Showing papers on "Shear wall published in 2017"

Seismic response of CFS shear walls sheathed with nailed gypsum panels: Experimental tests

Abstract: Among the several available building systems, constructions involving cold-formed steel (CFS) profiles represent an efficient and reliable solution. These systems are very suitable to be used in pre-fabricated modular constructions, thanks to their lightness and possibility to automate the building process. In a framework of the European project ELISSA (Energy Efficient LIghtweight-Sustainable-SAfe-Steel Construction), which was devoted to the development and demonstration of CFS modular systems, an experimental campaign aimed at investigating the seismic response of this system was carried out at University of Naples Federico II. Specifically, the studied system was a sheathing-braced CFS solution, in which the seismic resistant elements were made of CFS stud shear walls laterally braced with gypsum-based panels. The sheathing panels were attached to the CFS frame by means of ballistic nails, whereas clinching points were used for steel-to-steel connections. This paper shows the results of tests performed on shear walls and on the relevant ballistically nailed panel-to-steel connections. In particular, four full scale shear walls were tested, in which the influence of the aspect ratio, the type of loading and the effect of finishing was investigated.

Cyclic Behavior of Replaceable Steel Coupling Beams

Abstract: For improving the seismic resiliency of coupled shear wall systems, a type of replaceable steel coupling beam was developed, which consists of a central “fuse” shear link connecting to steel beam segments at its two ends. Inelastic deformation is concentrated in the shear link during a severe earthquake, and the damaged links can be replaced easily as specialized link-to-beam connections are adopted. This paper presents a series of quasi-static tests conducted to examine the seismic behavior and replaceability of the replaceable coupling beams. A total of four large-scale specimens were designed and tested, where different types of beam-to-link connections were adopted, including end plate, splice plate, bolted web, and adhesive web. All specimens fully developed the shear strength of the fuse links and showed large inelastic rotation capacity of no less than 0.06 rad, except for the specimen with the adhesive web connection, which failed at an early stage. The specimen with the end plate connecti...

In-Plane Stiffness of Cross-Laminated Timber Panels with Openings

Abstract: Cross-laminated timber (CLT) is increasingly being used in residential and nonresidential applications While the quantification of the in-plane stiffness of CLT shear walls is required to design a

Cyclic analyses of corrugated steel plate shear walls

Abstract: Summary Corrugated steel plate shear wall (CoSPSW), which consists of a steel boundary frame and a corrugated steel wall panel with the corrugation in the horizontal or vertical direction, is a new type of lateral load-resisting system in the family of steel plate shear walls. Compared with the unstiffened special plate shear walls (SPSW), CoSPSW would have greater elastic buckling capacity and more resistance to the gravity loads transferred to the wall panel or neatly avoid them, depending on the corrugation direction. The main research contents of this paper is on the cyclic behavior of CoSPSWs and comparison with SPSWs. Nonlinear push-over and cyclic analyses were conducted on a group of CoSPSW and SPSW models, and parametric studies were performed with different panel and frame configuration, as well as gravity load effects. It turns out that CoSPSWs with deep corrugation have higher lateral stiffness, lateral strength, and energy dissipation than SPSWs, whereas CoSPSWs with shallow corrugation have higher lateral stiffness and ductility, but lower lateral strength than SPSWs. For all cases investigated, CoSPSWs have stable hysteric curves with no almost pinching, and they are much less sensitive to the influence of gravity loads or weaker boundary frames, compared to SPSWs.

Experimental Study of Self-Centering Shear Walls with Horizontal Bottom Slits

Abstract: This paper introduces a new design form for prestressed shear walls with horizontal bottom slits utilizing cast-in-place technology. Horizontal slits are placed symmetrically at the wall-foundation interface of prestressed shear walls while the concrete in the middle of the wall width remains connected with the foundation. Furthermore, unbonded prestressed tendons inside the wall are adopted to provide self-centering ability. Tests on prestressed self-centering shear walls with horizontal bottom slits under cyclic loading were conducted to investigate their seismic performance. Test results were analyzed from the tests, and a comparison was made among traditional shear wall and self-centering shear walls with horizontal bottom slits of different configurations. The experimental results indicate that the tested cast-in-place shear walls exhibit excellent self-centering ability with the lateral load capacity similar to traditional shear walls. The quantity and distribution range of the cracking in t...

