由以往的地震災害顯示，強震來襲時，結構發生嚴重損壞者大多為平面或立面不規則建築結構，主要原因在於這類建築結構於地震時常發生扭轉變形及應力集中現象。但隨著經濟不斷蓬勃發展，建築結構中不可避免會出現平面不規則性。台灣又位處環太平洋地震帶，這類平面不規則建築結構的耐震能力是否足以抵抗強震來襲，便成為一項十分值得探討的研究課題。 本論文針對平面不規則鋼筋混凝土建築結構，以凹角性及質量兩種六樓建築結構為例，先進行結構分析及配筋設計，再以側推分析法進行耐震能力評估，並分析比較不同偏心量、不同豎向力、不同梁斷面尺寸和不同柱斷面尺寸對平面不規則建築結構耐震能力之影響，藉以瞭解不同影響因子對此類建築結構耐震能力之影響，以及一般耐震能力評估模式在評估此類建築結構耐震能力之適用性。 研究結果顯示，不同偏心量及不同豎向力分佈對建築結構耐震能力分析結果會有不同程度之影響，耐震能力分析時宜慎選；另外，梁與柱斷面尺寸增加均可增加建築結構之耐震能力，但梁斷面尺寸增加會使建築結構之韌性容量減少，柱斷面尺寸增加則會增加建築結構之韌性容量。本論文之研究成果可供工程實務界及學術界參酌引用。 The disasters of previous earthquakes showed that most of the severe damages from the structures were happened to flat or irregular facade ones when the earthquake hit. The main cause was such structures often occur in seismic torsional deformation and stress concentration. However, it is unavoidable that the plane irregularities keep appearing in the structures of buildings under the rising economy. Furthermore, as Taiwan is located on the Pacific seismic zone, the capacity of flat irregular building structures when the earthquake strikes becomes a topic which is worthy of study. For the irregular plane reinforced concrete structures in this thesis, it takes the concave corners and quality two kinds of sixth floor building structure as an example. First, it conducts with the structural analysis and design, and then proceeds with pushover analysis for seismic capacity evaluation. At the same time, analyzing both the irregular seismic capacity and the impact, which are compared to different eccentricity and vertical force, different dimension of the beam cross-section and different cross-sectional dimensions of the planar column. In conclusion, the above process are in order to comprehend the influences for structural seismic capacity of different effect factors, as well as the general seismic capacity evaluation mode of assessing the applicability in such structural seismic capacity. According to the result of the study, different eccentricity and vertical force distribution on different structural seismic capacity analysis results leads to different degrees of impact. Hence, the seismic capacity analysis should be discreetly chosen. In addition, the extension of beam and column section may increase the seismic capacity of building structure. Nevertheless, the extension of the beam cross-section dimensions of toughness may decrease the capacity of building structures while the extension of the column section consolidated the toughness capacity of building structure. The results of this study are available for engineering practitioners and the academia as a reference.