Numerical and Experimental study of pounding damages in adjacent bridge structures subjected to spatially varying ground motion and its mitigation method

Bridge infrastructure is an integral component of the transportation network with significant strategic value and is expected to remain functional in the damaged area immediately after a strong earthquake. However, previous experiences have shown that keeping the bridges operational after a strong earthquake is very challenging. This study investigates the damages resulting from pounding and unseating at bridge superstructure and residual deformation of bridge substructure subjected to earthquake loading, and the possible mitigation methods

Devices for protecting bridge superstructure from pounding and unseating damages: an overview

Previous earthquakes have highlighted the seismic vulnerability of bridges due to excessive movements at expansion joints. This movement could lead to the catastrophic unseating failure if the provided seat width is inadequate. Moreover, seismic pounding is inevitable during a strong earthquake due to the limited gap size normally provided at the expansion joints. Various types of restrainers, dampers and other devices have been proposed to limit the joint movement or to accommodate the joint movement so that the damages caused by excessive relative displacements could be mitigated. To select and design appropriate devices to mitigate the relative displacement-induced damages to bridge structures during earthquake shaking, it is important that results from the previous studies are well understood. This paper presents an overview on various pounding and unseating mitigation devices that have been proposed by various researchers. Based on an extensive review of up-to-date literatures, the merits and limitations of these devices are discussed

Groin hit death due to femoral vein rupture in a drug abuser

Recreational drug use is becoming  an  imminent social and health problem throughout the world. Intravenous injection for drug misuse has been described in both the upper and lower limbs and is a major cause of millions of deaths each year; deaths are primarily due to fatal overdose and the trauma and infection caused by repeated injections. This paper presents an accidental death due to massive blood loss, which resulted from rupture to the right femoral vessel based on autopsy findings. In case of accidental injuries, a thorough medico-legal process, including death scene investigation, autopsy examination and toxicological analyses,  are  always necessary to determine the manner of death

Spontaneous bacterial peritonitis due to streptococcus pneumoniae: a case report

Despite not being a normal gastrointestinal flora, Streptococcus pneumoniae can be the causative agent of Spontaneous Bacterial Peritonitis (SBP) in clinical setting. Patient present with fever, progressive abdominal pain, swelling of limbs, abdomen or both. It is mainly diagnosed by ascitic fluid tapping and its cell count along with culture and sensitivity. This condition has very good response with antibiotics as per culture reports. Here, we present a common case of SBP caused by an uncommon pathogen Streptococcus pneumoniae

Effect of different nitrogen levels on yield and yield attributes of different rice varieties in DDSR condition at Kanchanpur, Nepal

An experiment on the effect of different nitrogen levels on yield and yield attributes of different rice varieties was conducted in Kanchanpur, Nepal, from March 2021 to July 2021. The experiment was laid in randomized complete block design with two factors: nitrogen levels and rice varieties, each factor having three levels (Nitrogen: 60kg/ha, 120kg/ha, and 180kg/ha and rice varieties: Hardinath 1, Hardianth 3 and Chaite 5) resulting in nine treatment combinations. Rice seeds were sown directly in experimental plots under the dry condition on March 24, 2021. The plant spacing was 20x20cm^2. Growth parameters, grain yield, and yield attributing traits of rice were recorded. The statistical results revealed significant differences between the treatments regarding agronomical parameters, yield attributing characters, and grain yield. The results indicated that the 180 kg/ha level of N application contributes to the higher plant height (74.502 cm), the number of tillers (1101.667), effective tillers (577.222), filled grain per panicle (116.490), panicle length (25.241 cm), grain yield (4.7 ton/ha) and straw yield (10.564 ton/ha). Among the varieties, Hardinath 3 produced significantly higher plant height (79.68 cm), panicle length (25.68cm), sterility percentage, and 1000 grain weight (24.60g) as compared to Hardinath 1 and Chapter 5, respectively. However, yield and yield attributing characters like grain yield, straw yield, effective tillers, and filled grains per panicle were significantly higher in Chaite 5. Therefore, a nitrogen level of 180 kg/ha and variety Chaite5 may be used for better productivity in Kanchanpur, Nepal

