ANSYS 10.0, a finite element software, has been used to simulate simply supported RC beams consisting of circular openings with varying diameters in 3-D nonlinear finite element method. The RC beam model is created using SOLID65, SOLID45 and LINK8 elements representing both linear and non-linear behavior of concrete, steel plate and reinforcing bar respectively. The inherent assumption is that there is full displacement compatibility between the reinforcement and the concrete and no bond slippage occurs. The FE beam model is verified against experimental test data of RC solid beam without opening available in literature and then a number of verified models of simply supported RC beams with circular opening are loaded monotonically with two incremental concentrated loads. A model with equivalent square opening of 133 mm in width is also analyzed. An attempt is made to know the effects of circular opening size on the behavior of RC beams from load-deflection curve, crack pattern and stress distribution. RC rectangular beams with circular openings of diameter less than 44% of the depth of beam (D) has no effect on the ultimate load capacity but circular openings with diameter more than 44% of D reduces the ultimate load capacity at least 34.29%.

<p><em>Background:</em> Dengue virus infections are a significant threat to human populations particularly in the tropical and subtropical regions. This is mainly transmitted by Aedes aegypti mosquito from humans to humans. The main pathological mechanisms associated include thrombocytopenia, haemorrhagic diathesis with haemoconcentration. Ultrasonography is used because of its ability to detect plasma leakage signs and prediction of disease severity.</p> <p><em>Objective:</em> To evaluate the usefulness of ultrasonographic findings of dengue fever and its correlation with platelet count.</p> <p><em>Methods:</em> It was a prospective observational study, carried out in Bangladesh Medical College Hospital, Dhaka from May 2019 to August 2019. A total of 213 patients of suspected dengue fever during the epidemic were included in this study. All the cases were serologically diagnosed and evaluated with ultrasonographic findings. Platelet counts were estimated in all the cases and compared with findings recorded on ultrasonographic findings.</p> <p><em>Results:</em> The mean age of the study population was 28.7 years. The male female ratio was 1.7:1. The common features on ultrasonography were thickened and oedematous gall bladder wall, mild to moderate ascites, pleural effusion (unilateral and bilateral), and hepatosplenomegaly. Thickened and oedematous gall bladder wall were observed in 68.8%, mild to moderate ascites 65.3%, bilateral pleural effusion 58.2 %, unilateral pleural effusion 40.4%, hepatomegaly 34.3 % and splenomegaly 13.6 % Platelet counts were significantly lower in abnormal ultrasonographic findings (<em>p</em>=0.001).</p> <p><em>Conclusion:</em> In a febrile patient with thrombocytopenia and positive dengue serology, ultrasonography of the abdomen is a useful tool to evaluate the severity of illness. Ultrasound findings of gall bladder wall oedema, ascites, and pleural effusion were correlated with the severity of thrombocytopenia. In epidemic scenarios, Ultrasonographic features may help in roughly estimating the platelet count even before serology and platelet results are available. Thus, it helps in treatment planning without waiting for the laboratory results.</p> Bangladesh Med Res Counc Bull 2021; 47(1): 23-28