scholarly journals The seismic behaviour of plywood sheathed shearwalls

Author(s):  
J. A. Dean ◽  
W. G. Stewart ◽  
A. J. Carr

Plywood sheathed timber shearwalls are commonly incorporated in timber structures to resist wind and earthquake induced lateral, forces. Such shearwalls are classified in the NZS 4203:1984 earthquake loading provisions as being ductile and are currently designed to earthquake load levels of 25% of the smoothed elastic response spectrum force, i.e. corresponding to SM = 1 in terms of NZS 4203:1984 notation. However, a case study is examined which illustrates that compliance with the NZS 3603:1981 permissible wind-seismic connection load and stress levels does not ensure ductility. Recommendations are made for a capacity design procedure in which the sheathing nailing acts as the ductile load limiting element. Even when this is achieved, cyclic loading of the walls at seismic design load levels causes progressive degrading of strength and stiffness properties resulting in a pinched hysteretic loop. The displacement demands on walls in which this occurs when subjected to a design intensity earthquake ground motion are compared in the paper with the corresponding displacement demands on elastic plastic structures. Selected test results are presented of eleven full scale shearwalls subjected to cyclic static and shaketable loading. The performance of the sheathing nailing, framing connections and foundation connections is reported in detail. Based on the test observations and an analysis of the force distribution within the framing, particular details are recommended to ensure ductile response. A theoretical time history single degree of freedom dynamic idealisation is described which represents the observed wall behaviour, and which is suitable for incorporation into multistorey analyses.

2020 ◽  
Vol 20 (01) ◽  
pp. 35-46
Author(s):  
Nugraha Bintang Wirawan ◽  
Siska Apriwelni

[EN] Lampung, a province where Institut Teknologi Sumatera (ITERA) is located, is an area that has a high level of seismicity. This research takes a case study of the Building E ITERA which has a dilatation building concept. Due to dilatation, inter-buildings have the risk of collisions because of earthquake loads. The purpose of this study is to determine the value of joint displacement in adjacent buildings when given a dynamic load of Time History and determine whether the adjacent buildings experience a pounding effect. A Time History earthquake load data that has been matched with the Lampung region response spectrum by software is applied to the model of Building E. Building E is modeled according to the as built drawing data and the results of field checking. Structure is analyzed using software. The results of the study showed that the structure of the Building E which was loaded by Loma Prieta earthquake that has been matched would experience inter-building collisions. Further research using earthquake record data taken in areas within certain radius from ITERA is need to be conducted to obtain more accurate results.


2009 ◽  
Vol 25 (3) ◽  
pp. 583-605 ◽  
Author(s):  
Wei Chiang Pang ◽  
David V. Rosowsky

This paper presents a direct displacement design (DDD) procedure that can be used for seismic design of multistory wood-framed structures. The proposed procedure is applicable to any pure shear deforming system. The design procedure is a promising design tool for performance-based seismic design since it allows consideration of multiple performance objectives (e.g., damage limitation, safety requirements) without requiring the engineer to perform a complex finite element or nonlinear time-history analysis of the complete structure. A simple procedure based on normalized modal analysis is used to convert the code-specified acceleration response spectrum into a set of interstory drift spectra. These spectra can be used to determine the minimum stiffness required for each floor based on the drift limit requirements. Specific shear walls can then be directly selected from a database of backbone curves. The procedure is illustrated on the design of two three-story ATC-63 archetype buildings, and the results are validated using nonlinear time-history analysis.


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.


2020 ◽  
Vol 10 (11) ◽  
pp. 3942 ◽  
Author(s):  
Heungbae Gil ◽  
Kyoungbong Han ◽  
Junho Gong ◽  
Dooyong Cho

In areas of civil engineering, the resilient friction base isolator (R-FBI) system has been used due to its enhanced isolation performance under seismic excitations. However, because nonlinear behavior of the R-FBI should be reflected in seismic design, effective stiffness (Keff) of the R-FBI is uniformly applied at both peak ground acceleration (PGA) of 0.08 g and 0.154 g which use a multimodal response spectrum (RS) method analysis. For rational seismic design of bridges, it should be required to evaluate the dynamics of the R-FBI from in-field tests and to improve the seismic design procedure based on the performance level of the bridges. The objective of this study is to evaluate the dynamics of the R-FBI and to suggest the performance-based seismic design method for cable-supported bridges with the R-FBI. From the comparison between the experiments’ results and modal shape analyses, the modal shape analyses using primary (Ku) or infinite stiffness (fixed end) showed a great agreement with the experimental results compared to the application of Keff in the shape analysis. Additionally, the RS or nonlinear time history method analyses by the PGA levels should be applied by reflecting the dynamic characteristics of the R-FBI for the reasonable and efficient seismic design.


Author(s):  
Kanthi Srirengan ◽  
Partha Chakrabarti ◽  
Rupak Ghosh

Two novel methods namely the Dominant Modes method and the All Modes method to predict the seismic-pushover load for the jacket-type structures are presented. Both of these methods are based on the linear superposition of the modal reactions. As a preliminary evaluation, the linear elastic response of a jacket structure subjected to seismic-pushover loads is compared with that obtained from the response spectrum analysis. Furthermore, the nonlinear inelastic behavior obtained from the seismic-pushover analysis is compared with that obtained from the nonlinear time-history analysis, for a portal frame subjected to El Centro earthquake motion. When more than one mode is dominant in an excitation direction, both the linear elastic and the nonlinear inelastic responses obtained using the loads generated from the All Modes method are representative of the reference solutions.