Experimental and three-dimensional finite element method studies on pounding responses of bridge structures subjected to spatially varying ground motions

Pounding and unseating damages to bridge superstructures have been commonly observed in many previous major earthquakes. These damages can essentially attribute to the large closing or opening relative displacement between adjacent structures. This article carries out an experimental study on the pounding responses of adjacent bridge structures considering spatially varying ground motions using a shaking table array system. Two sets of large-scale (1:6) bridge models involving two bridge frames were constructed. The bridge models were subjected to the stochastically simulated ground motions in bi-direction based on the response spectra of Chinese Guideline for Seismic Design of Highway Bridge for three different site conditions, considering three coherency levels. Two types of boundary conditions, that is, the fixed foundation and rocking foundation, were applied to investigate the influence of the foundation type. In addition, a detailed three-dimensional finite element model was constructed to simulate an experimental case. The nonlinear material behavior including strain rate effects of concrete and steel reinforcement is included. The applicability and accuracy of the finite element model in simulating bridge pounding responses subjected to spatially varying ground motions are discussed. The experimental and numerical results demonstrate that non-uniform excitations and foundation rocking can affect the relative displacements and pounding responses significantly

Prescription audit of antihypertensive drugs used in stroke patients in a tertiary care teaching hospital

Background: Stroke is considered as one of the important reasons of death and disability worldwide. A rational use of medications is needed to prevent the recurrence and the disease related complications.Methods: The current study is a prospective observational study. All stroke cases, with patients above the age of 25 and treated with antihypertensive agents were included in the study. A total of 189 patients were found suitable for inclusion in the study. Using a suitably designed data collection form, all pertinent data such as patient demographics, prescribed medicines, drug interactions and adverse drug reactions were collected from the patient’s case file, nurses’ charts, and medication charts. Prescription pattern of antihypertensive drugs were obtained. The causality of the ADR was assessed using the Naranjo causality assessment scale and reported in the institution where the study was conducted.Results: Majority of patients included in the study were in the age group of 61-70 years. The incidence of stroke in this study was more in males than in the females. Ischemic stroke (72%) was more prevalent when compared to Hemorrhagic stroke. Among the antihypertensive agents, calcium channel blockers (32%) were the most commonly prescribed class of drugs. In our audit, drug related problems were observed in 27% of the cases which included cases with improper dose (3 cases), contraindications (4 cases), major drug interactions (20 cases), and adverse drug reactions (17 cases). Most of the prescriptions were legible. Drug related problems had a great impact on the overall stroketherapy.Conclusions: The drug related problems are a relevant aspect to be considered when treating patients with stroke and it can arise irrespective of adherence to guidelines

Health system’s readiness to provide cardiovascular, diabetes and chronic respiratory disease related services in Nepal: analysis using 2015 health facility survey

