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22 pages, 10937 KiB

Open AccessArticle

Numerical Investigation on Strengthening of Steel Beams for Corrosion Damage or Web Openings Using Carbon Fiber Reinforced Polymer Sheets

by Prabin Kumar Silwal, Azadeh Parvin and Mohannad Alhusban

Buildings 2024, 14(4), 1069; https://doi.org/10.3390/buildings14041069 - 11 Apr 2024

Viewed by 313

Abstract

Fiber-reinforced polymers (FRPs) have been widely used to strengthen steel structures, which could suffer from corrosion or the introduction of web openings, for utilities such as ductwork, plumbing, electrical conduits, and HVAC systems. The present numerical study involves the application of unidirectional carbon [...] Read more.

Fiber-reinforced polymers (FRPs) have been widely used to strengthen steel structures, which could suffer from corrosion or the introduction of web openings, for utilities such as ductwork, plumbing, electrical conduits, and HVAC systems. The present numerical study involves the application of unidirectional carbon FRP (CFRP) sheets to steel I-beams, damaged due to corrosion or web openings, to regain their lost load-carrying capacity. Finite element analysis (FEA) was utilized to develop and validate three beam models against existing experimentally tested specimens. Subsequently, a parametric study was conducted investigating the effect of various corrosion levels and the number of circular web openings on the yield and ultimate load capacities of the beams. The optimum number of CFRP layers needed to strengthen corroded beams was determined and six CFRP strengthening scenarios were adopted to determine the best configurations to retrofit steel beams with openings (SBWOs). The results revealed that corrosion, introduced by thinning the bottom flange, reduced both yield and ultimate load capacities, with a nearly perfect linear reduction in ultimate load for each 2.5% thickness loss. The optimum number of CFRP layers depended on the level of corrosion damage. Furthermore, while maintaining a constant total opening area, beams with a greater number of smaller circular web openings demonstrated higher yield and ultimate load capacities than those with fewer larger openings. Out of the six adopted CFRP strengthening scenarios, three configurations that involved applying CFRP sheets to both flanges and the web effectively restored the strength of SBWOs, when adequate CFRP layers were used. Full article

(This article belongs to the Special Issue Advanced Composite Materials for Structure Strengthening and Resilience Improving)

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15 pages, 7260 KiB

Open AccessArticle

Tests and Seismic Response Analysis of Guided-Rail-Type Anti-Tensile Rubber Bearing

by Longfei Zhang, Xiang Lan, Kechuan Wu and Wenzheng Yu

Buildings 2024, 14(4), 992; https://doi.org/10.3390/buildings14040992 - 03 Apr 2024

Viewed by 315

Abstract

When subjected to seismic activity, tall isolated buildings with a high aspect ratio are susceptible to overturning as a result of the failure of rubber isolation bearings under tension. In order to address this issue, a guided-rail tension device (GR) has been developed [...] Read more.

When subjected to seismic activity, tall isolated buildings with a high aspect ratio are susceptible to overturning as a result of the failure of rubber isolation bearings under tension. In order to address this issue, a guided-rail tension device (GR) has been developed to enhance the tensile strength of rubber bearings. Furthermore, a novel guided-rail isolation rubber bearing (GR&RB) has been proposed as a potential solution. Quasi-static tests have been conducted to investigate the mechanical properties of the GR, as well as the GR&LNR600 and LNR600. Additionally, numerical finite element analysis has been employed to study the seismic response of the GR&RB under El Centro seismic action in a high-rise building with an aspect ratio of approximately 4. The experimental results suggest that the inclusion of GRs has a limited effect on the horizontal mechanical attributes of rubber isolation bearings. Nevertheless, it simultaneously enhances their tensile strength, demonstrating a significant augmentation of 4.23 times. Moreover, the mechanical behavior of the GR aligns with the Hook model. The numerical analysis suggests that the utilization of GR&RB can mitigate the tensile stress levels of rubber isolators. Furthermore, it is recommended to augment the elastic tensile stiffness of the GR while reducing the open value to enhance the tensile efficiency, with the potential to attain up to 75% efficiency in tensile performance. Full article

