Heavy Metal

The site was quiet for a week and a half but things were going on. Once the slab was down it was time to erect the steel so we met on site with the steel contractor and measured the as built conditions. The slab has been built very accurately but steelwork needs to be millimeter perfect because it sets up the rest of the work. We also had to take into account the uneveness of the existing building and any level changes in the slab. The builder, X, measured and re-measured as the steel contractor noted sizes. We then all left the site.

Some days later we received the ‘shop drawings’ drawn by the fabricators draughtsman. We reviewed these and made minor comments and then sent the drawings back as approved. The fabricators then manufactured the steel in their factory and sent parts of it to get galvanised.

On the friday the steel contractors came to site and fixed threaded studs into the slab. They did this by drilling into the slab, inserting a chemset 2 part adhesive compound into the holes and then pushing the studs into the concrete. These studs would, amazingly, hold up the steelwork. 

The steel arrived on a truck on Monday, the columns weighed about 250kg and the beams were around 500kg. This steel was unloaded onto a trolley that enabled it to be moved. Also arriving was a small crane to lift it all. Again we felt fortunate that the Department of Housing allowed us access to the site. Without this it would have been much harder to put up the steel work. One portal frame was done at a time. First the steel columns went up and were carefully checked to make sure they were plumb. This was done by having a small metal shim under the base plates of each column and then tightening the nuts at the base plate to adjust the angle of the columns. Then the lower beam was bolted in place finally the upper beam was fixed. It was re-checked for squareness and then all the bolts were tightened. After this the second portal frame was erected. It was all finished by mid afternoon.