How do semi-gravity walls differ from gravity walls?

Semi-gravity walls and gravity walls are two types of retaining structures with distinct characteristics. The correct answer highlights a key difference between these two wall types.

Semi-gravity walls are indeed designed to be smaller and utilize a combination of self-weight and other structural elements to resist lateral forces, such as soil pressure or water pressure. They typically incorporate some additional features—such as reinforcing elements or cantilevered sections—through which they achieve stability without relying solely on their mass.

In contrast, gravity walls primarily depend on their weight to resist the forces acting upon them. These walls are constructed from dense materials and are larger and heavier, making them suitable in settings where they can effectively counteract pressures without the need for additional support structures.

The other attributes of flexibility, reliance on self-weight, and temporary designs do not accurately define the primary distinctions between semi-gravity and gravity walls. Being smaller allows semi-gravity walls to fit into a variety of different site conditions while still effectively managing earth pressures. This characteristic makes semi-gravity walls versatile, especially in areas where space or material usage is a concern.