(This article belongs to the Special Issue Advanced Composite Materials for Structure Strengthening and Resilience Improving)

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23 pages, 15303 KiB

Open AccessArticle

Numerical Study on Mechanical Behaviors of New Type of Steel Shear-Connection Horizontal Joint in Prefabricated Shear Wall Structure

by Xiaohui Wu, Yanfeng Wang, Shaofeng Ji, Mengze Liu and Dayang Wang

Buildings 2023, 13(12), 3000; https://doi.org/10.3390/buildings13123000 - 30 Nov 2023

Viewed by 769

Abstract

The shear connection joint is an important component of the prefabricated shear wall structure system, which plays a dual role in ensuring reasonable force transmission and structural integrity. A new type of steel shear-connection horizontal joint was proposed in this study. In order [...] Read more.

The shear connection joint is an important component of the prefabricated shear wall structure system, which plays a dual role in ensuring reasonable force transmission and structural integrity. A new type of steel shear-connection horizontal joint was proposed in this study. In order to verify the effectiveness of the proposed new joint, the established numerical model and its constitutive relationship were first verified based on the existing experimental results. Then, the influence effect on the mechanical behaviors of this new type of joint was further investigated with 20 computational cases. The corresponding influencing laws were established, and optimal parameter ranges were suggested. Finally, a simplified constitutive model—namely, a bilinear constitutive model based on the M-θ relationship—of the new steel shear-connection joint is further advanced and deduced. The results show that the proposed new joint can provide stable shear capacity and superior energy dissipation capacity. The interlocking slot in the new steel shear-connection joint is suggested to be designed with a slot length of 20~30 mm, a slot number of two or three, and a slot thickness of 20~30 mm so as to guarantee superior mechanical behaviors. The advanced bilinear constitutive model can effectively capture the mechanical characteristics of the new joints, in which the maximum error is only 7.67% between theory and simulation. Full article

(This article belongs to the Special Issue Advanced Composite Materials for Structure Strengthening and Resilience Improving)

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18 pages, 7487 KiB

Open AccessArticle

Nonlinear Dynamic Stability of Cylindrical Reticulated Shells with Initial Damage

by Lei Li, Guangfeng Li, Nasim Uddin, Limin Tian, Zhibing Zhu, Chong Bai and Chen Shen

Buildings 2023, 13(11), 2852; https://doi.org/10.3390/buildings13112852 - 14 Nov 2023

Viewed by 609

Abstract

As large-span structures, reticulated shells are widely used in large-scale public building and act as emergency shelters in the event of sudden disasters. However, spatial reticulated shells are dynamic-sensitive structures; the effect of the initial structural damage on dynamic stability should be considered. [...] Read more.

As large-span structures, reticulated shells are widely used in large-scale public building and act as emergency shelters in the event of sudden disasters. However, spatial reticulated shells are dynamic-sensitive structures; the effect of the initial structural damage on dynamic stability should be considered. In this study, a new nonlinear dynamic model of cylindrical reticulated shells with initial damage is proposed to investigate the effect of initial damage accurately. Firstly, the damage constitutive relations of the building steels are built based on the irreversible thermodynamic theory; furthermore, its fundamental equations are obtained using simulated shell methods. Then, the nonlinear vibration differential equations with damage are obtained and studied with support. Meanwhile, the nonlinear natural vibration frequency with initial damage is derivatized. After that, a bifurcation problem with initial damage is studied by using Flouquet Index, and the dynamic stability state at the equilibrium point is analyzed in depth. It is found that the local dynamic stability of the system is determined via its initial condition, geometric parameters, and initial damage. Moreover, the initial damage dominates over other influence factors due to its strong randomness and uncertainty for the same structure. The damage accumulation results in the transition of the equilibrium point. In addition, the nonlinear natural vibration frequency decreases to zero with the accumulation of the damage reaching 0.618; the local stability of cylindrical reticulated shells fails and they even lose whole stability. This study provides a theoretical foundation for the future investigation of whole stability with initial damage. Full article

(This article belongs to the Special Issue Advanced Composite Materials for Structure Strengthening and Resilience Improving)

