Showing papers on "Shear wall published in 2011"

Design and Measured Behavior of a Hybrid Precast Concrete Wall Specimen for Seismic Regions

Abstract: This paper presents the measured behavior from the testing of a 0.4-scale “hybrid” precast concrete wall specimen under reversed-cyclic lateral loading and provides an assessment of the seismic design and analysis of the wall by using the experimental results. The hybrid precast wall system investigated in the paper utilizes a combination of mild (i.e., Grade 400) steel and high-strength unbonded posttensioning (PT) steel for lateral resistance across horizontal joints. A seismic design procedure that conforms to ACI 318 and ACI ITG-5.2 was used for the design of the test specimen based on ACI ITG-5.1. The behavior of the specimen was measured with conventional data acquisition techniques and also full-field digital image correlation of the base panel and the critical joint between the base panel and the foundation, providing unprecedented information on the wall performance. The paper compares these measurements with the design and analytical predictions, focusing specifically on the applied lateral load...

Homogeneous Shear, Wall Slip, and Shear Banding of Entangled Polymeric Liquids in Simple-Shear Rheometry: A Roadmap of Nonlinear Rheology

Abstract: The recent particle-tracking velocimetric (PTV) observations revealed that well-entangled polymer solutions and melts tend to either exhibit wall slip or assume an inhomogeneous state of deformation and flow during nonlinear rheological measurements in simple-shear rheometric setups. Many material parameters and external conditions have been explored since 2006, and a new phenomenological picture has emerged. In this Perspective, we not only point out the challenges to perform reliable rheometric measurements but also discuss the relation between wall slip and internal (bulk) cohesive breakdown and summarize all available findings in terms of a phase diagram. This map specifies the conditions under which shear homogeneity, interfacial slip, and bulk shear inhomogeneity would prevail. The paper is closed by enumerating a number of unresolved questions for future studies.

Shear deformations of slender reinforced concrete walls under seismic loading

Abstract: Experimental results gained from quasi-static cyclic tests on 34 slender structural reinforced concrete walls available in the literature are used to examine the shear deformations for displacement demands in the inelastic range. Based on these results the distribution of shear strains within the walls and the variation of shear deformations with top displacements is discussed. It is shown that for shear walls whose shear transfer mechanism is not deteriorating significantly the ratio of shear to flexural deformations remains approximately constant over the entire range of imposed displacement ductilities while for walls whose shear transfer mechanism is degrading significantly the ratio of shear to flexural deformations is increasing. For the former a simple model is proposed which allows estimating the ratio of shear to flexural deformations.

Behavior of steel plate shear wall connected to frame beams only

Abstract: This paper presents the study of steel plate shear walls which are connected to frame beams only. As the shear walls are not connected to frame columns, the premature failure overall buckling or local buckling of frame columns can be prevented. In fact, most of both structural design engineers and architects prefer this kind of steel plate shear walls because the dimension of their opening space is relatively flexible by using several steel plates with small span-to-height ratio placed parallel to each other. In this paper, two steel plate shear walls were fabricated and tested. The influence of stiffeners on the hysteretic behavior of this kind of member was studied. The experimental results showed that this kind of specimen had good ductility and energy dissipation capacity. The energy dissipation capacity of specimen with stiffeners was larger than that of the specimens without stiffeners. Meanwhile, the finite element method was applied to analyze the behavior of steel plate shear walls, whose results were validated by comparing with the corresponding experimental results. Analytical results showed that the free edges deformed with evident out-of-plane deformation and should be constrained by stiffeners to meet the design requirements. The energy dissipation capacity is much better for steel plate shear walls with lower height-to-thickness ratio and larger span-to-height ratio. At last, the skeleton curve of steel plate shear wall was proposed for calculating the elastic rigidity and load-carrying capacity.

Experimental investigation of composite shear walls under shear loadings

Abstract: One of the efficient methods for improving the seismic behaviour of high-rise buildings is using Composite Steel Plate Shear Wall (CSPSW). In this paper, extensive experimental studies of one and three-story CSPSWs with the scale of 1:3 and 1:4, together with stress equations of each element are reported. The experimental results indicate that this system has reliable behaviour if the columns have high bending stiffness. Also bolts spacing to plate thickness ratio has direct relationship with system ductility. However, plate yield load has an inverse relationship with this ratio. In this system, plate stiffening requirement is obtained with minimum reinforcement for reinforced concrete, though for damage prevention high strength concrete is preferred. Also, the results show a good agreement for the recommended values of (b/t) by an AISC code for preventing plate buckling.

