b h I 0 I b E c ( mm) (×10-2 m 4) (×10-2 m 4) (× 107kPa) BL1 300 700 0.8575 1.2863 3 BL2 300 700 0.8575 1.2863 3 ZL1 300 700 0.8575 1.7150 3 ZL2 300 700 0.8575 1.7150 3 BL1 300 700 0.8575 1.2863 3 ZL1 300 700 0.8575 1.7150 3 层 砼 b h ( mm) Ic E c ( × 107kPa) h ( m) 1 C30 700 700 2.00 3 5 2~4 C30 700 700 2.00 3 3.3 5 C30 700 700 2.00 3 3.3 1 根数 K = i bj/i C a c=( 0.5+K ) / ( 2 +K ) D =a c· 12i c/h