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12 pages, 2314 KiB

Open AccessArticle

Mechanical Property Research for CSIP Thin-Wall Box-Beams

by Lei Li, Nasim Uddin, Xianxian Zhao and Limin Tian

Buildings 2023, 13(7), 1822; https://doi.org/10.3390/buildings13071822 - 19 Jul 2023

Viewed by 609

Abstract

Composite structural insulated panels (CSIPs) are eco-friendly, high-performance materials, which not only good have mechanical properties, but also good waterproof, moisture-proof, fire-proof, and anti-corrosion characteristics, so they have been used to build envelope structures in recent years. However, how to improve stiffness of [...] Read more.

Composite structural insulated panels (CSIPs) are eco-friendly, high-performance materials, which not only good have mechanical properties, but also good waterproof, moisture-proof, fire-proof, and anti-corrosion characteristics, so they have been used to build envelope structures in recent years. However, how to improve stiffness of CSIPs remains unsolved. The poor stiffness is one of the biggest obstacles for the application of CSIPs in the load-bearing members of civil engineering. In this study, the layout of glass–polypropylene (PP) laminate layers is designed to enhance its stiffness, and this study applies CSIPs as load-bearing members of civil engineering for the first time. Thus, the bend model of CSIP thin-wall box-beams under uniform loading is built, based on Timochenko’s theory. The deflection curve equation is presented, considering shearing deformation. The expressions for the bending of normal strain flanges of the beam and the equation considering principal shearing strain at the beam’s web are obtained, respectively. Finally, mechanical properties of the thin-wall box-beam under uniformly distributed loads were performed by FE. FE results are entirely consistent with the theoretical results, thereby making the theoretical method applicable for the design of thin-wall box-beams, which are made of composite materials. Different from other beams, the shearing deformation is a critical factor that influences the deformation of thin-walled box-beams. Full article

(This article belongs to the Special Issue Advanced Composite Materials for Structure Strengthening and Resilience Improving)

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11 pages, 6553 KiB

Open AccessArticle

Research on Fatigue Performance of Shape-Memory Alloy Bars under Low Cyclic Loading

by Lei Li, Xianxian Zhao and Junwei Cheng

Buildings 2023, 13(6), 1553; https://doi.org/10.3390/buildings13061553 - 18 Jun 2023

Cited by 2 | Viewed by 923

Abstract

In recent years, shape memory alloys (SMAs) have been applied in the vibration control of engineering structures due to their special properties such as super elasticity and high damping, and the study of the performance of SMA wires has been relatively comprehensive, while [...] Read more.

In recent years, shape memory alloys (SMAs) have been applied in the vibration control of engineering structures due to their special properties such as super elasticity and high damping, and the study of the performance of SMA wires has been relatively comprehensive, while research on the fatigue performance of SMA bars via cyclic tensile tests has been pretty rare, and low-cycle fatigue test has not been reported. However, the damage to building structures caused by earthquakes is of high-strain, low-cycle fatigue; therefore, in order for SMA bars to be used in seismic design, low-cycle fatigue tests were conducted on SMA bars with a diameter of 14 mm in this paper. Firstly, specimens were heat treated at a constant temperature of 350 °C for 30 min; other specimens were heat treated at a constant temperature of 400 °C for 15 min, while the rests were heat treated under a constant temperature of 400 °C for 30 min. Secondly, the energy dissipation capacity and residual strain of the SMA bar specimens were determined using the low-cycle fatigue test, in which the strain amplitudes were 2.5%, 3.5% and 3.75%. Additionally, the stress–strain relationship for SMA bars under cyclic loading was given. Finally, low-cycle fatigue properties of SMA bars were numerically simulated in the comparison analysis with the experimental results to verify their feasibility. Thus, it is proved that SMA bars can be recommend for seismic design building structures. Full article

(This article belongs to the Special Issue Advanced Composite Materials for Structure Strengthening and Resilience Improving)