Experiments and Simulations of Cold-Formed Steel Wall Assemblies Using Corrugated Steel Sheathing Subjected to Shear and Gravity Loads

Abstract: The paper presents experimental and numerical investigation of cold-formed steel (CFS)–framed walls sheathed with corrugated steel sheets. The new wall technology is considered as an alternative shear wall configuration for midrise buildings at strong earthquake and high-wind regions because of its attributes of noncombustibility and higher structural performance than the conventional shear wall types. However, design provisions of such corrugated sheathed CFS-framed shear walls have not been included in the current design standards. To establish comprehensive database information and to observe the performance of the bearing wall for the first time, a test program of full-scale wall assemblies using corrugated steel sheathing was conducted. The test specimens included both shear wall specimens and bearing wall specimens under lateral and vertical/gravity loading. In accordance with the full-scale tests, a numerical model was developed in a computer program, and seismic performance assessment was ...

Test and analysis of a new ductile shear connection design for RC shear walls

Abstract: This paper presents a new and construction-friendly shear connection for the assembly of precast reinforced concrete shear wall elements. In the proposed design, the precast elements have indented interfaces and are connected by a narrow zone grouted with mortar and reinforced with overlapping U-bar loops. Contrary to conventional shear connections, the planes of the U-bar loops are here parallel to the plane of the wall elements. This feature enables a construction-friendly installation of the elements without the risk of rebars clashing. The core of mortar inside each U-bar loop is reinforced with a transverse double T-headed bar to ensure transfer of tension between the overlapping U-bars. Push-off tests show that a significantly ductile load–displacement response can be obtained by the new solution as compared to the performance of the conventional keyed shear connection design. The influence of the interface indentation geometry was investigated experimentally and the failure modes in the push-off tests were identified by use of digital image correlation (DIC). For strength prediction, rigid plastic upper-bound models have been developed with inspiration from the observed failure mechanisms. Satisfactory agreement between tests and calculations has been obtained.

Experimental and numerical investigation of the seismic response of precast wall connections

Abstract: This paper investigates the seismic response of lightly reinforced precast concrete shear walls typically used for low- to mid-rise residential systems in past and current Dutch building practice. The results of a wide set of pseudostatic cyclic tests performed on full-scale single precast panels with or without openings were examined and discussed, quantifying the sensitivity of structural response and failure mode to changes in axial load and wall geometry. Behavioral aspects of those panels were treated at a global/structural and local/sectional level, posing particular emphasis on their wall-to-foundation and wall-to-wall joints. Asymmetric push–pull tests of precast wall connections were also carried out and presented to characterize the cyclic behavior of this type of joint system under simulated seismic loading. The outcome of this large campaign of experimental tests was then used to develop and validate a simple numerical model to be integrated in a framework for large scale seismic fragility analysis of precast terraced structures built with this particular technology.

Experimental study on a new type of earthquake resilient shear wall

Abstract: Summary Reinforced concrete (RC) shear walls have been extensively used as lateral load resisting structural members in tall buildings However, in the past, strong earthquake events RC structural walls in some buildings suffered severe damage, which concentrated at the bottom and was very difficult to be repaired The installation of the replaceable corner components (RCCs) at the bottom of the structural wall is a new method to form an earthquake resilient structural wall whose function can be quickly restored by replacing the RCCs after the strong earthquake because of the damage concentrating on RCCs In this study, a new kind of replaceable energy-dissipation component installed at the bottom corner of RC structural walls was proposed To study the seismic performance of the new structural wall with RCCs, the cyclic loading tests on three new structural wall specimens and one conventional RC structural wall specimen were conducted One of the new structural wall specimens experienced replacement and reloading process to verify the feasibility of replacement The results show that the structural behavior of all specimens was flexure dominating The damage in the new shear specimens mainly concentrated on RCCs The replacement of RCCs can be implemented conveniently after the residual deformation occurred in the structure Compared with the conventional structural wall specimen, the seismic performance of new structural wall specimens was improved significantly Copyright © 2017 John Wiley & Sons, Ltd

