7 research outputs found
Kwietnica okazała Protaetia speciosissima (Scopoli, 1786) (Coleoptera: Scarabaeidae) w skrzynce lęgowej dla puszczyka Strix aluco L., 1758 w Dąbrowach Krotoszyńskich
<p>This paper presents a new record of the rose chafer Protaetia speciosissima (Scopoli, 1786) (Coleoptera: Scarabaeidae), a rare beetle species associated with tree hollows. Specimens of this beetle were found in the oak forest in the Krotoszyn Forest District, west-central Poland, in nest-box for the tawny owl (Strix aluco L., 1758) that had accumulated dead organic material. This finding suggests that it is possible for P. speciosissima to develop and reproduce outside its typical microhabitats.</p>
Research and TLS (LiDAR) Construction Diagnostics of Clay Brick Masonry Arched Stairs
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
Strength Parameters of Clay Brick Walls with Various Directions of Force
The study analyzes the anisotropy effect for ceramic masonry based on experimental tests of samples made of 25 × 12 × 6.5 cm3 solid brick elements with compressive strength fb = 44.1 MPa and cement mortar with compressive strength fm = 10.9 MPa. The samples were loaded in a single plane with a joint angle that varied from the horizontal plane. The load was applied in a vertical direction. The samples were loaded at angles of 90°, 67.5°, 45°, 22.5°, and 0° toward the bed joints. The most unfavourable cases were determined. It was observed that the anisotropy of the masonry significantly influences the load-bearing capacity of the walls depending on the angle of the compressive stresses trajectory. Approximation curves and equations for compressive strength, Young’s modulus, and Poisson’s coefficient were proposed. It was observed that Young’s modulus and Poisson’s ratio will also change depending on the trajectory of compressive stresses as a function of the joint angle. Experimental tests allowed to determine the failure mechanism in prepared specimens. The study allowed to estimate the masonry strength with the load acting at different angles toward the bed joints