Showing papers on "Shear wall published in 2009"

Reinforced Concrete Design of Tall Buildings

Abstract: Design Concept Characteristics of Reinforced Concrete Behavior of Reinforced concrete Elements External Loads Lateral Load-Resisting Systems Collapse Patterns Buckling of a Tall Building under its Own Weight Gravity Systems Formwork Considerations Floor Systems Design Methods One-Way Slab, T-Beams, and Two-Way Slabs: Hand Calculations Prestressed Concrete Systems Foundations Guidelines for Thinking on Your Feet Unit Quantities Lateral Load-Resisting Systems Flat Slab-Frame System Flat Slab-Frame with Shear Walls Coupled Shear Walls Rigid Frame Tube System with Widely Spaced Columns Rigid Frame with Haunch Girders Core-Supported Structures Shear Wall-Frame Interaction Frame Tube System Exterior Diagonal Tube Bundled Tube Spinal Wall Systems Outrigger and Belt Wall System Miscellaneous Systems Wind Loads Design Considerations Natural Wind Characteristics of Wind ASCE 7-05: Wind Load Provisions National Building Code of Canada (NBCC 2005): Wind Load Provisions Wind-Tunnels T Seismic Design Building Behavior Seismic Design Concept An Overview of 2006 IBC ASCE 7-05 Seismic Provisions: An Overview An Overview of Chapter 11 of ASCE 7-05, Seismic Design Criteria An Overview of Chapter 12 of ASCE 7-05, Seismic Design Requirements for Building Structures ASCE 7-05, Seismic Design: An In-Depth Discussion Seismic Design Example: Dynamic Analysis Procedure (Response Spectrum Analysis) Using Hand Calculations Anatomy of Computer Response Spectrum Analyses (In Other Words, What Goes on in the Black Box) Dynamic Response Concept Dynamic Analysis Theory Seismic Design Examples and Details Seismic Design Recap Design Techniques to Promote Ductile Behavior Integrity Reinforcement Review of Strength Design Intermediate Moment-Resisting Frames Special Moment-Resisting Frames Shear Walls Frame Members Not Designed to Resist Earthquake Forces Diaphragms Foundations Design Examples Typical Details ACI 318-08 Update Seismic Rehabilitation of Existing Buildings Code-Sponsored Design Alternate Design Philosophy Code Provisions for Seismic Upgrade Building Deformations Common Defi ciencies and Upgrade Methods Seismic Rehabilitation of Existing Buildings, ASCE/SEI 41-06 Fiber-Reinforced Polymer Systems for Strengthening of Concrete Buildings Seismic Strengthening Details Tall Buildings Historical Background Review of High-Rise Architecture Functional Requirements Definition of Tall Buildings Lateral Load Design Philosophy Concept of Premium for Height Relative Structural Cost Factors for Reduction in the Weight of Structural Frame Development of High-Rise Architecture Structural Scheme Options Summary of Building Technology Structural Concepts Bending and Shear Rigidity Index Case Studies Future of Tall Buildings Special Topics Damping Devices for Reducing Motion Perception Seismic Isolation Passive Energy Dissipation Preliminary Analysis Techniques Torsion Performance-Based Design Wind Deflections References Index

Uncertainty and Sensitivity Analysis of Damage Identification Results Obtained Using Finite Element Model Updating

Abstract: A full-scale seven-story reinforced concrete shear wall building structure was tested on the UCSD- NEES shake table in the period October 2005-January 2006. The shake table tests were designed so as to damage the building progressively through several historical seis- mic motions reproduced on the shake table. A sensitivity- based finite element (FE) model updating method was used to identify damage in the building. The estimation uncertainty in the damage identification results was ob- served to be significant, which motivated the authors to perform, through numerical simulation, an uncertainty analysis on a set of damage identification results. This study investigates systematically the performance of FE model updating for damage identification. The dam- aged structure is simulated numerically through a change in stiffness in selected regions of a FE model of the shear wall test structure. The uncertainty of the identified damage (location and extent) due to variability of five input factors is quantified through analysis-of-variance

