Behavior of Non-Shear-Strengthened UHPC Beams under Flexural Loading: Influence of Reinforcement Percentage

2021 ◽  
Vol 11 (23) ◽  
pp. 11346
Author(s):  
Mohammad Iqbal Khan ◽  
Galal Fares ◽  
Yassir M. Abbas ◽  
Fahad K. Alqahtani
Keyword(s):  
Crack Opening ◽  
Shear Cracks ◽  
Initial Stiffness ◽  
Moment Capacity ◽  
Reinforced Beams ◽  
Before And After ◽  
Cause Of Failure ◽  
Compressive And Flexural Strengths ◽  
The Moment ◽  
Cracking Pattern

In the present work, the structural responses of 12 UHPC beams to four-point loading conditions were experimentally and analytically studied. The inclusion of a fibrous system in the UHPC material increased its compressive and flexural strengths by 31.5% and 237.8%, respectively. Improved safety could be obtained by optimizing the tensile reinforcement ratio (ρ) for a UHPC beam. The slope of the moment–curvature before and after steel yielding was almost typical for all beams due to the inclusion of a hybrid fibrous system in the UHPC. Moreover, we concluded that as ρ increases, the deflection ductility exponentially increases. The cracking response of the UHPC beams demonstrated that increasing ρ notably decreases the crack opening width of the UHPC beams at the same service loading. The cracking pattern the beams showed that increasing the bar reinforcement percentages notably enhanced their initial stiffness and deformability. Moreover, the flexural cracks were the main cause of failure for all beams; however, flexure shear cracks were observed in moderately reinforced beams. The prediction efficiency of the proposed analytical model was established by performing a comparative study on the experimental and analytical ultimate moment capacity of the UHPC beams. For all beams, the percentage of the mean calculated moment capacity to the experimentally observed capacity approached 100%.

scholarly journals Feasibility of Using Palmyrah Strips as Reinforcing Material in Cost Effective Houses

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
K. Baskaran ◽  
H. E. Mallikarachchi ◽  
M. J. P. L. M. Jayasekara ◽  
G. A. T. Madushanka
Keyword(s):  
Building Materials ◽  
Residential Buildings ◽  
Cost Effective ◽  
Capital Investments ◽  
Economic Resource ◽  
Moment Capacity ◽  
Reinforced Beams ◽  
Failure Loads ◽  
Predicted Values ◽  
The Moment

Construction of cost effective houses is a dilemma among the impoverished population in developing countries. The ever increasing price of traditional building materials results in high capital investments for residential buildings. Palmyrah is a significant economic resource, widely spread all over the northeast region of Sri Lanka. This research explores the technical feasibility of using heartwood of Palmyrah as a reinforcing member in lightly loaded concrete elements. Initially, mechanical properties of Palmyrah were examined through static bending, tensile, and compressive tests. Percentages of water absorption, dimensional stability, and anchorage bond strength were investigated to envisage the suitability of Palmyrah as reinforcement. Next, several short span slabs and beams reinforced with Palmyrah strips were subjected to tests. It was observed that Palmyrah reinforcement enhanced the moment capacity of the slabs and beams compared to unreinforced sections. Experimental failure loads of slabs and beams were higher than theoretically predicted values with Palmyrah reinforcement. Further, Palmyrah reinforced beams and slabs underwent flexural failures. Thus, it is concluded that heartwood of Palmyrah has the potential to be used as reinforcement in lightly loaded slabs and beams. Further research is recommended to investigate the durability and serviceability issues.

