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7 pages, 187 KiB

Open AccessEditorial

Advances in Steel and Composite Steel—Concrete Bridges and Buildings

by Marco Bonopera

Infrastructures 2024, 9(10), 169; https://doi.org/10.3390/infrastructures9100169 - 25 Sep 2024

Viewed by 580

Abstract

Construction steel has widely been used worldwide for developing infrastructure, e [...] Full article

(This article belongs to the Special Issue Advances in Steel and Composite Steel–Concrete Bridges and Buildings)

Research

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17 pages, 8713 KiB

Open AccessArticle

Flexural Behavior of Concrete-Filled Steel Tube Beams Composite with Concrete Slab Deck

by Salam Maytham AlObaidi, Mohammed Abbas Mousa, Aqil M. Almusawi, Muhaned A. Shallal and Saif Alzabeebee

Infrastructures 2024, 9(10), 187; https://doi.org/10.3390/infrastructures9100187 - 17 Oct 2024

Viewed by 285

Abstract

Concrete-filled steel tube (CFST) beams have shown their flexural effectiveness in terms of stiffness, strength, and ductility. On the other hand, composite bridge girders demand durable and ductile girders to serve as tension members, while the concrete deck slab resists the compression stresses. [...] Read more.

Concrete-filled steel tube (CFST) beams have shown their flexural effectiveness in terms of stiffness, strength, and ductility. On the other hand, composite bridge girders demand durable and ductile girders to serve as tension members, while the concrete deck slab resists the compression stresses. In this study, six composite CFST beams with concrete slab decks with a span of 170 cm were investigated under a four-point bending test. The main variables of the study were the compressive strength of the concrete deck, the size of CFST beams, and the composite mechanism between the CFST girder and the concrete deck. The results showed that the flexural strength and ductility of the composite system increased by 20% with increasing concrete compressive strength. The study revealed that the higher-strength concrete slab deck enabled the CFST beam to exhibit improved flexural behavior with reduced deflections and enhanced resistance to cracking. The findings also highlighted the importance of considering the interactions between the steel tube and concrete slab deck in determining the flexural behavior of the composite system revealed by strain distribution along the composite beam profile as determined using the digital image correlation DIC technique, where a 40% increase in the flexural strength was obtained when a channel section was added to the joint of the composite section. Full article

(This article belongs to the Special Issue Advances in Steel and Composite Steel–Concrete Bridges and Buildings)

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19 pages, 4067 KiB

Open AccessArticle

Numerical Investigation of the Axial Load Capacity of Cold-Formed Steel Channel Sections: Effects of Eccentricity, Section Thickness, and Column Length

by Diyari B. Hussein and Ardalan B. Hussein

Infrastructures 2024, 9(9), 142; https://doi.org/10.3390/infrastructures9090142 - 26 Aug 2024

Viewed by 611

Abstract

Cold-formed steel channel (CFSC) sections have gained widespread adoption in building construction due to their advantageous properties, including superior energy efficiency, expedited construction timelines, environmental sustainability, material efficiency, and ease of transportation. This study presents a numerical investigation into the axial compressive behavior [...] Read more.

Cold-formed steel channel (CFSC) sections have gained widespread adoption in building construction due to their advantageous properties, including superior energy efficiency, expedited construction timelines, environmental sustainability, material efficiency, and ease of transportation. This study presents a numerical investigation into the axial compressive behavior of CFSC section columns. A rigorously developed finite element model for CFSC sections was validated against existing experimental data from the literature. Upon validation, the model was employed for an extensive parametric analysis encompassing a dataset of 208 CFSC members. Furthermore, the efficacy of the design methodologies outlined in the AISI Specification and AS/NZS Standard were evaluated by comparing the axial load capacities obtained from the numerically generated data with the results of four previously conducted experimental tests. The findings reveal that the codified design equations, based on nominal compressive resistances determined using the current direct strength method, exhibit a conservative bias. On average, these equations underestimate the actual load capacities of CFSC section columns by approximately 11.5%. Additionally, this investigation explores the influence of eccentricity, cross-sectional dimensions, and the point-of-load application on the axial load capacity of CFSC columns. The results demonstrate that a decrease in section thickness, an increase in column length, and a higher degree of eccentricity significantly reduce the axial capacity of CFSC columns. Full article

