Showing papers on "Shear wall published in 2015"

Cyclic Behavior of CLT Wall Systems: Experimental Tests and Analytical Prediction Models

Abstract: An experimental program was performed at IVALSA Trees and Timber Institute on single and coupled cross-laminated (CLT) wall panels with different anchoring systems and different types of joints between adjacent panels. The mechanical properties of CLT walls were assessed and are critically discussed in the paper. The connector layout and the design of the screwed vertical joints were found to markedly affect the overall behavior of the structural system. The in-plane deformations of CLT panels were almost negligible, whereas concentration of forces and deformations mainly occurred in the connections. Advanced analytical models for nonlinear pushover analysis of CLT wall systems were developed and verified against test results. The models take into account all stiffness and strength components of connectors, as well as the bending and shear deformation of the panels. A parametric study of CLT wall systems with different aspect ratios and wall segmentation was performed, showing that segmentation of...

Cyclic performance of cold-formed steel shear walls sheathed with double-layer wallboards on both sides

Abstract: To satisfy the requirements of fire resistance and loading capacity of the walls in multi-story cold-formed steel (CFS) structures, shear walls sheathed with double-layer wallboards on both sides were proposed. Sheathing materials in these walls included gypsum wallboard (GWB), bolivian magnesium board (BMG) and calcium silicate board (CSB). Cyclic loading tests on six full-scale walls of this configuration were conducted, from which the shear performance of the walls could be obtained. Factors such as the sheathing material, aspect ratio, stud section and stud spacing were considered. Another experimental study on the shear behavior of the screw connections was also performed to explore the potential relationship between the walls and the screw connections in shear performance. The results showed that the peak strength of the walls sheathed with bolivian magnesium boards as the face layer wallboards significantly exceeded the nominal value of the current standard. However, for the walls sheathed with calcium silicate boards as the face layer wallboards, the tested walls exhibited brittleness damage with poor ductility after the peak strength. The equivalent-bracing model was used to calculate the lateral stiffness of the walls, based on which a series of screw connection deformation limits and shear-wall drift angle limits was suggested.

Experimental Characterization of Monotonic and Cyclic Loading Responses of CLT Panel-To-Foundation Angle Bracket Connections

Abstract: Cross laminated timber (CLT) is an engineered wood plate product suitable for the construction of shear walls in low-rise and medium-rise residential and commercial buildings. CLT shear walls are attached to foundations by using metal connectors arranged to prevent the horizontal sliding and uplift of entire superstructures. It is critical that individual CLT panels remain properly anchored, even during events such as design level wind storms and earthquakes, and that overloaded connectors attaching walls to foundations are capable of deforming plastically. This paper presents an experimental investigation of the mechanical behaviors of a range of commercially manufactured and specially designed steel angle bracket connectors intended to resist horizontal shear force flow at CLT wall and foundation interfaces. Both monotonic loading and fully reversed displacement controlled loading protocols were employed so that results apply to wind and seismic design scenarios. The broad conclusion is that the...

Experimental investigation on stiffened steel plate shear walls with two rectangular openings

Abstract: One of the most important advantages of steel plate shear wall (SPSW) is to create openings with different sizes and arbitrary locations on the infill plate depending on their application. In this research, the effects of two openings on the structural behavior of SPSWs were studied experimentally. Experimental testing was performed on three one-third scaled single-story SPSW specimens with two rectangular openings under quasi-static cyclic loading. The differences between the three perforated experimental specimens were the interval between two openings and their closeness to the frame columns. The structural parameters of perforated specimens were compared to the similar specimen without any opening. The experimental results were utilized (a) to compare the ultimate shear strength, stiffness and energy absorption of specimens; (b) to evaluate the performance of central, lateral, top and bottom panels; (c) to investigate the effect of distance between the openings and the columns on the formation of plastic hinges on the column flanges; (d) to study the behavior of stiffeners around the openings. Test results showed that the ultimate shear strength, stiffness and energy absorption were the same in all three perforated specimens and the interval between the two openings had no effect on these values. Moreover, existence of openings will lead to reduction in values of structural parameters.

Seismic behaviour of traditional timber frame walls: experimental results on unreinforced walls

Abstract: Timber frame buildings are well known as an efficient seismic resistant structure and they are used worldwide Moreover, they have been specifically adopted in codes and regulations during the XVIII and XIX centuries in the Mediterranean area These structures generally consist of exterior masonry walls with timber elements embedded which tie the walls together and internal walls which have a timber frame with masonry infill and act as shear walls In order to preserve these structures which characterize many cities in the world it is important to better understand their behaviour under seismic actions Furthermore, historic technologies could be used even in modern constructions to build seismic resistant buildings using more natural materials with lesser costs Generally, different types of infill could be applied to timber frame walls depending on the country, among which brick masonry, rubble masonry, hay and mud The focus of this paper is to study the seismic behaviour of the walls considering different types of infill, specifically: masonry infill, lath and plaster and timber frame with no infill Static cyclic tests have been performed on unreinforced timber frame walls in order to study their seismic capacity in terms of strength, stiffness, ductility and energy dissipation The tests showed how in the unreinforced condition, the infill is able to guarantee a greater stiffness, ductility and ultimate capacity of the wall

