L ttr , : L = 45 , ttr = 1,2 .
:
4 :
B = b (I) + 2 ttr + (1012) = 25 + 2×1,2 + (1012) = 37,439,4 ;
b (I) : b (I) = 25 (. . 4.5.3).
4 :
B ≥ A 0, / L = 1714/45 = 38,08 .
B = 39 ( 10 ).
: A = B × L = 39×45 = 1755 2.
:
1 =0,5(B (b (I) + 2 ttr)) = 0,5×(39 (25 + 2×1,2)) = 5,8 ;
2 = 0,5(L h (I)) = 0,5×(45 33,8) = 5,6 .
: ;
.
:
1: 1 = 5,8 ; ;
2: , 3 ( 3 ).
c 2/ b (I) < 0,5, .
c 2/ b (I) = 5,6/25 = 0,224 < 0,5,
3: , 4 ( 4 ).
.
: hw = h (I) 2 t (I)= 33,8 2×1,25 = 31,3 ,
t (I) ; t (I) = 1,25 .
: bef = (b (I) d (I))/2 = (25 0,95)/2 = 12,03 .
:
m = hw / bef = 31,3/12,03 = 2,60 > 2. m > 2, a = 0,125.
M3 = as(bf)2 = 0,125×0,996×12,032 = 18,00 ×.
, : Mmax = max{M1; M2; M3} = 3 = 18,00 ×.
: .
t0 = 2,2 c ( ).
4.7.4.