(This article belongs to the Special Issue Advances in Steel and Composite Steel–Concrete Bridges and Buildings)

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22 pages, 3664 KiB

Open AccessArticle

Buckling Instability of Monopiles in Liquefied Soil via Structural Reliability Assessment Framework

by Brian Bachinilla, Milind Siddhpura, Ana Evangelista, Ahmed WA Hammad and Assed N. Haddad

Infrastructures 2024, 9(8), 123; https://doi.org/10.3390/infrastructures9080123 - 26 Jul 2024

Viewed by 976

Abstract

During devastating earthquakes, soil liquefaction has disastrous outcomes on bridge foundations, as mentioned in books and published research. To avoid foundation failure when the surrounding soil is fully liquefied, a bridge’s pile foundation design could be such that the bridge pier is directly [...] Read more.

During devastating earthquakes, soil liquefaction has disastrous outcomes on bridge foundations, as mentioned in books and published research. To avoid foundation failure when the surrounding soil is fully liquefied, a bridge’s pile foundation design could be such that the bridge pier is directly resting on the top of a large-diameter monopile instead of the traditional multiple small-diameter piles. This paper discusses the gap of insufficient studies on large-diameter monopiles to support railway bridges subjected to buckling instability and the lack of simplified tools to quickly assess structural reliability. A framework could quickly assess the structural reliability by formulating a simplified reliability analysis. This study focused on pure buckling with shear deformation and reliability assessment to calculate a monopile’s failure probability in fully liquefied soils. In reliability assessment, with the critical pile length (L_crit) and the unsupported pile length (L_uns), the limit state function g(x) = [L_crit − L_uns] thus forms the basis for assessing the safety and reliability of a structure, indicating the state of success or failure. The L_crit formulation is accomplished with a differential equation. Here, L_uns assumes various depths of liquefied soil. The reliability index’s (β) formulation is achieved through the Hasofer–Lind concept and then double-checked through a normal or Gaussian distribution. A case study was conducted using a high-speed railway bridge model from a published research to demonstrate the application of the proposed methodology. To validate the minimum pile diameter for buckling instability when a fully liquefied soil’s thickness reaches the condition that L_crit = L_uns, this study applies the published research of Bhattacharya and Tokimatsu. The validation results show good agreement for 0.85–0.90 m monopile diameters. With a monopile diameter smaller than 0.85 m, the L_crit = L_uns limit was at lesser depths, while with a monopile diameter larger than 0.90 m, the L_crit = L_uns limit was at deeper depths. A load increase notably affected the large-diameter monopiles because the L_crit movement required a longer range. In fully liquefied soil, buckling will likely happen in piles with a diameter between 0.50 m and 1.60 m because the calculated probability of failure (Pf) value is nearly one. Conversely, buckling instability will likely not happen in monopiles with a diameter of 1.80–2.20 m because the Pf value is zero. Hence, the outcome of this case study suggests that the reliable monopile minimum diameter is 1.80 m for supporting a high-speed railway bridge. Lastly, this paper analyzed the shear deformation effect on large-diameter monopiles, the result of which was 0.30% of L_crit. Shear deformation makes minimal contributions to large-diameter monopile buckling. Full article

(This article belongs to the Special Issue Advances in Steel and Composite Steel–Concrete Bridges and Buildings)

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Figure 1
Bridge pier on a large-diameter monopile [<a href="#B1-infrastructures-09-00123" class="html-bibr">1</a>]. Full article ">Figure 2
Mathematical formulation framework of the current study. Full article ">Figure 3
Critical pile length and unsupported pile length hypothesis. Full article ">Figure 4
Shearing deformation on a column element [<a href="#B42-infrastructures-09-00123" class="html-bibr">42</a>]. Full article ">Figure 5
Hasofer-Lind Reliability Index for a linear state function [<a href="#B38-infrastructures-09-00123" class="html-bibr">38</a>]. Full article ">Figure 6
Validation of the current study using Bhattacharya and Tokimatsu’s study [<a href="#B40-infrastructures-09-00123" class="html-bibr">40</a>]. Full article ">Figure 7
Critical pile length comparison of the current study. Full article ">Figure 8
Probability of failure of the current study. Full article ">Figure 9
Shear deformation effect of the current study. Full article ">

