**Krzysztof Skrzypkowski**

Faculty of Mining and Geoengineering, AGH University of Science and Technology, Mickiewicza 30 av., 30-059 Kraków, Poland; skrzypko@agh.edu.pl; Tel.: +481-2617-2160

Received: 8 September 2020; Accepted: 10 October 2020; Published: 12 October 2020

**Abstract:** In the article, comparative laboratory strength tests of three-point and four-point wooden cribs models are presented. In the case of cribs with a triangular cross-section, the notches made at an angle of 60 degrees were used for the first time. The individual beams of the three-point and four-point cribs were stacked horizontally and connected to each other by means of a quick-drying adhesive. The main aim of the research was to compare the empty models with cribs filled with a gangue. In order to better understand the mechanism of behavior of models under loads, load-displacement and pressure-compressibility characteristics are presented. It was found that filling the three-point and four-point crib with gangue increases its maximal load several times compared to the empty cribs.

**Keywords:** wooden cribs; gangue; load-displacement characteristics; pressure-compressibility characteristics
