BEST METHOD FOR HIGH RISE CONSTRUCTION - GPS? ZENITH/VERTICAL OPTICAL PLUMMET? RESECTION
Greetings from Malta.
To those out there who had an experience of high rise construction, i would like to share some of your advice for the young generations.
I am a qualified 28 year old land surveyor working with a construction company in Malta.
I will be involved for construction of a high rise construction project and it will consist of 4 towers of different floor levels. The height tower is 21 floors from the road. You need to keep into consideration that the facade will be constructed with glass material thus the accuracy should be within its tolerance when setting out the edge of concrete slab and also the lift should be kept vertically straight against deflection. As you can see from the development model, the construction is straight forward.
This is the first experience that I am going to get involved on such a big project and thus I need some professional advises to make a proper decision.
Attached are some pictures of the project for a better idea and also the location of the site from google map. You can type on google maps/search: Mriehel Gasan and you will find the exact site location.
I am not sure which method I am going to use for this project. After an intensive research I have not yet made my mind up for the best land surveying practices method for a high rise building do carry out the setting out of points and transfer the datum levels on each floor in terms of accuracy and precision and time efficiency.
- Using Zenith Laser Optical Plummet as per below instruments? Using this zenith optical plummet means that we must leave a vertical hole on each slab from the very bottom basement levels till the complete of construction. Am I correct?
- GNSS method would be better, easy, more accurate and faster? I thought to use GS16 as a rover while I can connect with free of charge base reference station from Government Mapping Department. It is free because it was funded by the EU so it is public. Do you think this system will achieve its accuracy standard? I guess using an RTK system mounting the rover on the total station (smart total station) since setting out of hundreds of points with total station is faster (since laser helps a lot to guide the laborer to put nails). I saw a lot of surveyors in Dubai using GNSS system for high rise construction. What do you suggest?
Since there will be 1 crew (1 land surveyor which is me and 1 assistant/laborer) assigned on this project, do you think that using GPS is faster? Or still believe with the optical plummet? I have the feeling that the process of using the software spider or any other kings of software's is a long process because every time I do the setup and after starting the antenna to receive the signals, then I have to go all the way down the stairs to my mobile office do run the software, then back again near the gps/smart total station to commence the setting out. Am I right?
The purpose of the spider software is to adjust the control points to use the post processing method? I thought maybe I could use the RTK system.
- The other method is resection. Let’s say I get a permission from the owners to install some ten 360 prisms on the building roofs so that I can use resection method. With total station I can setup and observe 4 stations which is orientation with resection by installing several 360 prisms on the top of the building when the construction reach its certain height levels but I am not sure the it will achieve its top accuracy with resection despite these prisms will be located away from the site about 300 meters or more. My question is about the accuracy and efficiency because I think for these 10 stations, somehow I need to carry out a traverse observations to adjust these stations.
- Or maybe other method that I missed or product that I might not be aware yet?
I am really looking forward to hear from you guys. Thanks for your time and interest.