Direct Displacement-Based Design of a RC wall-steel EBF dual system with added dampers

Author(s):  
Timothy J. Sullivan

An innovative application of Direct Displacement-Based Design (DBD) is presented for a modern 8-storey dual system structure consisting of interior concrete walls in parallel to a number of large steel eccentrically braced frames, fitted with visco-elastic dampers at link positions. The innovative DBD methodology lets the designer directly control the forces in the structure by choosing strength proportions at the start of the design procedure. The strength proportions are used to establish the displaced shape at peak response and thereby establish the equivalent single-degree-of-freedom system design displacement, mass and effective height. A new simplified formulation for the equivalent viscous damping of systems possessing viscous dampers is proposed which also utilises the strength proportions chosen by the designer at the start of the process. The DBD approach developed is relatively quick to use, enabling the seismic design of the 8-storey case study structure to be undertaken without the development of a computer model. To verify the ability of the design method, non-linear time-history analyses are undertaken using a suite of spectrum-compatible accelerograms. These analyses demonstrate that the design solution successfully achieves the design objectives to limit building deformations, and therefore damage.

Author(s):  
Timothy J. Sullivan

An innovative application of Direct Displacement-Based Design (DBD) is presented for a modern 8-storey dual system structure consisting of interior concrete walls in parallel to a number of large steel eccentrically braced frames, fitted with visco-elastic dampers at link positions. The innovative DBD methodology lets the designer directly control the forces in the structure by choosing strength proportions at the start of the design procedure. The strength proportions are used to establish the displaced shape at peak response and thereby establish the equivalent single-degree-of-freedom system design displacement, mass and effective height. A new simplified formulation for the equivalent viscous damping of systems possessing viscous dampers is proposed which also utilises the strength proportions chosen by the designer at the start of the process. The DBD approach developed is relatively quick to use, enabling the seismic design of the 8-storey case study structure to be undertaken without the development of a computer model. To verify the ability of the design method, non-linear time-history analyses are undertaken using a suite of spectrum-compatible accelerograms. These analyses demonstrate that the design solution successfully achieves the design objectives to limit building deformations, and therefore damage.


Author(s):  
Matthew J. Fox ◽  
Timothy J. Sullivan ◽  
Katrin Beyer

Reinforced concrete coupled walls are a common lateral load resisting system used in multi-storey buildings. The effect of the coupling beams can improve seismic performance, but at the same time adds complexity to the design procedure. A case study coupled wall building is designed using Force-Based Design (FBD) and Direct Displacement-Based Design (DDBD) and in the case of the latter a step by step design example is provided. Distributed plasticity fibre-section beam element numerical models of the coupled walls are developed in which coupling beams are represented by diagonal truss elements and experimental results are used to confirm that this approach can provide a good representation of hysteretic behaviour. The accuracy of the two different design methods is then assessed by comparing the design predictions to the results of non-linear time-history analyses. It is shown that the DDBD approach gives an accurate prediction of inter-storey drift response. The FBD approach, in accordance with NZS1170.5 and NZS3101, is shown to include an impractical procedure for the assignment of coupling beam strengths and code equations for the calculation of coupling beam characteristics appear to include errors. Finally, the work highlights differences between the P-delta considerations that are made in FBD and DDBD, and shows that the code results are very sensitive to the way in which P-delta effects are accounted for.


Author(s):  
Andrea Belleri ◽  
Simone Labò

AbstractThe seismic performance of precast portal frames typical of the industrial and commercial sector could be generally improved by providing additional mechanical devices at the beam-to-column joint. Such devices could provide an additional degree of fixity and energy dissipation in a joint generally characterized by a dry hinged connection, adopted to speed-up the construction phase. Another advantage of placing additional devices at the beam-to-column joint is the possibility to act as a fuse, concentrating the seismic damage on few sacrificial and replaceable elements. A procedure to design precast portal frames adopting additional devices is provided herein. The procedure moves from the Displacement-Based Design methodology proposed by M.J.N. Priestley, and it is applicable for both the design of new structures and the retrofit of existing ones. After the derivation of the required analytical formulations, the procedure is applied to select the additional devices for a new and an existing structural system. The validation through non-linear time history analyses allows to highlight the advantages and drawbacks of the considered devices and to prove the effectiveness of the proposed design procedure.


2020 ◽  
Vol 8 (5) ◽  
pp. 5153-5160

Numerous studies are reported in literature on performance evaluation and rehabilitation of building however, limited studies are reported on performance based design of new buildings. Displacement based design procedure is a new method which is not available in Indian building design codes. An effort has been done to investigate the Direct Displacement Based Design (DDBD) for four, eight and twelve story regular RC frame buildings proposed by Priestley et al, using Indian code Response Spectrum for Zone V which is considered as a very high intensity seismic risk zone for life safety and collapse prevention performance levels. Nonlinear time history analysis is carried out for available ground motion and compared with the performance levels (in terms of drift, displacement). Observations show that design displacement reduction factor should be different for life safety and collapse prevention levels. The effective damping increases as the height of the building increases and is higher for collapse prevention.


