The thickness of the concrete precast units is 150 160mm for hollow units and 75 100mm for solid units.
Concrete floor on steel beams.
Reinforced concrete toppings are placed on the beams to connect units as can be seen in figure 11.
The design of the steel beams and their connections to the columns required careful consideration to control deflections and vibrations of the floor structure.
The steel girders between the columns are cambered 19 mm 3 4 in and the infill steel beams are cambered 45 mm 1 3.
Concrete placement on cambered steel beams is not a simple task.
It is estimated that 50 of multi storey steel framed buildings use precast concrete floors.
The depth of the steel beams was designed to be encased within the thickness of the composite timber floor planks.
This results in a floor structure similar to a concrete flat plate but does not have downward projecting beams.
The asymmetric steel beams have a wider bottom flange supporting the ends of the clt planks.
The mass provides a heat sink that absorbs heat during the day and then in combination with natural ventilation the heat is purged during the cooler night time.
Erection of steel beams.
Various prefabricated beam sections are available to be used in the construction multi storey steel frame structure.
This floor system is composed of hollow or solid precast concrete units placed on steel beams on which shear studs are welded.
The precast concrete floor unit is used to span between supporting steel beams as an alternative to in situ concrete and metal decking.
The floor framing plan in figure 5 depicts beam camber for both infill beams and girders.
Exposed concrete floors supported on steel beams and used to provide thermal mass provision of sufficient thermal mass is an important part of a low energy building solution.