An elbow clamp assembly structurally supports or replaces a connection between a main pipe and an elbow pipe. The elbow clamp assembly includes an upper clamp body and a lower clamp body securable on opposite sides of the main pipe in facing relation. The upper and lower clamp bodies are connected by a clamp bolt extendable through the main pipe. An elbow boss is securable to the elbow pipe, and a cross bolt is extendable through the elbow pipe and connected between the elbow boss and the clamp bolt.