Hambro® MD2000 Design Info Specifications Typical Details Installation Guide

The Hambro^® MD2000 Floor System combines composite joists with poured concrete developing a hybrid concrete / steel T-beam running in one direction and an integrated, continuous slab in the opposite direction. The MD2000 System utilizes permanent metal decking.

The bottom chord (min. Fy 50psi) acts as a tension member during both the concreting stage and the service life. The web system, consisting of bent rods, (min. Fy 44psi) ties the top and bottom chords together and resists the vertical shears in the conventional truss manner.

Hambro^® MD2000's patented 13 gauge S-shaped top chord section (min. Fy 50psi) has four basic functions:

1. It is the compression member of the joist during the non-composite concreting stage. The system is not typically propped.
2. It is a “high chair” for the welded wire mesh, developing negative moment capacity in the concrete slab where it is required over the joist top chord.
3. It supports the slab forming system
4. It automatically becomes a continuous shear connector for the composite stage.

The concrete slab is reinforced with welded wire mesh at the required locations and behaves structurally as a continuous one-way reinforced concrete slab.

The permanent metal decking, when locked into the MD2000 top chord section, not only acts as form for placing concrete, but provides the essential lateral and torsional stability to the entire floor system during the concreting stage.

The interaction between the concrete slab and Hambro^® joist begins to occur once the wet concrete begins to set. The necessary composite interaction for construction loads is achieved once the concrete strength, f’c reaches 500 psi (3.5 MPa). This will usually occur within 24 hours.

Even in the coldest of winter concrete pouring conditions, construction heating will maintain the concrete at temperatures necessary for this strength gain. When in doubt, concrete test cylinders can be used to verify strength.