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Predictive Likelihood Paper Published

12 January, 2010 (16:20) | General | No comments

In a good start to the new year, the paper The use of predictive likelihood to estimate the distribution of extreme bridge traffic load effect has been published in Structural Safety. It was first submitted in December 2007 so it’s great that it has been given page numbers at last! It has been published in Vol. 32(2) March 2010 issue of Structural Safety, pages 138-144.

Even though it’s been a long wait, Structural Safety is a well-reputed journal with an impact factor of 1.47 (2009) which is very high for a civil-engineering journal. The paper is available here, but may require a purchase if you don’t have an institutional login:

http://dx.doi.org/10.1016/j.strusafe.2009.09.001

Abstract
To assess the safety of an existing bridge, the loads to which it may be subject in its lifetime are required. Statistical analysis is used to extrapolate a sample of load effect values from the simulation period to the required design period. Complex statistical methods are often used and the end result is usually a single value of characteristic load effect. Such a deterministic result is at odds with the underlying stochastic nature of the problem. In this paper, predictive likelihood is shown to be a method by which the distribution of the lifetime extreme load effect may be determined. An estimate of the distribution of lifetime maximum load effect facilitates the reliability approach to bridge assessment. Results are presented for some cases of bridge loading, compared to a return period approach and significant differences identified. The implications for the assessment of existing bridges are discussed.

The full reference is:

Caprani, C.C., OBrien, E.J. (2010), ‘The Use of Predictive Likelihood to Estimate the Distribution of Extreme Bridge Traffic Load Effect’, Structural Safety, Vol. 32(2), March, pp. 138-144. http://dx.doi.org/10.1016/j.strusafe.2009.09.001.

IStructE Structural Awards 2009

14 October, 2009 (17:27) | General | No comments

The Institution of Structural Engineers‘ Supreme Award for Structural Engineering Excellence has been award to Expedition Engineering for their design of the Infinity Footbridge in Stockton-on-Tees, UK, at this year’s Structural Awards, held on Friday 9 October. You can read more about this structure here.

Infinity Footbridge

Infinity Footbridge, Expedition Engineering Ltd.

The other awards are outlined here and are all fascinating examples of structural design.

If you are a student on an accredited civil/structural engineering programme, you should join the IStructE – it’s free! Click here to join.

At last – an excuse…

8 October, 2009 (20:44) | General | 1 comment

As you can see from the very scientific graph below, it is only natural that lecturers have a bad sense of humour!

BSOH

BSOH

DIT Final Year Projects 2009/10

21 September, 2009 (10:24) | General | 2 comments

Around this time of year, many students have difficulty trying to identify appropriate topics for study towards their Final Year Project. Many other third level colleges stipulate the available projects to work on but we do not do this in DIT. For the weaker students this creates a difficulty, whilst for the stronger students this allows them to work on a topic of most personal interest. So there are pros and cons, but such is life.

In any case, and perhaps to avoid repeating myself, below is a list of topics that may be of interest, some ideas more developed than others. Also note that some may be more difficult than others. Please contact me if you are interested in pursuing any one of these projects.

Ultra High Performance Fibre-Reinforced Concrete (UHPFRC)

This material is quite new and has been used in some sample projects  on the continent. It remains to be calibrated for Irish cement. The proportion of steel or synthetic   be match tot he chemical composition of our cement, as well as our aggregate. In doing so it is important to maintain certain properties of the concrete, such as strain hardening rates. This material has particular applications in bridge rehabilitation. The student will be required to assimilate information from various European research institutions/sources.

Influence Surfaces Applied to Bridge Traffic Load Effect

The two-dimensional version of the influence line, influence surfaces allow great flexibility in determining the load effects of interests for any position of a vehicle on the bridge. The student here will develop an appropriate algorithm for calculation. They will use finite element analysis of several representative bridge decks and lengths to find the influence surfaces for load effects of interest. They will then use generated traffic streams to calculate the load effects which can be compared to traditional results obtained from influence lines and lane factors.

Valve Influence in Tuned Liquid Column Dampers (TLCDs)

The amount that a valve is open or closed affects the properties of a TLCD. Whilst there are some standard ways of establishing the valve’s influence, this project will examine, both experimentally and theoretically, this effect. The experimental apparatus and computer code from a final year project carried out in 2008/9 should be of assistance.

Calibration of Traffic Microsimulation Model

Perhaps more suited for those on the Civil Engineering degree, this project will attempt to calibrate a recently-developed traffic micro-simulation model to more established models. This will require the understanding of traffic flow and the influence of various parameters on the micro and macro properties of traffic flow.

Effect of Lane Closure on Bridge Traffic Loading

This project will use a traffic micro-simulation model to investigate the effect that a lane closure has on bridge traffic load effect. It will examine the influence of input flow rates and the location of the lane closure in relation to bridge, for example.

Prestressed FRP for Strengthening RC Beams

A recent European project develop the idea of prestressing FRP strips prior to gluing to the soffit of an RC beam that is to be strengthened. This project will develop a theoretical model and validate it using experiments. It will conclude on the influence of the prestressing, and the additional strength gained.

Damage Detection using Distributed Accelerometers

This project will use the results from an array of accelerometers attached to a beam, which is then excited, to identify any damage in the beam. It will have both theoretical and experimental aspects. In particular the results of the analysis of the accelerometer data before and after damage has been introduced into the experimental and theoretical beams.

Digital Image Processing for Vibration Monitoring

This project will examine the use of digital footage (using a standard camcorder) of a vibrating structure to determine the structural properties. Image processing will be done using the Matlab Image Processing toolbox. If the method is found successful it offers a cheap alternative to traditional structural monitoring devices.

IStructE Lecture: Wexford Opera House

13 May, 2009 (20:52) | Engineering | 6 comments

10299_5_wexford2big

The rebuilding of Wexford Opera House, the first purpose-designed opera house in Ireland was
completed on schedule for the 2008 autumn opera festival. The new opera house has been
constructed in the town centre on the site of the old Theatre Royal, contains two theatres of
differing scales. The principal auditorium accommodates 780 seats, whilst a new adaptable
auditorium of 175 seats provides for performance in a variety of formats.

Arup Consulting Engineers were the Civil, Structural and Geotechnical Engineers on the
development will describe how this steel framed building was designed and constructed. The
highly complex geometry of the steel frame, including curved fronted auditorium balconies, was
assembled in 6 phases working out from the most landlocked corner of the site.

This talk will be presented by Cian Ó Donnchadha, Chartered Engineer, Arup Consulting Engineers.

6.30 pm Tuesday 19th May 2009, Room 259, DIT, Bolton Street, Dublin 1

(Tea/ coffee reception at 6.00pm in the College). All welcome.

See the flyer here.

wexford-opera-house-model1

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