Experimental investigation on the behavior of corrugated steel shear wall subjected to the different angle of trapezoidal plate

Abstract: Summary Studies on corrugated steel shear walls (CSSWs) generally indicate noticeable increase of energy absorption, as well as increasing shear buckling capacity of corrugated plates being more likely rather than the flat plates. In this paper, the effect of variation in the angle of trapezoidal plate on the behavior of CSSWs has extensively been investigated. Three specimens of CSSW with 1 story and single bay in half scale are tested under cyclic load. The observations of experiment do indicate that stress concentration has been increased in the corner of subpanels, by increasing of the corrugation angle. Development of the tensile field and wall yield and damage depends on the geometry of the plate. By increasing the corrugation angle, the stiffness and energy dissipation decrease; in addition, large loss of strength takes place. Comparing the numerical and experimental results indicates that for a closer look at behavior of trapezoidal CSSWs, fracture mechanics, fatigue, and damping of materials should be considered by numerical analysis.

Life-cycle cost optimization of the seismic retrofit of existing RC structures

Abstract: The life-cycle cost analysis of buildings prone to seismic risk is a critical issue in structural engineering. Expected loss, including damage and repair costs, is an important parameter for structural design. The combination of economic theory and computer technology allows for a more developed approach to the design and construction of structures than ever before. In this study, a simplified method based on a semi-probabilistic methodology is developed to evaluate the economic performance of a building prone to seismic risk. The proposed approach aims to identify the most cost-effective strengthening strategies and strengthening levels for existing structures during their structural lifetime. To achieve this, the method identifies the optimal strengthening level, computing on the one hand the costs of strengthening the structure at different performance levels for each strategy, and, on the other, the expected seismic loss during the structure’s lifetime. To assess the expected loss, the building is divided into several components, both structural and non-structural. A set of fragility curves is assigned for each component. Then, once the structural model and the various components of the building, with the corresponding fragility curves, are defined, a loss assessment is performed using a static non-linear analysis. The summation of the strengthening costs and the discounted expected losses produces a relationship between the total costs and the strengthening level. The minimum of this relationship identifies the most cost-effective strengthening intervention. As a case study, this method is applied to an existing reinforced concrete (RC) structure severely damaged by the 2009 earthquake in L’Aquila. Different strategies are analyzed, namely the FRP (fiber reinforced polymer) strengthening of elements, the RC jacketing of columns, RC exterior shear wall insertions, and the base isolation of the building.

Structural performance of RC shear walls with post-construction openings strengthened with FRP composite laminates

Abstract: Over the past few decades, retrofitting of existing buildings, rather than new construction, became more popular due to economic reasons and the benefit of shorter service interruptions of constructed facilities. Change of use of an existing building may require the removal of portions of the structural members such as introducing door and window openings in an existing shear walls. In these scenarios, a remedial external retrofit is needed to restore the structural integrity and to regain building’s seismic ductility. This paper presents the results of an experimental study that aimed at evaluating the structural performance of reinforced concrete (RC) shear walls, with different opening geometries strengthened with fiber-reinforced-polymer (FRP) carbon/epoxy composites laminates. Experimental results indicated that the proposed FRP lamination system for RC shear walls with post-construction openings was successful in enhancing both the strength and ductility of retrofitted walls. The average strength gain and ductility enhancement of the retrofitted walls, as compared to the unstrengthened walls ranged from 20% to 28%. An analytical procedures for analyzing retrofitted reinforced concrete with different opening geometries is also presented. For design purposes, a proposed efficiency factor that accounts for the efficiency of different lamination protocols is discussed. Conclusions and recommendations for future research are presented.