1.4.2 Formwork
Figure 7 : Pier Frame with Bogies
Generally , the formwork is made of plywood and timber beams . It is assembled onto the inferior part of transverse structures - steel trusses , which are suspended from transverse support beams on the level of the main girder .
All formwork panels are adjustable to the deck geometry . The formwork panels are opened and closed by rotation of the inferior metallic structure and consequently the formwork .
Each formwork panel has normally 8 suspension rods ( 2 in each of the 4 longitudinal alignments , half exterior to the deck webs and half interior to the deck webs ). The panel that surrounds the pier is usually different .
Each exterior rod is composed of two sections that are connected at mid-height during concreting and are disconnected when formwork and inferior part rotate for the launching stage . Interior rods have 3 parts and the middle one is disassembled during the launching stage and transported individually .
1.4.3 Transverse Structures
The superior part of the transverse structures is constituted by transverse vertical trusses ( which are connected to the main girder ) and a horizontal diaphragm joining adjacent vertical trusses that works like a platform . On the front part there is a system for rotation to accomplish the plan curvature of the bridge . The rotation is performed by means of two hydraulic jacks in each half of the transverse structures .
Figure 8 : Bogies – each bogie contains two lines of support for the two rails in each inferior chord of the girder
Lateral parts hang from the superior part and they are connected to the inferior part . They have several adjusting devices that allow changing the formwork position .
Inferior parts constitute a “ ground ” for the formwork . During concreting phase they are also supported by suspension bars ( rods ). Between the inferior parts and the formwork there are power screws and a grillage structure that allow for changing the longitudinal slope of the formwork .
The MSS is provided with locomotion winches and various hoists ( central , lateral etc .) for material transportation .
Figure 9 : Formwork ( red ) with suspension rods ( blue )
4 / 2017