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This paper presents an experimental investigation into the flexural behaviour of masonry walls that have been reinforced using near-surface mounted (NSM) or externally bonded (EB) reinforcement, under out-of-plane loading. The study simulates retrofitting applications and also proposes the NSM technique for new wall construction, using pre-grooved blocks, in lieu of the conventional method of internal reinforcing and grouting. To accommodate the NSM reinforcement, the grooves in the masonry blocks were aligned with ducts used to anchor the NSM reinforcement in the concrete footing. Seven wall specimens were tested, including walls reinforced with conventional and stainless steel bars, glass fibre-reinforced polymer (GFRP), and carbon FRP (CFRP) reinforcement. The study demonstrated the feasibility and effectiveness of the NSM technique for new construction. Walls with NSM reinforcement showed a superior performance to those with EB reinforcement. It was shown that increasing the FRP reinforcement ratio may result in a change of failure mode, and as such, the increase in strength may not be proportional to the increase in reinforcement ratio. NSM steel reinforced walls showed a superior performance in terms of strength, stiffness and the ductility associated with the formation of a plastic hinge at the base. [ABSTRACT FROM AUTHOR]

The recently-released Australian Concrete Standard, AS3600-2009, has been extensively revised with particular emphasis on the inclusion of design rules for high-strength concrete. For the simplified design of axially-loaded concrete walls, the guidelines have been changed to include new effective height factors for different support conditions and to allow for higher concrete strengths. Initially the updated guidelines and scope of the simplified equation are provided. Load capacity predictions using the simplified method are then evaluated against a number of test results obtained from recent research. Finally, a typical case study is presented to illustrate the extended scope of the new rules. [ABSTRACT FROM AUTHOR]

The article reflects on the design procedures for a hybrid wall system located at the University of California at San Diego in California, proposed by the Precast Seismic Structural Systems (PRESSS) research program. It focuses on the development of a design charts for the wall system that can eliminate the need of long calculations. It mentions that the hybrid wall system consists of two or more precast concrete wall panels which are connected by special shear connectors.

Abstract: Low aspect ratio reinforced concrete walls are widely used in buildings and infrastructure to provide resistance to earthquake shaking. Future performance assessment of such structures, which will focus on repair cost and business interruption rather than component checking per ASCE 41, will utilize fragility functions that relate the probability of exceeding one or more damage thresholds to an efficient response (demand) parameter. Fragility functions are developed here for low aspect ratio reinforced concrete walls to enable future performance assessment of buildings and other structures incorporating these common structural components. The functions are developed by review and statistical evaluation of data from tests of rectangular, barbell and flanged walls. Story drift is used as the demand parameter. Experimental data are interpreted using damage states and methods of repairs. Documents that provide guidelines for repair of reinforced concrete walls, observations from experimental programs, previous research on retrofit of reinforced concrete walls, and expert opinion are used to identify the most appropriate damage states and their corresponding methods of repair. Damage states are characterized in most instances by direct indicators of damage such as cracking and crushing of concrete cracking, residual displacements due to sliding, and reinforcement buckling and fracture. Each of these damage states is linked with one of four methods of repair in increasing order of repair cost, namely, cosmetic repair, epoxy injection, partial wall replacement, and wall replacement. An ordered sequence of fragility functions is provided for each wall cross section. The statistical evaluation of the data do not support the development of fragility surfaces to accommodate widely used design variables such as axial force, rebar ratio and aspect ratio. [ABSTRACT FROM AUTHOR]

Abstract: Composite concrete barriers represent a good alternative to current landfill containment systems because they can be made using waste minerals and thus have a lower environmental and economic cost. They are also more robust when in place. This paper presents results from laboratory testing and site trials and modelling of a concrete barrier system. Laboratory trials to determine the effect of cracking on the composite barrier are also reported. It is concluded that cracking will not cause failure. The modelling of the transport processes provided a good prediction of the movement of some species in the site trials. [Copyright &y& Elsevier]

Abstract: Cost-effectiveness evaluations for soil retaining structures require better knowledge of the integrity and serviceability of these structures subjected to foundation settlements. As a preliminary study on the performance-based design of soil retaining structures that takes into account the influence of foundation settlements, the settlement-tolerating characteristics of cantilever soil retaining walls (CWs) placed on deformable foundations were explored using a 0.6 m-high model cantilever wall backfilled with rhombically stacked 1.96 mm uniform diameter steel rods used as two-dimensional backfills of the wall. Screw jacks were used to simulate a non-yielding foundation and three types of spring with various spring constants were used to simulate deformable foundations with maximum foundation settlements of approximately 2%, 5%, and 9% of the total wall height. It was found that the measured values of the lateral pressure coefficient (K f) increased significantly with a decrease of subgrade stiffness, k v (or an increase of maximum foundation settlement, S max). The measured values of K f for the CWs placed on deformable ground may be greater than those for the at-rest (K o) condition when S max is greater than 3% of the total height of the wall (H t). For the tested cantilever wall with moderately high safety factors against sliding and overturning based on a commonly adopted assumption of an unyielding foundation, significant decreases in safety factors associated with the increase in S max were observed. Equations for additional margins of design lateral pressure coefficient and/or safety factors against sliding and overturning for the wall, expressed as a function of maximum foundation settlement, are proposed to substantiate the safety evaluation of soil retaining walls situated on a deformable foundation. [Copyright &y& Elsevier]