Special Perforated Steel Plate Shear Walls with Reduced Beam Section Anchor Beams. I: Experimental Investigation

Abstract: This paper presents results of an experimental investigation of specially detailed ductile perforated steel plate shear walls SPSWs designed to accommodate utility passage, and having anchor beams with reduced beam sections connections. Single-story, single-bay SPSW frames are subjected to quasi-static cyclic loading up to their maximum strength and displacement capacity. The tested specimens also had low yield strength steel infill panels. Two specimens make allowances for penetration of the panel by utilities. The first, having multiple holes specially laid out in the steel panel, also has the characteristic of reduced panel strength and stiffness compared to the corresponding SPSW having a solid panel. The second such specimen utilizes quarter-circle cutouts in the panel corners, which are reinforced to transfer the panel forces to the adjacent framing. A SPSW with solid panel is also tested for reference purposes. All specimens resisted an imposed input history of increasing displacements to a minimum drift of 3%. The perforated panel reduced the elastic stiffness and overall strength of the specimen by 15% as compared with the solid panel specimen.

Shear resistance of masonry walls and Eurocode 6: shear versus tensile strength of masonry

Abstract: In the case of masonry structures subjected to seismic loads, shear failure mechanism of walls, characterised by the formation of diagonal cracks, by far predominates the sliding shear failure mechanism. However, as assumed by Eurocode 6, the latter represents the critical mechanism for the assessment of the shear resistance of structural walls. The results of a series of laboratory tests are analysed to show that in the case of the diagonal tension shear failure the results of the Eurocode 6 based calculations are not in agreement with the actual resistance of masonry walls. The results of calculations, where the diagonal tension shear mechanism and tensile strength of masonry are considered as the critical parameters, are more realistic. Since the results of seismic resistance verification, based on the Eurocode 6 assumed sliding shear mechanism, are not in favour of structural safety, it is proposed that in addition to sliding shear, the diagonal tension shear mechanism be also considered. Besides, in order to avoid misleading distribution of seismic actions on the resisting shear walls, the deformability characteristics of masonry at shear should be determined on the basis of experiments and not by taking into account the Eurocode 6 recommended G/E ratio.

Behavior of Double Skin Composite Wall Subjected to In-Plane Cyclic Loading

Abstract: Double skin composite walls are composed of two steel plate "skins" connected by tie bars, with the space between them filled with concrete. They were developed to reduce wall thickness, to enhance constructability, and to enable rapid construction by eliminating the use of formwork and reinforcing bars. In the present study, cyclic testing was performed to investigate the seismic behavior of isolated and coupled double skin composite walls with rectangular and T-shaped cross sections. The wall specimens failed mainly by tensile fracture of the welded joints at the wall base and coupling beams, or by local buckling of the steel plates. Because of their large depth, the ductility of the wall specimens was not as good as that of beams having less depth. In particular, the ductility of the walls was significantly affected by the strengthening methods used for the wall base. The load-carrying capacities of the isolated and coupled wall specimens were evaluated using plastic stress distributions in their cross sections, which provided satisfactory predictions.

Steel Plate Shear Walls with Various Infill Plate Designs

Abstract: An experimental study was performed to investigate the structural capacity of steel plate walls with various infill plate designs. Five three-story steel plate shear walls with thin infill plates were tested. The parameters for this test were the connection method between the boundary frame and the infill plate (welded connection versus bolted connection), length of the welded connection (full connection versus partial connection), and opening in the infill plate (solid wall versus coupled wall). Regardless of the infill plate design, the steel plate wall specimens exhibited excellent strength, deformation capacity, and energy dissipation capacity, although the walls with bolt-connected infill plates exhibited a slightly lower deformation capacity. This result indicates that for architectural reasons and enhancement of constructability, various infill plate designs can be used in practice without a significant reduction in the structural capacity of the steel plate walls. The strength and energy dissipation capacity of the steel plate wall specimens with various infill plate designs were predicted by proposed methods. The prediction results were compared with the test results.

