Structural, technological and Aesthetical Considerations for the Detailing of Steel Tubular Joints

<p>For the majority of steel outdoor facilities (towers, masts, billboards and traffic-sign supporting structures) wind loading is the governing factor for determining their resistance and stiffness. In many cases fatigue-related issues appear, with cracking and failure in the welded connections of tubular joints or in the parent metal adjacent to the welds.</p><p>Structural detailing of the joints in steel tubular structures subjected to repeated cyclic loading is of great importance for their fatigue strength. Sharp changes in the shape, sharp turns in the welds and notches give rise to high stress concentration. The combined effect of discontinuities and stress concentration is the main cause for the formation and propagation of fatigue cracks. When detailing the erection joints it is also necessary to observe technological requirements related to efficiency of fabrication. For the civil engineering works exposed to public it is indispensable to include additional requirements for the aesthetic appearance of their visible structural parts. The design experience shows that applying aesthetic considerations to steel tubular joint detailing may contribute to satisfying the increased fatigue strength requirements.</p><p>The paper presents a study on the wind action on a specific kind of civil engineering works (traffic- sign supporting structures) and the approach used for its determination. The leading structural, technological and aesthetic criteria to be implemented in the detailing of tubular erection joints are formulated. An example of tubular joint destroyed due to propagation of fatigue crack is given and possible options for the joint repair are proposed. Numerical modeling and analyses of the original and repaired joints have been carried out in order to make conclusions for the advantages and shortcomings of the joint repair options.</p>

B2P Rutaka Footbridge – Improving Safety using Innovative Deck Pull Method

<p>In developing nations, rural communities often lack year-round safe access to local markets, farms, schools, health clinics and other critical services. Bridges to Prosperity has developed standard footbridge designs and construction methodologies to successfully construct over 200 footbridges.</p><p>This paper presents a case study of the 40m long suspended footbridge constructed in the community of Rutaka in Rwanda in 2017. The normal deck construction method required the operatives to spend a significant amount of time working at height. The industry team set themselves a challenge to reduce this.</p><p>The team successfully developed and trialled a methodology for launching the deck from a platform on the river bank, improving safety and quality control. It is a significant step forward in the development of safety and construction methods for Bridges to Prosperity.</p>

Design of the viaducts for the Line 3 of the Riyadh Metro LRT in Saudi Arabia

<p>In June 2013, three consortia were awarded the three construction packages that constitute the whole Riyadh Metro Project in Saudi Arabia for a total of 6 lines and 180 kilometres.</p><p>International Bridge Technologies was in charge, as a subconsultant of Idom, of the complete structural scope of services for the 25.6 km of elevated viaduct that Riyadh Metro Package 2 comprises (Line 3, around 41.6 km, out of which 25.6 km are elevated). This scope consisted of the full range of services from conceptual tender design to final detailed design, including shop drawings production, construction engineering and construction site support.</p><p>The Line 3 elevated viaduct consists of a three-cells precast segmental box-girder with typical simply-supported spans of 37 m and special continuous spans of 50 m. Six long span structures with spans varying from 60 m to 95 m were required for the special crossings over existing interchanges. Typical and continuous spans are erected span-by-span with an overhead truss while long spans are erected in balanced cantilever with cranes on the ground or lifting frames on the deck.</p><p>The present paper is centred on the design of the elevated viaduct and presents the different structures with key features and how they were constructed to permit large scale standardisation and speed of construction. Some key design aspects are developed, in particular the design approach for the 3-cells box-girder as the most effective solution to satisfy the imposed aesthetic criteria. This paper also exposes the design approach adopted to produce a “design-for-demand” by relying as much as practically possible on a realistic modelling of the alignment and by limiting parametric design. This allowed for an optimisation of material quantities.</p>

A Review on Prestressed Transfer Plate Analysis and Design

<p>Prestressed transfer plate consists of a thick cast in-situ post-tensioned concrete slab supporting multi-storey shear walls at building transition level. Compared to conventional reinforced concrete transfer beams, it offers savings in concrete volume of 10-15%, cuts steel reinforcement content by 35-50% and significantly reduces formwork usage which eventually helps to achieve lower carbon footprint for a more sustainable transfer floor construction. The design of prestressed transfer plates is complicated owing to its two-way bending behaviour and irregular load path from reactions of numerous shear walls. This paper elaborates the analysis of prestressed transfer plates and discusses their interaction effect with shear walls. It also explains the design of interfacing shear for thick plate construction with multi-layer casting in addition to various design considerations including flexural and punching shear design based on relevant codes of practice.</p>

