Curso de Manejo de águas pluviais<<strong>br</strong> />Capítulo 5-<strong>Microdrenagem</strong><<strong>br</strong> />Engenheiro Plínio Tomaz 3 de agosto de 2012 pliniotomaz@uol.<strong>com</strong>.<strong>br</strong><<strong>br</strong> />Eo= 1 / {1+[( Sw/Sx)/(1+(Sw/Sx)/(T/W -1)) 2,67 -1 ]}<<strong>br</strong> />Eo= 1 / {1+[( 5,15)/(1+(5,15)/(4,17 -1)) 2,67 -1 ]} =0,70<<strong>br</strong> />Q=Qw/Eo= Qs/ (1-Eo)= 0,019/ (1-0,70)= 0,06m 3 /s<<strong>br</strong> />Qw= vazão na seção de rebaixo (m 3 /s). É o que queremos<<strong>br</strong> />Q= vazão na guia e sarjeta (m 3 /s)<<strong>br</strong> />Qs= capacidade da vazão na boca de lobo rebaixada (m 3 /s).<<strong>br</strong> />Eo= eficiência do engolimento= Qw/Q<<strong>br</strong> />5-42
Curso de Manejo de águas pluviais<<strong>br</strong> />Capítulo 5-<strong>Microdrenagem</strong><<strong>br</strong> />Engenheiro Plínio Tomaz 3 de agosto de 2012 pliniotomaz@uol.<strong>com</strong>.<strong>br</strong><<strong>br</strong> />5.23 DNIT, 2006<<strong>br</strong> />Conforme DNIT, 2006 temos a fórmula de Manning modificado por Izzard conforme Figura<<strong>br</strong> />(5.15) e Tabela (5.22).<<strong>br</strong> />Q= 0,376 x (Z / n) x y 8/3 x S 0,5<<strong>br</strong> />Sendo:<<strong>br</strong> />Q= vazão na sarjeta (m 3 /s)<<strong>br</strong> />Y= altura da água na sarjeta (m)<<strong>br</strong> />S= declividade longitudinal da sarjeta (m/m)<<strong>br</strong> />n= coeficiente de rugosidade de Manning<<strong>br</strong> />Z= recíproca da declividade transversal Z= tg (θ )<<strong>br</strong> />tg (θ )= T / y<<strong>br</strong> />T= y x Z<<strong>br</strong> />y/T= 1 / tg (θ)<<strong>br</strong> />Caso Z=12<<strong>br</strong> />y/T=Sx= 1/12=0,083m/m<<strong>br</strong> />Figura 5.23- Corte transversal de uma sarjeta mostrando o ângulo θ<<strong>br</strong> />Tabela 5.19- Vazão na sarjeta sendo a altura da água y=0,10m, declividade transversal 2% e<<strong>br</strong> />coeficiente de Manning n=0,013, Z=50.<<strong>br</strong> />S<<strong>br</strong> />(m/m)<<strong>br</strong> />Q<<strong>br</strong> />(m 3 /s)<<strong>br</strong> />0,005 0,22<<strong>br</strong> />0,010 0,31<<strong>br</strong> />0,015 0,38<<strong>br</strong> />0,020 0,44<<strong>br</strong> />0,025 0,49<<strong>br</strong> />0,030 0,54<<strong>br</strong> />0,035 0,58<<strong>br</strong> />0,040 0,62<<strong>br</strong> />0,045 0,66<<strong>br</strong> />0,050 0,69<<strong>br</strong> />0,055 0,73<<strong>br</strong> />0,060 0,76<<strong>br</strong> />0,065 0,79<<strong>br</strong> />0,070 0,82<<strong>br</strong> />0,075 0,85<<strong>br</strong> />0,080 0,88<<strong>br</strong> />0,085 0,91<<strong>br</strong> />0,090 0,93<<strong>br</strong> />0,095 0,96<<strong>br</strong> />0,100 0,98<<strong>br</strong> />0,105 1,01<<strong>br</strong> />0,110 1,03<<strong>br</strong> />5-43