Seismic force modification factors for light-gauge steel-frame - wood structural panel shear walls

2007 ◽  
Vol 34 (1) ◽  
pp. 56-65 ◽  
Author(s):  
F A Boudreault ◽  
C Blais ◽  
C A Rogers

Design guidelines for laterally loaded light-gauge steel-frame – wood structural panel shear walls are not available in Canadian codes. A design method for the calculation of shear stiffness and strength has been developed for use with the 2005 National Building Code of Canada (NBCC), however. This method was based on the analysis, using an equivalent energy elastic–plastic (EEEP) approach, of over 180 single-storey shear wall tests of various configurations. Ductility-related (Rd) and overstrength-related (Ro) force modification factors also need to be defined to calculate equivalent static seismic forces following the 2005 NBCC. This paper describes the development of these two factors based on the EEEP analysis of the shear wall test results. To verify the "test-based" Rdand Rovalues, nonlinear time-history dynamic analyses of two representative buildings were carried out using a suite of 10 earthquake records scaled to the 2% in 50 year uniform hazard spectrum (UHS) for Vancouver, British Columbia. Preliminary values have been determined for the force modification factors, namely Rd= 2.5 and Ro= 1.7.Key words: shear wall, light-gauge steel, wood structural panel, seismic, R value.

2006 ◽  
Vol 33 (7) ◽  
pp. 872-889 ◽  
Author(s):  
A E Branston ◽  
F A Boudreault ◽  
C Y Chen ◽  
C A Rogers

Design guidelines for laterally loaded (wind and seismic) light-gauge steel-frame – wood structural panel shear walls are currently unavailable in Canadian standards and codes. A research project was initiated at McGill University in 2001 with the objective of developing a shear wall design method that could be used in conjunction with the 2005 National Building Code of Canada (NBCC). An extensive program of tests was first carried out to establish a database of shear wall information. The equivalent energy elastic–plastic (EEEP) analysis approach was then chosen to derive key design parameters for the shear walls, including nominal shear strength, elastic stiffness, overstrength, and ductility. This paper presents the development of the proposed design method, the resulting nominal strength and unit elastic stiffness values according to typical perimeter fastener schedules and sheathing type, and the calibration of a resistance factor to the 2005 NBCC wind loads. Overstrength values used for a capacity-based seismic design approach and factors of safety for wind loading are also provided.Key words: shear wall, light-gauge steel, wood structural panel, earthquake, wind, design.


2006 ◽  
Vol 33 (5) ◽  
pp. 561-572 ◽  
Author(s):  
A E Branston ◽  
C Y Chen ◽  
F A Boudreault ◽  
C A Rogers

At present, no Canadian document is available with which engineers can design light-gauge steel-frame – wood structural panel shear walls that are relied upon to resist lateral in-plane loading (earthquake and wind). For this reason, a research project was initiated with the overall goal of developing a shear wall design method that could be used in conjunction with the 2005 National Building Code of Canada. The initial phase of the project was to conduct an experimental study to provide information on the response of single-storey shear walls. An extensive program of tests was completed on walls composed of 1.12 mm thick 230 MPa grade steel framing sheathed with 12.5 mm Douglas-fir plywood, Canadian softwood plywood, or 11 mm oriented strand board wood structural panels. Various wall lengths and connection patterns were incorporated into the program of monotonic and reversed cyclic tests. The scope of testing was selected such that it added to the North American database of information for steel-frame – wood structural panel shear walls. Information on the test program and the general results are provided in this paper.Key words: shear wall, light-gauge steel, wood structural panel, earthquake, wind.