26 pages, 23326 KiB

Open AccessArticle

Fatigue Consideration for Tension Flange over Intermediate Support in Skewed Continuous Steel I-Girder Bridges

by Dariya Tabiatnejad, Seyed Saman Khedmatgozar Dolati, Armin Mehrabi and Todd A. Helwig

Infrastructures 2024, 9(7), 99; https://doi.org/10.3390/infrastructures9070099 - 26 Jun 2024

Viewed by 1135

Abstract

Skewed supports complicate load paths in continuous steel I-girder bridges, causing secondary stresses and differential deformations. For a continuous bridge where tensile stresses are developed in the top flange of the steel girders over the intermediate supports, these effects may exacerbate potential fatigue [...] Read more.

Skewed supports complicate load paths in continuous steel I-girder bridges, causing secondary stresses and differential deformations. For a continuous bridge where tensile stresses are developed in the top flange of the steel girders over the intermediate supports, these effects may exacerbate potential fatigue issues for the top flanges. There is a gap in knowledge regarding the level of stress one can expect at these locations, and the stress level can render the problem either serious or trivial. This paper has been successful in providing this information, which was not available before. The study examines the fatigue performance of the top flange in girders over skewed supports. Results are presented from a detailed investigation consisting of 3D finite element modeling to evaluate 26 skewed bridges in the State of Florida that represent the wide range of geometries found in practice. The analysis focused on stress ranges in the top flanges and axial demands on end cross-frame members under fatigue truck loading. A preliminary analysis helped to select the appropriate element type and support conditions. The maximum factored stress range of 3.63 ksi obtained for the selected group of bridges remains below the 10 ksi fatigue threshold for an AASHTO Category C connection, alleviating the concerns about the fatigue performance of the continuous girder top flange over the intermediate pier. Hence, fatigue is unlikely to be a concern in the flanges at this location. Statistics on computed stress ranges and cross-frame forces that provide an understanding of the expected values and guidance for detailing practices are also presented. A limited comparative refined FE analysis on two different types of end cross-frame to girder connections also provided useful insight into the fatigue sensitivities of the skew connections. Half-Round Bearing Stiffener (HRBS) connections performed better than the customary bent plate connections. The HRBS connection reduces girder flange stress concentration range by at least 18% compared to the bent plate connection. The maximum stress concentration range in bent plate components is significantly higher than in the HRBS connection components. The work documented in this paper is important for understanding the fatigue performance of the cross-frames and girders in support regions in the upcoming 10th edition of the AASHTO Bridge Design Specifications that may include plate stiffeners oriented either normally or skewed to the girder web, or Half-Round Bearing Stiffeners. Full article

(This article belongs to the Special Issue Advances in Steel and Composite Steel–Concrete Bridges and Buildings)

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22 pages, 7410 KiB

Open AccessArticle

Bond Stress Behavior of a Steel Reinforcing Bar Embedded in Geopolymer Concrete Incorporating Natural and Recycled Aggregates

by Qasim Shaukat Khan, Haroon Akbar, Asad Ullah Qazi, Syed Minhaj Saleem Kazmi and Muhammad Junaid Munir

Infrastructures 2024, 9(6), 93; https://doi.org/10.3390/infrastructures9060093 - 31 May 2024

Cited by 2 | Viewed by 800

Abstract

The rise in greenhouse gases, particularly carbon dioxide (CO₂) emissions, in the atmosphere is one of the major causes of global warming and climate change. The production of ordinary Portland cement (OPC) emits harmful CO₂ gases, which contribute to sporadic [...] Read more.

