دانلود رایگان مقاله لاتین انحنای اسمی ستون hsc از سایت الزویر
عنوان فارسی مقاله:
طراحی انحنای اسمی ستون HSC مدور محدود با تسمه های فلزی پس تنیده
عنوان انگلیسی مقاله:
Nominal Curvature Design of Circular HSC Columns Confined with Post-tensioned Steel Straps
سال انتشار : 2016
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مقدمه انگلیسی مقاله:
1. Introduction
Current design guidelines for reinforced concrete (RC) structures promote the use of strong and yet ductile columns which are able to sustain large deformations without failure. Many of such columns have small cross sections (compared to the column height) and end restraints that do not prevent column sway. These “slender columns” tend to deform laterally when axial load and flexural moment (first order effects) are applied, thus subjecting the columns to additional (second order) moments. Hence, at large lateral deformations, slender columns can experience global buckling and can fail at lower loads compared to those sustained by short columns. To account for the additional second order effects in design, current design codes [e.g. the Chinese Code [5]; Eurocode 2 [3]] calculate the total column eccentricity as the sum of the nominal eccentricity (from first order effects) and the additional eccentricity due to slenderness (second order). When such slenderness effects are accounted for in design, larger column sections are normally required to resist the moment which in turn increase the construction costs. In an attempt to enhance the stiffness and capacity of slender columns (thus reducing sway and second order effects), high-strength concrete (HSC) is extensively utilised nowadays in the design and construction of new RC buildings, particularly in Southeast Asia. While the use of HSC is effective at enhancing the columns' capacity, previous experimental studies [9,13] also showed that HSC columns can fail in a brittle manner, and thus adequate confinement is required to ensure their ductile behaviour. Internal steel ties/stirrups were used in the past to enhance the ductility of HSC columns (e.g. Ma et al. [14], Ho et al. [15]). Nonetheless, the effectiveness of internal stirrups is limited as only the core of the columns' cross section is effectively confined, especially after cover spalling. To increase the effectiveness of the confinement and to prevent spalling, externally bonded Fibre Reinforced Polymer (FRP) wraps were recently proposed as a confining solution for HSC elements (e.g. Idris and Ozbakkaloglu [16]; Lim and Ozbakkaloglu [17]). However, both internal reinforcement and FRP wraps can only provide passive confinement to structural elements. The high initial cost of FRP materials may also discourage their use as confinement solution in low and medium income developing countries. As a result, it is deem necessary to develop more cost-effective confining solutions for HSC columns. Recently, Ma et al. [10] and Lee et al. [8] investigated experimentally the effectiveness of an innovative active confining technique (referred here as Steel Strapping Tensioning Technique or SSTT) at enhancing the capacity of HSC columns. The SSTT involves the post-tensioning of high-strength high-ductility steel straps around RC elements using airoperated strapping tools similar to those utilised in the packaging industry. After the post-tensioning operation, self-regulated end clips clamp the steel straps and maintain the tensioning force. Contrary to internal stirrups or external FRP wraps, the SSTT provides active confinement to the full cross section of members. The SSTT also has additional advantages such as ease and speed of application, ease of removing or replacing steel straps, and low material and labour costs. Whilst previous tests showed that the use of the SSTT can enhance the deformation capacity of HSC columns by a minimum of 50% [10,11], no practical design guidelines exist for new SSTT-confined HSC columns so that the confining technique can be widely adopted in practice. This article proposes new parameters for the practical design of circular high-strength concrete (HSC) columns confined with an innovative Steel Strapping Tensioning Technique (SSTT) using a nominal curvature approach. To achieve this, the proposed design approach uses results from segmental analyses of slender SSTT-confined columns subjected to eccentric loads. The results obtained from the analyses are used to determine the basic parameters that govern the design of such columns. The proposed nominal curvature approach is validated using experimental results available in the literature. The practical design approach proposed in this study is expected to contribute towards a wider use of the costeffective SSTT in new HSC structures by providing guidelines that can reduce considerably the computational time during design.
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کلمات کلیدی:
Nominal Curvature Design of Circular HSC Columns ... - ScienceDirect www.sciencedirect.com/science/article/pii/S2352012416300078 by CK Ma - 2016 - Cited by 5 - Related articles Apr 13, 2016 - This article proposes new parameters for the practical design of circular high-strength concrete (HSC) columns confined with an innovative Steel Strapping Tensioning Technique (SSTT) using a nominal curvature approach. ... The proposed design approach is based on results from ... Nominal Curvature Design of Circular HSC Columns ... - Structures www.structuresjournal.org/article/S2352-0124(16)30007-8/abstract by CK Ma - 2016 - Cited by 5 - Related articles Abstract. This article proposes new parameters for the practical design of circular high-strength concrete (HSC) columns confined with an innovative Steel ... Nominal Curvature Design of Circular HSC Columns Confined with ... https://cee.sheffield.ac.uk/.../nominal-curvature-design-circular-hsc-columns-confined... Nominal Curvature Design of Circular HSC Columns Confined with Post-tensioned Steel Straps. Authors. Ma CK, Awang AZ, Garcia R, Omar W, Pilakoutas K, ... [PDF]Nominal Curvature Design of Circular HSC Columns Confined with ... civil.utm.my/.../Nominal-Curvature-Design-of-Circular-HSC-Columns-Confined-with.... Apr 13, 2016 - Nominal Curvature Design of Circular HSC Columns Confined with. Post-tensioned Steel Straps. Chau Khun Ma a,⁎, Abdullah Zawawi Awang ... Nominal Curvature Design of Circular HSC Columns Confined with ... civil.utm.my/.../nominal-curvature-design-of-circular-hsc-columns-confined-with-post-t... Nominal Curvature Design of Circular HSC Columns Confined with Post-tensioned Steel Straps – pdf. Posted on August 9, 2016 ·. Nominal Curvature Design of ... Nominal Curvature Design of Circular HSC Columns Confined with ... civil.utm.my/.../nominal-curvature-design-of-circular-hsc-columns-confined-with-pos... Nominal Curvature Design of Circular HSC Columns Confined with Post-tensioned Steel Straps. Posted on August 9, 2016 ·. Filed Under: Journal Papers ... Research paper: Nominal Curvature Design of Circular HSC Columns ... https://www.researchgate.net/.../301303208_Nominal_Curvature_Design_of_Circular_H... Dec 29, 2016 - Download academic paper (PDF): Nominal Curvature Design of Circular HSC Columns Confined with Post-tensioned Steel Straps on ... Flexural ductility design of confined high-strength concrete columns ... https://www.researchgate.net/.../283813941_Flexural_ductility_design_of_confined_hig... Flexural ductility design of confined high-strength concrete columns: Theoretical modelling ... Nominal Curvature Design of Circular HSC Columns Confined with ...
