How does HZP140 bridge construction crane to install girders and cross piers?

HZP140 segment assembly bridge construction crane is specifically developed by ZZHZ and MBEC of China, featuring installing full span box girder segment, combining with the feature of prestressed concrete beam of Yellow River Bridge in Taohuayu, Henan, China. It is prevailing to use prefabricated segment assembly bridge construction crane to construct elevated highways overseas and in Hong Kong and Macao, but the construction technology above mentioned is firstly adopted in Henan, China.

segmental assembly bridge girder launcher

The bridge construction crane is mainly made up of main girder, launching nose, front support, rear support leg, auxiliary front support, auxiliary rear support, lifting trolley, 10t overhead crane and transverse luffing mechanism.

(1). Install girders

After finishing installing the bridge construction crane, firstly vertical positioning, relative position of front support and main girder is unchanged, when the span reduces, rear support moves forward to make its centre line coincide with pier centre line. Then lateral positioning of the crane based on bridge centre line, make the complete machine symmetrical.

The bridge construction crane uses construction way of full span segment girder hanging, front support and rear support of the bridge construction crane bears all external force at working.

Steps to install girders:

1. Girder transporter feeds girders under the bridge,

2. Lifting trolleys firstly lift pier base girder, put them on the pier temporary support and hang on the main girder;

3. Lift precast girder segments respectively from pier to the midspan and hang them on the main girder,

4. Finally lift antepenultimate girder,

5. Roughly adjust the elevation one by one backwards, then finely tune the elevation. 6. Then the segment takes off the main girder, painted epoxy resin motar, after accurate positioning, make a temporary pre-stressed tension, finally stretch-draw permanent pre-stressing tendons,

7. Lifting oil cylinder of front, rear support jacks the bridge construction crane to make the complete machine descend 200mm, force conversion between boom and pier is completed, remove slings and boom, the installing girders is finished.

(2) Longitudinal movement to cross piers

Steps to cross piers:

1. Lifting cylinders of front support and rear support fall back, main girder of the bridge construction crane drops on their roller wheel boxes,

2. Remove the connections between lifting cylinders and main structure, start hydraulic longitudinal movement mechanism, move forwards 23.9m by oil cylinder lifting;

3. Auxiliary front support reaches front pier, its cylinder stretches out and support on the pier top, cylinder of front support jacks main girder corbel up to 300mm,

4. Install temporary support, draw back cylinder of front support, temporary support bears the force,

5. Start hydraulic longitudinal movement mechanism of the front support, move forwards to front pier and anchor it,

6. Draw back the cylinder of front auxiliary support, cylinder of rear auxiliary support stretches out and bears force,

7. When the rear support takes back, its upper part and bottom part separate,

a. upper part of rear support moves forward 5.5m, lifting trolleys move bottom part to pier top ahead, and anchor it,

b. then move upper part to pier top ahead, connect it with the bottom part,

8. Remove temporary support with lifting trolleys, auxiliary rear support takes back, start longitudinal movement cylinders of front, rear support, jack the complete the machine to move forwards about 27.1m, finish crossing girders

Transverse movement flange position is obligate on the front, rear support of the bridge construction crane, which can push main frame to move laterally on the main girder of support and realize the complete machine to shift between left bridge and right bridge.

Main girder of HZP140 segment assembly bridge construction crane is of superposition box girder structure, featuring high stiffness and low deflection. Main structure adopts symmetrical design principle, can make a two-way construction and adapt to two working conditions: feeding girders under the bridge or at rear parts of the bridge, is a new-style bridge construction equipment in present segment assembly bridge construction cranes.