scholarly journals Effects of Shear Tabs and High-Strength Bolts in Seismic Performance of Steel Moment Connections

Buildings ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 415
Author(s):  
Chi-Ming Lai ◽  
Ching-Yu Yeh ◽  
Sin-Yu Kang ◽  
Heui-Yung Chang
Keyword(s):  
Stress Concentration ◽  
High Strength ◽  
The Other ◽  
Moment Connections ◽  
Moment Capacity ◽  
Peak Loads ◽  
Shear Tab ◽  
H Beam ◽  
Demand And Capacity ◽  
The U.S

A shear tab and high-strength bolts are often used to connect a steel H-beam to a column. The design demand and capacity of these elements vary from one standard to the other. To investigate the effect, this study applied a finite element method (FEM) to develop models for two steel moment connections and validated the effectiveness by test data. The connections were characteristic of bolted-web-and-welded-flange details. The FEM models were then used to study the design of shear tabs and high-strength bolts in accordance with the U.S. and Japan standards and compared to the Taiwan practice. The result showed a small difference in the peak loads of the connections. However, the U.S. direct welded flange connection had flange buckling and strength degradation at a relatively smaller drift. The connection had a thinner shear tab and fewer high-strength bolts. The other two connections had very similar design results and loading responses. The increase in shear-tab thickness reduced the stress concentration and fracture potential of the connections. It is, therefore, recommended to design a shear tab with moment capacity greater than the beam web. This will reduce the stress concentration of the base metal surrounding the beam-flange groove welds, increasing the connection ductility.

Life Beyond 1MeV

1980 ◽  
Vol 38 ◽  
pp. 30-33
Author(s):  
K.H. Westmacott
Keyword(s):  
Electron Microscopy ◽  
Past Experience ◽  
The Other ◽  
Good Case ◽  
Other Hand ◽  
The U.S

Life beyond 1MeV – like life after 40 – is not too different unless one takes advantage of past experience and is receptive to new opportunities. At first glance, the returns on performing electron microscopy at voltages greater than 1MeV diminish rather rapidly as the curves which describe the well-known advantages of HVEM often tend towards saturation. However, in a country with a significant HVEM capability, a good case can be made for investing in instruments with a range of maximum accelerating voltages. In this regard, the 1.5MeV KRATOS HVEM being installed in Berkeley will complement the other 650KeV, 1MeV, and 1.2MeV instruments currently operating in the U.S. One other consideration suggests that 1.5MeV is an optimum voltage machine – Its additional advantages may be purchased for not much more than a 1MeV instrument. On the other hand, the 3MeV HVEM's which seem to be operated at 2MeV maximum, are much more expensive.

Development of Low Carbon High Strength H-Beam Steel

2010 ◽  
Vol 168-170 ◽  
pp. 969-972
Author(s):  
Jian Qing Qian ◽  
Ji Ping Chen ◽  
Bao Qiao Wu ◽  
Jie Ca Wu
Keyword(s):  
Mechanical Properties ◽  
Laboratory Experiments ◽  
Theoretical Study ◽  
High Strength ◽  
Rolling Process ◽  
Low Carbon ◽  
Study Product ◽  
H Beam ◽  
Nitrogen Alloy

The application of vanadium-nitrogen alloy to develop a certain low carbon high strength H-beam steel was determined through the combination of theoretical study, product requirements and existing practical conditions. The specific rolling process was further defined through laboratory experiments. The developed low carbon high strength H-beam steel was trial produced and its properties were also analyzed. The results showed that the newly developed low carbon high strength H-beam steel had excellent mechanical properties and good weldability.

Design of a novel HSLA steel with a combination of high strength (140–160 ksi) and excellent toughness

2021 ◽  
Vol 112 (10) ◽  
pp. 800-811
Author(s):  
Mehdi Soltan Ali Nezhad ◽  
Sadegh Ghazvinian ◽  
Mahmoud Amirsalehi ◽  
Amir Momeni
Keyword(s):  
Impact Toughness ◽  
Yield Strength ◽  
Hsla Steel ◽  
Charpy Impact ◽  
High Strength ◽  
Controlled Rolling ◽  
The Other ◽  
Grain Structure ◽  
Charpy Impact Toughness ◽  
Fine Grain

Abstract Three steels were designed based on HSLA-100 with additional levels of Mn, Ni, Cr and Cu. The steels were prepared by controlled rolling and tempered at temperatures in range of 550–700°C. The continuous cooling time curves were shifted to longer times and lower temperatures with the increased tendency for the formation of martensite at lower cooling rates. The microstructures revealed that controlled rolling results in austenite with uniform fine grain structure. The steel with the highest amount of Mn showed the greatest strength after tempering at 750 °C. The top strength was attributed to the formation of Cu-rich particles. The steel with 1.03 wt.% Mn, tempered at 650 °C exhibited the best Charpy impact toughness at –85°C. On the other hand, the steel that contained 2.11 wt.% Mn and tempered at 700 °C showed the highest yield strength of 1 097.5 MPa (∼159 ksi) and an impact toughness of 41.6 J at –85°C.