The rise in greenhouse gases, particularly carbon dioxide (CO₂) emissions, in the atmosphere is one of the major causes of global warming and climate change. The production of ordinary Portland cement (OPC) emits harmful CO₂ gases, which contribute to sporadic heatwaves, rapid melting of glaciers, flash flooding, and food shortages. To address global warming and climate change challenges, this research study explores the use of a cement-less recycled aggregate concrete, a sustainable approach for future constructions. This study uses fly ash, an industrial waste of coal power plants, as a 100% substitute for OPC. Moreover, this research study also uses recycled coarse aggregates (RCAs) as a partial to complete replacement for natural coarse aggregates (NCAs) to preserve natural resources for future generations. In this research investigation, a total of 60 pull-out specimens were prepared to investigate the influence of steel bar diameter (9.5 mm, 12.7 mm, and 19.1 mm), bar embedment length,

d_{b}

(4

d_{b}

and 6

d_{b}

), and percentage replacements of NCA with RCA (25%, 50%, 75%, and 100%) on the bond stress behavior of cement-less RA concrete. The test results exhibited that the bond stress of cement-less RCA concrete decreased by 6% with increasing steel bar diameter. Moreover, the bond stress decreased by 5.5% with increasing bar embedment length. Furthermore, the bond stress decreased by 7.6%, 7%, 8.8%, and 20.4%, respectively, with increasing percentage replacements (25%, 50%, 75%, and 100%) of NCA with RCA. An empirical model was developed correlating the bond strength to the mean compressive strength of cement-less RCA concrete, which matched well with the experimental test results and predictions of the CEB-FIP model for OPC. The CRAC mixes exhibited higher costs but significantly lower embodied CO₂ emissions than OPC concrete. Full article

(This article belongs to the Special Issue Advances in Steel and Composite Steel–Concrete Bridges and Buildings)

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The materials used in GPC are (a) fly ash, (b) sand, (c) NCA, and (d) RCA. Full article ">Figure 2
Concrete crusher machine. Full article ">Figure 3
Stages in the preparation of alkaline activator solution used in GPC. Full article ">Figure 4
Detail of pull-out test specimen. Full article ">Figure 5
Steel bars enveloped with PVC tubes. Full article ">Figure 6
Cylindrical molds placed on a mechanical vibrating table before concrete pouring. Full article ">Figure 7
Demolded samples stored at room temperature. Full article ">Figure 8
Pull-out test setup. Full article ">Figure 9
Yielding/bond failure in tested pull-out specimens. Full article ">Figure 10
Splitting failure in pull-out test specimens. Full article ">Figure 11
Influence of embedment lengths on bond stress of CRAC mixes. Full article ">Figure 12
Influence of varying diameters of embedded steel bar in CRAC mixes. Full article ">Figure 13
Influence of varying percentage replacements of NCA with RCA in the CRAC mix. Full article ">Figure 14
Stress–slip curves of tested pull-out specimens. Full article ">Figure 15
Analytical predictions of bond stress with varying compressive strength using existing models and the proposed model [<a href="#B25-infrastructures-09-00093" class="html-bibr">25</a>,<a href="#B48-infrastructures-09-00093" class="html-bibr">48</a>,<a href="#B49-infrastructures-09-00093" class="html-bibr">49</a>,<a href="#B51-infrastructures-09-00093" class="html-bibr">51</a>,<a href="#B52-infrastructures-09-00093" class="html-bibr">52</a>]. Full article ">

29 pages, 10022 KiB

Open AccessArticle

The Influence of Soil Deformability on the Seismic Response of 3D Mixed R/C–Steel Buildings

by Paraskevi K. Askouni

Infrastructures 2024, 9(5), 80; https://doi.org/10.3390/infrastructures9050080 - 4 May 2024

Viewed by 1172

Abstract

Following effective seismic codes, common buildings are considered to be made of the same material throughout the story distribution and based on an ideal rigid soil. However, in daily construction practice, there are often cases of buildings formed by a bottom part constructed [...] Read more.

