A clamp assembly is provided for securing a panel or fairing to an I-beam, and comprises a pair of side blocks and a clamping block, together with a single bolt to secure them in place. Each of the side blocks as an inclined wedge surface, and the T-shaped clamping block has similarly sloped wedge surfaces along the sides of the leg of the T. When a bolt this passed through side legs of the side blocks, and through or under the clamping block, a sliding and wedging action between the inclined and sloped wedge surfaces occurs. Moreover, a clamping action between the top surface of the clamping block and the lower surface of the lower flanges of the I-beam is also induced.