Structural Behaviour of Composite Members with Recycled Aggregate Concrete - an Overview

Abstract: A series of investigations on structural behaviour, durability, fire-resistance and seismic performance of composite members with recycled aggregate concrete (RAC) have been carried out in the past 10 years (2005–2014). This paper is consisted of three parts: the first part introduces and discusses the research progress in regard to the structural behaviour of RAC filled steel tubular columns and beams; the second part concentrates on the structural behaviour of steel-reinforced RAC members, including columns, beams, shear walls and slabs; and the third part focuses on the long-term performance of composite members with RAC, involving fire resistance, durability and seismic performance. It seems that RAC composite members with different replacement ratios of recycled coarse aggregate have slightly lower or similar structural behaviour compared to that of normal concrete composite members. Review results reveal that it is feasible to apply steel-RAC composite members as structural applications. This intens...

Seismic Performance of Cold-Formed Steel Wall Systems in a Full-Scale Building

Abstract: This paper presents the seismic performance of two types of cold-formed steel wall systems as characterized during a full-scale five-story building shake table test program: (1) an exterior architectural facade, which spanned the lower three levels of the building, and (2) interior partition wall systems distributed at all levels of the building. The test building was subjected to a suite of earthquake input motions of increasing intensity, first while the building was isolated at its base, and subsequently while it was fixed to the shake table platen. This paper presents the observed physical and measured responses for the two cold-formed steel wall systems and in particular associates physical damage states with measured drift demands in the building. The tests illustrate damage mechanisms for cold-formed steel wall systems when used in architectural facades and highlights areas that should be given particular consideration during seismic design.

Experimental work on single and double-sided steel sheathed cold-formed steel shear walls for seismic actions

Abstract: Experimental investigation is presented on cold-formed steel (CFS) shear walls comprising single and double-sided steel sheathing. Cyclic loading tests were performed on six CFS wall specimens. The observed predominant failure modes include sheathing buckling, sheathing-to-frame connection bearing/tilting and chord stud buckling. The walls developing sheathing connection failure show higher energy dissipation than the walls imposing chord stud buckling. Using double-sided sheathings increases the energy dissipation, shear strength and elastic stiffness by up to 70%, 63% and 115%, respectively compared to those of single-sided sheathed walls. On the use of sheathing on both sides the chord stud failure must be avoided.

Elastic buckling behavior of steel trapezoidal corrugated shear walls with vertical stiffeners

Abstract: This paper investigates the elastic buckling behavior of steel trapezoidal corrugated shear walls (STCSWs) with vertical stiffeners. On the basis of an orthotropic plate model, by utilizing the theorem of minimum potential energy and the Ritz method, the buckling loads of stiffened STCSWs can be precisely calculated using MATLAB. Then, a value of transition rigidity of stiffener is suggested and, hence formulas of elastic buckling coefficients of stiffened STCSWs are proposed. Finally, the verification of proposed formulas using a FE model shows that the formulas are validated and applicable in estimating the elastic buckling loads of stiffened STCSWs.

Experimental Validation of Viscoelastic Coupling Dampers for Enhanced Dynamic Performance of High-Rise Buildings

Abstract: A new damping system, the viscoelastic coupling damper (VCD), has been developed to enhance the wind and seismic performance of coupled shear wall high-rise buildings by adding high damping elements in place of reinforced concrete coupling beams. VCDs replace structural members, such as outriggers or coupling beams, and therefore do not occupy any usable architectural space. When they are properly configured in high-rise buildings, they provide supplemental viscous damping to all lateral modes of vibration, which mitigates building tenant vibration perception problems and reduces both the wind and earthquake response. Experimental results from tests on five small-scale viscoelastic (VE) damper specimens of 5- and 10-mm thicknesses are first presented, followed by the results from six full-scale VCDs representing two alternative configurations. The first was designed for areas where moderate seismic ductility is required, and the second was designed with built-in ductile structural fuses for areas ...

Optimal placement of steel plate shear walls for steel frames by bat algorithm

Abstract: SUMMARY Layout optimization of steel frames with steel plate walls (SPWs) using a meta-heuristic search algorithm is the main aim of the present study. SPWs are lateral load-resisting systems, especially against earthquake excitation. These systems offer significant advantages in terms of cost, performance and ease of design compared with other systems. In this study, orthotropic membrane model is used to model the behaviour of steel plate shear walls. The newly developed bat algorithm, which is based on the echolocation behaviour of bats, is employed as the present study optimizer. Design variables of the optimization problem consist of the cross sections of beams and columns of the frame, the web plate thicknesses of SPWs and the placement of SPW in the frame. The bat algorithm performs suitable selection of sections from the AISC wide-flange (W) shapes list. Strength constraints of the American Institute of Steel Construction Load and Resistance Factor Design and displacement constraints are checked during the optimization process. The results reveal the effectiveness of the proposed method for optimization of steel frames with SPWs. Copyright © 2014 John Wiley & Sons, Ltd.

