This paper solves the strip packing problem (SPP) that consists in packing a set of circular objects into a rectangle of fixed width and unlimited length. The objective is to minimize the length of the rectangle that will contain all the objects such that no object overlaps another one. The proposed algorithm uses a look-ahead method combined with beam search and a restarting strategy. The particularity of this algorithm is that it can achieve good results quickly (faster than other known methods and algorithms) even when the number of objects is large. The results obtained on well-known benchmark instances from the literature show that the algorithm improves a lot of best known solutions.