What To Do If You Don't Have Construction Details/Drawings

[tamimieh]

We are planning to add a new story for an existing (30 years old Concrete/Masonry Building) and cut thru slabs to accommodate a new elevator/shaft.
Unfortunately, some of the engineering details/drawings were lost. We only have the drawings of the GF & FF but not the basement nor foundations.

Is there any way to "scan" the existing building to identify all members and details?

 

[Brad805]

You can have a 3D laser scan done. From that there is a variety of modeling tools one can use to create a 3D model to generate 2D plans, sections and elevations. This is getting more and more common as the scanner prices become more reasonable. That will help define the geometry, but then your designers will need to decide on what methods to determine the rebar used.

 

[tamimieh]

Thank you for your prompt response.

The 3D laser will be helpful to capture the above grade dimensions. However, to study if the building can handle the load of the new story, structural engineers will need to know more about building/concrete members.

Concrete compressive strength: can be obtained from coring
GPR can be used to give a sense of the steel reinforcement "density" and distribution, but also has limited "depth of investigation"

What about members below grade (dimensions, compressive S...etc)?

 

[Brad805]

About the only method for features below the surface involves some degree of digging. If it the building is on piles there are tools to help determine their depth once you expose the pile head. I suggest you hire a structural engineer and a geotech to go over the proposed addition. An experienced local geotech will have some ideas of the most common practices for the era and a structural engineer with years of experience should be able to examine the structure to determine the likely hood additional loads can be added in a cost effective manner. In many cases that preliminary investigation can be very helpful to move the process forward in a logical fashion. To create as-builts to the level you are contemplating is a major undertaking and at the end of this it may not be cost effective to add loads to the existing.

Another option is to look for alternates to create new foundations for the additional story. This all depends on the spans, architectural requirements, and site constraints.

If this is within in a permit area the local authority sometimes has copies of the original information.