Economic Aspects of Partial Strength Connection in The Design of Braced Steel Frame using Trapezoid Web Profiled Steel Sections

摘要

Eurocode 3 offers the opportunity to design steel frames as ‘semi-continuous’ by including the moment resistance of ‘partial strength’ connections in plastic hinge analysis of the frame. Compared to conventional pinned-jointed simple construction, semi-continuous construction with partial strength joints offers the benefits for braced frames such as shallower and lighter beams, standardized connections with less complicated geometry, and more robust frame than simple construction. It is expected to result in significant savings in frame weight. This paper presents findings on a series of two-bay and four-bay braced frames of two, four, six and eight storey with span ranging from 6m to 9m by comparing between simple construction design with semi-continuous construction design using trapezoidal web profiled steel section as a beam. The aim of this parametric study was to obtain the economical sizes for the beams, based on the minimum weight or lightest section of beams in particular, and columns. The aspect of economical in term of the total weight of frames was accounted only for the weight of the beams and columns. The weights of other components, for example the fittings, were assumed to be marginally small to affect the total weight of frames and were identical for all of the frames designed using either construction method. Trapezoidal Web Profiled (TWP) sections were adopted in both construction methods. However, the TWP section is only used for the design of the beam; the column section was designed using the universal column of British sections. Flush end-plate connections were used as partial strength joints whereas for simple construction, partial depth flexible end-plate connections were used as pin joints. The connections used were based on the standardised tables established by the authors using component method proposed by Steel Construction Institute. The design of beam and column was based on BS 5950:2000 Part 1. The results of the percentage weight savings are analysed and discussed base on the effect of increasing the beam span from 6m to 9m, the effect of using Flush end-plate, and the effect of increasing the number of bays. From the study, it was concluded that the percentage of savings using partial strength connection was in the range of 6.97% to 16.34% depending on the design variables.