Scholarly

Capacity of Anchors in Structural Connections

Year: 2013 Volume: 7 Issue: 4 333 - 337 Pages

Abstract: When dealing with safety in structures, the connections between structural components play an important role. Robustness of a structure as a whole depends both on the load- bearing capacity of the structural component and on the structures capacity to resist total failure, even though a local failure occurs in a component or a connection between components. To avoid progressive collapse it is necessary to be able to carry out a design for connections. A connection may be executed with anchors to withstand local failure of the connection in structures built with prefabricated components. For the design of these anchors, a model is developed for connections in structures performed in prefabricated autoclaved aerated concrete components. The design model takes into account the effect of anchors placed close to the edge, which may result in splitting failure. Further the model is developed to consider the effect of reinforcement diameter and anchor depth. The model is analytical and theoretically derived assuming a static equilibrium stress distribution along the anchor. The theory is compared to laboratory test, including the relevant parameters and the model is refined and theoretically argued analyzing the observed test results. The method presented can be used to improve safety in structures or even optimize the design of the connections

Solar Panel Installations on Existing Structures

Year: 2013 Volume: 7 Issue: 4 327 - 332 Pages

Authors:
Tim D. Sass
Pe
Leed

Abstract: The rising price of fossil fuels, government incentives and growing public aware-ness for the need to implement sustainable energy supplies has resulted in a large in-crease in solar panel installations across the country. For many sites the most eco-nomical solar panel installation uses existing, southerly facing rooftops. Adding solar panels to an existing roof typically means increased loads that must be borne by the building-s structural elements. The structural design professional is responsible for ensuring a new solar panel installation is properly supported by an existing structure and configured to maximize energy generation.

Traces of Birdhouse Tradition in Anatolia

Year: 2013 Volume: 7 Issue: 4 320 - 326 Pages

Abstract: The birdhouses and dovecotes, which are the indicator of naturalness and human-animal relationship, are one of the traditional cultural values of Turkey. With their structures compatible with nature and respectful to humans the bird houses and dovecotes, which have an important position in local urbanization models as a representative of the civil architecture with their unique form and function are important subjects that should be evaluated in a wide frame comprising from architecture to urbanism, from ecologic agriculture to globalization. The traditional bird houses and dovecotes are disregarded due to the insensitivity affecting the city life and the change in the public sense of art. In this study, the characteristic properties of traditional dovecotes and birdhouses, started in 13th century and ended in 19th century in Anatolia, are tried to be defined for the sustainability of the tradition and for giving a new direction to the designers.

Instability of Ties in Compression

Year: 2013 Volume: 7 Issue: 4 315 - 319 Pages

Authors:
T. Cornelius

Abstract: Masonry cavity walls are loaded by wind pressure and vertical load from upper floors. These loads results in bending moments and compression forces in the ties connecting the outer and the inner wall in a cavity wall. Large cavity walls are furthermore loaded by differential movements from the temperature gradient between the outer and the inner wall, which results in critical increase of the bending moments in the ties. Since the ties are loaded by combined compression and moment forces, the loadbearing capacity is derived from instability equilibrium equations. Most of them are iterative, since exact instability solutions are complex to derive, not to mention the extra complexity introducing dimensional instability from the temperature gradients. Using an inverse variable substitution and comparing an exact theory with an analytical instability solution a method to design tie-connectors in cavity walls was developed. The method takes into account constraint conditions limiting the free length of the wall tie, and the instability in case of pure compression which gives an optimal load bearing capacity. The model is illustrated with examples from praxis.

Improving Carbon Sequestration in Concrete: A Literature Review

Year: 2013 Volume: 7 Issue: 4 312 - 314 Pages

Abstract: Due to urbanization, trees and plants which covered a great land mass of the earth and are an excellent carbon dioxide (CO2) absorber through photosynthesis are being replaced by several concrete based structures. It is therefore important to have these cement based structures absorb the large volume of carbon dioxide which the trees would have removed from the atmosphere during their useful lifespan. Hence the need for these cement based structures to be designed to serve other useful purposes in addition to shelter. This paper reviews the properties of Sodium carbonate and sugar as admixtures in concrete with respect to improving carbon sequestration in concrete.

Structural Cost of Optimized Reinforced Concrete Isolated Footing

Year: 2013 Volume: 7 Issue: 4 304 - 311 Pages

Authors:
Mohammed S. Al-Ansari

Abstract: This paper presents an analytical model to estimate the cost of an optimized design of reinforced concrete isolated footing base on structural safety. Flexural and optimized formulas for square and rectangular footingare derived base on ACI building code of design, material cost and optimization. The optimization constraints consist of upper and lower limits of depth and area of steel. Footing depth and area of reinforcing steel are to be minimized to yield the optimal footing dimensions. Optimized footing materials cost of concrete, reinforcing steel and formwork of the designed sections are computed. Total cost factor TCF and other cost factors are developed to generalize and simplify the calculations of footing material cost. Numerical examples are presented to illustrate the model capability of estimating the material cost of the footing for a desired axial load.

