Portal Method of Structural Analysis

The portal method of structural analysis is a simplified approach used to analyze the behavior of low-rise buildings under lateral loads. It is based on the assumption that the building's lateral load-resisting system acts like a portal frame, consisting of two vertical columns connected by a horizontal beam at the top.

Analysis of Low-Rise Buildings

Low-rise buildings typically have a height that is within the range of one to four stories. They are generally characterized by their simple and uniform structural systems, which make them suitable for analysis using the portal method.

Uniform Framing

Low-rise buildings with uniform framing have a consistent structural system throughout the building. This means that the members, such as columns and beams, have the same properties (e.g., size, shape, and material) and are arranged in a regular pattern. The uniformity of the framing system allows for an accurate application of the portal method.

Nonuniform Framing

On the other hand, low-rise buildings with nonuniform framing have variations in their structural systems. This could include changes in member sizes, shapes, or materials, as well as irregular arrangements of members. The presence of nonuniform framing makes it difficult to apply the portal method accurately, as the assumptions underlying the method may not hold true.

Selection of Correct Answer

Based on the given options, the correct answer is option 'B' - low-rise buildings. This is because the portal method of structural analysis is generally suitable for low-rise buildings due to their simple and uniform structural systems. The assumptions made in the portal method align well with the characteristics of low-rise buildings and allow for a reasonably accurate analysis of their behavior under lateral loads.

It is important to note that the suitability of the portal method may vary depending on the specific design and characteristics of the low-rise building in question. In some cases, more advanced analysis methods may be required to account for complex structural systems or unusual load patterns.