Seismic Performance of Two Story Steel Building Using Shape Memory Alloys (SMAs) Bars

Shape Memory Alloys (SMA) is type of smart materials that have ability to undergo large deformation and return back to their undeformed shape through heating (shape memory effect) or removal of load (superelastic effect). This unique ability is useful to enhance behavior of structure and seismic resistance. In this paper, superelasticity (SE) effect of NiTi alloys is used to improve the structural characteristics of steel building. The finite element analysis of steel building is done using ABAQUS v.2017. In order to compare the structural behavior of the steel building equipped with Shape Memory Alloy bars at beam-column connection, three steel building was modeled with a different combination of high strength steel bars and SMA bars. The steel building was checked for time history analysis by using Vrancea 1977 earthquake data. In order to estimate the recentring ability, residual of roof displacement and energy dissipation. The steel building equipped with SMA bars shows 82.7%, 152.72%   recovery in residual roof displacement for  steel building equipped with 50% SMA bars and 50% HS steel bars and steel building equipped with 100% SMA bars respectively, and moderate energy dissipation. In general, the frame equipped with 50% superelastic SMA bars and 50% HS steel bars provided better seismic performance

Assessment of Al-Sabtea Bridge under the Effects of Static Loadings

The behavior and strength of composite for composite bridges relay on the connectors that used to connect the steel beams or girders with reinforced concrete deck slab. Different type of shear connectors that available in the market such as headed stud or steel channels are commonly welded to the top face of the steel section to prevent slip at the interface between the two different materials. In present paper, existing composite bridge built in Iraq is modeled using finite elements approach by ANSYS. The bridge is simulate by adopt real dimensions and geometry to check out the performance of connectors and strengths of composite girder under worst static loading conditions proposed by general Iraqi Standard Specification for Road and Bridges such as track, knife and military loadings. The analysis results indicate that the three types applied loading show that all stresses within the acceptable limits and did not reach high values compared capacities of these materials according to the AASHTO ASD code. The maximum stress at bottom face of steel girder is 114.7 MPa and the maximum deflection is 59 mm these values within limits of code.

Finite Element Analysis and Optimization of Steel Girders with External Prestressing

Optimization is a process through which the best possible values of design variables are achieved under the given of constraints and in accordance to a selected optimization objective function. Steel I-girders have been used widely in different fields, which are generally fabricated by connecting two plate flanges, a flat web and a series of longitudinal or transverse stiffeners together. The use of steel girder with external prestressing has been used in many countries as a means of strengthening bridges. The purpose of this paper is to develop a finite element model for the optimization of a steel girder with external prestressing. The ANSYS finite element software package was used to find the optimum cross section dimension for the steel girder. Two objective functions are considered in this study there are optimization of the strain energy and total volume of the girder. The design variables are the width of top flange, the thickness of top flange, the width of bottom flange, the thickness of bottom flange, the height of the web, the width of the web and area of prestressing tendons. Two type of steel girder are considered there are steel girder without prestressing and steel girder with prestressing. The results for volume minimization shows that the optimum cross section for steel girder with prestressing smaller than for steel girder without prestressing

Acute Phase Hyperglycemia among Patients Hospitalized with Acute Coronary Syndrome: Prevalence and Prognostic Significance

AbstractObjectives: Regardless of diabetes status, hyperglycemia on arrival for patients presenting with acute coronary syndrome, has been associated with adverse outcomes including death. The aim of this study is to look at the frequency and prognostic significance of acute phase hyperglycemia among patients attending the coronary care unit with acute coronary syndrome over the in-hospital admission days.Methods: The study included 287 consecutive patients in the Al- Faiha Hospital in Basrah (Southern Iraq) during a one year period from December 2007 to November 2008. Patients were divided into two groups with respect to admission plasma glucose level regardless of their diabetes status (those with admission plasma glucose of <140 mg/dl (7.8 mmol/L) and those equal to or more than that). Acute phase hyperglycemia was defined as a non-fasting glucose level equal to or above 140 mg/dl (7.8 mmol/L) regardless of past history of diabetes.Results: Sixty one point seven percent (177) of patients were admitted with plasma glucose of ≥140 mg/dl (7.8 mmol/L). There were no differences were found between both groups regarding the mean age, qualification, and smoking status, but males were predominant in both groups. A family history of diabetes, and hypertension, were more frequent in patients with plasma glucose of ≥140 mg/dl (7.8 mmol/L). There were no differences between the two groups regarding past history of ischemic heart disease, stroke, lipid profile, troponin-I levels or type of acute coronary syndrome. Again heart failure was more common in the admission acute phase hyperglycemia group, but there was no difference regarding arrhythmia, stroke, or death. Using logistic regression with heart failure as the dependent variable we found that only the admission acute phase hyperglycemia (OR=2.1344, 95�0CI=1.0282-4.4307; p=0.0419) was independently associated with heart failure. While male gender, family history of diabetes mellitus, hypertension and diabetes were not independently associated with heart failure.Conclusion: Admission acute phase hyperglycemia of ≥140 mg/dl (7.8 mmol/L) was associated with heart failure in this study

Simulation of Partial Interaction for Composite Deck of “Al-SABTEA Bridge” Taking The Influence of Static Vehicle loads

The composite bridge has consisted of different materials such as the girder to be steel or precast that connected with deck concrete slab using shear connectors for working as one. In the present study ALSABTEA bridge rehabilitation of the space of the bridge using the composite steel girder existing composite bridge constructed in Diyala-Iraq in 1981 that designed and constructed to behave as full interaction. Representation of composite steel bridge using finite element approach with different parameters to assess the doing of the composite bridge under the effects of static loading using actual dimensions and mechanical properties. The representation of channel shear connectors through elements of COMBIN39 provided simple and powerful modeling of the connectors in comparison with using elements of the 3D solid types. Examining the push-out test and comparing results with the model established by ANSYS proved the proposed numerical model could represent the shear connector's behavior. The difference is small (2.5% to 3.7%) between the model by using the representation shear connector as solid element and combined 39 also, the difference in the results of displacement is small (5%) between the experimental test and model established by ANSYS. The effect has been studied included. Partial and full interaction of Al-SABTEA Bridge under the effects of Static loadings applied at bridge based on Iraqi specification where the final assessment the results deflection within permissible limits according to all models