Flexural Resistance of Steel-Coconut Shell Concrete-Steel Composite Beam with Normal and J-Hook Shear Studs

2020 ◽  
Vol 12 (9) ◽  
Author(s):  
Lakshmi Thangasamy ◽  
◽  
Gunasekaran Kandasamy ◽  
Keyword(s):  
Concrete Strength ◽  
Steel Plates ◽  
Coconut Shell ◽  
Core Material ◽  
River Sand ◽  
Concrete Core ◽  
Conventional Concrete ◽  
Moment Capacity ◽  
The Moment ◽  
Core Concrete

Many researches on double skin sandwich having top and bottom steel plates and in between concrete core called as steel-concrete-steel (SCS) were carried out by them on this SCS type using with different materials. Yet, use of coconut shell concrete (CSC) as a core material on this SCS form construction and their results are very limited. Study investigated to use j-hook shear studs under flexure in the concept of steel-concrete-steel (SCS) in which the core concrete was CSC. To compare the results of CSC, the conventional concrete (CC) was also considered. To study the effect of quarry dust (QD) in its place of river sand (RS) was also taken. Hence four different mixes two without QD and two with QD both in CC and CSC was considered. The problem statement is to examine about partial and fully composite, moment capacity, deflection and ductility properties of CSC used SCS form of construction. Core concrete strength and the j-hook shear studs used are influences the moment carrying capacity of the SCS beams. Use of QD in its place of RS enhances the strength of concrete produced. Deflections predicted theoretically were compared with experimental results. The SCS beams showed good ductility behavior.

EVALUATION OF THE EFECTS OF ELECTRONIC ACUPUNCTURE COMBINED WITH “TAM TY THANG” REMEDY IN THE TREATMENT OF RHEUMATOID ARTHRITIS BY WIND-COLD-DAMP

2017 ◽  
pp. 122-127
Author(s):  
Thi Luu Nguyen ◽  
Thi Tan Nguyen
Keyword(s):  
Rheumatoid Arthritis ◽  
Side Effects ◽  
Prospective Study ◽  
Key Words Rheumatoid Arthritis ◽  
Good Effect ◽  
Good Level ◽  
Relieve Pain ◽  
Level Of Activity ◽  
Before And After ◽  
The Moment

Objectives: To assess the effect of electronic acupuncture combined with “Tam ty thang” remedy in the treatment of rheumatoid arthritis by wind-cold-damp. Materials and methods: prospective study, comparing before and after treatment, including 43 patients who were diagnosed with rheumatoid arthritis by wind-cold-damp according to traditional medicine. Results: good level occupied 69,8%, and fair good level occupied 30,2%.The improved motor function accounted for 95.3%, to relieve pain up to 95,3%, reducing inflammation of VSS in 1 hour at the moment No 31,65, N28 17,88. The improvement in the level of activity of the hand reached 48,8% for good level. Conclusions: The method of electronic acupuncture combined with “Tam ty thang” remedy have a good effect in the treatment of rheumatoid arthritis by wind-cold-damp and it didn’t cause significantly side effects in clinic. Key words: rheumatoid arthritis, electronic acupuncture, “Tam ty thang” remedy

Risk factors of postthrombotic syndrome before and after deep venous thrombosis treatment

2016 ◽  
Vol 32 (6) ◽  
pp. 384-389 ◽  
Author(s):  
Rob HW Strijkers ◽  
Mark AF de Wolf ◽  
Cees HA Wittens
Keyword(s):  
Risk Factors ◽  
Venous Thrombosis ◽  
Deep Venous Thrombosis ◽  
Treatment Options ◽  
Postthrombotic Syndrome ◽  
Factor X ◽  
Catheter Directed Thrombolysis ◽  
Before And After ◽  
Patient Selection Criteria ◽  
The Moment

Postthrombotic syndrome is the most common complication after deep venous thrombosis. Postthrombotic syndrome is a debilitating disease and associated with decreased quality of life and high healthcare costs. Postthrombotic syndrome is a chronic disease, and causative treatment options are limited. Prevention of postthrombotic syndrome is therefore very important. Not all patients develop postthrombotic syndrome. Risk factors have been identified to try to predict the risk of developing postthrombotic syndrome. Age, gender, and recurrent deep venous thrombosis are factors that cannot be changed. Deep venous thrombosis location and extent seem to predict severity of postthrombotic syndrome and are potentially suitable as patient selection criteria. Residual thrombosis and reflux are known to increase the incidence of postthrombotic syndrome, but are of limited use. More recently developed treatment options for deep venous thrombosis, such as new oral factor X inhibitors and catheter-directed thrombolysis, are available at the moment. Catheter-directed thrombolysis shows promising results in reducing the incidence of postthrombotic syndrome after deep venous thrombosis. The role of new oral factor X inhibitors in preventing postthrombotic syndrome is still to be determined.

