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Construction management in practice
Published in Fred Sherratt, Peter Farrell, Introduction to Construction Management, 2023
Taking this even further, projects can be designed for demolition, where elements of the construction, such as the steel frame, are designed specifically to be taken apart easily and removed when the project is no longer needed, ready to be reused elsewhere.
Influence of SMA brace arrangement on seismic performance of frame structure
Published in Domenico Lombardo, Ke Wang, Advances in Materials Science and Engineering, 2021
Steel frame structure is a structure form widely used at present. Traditional steel frame structure may produce large lateral deformation under earthquake action, which is easy to cause large residual displacement or damage [1]. SMA is a kind of good energy dissipating material, and SMA braces can effectively improve the seismic performance of steel frame structures, which has outstanding advantages over the buckling restrained braces and traditional structures [2]. Common since the restoration of frame structure way of supporting configuration with v-shaped, inverted V and diagonal bracing, etc., for the same steel frame structure, different ways of brace arrangement on seismic performance of structures, affect the brace force and the stress of the beam. As a result, this paper studies different SAM brace arrangement of structure seismic performance influence.
Materials for motorcycles
Published in Andrew Livesey, Motorcycle Engineering, 2021
If a steel frame is not overloaded, it will retain its strength for its lifetime. An example outside the motorcycling world is the use of steel joists in buildings – these will remain straight and true if the building is not overloaded.
Replaceable Rotational Viscoelastic Dampers for Improving Structural Damping and Resilience of Steel Frames
Published in Journal of Earthquake Engineering, 2023
Zhan Shu, Zhaozhuo Gan, Cheng Fang, Gregory MacRae, Hanlin Dong, Yazhou Xie
Structural steel frame is a major structural type which demonstrates many advantages such as good ductility, reduced time of construction, and good compatibility with other systems (e.g., core-wall) and constructional materials (e.g., concrete and timber) (Li et al. 2018; Lignos, Moreno, and Billington 2014). The energy dissipation capacity of a steel frame is usually provided by the ductile yielding behavior of the steel members. This also means that very limited system damping is provided unless plastic deformation occurs. Reinoso and Miranda (2005) analyzed six tall buildings located in California and found that the lower bound damping ratio of the steel buildings is only 0.5% due to small deformations. Furthermore, the inherent damping of a steel structure decreases further when the structural height increases (Cruz and Miranda 2017). The structural damping of steel frames is therefore rather inconsistent compared with the 4 to 6% damping ratio that is usually considered in reinforced concrete structures before yielding occurs.
Effect of Damper Sub-System Stiffness on the Response of a Single Degree of Freedom System Equipped with a Viscous Damper
Published in Journal of Earthquake Engineering, 2022
R. Xie, G. W. Rodgers, T. J. Sullivan
Some insight into the significance of damper sub-system stiffness for nonlinear viscous dampers has been provided by Dong, Sause, and Ricles (2016) as part of a large-scale experimental investigation of a multi-story steel frame building. The test structure underwent both design basis and maximum considered ground motions using real-time hybrid simulation. Results from this experimental study concluded that a steel frame would perform significantly better during all levels of seismic events than a bare conventional steel moment resisting frame. Additionally, this literature also provided the interesting observation that the deformations of structural components and connections adjacent to the dampers caused the local deformations of the nonlinear viscous dampers to be different to the story drift. This phenomenon, referred to as the “brace flexibility” effect by the authors, caused the damper responses to be partially out-of-phase with the structural responses, and as a result, the brace flexibility effect added stiffness to the steel frame equipped with viscous dampers (Fig. 1). The term “brace” in the work of Dong et al. indicates the damper sub-system that provides connection between the damper and the main structure. Furthermore, Dong (2016) used an equivalent linear elastic-viscous model to simulate a damper-sub-system component in order to further investigate the effect of sub-system stiffness on the response of a frame structure. This study stated that a more flexible sub-system stiffens a structure and the sub-system stiffness also affects the effective damping of the structure.
Discussion of ‘Practical wisdom in an age of computerisation’ by David Blockley
Published in Civil Engineering and Environmental Systems, 2021
The proposed solution would have dealt with the problem, but it was not a sensible approach. First, the building had already been through two earthquakes at or above the design level with no more than minor damage. It had been proof loaded, so to speak. Second, the engineer chose to forget the way in which the building was designed to act, which was to let all four resisting elements act independently. The proposal to brace the roof would mean that all lateral load would be taken off the portal frame because it was far more flexible than the block walls. Practical wisdom would say that a more sensible, simpler and far cheaper solution would have been to work with the original thinking behind the structural system rather than against it and add a steel beam to the exterior of the building spanning from B to D, rather than roof bracing. This would have taken a proportion of the load from C and wall B would have been adequate. Such a solution would have considered the nature of how the building was designed to act, not work against it. In any case, the action of the structure in an actual earthquake would be dynamic, not static, so that any excursion of the steel frame into yield would produce only a small distortion, not failure. The engineer had followed the code requirements and focussed on the numbers without thinking about how the building would actually behave. For me, this showed a lack of practical wisdom. The paper’s author might care to comment on whether this interpretation of ‘practical wisdom’ is correct.