1.1 Actions and effects on structure 。Actions on structure Classification by action mode作用形式： ·Direct actions.直接作用：imposed in terms of"force'”,usually called"load'. ·eg structural self-weight,weight of assembly of persons,equipment,vehicle and so on ·Indirect actions间接作用：imposed in terms of“deformation", ·e.g foundation settlement causing external structural deformation,temperature change, ground movement due to earthquake 归东理王大军 SHANDONG UNIVERSITY OF TECHNOLOGY
1.1 Actions and effects on structure • Actions on structure ▫ Classification by action mode作用形式: Direct actions直接作用: imposed in terms of “force”, usually called “load”. e.g. structural self-weight, weight of assembly of persons, equipment, vehicle and so on Indirect actions间接作用: imposed in terms of “deformation”, e.g. foundation settlement causing external structural deformation, temperature change, ground movement due to earthquake
1.1 Actions and effects on structure Actions on structure Classification by action duration作用时间： ·Permanent actions永久作用：constant magnitude,negligible variation or monotonic variation to a limit ·e.g self-weight,earth pressure,hydrostatic pressure ·Variable actionsi可变作用：the magnitude varies during service period and the variation is NOT negligible. ·e.g live loads on floor,roof;wind load,snow load ·Accidental actions偶然作用：may not happen during service period,once happened: huge magnitude but short duration. ·eg seismic action,blasting force 归东理子大军 SHANDONG UNIVERSITY OF TECHNOLOGY
1.1 Actions and effects on structure • Actions on structure ▫ Classification by action duration作用时间: Permanent actions永久作用: constant magnitude, negligible variation or monotonic variation to a limit e.g. self-weight, earth pressure, hydrostatic pressure Variable actions可变作用: the magnitude varies during service period and the variation is NOT negligible. e.g. live loads on floor, roof; wind load, snow load Accidental actions偶然作用: may not happen during service period, once happened: huge magnitude but short duration. e.g. seismic action, blasting force