BACKGROUND: The burgeoning rise of non-communicable diseases (NCDs) is posing serious challenges in resource constrained health facilities of Nepal. The main objective of this study was to assess the readiness of health facilities for cardiovascular diseases (CVDs), diabetes and chronic respiratory diseases (CRDs) services in Nepal. METHODS: This study utilized data from the Nepal Health Facility Survey 2015. General readiness of 940 health facilities along with disease specific readiness for CVDs, diabetes, and CRDs were assessed using the Service Availability and Readiness Assessment manual of the World Health Organization. Health facilities were categorized into public and private facilities. RESULTS: Out of a total of 940 health facilities assessed, private facilities showed higher availability of items of general service readiness except for standard precautions for infection prevention, compared to public facilities. The multivariable adjusted regression coefficients for CVDs (β = 2.87, 95%CI: 2.42-3.39), diabetes (β =3.02, 95%CI: 2.03-4.49), and CRDs (β = 15.95, 95%CI: 4.61-55.13) at private facilities were higher than the public facilities. Health facilities located in the hills had a higher readiness index for CVDs (β = 1.99, 95%CI: 1.02-1.39). Service readiness for CVDs (β = 1.13, 95%CI: 1.04-1.23) and diabetes (β = 1.78, 95%CI: 1.23-2.59) were higher in the urban municipalities than in rural municipalities. Finally, disease-related services readiness index was sub-optimal with some degree of variation at the province level in Nepal. Compared to province 1, province 2 (β = 0.83, 95%CI: 0.73-0.95) had lower, and province 4 (β =1.24, 95%CI: 1.07-1.43) and province 5 (β =1.17, 95%CI: 1.02-1.34) had higher readiness index for CVDs. CONCLUSION: This study found sub-optimal readiness of services related to three NCDs at the public facilities in Nepal. Compared to public facilities, private facilities showed higher readiness scores for CVDs, diabetes, and CRDs. There is an urgent need for policy reform to improve the health services for NCDs, particularly in public facilities

On the effectiveness of rotational friction hinge damper to control responses of multi-span simply supported bridge to non-uniform ground motions

Base isolation techniques have been extensively used to improve the seismic performance of the bridge structures. The decoupling of the bridge decks from the piers and abutments using rubber isolator could result in significant reduction in seismic forces transmitted to the bridge substructures. However, the isolation devices could also increase the deck displacement and thus enhance the possibility of pounding and unseating damage of bridge decks. Moreover, previous investigations have shown that pounding and unseating damages on isolated bridges exacerbate due to the spatial variation in earthquake ground motions. Recent earthquakes revealed that isolation bearing could also be damaged due to the excessive movements of decks during large earthquake events. This study proposes the use of rotational friction hinge dampers to mitigate the damages that could be induced by large displacement of bridge decks, particularly focusing on pounding and unseating damages and bearing damages. The device is capable of providing large hysteretic damping and the cost of installing the devices is relatively economical. This article presents numerical investigations on the effectiveness of these devices on a typical Nepalese simply supported bridge subjected to spatially varying ground motions. The results indicate that rotational friction hinge dampers are very effective in mitigating the relative displacement and pounding force, as well as controlling the bearing deformation and pier drift. It is also revealed that the effectiveness of the device is not significantly affected by small changes in the slip forces; thus, small variations in the optimum slip forces during the lifetime of the bridge do not warrant any adjustment or replacement of the device

Seismic response analysis of multiple-frame bridges with unseating restrainers considering ground motion spatial variation and SSI

Unseating damages of bridge decks have been observed in many previous major earthquakes due to large relative displacement exceeding the available seat length. Steel cable restrainers are often used to limit such relative displacements. Present restrainer design methods are based on the relative displacements caused by the different dynamic characteristics of adjacent bridge structures. However, the relative displacements in bridge structures are not only caused by different dynamic characteristics of adjacent bridge segments. Recent studies indicated that differential ground motions at supports of bridge piers and Soil Structure Interaction (SSI) could have a significant influence on the relative displacement of adjacent bridge components. Thus the present design methods could significantly underestimate the relative displacement responses of the adjacent bridge components and the stiffness of the restrainers required to limit these displacements. None of the previous investigations considered the effects of spatially varying ground motions in evaluating the adequacy of the restrainers design methods. Moreover, the code recommendation of adjusting the fundamental frequencies of adjacent bridge structures close to each other to mitigate relative displacement induced damages is developed based on the uniform ground motion assumption. Investigations on its effectiveness to mitigate the relative displacement induced damages on the bridge structures subjected to spatially varying ground motion and SSI are made. This paper discusses the effects of spatially varying ground motions and SSI on the responses of the multiple-frame bridges with unseating restrainers through inelastic bridge response analysis