Self-Centering Behavior of Unbonded, Post-Tensioned Precast Concrete Shear Walls

Abstract: Self-centering ability of unbonded post-tensioned precast concrete shear walls has been attributed to the presence of post-tensioning force. However, the experimental results presented in this paper indicate that the post-tensioning force may completely die out during cyclic loading while the walls are able to retain their superior self-centering characteristic. Moreover, the analytical study presented in this article indicates that with proper configuration of end-anchorages for post-tensioned tendons, self-centering of post-tensioned walls can be achieved even when the post-tensioning force vanishes. This study also investigates the effects of tendon layout, tendon end-anchorage configuration, and external vertical load on the self-centering ability of unbonded precast concrete shear walls subjected to earthquake loading.

Health monitoring of reinforced concrete shear walls using smart aggregates

Abstract: In this paper, a smart aggregate-based approach is proposed for the structural health monitoring of a concrete shear wall structure. The piezoceramic-based smart aggregates were distributed in predetermined locations prior to the casting of the concrete structure to form an active-sensing system for the health monitoring purpose. To evaluate the damage in different areas, the concrete shear wall was sectioned into sub-domains and a wavelet-packet-based damage index matrix is proposed to evaluate the health status in these sections. A cyclic loading procedure was applied to gradually fail the concrete shear wall and the proposed structural health monitoring approach was used to perform structural health monitoring during this loading procedure. The experimental results have shown that the proposed smart aggregate-based approach effectively evaluated the damage status in different areas and detected the precautionary point to predict the structural failure. The proposed approach has the potential to be applied to the structural health monitoring of large-scale concrete shear wall structures.

Analysis of Steel Plate Shear Walls Using the Modified Strip Model

Abstract: Unstiffened steel plate shear walls are an effective and economical method of resisting lateral forces on structures due to wind and earthquakes. Structural engineers require the ability to assess the inelastic structural response of steel plate shear walls using conventional analysis software that is commonly available and is relatively simple and expeditious to use. The strip model, a widely accepted analytical tool for steel plate shear wall analysis, is refined based on phenomena observed during loading of steel plate shear walls in the laboratory. Since the original strip model was proposed as an elastic analysis tool, these refinements are made primarily to achieve an accurate representation of yielding and eventual deterioration of the wall, although moderate improvements in initial stiffness predictions are also made. In assessing each of the proposed refinements, modeling efficiency is evaluated against the accuracy of the solution. A parametric study using the modified strip model examines the effect of varying the angle of inclination of the tension strips on the predicted inelastic behavior of the model. Notably, it was found that the ultimate capacities of steel plate shear wall models with a wide variety of configurations vary little with the variation of the inclination of the strips.

Simulation of the shaking table test of a seven-story shear wall building

Abstract: This paper presents the simulation of the nonlinear dynamic response of a full-scale seven-story reinforced concrete shear wall shaking table specimen under base excitations representing four earthquake records of increasing intensity. The study was motivated by the participation in the blind prediction contest of the shaking table specimen organized by University of California at San Diego (UCSD), NEES, and Portland Cement Association (PCA). Owing to the time constraints of the contest a relatively simple two-dimensional (2d) model was used for the shear wall specimen. In this model, the shear wall was represented by 2d beam-column elements with fiber discretization of the cross-section that account for the interaction of the axial force with the bending moment. Upon conclusion of the contest, the available experimental measurements permitted a thorough examination of the analytical results. While the measured data confirmed the excellent accuracy of the model predictions, some limitations also became apparent. The paper addresses the benefits and limitations of the selected modeling strategy and investigates the sensitivity of this type of model to parameter selection.

Shear failure characteristics of steel plate girders

Abstract: A number of full-scale plate girders are modeled and analyzed to determine their shear failure mechanism characteristics. An objective of this numerical nonlinear large deflection elastoplastic finite element study is to clarify how, when, and why plastic hinges that emerge in experimental tests actually form. It is observed that shear-induced plastic hinges only develop in the end panels. These hinges are caused by the shear deformations near supports and not due to bending stresses arising from tension fields. Also, a comparison between the ultimate capacity of various plate girders and different codes and theories is presented. Finally, it is shown that simple shear panels, in the form of detached plates, do not accurately represent the failure mechanism of web plates.

