Before effective action could be taken to make a workable Long-term solution to Numerous questions need answering;
What's moving? Which way is that going? Cracking is a familiar issue that's traditionally solved with using studs using callipers or crack monitors. However, what if there's limited or difficult access into this crack? Imagine if the cracking demands close observation, possibly safety is a problem? In such situations it's 's now feasible to put in a "black box" The detectors enclosed are in a position to quantify to sub millimetre precision at predetermined periods, ten times per day, once every day, once per week. Data is then sent by GSM to some central server for reporting. For extreme situations it's possible with this kind of gear to have instant alarm - if you need to be aware of any surplus movement then you can obtain an email or text alert delivered direct to you immediately! Tilt/Plumb can be tracked using total channels to quantify easy offsets or by shooting reflectorless observations within the structure's height. Longer term monitoring jobs may require goals to be fixed to the arrangement. When subsidence is supposed level datums could be established and exact digital level observations decreased and compared. Again black box technologies very similar to that utilized for crack tracking may be used.
Case Study 1
During structure of this Eden Project microscopic defects in certain welds into the primary arches of those homes were discovered. To make certain that they introduced no structural danger the principal design & build contractor made a decision to perform a load evaluation by hanging water stuffed weights in the arches and track the corresponding motion. Prisms were fixed into the arches in appropriate locations in which the structural engineer calculated that the motion which should happen, as the arches were filled. Tracking was undertaken and downloaded into a notebook with custom made spreadsheets allowing instant analysis of their outcomes on site and therefore allowing the structural engineer to deal with the loading arrangement.
Case Study 2
This historical mining site in Cornwall has been regenerated following decades of neglect. Whilst work is completed the Architect is eager to make sure that among those site's important features doesn't move Architect asked a 1m rectangular grid on the wall be tracked for subsidence and plumb. Reflective goals have been sandpaper glued into the wall to form the grid. Prisms are adjusted to surrounding structures to allow a Leica Total Station to resect it's position before observing each goal. The information is downloaded into digital terrain modelling software with elevation altered to make a contoured altitude drawing to show any variants.
Case Study 3
Each dock would be independently eliminated whilst temporary drapes would encourage that the deck whilst the new piers were assembled. The customer necessary reassurance that any motion in the deck although the work was completed could be discovered and there would not be a danger to the workforce or public.
Survey columns were assembled and two high-end Leica TCRA 1800 robotic total stations were set with weather security. Generators were positioned in the right place to keep power to the tools. The 1800s were put to a constant monitoring manner 24 hours a day seven days a week for another 6 months, whilst each one the piers were substituted. The information collected was downloaded from GSM link to onsite computers to empower our surveyor to analyse the results and create daily reports. The machine was set to activate an alarm to email and text staff should any excess or abrupt movement to be detected.
Case Study 4
After a period of heavy rain, a stone face in a redundant quarry allowed for industrial growth has been showing signs of instability and a stabilisation alternative was demanded. Quite a few control factors were discovered on the stone face and reflectorless measurements were detected using a Total Station. A string of stereo digital photos were taken with a calibrated camera. The photos were subsequently processed and utilizing pixel recognition applications a 3 dimensional floor model made to help the advisors in designing a soil nail remedy. After work was finished and using a metal mesh covering the stone face photogrammetry wouldn't longer be appropriate to track the stone face. A Leica HD Scanner was subsequently used to take observations produce point clouds which may be compared with previous versions and variants reported with segments and isopachytes.