SE Segment Erector

Segment Erector (SE) is being used to install Precast Segment for Balance cantilever bridge when the used of mobile crane is not feasible.

a. SE provides these advantages

1. Setting up only one time for each pier. This is a very crucial feature. In urban area the Balance Cantilever Bridge normally is a part of the larger project; and it serves as a solution for crossing the existing highways where longer spans are needed. Installation activity

above the existing highway might not be smooth. In many cases very short time frame will be given for each day. Or in some cases only certain day in a week would be granted for work. SE is always in the ready mode therefore will fully utilize the given few hours of construction time frame

2. Construction across highway is unpredictable. In many cases the construction duration will be longer than expected, SE cost is not affected by the construction duration if the contractor owns it

3. SE utilizes variety of segment delivery solutions for difficult terrain

4. SE has good re-sell value and is easy to store

b. Various Types

There are 3 types of Segment Erector, each provide different solution for the segment delivery.

1. One that could lift all segment near to pier, relocate and install segment to the cantilever tips.

2. One that could lift all the segment from the opposite cantilever tip, relocate and install the segment to the other tip.

3. A fixed type which can Lift the segment from the tip and install the segment on the same location without having segment relocation ability.

Derrick Crane

A Derrick Crane is considered as a fixed model Segment Erector. The advantages of Derrick Crane are its ability to swing the Segments from side to side which is sometimes an important feature that is needed under certain conditions.

SE can be relocated in few major parts and become operational within 5 days. Dismantle and relocation normally takes 2 days and electrical connection take 3 days.

c. Moving Mechanism

All Segment Erector can be running on Metal Wheel with metal track or running on pneumatic tire. The fixed model will utilize hydraulic cylinder for its advancing.

The model running on pneumatic tire will have extra self-weight. Therefore it is very important to clarify with the bridge designer the allowable weight of Segment Erector before ordering. In some cases extra post tensioning is needed to accommodate the additional weight from the SE.

d. Segment Feeding

Photo below shows the sequence of a segment being lifted and fed into the center of a SE. This is the SE that could lift the segment from one side and install the segment on the other tip. After segment is secured inside the SE it could be delivered to other tip for installation.