The article deals with the mobility during crisis situations. In these situations, there is not always possible to use the roads or ways and the vehicles have to move on different areas, mostly on terrain like meadows, forests etc. That is why we should be able to evaluate whether the terrain is traffiacable or not, whether the vehicles mire or not. The approaches of evaluating the terrain traffiability are described here as well as the instruments used for these purposes, procedures of measuring and calculations. Another aim of this article is to apprise with the means for negotiation the low endurable terrain – traditional wooden and perspective mats.

The article deals with the selection of devices suitable for military engineers of the Czech Armed Forces from the devices used by the NATO armies’ engineers to provide mobility support. A multicriteria evaluation method was used to evaluate the technique. The evaluation of individual criteria was carried out by the officers of the 153 ^rd Engineer Battalion. The determination of the criteria and parameters of the required engineering devices was made on the basis of an analysis of the current state of the field of engineered support. These criteria and parameters were presented by the author in already published articles. This type of research is important due to the lack of mechanization means for obstacle breaching near the first line in the combat operation, and the lack of engineer´s means to support the violent crossing of the water barrier of the mechanized and engineer units.

The paper deals with the investigation of parameters and influences for the system of evaluating the trafficability of vehicles through the terrain. Trafficability is one of the main aspects to ensure the movement of own troops, which falls into the main task of the Engineer troops - combat and general engineering support for all types of activities and operations of the army. Trafficability is the ability of a vehicle to move in rough terrain or on damaged roads and depends on many factors. The most used tool for determining trafficability in the Czech Army is the penetrometer. It is the PT-45 penetrometer, which is described in the Žen 2-16 Military Roads and Ways and the main evaluation criterion is the weight of the vehicle. Within the framework of international cooperation, soldiers encounter the manual FM 5-430-00-1 Design and design of roads, airports and heliports during events on the battlefield - road design, which works with a cone penetrometer and evaluates the throughput of the vehicle based on other factors such as properties of tires, ground clearance, engine power, etc. Inaccurate or incorrect evaluation leads not only to a stop the engagement of individual vehicles, but the entire convoy, which in terms of the operational task stops the manoeuvre and may lead to failure of the order. Therefore, it is important to know what parameters and influences have a fundamental influence on the system of evaluating the trafficability of vehicles, whether it would not be appropriate to add other aspects that will lead to higher accuracy of measurement, or, conversely, to exclude some. In solving this task, the authors decided to use the above-mentioned manuals and their evaluation systems. The objectives of the paper were achieved by analysis and calculations of individual parameters listed in these regulations, which affect the trafficability through the terrain, so that the degree of dependence is determined. It was found that some parameters have a major impact on trafficability and it is necessary to take into account even a slight change in these values. In contrast, other parameters are negligible as a result. These calculations confirm the suitability of updating the evaluation system for the telescopic penetrometer PT-45 to determine the trafficability of vehicles, so that it is possible to obtain more accurate results of measured values of the Czech army in the performance of tasks.

Plastic spacers create a linear and systemic weakening of the structure. The extreme loading of the structure tests the structure itself to its load-bearing limit or even locally exceeds this limit, thus revealing all its weak points, which are the spacers. Nevertheless, the influence of the spacers is not included in the design calculation of the reinforced concrete element. In addition, products intended as spacers for the placement of reinforcement do not belong to the specific families of construction products covered by a harmonized standard of European parliament regulation. For these reasons, it is not required to demonstrate any characteristics of these products. This fact allows the use of arbitrary spacers’ shapes and materials. As shown by the experiment carried out, the use of commonly used plastic liners will result in a weakening of the cross-section. The normal assessment of the ultimate or serviceability limit state is not affected by this weakening. An example of an experiment carried out where this problem was captured is the subject of this paper. With Europe’s current deteriorated safety situation, understanding the influence of spacers in blast-loaded reinforced concrete structures on structural failure is important, and it is appropriate to further address this issue. Based on this experiment, it is not possible to accurately identify the causes of the explosion cracks. In order to determine with certainty the effect of spacers on the strength of the structure under abnormal blast loadings, research needs to focus on this area. In the field experimental measurements and numerical simulations, it was found that the use of linear spacers has an effect on crack formation under the blast action of the tested slab.

This article deals with the possibilities of terrain negotiation in extraordinary situations. In these situations the communications, appointed for this kind of movement, are not supposable to use. Then it is necessary to judge, whether the vehicles are able to go through the terrain or not. One of the parameter influences the trafficability is the tire. Especially it is the width and the outer diameter of the tire. Whether and how much the tires effect the trafficability is the topic of this article.