Walid Tizani

BIM extension for the sustainability appraisal of conceptual steel design

Contemporary advancements in Information Technology and the efforts from various research initiatives in the AEC industry are showing evidence of progress with the emergence of building information mod- elling (BIM). BIM presents the opportunity of electronically modelling and managing the vast amount of information embedded in a building project, from its conception to end-of-life. Researchers have been looking at extensions to expand its scope. Sustainability is one such modelling extension that is in need of development. This is becoming pertinent for the structural engineer as recent design criteria have put great emphasis on the sustainability credentials in addition to the traditional criteria of structural integrity, constructability and cost. With the complexity of designs, there are now needs to provide deci- sion support tools to aid in the assessment of the sustainability credentials of design solutions. Such tools would be most beneficial at the conceptual design stage so that sustainability is built into the design solu- tion starting from its inception. The sustainability of buildings is related to life cycle and is measured using indicator-terms such as life cycle costing, ecological footprint and carbon footprint. This paper proposes a modelling framework combining these three indicators in providing sustainability assessments of alterna- tive design solutions based on the economic and environmental sustainability pillars. It employs the prin- ciples of feature-based modelling to extract construction-specific information from product models for the purposes of sustainability analysis. A prototype system is implemented using .NET and linked to the BIM enabled software, Revit StructuresTM. The system appraises alternative design solutions using multi-crite- ria performance analysis. This work demonstrates that current process and data modelling techniques can be employed to model sustainability related information to inform decisions right from the early stages of structural design. It concludes that the utilized information modelling representations – in the form of a process model, implementation algorithms and object-based instantiations – can capture sustainability related information to inform decisions at the early stages of the structural design process.

Advances and challenges in computing in civil and building engineering

This paper provides an overview of the advances presented in the manuscripts included in this issue. The authors of these manuscripts were asked to propose future directions and challenges in their respective research areas. This paper summarises these proposals and concludes with general directions and challenges related to computing in civil and building engineering. The suggested directions include enhancing digital information modelling and extending the standardised product and process modelling technologies; improving decision-support capabilities and decision-implication analysis through integrating wider-aspects of the problem space; embedding optimisation techniques more holistically; and integrating all of these by making more use of virtualisation in an attempt to simplify the use of the output technologies. The challenges that will arise as a consequence will inevitably include reducing the inherent complexity in such a manner that the resulting models are both realistic and useable by all of the disciplines involved. Another main challenge is the inclusion of concepts that are significant but less readily formalised than traditional engineering ones. It could be argued that the high-level directions and challenges mentioned above are not very different from those that could have been predicted a considerable number of years ago. However, it is worth stressing that, with increased capabilities and reach of information technologies and greater expectations of decision makers, the current ambitions are an order of magnitude greater. The proposed directions and the resulting challenges are now much greater in both scale and breadth.

Performance of T-Stub to CFT Joints Using Blind Bolts with Headed Anchors

This paper assesses the performance of a newly developed blind bolt, intended for use in constructing bolted moment-resisting connections to concrete-filled tubular steel profiles. A total of ten connection tests are reported, with each configuration having been subjected to a predominantly tensile force in a representation of the tension region of a typical moment connection. The test variables included type of fastener, addition of concrete to the tube, strength of the concrete, spacing among bolts, and bolt class. On the basis of reformability response, the benefits of filling the tubular member with concrete are highlighted. The favorable performance that results from using a relatively, high-grade concrete infill is also highlighted. The addition of a concrete infill to the tube stiffens and strengthens the otherwise relatively flexible tube walls, enhancing overall connection behavior in terms of stiffness, strength, and ductility. The performance of connections to concrete-filled tubular steel profiles using blind bolts with headed anchors is shown to be suitable for moment-resisting construction.

Object-oriented fabrication cost model for the economic appraisal of tubular truss design

This paper is concerned with the development of a knowledge-based system for the economical design of tubular trusses using a fabrication-led approach. For this purpose the system employs a cost model for estimating the likely cost of fabrication for these trusses. The cost model, which was developed using the object-oriented methodology, is used for estimating the cost of fabrication of one or a number of trusses, joint detailing, members and individual fabrication operations. Therefore, the relative cost of one design option compared with its alternatives can be obtained. Using the model, the consequences of design decisions on the cost of fabrication can be appraised. This will assist in obtaining economical designs that take into account not only the cost of material but also that of fabrication.

Welding automation in space-frame bridge construction

The SPACES system has been proposed as an alternative for long-span bridge construction. Tubular space frames offer a structurally more efficient solution for bridges, but they have been considered too expensive because the joints at the nodal intersections of the tubular members are difficult and expensive to weld. The benefits of the SPACES system can only be realized by using a computer-integrated construction system to drive down the fabrication costs. A key component of the computer-integrated construction is the robotic welding system. This article describes the development of a lightweight automated welding system for the joining of tubular members. It addresses the geometry of intersecting cylinders and the kinematics and design of a 5-degree-of-freedom manipulator: Summary solutions are given for both. The control software is described briefly, and mention of the welding tests and overall business process is also made. A consortium of U.K. industry and universities is conducting the work.