Following effective seismic codes, common buildings are considered to be made of the same material throughout the story distribution and based on an ideal rigid soil. However, in daily construction practice, there are often cases of buildings formed by a bottom part constructed with reinforced concrete (r/c) and a higher steel part, despite this construction type not being recognized by code assumptions. In addition, soil deformability, commonly referred to as the Soil–Structure Interaction (SSI), is widely found to affect the earthquake response of typical residence structures, apart from special structures, though it is not included in the normative design procedure. This work studies the seismic response of in-height mixed 3D models, considering the effect of sustaining deformable ground compared to the common rigid soil hypothesis, which has not been clarified so far in the literature. Two types of soft soil, as well as the rigid soil assumption, acting as a reference point, are considered, while two limit interconnections between the steel part on the concrete part are included in the group analysis. The possible influence of the seismic orientation angle is explored in the analysis set. Selected numerical results of the dynamic nonlinear analyses under strong near-fault ground excitations were plotted through dimensionless parameters to facilitate an objective comparative discussion. The effect of SSI on the nonlinear performance of three-dimensional mixed models is identified, which serves as the primary contribution of this work, making it unique among the numerous research works available globally and pointing to findings that are useful for the enhancement of the seismic rules regarding the design and analysis of code-neglected mixed buildings. Full article

(This article belongs to the Special Issue Advances in Steel and Composite Steel–Concrete Bridges and Buildings)

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33 pages, 8700 KiB

Open AccessFeature PaperArticle

Enhancing Flexural Strength of RC Beams with Different Steel–Glass Fiber-Reinforced Polymer Composite Laminate Configurations: Experimental and Analytical Approach

by Arash K. Pour, Mehrdad Karami and Moses Karakouzian

Infrastructures 2024, 9(4), 73; https://doi.org/10.3390/infrastructures9040073 - 12 Apr 2024

Cited by 1 | Viewed by 1620 | Correction

Abstract

This study intended to measure the efficiency of different strengthening techniques to advance the flexural characteristics of reinforced concrete (RC) beams using glass fiber-reinforced polymer (GFRP) laminates, including externally bonded reinforcement (EBR), externally bonded reinforcement on grooves (EBROG), externally bonded reinforcement in grooves [...] Read more.

This study intended to measure the efficiency of different strengthening techniques to advance the flexural characteristics of reinforced concrete (RC) beams using glass fiber-reinforced polymer (GFRP) laminates, including externally bonded reinforcement (EBR), externally bonded reinforcement on grooves (EBROG), externally bonded reinforcement in grooves (EBRIG), and the near-surface mounted (NSM) system. A new NSM technique was also established using an anchorage rebar. Then, the effect of the NSM method with and without externally strengthening GFRP laminates was studied. Twelve RC beams (150 × 200 × 1500 mm) were manufactured and examined under a bending system. One specimen was designated as the control with no GFRP laminate. To perform the NSM method, both steel and GFRP rebars were used. In the experiments, capability, as well as the deformation and ductileness of specimens, were evaluated, and a comparison was made between the experimental consequences and existing standards. Finally, a new regression was generated to predict the final resistance of RC beams bound with various retrofitting techniques. The findings exhibited that the NSM technique, besides preserving the strengthening materials, could enhance the load-bearing capacity and ductileness of RC beams up to 42.3% more than the EBR, EBROG, and EBRIG performances. Full article

(This article belongs to the Special Issue Advances in Steel and Composite Steel–Concrete Bridges and Buildings)

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22 pages, 6290 KiB

Open AccessArticle

Joint Behavior of Full-Scale Precast Concrete Pipe Infrastructure: Experimental and Numerical Analysis

by Abdul Basit, Safeer Abbas, Muhammad Mubashir Ajmal, Ubaid Ahmad Mughal, Syed Minhaj Saleem Kazmi and Muhammad Junaid Munir

Infrastructures 2024, 9(4), 69; https://doi.org/10.3390/infrastructures9040069 - 3 Apr 2024

Cited by 2 | Viewed by 1647

Abstract

This study undertakes a comprehensive experimental and numerical analysis of the structural integrity of buried RC sewerage pipes, focusing on the performance of two distinct jointing materials: cement mortar and non-shrinkage grout. Through joint shear tests on full-scale sewer pipes under single point [...] Read more.