High performance non-combustible gypsum-cement compositions with enhanced water durability and thermal stability for reinforced cementitious lightweight structural cement panels

Abstract: Structural cement panel for resisting transverse and shear loads equal to transverse and shear loads provided by plywood and oriented strain board, when fastened to framing for use in shear walls, flooring and roofing systems. The panels provide reduced thermal transmission compared to other structural cement panels. The panels employ one or more layers of a continuous phase resulting from curing an aqueous mixture of calcium sulfate alpha hemihydrate, hydraulic cement, coated expanded perlite particles filler, optional additional fillers, active pozzolan and lime. The coated perlite has a particle size of 1-500 microns, a median diameter of 20-150 microns, and an effective particle density (specific gravity) of less than 0.50 g/cc. The panels are reinforced with fibers, for example alkali-resistant glass fibers. The preferred panel contains no intentionally added entrained air. A method of improving fire resistance in a building is also disclosed.

New Concept of Structural Seismic Design:Earthquake Resilient Structures

Abstract: Earthquake resilient structure is a new branch of the seismic structural design.The new structural system is not only capable of preventing from the structure failure so as to protect people's life safety during an earthquake,but also restoring immediately the structural function after an earthquake.A research was made of several kinds of resilient structures such as replaceable structure,rocking wall,rocking frame and self-centering structure.The paper presents a summary of the recent research on different kinds of resilient structures,and also a new replaceable technology for coupled shear wall,replaceable coupling beam and replaceable shear wall toe.

Experimental investigation of thin steel plate shear walls with different infill-to-boundary frame connections

Abstract: To make direct comparisons regarding the cyclic behavior of thin steel plate shear walls (TSPSWs) with different infill-to-boundary frame connections, two TSPSWs were tested under quasi-static conditions, one having the infill plate attached to the boundary frame members on all edges and the other having the infill plate connected only to the beams. Also, the bare frame that was used in the TSPSW specimens was tested to provide data for the calibration of numerical models. The connection of infill plates to surrounding frames was achieved through the use of self-drilling screws to fish plates that were welded to the frame members. The behavior of TSPSW specimens are compared and discussed with emphasis on the characteristics important in seismic response, including the initial stiffness, ultimate strength and deformation modes observed during the tests. It is shown that TSPSW specimens achieve significant ductility and energy dissipation while the ultimate failure mode resulted from infill plate fracture at the net section of the infill plate-to-boundary frame connection after substantial infill plate yielding. Experimental results are compared to monotonic pushover predictions from computer analysis using strip models and the models are found to be capable of approximating the monotonic behavior of the TSPSW specimens.

Solution of Shear Wall Location in Multi­Storey Building

Abstract: Shear wall systems are one of the most commonly used lateral-load resisting systems in high-rise buildings. Shear walls have very high in-plane stiffness and strength, which can be used to simultaneously resist large horizontal loads and support gravity loads, making them quite advantageous in many structural engineering applications. There are lots of literatures available to design and analyse the shear wall. However, the decision about the location of shear wall in multi-storey building is not much discussed in any literatures. In this paper, therefore, main focus is to determine the solution for shear wall location in multi-storey building based on its both elastic and elasto-plastic behaviours. An earthquake load is calculated and applied to a building of fifteen stories located in zone IV. Elastic and elasto-plastic analyses were performed using both STAAD Pro 2004 and SAP V 10.0.5 (2000) software packages. Shear forces, bending moment and story drift were computed in both the cases and location of shear wall was established based upon the above computations.

Cyclic Loading Test for Reinforced Concrete Frame with Thin Steel Infill Plate

Abstract: An experimental study was performed to investigate the cyclic behavior of walls that are composed of reinforced concrete boundary frames and thin steel infill plates. For this purpose, three-story steel plate infilled walls (SPIW) were tested. The parameters in this test were the reinforcement ratio of the columns and opening in the infill plates. A reinforced concrete infilled wall (RCIW) and a reinforced concrete frame (RCF) were also tested for comparison. The deformation capacity of the SPIW specimens was significantly greater than that of the RCIW specimen, though the specimens exhibited an identical load-carrying capacity. Similar to the steel plate walls with steel boundary frames, the SPIW specimens showed excellent strength, deformation capacity, and energy dissipation capacity. Furthermore, by using the steel infill plates, shear cracking and failure of the column-beam joints were prevented. By using the strip model, the strength and initial stiffness of the SPIW specimens were predicted. The pr...

