The insolvent German construction group Walter Bau said Tuesday that parts of its operations are to be bought by Austrian rival Strabag for an undisclosed sum. A corresponding agreement was signed overnight Tuesday by Walter Bau's administrator, Werner Schneider, and Strabag chief Hans Peter Haselsteiner, Walter Bau said in a statement. The Austrian builder would take over the newly created Dywidag Holding which comprises four Walter Bau subsidiaries, including its Austrian unit and the road construction arm. Walter Bau, Germany's fourth-biggest builder, filed for bankruptcy protection at the beginning of this month, after failing to secure financing from its creditors. Walter Bau, based in Augsburg in southern Germany, said it was filing for insolvency in a last ditch attempt to save the company.