The column in this photo has a base plate which has been welded to it using a fillet weld by a fabrication company. The base plate has four holes which have been drilled through it. Chemset bolts are used to fix the column to the pad footing. Above the pad is packing sand, a void barrier (polathene), formwork followed by reinforcement. Once these are put in place the slab is poured.
The slab is poured in sections. At the front of the column a line (construction joint) can be seen which is created due to the slab being poured in sections. The first section of the slab is poured. Before the second section is poured a type of material to create a joint is installed (e.g. fibreboard, corking etc.). The second section of the slab is then poured.
This column is located in the centre of the warehouse. Formwork has been installed in a circulation shape around the column. The slab around this column has been poured in four sections as indicated by the lines veering off in four differnt directions. Generally, columns are located on grid lines which are shown on working drawings.
During fabrication, cleats with holes which have been punched or drilled out are welded to the columns. These are used as a means of fixing girts to columns. Attached to these girts are the steel sheets used as cladding which are fixed to the girts using screws with rubber washers.
Cross bracing for the walls is used. One end of the rod is fixed to the beam and the other to the base of the column as above. A thread exists on the rod which goes though the adjustment plate. A bolts is used to tension and loosen the rods. The building can be plumbed and leveled with the use of this bracing system.
The slab in this photo has been prepared and ready to pour. The void barrier (polathene) has been laid out and formwork has been put in place and fixed with wooden pegs. The concrete will be poured to the level of the formwork in the slab (not the level of the formwork around the columns). Generally 4 to 5 days will be required before the concrete is at a structurally acceptable MPa rating.
Fly bracing is located at regular intervals. This reduces over turning of the purlins. These are bolted to the purlins and bolted to a bracket which is welded to the beam/rafter.
This photo also shows fire services which have been installed prior to the installation of the slab. Having the structure installed before the slab eliminates the possibility of inclement weather affecting the pouring of the slab. The slab could have been poured before the structure was complete but problems in relation to weather such as too much or too little heat, rain, humidy can affect the ability to pour the slab.
The structure has been completed and part of the slab poured. Formwork has been positioned for construction joints in the slab and isolation joints around the columns. Concreters have begun to roll out the void barrier. When complete the slab wil be ready to pour.
A mechnical screeding machine is used to level and compact the concrete. During the concrete pouring process the concrete is placed by concreters, the mechanical vibrator eliminates air entrapped in the concrete and then a screeding machine is used. The machine has a hydraulic arm which advances and retracts so it can level and compact.
With the use of concrete truck the concrete is transported from the concrete plant to site and poured as required. Concreters work the concrete with shovels.
The mechanical vibrator in this photo is used to vibrate the concrete from the inside. It is placed into the concrete quickly and removed slowly. It helps remove air from inside the pour which gives the concrete a higher compressive strength.
After the mechanical screed process is finished bull floating is done to flatten the surface and elimante surface cracks.
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