Blast Induced Ground Shock Effects on Pile Foundations

Year: 2013 Volume: 7 Issue: 4 299 - 303 Pages

Abstract: Due to increased number of terrorist attacks in recent years, loads induced by explosions need to be incorporated in building designs. For safer performance of a structure, its foundation should have sufficient strength and stability. Therefore, prior to any reconstruction or rehabilitation of a building subjected to blast, it is important to examine adverse effects on the foundation caused by blast induced ground shocks. This paper evaluates the effects of a buried explosion on a pile foundation. It treats the dynamic response of the pile in saturated sand, using explicit dynamic nonlinear finite element software LS-DYNA. The blast induced wave propagation in the soil and the horizontal deformation of pile are presented and the results are discussed. Further, a parametric study is carried out to evaluate the effect of varying the explosive shape on the pile response. This information can be used to evaluate the vulnerability of piled foundations to credible blast events as well as develop guidance for their design.

Dynamic Performance Indicators for Aged-Care Construction Projects

Year: 2013 Volume: 7 Issue: 4 294 - 298 Pages

Abstract: Key performance indicators (KPIs) are used for post result evaluation in the construction industry, and they normally do not have provisions for changes. This paper proposes a set of dynamic key performance indicators (d-KPIs) which predicts the future performance of the activity being measured and presents the opportunity to change practice accordingly. Critical to the predictability of a construction project is the ability to achieve automated data collection. This paper proposes an effective way to collect the process and engineering management data from an integrated construction management system. The d-KPI matrix, consisting of various indicators under seven categories, developed from this study can be applied to close monitoring of the development projects of aged-care facilities. The d-KPI matrix also enables performance measurement and comparison at both project and organization levels.

Numerical Simulation of Progressive Collapse for a Reinforced Concrete Building

Year: 2013 Volume: 7 Issue: 4 290 - 293 Pages

Abstract: Though nonlinear dynamic analysis using a specialized hydro-code such as AUTODYN is accurate and useful tool for progressive collapse assessment of a multi-story building subjected to blast load, it takes too much time to be applied to a practical simulation of progressive collapse of a tall building. In this paper, blast analysis of a RC frame structure using a simplified model with Reinforcement Contact technique provided in Ansys Workbench was introduced and investigated on its accuracy. Even though the simplified model has a fraction of elements of the detailed model, the simplified model with this modeling technique shows similar structural behavior under the blast load to the detailed model. The proposed modeling method can be effectively applied to blast loading progressive collapse analysis of a RC frame structure.

Thermal and Mechanical Properties of Basalt Fibre Reinforced Concrete

Year: 2013 Volume: 7 Issue: 4 286 - 289 Pages

Authors:
Tumadhir M.
Borhan

Abstract: In this study, the thermal and mechanical properties of basalt fibre reinforced concrete were investigated. The volume fractions of basalt fibre of (0.1, 0.2, 0.3, and 0.5% by total mix volume) were used. Properties such as heat transfer, compressive and splitting tensile strengths were examined. Results indicated that the strength increases with increase the fibre content till 0.3% then there is a slight reduction when 0.5% fibre used. Lower amount of heat conducted through the thickness of concrete specimens than the conventional concrete was also recorded.

Parametric Optimization of Hospital Design

Year: 2013 Volume: 7 Issue: 4 277 - 285 Pages

Abstract: Present paper presents a parametric performancebased design model for optimizing hospital design. The design model operates with geometric input parameters defining the functional requirements of the hospital and input parameters in terms of performance objectives defining the design requirements and preferences of the hospital with respect to performances. The design model takes point of departure in the hospital functionalities as a set of defined parameters and rules describing the design requirements and preferences.

Sustainable and Ecological Designs of the Built Environment

Year: 2013 Volume: 7 Issue: 4 269 - 276 Pages

Abstract: This paper reviews designs of the built environment from a sustainability perspective, emphasizing their importance in achieving ecological and sustainable economic objectives. The built environment has traditionally resulted in loss of biodiversity, extinction of some species, climate change, excessive water use, land degradation, space depletion, waste accumulation, energy consumption and environmental pollution. Materials used like plastics, metals, bricks, concrete, cement, natural aggregates, glass and plaster have wreaked havoc on the earth´s resources, since they have high levels of embodied energy hence not sustainable. Additional resources are consumed during use and disposal phases. Proposed designs for sustainability solutions include: ecological sanitation and eco-efficiency systems that ensure social, economic, environmental and technical sustainability. Renewable materials and energy systems, passive cooling and heating systems and material and energy reduction, reuse and recycling can improve the sector. These ideas are intended to inform the field of ecological design of the built environment.

International Journal of Architectural, Civil and Construction Sciences

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