What is the calculation condition for the 40/160 bridge girder launching gantry?
?1. Design technical conditions
launching gantry
Rated lifting capacity????????????? 160t
Utilization grade????????????????? U5
Load condition??????????????????? Q2
Complete machine working level??????? A5
Institutions working level????????????? M4
Trolley track gauge?????????????????? 6.0
Trolley lifting speed with full load?????? ?0.9m/min
Trolley moving speed with full load????? ?2.75m/min
Moving speed for the complete machine to cross piers??? ?2.75m/min
Max wind pressure in working condition???? 250N/m2
Max wind pressure in non-working condition ??????????????????????800N/m2
2. Safety factor and admissible casino spiele stress
Take load combination based on present national standard crane design code GB3811-83
Table 1????? material safety factor and admissible stress (MPa)
| material | Safety factor?n? | pull?press?bend??? | Shear force??? | Pressure-bearing??cd?? | |
| ?type load combination | Q235 |
1.33 |
177 | 102 | 265 |
| Q345 |
1.33 |
259 | 150 | 386 | |
| ?type load combination | Q235 |
1.15 |
205 | 118 | 308 |
| Q345 |
1.15 |
300 | 173 | 450 |
Note: if thickness of rimmed steel and structural steel > 15mm and thickness of steel plate > 20mm, the admissible stress should be multiplied by 0.95 to be reduced.
3. Allowable static deflection of bridge girder launcher frame [ f ]
Span L= 43m, middle span: [f]?43000/700?61.43mm
Span L= 30m, middle span: [f]?30/700?42.85mm
According to clause 3.8.1.1, crane design code GB3811-83, working level of bridge crane is A5 or below A5, YL?L/700;
