Light bracing cleat connections are defined as unstiffened cleats that connect light bracing such as flat bars, rods or small tubes sections (round or square) to beams or columns (figure 1). These types of bracing systems are typically used in low rise industrial and retail buildings as roof and wall bracing (Hogan and Collins, 2010).

Bridge construction is a demanding application typically requiring plate welded sections. Material optimisation for welded plate sections involves a careful matching of strength requirements with available plate sizes to minimise waste and welding requirements and to reduce transportation costs. This optimisation process is an iterative one. Typically a preliminary design is undertaken to determine the required plate thicknesses, dimensions and splice locations. Once material availability has been confirmed with a steel distributor, the designer continues to refine the design to suit actual plate availability and supply lead-times. To minimise the number of iterations in this process, it is helpful to have a feel for the range of plate sizes produced by steel mills. Typically local steel distributors will stock only a limited range of commonly used standard sheet sizes, however most are willing to explore stock options for special projects. 10mm loss of plate width should be allowed for in the cutting process.

Some changes to the way NZ welders qualify for structural welding will result from the Standards NZ announcement in March 2010 that NZS 4711 is to be withdrawn. With effect from 1 April 2011, new or renewal welder qualifications will not be available under this Standard. For most users of NZS 4711, AS/NZS 2980:2007 Qualification of Welders for Fusion Welding of Steels, will become the standard for welder qualification.

Galvanic corrosion is the additional corrosion that occurs when dissimilar metals are in contact in the presence of an electrolyte. The corrosion of a metal, the anode, results from the positive current flowing from the anode to the less reactive (more noble) metal, the cathode, through the electrolyte. Contact between dissimilar metals occurs frequently but is often not a problem. This article identifies what causes galvanic corrosion and how to avoid it. This article summarises material from the Australian Stainless Steel Development Association and the use of this material is gratefully acknowledged.

This article provides an example of how to design the boom of a jib crane to NZS 3404 (SNZ, 2007). This example illustrates the use of second order and restraint requirements of NZS 3404.

The design of moment resisting seismic frames can by optimised with the use of reduced beam sections. In a reduced beam section (RBS) moment connection (figure 1), portions of the beam flanges are selectively trimmed in the region adjacent to the beam to column connection. Yielding and hinge formation are intended to occur primarily within the reduced section of the beam and there by limit the design actions and the inelastic deformation demands developed at the face of the column. The development, research, design rules, design consideration and benefits of the RBS are covered in previous Steel Advisor articles EQK1002 and EQK1003. This article illustrates the application of the RBS design rules by way of a design example.

The design of moment resisting seismic frames can by optimised with the use of reduced beam sections. In a reduced beam section (RBS) moment connection (Figure 1) portions of the beam flanges are selectively trimmed in the region adjacent to the beam to column connection. Yielding and hinge formation are intended to occur primarily within the reduced section of the beam and there by limit the design actions and the inelastic deformation demands developed at the face of the column. The development, research and design rules of this type of connection are discussed in a previous Steel Advisor article EQK1002. This article highlights some of the design considerations and benefits of using reduced beam sections with moment resisting seismic frames.

Structural design for large seismic events must explicitly consider the effects of response beyond the elastic range. The moment resisting seismic frame is designed to form beam plastic hinges near the face of the column. After the discovery of brittle fractures in steel moment frame welded connections in the 1994 Northridge earthquake in California, the reduced beam section (RBS) moment connection was developed and is now extensively used throughout North America and other parts of the world. The intent of the RBS is to move the plastic hinge region away from the face of the column (figure 2). This is accomplished by reducing the beam's actual plastic moment by removing part of the beam flange as shown in figure 1. This reduced section creates a weaker location where yielding and plastic hinge formation is expected to occur, and results in a reduced moment that develops at the face of the column. By reducing moment demands at the column face the beam-column connections and the column panel zone requirements are reduced. Further more, the use of RBS may also lead to smaller column sizes.

