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Duties of the Rodman

Engineering Aid 3 - Beginning Structural engineering guide book
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LEVEL   PARTY   ORGANIZATION, EQUIPMENT,  AND  FIELD PROCEDURES Certain   basic   preparations   relative   to   the magnitude  and  complexity  of  the  job  must  be performed  before  any  leveling  survey  is  under- taken. Proper planning and thorough identifica- tion  of  the  procedures  to  be  followed  in  all phases of the work are essential to the success of the  leveling  operation.  Participating  in  this preparatory  work  will  also  enhance  the  experience and increase the capabilities of the crew members. Some  of  the  preparations  you  must  be  familiar wit h are discussed in the next several paragraphs. LEVEL  PARTY  ORGANIZATION The  size  of  your  leveling  party  will  depend upon  such  variables  as  the  order  of  accuracy required  and  the  number  of  experienced  personnel available.   Ordinarily,   the   smallest   crew   may consist  of  two  individuals:  an  instrumentman and  a  rodman.  To  improve  the  efficiency  of  the leveling   operations,   additional   personnel   are required.  The  addition  of  a  second  rodman  to alternate  on  backlights  (BSs)  and  foresights  (FSs) will speed up leveling. If you add a recorder, the instrumentman  will  be  able  to  take  readings  as soon  as  the  rodmen  are  in  position.  In  surveys requiring a shaded instrument, an umbrellaman is required. Duties of the Instrumentman An instrumentman, or levelman, runs the level and  makes  adjustments  required  for  proper  opera- tion.  He  makes  certain  that  no  stations  are omitted,  that  turning  points  (TPs)  are  properly selected, and that BMs are properly established and  identified.  The  levelman  is  usually  designated by the EA1 or EAC to act as the chief of the party. When a two-man leveling party uses a self-reading rod, the levelman is also the recorder. However, if a target rod is used, the rodman usually acts as  the  recorder.  A  good  levelman  keeps  within  the required  limits  of  error. As  chief  of  the  party,  you  must  be  alert  to recognize  common  problems  encountered  in  the field and be able and ready to solve them using the   best   solution.   Your   sound   judgment   and proper  course  of  action  in  handling  these  field problems  will  influence  the  quality  of  your  survey and  the  meeting  of  your  survey  schedules. Handling Leveling Instruments and Equipments Leveling  instruments,  as  well  as  all  surveying instruments  and  equipments,  have  to  be  accorded the  care  and  proper  handling  that  any  delicate instrument  merits.  Give  special  attention  to prevent sudden shocks, jolts, and bumps, which will   cause   retesting   of   the   instrument   to   be required.  A  damaged  or  disturbed  scientific instrument, however minor, will adversely affect correct  and  accurate  results.  As  a  rule,  a  visual inspection  for  signs  of  physical  damage  of  the instrument  is  to  be  conducted  before  each  use. An engineer’s level is a precision instrument containing   many   delicate   and   fragile   parts. Movable parts should, when not locked in place, work  easily  and  smoothly.  When  a  part  resists movement, there is something wrong; if you force the part to move, you are quite likely to damage the  instrument.  You  will  also  cause  damage  by wear  if  you  use  excessive  force  in  tightening clamps  and  the  like. To ensure easy movement, keep threads and bearing  surfaces  on  movable  parts  lubricated.  For the  same  reasons,  these  parts  have  to  be  kept clean. Always clean the parts before oiling them. When oiling the parts, use only fine instrument oil;  and  do  not  use  too  much  of  it.  An  excess  of oil  gathers  dust  and  also  thickens,  which  will interfere  with  free  movement  of  the  parts.  This is  especially  true  in  cold  weather  because  low temperatures cause oil to congeal. In cold weather, graphite  powder  is  a  more  suitable  lubricant  than oil. Keep the level in its case when it is not in use and when you are transporting it to and from the jobsite.  The  level  screws  and  the  clamp  screws should  be  tightened  just  enough  to  prevent  motion of the parts inside the case. The instrument case is designed to reduce the effect of jarring and is strongly made and well padded to protect the level from  damage.  When  transporting  the  level  by vehicle, you should place the carrying case about midway between the front and rear wheels. This is the point at which the bouncing of the wheels has  the  minimum  effect. Never lift the instrument out of the carrying case  by  grasping  the  telescope;  wrenching  the telescope in this manner could damage a number of delicate parts. Always lift the instrument out of the case by grasping the footplate or the level bar. When the instrument and the tripod are to be carried  from  one  setup  point  to  another,  loosen 14-5







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