2006 ◽  
Vol 33 (5) ◽  
pp. 573-587 ◽  
Author(s):  
C Y Chen ◽  
F A Boudreault ◽  
A E Branston ◽  
C A Rogers

The second phase of the research project to develop a shear wall design method that could be used in conjunction with the 2005 National Building Code of Canada involved evaluation of the performance characteristics of the tested steel-frame – wood structural panel shear walls. A nonlinear and pinched resistance versus deflection hysteretic behaviour was exhibited, although in most cases the walls could sustain large inelastic deformation cycles with limited strength degradation. A significant amount of energy could be dissipated under reversed cyclic loading. Walls 1220 mm and 2440 mm in length were able to develop their maximum capacity at similar displacement levels; however, the 610 mm long walls required significantly larger displacements prior to reaching their ultimate shear resistance. The performance of the walls was directly linked to the behaviour of the sheathing-to-framing screw connections, except in one case in which local buckling of the chord studs controlled the ultimate shear resistance. Given the behaviour observed during testing, this type of wall construction can be relied on to resist lateral loading, including earthquake effects in the inelastic range, assuming the designer ensures that failure of the wall is limited to the sheathing-to-framing connections.Key words: shear wall, light-gauge steel, wood structural panel, earthquake, wind.


2021 ◽  
Author(s):  
Tulio Carrero Enrique ◽  
Jairo Montaño ◽  
Sebastián Berwart ◽  
Hernán Santa María ◽  
Pablo Guindos

Abstract This paper examines the seismic behavior of CLT-steel hybrid walls at six- and ten-story heights to increase seismic force resistance compared to a conventional wooden wall. The ultra-strong shear walls proposed in this paper are called Framing Panel Shear Walls (FPSW), which are based on a robust articulated steel frame braced with CLT board panels and steel tendons. Timber structures are well-known for their ecological benefits, as well as their excellent seismic performance, mainly due to high strength-to-weight ratio compared to steel and concrete ones, flexibility, and redundancy. However, in order to meet the requirements regarding the maximum inter-story drifts prescribed in seismic design codes, a challenging engineering problem emerges, because sufficiently resistant, rigid and ductile connections and lateral assemblies are not available for timber to meet both the technical and economical restrictions. Therefore, it is a necessity to develop strong and cost-effective timber-based lateral systems, in order to become a real alternative to mid- and high-rises, especially in seismic countries. In this investigation, the dynamic response of cross-laminated timber (CLT) combined with hollow steel profiles has been investigated in shear wall configuration. After experimental work, an investigation was also carried out into numerical modelling for simulating the cyclic behavior of a hybrid FPSW wall and the spectral modal analysis of a six- and a ten-story buildings with FPSW. A FPSW shear wall can double the capacity and stiffness.


2014 ◽  
Vol 2014 ◽  
pp. 1-18
Author(s):  
G. Muthukumar ◽  
Manoj Kumar

Shear walls have been conferred as a major lateral load resisting element in a building in any seismic prone zone. It is essential to determine behavior of shear wall in the preelastic and postelastic stage. Shear walls may be provided with openings due to functional requirement of the building. The size and location of opening may play a significant role in the response of shear walls. Though it is a well known fact that size of openings affects the structural response of shear walls significantly, there is no clear consensus on the behavior of shear walls under different opening locations. The present study aims to study the dynamic behavior of shear walls under various opening locations using nonlinear finite element analysis using degenerated shell element with assumed strain approach. Only material nonlinearity has been considered using plasticity approach. A five-parameter Willam-Warnke failure criterion is considered to define the yielding/crushing of the concrete with tensile cutoff. The time history responses have been plotted for all opening cases with and without ductile detailing. The analysis has been done for different damping ratios. It has been observed that the large number of small openings resulted in better displacement response.


2013 ◽  
Vol 07 (05) ◽  
pp. 1350038 ◽  
Author(s):  
WAIEL MOWRTAGE (VAIL KARAKALE)