scholarly journals TRANSITION TO THE SECOND GREEN REVOLUTION IN THE CONDITIONS OF ACCOUNT TO DIGITAL ECONOMY

2018 ◽  
Keyword(s):  
World War Ii ◽  
Information And Communication Technologies ◽  
Green Revolution ◽  
Animal Husbandry ◽  
Digital Economy ◽  
Digital Information ◽  
World War ◽  
Before And After ◽  
Information And Communication ◽  
The Moment

the problems of the transition to the second green revolution in the context of tak-ing into account the digital economy were considered from the state of the moment of Russian agri-culture in 1913, taking into account both the yield, harvesting and export of cereals and the number of horses and cattle before and after the First World War, after the Civil War, on the eve and after World War II. The situation of mechanization of agriculture and the transition to intensive produc-tion and supply by defense consumers with the transition to the first green revolution and the inten-sive development of animal husbandry with the Italian technology of megacomplexes of pig and poultry farming with the import of corn to feed them are considered. The balance of feed is practically not achieved due to the intensive export of cereals, mainly wheat, corn and soybeans abroad. The increase in the production of various grain crops is currently possible only due to the transition to intensification of their production, the introduction of biomineral fertilizers in the framework of the second green revolution and the consideration of the prospects of digital information and communication technologies in the development of the digital economy.

scholarly journals Flexural Behavior of Steel Beam Strengthening by Prestressing Strands

2018 ◽  
Vol 7 (4.20) ◽  
pp. 572
Author(s):  
Dr. Mohammed M. Rasheed ◽  
Mr. Ali F. Atshan ◽  
Mr. Kamal Sh. Mahmoud
Keyword(s):  
Reference Beam ◽  
Flexural Behavior ◽  
Radius Of Curvature ◽  
Steel Beams ◽  
Steel Beam ◽  
Bottom Flange ◽  
Moment Capacity ◽  
External Prestressing ◽  
Prestressing Strands ◽  
The Moment

Seven simply supported steel beams were tested to explain the effect of strengthening by external prestressing strands. All of the beams have the same steel section, clear span length and the strengthening samples which implemented by two external prestressing strands. The tested beams are divided into two categories according to existing of external prestressing strands, the first category consists of one steel beam as a reference, while, the second group deals with steel beams strengthening by external prestressing strands and consists of six steel beams divided according to the eccentricity location of prestressing strand with jacking stress (815 MPa). From experimental results, it was found that the moment curvature curves behavior for the tested beams are stiffer and with less ductility than the reference beams and the ultimate moment capacity is increased with increasing the eccentricity location. While, the maximum radius of curvature at bottom flange decreases with increasing the eccentricity location as compare with the reference beam.   

Database of rocking shallow foundation performance: Slow-cyclic and monotonic loading

2020 ◽  
Vol 36 (3) ◽  
pp. 1585-1606 ◽  
Author(s):  
Manouchehr Hakhamaneshi ◽  
Bruce L. Kutter ◽  
Andreas G. Gavras ◽  
Sivapalan Gajan ◽  
Angelos Tsatsis ◽  
...  
Keyword(s):  
Monotonic Loading ◽  
Testing Equipment ◽  
Shallow Foundation ◽  
Moment Capacity ◽  
Wide Range ◽  
Supporting Soil ◽  
Rocking Foundations ◽  
System Properties ◽  
The Moment ◽  
Cyclic Loading Tests

Many physical model tests have examined the performance of rocking foundations during cyclic and seismic loading. These tests varied in model size, testing equipment, superstructure properties, footing shape, supporting soil environment, and loading protocol. “FoRCy, Foundation Rocking database of Cyclic and Monotonic Loading” is a new database (published at https://datacenterhub.org/ ), summarizing the results of monotonic and slow-cyclic loading tests of rocking foundations. The database consists of columns identifying testing equipment and facility, soil, superstructure, and system properties, as well as loading protocol and results. The database contains 456 records (rows), each one being unique in either model configuration or loading amplitude. To illustrate its value, this article shows correlations between (1) settlement, rotation, and factor of safety with respect to bearing capacity and (2) moment and cumulative rotation for shallow footings. Data indicate that the rotation required to mobilize the moment capacity is surprisingly constant (about 0.01 radians) for a wide range of experiments.