Building Information Modelling (BIM) - Versioning for collaborative design

The engineering design process is a complicated activity. It is often characterized by multi-disciplinary teams in multiple places working together on a single project, using different models and software tools. In addition, such activities generate a large amount of data that require exchange among designers and stages of the work. In industry, the current collaboration approaches often focus on integrating and managing multiple models from multi-designers. Building Information Modelling (BIM) is playing a major role in facilitating collaboration. BIM provides an opportunity to electronically model and manage the vast amount of information embedded in a building project, from conception to completion. In the building design process, changes and modifications are inevitable even in the contemporary BIM approach. Such changes need to be well managed to keep track of changes to ensure that designers have an up-to-date version of the BIM model. The main goal of this research is to develop a collaborative BIM platform that tackles the challenges of integrating object versioning, as a change management approach, and an IFC model, as data representation of BIM. This has been done through suggesting new IFC extensions to add further concepts representing the history of changing to any object of the model. It also explores possibilities of adding or merging object-based change information to existing BIM models to enable the representation of design intentions, identification of affected changes numerically and visually. A prototype system is implemented in C#, using .NET framework and Revit API platform. This paper concludes that the proposed system can contribute to improving collaboration - in terms of tracking and management of affected changes during multi-disciplinary design process.

Incremental Virtual Prototyping as an IT Tool for CE Projects

Virtual prototyping is an effective design technique that consists of designing and developing a ‘virtual model’ which represents a real life scenario and allows for the gauging of the designs compliance and performance through a series of ‘virtual tests’. Virtual prototyping has been used in industries where the function and performance requirements are concise, the solution space is small, and the design process is close-knit typically involving interactions between a few wellestablished design teams. The building industry has considerably different traits and so faces a unique challenge in attempting to adopt virtual prototyping as a design technique. This paper advocates that such a technology should be applied in the design of civil engineering projects and more specifically building design. It assesses the feasibility of using what is termed ‘Incremental Virtual Prototyping’ in the design of buildings and outlines some of the challenges that its implementation might face.

Integrated Design System for Semi-Rigidly Connected Steel Frames

A prototype Integrated Design System (IDS) for semi-rigid steel frames is reported. The aim of this system is: (i) to assist designers in conducting the overall analysis required for the frames, (ii) to provide designers with a tool to design the frames economically in terms of the total cost of the frame. The system works by guiding the users towards appropriate design decisions that recognise the cost of the frames — not just material costs but also fabrication costs. Recognition of the semi-rigid and partial strength characteristics of beam-to-column connections means that the internal force distribution in a frame depends on the analysis method adopted. A successful design for a frame requires a balanced internal force distribution between the connections and the members. To assist in achieving this, a number of analysis methods have been incorporated into the system. A detailed economic appraisal of semi-rigid frame designs is presented by means of a worked example. This illustrates global comparisons between the use of alternative analysis methods as well as between alternative options in the detailing of the connections. The benefits that can be obtained from using the system at both the conceptual and the detailed design stages are demonstrated.

A construction-led design process for tubular trusses

Abstract This paper describes a process for the design of tubular steel trusses using a construction-led approach. This process does not aim at automating the design of this type of structure, rather it aims at facilitating knowledge-aided design whereby the designer is fully in charge of design decisions aided by knowledge about the effect of these decisions on construction of a structure.

Bolts Gauge Effect on the Face Bending Behaviour of Concrete-Filled Hollow Section for Hollo-Bolted Connections

This paper investigates the effect of bolt gauge on the face bending behaviour of concrete-filled Square Hollow Sections (SHS) in Hollo-Bolted connections. A set of full-scale experiments were undertaken to examine the effects of varying the bolt gauge on the SHS face bending behaviour while controlling all other parameters. Typical experiment involved one row of two bolts pulled out of concrete-filled SHS. A special dummy bolts were manufactured to the exact size and geometry of open Hollo-Bolts, and were used in the experiments to remove the influence of any deformation associated with the real Hollo-Bolts, and isolate the face bending behaviour. Non-contact video-based equipment was used to record the SHS face deformation. This deformation is recorded as force-displacement relationship which is commonly used to represent the structural behaviour of similar components, and typically defined by initial stiffness, yield force and post yield stiffness. Across the range considered in this investigation, it was found that varying the bolt gauge to SHS width ratio have a significant effect on the concrete-filled SHS face in bending component. Both the initial stiffness and the yield force of the component were found to increase with the increase of the bolt gauge. The Post-Yield stiffness was not affected by the change in bolt gauge.