2019 ◽  
Vol 19 (3) ◽  
pp. 162
Author(s):  
Annisaa Dina Puspita ◽  
Anis Rosyidah

The Force Based Design (FBD) and the Direct Displacement-Based Design (DDBD) are methods for designing seismic-resistant buildings. Building structures designed, are expected to be suitable with the purpose and usefulness of a building. For this reason, this study compares the performance of dual system structures using the DDBD and FBD methods that aim to prove better performance with consideration of safety against users during an earthquake. This research method uses design analysis method to compare the value of the base shear force, reinforcement ratio, and performance level using software for static nonlinear pushover analysis. The results showed the value of the base shear force x direction of the DDBD method was 17.57% smaller than the FBD method, whereas for the y direction the DDBD value was greater than 9.38% of the FBD. The value of the reinforcement ratio of the beam, column and shear wall results is greater DDBD than FBD. The actual drift of the DDBD and FBD methods is slightly different. So that both are at the same level of performance, namely damage control. The performance level has not reached the performance target of life safety design in DDBD, but the structure has met the level performance requirements for offices.


Author(s):  
J.L. Ceballos C. ◽  
T.J. Sullivan

The use of hybrid joints to provide pre-cast concrete and timber structures with ductile response and self-centering capability is becoming increasingly popular in New Zealand, as is evident by the increasing number of building solutions that incorporate the technology as well as the design provisions for hybrid systems currently included in the New Zealand Concrete standard. This paper raises some issues with the current code approach to estimate the inelastic seismic displacement demand on hybrid systems. The work then presents the results of a series of non-linear time history analyses of single degree of freedom (SDOF) systems characterised by the flag-shaped hysteretic rule, in order to identify a general, improved expression for the equivalent viscous damping of hybrid systems. The new equivalent viscous damping expression is expected to provide more reliable control of inelastic displacement demands for hybrid systems design used Displacement-Based Design (DBD) procedures. In addition, the last part of the paper also discusses how the findings in the paper could be utilised to provide improved control of displacement demands when hybrid systems are designed using force-based procedures.


2003 ◽  
Vol 19 (3) ◽  
pp. 357-364
Author(s):  
Y.-Y. Lin ◽  
K.-C. Chang

AbstractTraditionally, the yield displacement of a nonlinear structure was calculated by using the direct displacement-based seismic design method which usually requires a repeatedly iterative procedure no matter whether the substitute structure or inelastic design spectra has been adopted in the procedure. This will sometimes result in inefficiency if too many iterative cycles need to be produced in a design case for convergency. To avoid this disadvantage, this paper presents a non-iterative direct displacement-based design procedure for SDOF steel columns using the substitute structure approach. By combining the yielding property with the stiffness property of the designed steel columns, the procedure can immediately obtain the column's cross-section via the chosen target displacement and ductility ratio.


2021 ◽  
Vol 11 (8) ◽  
pp. 3425
Author(s):  
Marco Zucca ◽  
Nicola Longarini ◽  
Marco Simoncelli ◽  
Aly Mousaad Aly

The paper presents a proposed framework to optimize the tuned mass damper (TMD) design, useful for seismic improvement of slender masonry structures. A historical masonry chimney located in northern Italy was considered to illustrate the proposed TMD design procedure and to evaluate the seismic performance of the system. The optimization process was subdivided into two fundamental phases. In the first phase, the main TMD parameters were defined starting from the dynamic behavior of the chimney by finite element modeling (FEM). A series of linear time-history analyses were carried out to point out the structural improvements in terms of top displacement, base shear, and bending moment. In the second phase, masonry's nonlinear behavior was considered, and a fiber model of the chimney was implemented. Pushover analyses were performed to obtain the capacity curve of the structure and to evaluate the performance of the TMD. The results of the linear and nonlinear analysis reveal the effectiveness of the proposed TMD design procedure for slender masonry structures.


2012 ◽  
Vol 594-597 ◽  
pp. 795-799
Author(s):  
Gui Tao Chen ◽  
De Min Wei

A displacement-based optimization design method of RC structure was proposed by combining direct displacement-based design method with nonlinear programming technique. To avert the influence of target displacement, the stationary constraint displacement was presented, and the target displacement can be updated during the optimal design process. Principle of virtual work and Gaussian integral method was employed to simplify the explicit relationship between horizontal displacement and the section dimension. Comparison analysis of the local optimal results corresponding to different displacement shapes was conducted to achieve global optimal design. The numerical tests presented demonstrate the computational advantages of the discussed methods and suggesting that the proposed method is a reliably and efficiently tool for displacement-based optimal design.


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