This study undertakes a comprehensive experimental and numerical analysis of the structural integrity of buried RC sewerage pipes, focusing on the performance of two distinct jointing materials: cement mortar and non-shrinkage grout. Through joint shear tests on full-scale sewer pipes under single point loading conditions, notable effects on the crown and invert of the joint were observed, highlighting the critical vulnerability of these structures to internal and external pressures. Two materials—cement–sand mortar and non-shrinkage grout—were used in RC pipe joints to experimentally evaluate the joint strength of the sewerage pipes. Among the materials tested, cement–sand mortar emerged as the superior choice, demonstrating the ability to sustain higher loads up to 25.60 kN, proving its cost-effectiveness and versatility for use in various locations within RC pipe joints. Conversely, non-shrinkage grout exhibited the lowest ultimate failure load, i.e., 21.50 kN, emphasizing the importance of material selection in enhancing the resilience and durability of urban infrastructure. A 3D finite element (FE) analysis was also employed to assess the effect of various factors on stress distribution and joint deformation. The findings revealed a 10% divergence between the experimental and numerical data regarding the ultimate load capacity of pipe joints, with experimental tests indicating a 25.60 kN ultimate load and numerical simulations showing a 23.27 kN ultimate load. Despite this discrepancy, the close concordance between the two sets of data underscores the utility of numerical simulations in predicting the behavior of pipe joints accurately. This study provides valuable insights into the selection and application of jointing materials in sewerage systems, aiming to improve the structural integrity and longevity of such critical infrastructure. Full article

(This article belongs to the Special Issue Advances in Steel and Composite Steel–Concrete Bridges and Buildings)

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15 pages, 4028 KiB

Open AccessArticle

Corrosion of Steel Rebars in Construction Materials with Reinforced Pervious Concrete

by Rosendo Lerma Villa, José Luis Reyes Araiza, José de Jesús Pérez Bueno, Alejandro Manzano-Ramírez and Maria Luisa Mendoza López

Infrastructures 2024, 9(4), 68; https://doi.org/10.3390/infrastructures9040068 - 1 Apr 2024

Viewed by 1751

Abstract

Pervious concrete has great potential for use in many practical applications as a part of urban facilities that can add value through water harvesting and mitigating severe damage from floods. The construction and agricultural industries can take direct advantage of pervious concrete’s characteristics [...] Read more.

Pervious concrete has great potential for use in many practical applications as a part of urban facilities that can add value through water harvesting and mitigating severe damage from floods. The construction and agricultural industries can take direct advantage of pervious concrete’s characteristics when water is a key factor included in projects as part of the useful life of a facility. Pervious concrete also has applications in vertical constructions, fountains, and pedestrian crossings. This work evidences that pervious concrete’s corrosion current increases with increasing aggregate size. Also, corrosion is a factor to consider only when steel pieces are immersed, aggravated by the presence of chlorine, but it drains water and does not retain moisture. Steel-reinforced pervious concrete was studied, and the grain size of the inert material and the corrosion process parameters were investigated. The electrochemical frequency modulation technique is proposed as a suitable test for a fast, reproducible assessment which, without damaging reinforced cement structures, particularly pervious concrete, indicates a trend of increasing corrosion current density as the size of the aggregate increases or density diminishes. Full article

(This article belongs to the Special Issue Advances in Steel and Composite Steel–Concrete Bridges and Buildings)

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16 pages, 5200 KiB

Open AccessArticle

Experimental and Numerical Evaluation of Equivalent Stress Intensity Factor Models under Mixed-Mode (I+II) Loading

by Estefanía Gómez-Gamboa, Jorge Guillermo Díaz-Rodríguez, Jairo Andrés Mantilla-Villalobos, Oscar Rodolfo Bohórquez-Becerra and Manuel del Jesús Martínez

Infrastructures 2024, 9(3), 45; https://doi.org/10.3390/infrastructures9030045 - 1 Mar 2024

Cited by 4 | Viewed by 2346

Abstract

This study determines the equivalent stress intensity factor (SIF) model that best fits the experimental behavior of low-carbon steel under mixed modes (

I

and

I I

). The study assessed Tanaka, Richard, and Pook’s equivalent SIF models. The theoretical values used for [...] Read more.

