Search results for "Ridge"

Effects of corrosion on a steel bowstring bridge in marine environment: A case-study of assessment and retrofit

2021

The case-study of a steel bowstring bridge set in a marine environment and highly damaged by corrosion is presented. The bridge was built in 2004 and was repainted for corrosion protection in 2010. Despite the recent construction and the maintenance interventions, many structural elements like hangers are highly damaged by corrosion with decreasing performance in terms of serviceability and ultimate limit states. A deep investigation was carried out in order to assess the bridge and to establish the necessary retrofit actions to be carried out in the near future. In-situ tests reveal the reduced performance of the original steel in terms of strength and corrosion protection, together with t…

Steel and composite tied-arch bridges: a conceptual approach to structural design

2021

The behaviour of tied-arch bridges with composite decks (bowstring bridges) is overly sensitive to the different choices made by the designer in the first phases of the conceptual approach, mainly in the design of the arch and the deck. The geometry of the arch shape, the design of the arch–tie joint and the construction sequence can significantly modify the global behaviour in terms of stress state and deformed configuration. After a general discussion on the different parameters affecting the behaviour of bowstring bridges with steel–concrete composite decks, the consequences of choices made in the conceptual design phases are discussed, analysing the effects of each choice on the global…

Simplified Procedure for Evaluating the Effects of Creep and Shrinkage on Prestressed Concrete Girder Bridges and the Application of European and Nor…

2013

The effects of time-dependent phenomena on concrete prestressed girder bridges are investigated. The study concerns the case of bridges built directly in their final configuration and that of bridges built by a sequence of stages in which geometry, restraints, and loads vary until the final configuration is achieved. An analytical approach based on the principles of aging linear viscoelasticity and the age-adjusted effective modulus method is followed. The paper has two aims: the first is to provide an efficient and simplified tool for the evaluation of the structural response in the early stages of design; the second is to compare the results of the analyses on actual cases of bridges when…

Polar organic marker compounds in PM2.5 aerosol from a mixed forest site in western Germany

2008

The molecular composition of PM2.5 (particulate matter with an aerodynamic diameter2.5 microm) aerosol samples collected during a very warm and dry 2003 summer period at a mixed forest site in Jülich, Germany, was determined by gas chromatography/mass spectrometry in an effort to evaluate photooxidation products of biogenic volatile organic compounds (BVOCs) and other markers for aerosol source characterization. Six major classes of compounds represented by twenty-four individual organic species were identified and measured, comprising tracers for biomass combustion, short-chain acids, fatty acids, sugars/sugar alcohols, and tracers for the photooxidation of isoprene and alpha-/beta-pinene.…

Users’ Preferences for Designing Spaces under Urban Bridges as Vital Urban Spaces

2018

Today’s fast-paced urbanization process has caused many problems in urban development. Therefore, urban space is slowly losing its nature and disappearing due to the speed of rapid urban development. Trying to keep up with the modern era’s prevalent epoch of roads and bridges, urban policies in Iran have focused on developing road networks in recent years. Thus numerous elevated structures, urban highways and bridges are used to connect the urban fabric of the country’s cities, enabling the smooth transition of traffic in its cities. Although many view urban highways merely as tools for mobility; it is true that they influence on urban structure and the communities that they interconnect. H…

Penalization and data reduction of auxiliary variables in survey sampling

2012

Survey sampling techniques are quite useful in a way to estimate population parameterssuch as the population total when the large dimensional auxiliary data setis available. This thesis deals with the estimation of population total in presenceof ill-conditioned large data set.In the first chapter, we give some basic definitions that will be used in thelater chapters. The Horvitz-Thompson estimator is defined as an estimator whichdoes not use auxiliary variables. Along with, calibration technique is defined toincorporate the auxiliary variables for sake of improvement in the estimation ofpopulation totals for a fixed sample size.The second chapter is a part of a review article about ridge re…

Bridges Baltimore 2015: Charmed by Mathematics in Charm City

2016

In 2015, the Bridges World Conference, the most significant annual international gathering to be held for exploring connections between mathematics and the arts, met in Baltimore, USA. The conference program included lectures by recognized scholars and artists, the world largest exhibition of mathematical art, thematic theatre performances, a poetry afternoon demonstrating how mathematics can interrelate with literature, and a short film festival as well as workshops organized by researchers, educators and artists. nonPeerReviewed

Smartphone-based bridge monitoring through vehicle-bridge interaction: analysis and experimental assessment

2022

AbstractIn this study, the results of a vast experimental campaign on the applicability of a smartphone-based technique for bridge monitoring are presented. Specifically, the vehicle–bridge interaction (VBI)-based approach is exploited as a cost-effective means to estimate the natural frequencies of bridges, with the final aim of possibly developing low-cost and diffused infrastructure monitoring system. The analysis is performed using a common hybrid vehicle, fully equipped with classical piezoelectric accelerometers and a smartphone MEMS accelerometer, to record its vertical accelerations while passing over the bridge. In this regard, the experimental campaign is carried out considering t…

STRUCTURAL AND ARCHITECTURAL DESIGN OF AN INTEGRAL STEEL FOOTBRIDGE

2011

The Essence Theory of Software Engineering – Large-Scale Classroom Experiences from 450+ Software Engineering BSc Students

2018

Software Engineering as an industry is highly diverse in terms of development methods and practices. Practitioners employ a myriad of methods and tend to further tailor them by e.g. omitting some practices or rules. This diversity in development methods poses a challenge for software engineering education, creating a gap between education and industry. General theories such as the Essence Theory of Software Engineering can help bridge this gap by presenting software engineering students with higher-level frameworks upon which to build an understanding of software engineering methods and practical project work. In this paper, we study Essence in an educational setting to evaluate its usefuln…