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18 pages, 3109 KiB

Open AccessArticle

Experimental and Theoretical Investigation of Viscoelastic Damper by Applying Fractional Derivative Method and Internal Variable Theory

by Yeshou Xu, Qi He, Ying-Qing Guo, Xing-Huai Huang, Yao-Rong Dong, Zhong-Wei Hu and Jinkoo Kim

Buildings 2023, 13(1), 239; https://doi.org/10.3390/buildings13010239 - 14 Jan 2023

Cited by 5 | Viewed by 1677

Abstract

Viscoelastic dampers are conventional passive vibration control devices with excellent energy dissipation performance. The fractional derivative has a simple form and high accuracy in the modelling of viscoelastic materials/dampers. The internal variables reflect the internal state evolution of materials, and are often used [...] Read more.

Viscoelastic dampers are conventional passive vibration control devices with excellent energy dissipation performance. The fractional derivative has a simple form and high accuracy in the modelling of viscoelastic materials/dampers. The internal variables reflect the internal state evolution of materials, and are often used to analyze the deformation and thermal process of materials. In the present work, the mechanical properties of a plate-shear-type viscoelastic damper at room temperature are tested under sinusoidal displacement excitations. The impacts of frequency and displacement amplitude on the dynamic properties of the viscoelastic damper in a wide frequency domain (0.1–25 Hz) are investigated. The higher-order fractional derivative model and the temperature–frequency equivalent principle are employed to characterize the frequency and temperature influence, and the internal variable theory considering the internal/microscale structure evolutions is introduced to capture the displacement affection. The higher-order fractional derivative model modified with the internal variable theory and temperature–frequency equivalent principle (ITHF) is accurate enough in describing the dynamic behaviors of viscoelastic dampers with varying frequencies and displacement amplitudes. Full article

(This article belongs to the Special Issue Advanced Composite Materials for Structure Strengthening and Resilience Improving)

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19 pages, 6557 KiB

Open AccessArticle

In Situ Concrete Bridge Strengthening Using Ductile Activated NSMR CFRP System

by Jacob Wittrup Schmidt, John Dalsgaard Sørensen and Christian Overgaard Christensen

Buildings 2022, 12(12), 2244; https://doi.org/10.3390/buildings12122244 - 16 Dec 2022

Cited by 1 | Viewed by 1100

Abstract

Novel and complex structural solutions are often challenging to introduce in the building industry since they may provide unconventional and less verified behavior combined with several novel and unique failure modes. A desired safety level may be difficult to verify due to the [...] Read more.

Novel and complex structural solutions are often challenging to introduce in the building industry since they may provide unconventional and less verified behavior combined with several novel and unique failure modes. A desired safety level may be difficult to verify due to the lack of knowledge related to failure modes and their variation. This study introduces a method that may provide a first step toward addressing such challenges. Five laboratory tests were done on a novel ductile response-controlled anchor system used for prestressed CFRP NSMR strengthening. These results were used as a basis for further implementation in a pilot project where an in situ cast concrete bridge was strengthened with the developed system. A particular focus was dedicated to the capability of the designed system response to provide a consistent load/deformation curve, yielding threshold, and yielding regime. The novel system enabled response tailoring to the specific pilot project. Installation and prestressing procedure worked as desired, where losses in the fully prestressed system, after three weeks, were approximately 0.2 to 1.6 kN (0.2–1.3 mm). In situ proof loading of all strengthening systems (20 anchor systems) was done to eliminate any possible failure modes below the proof-loading level. It was performed with no signs of distress. Full article

(This article belongs to the Special Issue Advanced Composite Materials for Structure Strengthening and Resilience Improving)

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21 pages, 3741 KiB

Open AccessArticle

Assessment of Durability Indicators for Service Life Prediction of Portland Limestone Cementitious Systems Produced with Permeability-Reducing Admixtures

by Athanasios Malakopoulos and Athanasios Salifoglou

Buildings 2022, 12(10), 1712; https://doi.org/10.3390/buildings12101712 - 17 Oct 2022

Cited by 2 | Viewed by 1314

Abstract

Supplementary cementing materials (SCMs) and the challenges associated with admixture compatibility and durability performance are continuous challenges for the construction industry. Utilizing SCMs has apparent benefits in reducing the carbon footprint and improving the durability performance of concrete structures. This work investigates the [...] Read more.

