A structural engineer or architect with experience in this type of work is the place to start. Call around and ask if they have done this type of work and ask for references. Call the references. Make sure they have done something similar. This is pretty specialized work. The professional will be able to advise you as to how he sees the repair taking place and what contractors http://bestbeton.netne.net you will need. Have the professional inspect the work before you make final payment so you can be sure it was done per his directions. That way if something goes wrong or the repair doesn't work, you can look to the professional as well as the contractor for relief.