Seismic Pounding of Bridges due to Multi-Support Excitation with traveling wave

Abstract: -Among structural damages, seismic induced pounding has been commonly observed in severalearthquakes. When lateral and transverse movement of a structure occurs during earthquakes, it will hit adjacent structure and bounce back. This back and forth hitting of adjacent structures is known as pounding. The earthquake ground motion is usually assumed as uniform dynamic motion in seismic analysis. This assumption may be inadequate for structures placed at large areas like bridge, dam etc. Pounding in bridges is a result of the relative movement of the adjacent bridge superstructures at the expansion joints. This movement depends on different structural dynamic properties of the adjacent spans and characteristics of ground motions at the pier supports along the bridge. This paper includes a study of effect of pounding between bridge superstructures under the action of earthquake motion having multi-support excitation with traveling effect. The present study is a numerical investigation of pounding effect on a simply supported bridge using finite element method, using the software, OpenSees

Finite Element Buckling Analysis Of Stiffened Plates

Abstract:-Structures consisting of thin plates stiffened by a system of ribs have found wide application for aircraft, ships, bridges, and buildings as well as in many other branches of contemporary structural engineering. Buckling analysis can be used to find critical compressive loads at which a structure becomes elastically unstable. In this paper, buckling analysis of stiffened plates was carried out using finite element software NISA. The analytical investigations of stiffened plates are rarely found in literature; hence it is found apt to carryout such investigations to provide design recommendations

Impact on postpartum hemorrhage of prophylactic administration of oxytocin 10 IU via Uniject™ by peripheral health care providers at home births: design of a community-based cluster-randomized trial.

BACKGROUND: Hemorrhage is the leading direct cause of maternal death globally. While oxytocin is the drug of choice for postpartum hemorrhage prevention, its use has generally been limited to health facilities. This trial assesses the effectiveness, safety, and feasibility of expanding the use of prophylactic intramuscular oxytocin to peripheral health care providers at home births in four predominantly rural districts in central Ghana. METHODS: This study is designed as a community-based cluster-randomized trial in which Community Health Officers are randomized to provide (or not provide) an injection of oxytocin 10 IU via the Uniject™ injection system within one minute of delivery of the baby to women who request their presence at home at the onset of labor. The primary aim is to determine if administration of prophylactic oxytocin via Uniject™ by this cadre will reduce the risk of postpartum hemorrhage by 50 % relative to deliveries which do not receive the prophylactic intervention. Postpartum hemorrhage is examined under three sequential definitions: 1) blood loss ≥500 ml (BL); 2) treatment for bleeding (TX) and/or BL; 3) hospital referral for bleeding and/or TX and/or BL. Secondary outcomes address safety and feasibility of the intervention and include adverse maternal and fetal outcomes and logistical concerns regarding assistance at home births and the storage and handling of oxytocin, respectively. DISCUSSION: Results from this trial will build evidence for the effectiveness of expanding the delivery of this established prophylactic intervention to peripheral settings. Complementary data on safety and logistical issues related to this intervention will assist policymakers in low-income countries in selecting both the best uterotonic and service delivery strategy for postpartum hemorrhage prevention. Results of this trial are expected in mid-2013. The trial is registered at ClinicalTrials.gov: NCT01108289