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Issue 23/24

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The Structural Engineer
The Structural Engineer
The Structural Engineer
The Structural Engineer
The Structural Engineer
The Structural Engineer
The Structural Engineer
The Structural Engineer

The approach to shear enhancement at short shear spans for members without designed links in EN 1992 has been changed since early drafts. The revised rule works well for cases with single point loads but a number of problems have been identified for cases with multiple or distributed loads. For these, the rule appears to be over-conservative and difficult to use. It is proposed that the shear enhancement rules in EN 1992 are not applicable for the design of members with multiple loads or design for envelopes of load cases and that alternative rules should be provided. The proposed rules are based on the approach adopted in previous drafts of EN 1992. They have effectively been introduced in the UK EN 1992-2 (bridges) National Annex and could possibly also be used in other structures. The rules for short shear span enhancement in members with designed links suffer from many of the same problems but in addition are over-conservative, often more conservative than the normal rules. It appears that the resistance provided by the links to the shear at short shear spans was originally meant to be used in combination with a concrete contribution to the resistance but the current approach has no concrete contribution. It is proposed that this change should be reversed. There are two other ways of getting short shear span enhancement for members with designed links in EN 1992. Strut and tie analysis gives good consistent results but can be difficult to use for many cases. The other method is to use the rule that allows the links in an increment to be designed for the minimum shear in the increment. This rule needs clarification and modification as the restrictions on its use are unclear. It also appears to be over-generous for inclined links but this is being corrected by an editorial change. Paul Jackson, BSc, PhD, CEng, FIStructE, FICE Technical Director, Gifford Stephen Salim, BEng, PhD Engineer, Scott Wilson, Formerly Gifford Jon Shave, MEng, MA, PhD, CEng, MICE Principal Engineer, Parsons Brinckerhoff Steve Denton, BA, PhD, CEng, MICE Technical Director, Parsons Brinckerhoff

The Structural Engineer
The Structural Engineer
The Structural Engineer

Design is a major factor in economic success and in improving the quality of life for society. To assess the current position of design within the built environment this paper presents the results obtained from a suite of questionnaires. The questionnaires were sent to clients, practitioners, graduates, academics and students representing the main stakeholders, in the supply of design services and projects, within the industry. A total of 828 people, mainly civil and structural engineers, completed the questionnaires representing a large number of organisations and universities within the UK. The general conclusion is that higher education currently prepares graduates adequately for detailed well-defined design activities but does not provide them with the required skills to understand and undertake the holistic design process. The main criticism is that the educational programmes are not linked to the ‘real world’. Further, there is a requirement to improve the interface between practitioner and client within the design development process. The response from the clients also highlighted that there is room for improvement in the quality of designs and in the methods of assessing both the design service and completed projects. C. G. Bailey, BEng, PhD, CEng, MIStructE, FICE, MIFireE K. A. L. Johnson, BSc (Eng), CEng, FICE T. Alonso, BSc, MSc, PhD M. A. Orzechowski, BSc, PhD All at the School of Mechanical, Aerospace and Civil Engineering, The University of Manchester

The Structural Engineer

As the the Institution of Civil Engineers celebrates the birth of Thomas Telford and the Institution of Structural Engineers celebrates its own centenary, engineers might be forgiven for overlooking another significant anniversary: 2007 is the bicentenary of a remarkable scientific publication which set out much of the structural theory modern engineers rely on today in their daily work: Thomas Young’s A Course of Lectures on Natural Philosophy and Mechanical Arts. Alasdair N. Beal, BSc, CEng, MICE, FIStructE Thomasons LLP

The Structural Engineer
The Structural Engineer