Double Brick Research Articles

Estimating the Seismic Strength of Infill Walls by Means of Hollow Brick Prism Tests

Architectural infill walls interact with the surrounding reinforced concrete load bearing members of the building under lateral earthquake loads and can change the system behavior significantly. Therefore, lateral strength calculation of these walls may become mandatory for the designers. These infill walls often formed with horizontally-hollow clay based bricks in many regions of the world. However, strength of these bricks depends on the loading direction and bricks remain in the diagonal compression strut of an infill wall are subjected to biaxial compression. Thus, testing procedures investigate the strength only in the direction perpendicular to the bed-joint seems insufficient to reflect actual behavior. Accordingly, it is confusing for designers to determine or consider compressive strength of hollow clay bricks in order to model and calculate the strength of an infill wall. To clear up this confusion, the seismic strength of plastered infill walls made up of horizontally-hollow bricks were tried to be estimated by various prism tests. The effects of loading direction, plaster, and presence of a single or double brick on prism strength were experimentally investigated. Six reference walls and more than 170 prism specimens were tested in accordance with this scope. The correlation between prism and infill wall strength was established with a valid and practical method. Results showed that diagonally loaded plastered prism group successfully and adequately estimated the experimental infill wall strength. In addition, if diagonal testing is not possible to conduct, the average strength of the vertically and horizontally loaded prism tests may be used instead.

Energy conservation assessment of traditional and modern houses in Sydney

ABSTRACT This study simulates various residential housing construction scenarios, including improved and standard fibro, brick veneer, double brick and fibro with improved flooring. The total heating and cooling energy requirements for each scenario are simulated with a computer program to determine which one is most energy efficient. In the simulation models, construction types and passive solar and energy efficient design strategies (PSEEDS) were varied while other parameters such as wall and roof thickness, windows sizes and general layout were kept constant. The study shows that a standard fibro house had the highest cooling and heating energy requirements (30,721 kWh/yr). The improved reverse brick veneer house had the lowest energy requirement of 9,628 kWh/yr. Amongst all the construction scenarios, the total energy required for cooling was higher than that required for heating. The results show that improved brick veneer, reverse brick veneer and double brick houses have the lowest net energy requirements for heating and cooling compared to the corresponding standard houses. The results indicate that the thermal mass (measured by R value) and PSEEDS incorporated in the construction have significant impact on the energy consumption. Incorporating these design features in the construction of a house can reduce the heating and cooling energy requirements by as much as 69%.

Life-Cycle Assessment of Alternative Envelope Construction for a New House in South-Western Europe: Embodied and Operational Magnitude

The building envelope is critical to reducing operational energy in residential buildings. Under moderate climates, as in South-Western Europe (Portugal), thermal operational energy may be substantially reduced with an adequate building envelope selection at the design stage; therefore, it is crucial to assess the trade-offs between operational and embodied impacts. In this work, the environmental influence of building envelope construction with varying thermal performance were assessed for a South-Western European house under two operational patterns using life-cycle assessment (LCA) methodology. Five insulation thickness levels (0–12 cm), four total ventilation levels (0.3–1.2 ac/h), three exterior wall alternatives (double brick, concrete, and wood walls), and six insulation materials were studied. Insulation thickness tipping-points were identified for alternative operational patterns and wall envelopes, considering six environmental impact categories. Life-cycle results show that, under a South-Western European climate, the embodied impacts represent twice the operational impact of a new Portuguese house. Insulation played an important role. However, increasing it beyond the tipping-point is counterproductive. Lowering ventilation levels and adopting wood walls reduced the house life-cycle impacts. Cork was the insulation material with the lowest impact. Thus, under a moderate climate, priority should be given to using LCA to select envelope solutions.

