Safety of gravity-load columns in shear wall buildings designed to Canadian standard CSA A23.3

2010 ◽  
Vol 37 (11) ◽  
pp. 1451-1461 ◽  
Author(s):  
Perry Adebar ◽  
Poureya Bazargani ◽  
James Mutrie ◽  
Denis Mitchell
Keyword(s):  
Nonlinear Analysis ◽  
Plastic Hinge ◽  
Shear Walls ◽  
Canadian Standard Association ◽  
Design Rule ◽  
Seismic Demands ◽  
Gravity Load ◽  
Load Carrying ◽  
Bar Buckling ◽  
Design Earthquake

It has been a Canadian code requirement for 25 years to check whether concrete gravity-load columns can tolerate the building deformations due to the design earthquake; but the way this has typically been done using linear analysis significantly underestimates the seismic demands on gravity-load columns. Concern about the safety of gravity-load columns over the plastic hinge height of concrete shear walls, particularly elongated wall-like gravity-load columns, has resulted in new design requirements in Update No. 3 of Canadian Standard Association (CSA) A23.3–04 issued in August 2009. The current paper provides the background to these new requirements. If nonlinear analysis is not done, closely spaced seismic hoops shall be provided in all columns and walls that support gravity loads, and these members shall meet the same limit on maximum compression strain depth as concrete shear walls. The results of nonlinear analyses were used to validate this simple design rule, and to investigate factors that increase seismic demands on gravity-load columns such as diagonal cracking of concrete shear walls, localized damage of columns from cover spalling and bar buckling, and larger first storey heights. Nonlinear analysis has shown that 2.4 m (8 ft) long columns can lose over 50% of their axial load carrying capacity at an inelastic drift ratio of only 1%.

Damage to concrete structures due to the 1994 Northridge earthquake

1995 ◽  
Vol 22 (2) ◽  
pp. 361-377 ◽  
Author(s):  
Denis Mitchell ◽  
Ronald H. DeVall ◽  
Murat Saatcioglu ◽  
Robert Simpson ◽  
René Tinawi ◽  
...  
Keyword(s):  
Seismic Design ◽  
Precast Concrete ◽  
Concrete Structures ◽  
Shear Walls ◽  
Northridge Earthquake ◽  
Short Columns ◽  
Gravity Load ◽  
Current Design ◽  
Design Earthquake ◽  
1994 Northridge Earthquake

Observations on damage to concrete structures, due to the 1994 Northridge earthquake, are reported from a Canadian code perspective. Most of the damaged structures were older, nonductile, structures that do not conform to current design and detailing requirements. Concern is expressed about the seismic hazard of older Canadian structures having similar deficiencies. A significant number of parking structures suffered extensive damage and a number of precast concrete parking structures collapsed. Deficiencies in these structures include lack of proper diaphragm connections, a mix of gravity load columns with ductile framing, inappropriate number and distribution of shear walls, torsional effects caused by ramps, and the creation of short columns due to geometric features. This earthquake also demonstrated the deficiencies in connections of pre-1973 tilt-up structures. Key words: seismic design, earthquake, Northridge, structures, codes, concrete, precast concrete.

Comparison of Seismic Behaviors of Interior Joints in PT and RC Flat Plate Systems

2007 ◽  
Vol 348-349 ◽  
pp. 741-745
Author(s):  
Young Mi Park ◽  
Sang Whan Han ◽  
Jong Hyuk Ryu
Keyword(s):  
Flat Plate ◽  
Seismic Performance ◽  
Shear Walls ◽  
Actual Behavior ◽  
Lateral Loads ◽  
Moment Frames ◽  
Gravity Load ◽  
Load Carrying ◽  
Rc Slab ◽  
Seismic Behaviors

The purpose of this study is to compare the seismic behaviors of interior post-tensioned (PT) and reinforced concrete (RC) flat plate slab-column connections designed to resist only gravity loads. In general, flat plate systems have been used to support gravity loads, which should be constructed with lateral system such as shear walls or moment frames. Flat plate systems should retain the ability to undergo the lateral drift associated with the lateral system without loss of gravity load carrying capacity. Although these systems are common, relatively little experimental study has been conducted to assess actual behavior under lateral loads. Therefore, this study was undertaken to assess the seismic performance of two PT and one RC slab-column interior connection under high gravity loads. This study observed that PT connections had a better seismic performance than corresponding RC connections in terms strength, deformability, energy absorption.

scholarly journals Experimental Investigation of Steel Plate Shear Walls under Shear-Compression Interaction