Seismic behavior of steel sheathed cold-formed steel shear wall: Experimental investigation and numerical modeling

Abstract: Cold-formed steel (CFS) shear wall with steel sheathing is one of the lateral load resisting systems in light steel frame (LSF) construction industry In recent years, several experimental studies have been conducted on the performance of CFS shear walls with one sided steel sheathing However, there are little studies regarding the structural performance of CFS shear walls with double sided steel sheathing or thicker steel sheathing This paper reports the results of an experimental and numerical study that has been conducted on steel sheathed CFS shear wall panels The steel sheathing thickness and the number of the layers of sheathings are the parameters, considered in this study Of particular interests were the specimens' maximum lateral load capacity and failure modes Three physical tests have been conducted to study the performance of different CFS shear walls Also, Non-linear Finite Element Analyses have been performed in order to investigate the seismic behavior of steel sheathed CFS shear wall panels Geometric and material non-linearities were included in the finite element models The numerical model presented here are verified based on the tests results A comparison between the numerical simulations and the test results shows a good agreement between the results of the numerical studies and the test results so the developed finite element models can confidently be used to predict the lateral behavior of steel sheathed CFS shear wall panels

Behavior of stiffened and unstiffened steel plate shear walls considering joint properties

Abstract: Steel plate shear wall (SPSW) systems have dual characteristics, the frame and infill wall action. The connection flexibility of frame joint not only changes the force and moment distribution, but also increases the lateral displacement and weakens the overall stability in SPSW structure. This paper presents the influence of hinged, rigid and semi-rigid connection joints on the behavior of SPSW structures. The bearing capacity, energy dissipation mechanism, failure mode, stress and deformation development process of the semi-rigid composite frame with steel plate shear walls under different stiffener forms were studied using experimental tests and finite element analysis. It was observed that with stiffeners the specimen yield load increased about 20% on the elastic stage, the ultimate bearing capacity of the diagonal stiffener was about 5% larger than the cross stiffener on the plastic stage, but the overall failure modes were basically the same. Additionally, the quantitative indications of the effect of joint stiffness on load carrying capacity were presented.

Behaviour factor for innovative massive timber shear walls

Abstract: Four massive wooden shear walls were analysed via experimental tests and numerical simulations. The specimens differ mainly in the method used to assemble the layers of timber boards: two of them are the well-known Cross-Laminated-Timber panels with glued interfaces, the other two are innovative massive timber panels adopting steel staples or wooden dovetail inserts to connect the layers. Quasi-static cyclic-loading tests were performed for each wall and main results are presented and analysed. A non-linear numerical model was calibrated on experimental results and used to perform non-linear dynamic analyses on specifically designed three-storey shear wall. The methods ensuring a reliable estimation of the intrinsic behaviour factor are presented and the definition of yielding and failure condition is discussed. The intrinsic behaviour factor values were calculated using results from non-linear dynamic analyses. Three limits of failure condition were analysed to estimate the correlated Peak Ground Acceleration and therefore the behaviour factor. A final interpretation of the obtained results is presented and some instructions about the choice of the suitable behaviour factor are given.

Progressive collapse resistance of two typical high-rise RC frame shear wall structures

Abstract: Existing research on progressive collapse of building structures mainly focuses on concrete and steel frame structures. To investigate the progressive collapse resistance of high-rise RC frame shear wall structures, two typical 15-story building models are designed with equivalent overall lateral resistance to seismic actions. However, the structural layouts in resisting the lateral forces are quite different for the two buildings. Building A is a weak wall-strong frame structure, whereas building B is a strong wall-weak frame system. Three-dimensional (3D) finite-element models of the two structures are established using fiber beam and multilayer shell elements. The progressive collapse resistances of the frames and the shear walls in both structures are evaluated under various column (shear wall) removal scenarios. Results demonstrate that there is a difference in progressive collapse prevention performance for different structural layouts. The progressive collapse resistance tends to be inadequ...

Numerical evaluation: AISI S400 steel-sheathed CFS framed shear wall seismic design method

Abstract: Seismic design provisions for steel-sheathed cold-formed steel framed shear walls, specific to Canada, are not provided in the existing AISI S213 Standard “North American Standard for Cold-Formed Steel Framing – Lateral Design”. A multi-phase approach was adopted in order to develop appropriate seismic design provisions for inclusion in the new AISI S400 Standard “North American Standard for Seismic Design of Cold-Formed Steel Structural Systems”. The approach included the extensive displacement based testing and dynamic testing of shear walls, the analysis of the test data results, the development and calibration of dynamic numerical models in OpenSees, and lastly, the dynamic response history analyses of twelve archetype buildings designed for the seismic hazard in three cities; Halifax (low seismic), Montreal (medium seismic) and Vancouver (high seismic). It is this last phase of the study that is documented herein. Fragility curves were developed from the buildings' response to 44 scaled ground motion records following a method adapted from the FEMA P695 analysis methodology. The results showed that the design method is appropriate, including the seismic force modification factors of Rd=2 and Ro=1.3. Improvement to the predicted seismic response of CFS framed buildings could be forthcoming if one were to account for the contribution of the non-structural gypsum wall panels.