To the best of my knowledge, if you double the cross sectional area of a wire you double the maximum weight it can support before breaking. But what if you use two wires of the original cross sectional area and tie them together? Can it still support twice the weight? Are there any new forces involved in this scenario?
Are you talking about tying them, like, summing their lengths? Then, definitely, no, it won't support double the weight.
Tensile stress is force divided by cross-sectional area. In this case, you're not increasing the area of the wire, just the length. So nothing changes? Well, something does: your wire will stretch more if its length is bigger.
So if you want to support double the weight and you have two equal wires, double the effective area by using two wires instead of one!