2019 ◽  
Vol 2019 ◽  
pp. 1-11
Author(s):  
Yang Lv ◽  
Ling Li ◽  
Di Wu ◽  
Bo Zhong ◽  
Yu Chen ◽  
...  
Keyword(s):  
Stress Distribution ◽  
Steel Plate ◽  
Axial Stress ◽  
Shear Walls ◽  
Shear Capacity ◽  
Steel Plate Shear Walls ◽  
Steel Plate Shear Wall ◽  
Gravity Load ◽  
Moment Resisting ◽  
Axial Stress Distribution

Four scaled one-storey single-bay steel plate shear wall (SPSW) specimens with unstiffened panels were tested to determine their behaviour under cyclic loadings. The shear walls had moment-resisting beam-to-column connections. Four different vertical loads, i.e., 300 kN, 600 kN, 900 kN, and 1200 kN, representing the gravity load of the upper storeys were applied at the top of the boundary columns through a force distribution beam. A horizontal cyclic load was then applied at the top of the specimens. The specimen behaviour, envelope curves, axial stress distribution of the infill steel plate, and shear capacity were analyzed. The axial stress distribution and envelope curves were compared with the values predicted using an analytical model available in the literature.

Shear strength of stiffened steel shear walls with considering the gravity load effect through a three-segment distribution

Structures ◽  
2021 ◽  
Vol 29 ◽  
pp. 265-272
Author(s):  
Jie Li ◽  
Jia-Qi Lv ◽  
Vinu Sivakumar ◽  
Yu Chen ◽  
Xin Huang ◽  
...  
Keyword(s):  
Shear Strength ◽  
Shear Walls ◽  
Load Effect ◽  
Gravity Load ◽  
Segment Distribution ◽  
Stiffened Steel

scholarly journals A simple method for determining seismic demands on gravity load frames

2017 ◽  
Vol 44 (8) ◽  
pp. 661-673 ◽  
Author(s):  
J. Beauchamp ◽  
P. Paultre ◽  
P. Léger
Keyword(s):  
Response Spectrum ◽  
Time History ◽  
Bending Moment ◽  
New Method ◽  
Simple Method ◽  
Seismic Demands ◽  
Gravity Load ◽  
Comparison Results ◽  
Seismic Force ◽  
Nonlinear Time History

This paper presents a simple method based on modal response spectrum analysis to compute internal forces in structural elements belonging to gravity framing not part of the seismic force resisting system (SFRS). It is required that demands on these gravity load resisting system (GLRS) be determined according to the design displacement profile of the SFRS. The proposed new method uses the fact that if the linear stiffness properties of the GLRS not part of the SFRS have negligible values compared to those of the SFRS, only the latter will provide lateral resistance. Displacements of the GLRS then correspond to those of the SFRS alone. The new method is illustrated by computing the seismic responses of a symmetric and an asymmetric multi-storey reinforced concrete building. These results are compared to those obtained from the application of the simplified analysis method proposed in the Canadian standard for the design of concrete structures. Nonlinear time history analyses are also performed to provide a benchmark for comparison. Results show that the new method can predict shear and bending moment in all members at once with ease. Therefore, this new simplified method can effectively be used to predict seismic forces in elements not considered part of the SFRS.

Experimental Investigation on Seismic Behaviors of High-Performance Concrete Shear Walls of Rectangular Section

2011 ◽  
Vol 255-260 ◽  
pp. 2439-2443 ◽  
Author(s):  
Xing Wen Liang ◽  
Jia Liang Kou ◽  
Ming Ke Deng
Keyword(s):  
High Performance ◽  
High Performance Concrete ◽  
Plastic Hinge ◽  
Shear Walls ◽  
Shear Wall ◽  
Wall Structure ◽  
Deformation Capacity ◽  
Damage Level ◽  
Wall Deformation ◽  
Hinge Zone

The paper explores the failure mode, failure mechanism and deformation capacity of medium-high and low-rise shear walls. The experimental results from load-tests of 5 high-performance concrete shear walls with 1.5 and 1.0 shear span ratio indicate that the shear walls deformation capacity benefits from several bar rings like a chain along boundary element in plastic hinge zone, showing that shear wall deformation capacity design is reliable to a certain extent, in that the plastic hinge zone often influences the damage level of shear walls. With the damage at different stages, the paper divides the performance of shear wall structure into three kinds: serviceability, life-safety and collapse-prevention. Accordingly, it is proposed that the performance controlling indicators for shear wall structures is composed of storey drift ratio and the rotation of plastic hinge zone, and also provides consult values for each performance level.

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