CHAPTER II. 



Commencement of works, or opening up Importance of well-considered temporary 

 works Alexandra Dock, Hull Portsmouth Dockyard Extension Southamp- 

 ton Tidnl Dock. 



THE course to be pursued in opening up the works of a large 

 dock scheme, particularly if the site is on an exposed foreshore, 

 requires special care and attention, in order, not only that 

 some portion of the permanent work may be commenced with 

 the least possible delay, but that all subsequent portions taken 

 in hand may follow in regular order in accordance with a pre- 

 arranged plan without calling for extensive, and therefore costly, 

 alterations in the disposition of the temporary works and plant. 

 In fact, in commencing a work, no part requires more anxious 

 care in the conception of, or skill in the carrying out, than 

 the temporary works which have frequently to be of a very 

 substantial character and the disposition of plant. Upon a 

 just appreciation of these all-important points will depend in 

 a very great measure the success of the work, both from an 

 engineering and a contractor's point of view. 



The following particulars are abridged from accounts of the 

 preliminary course pursued on some of the most important 

 modern dock works. 



Alexandra Dock, Hull. 1 The site of this dock comprised 192 

 acres on the foreshore of the Humber, where the range of tide 

 equals 22 feet 6 inches. Of this area 152 acres were below 

 high-water mark, and extended considerably below low-water 

 mark. To reclaim this total area, an embankment 40 feet high 

 and 6000 feet long was required to surround it. 



As the permanent works could not be delayed until the 

 completion of the permanent reclamation embankment, tem- 

 porary embankments were formed to exclude the water from 

 the site of the works in sections. The banks first taken in 

 1 M.r.I.C.E., xcii. p. 145. 



