Author: Dixon, J C;Prior, M J
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Dixon, J C;Prior, M J
The Structural Engineer, Volume 72, Issue 22, 1994
Foundations near trees What is deemed appropriate when building near trees is producing more comments. Brian Pyle refers us to damage occurring even in areas implied to be deep enough to be stable in the NHBC recommendations. He also provides other warnings: The paper on NHBC Standards published on 16 August may encourage a greater use of the guidelines in the design of foundations. The experience of our practice dictates a need for caution in respect of the following: Zone of influence. A typical experience of damage from tree roots is from a 20m-high oak tree, 20m from the corner of a Victorian property with a cellar. Significant clay shrinkage on a medium plasticity soil had been experienced at the depth of the foundations to the cellar 2.5m below ground level at the distance of 20m. This is way outside the guide graphs. Differential subsidence had created a crack width of nearly 20mm, at roof level, which almost closed during periods of very wet weather. We advocate the use of the term ‘differential subsidence’. It explains precisely what has occurred (Verulam 16 August). Verulam
Electronic products are becoming more sophisticated in their functionality. In parallel, the customer is rightly demanding reliability performance far in excess of anything seen previously. This makes the role of the design assurance team an increasingly important one. This fact is illustrated by reference to the activities of the design assurance group at GEC-Marconi Research Centre. Highlighted are the extremes of design configuration for which structural and thermal performance need to be predicted -from a satellite ground station to a solder joint. A.T. Humphrey and D.J. Burrows
In my recent article ‘Problems of working without a contract’ (16 August ,1994) I outlined some of the ways in which an engineer might get paid even where he has no contract with whoever has instructed him. I considered two situations: -Where a client asks for a preliminary appraisal ‘to be provided within 7 days’ and the engineer says he may or may not be able to comply with this timetable (although in fact does), no fees are discussed and the client then refuses to pay. Generally the engineer can recover a reasonable sum for work done (on a quantum meruit valued on an objective basis). - Where an engineer is invited to tender, and does so, but for some reason the client fails to consider his tender, although he considers others. Traditionally the engineer here has no remedy, but it was noted that recent case law suggests otherwise, particularly where the client is a public body and has failed to consider the tender at all (as opposed to considering it inadequately). Ian R. Yule