Istanbul is located in an earthquake-prone region, and it is expected that a part of the existing structures will collapse under the expected earthquake forces. Reinforced concrete construction is the common method of structural design and construction for buildings in Türkiye. Estimation of the mass and volume of debris resulting from the collapse of reinforced concrete buildings is crucial for post-earthquake search and rescue operations, debris removal, and the reconstruction process. As a part of the search and rescue and reconstruction efforts, an assessment for the state of the roadway networks after the earthquake is necessary. This study presents an analytical method for estimating the mass, volume and the possible spread of debris that may result from the collapse of a reinforced concrete building. The proposed method is based on a simplified analytical approach developed from the general structural characteristics of such buildings. The method provides an important tool for estimating the debris quantity at the neighbourhood and district levels, allowing for the assessment of the probability of road blockages and network damage. Using the method presented in this study, it will be possible to gain an insight into the amount of debris on the roadway network and the potential for road closures. The ability to forecast the impact of debris on the roadway network can help plan emergency response and rescue operations. A case study will be conducted on the road network of an urban area with a high earthquake damage risk in Istanbul, assessing the potential impact of expected destruction on the road infrastructure using fractal analysis and network theory.