Improvements in the direct displacement-based design procedure for mid-rise steel MRFs equipped with viscous dampers

Structures ◽  
2021 ◽  
Vol 34 ◽  
pp. 1636-1650
Author(s):  
Seyed Behdad Alehojjat ◽  
Omid Bahar ◽  
Masood Yakhchalian
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.


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):  
Anagha Girish Malu ◽  
Satyabrata Choudhury

The Direct Displacement-Based Design (DDBD) method has become a popular seismic design tool for structures. It takes drift as the performance criterion while designing structures. This method overcomes the shortcomings of the traditional force-based seismic design method, which considers peak force as the design parameter. In terms of structural damage, deflection is a better indicator, and hence, DDBD is a more acceptable method for seismic design. In this paper, a 12-story RC frame building with supplemental damping has been designed and investigated using a direct procedure of calculation, while considering the displacement-based design method. The performance of building with and without viscous dampers for a particular performance level has been compared. The effects of the non-linearity of dampers have also been discussed, and the effect of constant and story proportional drift proportional damper forces have been investigated. The results of various cases have been compared. It has been found that drift proportional story shear proportional carried damper design leads to construction economy.


2015 ◽  
Vol 31 (1) ◽  
pp. 179-196 ◽  
Author(s):  
Afsoon Nicknam ◽  
Andre Filiatrault

A direct displacement-based design (DDBD) methodology is described for propped rocking walls (PRWs). PRWs represent a novel seismic force-resisting system that combines passive supplemental damping devices with unbonded post-tensioned concrete rocking walls. The key aspect of the proposed design procedure is the closed-form derivation of the stabilized hysteretic response of PRWs under reverse cyclic loading. This allows the direct application of the DDBD procedure to satisfy desired displacement performance objectives under prescribed levels of seismic intensity. Nonlinear response analyses are conducted on a prototype PRW structure, designed according to the proposed DDBD procedure to evaluate its performance under strong ground shaking.


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.


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.


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