In October 2009, Steel Construction New Zealand Inc. (SCNZ), ran technical seminars throughout NZ. One of the topics covered was 'Portal Frame Design Tips', presented by the Manager of SCNZ, Clark Hyland. These proceedings outline the main message delivered on this topic at the seminar series and were edited by Kevin Cowie. This paper summarises material predominantly from two Australian Steel Institute (Woolcook et al, 1999; Hogan et al, 1997), and one Steel Construction Institute (Salter, 2004) publications, contextualised for New Zealand practice in accordance with the New Zealand Steel Structures Standard NZS 3404 (SNZ, 2007). The use of these referenced documents in particular are gratefully acknowledged.

The material in this paper draws on previous SCNZ and HERA reports (Fussell et al 2006, Barber and Clifton 1994 and Clifton 2006) which cover the ultimate limit state design of metal slabs subject to concentrated loading and fire engineering design. The intention is to cover issues not addressed by any of these previous documents, namely fire design and deflection limits for metal deck slabs subject to concentrated loading. The emphasis is on directing structural engineers to appropriate sources of design guidance and where required, how to modify this design guidance to address fire design and serviceability issues. To make this document easy to read alongside these earlier publications, the original notation where possible is used.

All steel members which form part of a seismic resisting frame are classified into one of 4 categories for the purpose of seismic design. Category 1 members are capable of sustaining high displacement ductility demands. Category 2 members are capable of sustaining low ductility demands. Category 3 members are capable of developing their nominal section capacity where required to in bending. Category 4 members need not be designed to sustain any displacement ductility demand. Limits are placed on member section geometry for the various categories and this is found in section 12.5 of the Steel Structures Standard (SNZ, 2007). Previous tables have been developed classifying I section members into the appropriate categories (Feeney, 1993). These tables were developed based on the 1992 version of the Steel Structures Standard . Hot rolled steel sections classified were grades 250 and 350. Welded sections classified were limited to WB and WC sections. This article updates the Member ductility category of I sections for seismic design tables for Grade 300 welded sections in accordance with the latest Steel Structures Standard (SNZ, 2007).

All steel members which form part of a seismic resisting frame are classified into one of 4 categories for the purpose of seismic design. Category 1 members are capable of sustaining high displacement ductility demands. Category 2 members are capable of sustaining low ductility demands. Category 3 members are capable of developing their nominal section capacity where required to in bending. Category 4 members need not be designed to sustain any displacement ductility demand. Limits are placed on member section geometry for the various categories and this is found in section 12.5 of the Steel Structures Standard (SNZ, 2007). Previous tables have been developed classifying I section members into the appropriate categories (Feeney, 1993). These tables were developed based on the 1992 version of the Steel Structures Standard . Hot rolled steel sections classified were grades 250 and 350. Welded sections classified were limited to WB and WC sections. This article updates the Member ductility category of I sections for seismic design tables for Grade 300 hot rolled sections in accordance with the latest Steel Structures Standard (SNZ, 2007).

This article provides general guidance on applying the lateral restraint provisions for yielding regions given in Clause 12.6.2 of NZS3404 (SNZ, 2007) to columns and beams of multi-storey buildings. It includes simplification of those provisions which can be made when designing these types of member.

A M7.6 earthquake, with depth 80 km, occurred near Padang City, Sumatra, Indonesia on September 30, 2009. The overwhelming majority of the buildings damaged were reinforced concrete frames with unreinforced brick infill panels, reflecting the popularity of this form of construction in the affected area. However some important lessons can be learned from observations of the performance of the few steel structures affected. Two of these collapsed dramatically, tragically killing over 200 people.

No distinction is made in the Steel Structures Standard NZS 3404 (SNZ, 2007) between the design ply bearing capacity for a long slotted hole in which the slot is perpendicular to the direction of the bearing load and a standard circular hole. See figure 1. While the presence of a slotted hole does not reduce ply bearing capacity based on strength, there is increased hole elongation for a given bolt shear force compared to a standard hole. In this article, a design equation based on North American practice is presented for design ply bearing capacity limited by hole elongation. This equation will be applicable for situations such as seismic loading, where increased hole elongation associated with slotted holes loaded transverse to the direction of the bearing load is undesirable.