How to check the verticality of High rise building?

Hi!
All , I am totally new to the forum. But i was really moved by the idea CE has come up with; to get in touch with Engineers all over the world. As a Engineer it feels really great to be a part of CE forum.
I am a Civil Engineer & I want to know how to check the verticality of high rise building? What are the instruments used? and every possible information that needs to be kept in mind during construction of high rise building.

Come on friends pour in..


Sham

The conventional and widely used method is "Tie a small object to a thread and suspend it free from top". The thread will indicate absolute vertical direction ! Won't it ?

Agreed.....theorotically.
But this won't affect small constructions, I guess..

Friendz thanks for ur valuable info but as i am supposed to deliver a lecture on checking verticality of high rise bldg's i think i wll require some more information with precise theory.

Regards.
Sham

They obtain the angle of inclination (using an inclinometer) of the building at a known distance from the base and use trigonometry (its a right triangle ) to obtain its height if thats what u want???

I'm sure that it's late for your lecture but it was your post that drove me in this forum. Several techniques can be involved and can be grouped mainly into two as geodetic and non-geodetic techniques. The geodetic methods that can be used are levelling instrument, total station or theodolites (terrestrial survey), Global Positioning System (GPS), etc.

I’m not exactly familiar with the non-geodetic methods. Of course I’ve heard about tiltmeters. There are a lot of materials in Internet if you’re interested. The combination of geodetic and non-geodetic techniques are preferred but it depends on the specific type of the structure.
The check of the verticality of high-rise buildings is a part of deformation monitoring. The main difference between the two already mentioned methods is that when using non-geodetic techniques the results are relative (only the scalar part of the value can be achieved) and when using geodetic techniques the results are the so called “absolute”. I’m not sure about the tiltmeters and what they actually do but I intend to acquire more information.

the best method, i suppose is to use a laser beam.
Prakash.

Hi
You can download the following free patient for checking the verticality of high rise building.
Hope this can help you

Relating to the determination of verticality in tall buildings and other structures - Patent 5841353

The plumb bob is the most commonly used tool for monitoring the verticality of a building under construction. Two plumb bobs at at the end of each face of a building, Extending up to a fixed height from the base of the tower, so that same reference points are used at all time, can give the best result. Using the plumb bob i could complete the construction of a 80m tall rectangular structure at a cement plant, within the specified tolerance of H/1000 with ease.

Alternatively total station also can be used for monitoring the Northing & Easting of the four corner of the building at each level.To achieve this four reference pillars / fixed station are to be established on the ground away from the tower, from where the corners of the building can be viewed thro the telescope of total station till the building reaches its total height.

If it is possible to instal permanently, the laser plumb can be used for measuring the deviation. The tranmiter is to be fixed at the base and the target glass plate is to be attached to the moving form work permanently.
This method is used in the construction of circular silos / Chimneys wherein the slip form method is used for raising the RCC tower.

For the affordable GPS may handy with proper integration. I am yet to try this, no idea about limitation & cost.

I hope the above is of some use.

2010Mayan

Is using GPS practicable? Some times it may be possible to use GPS to obtain the coordinates of top of the building but how to use GPS to obtain bottom coordinates of the same line. Building will cover half of the satellite constellation and GDOP will not be acceptable.

We used a method to check the verticality of Bank Of Ceylon building in Colombo, Sri lanka. I will let you know, in few days time,the method we used.

hi.. i think to check verticality of a building, we can use theodolite and apply the trigonometric principles. its called trigonometric levelling.. if you want more precisely, you can do it with total station. its easy to operate and gives accurate values. that's how we found out the height of a signal tower in our surveying labs..

We can’t get a accurate value but we can get most probable value by doing many observations.