• Home
  • Download PDF
  • Order CD-ROM
  • Order in Print
WATERFRONT  SURVEYS - 14071_226
OFFSHORE LOCATION BY TRIANGULATION

Engineering Aid 2 - Intermediate Structural engineering guide book
Page Navigation
  206    207    208    209    210  211  212    213    214    215    216  
convenient shore base to triangulate offshore distances from a line.  No  matter  how  you  get  offshore distances,  however,  offshore  points  cannot  be  marked like ground points with hubs or stakes. Therefore, in the  location  of  offshore  points,  there  must  usually  be coordination between a survey party on the beach and a  party  afloat. OFFSHORE LOCATION BY CHAINING Figure 10-28 shows a situation in which offshore locations  of  piles  for  a  wharf  were  determined  by chaining.  We  will  call  each  series  of  consecutive  piles running  offshore  a  line  and  each  series  running parallel to the shore a row. Alignment for each line was obtained by transit—set up on a shore base line offset from the inboard row of piles. In each line the distance  from  one  pile  to  the  next  was  chained,  as shown. In  figure  10-28  the  lines  are  perpendicular  to  the base line, which means that the angle turned from the base line was 90° and the distance from one transit setup  to  the  next  was  the  same  as  the  prescribed distance   between   lines.   If   the   lines   were   not perpendicular  to  the  base  line,  both  the  angle  turned from the base line, the distance from one transit setup to the next, and the distance from the base line to the first  offshore  pile  in  each  line  would  have  to  be determined. Consider  figure  10-29,  for  example.  Here  the angle between each line and the base line (either as prescribed  or  as  measured  by  protractor  on  a  plan)  is 60°40´.  You  can  determine  the  distance  between transit setups by solving the triangle  JAB for AB, JA being drawn from transit setup B perpendicular  to  the Figure  10-29.—Offshore  location  in  line  oblique  to  the  base line. Figure 10-28.—Offshore location by chaining 10-27







Western Governors University

Privacy Statement
Press Release
Contact

© Copyright Integrated Publishing, Inc.. All Rights Reserved. Design by Strategico.