Microvascular response to blockade of prostaglandin synthesis in rat skeletal muscle

1982 ◽  
Vol 243 (1) ◽  
pp. H51-H60 ◽  
Author(s):  
J. E. Faber ◽  
P. D. Harris ◽  
I. G. Joshua
Keyword(s):  
Skeletal Muscle ◽  
Cremaster Muscle ◽  
Local Blood Flow ◽  
Local Inhibition ◽  
Microvascular Response ◽  
Before And After ◽  
Endogenous Prostaglandins ◽  
The Moment ◽  
Arteriolar Tone ◽  
Arteriolar Diameter

The contribution of endogenous prostaglandins (PGs) to the control of arteriolar diameter in the microcirculation is incompletely defied and has only been studied in drug-anesthetized animals. To test the possibility that endogenous PGs are tonically released to exert a net dilator influence at certain levels in the microcirculation, television microscopy was used to quantitate the arteriolar responses in the rat cremaster muscle to local blockade of PG synthesis with indomethacin. Rats were decerebrated by a midcollicular transection and were allowed to recover from surgical anesthesia. The cremaster muscle with intact circulation and innervation was suspended by sutures in a temperature-controlled Krebs bath. Diameters, vasomotion frequency, and vasomotion amplitude of arterioles at several anatomic levels were measured before and after local inhibition of PG synthesis in the presence and absence of alpha-adrenergic receptor blockade. Inhibition of PG synthesis produced marked constriction (42-66% of control) at all arteriolar levels, with greater responses occurring in the smaller arterioles. PG synthesis blockade increased vasomotion frequency in arterioles that exhibited spontaneous vasomotion during control periods, and blockade induced vasomotion in vessels lacking spontaneous vasomotion. Pretreatment with phentolamine significantly attenuated the constriction and augmentation of vasomotion. These data indicate that dilator PGs participate in the moment-to-moment regulation of arteriolar tone and local blood flow in skeletal muscle. Further, their mechanism of action may involve alterations in neuronal norepinephrine release or alpha-receptor sensitivity.

Conventional and centrifuge model studies of the moment carrying capacity of short pier foundations in clay

1995 ◽  
Vol 32 (6) ◽  
pp. 976-988 ◽  
Author(s):  
G.J.W. King ◽  
M. Laman
Keyword(s):  
Carrying Capacity ◽  
Three Dimensional ◽  
Model Tests ◽  
Rotational Stability ◽  
Moment Capacity ◽  
Centrifuge Model ◽  
Model Studies ◽  
Saturated Clay ◽  
The Moment ◽  
Centrifuge Model Tests

An experimental investigation into the moment carrying capacity of short rigid pier foundations in saturated clay is described. Scale models of square piers with different breadths and depths were used in both conventional and centrifugal studies. The results show that the relationships between moment and rotation are nonlinear but do not exhibit any peak values, and that moment limits, defined by limiting angular rotations, increase with increases in pier depth and breadth. Empirical equations are derived between moment carrying capacity and pier geometry, for a range of limiting rotations, and a very close fit is demonstrated between the moment–rotation relationships obtained using these equations and the actual data obtained from the model tests. It is shown that, at the same pier rotations, the moment carrying capacities observed in the centrifugal model tests are significantly larger than those in the conventional model tests. Numerical analyses of the prototype geometries were also carried out using a three-dimensional nonlinear finite-element computer program. The results are shown to provide satisfactory agreement with the moment–rotation behaviour and working limits observed in the centrifuge model tests. Thus, even though conventional modelling is usually legitimate for determining the immediate bearing capacity of rigid foundations in saturated clay, their rotational stability is shown to be significantly affected by self-weight stresses. Some of the existing methods for designing short piers subjected to moments are examined and compared with the results from the centrifuge model tests. Key words : pier foundation, clay, moment capacity.

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