1. the type of I-steel is fixed, its "code" is not very complete, for example: 32#c I-steel size is 320X134X13.5, and then the largest is 36#a (360X136X10), the choice is small; Second, his section height and width dimensions are only a few, if you want to meet the design conditions, often produce waste, for example, sometimes the web conditions may be met, the flange is not enough.
2. I steel is a hot rolling molding, its advantage is low unit price, easy processing, if the steel column and beam, two ends of the welding end plate. The H-shaped steel requires the web and the wing plate to be welded, which relatively increases a large number of welding and processing welding deformation procedures. I-steel is the finished product size (that is, the length is mostly 12 meters), and H-shaped steel is mostly completed after multiple steps such as cutting, welding and straightening according to the size given by the design drawings in the processing plant, so the unit price of I-steel is low.
There is also a small waste of section size, and when using I-beams with design margin, the cost is lower than that of H-beams, saving costs. However, such engineering examples are rare, and this is not a common design idea.
3. steel structure design is now basically dependent on computer software, if you want to use I-steel design also depends on whether the software is supported, the specific use also needs the designer's experience and comparison, if you want to put into practice will increase the workload of designers.