Seismic strengthening of RC structures with exterior shear walls

Abstract: Vulnerable buildings and their rehabilitation are important problems for earthquake regions. In recent decades the goal of building rehabilitation and strengthening has gained research attention and numerous techniques have been developed to achieve this. However, most of these strengthening techniques disturb the occupants, who must vacate the building during renovation. In this study, a new strengthening alternative for RC structures, namely exterior shear walls, has been experimentally investigated under reversed cyclic loading. Using the proposed technique, it is possible to strengthen structures without disturbing their users or vacating the building during renovation. In this technique, shear walls are installed in parallel to the building’s exterior sides. It has been observed that the usage of exterior shear walls considerably improve the capacity and sway stiffness of RC structures. The experimental results have also been compared and found to be in agreement with the numerical solutions. Post attached exterior shear walls behaved as a monolithic member of the structure. Design considerations for the exterior shear wall-strengthened buildings have also been discussed in the paper.

Evaluation of Modal and Traditional Pushover Analyses in Frame-Shear-Wall Structures

Abstract: Nonlinear static analysis (or pushover analysis) has been widely used in the last decade as a simplified and approximate method to evaluate the structural seismic performance and to estimate inelastic structural responses under severe ground motions. However most currently used pushover procedures with invariant lateral load patterns cannot fully reflect the effect of higher-order modes on structural dynamic responses. To overcome such a problem, a so-called Modal Pushover Analysis (MPA) was proposed based on the modal decoupling response spectrum method where the effect of higher modes was considered. To date, most research on MPA has been focused on frame structures. In engineering practice, however, most medium-to high-rise building structures are in the form of frame-shear-wall. Therefore it is necessary to extend the current research activity to implement the MPA to frame-shear-wall structures. In this study, two reinforced concrete frame-shear-wall structures of 10 and 18 stories are analyzed to eva...

Tests on seismic behavior of pre-cast shear walls with various methods of vertical reinforcement splicing

Abstract: Quasi-static tests of five reinforced concrete shear wall specimens with aspect ratio of 2.25 are introduced in this paper.Among the five specimens,one was cast-in-place wall specimen,and other four were pre-cast wall specimens with different methods of vertical reinforcement splicing.The test results indicate that the failure mode of the pre-cast wall specimens is the same as that of the cast-in-place wall specimen,i.e.,tensile yield of the vertical reinforcements in the boundary elements and compressive failure of concrete at the wall bottom.The sleeve-mortar splicing transfers stresses of vertical reinforcement effectively.The specimen with stirrup splicing has in-plane slide between the pre-cast wall and the cast-in-place part,which has the minimum values of ultimate drift ratio and energy dissipation capacity among the five specimens.The ultimate drift ratios of all specimens are larger than 1/100.The measured compression-flexural strength of the pre-cast wall specimens are larger than the current code calculated value.Based on the test results,recommendations on further studies of pre-cast shear walls are proposed.

Effect of Spacing of Reinforcement on the Behaviour of Partially Grouted Masonry Shear Walls

Abstract: Partially Grouted Reinforced Masonry (PGRM) shear walls perform well in places where the cyclonic wind pressure dominates the design. Their out-of-plane flexural performance is better understood than their inplane shear behaviour; in particular, it is not clear whether the PGRM shear walls act as unreinforced masonry (URM) walls embedded with discrete reinforced grouted cores or as integral systems of reinforced masonry (RM) with wider spacing of reinforcement. With a view to understanding the inplane response of PGRM shear walls, ten full scale single leaf, clay block walls were constructed and tested under monotonic and cyclic inplane loading cases. It has been shown that where the spacing of the vertical reinforcement is less than 2000 mm, the walls behave as an integral system of RM; for spacing greater than 2000 mm, the walls behave similar to URM with no significant benefit from the reinforced cores based on the displacement ductility and stiffness degradation factors derived from the complete later...