3.2 Load Effect Combination
3.2.1 The fundamental combination of load effect shall meet the following requirements:
1 Inaddition to the current national standards Load Code for the Design of Building Structures GB 50009 and Code for Seismic Design of Buildings GB 50011，the fundamental combination of load effects on the structure of main building shall comply with this code as well.
2 When the structure of the main building is analyzed as a whole structure to determine the size of main girder（or column），the fundamental combination of load effects shall not include temporary loads resulting from transportation and lifting of large equipment during construction and installation.These temporary loads shall be accommodated by taking temporary measures.During construction and installation，the bearing capacity of individual members may be checked with their safety grade lowered by one grade.
3 When the structure of the main building is analyzed as a whole structure to determine the size of main girder（or column），the variable loads of equipment（piping）under abnormal operating conditions may be excluded from the fundamental combinations of load effect.However，these variable loads shall be considered in calculation of structural members and their connections，with the combination value coefficient being taken as 1.0.But the safety grade of the structural members shall not be lowered.
3.2.2 The partial safety factor for the fundamental combinations of load effects shall be determined according to the current industry standard Technical Code for the Design of Civil Structure of Fossilfired Power Plant DL 5022.
3.2.3 The accidental load effect combinations for the structure of main building shall be determined based on the actual situation of project and the provisions in the current national standard Load Code for the Design of Building Structures GB 50009，and shall comply with the following requirements:
1 Accidental explosion load of pulverized coal bunker and other potential explosion loads，such as gas explosion load and vented explosion load of explosion vent，shall not be included in load effect combination in overall analysis of the structure of main building.But the bearing capacity of structural members shall be checked and relevant detail measures shall be taken.
2 Permanent loads，dynamic loads，and short-circuit moments shall be included in accidental combination for turbine-generator foundation.The combination value coefficients of dynamic loads and short-circuit moments can be respectively taken as 0.25 and 1.0.The permanent loads shall include the self-weight of equipment.
3 If combinations of postulated pipe rupture load and other loads in nuclear power plant are considered，the combination value coefficient may be taken as 1.0.
4 Tornado load shall not be combined with loads due to earthquake action，installation and maintenance，or other abnormal operating conditions，but may be combined only with the characteristic value of permanent loads and variable loads under normal operating conditions.The combination equation is as follows:
where，Sd——design value of load effects combination；
DK——characteristic value of permanent loads；
LK——characteristic value of variable loads under normal operating conditions，including equipment（piping）loads and live loads on floor；
WtK——characteristic value of tornado loads，which shall be calculated according to 7.4.5 of this code.
3.2.4 For characteristic combination，frequent combination and quasi-permanent combination，the load effects combination shall be determined according to the current national standard Load Code for the Design of Building Structures GB 50009，but the coefficients of combination value coefficient，quasi-permanent value coefficient and frequent value coefficient of variable loads shall be determined according to this code.
3.2.5 The thermal action calculation for structures or members and its combination with other load effects shall comply with the current national standard Load Code for the Design of Building Structures GB 50009.