The economical advantages of the use of S460 steel

Abstract

This master’s thesis is about the use of higher strength steel in buildings and the economical advantages of the use of this steel. The economical advantages are examined based on a comparison of similar designs with the use of the steel grades S355 and S460. The latter could in some cases result in large weight and cost savings. The costs are examined for trusses and columns. The trusses are applied to transfer loads from 5 different floors to columns up to 40 m apart. The columns are examined for a high-rise office with 24 stories. For all the components examined the costs have been calculated. These costs are divided into 4 different groups: Material, fabrication, transportation and assembly costs. When designing constructions with the use of S460 large material cost savings can be expected. Due to the excellent properties of this steel grade the use of S460 is beneficial for both light weight and heavy sections. For heavy sections exceptionally large material cost savings can be expected. The use of this steel grade should however be limited to axially loaded members only. Fabrication costs are more difficult to describe than the material costs. Stronger steel grades have a larger hardness which makes sawing and drilling for example more difficult. The reduced thicknesses that can be achieved by using S460 can however be assumed to compensate for this increased difficulty. Fabrication costs will ultimately not differ much from the costs required for a design with the use of S355. Assembly costs can be reduced due to the lower weight of the components. If trusses are used the total weight can be reduced significantly and the use of smaller cranes is therefore possible. The time required for construction will not change much but the costs for the required equipment could decrease significantly due to the decreased weight. The transportation costs can also be reduced because of the reduced weight. Less trucks are required to transport sections and plates to the construction site which results in a cost reduction proportional to the weight saving. The total costs for a steel structure will be lower when S460 is used. The costs for beams cannot be reduced because the use of S460 is very inefficient in these cases. A steel structure can therefore be designed with the use of S460 for the columns and S355 for beams to achieve an optimal economical design.