"横向支撑结构" can be translated as "lateral (or transverse) bracing structure" in English.
"Lateral" or "transverse" both convey the meaning of being across or at right angles to the main direction or axis, which is appropriate for describing a structure that provides support in a horizontal direction perpendicular to the main load-bearing elements.
"Bracing structure" refers to a framework or assembly designed to provide stability and resist lateral forces.
Therefore, "lateral bracing structure" or "transverse bracing structure" are both suitable translations for "横向支撑结构".