*Article* **Research and TLS (LiDAR) Construction Diagnostics of Clay Brick Masonry Arched Stairs**

**Rafał Nowak 1,\*, Tomasz Kania 2, Radosław Rutkowski <sup>3</sup> and Ewa Ekiert <sup>4</sup>**


**Abstract:** The study presents the terrestrial laser scanning (TLS) diagnostic of the clay brick masonry arched staircase in a historic building. Based on the measurements of the existing arched stair flights, 1:1 scale experimental models with and without stair treads were made. Strength tests of the models were carried out for different concentrated force locations in relation to the supporting structure. Force, deflections and reaction in the upper support of the run were measured during the tests. The influence of the masonry steps on the curved vault on the load capacity and stiffness of the run structure was analyzed. The conducted experimental investigations showed that the key element responsible for the actual load-bearing capacity and stiffness of this type of stair flights were the treads above the masonry arch.

**Keywords:** stairs; masonry; clay brick; arch; vault; management; quality; light detection and ranging (LiDAR); TLS
