贝雷架钢便桥计算书30米跨

=57.43kN(3)28b#工字钢(工字钢根数42根)47.888×42×4.2×10/1000=84.474kN(4)贝雷架自重荷载(贝雷架自重340kg/m,共计60片)340×60×10/1000=204kN恒载计算75.36+57.43+84.474=421.27kN则均布荷载q4=421.27/30=14.04kN/m支点反力为Ra5=421.27/2=210.63kN跨中弯矩M9=0.125qL2=0.125×14.04×30×30=1579.75kN·m图11贝雷架恒载均布力、剪力及弯矩图则恒载弯矩M10(组合系数1.2)M10=1.2×1579.75=1895.69kN·m5.3.2活载计算根据公路I级车道荷载的均布荷载标准值qk=10.5kN/m,桥涵计算跨径小于或等于5m时,Pk=180kN;桥涵计算跨径等于或大于50m时,Pk=360kN,桥涵计算跨径大于5m,小于50m时,Pk值采用内插法求得,经计算集中荷载Pk=280kN。(1)均布荷载q=10.5kN/m跨中弯矩M11=0.125qL2=0.125×10.5×30×30=1181.25kN·m图12贝雷架活载均布力、剪力及弯矩图(2)集中荷载Pk跨中弯矩M12=0.25PL=0.25×280×30=2100kN·m图13贝雷架活载集中力、剪力及弯矩图Ra6=(10.5×30+280)÷2=297.5kN则活载弯矩M12(组合系数1.4)M13=1.4×(1181.25+2100)=4593.75kN·m5.3.3受力计算M14=M10+M13=1895.69+4593.75=6489.44kN·m由表1桁架结构容许内力表,得三排单层加强型贝雷架容许弯矩为4809KN·m,则M14<[M]=4809×2=9618kN·mQ7=Q5+Q6=Ra5+Ra6=210.63+297.5=508.13kN