Finite-Element Investigation and Design Recommendations for Perforated Steel Plate Shear Walls

Abstract: This paper presents results from an investigation of the behavior of unstiffened thin steel plate shear wall (SPSW) having a regular pattern of openings (a.k.a. perforated SPSW). Finite element monotonic pushover analyses were conducted, first on a series of individual perforated strips with variation in perforation diameter, to develop a fundamental understanding of the behavior of complete perforated SPSW, then on a corresponding series of complete perforated SPSW having various perforation diameters. Three different sets of wall boundary conditions are considered, namely: flexible beam laterally braced, rigid floor, and rigid beam. Though some differences between the SPSW panel strips and the individual strip results are observed at large monitored strain, at lower monitored strain however the two models are in a good agreement. Based on the analytical results design recommendations of these perforated SPSWs are presented. The shear strength of a SPSW infill plate having a pattern of multiple regularly spaced circular perforations can be calculated as a function of the shear strength of a solid panel, perforation diameter, and distance between perforations.

Special Perforated Steel Plate Shear Walls with Reduced Beam Section Anchor Beams. II: Analysis and Design Recommendations

Abstract: This paper presents a comparison of analytical and experimental results from an investigation of specially detailed ductile perforated steel plate shear walls (SPSWs). These SPSWs had low yield strength steel infill panels, anchor beams with reduced beam sections connections, and were specially detailed to accommodate utility passage through the wall while remaining ductile. Finite-element models of full SPSWs and subelement strips are developed using the finite element software package ABAQUS/Standard to facilitate a comparison with experimental results and to investigate the influence of localized distribution of panel stress and strain between perforations. Based on the analytical and experimental results, recommendations for the design of these special detailed perforated SPSWs are presented.

Development of Nailed Wood Joint Element in ABAQUS

Abstract: Testing showed that the hysteretic behavior of nailed wood joints governs the response of many wood systems when subjected to lateral loadings. Unfortunately, commercially available software does not have the appropriate hysteretic element for a nailed wood joint, and the accuracy and versatility of the previously developed nail joint elements are not satisfactory. A general hysteretic model, Bouc-Wen-Barer-Wen, was modified to represent the hysteretic behavior of a nailed joint, in which the hysteretic constitutive law is characterized by a series of ordinary differential equations. It can produce versatile and smoothly varying hysteresis curves, is nonlinear, history dependent, and includes stiffness and strength degradation, and pinching. Based on the test data, the suitable parameters for different joint configurations can be estimated through genetic algorithms. This model was embedded in commercially available software, ABAQUS/Standard (Version 6.5), as a user-defined element which accounted for the coupling property of the nail joint action. A detailed shear wall was modeled and analyzed, and the results agreed well with the test data.

Analysis of fully anchored light-frame timber shear walls — elastic model

Abstract: In order to stabilize light-framed timber buildings against lateral loads, the diaphragm action of roofs, floors and walls is often used. This paper deals with an elastic analysis model for fully anchored sheathed wood frame shear walls. The model is based on the assumption of a linear elastic load-slip relation for the sheathing-to-framing joints. Only static loads are considered. The basic structural behaviour and assumptions for the elastic model are elucidated. Formulas for the load-bearing capacity and the deformation of the shear walls in the ultimate and serviceability limit states, respectively, are derived. Both a discrete point description and a continuous flow per unit length modelling of the fasteners are discussed. Also, the forces and displacements of the fasteners and sheathing are derived. The effect of different patterns and spacing of the fasteners on the capacity and displacement of the wall is illustrated. The influence of flexible framing members and shear deformations in the sheets, and also the effect of vertical loads on the shear wall, both with respect to tilting and second order effects, on the horizontal load-bearing capacity and displacement are evaluated. The stress distribution and the reaction forces at the ends of the different framing members are derived. The elastic model is experimentally verified and an illustrative example is given.