To strengthen reinforced concrete (RC) structures against possible future earthquakes, several techniques are used in practice such as adding new RC shear walls, column jacketing using steel or RC or carbon fibers, adding steel bracing, and using seismic isolation and dampers. To apply these techniques, the whole building or part of it should be evacuated for several months and if this building is a school or a factory it means that the building will lose its function for several months during the strengthening construction. In this paper, parallel braced steel frame strengthening technique is proposed to strengthen the low or middle raise RC structures in which all the construction works are applied from outside of the building and do not affect the building function. The main features of this technique are ensuring the view, ventilation, and sunlight from windows after the retrofitting work is done. Furthermore, using the construction steel members lead to shortening the construction term, improve in quality, and reduce costs. The idea of this technique is to reduce the earthquake displacement demand on the nonductile existing RC structures by attaching steel frames to the building floors. These frames are parallel to the structural system of the building and their foundations are connected to the existing building's foundation. In doing so, it is expected that during an earthquake the building's interstory drifts will reduce in half and prevent building collapse. The parallel steel frames can be designed to the desired limit states using performance-based design method in FEMA or Turkish earthquake code. A study case of a factory building in Turkey is presented. The seismic performance of the building before and after the strengthening was evaluated according to the Turkish earthquake code TERDC-2007. Analysis results indicate the effectiveness of the proposed technique.


2014 ◽  
Vol 41 (4) ◽  
pp. 323-332 ◽  
Author(s):  
Michael R. Dupuis ◽  
Tyler D.D. Best ◽  
Kenneth J. Elwood ◽  
Donald L. Anderson

Architectural features and other irregularities in the gravity system which apply gravity-induced lateral demands to the seismic force resisting system are being incorporated in new buildings. These gravity-induced demands have raised concerns due to the perceived potential for a ratcheting effect to occur during seismic loading. This paper summarizes the results of a study to identify if there are behavioral trends not recognized within the scope of current building codes. To this end, a nonlinear, parametric study was conducted in OpenSees to investigate the inelastic response of concrete shear wall buildings with a range of design characteristics, including gravity-induced lateral demands. The results demonstrated that a seismic ratcheting effect can develop and amplify inelastic displacement demands. The effect is significantly more prevalent in coupled shear walls compared with cantilevered shear walls. An irregularity class to address buildings with gravity-induced lateral demands on the seismic force resisting system is proposed for the 2015 National Building Code of Canada.


2012 ◽  
Vol 39 (7) ◽  
pp. 723-737 ◽  
Author(s):  
Yannick Boivin ◽  
Patrick Paultre

A parametric study of regular ductile reinforced concrete (RC) cantilever walls designed with the 2010 National building code of Canada and the 2004 Canadian Standards Association (CSA) standard A23.3 for Vancouver is performed to investigate the influence of the following parameters on the higher mode amplification effects, and hence on the seismic force demand: number of storeys, fundamental lateral period (T), site class, wall aspect ratio, wall cross-section, and wall base flexural overstrength (γw). The study is based on inelastic time-history analyses performed with a multilayer beam model and a smeared membrane model accounting for inelastic shear–flexure–axial interaction. The main conclusions are that (i) T and γware the studied parameters affecting the most dynamic shear amplification and seismic force demand, (ii) the 2004 CSA standard A23.3 capacity design methods are inadequate, and (iii) a single plastic hinge design may be inadequate and unsafe for regular ductile RC walls with γw < 2.0.


2006 ◽  
Vol 33 (7) ◽  
pp. 854-871 ◽  
Author(s):  
M Panneton ◽  
P Léger ◽  
R Tremblay

An eight-storey reinforced concrete shear wall building located in Montréal and designed according to the 1995 National Building Code of Canada (NBCC) and the Canadian Standards Association standard CSA-A23.3-94 is studied to evaluate the impact of new requirements for inclusion in new editions of the NBCC and CSA-A23.3. Static and modal analyses were conducted according to the 2005 NBCC (draft 2003) and CSA-A23.3-04 (draft 4) procedures, and three-dimensional dynamic inelastic time history analysis was performed using three earthquake records. The building is braced by four flat shear walls and three cores. Various estimates of the fundamental period of vibration based on empirical expressions presented in the literature or structural models with different stiffness assumptions were examined. The analysis also permitted the study of the displacement and force demand on the lateral load resisting system. It was found that the base shear from the 2005 NBCC is 29% higher than the 1995 NBCC value when code empirical formulae are used for the fundamental period of vibration.Key words: building, shear wall, inelastic seismic response, NBCC, CSA-A23.3 design of concrete structures.


Sign in / Sign up

Export Citation Format

Share Document