Mechanical Behaviour of Steel-Concrete Twin I-Girder Bridges

<p>Steel-concrete composite twin I-girder bridges have been built a lot in both Europe and Japan, but the lack of redundancy has always been a concern in U.S. and many other countries. In addition, few experimental studies have been performed on the mechanical performance of such bridges, particularly for the intact bridges. On this background, a steel-concrete composite twin I-Girder bridge model was designed according to the current highway bridge design specification in Japan and tested in the laboratory. The static loading tests were performed, and two loading conditions including both symmetrical loading and unsymmetrical loading were applied. Load versus deflection relationships were measured in the loading test, and the failure mode of the test specimen was discussed. The flexural strain development on bottom flanges of two main girders was also reported in this paper to confirm the load transfer between two main girders. In addition, the theoretical results on the basis of the classic theory were also provided to compare with the test results. The comparison indicates that the theoretical analyses can predict the behaviour of the twin I-girder bridges very well in the elastic stage by considering the effective width of the slab. The load transfer paths in such bridges were also discussed on the basis of the test results under un-symmetrical loading.</p>

Planning, Design and Construction of Elevated Guideway of Kelana Jaya (KLJ LRT) Extension Project and Challenges & Lessons Learnt

<p>Building a transportation infrastructure for fast growing city like Petaling Jaya (considered twin city with Kuala Lumpur), Malaysia is always challenging and difficult works. One of the major infrastructure projects, the 17 km long elevated guideway which form the extension of Kelana Jaya Light Rail Transit (KLJ LRT) i.e Putra line is opened for service since 30th June 2016. The elevated viaduct was designed to build extensively using precast technique. The time efficient proven technique of span by span precast segmental construction along with some crossings with precast balanced cantilever construction was implemented for the project. Cast-in-situ box girder and precast U-beams with in-situ deck were also used for bifurcation and pocket track areas. Majority of the stations (9 out of 12) for KLJ LRT Extension are island platform stations and this has major impacts on interface in constructions, time and cost. The requirement of island platform station was one of the main criteria for the operator i.e RapidKL which is part of Prasarana.</p><p>Curved and skewed alignment over major 6 lanes highways and commuter lines necessitates a span as large as 100 m with 3 span balanced cantilever structure. Prestressed pier column were introduced due to space constraint. Precast split segments were also introduced to overcome difficulties in handling and delivery of deeper segments.</p><p>This paper describes the design scheme and contractual set up of guideway structures and presents an overview of construction and also related issues, incidents etc.</p>

The Harbour Passage Bridge in Hamburg

<p>The Harbour Passage Bridge in Hamburg is an outstanding motorway bridge project in Germany today. The bridge, with a total length of 5.7 km, is the key structure in the extension of the federal motorway A 26. Three parts of the bridge can be defined. First, the crossing of the Süderelbe, a cable-stayed structure is projected with a main span of 350 m. The second main feature is a bridge circle that functions as an intersection. The third feature is the eastern part of the bridge. A modular system is projected setting values on simple construction and erection methods.</p>

Klang Valley MRT Viaduct Structural Design Development

<p>The Klang Valley Mass Rapid Transit (KVMRT) rail system is a central part of the development of the Kuala Lumpur public transportation network with MRTC the project owner and MMC Gamuda KVMRT (PDP SSP) the Project Delivery Partner. The first MRT line stretches from Sungai Buloh to Kajang (SBK) with a length of 51km, while the second line from Sungai Buloh to Serdang to Putrajaya (SSP) has a length of 52km. The majority of both lines is supported on viaducts which weave their way through the urban environment. This paper presents the development of the viaduct design for the SBK Line and the lessons learnt that were incorporated into the SSP Line viaduct design. The process of optimising the design to meet the requirements for both the SBK and SSP Lines will be discussed while some key technical aspects of the viaduct design will be highlighted.</p>