Strengthening of existing Concrete slab with Steel beams and shear studs.

[prince samson]

Dear friends,

I'm in the process of strengthening an existing slab (built 1970) (17.5 MPa cube strength), with steel beams & shear studs to achieve a composite action which will reduce the span and reduce the slab bending moment. (pls refer attachment for better clarity). Have explored all other strengthening methods which have been ruled due to cost, time or constructability issue. Iam planning to design the beam as a composite beam with precast planks. Can you pls help me with a previous design calculation similar to this or can you please share any literatures or spreadsheets to solve this issue for me. Since all available literatures are for either metal deck composite beams or precast plank concrete composite beam. Not sure how to proceed on this one ..Thanks in advance ! !​

 

[HTURKAK]

Will you pls explain the concept of (composite beam with precast planks ) ?

Apparently, the slab is CIP having 200 mm thk. and almost nearly one way slab .. Adding three HEA 200 , will change the behavior to one way ( four )slabs in opposite direction and top reinf will be needed for the new developing hogging moments. What about the left side ? seems an RC wall ?..

If you provide more info . regarding the reinf. of the subject slab, the situation of the RC beam on the right and left side , you may get better responds.

 

[r13]

The basis of composite beam design is the same across all types of materials, or mix of materials - transform the slab geometry to conform to material property of the beam, then analyze as a homogenous beam. The problem of your situation is how to make the connections between the precast panel and the existing concrete slab, and does the existing beam (on the right) has adequate strength to support the increased demand. BTW, what is HEA?