Addition of urea-based antifreeze admixtures during cement mixing in construction of buildings has led to increasing indoor air pollution due to continuous transformation and emission of urea to gaseous ammonia in indoor concrete wall. In order to control ammonia pollution from indoor concrete wall, the aqueous dispersion was firstly prepared with nano-scale TiO2 photocatalysts and dispersing agent, and then mixed with some textile additives to establish a treating bath or coating paste. Cotton woven fabrics were used as the support materials owing to their large surface area and large number of hydrophilic groups on their cellulose molecules and finished using padding and coating methods, respectively. Two TiO2-loaded fabrics were obtained and characterized by X-ray diffractometer (XRD) and scanning electron microscopy (SEM). Moreover, a specifically designed ammonia photocatalytic system consisting of a small environmental chamber and a reactor was used for assessing the performance of these TiO2-loaded fabrics as the wall cloth or curtains used in house rooms in the future and some factors affecting ammonia decomposition are discussed. Furthermore, a design equation of surface catalytic kinetics was developed for describing the decomposition of ammonia in air stream. The results indicated that increasing dosage of the TiO2 aqueous dispersion in treating bath or coating paste improved the ammonia decomposition. And ammonia was effectively removed at low ammonia concentration or gas flow rate. When relative humidity level was 45%, ammonia decomposition was remarkably enhanced. It is the fact that ammonia could be significantly decomposed in the presence of the TiO2-padded cotton fabric. Whereas, the TiO2-coated cotton fabric had the reduced photocatalytic decomposition of ammonia and high adsorption to ammonia owing to their acrylic binder layer. Finally, the reaction rate constant k and the adsorption equilibrium constant K values were determined through a curve-fitting method and the TiO2-padded cotton fabric had the higher k value and lower K value than the TiO2-coated cotton fabric. [Copyright &y& Elsevier]

Empirical wall design equations provided in major codes of practice are conservative because they do not cover walls that are supported on all four sides or walls with slenderness ratios greater than 30. They do not cover walls that require openings for doors, windows and services. The recognition of such factors in design codes would result in savings in construction costs. This study investigates the effect of side restraints and the presence of openings for reinforced concrete wall panels where axial load eccentricity induces secondary bending. A numerical analysis of such walls is undertaken using the non-linear Layered Finite Element Method (LFEM), and results are compared with eight one-third to one-half scale wall panels tested previously at Griffith University. The LFEM predicts the failure loads, the load-deflection responses, the deformed shapes and the crack patterns of the tested wall panels. Subsequent parametric studies on the ultimate load carrying capacity of 54 one-way and two-way reinforced concrete walls with openings established relationships of failure load with slenderness ratio and eccentricity. [ABSTRACT FROM AUTHOR]

Tilt-up concrete wall construction is an alternative to cast-in-place, precast, or masonry methods of constructing building walls. The process involves more than just a cast and lift operation. Detailed planning, preparation, scheduling, and safety issues are constantly redefining the process. This paper describes the tilt-up process in step-by-step detail from the panel layout, to the setting of forms, to the concrete placement, and finally to the panel erection. A warehouse/office/shop tilt-up in Tempe, Ariz. is used as a case history of this construction method. [ABSTRACT FROM AUTHOR]

The article reviews a project for a photo sensible concrete which will display the trajectory of the light coming through the windows of a room.

Load-carrying capacity of confined masonry walls in the out-of-plane direction after being damaged is crucial for overall stability and is affected by the type of interface present at the wall edge and column, such as toothing. Shake table tests were conducted to investigate the effectiveness of a toothed connection on the out-of-plane behavior of damaged confined masonry walls. Four half-scale clay brick masonry walls were subjected to a sequence of slow cyclic in-plane drifts and shake table-generated ground motions in the out-of-plane direction. Specimens included one regular RC infill frame and three confined masonry panels, two with different densities of toothing and one with no toothed connection. The specimen with the infill panel demonstrated a higher risk of out-of-plane collapse, whereas the other three confined masonry wall specimens maintained structural integrity and out-of-plane stability even when severely damaged. The confined masonry walls with or without toothing enhanced the interaction between masonry walls and RC confining elements and were able to delay the failure by controlling out-of-plane deflections even after an in-plane drift cycle of 1.75%. [ABSTRACT FROM AUTHOR]

New reinforced concrete (RC) walls are popular in seismic rehabilitation of RC buildings as they reduce seismic-deformation demands. Their effectiveness was experimentally investigated by pseudodynamically testing scaled models of three four-story frames infilled with RC. The specimens were considered part of a frame building, the rest of which was substructured in the test as elastic. Unlike in past tests, the wall web was not thinner than the frame members and the specimens were tall enough to be governed by flexure. Two code-conforming designs were tried for the connection of the web to the surrounding frame members, one of them being less labor-intensive. Behavior and failure were dominated by flexure, but open, u-shaped FRP jackets at the two edges of the composite wall were essential to prevent premature failure near the base because of poor detailing of the columns. Slippage/separation at interfaces between the web and surrounding frame members was minor for both connection details. In one specimen the critical plastic hinge did not form at the base but instead in a horizontal band defined by the first-story beam of the frame, in which the vertical beam stirrups were much weaker than the vertical wall reinforcement; however, this did not adversely affect the global energy-dissipation and deformation capacity. The values of the secant-to-yield-point stiffness, yield moment, and ultimate chord rotation of the composite walls inferred from the tests are in good overall agreement with expressions given in international codes for monolithic walls with the same geometry, reinforcement, and detailing. [ABSTRACT FROM AUTHOR]