This study determines the equivalent stress intensity factor (SIF) model that best fits the experimental behavior of low-carbon steel under mixed modes (

I

and

I I

). The study assessed Tanaka, Richard, and Pook’s equivalent SIF models. The theoretical values used for comparison correspond to the experimental results in a modified C(T) geometry by machining a hole ahead of the crack tip subjected to fatigue loads with a load ratio of R = 0.1. The comparison involved the SIF for six experimental points and the values computed through the numerical simulation. The Paris, Klesnil, and Modified Forman–Newman crack growth models were used with each equivalent SIF to analyze the prediction in the estimated number of cycles. The Klesnil model showed the closest prediction since the error between the calculated and experimentally recorded number of cycles is the lowest. However, the material behavior reflects a reduced crack propagation rate attributed to plasticity in the crack tip. The results suggest that Asaro equivalent SIF conservatively estimates the element lifespan with increasing errors from 2.3% at the start of growth to 27% at the end of the calculation. This study sheds light on the accuracy and limitations of different equivalent SIF models, providing valuable insights for structural integrity assessments in engineering applications. Full article

(This article belongs to the Special Issue Advances in Steel and Composite Steel–Concrete Bridges and Buildings)

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13 pages, 7907 KiB

Open AccessArticle

Fatigue Characteristics of Steel–Concrete Composite Beams

by Ayman El-Zohairy, Hani Salim, Hesham Shaaban and Mahmoud T. Nawar

Infrastructures 2024, 9(2), 29; https://doi.org/10.3390/infrastructures9020029 - 4 Feb 2024

Viewed by 1920

Abstract

Fatigue in steel–concrete composite beams can result from cyclic loading, causing stress fluctuations that may lead to cumulative damage and eventual failure over an extended period. In this paper, the experimental findings from fatigue loading tests on composite beams with various arrangements are [...] Read more.

Fatigue in steel–concrete composite beams can result from cyclic loading, causing stress fluctuations that may lead to cumulative damage and eventual failure over an extended period. In this paper, the experimental findings from fatigue loading tests on composite beams with various arrangements are presented. Fatigue tests were performed up to 1,000,000 cycles using four-point loading, encompassing various ranges of shear stress at a consistent amplitude. Additionally, the effects of external post-tensioning and the strength of the shear connection were investigated. Static tests were run until failure to assess the enduring strength of the specimens subjected to fatigue. The cyclic mid-span deflections, slippages, and strains were measured during the testing. Based on the experimental findings, it was found that the damage region that the shear studs caused in the concrete slab, which resulted in a reduction in stiffness within the shear connection, grew as the loading cycles increased, leading to an increase in residual deflections and plastic slippages. Controlling the longitudinal fatigue cracks in the concrete slab was largely dependent on the strength of the shear connection between the steel beams and concrete slabs. Moreover, the applied fatigue loading range affected the propagation and distribution of fatigue cracks in the concrete slab. The strains in different parts of the composite specimens were significantly reduced by applying the external post-tensioning. With no signs of distress at the anchors, the tendons displayed excellent fatigue performance. Full article

(This article belongs to the Special Issue Advances in Steel and Composite Steel–Concrete Bridges and Buildings)

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24 pages, 21460 KiB

Open AccessArticle

Strength and Deformation of Concrete-Encased Grouting-Filled Steel Tubes Columns Exposed to Monotonic Quasi-Static Loading Conditions

by Ahlam A. Abbood, Nazar Oukaili, Abbas A. Allawi and George Wardeh

Infrastructures 2024, 9(2), 26; https://doi.org/10.3390/infrastructures9020026 - 1 Feb 2024

Cited by 1 | Viewed by 1851

Abstract

This study aimed to evaluate the effectiveness of a novel concrete-encased column (CE) using small circular steel tubes filled with cementitious grouting material (GFST) as the primary reinforcement instead of traditional steel bars. The research involved three different types of reinforcement: conventional steel [...] Read more.