Supplementary cementing materials (SCMs) and the challenges associated with admixture compatibility and durability performance are continuous challenges for the construction industry. Utilizing SCMs has apparent benefits in reducing the carbon footprint and improving the durability performance of concrete structures. This work investigates the performance of mortars composed of Portland limestone cement, calcium carbonate, butyl stearate, and oleic acid. The effort focuses on transport properties using electrical resistivity, chloride migration, porosity, and water permeability measurements. Then, various methods based on the last parameters are compared to assess the changes in the effective chloride diffusion coefficient and the intrinsic liquid water permeability. Measurements for drying shrinkage, thermal expansion, and compressive strength are conducted to verify durability and mechanical performance. The effect of the admixture addition on the service life of a structure fully submerged in marine exposure conditions is then evaluated using Fick’s second law of diffusion and the approach described by FIB model code 34. The results indicate that incorporating calcium carbonate, butyl stearate, and oleic acid in mortar mixtures provides enhanced durability compared to plain Portland limestone cement mortars. Full article

(This article belongs to the Special Issue Advanced Composite Materials for Structure Strengthening and Resilience Improving)

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23 pages, 9032 KiB

Open AccessArticle

Study on Mechanical Properties and Durability of Alkali-Activated Silicomanganese Slag Concrete (AASSC)

by Baifu Luo, Dong Wang and Elchalakani Mohamed

Buildings 2022, 12(10), 1621; https://doi.org/10.3390/buildings12101621 - 06 Oct 2022

Cited by 2 | Viewed by 1638

Abstract

Alkali-activated materials are produced by chemically polymerizing the aluminosilicate materials using alkaline activators, which can effectively lower the greenhouse-gas emissions (approximately 73%) released by ordinary Portland cement (OPC). Silicomanganese slag is a large solid waste discharged from the ferroalloy industry in China that [...] Read more.

Alkali-activated materials are produced by chemically polymerizing the aluminosilicate materials using alkaline activators, which can effectively lower the greenhouse-gas emissions (approximately 73%) released by ordinary Portland cement (OPC). Silicomanganese slag is a large solid waste discharged from the ferroalloy industry in China that can pollute the environment and occupy resources. In this paper, the slag in alkali-activated material was replaced with silicomanganese slag to address the disposal of silicomangaese slag. The flowability, setting times, compressive and flexural strengths, micro-structure and freeze-thaw resistance of alkali-activated silicomanganese slag concrete (AASSC) with varied substitution ratios, volume fractions of steel fibers and alkali-activated modulus (M_S) were exploited. As a results the compressive strengths at 56 days of AASSC with a 10% substitution ratio of silicomanganese slag reached over 80 MPa and over 132 MPa with the 3% steel fiber dosage. AASSC still reached 91 MPa and 45 MPa with 60% and 100% substitution ratios by cooperating 2% steel fibers, respectively. When the freeze-thaw cycle number reached 300, the compressive strengths of AASSC with the replacement ratios of 10%, 60% and 100% were 84%, 74% and 51% of their original values by cooperating 2% steel fibers, respectively; AASSC with the numerous substitutions of 60% and 100% were destroyed at 600 and 300 freeze-thaw cycles, respectively. AASSC with a 10% substitution ratio and 2% steel fiber content is suitable for excellent performance, and a 60% substitution ratio can also be applied to construction for the massive utilization of silicomanganese slag. Full article

(This article belongs to the Special Issue Advanced Composite Materials for Structure Strengthening and Resilience Improving)

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24 pages, 9783 KiB

Open AccessArticle

Flexural Behavior of RC Beams Strengthened with GFRP Laminate and Retrofitting with Novelty of Adhesive Material

by Basem O. Rageh, Mahmoud A. El-Mandouh, Ahmed H. Elmasry and Mohammed M. Attia

Buildings 2022, 12(9), 1444; https://doi.org/10.3390/buildings12091444 - 14 Sep 2022

Cited by 10 | Viewed by 1995

Abstract

Two unique approaches were proposed to strengthen the bond between the glass fiber reinforcement polymer (GFRP) and the RC concrete surfaces. The two bonding materials are epoxy (EP) and geopolymer (GPP) with different ratios of short glass fibers (SGF). The experimental program includes [...] Read more.

