Influence of Non-Structural Elements on Dynamic Response of Multi-Storey Rc Building to Mining Shock
In the paper the results of calculations of the dy namic response of a multi-storey reinforced concrete buil ding to a strong mining shock originated from the main region of min ing activity in Poland (i.e. the Legnica-Glogow Copper District) ar e p esented. The representative time histories of accelerations regi st red in three directions were used as ground motion data in calcu lations of the dynamic response of the structure. Two variants of a numerical model were applied: the model including only structural e lements of the building and the model including both structural an d non-structural elements (i.e. partition walls and ventilation duct s made of brick). It turned out that non-structural elements of multi-st orey RC buildings have a small impact of about 10 % on natural freque ncies of these structures. It was also proved that the dynamic res pon e of building to mining shock obtained in case of inclusion of al l non-structural elements in the numerical model is about 20 % small er than in case of consideration of structural elements only. The p rincipal stresses obtained in calculations of dynamic response of mul ti-storey building to strong mining shock are situated on the level of about 30% of values obtained from static analysis (dead load). Keywords—Dynamic characteristics of buildings, mining shocks , dynamic response of buildings, non-structural eleme nts
Dynamic surface effects of underground copper ore mining in the Legnica Copper District, Poland
Abstract In the region close to Legnica, Poland, copper ore is mined at a depth of about 900 m by the process of explored chambers collapsing as a consequence of controlled explosions. These explosions generate underground shocks which propagate to the surface as seismic waves. This paper discusses the characteristics of these waves, their propagation through the rock mass, the vibrations they cause at the ground surface and their effect on certain structures at the surface. Some data on seismic energy are presented and discussed, including cases of medium and maximum energy, up to 1010J. Surface vibrations above the explored ore layers are analysed using the spectral amplitude – frequency approach. The correlation between source energy and measured magnitude is discussed, together with surface effects, in terms of existing MCS and MSK scales. A method for evaluating the degree of potential damage to structures caused by the vibrations is presented; this involves computational analysis in accordance with physical load models determined from measurements and simplified scales of vibration (SWD). Structural engineering designs for withstanding these paraseismic influences in these areas are also mentioned.
Fault Diagnosis and CAN Bus/Ethernet Redundancy Design of a Monitoring and Control System
The ship monitoring system is used to monitor and control the working status of various equipment on the ship. The navigational safety of the ship is affected directly by the stable working of the monitoring system. In this paper, a ship monitoring system with fault-type judgment function and bus redundancy is designed to improve system reliability and reduce fault checking cost. A redundant Ethernet/CAN bus communication network is constructed in the system, which connects multiple simulation nodes. The simulation node can simulate the faults that may occur during the communication process and feeds back the fault information to the host computer. The host computer will analyze and display the corresponding fault type on the user interface with the feedback information is received. The system reconfigures the network route autonomously when the simulation node has a communication fault. Routing of fault nodes can be switched to redundant routing, and the load balancing of the communication network can be maintained. Through experimental tests, the system can accurately locate faults and achieve fast switching of redundant routes between buses. Hence, the reliability of data transmission is improved.