You can roughly judge based on the abutment protection type and span. Early block stone abutments can be gravity-type or light-weight. Generally speaking, the abutment protection is an eight-shaped or one-shaped wall. And if the span is less than or equal to 8 meters, it can basically be judged as a light abutment. If the abutment protection is a cone slope or the span is greater than 8 meters, it is basically a gravity type.