Browsing by Author "Rahman, Jesika"

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BEHAVIOR OF CONCRETE FILLED STAINLESS STEEL TUBULAR COLUMN UNDER AXIAL LOADS
(R&D Wing, MIST, 2019-12) Sanaullah, Lieutenant Colonel Muhammad; Rahman, Jesika; Ibrahim, Ibriju; Rahman, Major Md. Soebur
# $ % #& ! '( '( % core concrete. A CFSST column has gained prominence from structural engineers all over the world as it provides " % ) '( * + ( ' ( * $ ) ) $ % #& ! ) % % / ( $ ' '% various constructions. This paper presents a detailed experimental and numerical study on the compressive behavior of $ % ' %8 " ; ) % '( < ' ' * ( " " ( ( $ ' &= ) >?>G+ have been validated using the experimental data of the present study as well as recently published test results. The FE models predict the experimental load-deformation behavior, ultimate strength and failure modes with good accuracy. Once the FE model is validated, the numerical results are compared with the existing conventional carbon steel design code/guidelines and developed a prediction formula for CFSST columns.
Comparative Study of Physical and Mechanical Properties of Machine and Manually Crushed Brick Aggregate Concrete
(R&D Wing, MIST, 2020-06) Islam, Md J.; Rahman, Jesika; Nawshin, Sadia; Islam, Mohammad M.
With technological advancement on the rise, manual crushing of bricks is gradually being replaced by machine crushing to obtain coarse aggregates for construction. However, properties of the brick aggregates obtained from these two methods vary which in turn, may affect the properties of the concrete matrix as well. This study represents a comparison between the machine crushed and manually crushed brick aggregates to be used as coarse aggregates in preparation of concrete. Four types of bricks, namely first class, second class, picket (over burnt) and ceramic were investigated, and each was crushed both manually and mechanically to a usable form of aggregates. The physical and mechanical properties of the brick aggregates derived from the two methods were tested and compared. In all types of brick, aggregates size, shape and strength properties such as flakiness and elongation indices, aggregate impact and crushing values and Los Angeles abrasion value showed lower values for manually crushed aggregate indicating better properties compare to machine crushed aggregates. This was evident while comparing compressive and tensile strength of concrete prepared with both manually and machine crushed first class and picket brick aggregates. Concrete with manually crushed brick aggregates showed marginally higher compressive and tensile strength in both types of brick aggregates.