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  1. Article ; Online: Performance of Concentrically Loaded RC Wall-like Columns Upgraded with Innovative Hybrid NSM/CFRP System.

    Elsanadedy, Hussein / Abbas, Husain / Almusallam, Tarek / Al-Salloum, Yousef

    Polymers

    2023  Volume 15, Issue 2

    Abstract: In RC (reinforced concrete) frame structures, wall-like columns are laid within the space occupied by masonry walls to maximize usable space and thus minimize the column projections into the usable area. These columns often require strengthening owing to ...

    Abstract In RC (reinforced concrete) frame structures, wall-like columns are laid within the space occupied by masonry walls to maximize usable space and thus minimize the column projections into the usable area. These columns often require strengthening owing to various reasons, including increasing the number of stories, changes in building usage, and others. The use of a hybrid system comprising NSM (near-surface mounted) steel rebars combined with CFRP (carbon-fiber reinforced polymer) laminates may be considered a sound technique for strengthening such wall-like building columns. The prime aim of this study is to devise an efficient scheme using a hybrid NSM/CFRP system to strengthen existing RC wall-like columns. Six half-scale RC wall-like columns were prepared and tested under monotonic concentric axial compression. Two columns were unstrengthened to serve as control specimens (CW1 and CW2), and four specimens were strengthened using four different schemes (SW1, SW2, SW3, and SW4). As favored by architects, all strengthening schemes were designed so that the dimensions of the column cross-section were not increased. The effects of strengthening schemes on the enhancement of axial capacity, energy dissipated, and stiffness were evaluated to find the most efficient scheme. Among the four studied schemes, using vertical continuous NSM rebars in combination with the wrapping of the three CFRP layers onto the exterior column surface (in specimen SW2) was the most efficient as it enhanced the ultimate load capacity by 80%. Three-dimensional FE (finite element) analysis was also conducted to predict the response of test specimens. The test results matched well with the FE outputs, which justified the accuracy of the used constitutive models for concrete, steel rebars, and CFRP sheets.
    Language English
    Publishing date 2023-01-10
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2527146-5
    ISSN 2073-4360 ; 2073-4360
    ISSN (online) 2073-4360
    ISSN 2073-4360
    DOI 10.3390/polym15020378
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article ; Online: Hybrid Steel/NSM/GFRP System versus GFRP Wrapping for Upgrading RC Wall-like Columns.

    Elsanadedy, Hussein / Abbas, Husain / Siddiqui, Nadeem / Almusallam, Tarek / Al-Salloum, Yousef

    Polymers

    2023  Volume 15, Issue 8

    Abstract: Reinforced concrete (RC) wall-like columns are commonly employed in structures in Saudi Arabia. These columns are preferred by architects owing to their minimum projection in the usable space. However, they often need strengthening due to several reasons, ...

    Abstract Reinforced concrete (RC) wall-like columns are commonly employed in structures in Saudi Arabia. These columns are preferred by architects owing to their minimum projection in the usable space. However, they often need strengthening due to several reasons, such as the addition of more stories and increasing the live load as a result of changing the usage of the building. This research aimed to obtain the best scheme for the axial strengthening of RC wall-like columns. The challenge in this research is to develop strengthening schemes for RC wall-like columns, which are favored by architects. Accordingly, these schemes were designed so that the dimensions of the column cross-section are not increased. In this regard, six wall-like columns were experimentally examined in the event of axial compression with zero eccentricity. Two specimens were not retrofitted to be used as control columns, whereas four specimens were retrofitted with four schemes. The first scheme incorporated traditional glass fiber-reinforced polymer (GFRP) wrapping, while the second one utilized GFRP wrapping combined with steel plates. The last two schemes involved the addition of near-surface mounted (NSM) steel bars combined with GFRP wrapping and steel plates. The strengthened specimens were compared with regard to axial stiffness, maximum load, and dissipated energy. Besides column testing, two analytical approaches were suggested for computing the axial capacity of tested columns. Moreover, finite element (FE) analysis was performed for evaluating the axial load versus displacement response of tested columns. As an outcome of the study, the best strengthening scheme was proposed to be used by practicing engineers for axial upgrading of wall-like columns.
    Language English
    Publishing date 2023-04-14
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2527146-5
    ISSN 2073-4360 ; 2073-4360
    ISSN (online) 2073-4360
    ISSN 2073-4360
    DOI 10.3390/polym15081886
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article: ANN models for prediction of residual strength of HSC after exposure to elevated temperature

    Abbas, Husain / Almusallam, Tarek H / Al-Salloum, Yousef A / Elsanadedy, Hussein M

    Fire safety journal. 2019 June, v. 106

    2019  

    Abstract: Although high strength concrete (HSC) is becoming popular in building construction around the globe, its performance under high temperature (or fire) exposure is not precisely known. The existing fire-design provisions were developed mostly from the ... ...

    Abstract Although high strength concrete (HSC) is becoming popular in building construction around the globe, its performance under high temperature (or fire) exposure is not precisely known. The existing fire-design provisions were developed mostly from the results of fire tests on normal strength concrete (NSC) and thus their applicability to HSC needs to be evaluated because sufficient HSC data is now available. This paper is aimed at developing artificial neural network (ANN) based predictive relationships between the statistically significant parameters and the residual compressive strength of concrete for its application in structural fire design of HSC. The proposed models are based on a large set of experimental data that was collected through an extensive survey of the available tests on HSC after high-temperature exposure. The data was carefully examined and analyzed to identify the statistically significant/sensitive variables and to establish the influence of these variables on the residual strength of HSC. The database was used to check the validity/applicability of the existing design models of codes, standards, guidelines and several researchers. New ANN based residual strength design models for HSC were also proposed.
    Keywords building construction ; compression strength ; concrete ; databases ; fire testing ; guidelines ; neural networks ; prediction ; surveys ; temperature
    Language English
    Dates of publication 2019-06
    Size p. 13-28.
    Publishing place Elsevier Ltd
    Document type Article
    ZDB-ID 1483569-1
    ISSN 0379-7112
    ISSN 0379-7112
    DOI 10.1016/j.firesaf.2019.03.011
    Database NAL-Catalogue (AGRICOLA)

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