Behavior of Beam to Column Cold-Formed Section Connections Subjected to Bending Moments

Cold formed sections are often used in the construction of mid-rise buildings due to their high strength weight ratios, and fast erection. In these buildings, the connections between joists and studs are mainly simple connections. However, application of these sections can be extended to moderate span frames where connections between members are subjected to bending moments. Strength and stability of such frames depends to large extent on the behaviour of the connections between their members. Over the last twenty years, several researchers undertake tests on cold formed section connections subjected to bending moments. Major of them classify the connections as semi-rigid, but some suggested that as we reach the maximum capacity of the connected sections so we can consider it rigid

Perspective Chapter: The Toxic Silver (Hg)

In the late 1950s, residents of a Japanese fishing village known as “Minamata” began falling ill and dying at an alarming rate. The Japanese authorities stated that methyl-mercury-rich seafood and shellfish caused the sickness. Burning fossil fuels represent ≈52.7% of Hg emissions. The majorities of mercury’s compounds are volatile and thus travel hundreds of miles with wind before being deposited on the earth’s surface. High acidity and dissolved organic carbon increase Hg-mobility in soil to enter the food chain. Additionally, Hg is taken up by areal plant parts via gas exchange. Mercury has no identified role in plants while exhibiting high affinity to form complexes with soft ligands such as sulfur and this consequently inactivates amino acids and sulfur-containing antioxidants. Long-term human exposure to Hg leads to neurotoxicity in children and adults, immunological, cardiac, and motor reproductive and genetic disorders. Accordingly, remediating contaminated soils has become an obligation. Mercury, like other potentially toxic elements, is not biodegradable, and therefore, its remediation should encompass either removal of Hg from soils or even its immobilization. This chapter discusses Hg’s chemical behavior, sources, health dangers, and soil remediation methods to lower Hg levels

Parametric study of the structural and in-plane buckling analysis of ogee arches

As part of a pilot project an ogee arch is being studied as a self-supporting skin skylight for the Housing and Building National Research Center’s (HBRC) patio. The ogee arch consists of a pair of two tangential circular arcs making an arch shape. The geometry of the arch depends on several interrelated variables including the angles subtended by the arcs, the ratio of the radii of the two arcs, and the height of the arch. This paper provides curves for designing the geometry of ogee arches. The structural analysis of two-hinged ogee arches under different cases of loading is outlined deriving expressions for the horizontal base thrust and plotting their graphs. A parametric study of the antisymmetric in-plane buckling behavior of ogee arches is presented using a finite element eigenvalue buckling analysis for several cases of loading. The finite element models consist of beam elements and have varying geometrical dimensions representing different shapes of ogee arches. The structural response of the arches is verified through a linear finite element analysis. The results of the buckling analysis are verified through a nonlinear finite element analysis with initial imperfections. It is found that the buckling load is a function of the ratio of the height-to-base radius of the arch and expressions for the lower bound buckling load are derived as a function of this height-to-base radius ratio