Two unique approaches were proposed to strengthen the bond between the glass fiber reinforcement polymer (GFRP) and the RC concrete surfaces. The two bonding materials are epoxy (EP) and geopolymer (GPP) with different ratios of short glass fibers (SGF). The experimental program includes seven reinforced concrete (RC) beams that have the same cross-section (150 mm × 200 mm) and are 1500 mm in length. The first beam is the control beam (B0-Control). The next three beams B1-0-GPP, B2-0.6-GPP, and B3-1.2-GPP have GPP with SGF ratios of 0%, 0.6%, and 1.2%, respectively. The last three beams B4-0-EP, B5-0.6-EP, and B6-1.2-EP have EP with SGF ratios of 0%, 0.6%, and 1.2%, respectively. The results show that the failure loads of beams B1-0-GPP, B2-0.60-GPP, and B3-1.2-GPP are greater than the control beam B0-Control by approximately 20.80%, 25.60%, and 31.40%, respectively, whereas the failure loads of beams B4-0-EP, B5-0.6-EP, and B6-1.2-EP are greater than the B0-Control by approximately 16.90%, 26.90%, and 26.10%, respectively; it is also noted that debonding occurs. In addition to the adhesive material, GPP has a great effect on increasing the beam’s failure load capacity due to the enhanced interfacial bond shear strength. Additionally, a finite-element program ABAQUS is performed to verify the experimental results. Full article

(This article belongs to the Special Issue Advanced Composite Materials for Structure Strengthening and Resilience Improving)

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Review

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31 pages, 8083 KiB

Open AccessReview

Advanced Composite Materials for Structure Strengthening and Resilience Improvement

by Xinghuai Huang, Shaoyang Su, Zhaodong Xu, Qisong Miao, Wenfeng Li and Lixin Wang

Buildings 2023, 13(10), 2406; https://doi.org/10.3390/buildings13102406 - 22 Sep 2023

Cited by 2 | Viewed by 3836

Abstract

Advanced composite materials have excellent performance and broad engineering application prospects, and have received widespread attention in recent years. Advanced composite materials can mainly be divided into fiber-reinforced composite materials, laminated composite materials, matrix composite materials, and other composite materials. This article provides [...] Read more.

Advanced composite materials have excellent performance and broad engineering application prospects, and have received widespread attention in recent years. Advanced composite materials can mainly be divided into fiber-reinforced composite materials, laminated composite materials, matrix composite materials, and other composite materials. This article provides a comprehensive overview of the types and characteristics of advanced composite materials, and provides a comprehensive evaluation of the latest research on structural strengthening and resilience improvement in advanced composite materials from the perspectives of new methods, modeling optimization, and practical applications. In the field of fiber-reinforced composite materials, the hybrid technology of carbon fiber and glass fiber can achieve dual advantages in combining the two materials. The maximum increase in mechanical properties of multilayer sandwich RH plate by hybrid technology is 435.4% (tensile strength), 149.2% (flexural strength), and 110.7~114.2% (shear strength), respectively. In the field of laminated composite materials, different mechanical properties of laminated composite materials can be obtained by changing the deposition sequence. In the field of matrix composites, nano copper oxide particles prepared by nanotechnology can increase the hardness and tensile strength of the metal matrix material by 77% and 78%, respectively. In the field of other composite materials, viscoelastic materials and magnetorheological variants have received widespread attention. The development of composite materials benefits from the promotion of new methods and technologies, but there are still problems such as complex preparation, high cost, and unstable performance. Considering the characteristics, application requirements, cost, complexity, and performance of different types of composite materials, further improvements and innovations are needed in modeling and optimization to better meet practical engineering needs, such as the application of advanced composite materials in civil engineering, ships, automobiles, batteries, and other fields. Full article

(This article belongs to the Special Issue Advanced Composite Materials for Structure Strengthening and Resilience Improving)

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