Evaluation of Redundancy in Composite Twin-Tub-Girder Bridges with Finite Element Analysis

High torsional rigidity and attractive aesthetics in construction of twin-tub-girder bridges make them preferable for the design of curved bridges. However, according to the concepts associated with the term “Fracture Critical (FC)” that are in place today, all two-girder bridges are always classified as having FC members. For a steel bridge with FC members, the fracture of any of its members may result in complete catastrophic failure or significant loss of serviceability; hence, every two years twin-tub-girder bridges are subjected to very expensive hands-on field inspection. Full-scale simple span twin-tub-girder bridge tests at University of Texas Austin have demonstrated excessive load capacity of a fractured simple span bridge. A significant number of twin-tub-girder bridges might be classified as redundant; however, this individual test is not adequate to define the comprehensive damage behavior of twin-tub-girder bridges in general. In this dissertation, 3D non-linear (material and geometric) detailed finite element (FE) analysis procedures which have been calibrated from full-scale testing providing confidence in the results were developed. The FE models included all the plastic and damage behavior of reinforced concrete deck, brace connections, all steel components of the super structure, stages of construction, and the effects of the dynamic amplification of the bridge immediately following the fracture. Detail work was also performed to define comprehensive shear stud behavior

Fatigue Categorization of Obliquely Oriented Welded Attachments

In current bridge design specifications and evaluation manuals from the American Association of State Highway and Transportation Officials (AASHTO LRFD) (AASHTO, 2018), the detail category for base metal at the toe of transverse stiffener-to-flange fillet welds and transverse stiffener-to-web fillet welds to the direction of the web and hence, the primary stress) is Category C′. In skewed bridges or various other applications, there is sometimes a need to place the stiffener or a connection plate at an angle that is not at 90 degrees to the web. As the plate is rotated away from being 90 degrees to the web, the effective “length” of the stiffener in the longitudinal direction increases. However, AASHTO is currently silent on how to address the possible effects on fatigue performance for other angles in between these two extremes. This report summarizes an FEA study that was conducted in order to investigate and determine the fatigue category for welded attachments that are placed at angles other than 0 or 90 degrees for various stiffener geometries and thicknesses. Recommendations on how to incorporate the results into the AASHTO LRFD Bridge Design Specifications are included in this report

Member-Level Redundancy of Built-Up Steel Axially Loaded Members

Full-scale fracture tests were completed determining that mechanically-fastened steel built-up axially-loaded tension members are resistant to running fracture when a single component suddenly fractures. This characteristic of built-up member is referred to as Cross-Boundary Fracture Resistance (CBFR). A comprehensive finite element model-based parametric study was also performed investigating the post-fracture load redistribution behavior of multi-component built-up members. Simplified closed-form solutions were developed for engineering analysis of built-up members to evaluate for internal member redundancy and estimate safe inspection intervals that are based on the fatigue life of the member in the assumed faulted condition

Ganglion cysts in the lateral portal region of the knee after arthroscopy: report of two cases

A ganglion cyst (GC) is a mucinous or gelatinous-filled benign tumor overlying a joint or tendon sheath, which commonly arises in the dorsal and volar wrist side but may occur anywhere in the body. Although cystic lesions around the knee are common, the occurrence of GCs are rare. Ganglia may arise from intra or extra-articular, soft tissue, intraosseous, or periosteal location. Symptoms may vary according to the size and location. After the more frequent performance of magnetic resonance imaging for the assessment of a knee joint, the number of incidental, asymptomatic lesions have been increasingly diagnosed. The etiology of GC remains unclear; however, trauma and a flaw in the joint tissues may explain its appearance. The authors report two cases of women aged 47 years and 37 years who presented pain and swelling in their left knees following arthroscopic partial medial meniscectomy. The former was surgically treated and had a favorable outcome, while the latter had conservative treatment and a gloomy outcom

Member-Level Redundancy of Built-Up Steel Girders Subjected to Flexure

The purpose of this research was to describe the behavior of mechanically fastened built-up girders in a partially failed condition. This was achieved by testing large-scale riveted and high-strength bolted built-up specimens to determine their fracture resilience at low temperatures and their fatigue capacity after a single component was failed. Additionally, a finite element parametric study was performed to understand the behavior of built-up girders and to better describe the load distribution that occurs locally in the region adjacent to a failed component

A Simplified Approach for Designing SRMs in Composite Continuous Twin-Tub Girder Bridges

