a criterion of selection, it was afterwards found that all of the 140 words selected appear in The Teacher's Word-Book of 30,000 Words.2 ... effect to that of the entire sentence The same procedure was used to appraise the effect of clarity on reduction of ambiguity The sample was evenly divided into words of relatively high and low...

Ngày tải lên: 16/03/2014, 19:20

... mean ARD of -0.76%, while those with high visual-observation requirements had a mean ARD of 8.53% Discussion The purpose of the present study was to compare the dualtasking ability of young and ... costs of all task combinations in our present and previous study Mean dual-task costs of all task combinations in our present and previous study [31] Each bar represents the average score of younger ... this study, which was pre-approved by the author's Ethics committee Experiment A was designed to find out whether the use of a treadmill was essential for the emergence of ARD in our previous study...

Ngày tải lên: 19/06/2014, 08:20

... form of machinability comparison  ‘Homogeneity of material’ , refers to a uniformity of its microstructure and having isotropic properties used This latter problem of lack of homogeneity of the ... way of a ‘Design of Experiments’ (DoE), in combination with ‘Value Analysis’ (VA) approach to the production problem This strategic technique to the problems of ‘machinability comparisons’ of ... resumé on just some of the machinability testing techniques favoured today 7.1.1 Design of Machinability Tests and Experimental Testing Programmes Over the years, a range of machinability testpieces...

Ngày tải lên: 21/06/2014, 22:20

... ANOVA: Total Sum of Squares about the mean: n ¯ � (y  − y ) i= ↓ Sum of squares – due to Source1 ↓ Sum of squares – due to Source2 ↓ Sum of squares – due to Source3 ↓ Sum of squares – due ... or residual Sum of Squares The technique of analysis of variance decomposes this total ‘sum of squares’ into the parts shown above, for a case in which four identifiable sources of variation are ... ‘Deployment of quality through deployment of quality functions’ (Akao, 1988) It is often known as the ‘House of Quality’ , because the tabulated graphical representation looks similar to that of a house...

Ngày tải lên: 21/06/2014, 22:20

... way: ‘The ratio of the magnitude of the output of a system with respect to that of the input – the conditions of operation and measurements must be specified’ (Smith, 1993, et al.) of increasing ... result from a range of multifarious and often linked-factors, they include: • Depth of cut (DOC) – can be considered as the principal cause and, for the prospective control of chatter The DOC ... until the commencement of chatter, then‘backing-off ’ at this level The prediction of chatter’s onset can be found analytically, this value being based upon thorough knowledge of material stiffness...

Ngày tải lên: 21/06/2014, 22:20

... of the true nature of the actual surface condition If this machined workpiece was to be used in a critical and highly-stressed in-service environment, then the user would have a false sense of ... measurement 50 ‘Sampling length’ , is often termed ‘Meter cut-off ’ , or simply the ‘cut-off ’ length and its units are millimetres The most common cut-offs are: 0.25, 0.8, 2.5, 8.0, 25.0 mm ... arithmetic mean of the absolute departures of the roughness profile from the mean line’ (i.e see Fig 163b and c) It can be expressed as follows: lr Ra = �lr � � z(x) � dx  (units of m) NB  The...

Ngày tải lên: 21/06/2014, 22:20

... the profile from the highest peak down Hence, peaks and valleys have accordingly different weights One of the problems that has arisen from utilising this technique for a topographical profile, ... quantities and it is a measure of the extent of this affiliation, thus producing its ‘correlation coefficient’ which can then be utilised *For example, having a sample of pairs of observations ‘x’ and ... region of the tool (i.e insert) only the conduction term remains ∴ Rate of heat generation (˙ ) = σ ε q ˙ Where: ‘σ’ was obtained from an emprical function of: ‘ε’ , ‘˙’; plus ‘T’ ε NB  This rate of...

Ngày tải lên: 21/06/2014, 22:20

... strength of 1400 N mm–2), Endurance limit = 700 N mm–2 (i.e above a tensile strength of 1400 N mm–2) For Cast steel/ iron: Endurance limit = 0.45 tensile strength (i.e up to tensile strength of 600 ... Most steels have an ‘endurance limit’ being about half its tensile strength, with an approximation often utilised: For steels: Endurance limit = 0.5 tensile strength (i.e up to a tensile strength ... rather than being the result of wear It can be considered as a form of fatigue failure, because of the cycles of loading and unloading during cutting, leading to particles of tool material being removed...

Ngày tải lên: 21/06/2014, 22:20

... 177e, this now being a ‘composite’ of the sum of the: machine/labour/overhead costs (Cm); with tooling cost (CT) The zenith of this curve (Fig 177e), represents the highest production rate (Prmax) ... sensitivity of 1% of its mean designed force, Such a dynamometer requires a natural frequency of at least times the ‘forcing frequency’ , The strain-gauged circuit elements should produce the minimum of ... realistic time period75 The design of most of today’s multi-component dynamometers use piezoelectric elements which are quintessentially comprised of a stack of quartz discs, or plates with accompanying...

Ngày tải lên: 21/06/2014, 22:20

... minute portion of the apparent real of contact (‘Aa’) – even after the contacting asperities of the softer material has plastically deformed (i.e yielded) Thus: Ar = Fn /σy (i) 78 ‘Law(s) of friction’ , ... loading, the top of these asperities will yeild, creating a real area of contact until such a time, that they are capable of supporting an applied load In the main, for the vast majority of engineering ... (1935, ’37 and ’43), where the shear strength when experimental machining of polycrystalline metals was shown to be dependent on the normal stress on the ‘plane of shear’ Now from Fig 181, we can...

Ngày tải lên: 21/06/2014, 22:20

... Static strength – is affected by the yeild point of the workpiece material, which in turn, is influenced by the presence of residual stresses, • Dynamic strength – of the part in-service can often ... some form of harmonic effects present: departures-from-roundness characteristics (i.e a combination of harmonic influences present) The exposed sterile surface (Fig 185), is the result of highly ... that an improvement of metallographical inspection of a sectioned machined surface can be made without unduly affecting any form of surface distortion, ‘tapersectioning’ has often been utilised...

Ngày tải lên: 21/06/2014, 22:20

... By way of comparison of this untempered martensitic ‘whitelayer’ phase, a conventional high- speed steel (HSS) milling cutter’s teeth would have had a maximum hardness after heattreatment of 62 ... 1998 Fick, A.E [Laws of Diffusion], Annals of Physics (Leipzig, Germany), Vol 170, 59, 1855 Field, M and Kahles, J.F Review of Surface Integrity of Machined Components Annals of the CIRP, Vol 20(2), ... dislocations reduce the strength of the material, as less force is necessary to alter the atomic lattice Dislocation motion of atoms is a complex subject, which goes beyond the scope of the present text,...

Ngày tải lên: 21/06/2014, 22:20