A finite element model for the analysis of a beat-up process is investigated. One of the main purposes of the analysis is to find the beat-up force required to obtain a plain weave of some given density. The proposed weave model includes one warp and two of the most recently inserted wefts. The warp is considered to be elastic while the wefts are assumed to be rigid in the present model. We applied our method to interpret the possible reason of a special type of abnormal structure frequently found in weaving practices, where uneven pickspacing repeats itself periodically. Results from sample calculations suggest a possibility that the special type of the uneven pickspacings can happen even under perfect machine conditions.