Nonlinearity in the postbuckling behaviour of thin steel shear panels

Abstract: Buckling of thin steel shear panels is a sudden phenomenon, whereas material yielding is a gradual trend. After buckling, large out-of-plane displacements are formed which induce relatively high bending stresses with significant influences on the postbuckling behaviour of shear panels. At present, design rules are only concerned with critical and ultimate load capacity limit states. This paper discusses the nonlinear postbuckling path of thin shear panels, emphasizing on (i) an intermediate limit state when panels experience first yield points and (ii) the growth pattern of yield zone. It is also observed that the postbuckling behaviour of shear panels is mostly governed with geometrical nonlinearity.

Seismic performance of friction dampers using flexure of rc shear wall system

Abstract: Shear wall systems in high-rise apartments are governed by the flexural behaviour of members such as a cantilever beam. The installation of the damper-brace system in a structure governed by flexural behaviour is not suitable. Because of the relatively high lateral stiffness of the shear wall, a load is not concentrated on the brace and the brace cannot perform the role of a damping device. In this paper, a friction damper that applies the flexibility of a shear wall is proposed in order to reduce the deformation of the structure. To evaluate the performance of the proposed friction damper, a nonlinear time history analysis is executed by the SeismoStruct analysis program, and a multiple vertical linear element model is used for simulating flexural behaviour of the shear wall. It is found that the control performance of the proposed friction damper is superior to that of a coupled wall with a rigid beam. In conclusion, this study verified that the optimal control performance of the proposed friction damper is equal to 45% of the maximum shear force induced in the middle floor beam with the rigid beam. Copyright © 2009 John Wiley & Sons, Ltd.

Design of Steel Plate Shear Walls Considering Boundary Frame Moment Resisting Action

Abstract: Conventional design of steel plate shear walls (SPSWs) assumes that 100% of the story shear is resisted by each infill panel. Following this approach, strength provided by the boundary frame moment resisting action, which provides the SPSW with overstrength, is neglected. While this design assumption has a positive impact on seismic performance of SPSWs, no analytical work has been done to quantify the magnitude of this overstrength in general terms. Such preliminary work is conducted in this paper. Based on plastic analysis of SPSWs, this paper investigates the relative and respective contributions of boundary frame moment resisting action and infill panel tension field action to the overall plastic strength of SPSWs, followed by a proposed procedure to make use of the strength provided by the boundary frame moment resisting action. Procedures for design of SPSWs having weak infill panels are also developed in this paper. Then, results from a series of time history analyses using validated models are presented to compare the seismic performances of SPSWs designed using different design assumptions. Future work needed to provide greater insight on SPSW designs is also identified.

Coupled shear-bending formulation for seismic analysis of stacked wood shear wall systems

Abstract: A summary of the development of a new coupled shear-bending model for analysis of stacked wood shear walls and multi-story wood-frame buildings is presented in this paper. The model focuses on dynamic response of light-frame wood structures under seismic excitation. The formulation is intended to provide a more versatile option than present pure shear models in that the new model is capable of accurately capturing the overall lateral response of each story diaphragm and separates the inter-story shear deformation and the deformation associated with rotation of the diaphragm due to rod elongation, which is an analogue to the bending deformation in an Euler–Bernoulli beam model. Modeling the coupling of bending and shear deformation is shown to provide more accurate representation of stacked shear wall system behavior than a pure shear model, particularly for the upper stories in the assembly. The formulation is coupled with the newly developed evolutionary parameter hysteretic model for wood shear walls. Existing data from a shake table test of an isolated three-story wood shear wall were used to verify the accuracy of the model prediction. The numerical results agreed very well with shake table test measurements. The influence of a continuous rod hold-down system on the dynamic behavior of the three-story stacked wood shear wall was also successfully simulated. Copyright © 2009 John Wiley & Sons, Ltd.