Showing papers on "Shear wall published in 2016"

Multifractal analysis of crack patterns in reinforced concrete shear walls

Abstract: Conventionally, the assessment of reinforced concrete shear walls relies on manual visual assessment which is time-consuming and depends heavily on the skills of the inspectors. The development of ...

Cyclic performance of precast concrete shear walls with a mortar–sleeve connection for longitudinal steel bars

Abstract: To study the cyclic performance of precast concrete shear walls with a mortar–sleeve connection for longitudinal steel bars, a quasistatic test on shear wall specimens with flexure failure modes was carried out The longitudinal steel bars in the precast concrete walls were connected with a steel sleeve using mortar Test results indicated that the mortar–sleeve splicing effectively transferred the stresses on the vertical steel bars The failure mode of the precast shear wall specimens had similar behaviors to that of the cast-in-place shear wall specimen, including the tensile yielding of the longitudinal steel bars and the crushing of the concrete in the compressive zone The stiffness and energy dissipation capacity of the precast wall specimens were less than those of the cast-in-place wall specimen The ultimate drift ratio of the precast wall specimens ranged from 169 to 208 % The integrity of the precast shear walls with a vertical rough interface was better than that of the precast shear walls with a vertical step groove

Experimental Seismic Response of a Full-Scale Cold-Formed Steel-Framed Building. II: Subsystem-Level Response

Abstract: The objective of this paper is to employ the results from the extensive instrumentation installed on recently tested full-scale cold-formed steel (CFS)-framed buildings to reveal a deeper understanding of the behavior of the building under seismic excitations. In particular, this paper complements a companion paper that focuses on system-level design and response. Here, utilizing strategically located string potentiometers, strain gauges, and accelerometers, the responses of the walls and diaphragms are isolated from the overall building response and studied. The interaction of shear walls along a wall line, as well as across stories is studied through measured data on strains in hold-down anchors, strains on floor-to-floor strap connecting shear-wall chord studs, and displacements across shear-wall sheathing and openings. The behavior of the floor diaphragm is studied through displacements measured perpendicular to the plane of one wall of the building and accelerometers throughout the floor of t...

Performance Control and Efficient Design of Rocking-Wall Moment Frames

Abstract: Rocking-wall moment frames (RWMFs) are unique, lateral resisting structures in which the shear wall pivots about its pinned base rather than act as a fixed base, upright cantilever. The function of the wall is to prevent soft-story failure, reduce drift concentration, and provide suitable supports for energy-dissipating devices. However, despite their favorable seismic performance, their practical design aspects have not been fully addressed in the literature. This paper proposes a new approach based on the principles of design-led analysis. It provides a lucid study of the analytic components and inner workings of RWMFs as efficient lateral resisting systems. While complementing existing literature on the subject, this study presents several interesting findings and useful design conclusions. For instance, it points out that under certain circumstances, neither the rocking wall nor its appendages can influence the ultimate carrying capacity of the frame. The proposed solutions are entirely suitab...

Experiments on seismic behaviour of steel sheathed cold-formed steel shear walls cladded by gypsum and fiber cement boards

Abstract: In this paper experiments are presented to investigate the seismic response of steel sheathed cold-formed steel (CFS) shear walls using gypsum and fiber cement board claddings. Six steel sheathed wall specimens of various cladding configurations were tested under cyclic loading. The use of claddings at either or both sides of the walls results in an increase of their lateral stiffness, shear strength and energy dissipation capacity by up to 67, 80% and 76%, respectively. On the use of claddings connected to the CFS walls their effects on the shear strength must be incorporated into the current design specifications for an efficient and safe design.

Performance of cold-formed-steel-framed shear walls sprayed with lightweight mortar under reversed cyclic loading

Abstract: Sheathing with sprayed lightweight mortar (SLM) is proposed to enhance the performance of shear walls framed with cold-formed steel (CFS). Full-scale specimens were tested to assess the failure mode, strength, stiffness, ductility, and energy absorption achieved. Slippage between the CFS framing and the SLM significantly increased the walls’ strength and stiffness and restricted crack propagation. The failure mode typically involves local buckling of the end studs. Specimens with SLM on the front and calcium silicate boards (CSBs) on the back were weaker than specimens with SLM sheathing on both sides. Joint-strengthened knee elements or X-shaped steel-strap bracings increased the load-bearing capacity and reduced the ductility of the specimens.

Analytical model based on artificial neural network for masonry shear walls strengthened with FRM systems

Abstract: In the future Fiber Reinforced Polymer (FRP) materials will be considered a common strengthening system for civil structures thanks to several research efforts made in the last decades. For those applications in which FRP materials show some restrictions such as, above all, the incompatibility with heritage buildings, a new generation of fibrous materials has been developed. Researchers have investigated Fiber Reinforced Mortars (FRM) as external structural and seismic reinforcement. One of the most attractive applications of these materials is related to the in-plane shear strength of masonry walls. In this scenario, an analytical model based on Artificial Neural Network (ANN) is proposed and discussed in respect of the geometrical and mechanical variables that control the mechanical problem. An ANN is presented in the paper by showing its possible productive application in the civil engineering field. The proposed model seems able to predict the shear strength of FRM strengthened masonry; the approach is considered efficient since it includes both a theoretical method and a large test calibration, illustrated herein. Thanks to a quite small input database of laboratory results, ANN seems able to provide a theoretical solution to the problem with accuracy and precision.

Experimental Study of the Lateral Resistance of Bolted Glulam Timber Post and Beam Structural Systems

Abstract: To study the lateral resistance of bolted glued-laminated (glulam) timber post and beam structures, two monotonic tests and eight cyclic tests were performed on full-scale, one-story, one-bay timber post and beam construction specimens. Four laterally strengthened structural systems were considered: a frame with an X-brace, a frame with a K-brace, a frame with a knee-brace, and a frame filled with light wood shear walls. Seismic performances were evaluated according to the experimental phenomena, hysteretic characteristics, stiffness degradation, strength degradation, and energy dissipation capacity. The results showed that the frame with an X-brace system and the frame with a K-brace system provided markedly better elastic stiffness but lower ductility. The frame with a knee-brace system showed increased elastic stiffness compared with the simple frame system and provided higher ductility compared with both the frame with the X-brace system and the frame with the K-brace system. Additionally, the...

Ductility Estimation for a Novel Timber–Steel Hybrid System

Abstract: In current force-based seismic design procedures, structures are allowed to behave inelastically during significant seismic events. For this reason, the applied design base shear of a structure is calculated by reducing the elastic strength demand by a ductility factor that represents the ability of a structure or structural system to deform inelastically beyond yielding. Whereas North American building codes provide ductility factors for traditional structural systems, including timber-based or steel-based systems, there are currently no design provisions available for novel hybrid structural systems. Thus research is required to define the force reduction factors, and specifically the ductility factor, Rd, to safely and efficiently design novel systems within the existing seismic design provisions. One such novel system is the so-called finding the forest through the trees (FFTT), proposed in 2012, where mass-timber panels act as shear walls and are connected to each other and to perimeter frame...