High torsional rigidity and attractive aesthetics in construction of twin-tub girder bridges make them preferable for the design of curved bridges. However, according to the concepts associated with the term “Fracture Critical (FC)” that are in place today, all two-girder bridges are classified as having FC members (FCMs) due to their perceived lack of load path redundancy. For a steel bridge with FCMs, the fracture of any of the FCMs is assumed to result in complete catastrophic failure or significant loss of serviceability; hence, every two years twin-tub girder bridges undergo very expensive hands-on field inspections. This report presents a simplified approach to ensure newly designed twin-tub girder bridges will meet all the requirements defined in the 2018 AASHTO Guide Specifications without performing in-depth FEA. AASHTO-ready proposed specifications are included in Appendix A. It is anticipated that these provisions could be incorporated into the AASHTO LRFD BDS as a new article 6.6.3 Special Provisions for Twin Tub Girder Bridges

Adolescent pregnancies: complications, birth outcomes and the possible solutions

Objectives: In this study we aim to evaluate antenatal, perinatal and postnatal outcomes and complications of adolescent pregnancies, as well as to discuss the social and psychological consequences of these pregnancies. Material and methods: We compare a total of 243 pregnant women at age 14–18 years to a vast control group at age 19–36 who all delivered at Bursa Yüksek Ihtisas Training and Research Hospital between years 2005–2014. Results: Antenatal care (folic acid supplementation, pre-conception counseling) was significantly higher in adolescent pregnancy group. Unplanned pregnancy rate was significantly higher in in study group (p < 0.001). Preterm delivery (before 37th week) ratio was statistically higher in pregnancy complications. Conclusions: Adolescent pregnancy is a social entity which should be regulated and prevented by legal measures. Planned pregnancies should be promoted and the public should be educated and informed about the Hazards of adolescent pregnancies. Press institutions, public broadcasting services support the efforts to decrease adolescent pregnancies

Serum osteopontin levels in patients with psoriasis vulgaris and its relation with oxidative stress

Background and Design: Oxidative stress is known to play a role in the etiopathogenesis of psoriasis. Recent data suggest that osteopontin (OPN) can also play a role in the pathogenesis of psoriasis. In the current study, OPN levels and oxidative stress were evaluated in patients with psoriasis. Materials and Methods: The study included 61 patients with psoriasis and 62 healthy controls. The OPN levels, total antioxidant status (TAS), total oxidant status (TOS), and oxidative stress index (OSI) were measured using serum. The disease severity was evaluated using the psoriasis area and severity index (PASI). Results: No statistically significant differences in OPN, TAS, and OSI values were identified between the psoriasis and control groups. A negative correlation was found with the TAS. There was no statistically significant correlation between the PASI score and OPN, TAS, TOS, and OSI values. Conclusion: We did not find a statistically significant correlation between OPN levels and oxidative stress in patients with psoriasis. We believe that larger and more detailed studies are needed to highlight the role of OPN and oxidative stress in the etiopathogenesis of psoriasis

Evaluation of the awareness of the physicians on negligence and abuse of the elderly patients admitted to emergency department

Introduction: With the increase in the population of the elderly, the negligence and abuse of the elderly (NAE) is increasing at a great pace. Although the rates of NAE in the elderly admitted to emergency depart- ment (ED) is more than the estimated rates, the diagnosis and reporting of such cases are extremely rare. The primary aim of the present study is to evaluate the NAE status in the elderly admitted to ED, the awareness in ED physicians, the attitudes towards these cases and the knowledge levels in this field.  Methods: An electronic questionnaire form that was used as the data collection tool consisted of 19 ques- tions and 2 sections. To call for participation, the questionnaires used in the study were shared with the ED physicians in an online manner between December 2017 and April 2018. The data were analyzed with the SPSS 23.0 Windows computer program with definitive statistics.  Results: A total of 69.4% of the participants faced NAE and 30% did not report this; 79.8% of the partic- ipants stated that they had received training in this field and 9% stated that there was a screening test for the abuse of the elderly. A statistically significant difference was determined between those who received course training in this field and those who received training during medicine faculty education and specialist training.  Conclusions: In this study, it was observed that the NAE rates were more than the estimated rates in the elderly admitted to ED. It was understood that ED physicians did not have adequate knowledge in this field. A new curriculum is needed for the training and education in this field. 

Ganglion cysts in the lateral portal region of the knee after arthroscopy: report of two cases

A ganglion cyst (GC) is a mucinous or gelatinous-filled benign tumor overlying a joint or tendon sheath, which commonly arises in the dorsal and volar wrist side but may occur anywhere in the body. Although cystic lesions around the knee are common, the occurrence of GCs are rare. Ganglia may arise from intra or extra-articular, soft tissue, intraosseous, or periosteal location. Symptoms may vary according to the size and location. After the more frequent performance of magnetic resonance imaging for the assessment of a knee joint, the number of incidental, asymptomatic lesions have been increasingly diagnosed. The etiology of GC remains unclear; however, trauma and a flaw in the joint tissues may explain its appearance. The authors report two cases of women aged 47 years and 37 years who presented pain and swelling in their left knees following arthroscopic partial medial meniscectomy. The former was surgically treated and had a favorable outcome, while the latter had conservative treatment and a gloomy outcom