A Discussion of Power Plant Loads and Load Combinations

摘要

This paper focuses on the design of steel support structures within electrical power generating facilities (power plants) which burn fossil fuels to generate electricity. The design of power plant structures requires the determination of loads, some of which will already be familiar to any practicing structural engineer, and some of which are specific to power plant structures. This paper provides guidance to the structural engineer for developing the various loads for power plants, and for combining these loads to determine the overall design loads. The discussion will be based around the use of Minimum Design Loads for Buildings and Other Structures, ASCE 7-10. (Note: where specific text from ASCE 7-10 is quoted or cited in this paper, it is with permission from ASCE.) Many of the loads involved in the design of power plant structures are the same as those encountered in the design of any typical building or structure, such as dead load, live load, snow load, wind load, and earthquake load. However, for each of these loads there are characteristics which are specific to power plants, and these are discussed in this paper. In addition, the design of a power plant structure involves loads which are not specifically discussed in ASCE 7-10. Examples of these loads include ash load, unbalanced pressure forces, forces due to thermal expansion and contraction of high-temperature equipment and ductwork, and boiler loads. The characteristics of these loads are discussed. The basic allowable strength design (ASD) load combinations found in ASCE 7-10 are expanded to include the additional primary loads specific to power plants. Finally, considerations for developing factored load combinations with power plant loads, for use with load-and-resistance-factor design (LRFD) methods, are discussed.