Rc Infilled Frame: Shaking Table Tests on a Full Scale Model

Tests on shaking table have been carried out on a 3D full scale infilled r.c. frame specimen (55 tons). These tests have been performed by the EMSI Laboratory of C.E.A. Saclay (France) together with a research team of the Universities of Chieti-Pescara (Italy), Roma Tre (Italy) and Patras (Greece). These tests are included in Ecoleader European research program. Many characterization tests of infill components (mortar and bricks) have been performed in the SCAM Laboratory of the University of Chieti-Pescara while tests on masonry walls were made in the laboratory of University of Rome 3. The structure represents the first floor of a two floors frame structure previously tested. The mockup is a full-scale one storey rc infilled frame with four columns, 3 meters high, with about 4 meters side square floor and infilled with double bricks wall. The main aim is to get information about the behavior of real structures. The instrumentation with about one hundred channels was set up to measure the rc frame response and the different behavior of the double walls during the tests. First, monodirectional and bidirectional tests at low seismic intensity (0.10 g and 0.15 g PGA levels) have been performed on the bare frame in order to characterize its structural characteristics and to check the design provisions. Then, the bare frame has been infilled and other tests have carried out at increasing seismic intensity in order to define its serviceability and ultimate limit states. Monodirectional and bidirectional tests up to 0.45 g PGA level were carried out. The last sequence included a monodirectional test on the infilled frame with only two walls. The high seismic input (0.55 g PGA level) was parallel to the direction of the walls. In this paper, research program and some main test results are presented.

Acquisition/Processing—A world of reality—Designing land 3D programs for signal, noise, and prestack migration—Part 2

This article is the continuation of a two-part tutorial. The first part (October, 2004) reviewed methods of estimating signal and understanding noise in a given project area, discussed the concepts of trace density and statistical diversity, and addressed concepts in prestack migration. This part begins with a brief discussion of the merits of various model types, which will lead to a discussion of robustness during implementation. The tutorial concludes by suggesting a data simulation method to evaluate the characteristics of a survey design. Much discussion about survey design has focused around the potential advantages of different survey geometries or model types (orthogonals, staggered orthogonals, bricks, diagonals, etc.). When compared using fixed source and receiver densities, Cooper and Herrera (2002) found very little difference amongst many of these variations. By focusing on limited statistics (for example nearest contributing offset in each bin), differences can be presented that favor some designs over others. However, when other statistics are presented (for example, the gap from nearest to second nearest offsets) the preferences often reverse. I have attempted to study the various common models using more generalized statistics as well as data simulations. The model types were divided into two classes: orthogonal designs (rigid orthogonal, offset orthogonal and staggered orthogonal) and diagonal designs (double brick, triple brick, skewed diagonals, rotated diagonals). I concluded that there were some clear benefits within each category. The staggered orthogonal design showed less bin-to-bin erratic behavior (refer to the offset homogeneity histograms at the top of Figure 14 and the azimuth homogeneity histograms at the top of Figure 15). Similarly, the 26.56° skewed diagonal design exhibited somewhat better statistics than related brick patterns, but the differences between the best of the orthogonal class (the staggered orthogonal) and the best of the diagonal class (the 26.56° skewed) were very subtle. …

The generality of architectural isomerism in designer inclusion frameworks.

We describe herein new structural isomers of a lamellar host system based on organodisulfonate "pillars" that connect opposing hydrogen-bonded sheets, consisting of topologically complementary guanidinium (G) ions and sulfonate (S) groups, to generate inclusion cavities between the sheets. These new isomers-zigzag brick, double brick, V-brick, and crisscross bilayer-expand significantly on our earlier report of architectural isomerism displayed by the discrete bilayer and simple brick forms. We demonstrate here that the discrete bilayer-simple brick isomerism, which was limited to several host-guest combinations based on the G(2)(4,4'-biphenyldisulfonate) host and one pair of compounds based on the G(2)(2,6-naphthalenedisulfonate), can be generalized to other organodisulfonate pillars. Furthermore, in many cases the selectivity toward the different framework isomers reflects a rather systematic templating role of the guest molecules and host-guest recognition during assembly of the lattice. We also describe a convenient approach to identifying and classifying the innumerable possible host architectures based upon the pillar projection topologies for the GS sheets and the intersheet connectivities. The discovery of these new architectures reveals a structural versatility for this class of materials that exceeds initial expectations and observations. Each topology produces different connectivities between the sheets in the third dimension that endows each framework isomer with uniquely shaped and sized inclusion cavities, enabling this host system to conform readily to different guests. The unlimited number of architectures available, combined with the inherent conformational softness and structural tunability of these host lattices, suggests a near universality for the GS system with respect to guest inclusion.