2015 ◽  
Vol 31 (2) ◽  
pp. 617-635 ◽  
Author(s):  
Gang Wang ◽  
Robert Youngs ◽  
Maurice Power ◽  
Zhihua Li

The Design Ground Motion Library (DGML) is an interactive tool for selecting earthquake ground motion time histories based on contemporary knowledge and engineering practice. It was created from a ground motion database that consists of 3,182 records from shallow crustal earthquakes in active tectonic regions rotated to fault-normal and fault-parallel directions. The DGML enables users to construct design response spectra based on Next-Generation Attenuation (NGA) relationships, including conditional mean spectra, code spectra, and user-specified spectra. It has the broad capability of searching for time history record sets in the database on the basis of the similarity of a record's response spectral shape to a design response spectrum over a user-defined period range. Selection criteria considering other ground motion characteristics and user needs are also provided. The DGML has been adapted for online application by the Pacific Earthquake Engineering Research Center (PEER) and incorporated as a beta version on the PEER database website.


2013 ◽  
Vol 40 (8) ◽  
pp. 815-825 ◽  
Author(s):  
Payam Tehrani ◽  
Denis Mitchell

The longitudinal seismic responses of 4-span continuous bridges designed based on the 2006 Canadian Highway Bridge Design Code were studied using elastic response spectrum and inelastic time-history analyses. Several boundary conditions including unrestrained horizontal movements at the abutments and different abutment stiffnesses were considered in the nonlinear analyses. The seismic response of more than 2600 bridges were studied to determine the effects of different design and modelling parameters including the effects of different column heights, column diameters, and superstructure mass as well as different abutment stiffnesses. The bridges were designed using two different force modification factors of 3 and 5. The effects of column stiffness ratios on the elastic and inelastic analysis results, maximum ductility demands, concentration of ductility demands, and demand to capacity ratios were investigated. The results indicate that the seismic response and maximum ductility demands in the longitudinal direction are influenced by important parameters such as the total stiffness of the substructure, the column stiffness ratio, and the aspect ratio of the columns.


2014 ◽  
Vol 6 (2) ◽  
pp. 43-61 ◽  
Author(s):  
Shehata E. Abdel Raheem ◽  
Mohamed M. Ahmed ◽  
Tarek M. A. Alazrak

Recent studies show that the effects of Soil Structure Interaction (SSI) may be detrimental to the seismic response of structure and neglecting SSI in analysis may lead to un-conservative design. Despite this, the conventional design procedure usually involves assumption of fixity at the base of foundation neglecting the flexibility of the foundation, the compressibility of soil mass and consequently the effect of foundation settlement on further redistribution of bending moment and shear force demands. The effects of SSI are analyzed for typical multi-story building resting on raft foundation. Three methods of analysis are used for seismic demands evaluation of the target moment resistant frame buildings: equivalent static load (ESL); response spectrum (RS) methods and nonlinear time history (TH) analysis with suit of nine time history records. Three-dimensional Finite Element (FE) model is constructed to analyze the effects of different soil conditions and number of stories on the vibration characteristics and seismic response demands of building structures. Numerical results obtained using soil structure interaction model conditions are compared to those corresponding to fixed-base support conditions. The peak responses of story shear, story moment, story displacement, story drift, moments at beam ends, as well as force of inner columns are analyzed.


2010 ◽  
Vol 163-167 ◽  
pp. 3981-3986
Author(s):  
Mohammad Saeed Masoomi ◽  
Siti Aminah Osman ◽  
Shahed Shojaeipour

This paper presents the nonlinear time-history and response spectrum analysis for a three-story steel moment frame and a braced frame by hysteretic damper against earthquake load which analyzed by SAP2000 software. The mentioned frames were analyzed by Eigenvalue method for linear analysis and Ritz-vector method for nonlinear analysis. Simulation results were presented as a time-displacement graph based on dynamic analysis, the dynamic base shear force is also calculated.


2006 ◽  
Vol 33 (10) ◽  
pp. 1251-1260 ◽  
Author(s):  
Hyunhoon Choi ◽  
Jinkoo Kim ◽  
Lan Chung

The conventional energy-based seismic design procedure based on the energy-balance concept was revised for performance-based design of buckling-restrained braced frames. The errors associated with the energy-balance concept were identified and were corrected by implementing proper correction factors. The design process began with the computation of the input energy from a response spectrum. Then the plastic energy computed based on the modified energy-balance concept was distributed to each story and the cross-sectional area of each brace was computed in such a way that all the plastic energy was dissipated by the brace. The proposed procedure was applied to the design of three-, six-, and eight-story steel frames with buckling-restrained braces for three different performance targets. According to the time-history analysis results, the mean values of the top story displacements of the model structures, designed in accordance with the proposed procedure, corresponded well with the given target displacements. Key words: energy-balance concept, buckling-restrained braces, hysteretic energy, performance-based seismic design.


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