Your browser is no longer supported

For the best possible experience using our website we recommend you upgrade to a newer version or another browser.

Your browser appears to have cookies disabled. For the best experience of this website, please enable cookies in your browser

We'll assume we have your consent to use cookies, for example so you won't need to log in each time you visit our site.
Learn more

Strutting arrangement


Strutting in the collapsed section was different to that being used on neighbouring cut and cover sections where the alignment was straighter.

On the straight sections NLC fixed struts at 4m centres to the 6m wide diaphragm wall panels. Struts were connected symmetrically to prevent uneven forces being applied. Asymmetrical wall panel loading would have introduced rotational moments that could have undermined the structure's integrity.

An alternating connection pattern was applied along each diaphragm wall: two struts were connected to the outer edges of one panel and a single strut to the centre of the next panel.

But the curved tunnel alignment near the TBM launch shaft forced a radial arrangement of struts. This disrupted the symmetry of the strut to panel connection pattern, and would have resulted in uneven loading of diaphragm wall panels.

A more fl exible strutting system was therefore designed, with struts connected to horizontal waling beams which spread loads over a larger area.

Strutting forces were to be further distributed by the installation of I-section spreaders, branching from the strut-ends at 45¦. Struts were supported midspan by king posts connected by longitudinal stringer beams.

Struts, waling beams and king posts were 400mm 2I-sections.

Have your say

You must sign in to make a comment

Please remember that the submission of any material is governed by our Terms and Conditions and by submitting material you confirm your agreement to these Terms and Conditions. Please note comments made online may also be published in the print edition of New Civil Engineer. Links may be included in your comments but HTML is not permitted.