This study aimed to evaluate the effectiveness of a novel concrete-encased column (CE) using small circular steel tubes filled with cementitious grouting material (GFST) as the primary reinforcement instead of traditional steel bars. The research involved three different types of reinforcement: conventional steel bars, concrete-filled steel tubes with 30% of the reinforcement ratio of steel bars, and concrete-filled steel tubes with the same reinforcement ratio as steel bars. Twenty-four circular concrete columns were tested and categorized into six groups based on the type of reinforcement employed. Each group comprised four columns, with one subjected to concentric axial load, two subjected to eccentric axial load (with eccentricities of 25 mm and 50 mm, respectively), and one tested under lateral flexural loads. To validate the experimental results, finite element (FE) analysis was conducted using ABAQUS software version 6.14. The experimental findings for concentric load reveal that columns with the second type of reinforcement, concrete-filled steel tubes with 30% of the reinforcement ratio of steel bars exhibited a failure load 19% lower than those with steel bars, while columns with the third type of reinforcement, concrete-filled steel tubes with the same reinforcement ratio as steel bars achieved a failure load 17% greater than the traditional steel bars. The FE analysis demonstrates good agreement with the experimental outcomes in terms of ultimate strength, deformation, and failure modes. Full article

(This article belongs to the Special Issue Advances in Steel and Composite Steel–Concrete Bridges and Buildings)

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1 pages, 127 KiB

Open AccessCorrection

Correction: Pour et al. Enhancing Flexural Strength of RC Beams with Different Steel–Glass Fiber-Reinforced Polymer Composite Laminate Configurations: Experimental and Analytical Approach. Infrastructures 2024, 9, 73

by Arash K. Pour, Mehrdad Karami and Moses Karakouzian

Infrastructures 2024, 9(7), 111; https://doi.org/10.3390/infrastructures9070111 - 15 Jul 2024

Viewed by 489

Abstract

In the published publication [...] Full article

(This article belongs to the Special Issue Advances in Steel and Composite Steel–Concrete Bridges and Buildings)

14 pages, 5911 KiB

Open AccessTechnical Note

Practical Aspects of Correlation Analysis of Compressive Strength from Destructive and Non-Destructive Methods in Different Directions

by Baitollah Badarloo and Petr Lehner

Infrastructures 2023, 8(11), 155; https://doi.org/10.3390/infrastructures8110155 - 24 Oct 2023

Viewed by 2133

Abstract

The research presented here demonstrates the practical aspects of the numerical correlation of the results of the compressive strength test. The destructive test (DT) in a hydraulic press and the non-destructive test (NDT) using a Schmidt hammer in several process variations were evaluated. [...] Read more.

The research presented here demonstrates the practical aspects of the numerical correlation of the results of the compressive strength test. The destructive test (DT) in a hydraulic press and the non-destructive test (NDT) using a Schmidt hammer in several process variations were evaluated. The aim was to evaluate the real differences between the tool supplier’s curve and testing. Therefore, 150 concrete cube specimens with an edge length of 150 mm were produced using a mixture of three types of concrete classes: C30, C35, and C40. The test was carried out 7 and 28 days of age of the concrete. The Schmidt hammer test was carried out in horizontal (θ = 0) and vertical (θ = 90) directions and using a series of 10 measurements. Furthermore, the tests were performed in two sets: first, the sample was placed on the ground, and second, under a hydraulic jack with a load of 50% of the maximum bearing capacity of specific concrete. Then, regression analysis was performed on the data sets to establish linear mathematical relationships between compressive strength and number of bounces. The results showed that the correlation between the DT and NDT tests has a high value for each group, but the correlation equations are different and must be taken into account. Full article

(This article belongs to the Special Issue Advances in Steel and Composite Steel–Concrete Bridges and Buildings)

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