Guideway and Columns
The dimensions of the Scomi Rail monorail guideway are .8 meter (20.3") wide, 1.6mm (40.6") deep (at the midpoint,) and 2.2m (55.9") at the endpoints. Typical column size is 1.2m (30.5") x 1.6m (40.6") in size. The minimum curve radius is 70 meters (177.8',) and the maximum gradient on the mainline is 4%. Average beam length is 28m (71.1',) and the average beam weight is 100 metric tons. Some beams are up to 44m (111.8') in length and weigh 190 metric tons. Some of the beams are superelevated (banked) up to 12%. The tolerances are very tight, +/-3mm in cross section and +-8mm per 20m in length.
The Kuala Lumpur Monorail system includes 8.6km (4.14 mi) of twin guideway beams, 11 stations and 1 maintenance depot. More than 600 beams are being used in the system, each one unique. The beams are stitched together with concrete and post-tensioning to form continuous "frames" of beams consisting of two to five spans. There are 80 "frames" in the system.
Transportation and Erection
As you can see, special heavy-duty hydraulic multi-axle transporters are used to transport the beams from the casting yard to their final location in the city. Beams are lifted into place using two telescopic cranes each rated at 300 metric tons. Specially designed lifting brackets are used because the unique geometry and center of gravity of each beam. Temporary stabilizing towers are attached to the pre-cast "crosshead." Then the beams that will make up a frame are connected together with continuity pre-stressing. Finally, 800mm (3.15') sections are poured at each joint, completing a post-tensioned, continuous multi-beam structure.