12.7 The lateral force that is generated during building shaking can be calculated with the equation: Force = mass x acceleration, Based on this, which one of the following statement(s) is correct? ⚫ A building's total seismic design force is proportional to its weight. ⚫ Seismic forces are applied at the ground level; therefore, a building's upper floors have very small seismic force. ⚫ The largest seismic force is generated at the upper floors where they have the highest acceleration. . Seismic protective devises that dampen (reduce) building acceleration may be used to reduce the building seismic force. 12.8 Given five-story building, that weighs a 100kips and has concrete shear walls and special moment-resisting frames: a) Determine Response Modification Factor, R, from ASCE 7, Table 12.2-1 for Dual System of Special Moment Frame and Special reinforced concrete shear wall (Type D-3) b) Calculate Seismic Base Shear (V) using the following ASCE 7 equations and building information: SDS V = C₂W where C. is the lesser of Cs (R/1) and Cs SD1-1 T. R Accelerations (USGS maps): SDs = 1.1 Sp1 = 0.6 Building Period: T= 0.5 sec Importance Factor: le = 1.0 (commercial building) c) The architect has decided to eliminate the moment frames because the deep beams along the building perimeter reduce window openings. Determine the percent increase in base shear if the moment frames were eliminated and lateral resistance was provided with only a special reinforced concrete shear wall system (Type B-4 in ASCE Table 12.2-1)