Russia in B. Obama's Foreign Policy Strategy: Continuation and Renovation

2010 ◽  
pp. 46-55
Author(s):  
E. Solov’ev
Keyword(s):  
Foreign Policy ◽  
Balance Of Power ◽  
The Other ◽  
Policy Strategy ◽  
The U.S ◽  
Barak Obama

Unlike his predecessors, Barak Obama is bound to work amidst global balance of power rapidly changing to the disfavor of American interests. All attempts of the U.S. to build an unipolar world under its domination have failed. Obama is vigorously seeking to restructure U.S.–Russia relations; however, the divergence of interests in many fields is evident, and neither Washington nor Moscow can agree on the partnership as formulated by the other side.

scholarly journals STRUCTURAL BEHAVIORS OF CONCRETE FILLED SQUARE TUBULAR HIGH STRENGTH STEEL COLUMN TO H-BEAM CONNECTIONS

1993 ◽  
Vol 446 (0) ◽  
pp. 127-136 ◽  
Author(s):  
Koji MORITA ◽  
Masaru TERAOKA ◽  
Takahiko SUZUKI ◽  
Toshio FUJIWARA ◽  
Hisaaki YABUSAME
Keyword(s):  
High Strength Steel ◽  
High Strength ◽  
Steel Column ◽  
H Beam ◽  
Structural Behaviors

Stress Concentration at the Root of Bolt Thread

2010 ◽  
Author(s):  
Yasumasa Shoji ◽  
Toshiyuki Sawa
Keyword(s):  
Finite Element Analysis ◽  
Stress Concentration ◽  
Concentration Factor ◽  
The Other ◽  
Special Technique ◽  
Allowable Stress ◽  
Element Analysis ◽  
Bolt Stress ◽  
Thread Root ◽  
External Loads

The bolt strength is determined based on the concentrated bolt stress at the thread roots. The allowable stress is determined so that the thread root will not yield by the pretension and the external loads, using the stress concentration factor obtained as 3 to 5 from experiments. However, the concentration factor is not clear so far, as it is quite difficult to measure the stress at such a localized region. On the other hand, structural analysis, namely finite element analysis, has the possibility to provide the most-likely stress at the thread root. In this paper, a special technique, a.k.a. submodelling, is used to calculate the stress distribution at thread surfaces very precisely. The result will be useful to solve any stress related problems.

Policy Report ~ Informe

2016 ◽  
Vol 32 (2) ◽  
pp. 357-378 ◽  
Author(s):  
Patricia Gándara
Keyword(s):  
Young People ◽  
Academic Preparation ◽  
The Other ◽  
Dropping Out ◽  
Job Opportunities ◽  
Mexican Schools ◽  
The U.S

Millions of young people receive part of their education in the U.S. and part in Mexico. However, neither the U.S. nor Mexican schools are prepared to educate students from “the other side.” This commonly results in loss of school credit, poor academic preparation and dropping out, which leads to very limited job opportunities and wasted human talent. This article suggests several ways in which this problem can be addressed. Millones de jóvenes reciben parte de su educación en los Estados Unidos y parte en México. Sin embargo, ni las escuelas de los Estados Unidos ni las de México están preparadas para educar a los estudiantes “del otro lado”. Esta situación comúnmente resulta en la pérdida de créditos escolares, la mala preparación académica y en el abandono de los estudios, lo que conduce a muy limitadas oportunidades de empleo y al desperdicio de talento humano. Este artículo sugiere varias maneras en las cuales se puede abordar este problema.

scholarly journals Current Nuclear Strategies and Arsenals of the United States of America and the Russian Federation

2021 ◽  
Vol 30 (4) ◽  
pp. 23-44
Author(s):  
Adam Potočňák
Keyword(s):  
Cold War ◽  
United States Of America ◽  
The United States ◽  
The Other ◽  
Nuclear Forces ◽  
Nuclear Strategy ◽  
The Usa ◽  
The Russian Federation ◽  
The Cold War ◽  
The U.S

The article holistically analyses current strategies for the use and development of nuclear forces of the USA and Russia and analytically reflects their mutual doctrinal interactions. It deals with the conditions under which the U.S. and Russia may opt for using their nuclear weapons and reflects also related issues of modernization and development of their actual nuclear forces. The author argues that both superpowers did not manage to abandon the Cold War logic or avoid erroneous, distorted or exaggerated assumptions about the intentions of the other side. The text concludes with a summary of possible changes and adaptations of the American nuclear strategy under the Biden administration as part of the assumed strategy update expected for 2022.

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