Papers by Arman Chowdhury
Performance based seismic design philosophies in seismic design has become the cardinal point of ... more Performance based seismic design philosophies in seismic design has become the cardinal point of interest in civil engineering structures Due to the vulnerability of Bangladesh to earthquake, base isolation system should be introduced in major earthquake zone. To see the dynamic behaviour of the structure, dynamic analysis should be performed for regular and irregular building with and without isolator. Dynamic analysis can take the form of a dynamic time history analysis or a linear response spectrum analysis. The installation of isolator in building considerably increases the time period of the structure, which means it reduces the possibility of resonance of the structure. Provision of isolator in building often increase the total cost, but as reinforcement requirement and construction material cost is reduced due to isolator. So, isolator may be incorporated at the bottom of the structure to exploit economic and structurally safe alternative. In this present study, Multi-storey ...
Driven by a need to reduce repair costs and downtime in structures following a major earthquake, ... more Driven by a need to reduce repair costs and downtime in structures following a major earthquake, self-centering (SC) systems have been introduced. Post-tensioned (PT) high strength steel strands have shown promising results in providing the SC capability in steel frames, where the beams are compressed to columns. In this study, the lateral cyclic performance of the SC connections is assessed through finite element analysis. At the beginning, the lateral load-deformation behavior of previously tested experimental specimens is validated with three-dimensional finite element models. The validated models are then modified accordingly to investigate the applicability of other techniques, i.e. stiffened angle connection, or other types of materials, i.e. shape memory alloy (SMA). Through design of experiment methodology, parametric studies in component level, i.e. stiffened angle, are conducted to provide some insight into the effect of different stiffener sizes on the strength and energy dissipation capacity of the connection. Afterward, four different techniques of incorporating SMA in the SC connections are proposed based on extensive parametric studies. Segmented PT connection is possible with shorter length SMA strand which can even sustain higher drift demand compared to the SC connections with steel strand. Hybrid strand, i.e. combination of steel strand and SMA strand, can further reduce the amount of SMA material in the connection. The use of SMA angles as energy dissipaters will remove the need for the replacement of the energy dissipating elements due to damage. Lastly, the applicability of SMA bolts in end-plate based interior and exterior connections are investigated through a parametric study.
Epidemiologia, 2020
As other nations around the world, Bangladesh is facing enormous challenges with the novel corona... more As other nations around the world, Bangladesh is facing enormous challenges with the novel coronavirus (COVID-19) epidemic. To design a prevention and control strategy for this new infectious disease, it is essential to first understand people’s knowledge, attitudes, and practices (KAP) regarding COVID-19. This study sought to determine KAP among rural and urban residents as well as predictors of preventive practices associated with COVID-19 in Bangladesh. A social media-based (Facebook) cross-sectional survey was conducted to explore these variables among Bangladeshi adults. Of 1520 respondents who completed the questionnaire, low level of good or sufficient knowledge of COVID-19 (70.8%) and practices associated with COVID-19 (73.8%) were found. Despite the low level of knowledge and practices, respondents’ attitude (78.9%) towards COVID-19 was relatively high. Results suggest that compared to urban, rural residents are at a particularly high risk of COVID-19 because they were foun...
Journal of Civil & Environmental Engineering, 2015
The use of Fiber Reinforced Polymer (FRP) bars to reinforce concrete structures has received a gr... more The use of Fiber Reinforced Polymer (FRP) bars to reinforce concrete structures has received a great deal of interest in recent days due to their high tensile strength, corrosion resistance and good non-magnetization properties. Whether to pick FRP bars due to their low modulus of elasticity over conventional steel, to be used in beams, is the major concern of a designer. FRP bars show low strength in shear as they are more elastic than steel. Recently, researchers have developed a number of models to predict the shear strength of FRP-reinforced concrete, but none of them have yet been capable of determining the results satisfactorily. Here a comparative study among different codes and models as suggested by the researchers has been conducted to predict the shear strength of FRP reinforced concrete beams. To facilitate the comparison a database of 104 beams have been presented, which are composed of shear span-to-depth ratio, a/d ranged from 2.5 to 6.5, shear span, (a) ranges from, 600 to 1219, concrete compressive strength, (fc') 24.1Mpa to 81.4MPa, Modulus of elasticity of FRP bars, (Ef) varies between 32GPa to 145GPa, longitudinal reinforcement ratio, (Pf) varies between 0.25 to 3.02. The database contains beams and slabs without transverse reinforcement. The guidelines, codes and models that have been implemented and compared in this study consist of ACI 440.1R-03, CSA S806-06, CSA S806-08, CSA S806-11, JSCE-1997, ISIS-M03-01 2001, BISE guideline 1999. It was observed from the statistical analysis that model proposed by Kara 2011 exhibited the overall best performance to predict the shear strength of FRPreinforced beams.
IOSR Journal of Mechanical and Civil Engineering, 2013
Introduction of the flexible element at the base of a structure and at the same time ensuring dam... more Introduction of the flexible element at the base of a structure and at the same time ensuring damping is probably the best option for the seismic isolation technique. The device that meets such criteria is known as isolator. In this study incorporation of such base isolator in buildings has been investigated. A study was done considering different building with different plan to justify the applicability of base isolation. The characteristics and performance effect of a building with and without base isolator system were compared. Study shows the applicability of base isolator to the range up to buildings of 30m-40m height. The installation of isolator in building considerably increases the time period of building, which means it reduces the possibility of resonance of the structure. Provision of isolator in building often increases the total cost, but reinforcement requirement and construction material cost is reduced due to isolator. So, isolator may be incorporated at the bottom of the building to exploit economic and structurally safe alternative.
In recent years, brittle failures of so many reinforced concrete structures are observed during e... more In recent years, brittle failures of so many reinforced concrete structures are observed during earthquakes and other deadly forces. In this regard, concrete researchers are intended to improve the ductility of the RC structure by using steel fiber to make concrete a composite material with enhanced capacities. To this end, this research concentrates on the applicability of steel fiber reinforced concrete (SFRC) in construction industry of Bangladesh by providing validated Finite Element (FE) models of experimental results. Experimental investigations show promising outcomes by using steel fibers in flexural specimens. Results of plain concrete and steel fiber reinforced concrete (SFRC) beam specimens are compared. SFRC beam specimens showed an increase of about 8% to 60% flexural capacity enhancement. Flexural specimens are then modeled in the Finite Element (FE) platform of ANSYS 10.0. Material property and boundary condition are applied on the basis of experimental data and test ...
Journal of Case Reports and Images in Oncology, 2017
Introduction: Secretory carcinoma is a rare lowgrade breast carcinoma. Although originally descri... more Introduction: Secretory carcinoma is a rare lowgrade breast carcinoma. Although originally described in children, it is now known to occur in adults of both sexes. Distant metastases from secretory carcinoma are extremely rare but the overall incidence of axillary lymph node infiltration is around 30% in children and adults regardless of gender. Case Report: This paper includes a case report of secretory carcinoma in a young girl, which was managed by surgical treatment including local recurrence but no other adjuvant therapy. Conclusion: Secretory breast carcinoma can be a diagnostic challenge histologically. In the absence of any consensus guidelines, treatment decisions are based on data extrapolated from more common varieties of breast cancer.
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Papers by Arman Chowdhury